CA2095449C - Supersaturated rare earth doped semiconductor layers by chemical vapor deposition - Google Patents
Supersaturated rare earth doped semiconductor layers by chemical vapor depositionInfo
- Publication number
- CA2095449C CA2095449C CA002095449A CA2095449A CA2095449C CA 2095449 C CA2095449 C CA 2095449C CA 002095449 A CA002095449 A CA 002095449A CA 2095449 A CA2095449 A CA 2095449A CA 2095449 C CA2095449 C CA 2095449C
- Authority
- CA
- Canada
- Prior art keywords
- erbium
- rare earth
- atoms
- film
- process according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 229910052761 rare earth metal Inorganic materials 0.000 title claims abstract description 71
- 239000004065 semiconductor Substances 0.000 title claims abstract description 53
- 150000002910 rare earth metals Chemical class 0.000 title claims abstract description 40
- 238000005229 chemical vapour deposition Methods 0.000 title claims description 17
- 229910052691 Erbium Inorganic materials 0.000 claims abstract description 80
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 claims abstract description 79
- 238000000034 method Methods 0.000 claims abstract description 57
- 230000008569 process Effects 0.000 claims abstract description 52
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 claims abstract description 47
- 229910052710 silicon Inorganic materials 0.000 claims abstract description 47
- 239000010703 silicon Substances 0.000 claims abstract description 46
- 239000000758 substrate Substances 0.000 claims abstract description 36
- 239000002243 precursor Substances 0.000 claims abstract description 33
- -1 rare earth compound Chemical class 0.000 claims abstract description 23
- BLRPTPMANUNPDV-UHFFFAOYSA-N Silane Chemical compound [SiH4] BLRPTPMANUNPDV-UHFFFAOYSA-N 0.000 claims abstract description 18
- 238000000151 deposition Methods 0.000 claims abstract description 17
- 230000005693 optoelectronics Effects 0.000 claims abstract description 16
- 229910000077 silane Inorganic materials 0.000 claims abstract description 14
- 229910000078 germane Inorganic materials 0.000 claims abstract description 8
- 125000004429 atom Chemical group 0.000 claims description 31
- 229910052760 oxygen Inorganic materials 0.000 claims description 31
- 239000007983 Tris buffer Substances 0.000 claims description 26
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims description 23
- 239000001301 oxygen Substances 0.000 claims description 23
- 239000000203 mixture Substances 0.000 claims description 22
- 125000004430 oxygen atom Chemical group O* 0.000 claims description 16
- 239000002244 precipitate Substances 0.000 claims description 16
- 230000008021 deposition Effects 0.000 claims description 12
- 229910052799 carbon Inorganic materials 0.000 claims description 11
- 229910021332 silicide Inorganic materials 0.000 claims description 11
- FVBUAEGBCNSCDD-UHFFFAOYSA-N silicide(4-) Chemical compound [Si-4] FVBUAEGBCNSCDD-UHFFFAOYSA-N 0.000 claims description 11
- 239000007789 gas Substances 0.000 claims description 10
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 claims description 9
- 125000004432 carbon atom Chemical group C* 0.000 claims description 9
- 229910052732 germanium Inorganic materials 0.000 claims description 9
- GQPLMRYTRLFLPF-UHFFFAOYSA-N Nitrous Oxide Chemical group [O-][N+]#N GQPLMRYTRLFLPF-UHFFFAOYSA-N 0.000 claims description 8
- GNPVGFCGXDBREM-UHFFFAOYSA-N germanium atom Chemical compound [Ge] GNPVGFCGXDBREM-UHFFFAOYSA-N 0.000 claims description 8
- 229910052693 Europium Inorganic materials 0.000 claims description 7
- 229910052771 Terbium Inorganic materials 0.000 claims description 7
- 150000002123 erbium compounds Chemical class 0.000 claims description 7
- OGPBJKLSAFTDLK-UHFFFAOYSA-N europium atom Chemical compound [Eu] OGPBJKLSAFTDLK-UHFFFAOYSA-N 0.000 claims description 7
- 229910052731 fluorine Inorganic materials 0.000 claims description 7
- 239000011737 fluorine Substances 0.000 claims description 7
- GZCRRIHWUXGPOV-UHFFFAOYSA-N terbium atom Chemical compound [Tb] GZCRRIHWUXGPOV-UHFFFAOYSA-N 0.000 claims description 7
- 230000007547 defect Effects 0.000 claims description 5
- 229910052757 nitrogen Inorganic materials 0.000 claims description 5
- 230000001464 adherent effect Effects 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 4
- 239000001272 nitrous oxide Substances 0.000 claims description 4
- 238000005979 thermal decomposition reaction Methods 0.000 claims description 4
- 125000005595 acetylacetonate group Chemical group 0.000 claims description 3
- LXVGPBHPQYZACE-UHFFFAOYSA-N CC1(C=CC=C1)[Er](C1(C=CC=C1)C)C1(C=CC=C1)C Chemical compound CC1(C=CC=C1)[Er](C1(C=CC=C1)C)C1(C=CC=C1)C LXVGPBHPQYZACE-UHFFFAOYSA-N 0.000 claims description 2
- KJQGSQUSWRWGIG-UHFFFAOYSA-N CC1=C(C(=C(C1(C)[Er](C1(C(=C(C(=C1C)C)C)C)C)C1(C(=C(C(=C1C)C)C)C)C)C)C)C Chemical compound CC1=C(C(=C(C1(C)[Er](C1(C(=C(C(=C1C)C)C)C)C)C1(C(=C(C(=C1C)C)C)C)C)C)C)C KJQGSQUSWRWGIG-UHFFFAOYSA-N 0.000 claims description 2
- VTNSPDGNTYHOFK-UHFFFAOYSA-N erbium(3+);2-propan-2-ylcyclopenta-1,3-diene Chemical compound [Er+3].CC(C)C1=[C-]CC=C1.CC(C)C1=[C-]CC=C1.CC(C)C1=[C-]CC=C1 VTNSPDGNTYHOFK-UHFFFAOYSA-N 0.000 claims description 2
- 229910021421 monocrystalline silicon Inorganic materials 0.000 claims description 2
- 150000004756 silanes Chemical class 0.000 claims description 2
- SCCCLDWUZODEKG-UHFFFAOYSA-N germanide Chemical compound [GeH3-] SCCCLDWUZODEKG-UHFFFAOYSA-N 0.000 claims 8
- 125000001153 fluoro group Chemical group F* 0.000 claims 7
- PXGOKWXKJXAPGV-UHFFFAOYSA-N Fluorine Chemical compound FF PXGOKWXKJXAPGV-UHFFFAOYSA-N 0.000 claims 3
- 229910000577 Silicon-germanium Inorganic materials 0.000 claims 3
- LEVVHYCKPQWKOP-UHFFFAOYSA-N [Si].[Ge] Chemical compound [Si].[Ge] LEVVHYCKPQWKOP-UHFFFAOYSA-N 0.000 claims 3
- FZUDUXQEGDBTNS-UHFFFAOYSA-N cyclopenta-1,3-diene;erbium(3+) Chemical compound [Er+3].C=1C=C[CH-]C=1.C=1C=C[CH-]C=1.C=1C=C[CH-]C=1 FZUDUXQEGDBTNS-UHFFFAOYSA-N 0.000 claims 1
- 230000000593 degrading effect Effects 0.000 claims 1
- POILWHVDKZOXJZ-ARJAWSKDSA-M (z)-4-oxopent-2-en-2-olate Chemical compound C\C([O-])=C\C(C)=O POILWHVDKZOXJZ-ARJAWSKDSA-M 0.000 abstract description 4
- QAMFBRUWYYMMGJ-UHFFFAOYSA-N hexafluoroacetylacetone Chemical compound FC(F)(F)C(=O)CC(=O)C(F)(F)F QAMFBRUWYYMMGJ-UHFFFAOYSA-N 0.000 description 15
- 239000003446 ligand Substances 0.000 description 11
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical group N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 8
- 230000003287 optical effect Effects 0.000 description 8
- 230000015572 biosynthetic process Effects 0.000 description 7
- 238000003786 synthesis reaction Methods 0.000 description 7
- 235000012431 wafers Nutrition 0.000 description 7
- 239000013078 crystal Substances 0.000 description 5
- 238000004020 luminiscence type Methods 0.000 description 5
- 239000000463 material Substances 0.000 description 5
- YCKRFDGAMUMZLT-UHFFFAOYSA-N Fluorine atom Chemical compound [F] YCKRFDGAMUMZLT-UHFFFAOYSA-N 0.000 description 4
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N Silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 4
- 150000002500 ions Chemical class 0.000 description 4
- 241000518994 Conta Species 0.000 description 3
- 239000002019 doping agent Substances 0.000 description 3
- 239000012535 impurity Substances 0.000 description 3
- 238000010348 incorporation Methods 0.000 description 3
- 238000005259 measurement Methods 0.000 description 3
- 239000003921 oil Substances 0.000 description 3
- 238000002360 preparation method Methods 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- 238000000038 ultrahigh vacuum chemical vapour deposition Methods 0.000 description 3
- PAYRUJLWNCNPSJ-UHFFFAOYSA-N Aniline Chemical compound NC1=CC=CC=C1 PAYRUJLWNCNPSJ-UHFFFAOYSA-N 0.000 description 2
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 description 2
- XYFCBTPGUUZFHI-UHFFFAOYSA-N Phosphine Chemical compound P XYFCBTPGUUZFHI-UHFFFAOYSA-N 0.000 description 2
- 238000000137 annealing Methods 0.000 description 2
- 230000008901 benefit Effects 0.000 description 2
- 230000005540 biological transmission Effects 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 238000010276 construction Methods 0.000 description 2
- JHFPQYFEJICGKC-UHFFFAOYSA-N erbium(3+) Chemical compound [Er+3] JHFPQYFEJICGKC-UHFFFAOYSA-N 0.000 description 2
- 238000002513 implantation Methods 0.000 description 2
- 238000005468 ion implantation Methods 0.000 description 2
- 238000012986 modification Methods 0.000 description 2
- 230000004048 modification Effects 0.000 description 2
- 239000013307 optical fiber Substances 0.000 description 2
- 238000005424 photoluminescence Methods 0.000 description 2
- 238000005086 pumping Methods 0.000 description 2
- 238000001228 spectrum Methods 0.000 description 2
- 229910001220 stainless steel Inorganic materials 0.000 description 2
- 239000010935 stainless steel Substances 0.000 description 2
- 230000007704 transition Effects 0.000 description 2
- XZPXMWMVWDSEMY-UHFFFAOYSA-N 2,2,3-trimethyloctane Chemical compound CCCCCC(C)C(C)(C)C XZPXMWMVWDSEMY-UHFFFAOYSA-N 0.000 description 1
- SQNZLBOJCWQLGQ-UHFFFAOYSA-N 6,6,7,7,8,8,8-heptafluoro-2,2-dimethyloctane-3,5-dione Chemical compound CC(C)(C)C(=O)CC(=O)C(F)(F)C(F)(F)C(F)(F)F SQNZLBOJCWQLGQ-UHFFFAOYSA-N 0.000 description 1
- 239000004215 Carbon black (E152) Substances 0.000 description 1
- 238000005033 Fourier transform infrared spectroscopy Methods 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- 239000002262 Schiff base Substances 0.000 description 1
- 150000004753 Schiff bases Chemical class 0.000 description 1
- NINIDFKCEFEMDL-UHFFFAOYSA-N Sulfur Chemical group [S] NINIDFKCEFEMDL-UHFFFAOYSA-N 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 125000000217 alkyl group Chemical group 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 239000001273 butane Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000004891 communication Methods 0.000 description 1
- 239000007859 condensation product Substances 0.000 description 1
- 238000011109 contamination Methods 0.000 description 1
- 238000005090 crystal field Methods 0.000 description 1
- 125000000058 cyclopentadienyl group Chemical group C1(=CC=CC1)* 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000013461 design Methods 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- VXGHASBVNMHGDI-UHFFFAOYSA-N digermane Chemical compound [Ge][Ge] VXGHASBVNMHGDI-UHFFFAOYSA-N 0.000 description 1
- YWEUIGNSBFLMFL-UHFFFAOYSA-N diphosphonate Chemical compound O=P(=O)OP(=O)=O YWEUIGNSBFLMFL-UHFFFAOYSA-N 0.000 description 1
- PZPGRFITIJYNEJ-UHFFFAOYSA-N disilane Chemical compound [SiH3][SiH3] PZPGRFITIJYNEJ-UHFFFAOYSA-N 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005401 electroluminescence Methods 0.000 description 1
- 238000002003 electron diffraction Methods 0.000 description 1
- ZSWFCLXCOIISFI-UHFFFAOYSA-N endo-cyclopentadiene Natural products C1C=CC=C1 ZSWFCLXCOIISFI-UHFFFAOYSA-N 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 230000005284 excitation Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- QUZPNFFHZPRKJD-UHFFFAOYSA-N germane Chemical compound [GeH4] QUZPNFFHZPRKJD-UHFFFAOYSA-N 0.000 description 1
- 229910052986 germanium hydride Inorganic materials 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 238000002329 infrared spectrum Methods 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000011068 loading method Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000004682 monohydrates Chemical class 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 150000002902 organometallic compounds Chemical class 0.000 description 1
- 125000002524 organometallic group Chemical group 0.000 description 1
- 239000007800 oxidant agent Substances 0.000 description 1
- 230000001590 oxidative effect Effects 0.000 description 1
- 229910000073 phosphorus hydride Inorganic materials 0.000 description 1
- DLYUQMMRRRQYAE-UHFFFAOYSA-N phosphorus pentoxide Inorganic materials O1P(O2)(=O)OP3(=O)OP1(=O)OP2(=O)O3 DLYUQMMRRRQYAE-UHFFFAOYSA-N 0.000 description 1
- 238000012545 processing Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- 230000005855 radiation Effects 0.000 description 1
- 238000001953 recrystallisation Methods 0.000 description 1
- 238000010992 reflux Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 238000005001 rutherford backscattering spectroscopy Methods 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 238000004611 spectroscopical analysis Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 239000011593 sulfur Chemical group 0.000 description 1
- 229910052717 sulfur Inorganic materials 0.000 description 1
- DPJRMOMPQZCRJU-UHFFFAOYSA-M thiamine hydrochloride Chemical compound Cl.[Cl-].CC1=C(CCO)SC=[N+]1CC1=CN=C(C)N=C1N DPJRMOMPQZCRJU-UHFFFAOYSA-M 0.000 description 1
- 238000011144 upstream manufacturing Methods 0.000 description 1
- 238000009834 vaporization Methods 0.000 description 1
- 230000008016 vaporization Effects 0.000 description 1
Classifications
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L31/00—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof
- H01L31/0248—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies
- H01L31/0256—Semiconductor devices sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation; Processes or apparatus specially adapted for the manufacture or treatment thereof or of parts thereof; Details thereof characterised by their semiconductor bodies characterised by the material
- H01L31/0264—Inorganic materials
- H01L31/028—Inorganic materials including, apart from doping material or other impurities, only elements of Group IV of the Periodic System
- H01L31/0288—Inorganic materials including, apart from doping material or other impurities, only elements of Group IV of the Periodic System characterised by the doping material
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/22—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities
- H01L21/223—Diffusion of impurity materials, e.g. doping materials, electrode materials, into or out of a semiconductor body, or between semiconductor regions; Interactions between two or more impurities; Redistribution of impurities using diffusion into or out of a solid from or into a gaseous phase
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02367—Substrates
- H01L21/0237—Materials
- H01L21/02373—Group 14 semiconducting materials
- H01L21/02381—Silicon, silicon germanium, germanium
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02518—Deposited layers
- H01L21/02521—Materials
- H01L21/02524—Group 14 semiconducting materials
- H01L21/02532—Silicon, silicon germanium, germanium
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02518—Deposited layers
- H01L21/0257—Doping during depositing
- H01L21/02573—Conductivity type
- H01L21/02581—Transition metal or rare earth elements
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/02104—Forming layers
- H01L21/02365—Forming inorganic semiconducting materials on a substrate
- H01L21/02612—Formation types
- H01L21/02617—Deposition types
- H01L21/0262—Reduction or decomposition of gaseous compounds, e.g. CVD
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- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
- H01L21/00—Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
- H01L21/02—Manufacture or treatment of semiconductor devices or of parts thereof
- H01L21/04—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
- H01L21/18—Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
- H01L21/20—Deposition of semiconductor materials on a substrate, e.g. epitaxial growth solid phase epitaxy
- H01L21/205—Deposition of semiconductor materials on a substrate, e.g. epitaxial growth solid phase epitaxy using reduction or decomposition of a gaseous compound yielding a solid condensate, i.e. chemical deposition
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E10/00—Energy generation through renewable energy sources
- Y02E10/50—Photovoltaic [PV] energy
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S252/00—Compositions
- Y10S252/95—Doping agent source material
- Y10S252/951—Doping agent source material for vapor transport
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10S438/00—Semiconductor device manufacturing: process
- Y10S438/914—Doping
- Y10S438/918—Special or nonstandard dopant
Abstract
A CVD process for producing a rare earth-doped, epitaxial semiconductor layer on a substrate is disclosed. The process utilizes a silane or germane and a rare earth compound in the gas phase. By this method single phase, rare earth-doped semiconductor layers, supersaturated in the rare earth, are produced. The preferred rare earth is erbium and the preferred precursors for depositing erbium by CVD are erbium hexafluoroacetylacetonate, acetylacetonate, tetramethylheptanedionate and flurooctanedionate. The process may be used to produce optoelectronic devices comprising a silicon substrate and an erbium-doped epitaxial silicon film.
Description
209~449 SUPERSATURATED RARE EARTH DOPED SF~ICONDUCTOR
LAYERS BY CHEMICAL VAPOR DEPOSITION
Technical Field The invention relates to a CVD process for producing a rare earth-doped, epitaxial semicond~ctor layer on a substrate utilizing a silane or germane and a rare earth compound in the gas phase. By this method single phase, rare earth-doped semiconductor layers, supersaturated in the rare earth, are produced. The process may be used to produce optoelectronic devices comprising a silicon substrate and an erbium-doped epitaxial silicon film.
Backqround Art In recent years increasing research has been focused on the realization of optoelectronic integrated circuits (OE-ICs) on silicon. Possible applications would be chip-to-chip interconnects, parallel processing and the integration of photonics on silicon chips. While the first two applications require basically a light source and a detector on silicon, operating above 77 K, the last application requires the operation of the light source at a certain wavelength, i.e., about 1.5 ~m, which falls in the absorption ini of optical fibers.
In 1983 Ennen et al. lApDl. Phys. Lett. 43, 943 (1983~] pointed out the potential of rare-earth ions in semiconductor materials for the development of light-emitting diodes and lasers. One of the most promising candidates for the preparation of these devices is erbium doping of silicon. The 1.54 ~m r q ~09~4~
luminescence of erbium i8 below the band gap of silicon, thus allowing the construction of optical wave guides within the silicon. This property presents exciting possibilities for creating optical devices in silicon and for integrating electrical and optical devices in circuits fabricated in silicon. The mature manufacturing technology of silicon can be extende~
into optical ~ - ications by this path as the limitation of the silicon indirect band gap is overcome. This wavelength is also ~D~__ tng extremely important in optical communication because it corresponds to a transmission maximum in optical fibers and is also the output of wavelength of IR-pumped Er-doped silica optical amplifiers.
:' The 1.54 ~m luminescence of erbium is the result of an internal 4f transition. The 5s and Sp shells shield the 4f orbitals of the Er3~ from first-order host lattice effects, and, thus, luminescence is fairly in~epDn~ent of the host materials. The optical transitions occur between the spin-orbit levels, ~I13/2 -~I15/2, of Er3~ (4f1t). Since the influence of the crystal field of the host lattice is weak, erbium as an impurity in silicon is expected to show luminescence at room temperature.
Within the past decade, the photo- and electroluminescence, electrical characteristics, and structural properties of Er-doped silicon have been studied. However, prior to the present invention, all Er-doped silicon layers had to be prepared by ion implantation of bulk silicon or by low energy ion implantation of MBE grown silicon. After implantation, samples were annealed to both remove ion damage and to "activate" the implanted erbium. (Activate in the 209~449 : sense of possibly forming an Er-impurity complex which acts as the optical center in these materials.) The best results were obtained at annealing temperatures of 900- C. Unfortunately, erbium possesses a solubility limit in Si of about 1.3 x lO1~ atom/cm3 at 900- C, and ann~Aling results in the formation of platelets of ErSi2 which precipitate out within the silicon phase if the concentration of Er is higher than l.3 x lO1~.
Since higher levels of incorporation of rare earth into epitaxial silicon layers would provide more -~ efficient and powerful devices, there is a need for a process which would produce levels of incorporation . above the present limit of solubility at 900- C.
Disclosure of Invention - 15 We have found that by avoiding the requirement for high temperature annealing and taking advantage of the non-equilibrium nature of chemical vapor deposition (CVD), it is possible to e~ceed the equilibrium cnncentration of dopants to produce metastable, highly doped materials. Thus, ultra high vacuum chemical vapor deposition (~HV~V~) iS used to deposit erbium-doped silicon with an erbium doping level of about 2 x "o lO19 atoms/cm3, an order of magnitude above the equilibrium solid solubility of erbium in silicon.
It is an object of the present invention to provide a process for producing high levels of incorporation of rare earths, particularly erbium, into epitA~iA1 silicon layers.
.
' , 209~44~
Yo9-92-oso -4-It is a further object to provide a process for producing germanium layers conta$ning high levels of erbium.
It is a further object to provide optoelectronic devices having improved GUt~U~ and efficiency.
These and other objects and features are realized in the present invention which relates to a process for creating an erbium-doped semicon~l~ctor layer on a substrate comprising introducing into a CVD chamber a mixture of a first component rhosen from germanes, silanes or mixtures thereof in the ~as phase and a ffecon~ component consisting of an erbium compound in the gas phase and heating the substrate, whereby a deposition film is formed on the substrate. The erbium - 15 ~ 1 has a vapor pressure greater than lo~6 torr at 500- C. In a preferred process a source of oxygen atoms, which may be external (such as NO) or may be the rare earth ligand itself, is provided whereby the resulting silicon or germanium layer comprises erbium and oxygen, in addition to the semiconductor. When the precursor is chosen to include the source of oxygen, preferred precursors are tris(l,l,l,5,5,5-hexafluoro-2,4-pentAneAionato-0,0') erbium, tris(2,4-pentanedionato-O,O')erbium, tris (1,1,1-trifluoropentanedionato-O,O')erbium, tris(l,l,l-trifluoro-5,5-dimethyl-2,4-hexanedionato-O,O')erbium, tris(5,5-dimethyl-2,4-h~Y~nedionato-O,0~)erbium, tris(l-cyclopropyl-4,4,4-trifluoro-1,3-butAne~ionato-- 0,O')erbium, tris(2,2,6-trimethyl-3,5-heptAne~ionato-; 30 0,O')erbium, tris(2,2,6,6-tetramethyl-3,5-heptane~ionato-O,O')erbium, tris(l,l,1,5,5,6,6,7,7,7-decafluoro-2,4-heptanedionato-O,O')erbium~ 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-" ,~
~ ., . .
. .
".
:
~,, 2~44~
octanedionato)erbium and trisl(2-phenyliminomethyl)phenolato-o~N]erbium. When the source of oxygen atoms is external, such as nitrous oxide, preferred precursors are tris(cyclopentadienyl)erblum, tris(pentamethylcyclopentadienyl)erbium, tris(methylcyclopentadienyl)erbium, tris(isopropylcyclopentadienyl)erbium, bis(cyclopentadienyl)erbium halides, and bis(cyclopentadienyl)erbium alkyls.
In a particularly preferred process the silane or germane is SiH~, the erbium ~- ound is tris(l,l,l,5,5,5-hexafluoro-2,4-pentanedionato-0,0') erbiumtEr(HFAC)3], and the erbium-doped semiconductor 15 layer contains more than 1019 atoms/cm3 of erbium and additionally at least 10l8 atoms/cm3 of oxygen. The substrate is heated at 450 to 800- C, preferably at about 650- C and the pressure is maintained at from 10 to 10-9 torr. The silane is provided at a flow rate of 20 1 to 100 sccm, preferably at about 4 sccm when the ; temperature is 650-.
-In another aspect, the invention relates to an optically active epitaxial film comprising silicon and from about 8 x lo1B to about 8 x 1019 atoms/cm3 of 25 erbium, preferably including from 101~ to 1019 atoms/cm3 of oxygen, said film being substantially free of erbium silicide precipitates.
:
In another aspect, the invention relates to an ' optoelectronic device comprising a silicon substrate and an epitaxial silicon film adherent thereon, said film containing from about 8 x 101~ to about 8 x 10~9 , .-' ., YO9-92-090 -6- 2 0 9 ~ 4 4 9 ; atoms cm3 of erbium and said epitaxial film being substantially free of erbium silicide precipitates.
In yet a further aspect the invention relates to a chemical vapor deposition process for creating a rare earth-doped silicon layer on a substrate comprising depositing said layer by the thermal decomposition of a - ga~eon~ precursor mixture of a silane and a rare earth ~ ound. According to the process the rare earth-doped silicon layer may contain the rare earth element 10 in substantially a single phase at a concentration which is higher than the equilibrium concentration for a single phase of that rare earth in silicon.
Preferably the gAseo~c precursor mixture additionally comprises a source of oxygen atoms, which can be the 15 rare earth compound itself. The rare earth c- ,~und is preferably chosen from the group consisting of hexafluoroacetylacetonates, acetylacetonates, tetramethylheptAne~ionates and fluorooctanedionates, and the rare earth is chosen from the group consisting 20 of erbium, terbium and europium.
r Brief DescriD~ion of Drawings " -:
,: ., FIG. 1 is a schematic representation of an ultra ~- high vacuum CVD apparatus useful in the practice of the ~~ invention.
,', ':
FIG. 2 is an IR spectrum of the photoluminescent ouL~uL of a device of the invention.
~, Best Mode for Carrving Out the Invention .. .
- A 7.6 cm diameter ultra high vacuum chemical vapor~ deposition ~UHVCVD) reactor useful for the preparation :
' .', , :
.
' 209~49 Y09-92-Oso -7-of films of the inventlon is depicted in FIG. 1. The reactor differ~ in design from the original UNVCVD
reactor described by Neyerson et al. in that pumping and wafer loa~ing are done using the same end of the reactor. This modification allows the installation of a heated p~e~u~or reservoir 1 on the opposite end of the reactor. The reservoir i8 connected to the reactor end flange usinq a short length of 12.7 mm diameter stainless steel tubing 12. The reactor is constructed of quartz glass and stainless steel, using flanges, valves and seals common to the construction of high vacuum apparatus. The reactor is heated by external resistive heating (tube furnace ~). The reactor is p~ - both before and during deposition by a 150 L/sec turbomolecular pump 8 backed by a two-stage oil pump 9.
The load lock chA ~r is also ~ e~ by a turbomolecular pump lo to prevent contA in~tion from pump oil. The base pressure of the reactor is below 109 torr and the load lock is capable of producing pressures below 10~ torr from atmospheric pressure in less than 10 minutes.
; According to the process of the invention the ;~ precursor reservoir 1 is charged with an appropriate '~: amount of the rare earth compound and evacuated. In a i. ,, preferred embodiment, the rare earth is erbium, although other rare earths, particularly terbium and ' europium may also be used. The rare earths include - elements S7 to 71. The rare earth compounds are y~ restricted in that they must be able to provide a vapor for the CVD process at the temperatures and pressures at which CVD can be run. In a practical sense this means that the rare earth compound should exhibit a vapor p~ ~re of at least about 10~ torr at 500- C.
Exemplary comro~nds fall into two broad categories:
. ~. .
~:' YO9-92-090 -8- 2 0 9 ~ ~ ~ 9 (a) coordination c_ auods, where the rare earth i8 bound to oxygen, nitrogen, sulfur or phosrhorus~ and (b) organometallic ~~ _unds, where the rare earth is bound to carbon atoms. Suitable ligands for the coordination compounds include: acetylacetonate (2,4-pentanedionate) and derivatives of acetylacetonate including hexafluoroacetylacetonate (HFAC, 1,1,1,5,5,5-hexafluoro-2,4-pentAne~ionate) and trifluoroacetylacetonate (TFAC, 1,1,1-trifluoro-2,4-pentanedionate); 2,4-h~YAne~ionate and derivatives of 2,4-hexanedionate; 2,4- and 3,5-heptAne~ionate and derivatives including 2,2,6,6-tetramethyl 3,5-beptAnedionate (THD), 2,2,6-trimethyl 3,5-heptanedionate, and 1,1,1,5,5,6,6,7,7,7-decafluoro 2,4 heptanedionate; 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octanedionate(FOD); and Schiff-base type complexes such as the condensation product of aniline and 2-hydroxyb~nz~ldehyde, which give a bidentate ligand ~ bin~ing through nitrogen and oxygen. Examples of -- 20 organometallic compounds include tris-cyclopentadienyl ~' erbium (III) and organic derivatives of the -~ cyclopentadienyl ring including the tris-pentamethylcyclopentadienyl ligand, the methylcyclopentadienyl ligand, and the '- 25 isopropylcyclopentadienyl ligand, bis(cyclopentadienyl)erbium halides, and bis-~' (cyclopentadienyl)erbium alkyls, wherein alkyl is defined as a linear or brAnch~d hydrocarbon radical of one to six carbon atoms. Preferred ligands include acetylacetonate, HFAC, THD and FOD.
~; From the literature it AppeArs that the inclusion of oxygen (and perhaps carbon, nitrogen and fluorine as well) along with erbium gives rise to enh~nce~
photolum~nesc~nce. For this reason it is desirable to , 2~9~9 provide a source of oxygen for the CVD film This can be achieved either by introducin~ a gaseous source of oxygen, such as nitrous oxide, or by using a precursor compound that contains oxygen, such as the ligands discussed above. In either case, when the precursor is thermally decomposed on the substrate, a film containing both rare earth atoms and oxygen (or other "impurity" atoms) will be deposited.
The substrate is loaded onto the quartz wafer boat 3, placed in the load-lock ch~ 'cr 2 and evacuated to a suitable pressure, preferably less than 10-5 torr. The substrate can be any material that is compatible with the CVD conditions; single-crystal silicon wafers are preferred. In general, a better film is produced when the substrate wafer has been previously cleaned in the ; usual manner.
A precursor gas for the semiconductor film is introduced into the reactor. The precursor can be any silane or germane or mixture of the two that is volatile under the conditions of CVD; silane (SiH4), disilane (Si2H~), germane (GeH4) and digermane (Ge2H6) are preferred. Group III dopant precursors, such as diborane, or group V dopant precursors, such as phosphine, may be introduced to alter the electrical properties of the films. The semiconductor precursor gases are introduced via gas inlet 11 into the reactor.
~~ The temperature of the reactor is maintained at 450- to 800- C. Below 450- epitaxial growth of Si, Ge, or Si/Ge is not observed; as 900- C is approached, erbium begins to segregate. The pressure in the load-. ~ .
- lock chamber 2 before introducing the substrate into the reactor is preferably below 105 torr.
209~49 Y09-92-090 -lo-After the substrate is moved through the gate valve 5 into the reactor chamber 13 by the magnetically coupled manipulator 6, the rare earth precursor is vaporized into the reaction chamber from the reservoir 1 by applying heat. In the embodiment shown in FIG. 1 the heat is supplied by an external oven 7 suL~o~ ing the reservoir. In the case of Er(HFAC)3, the optimal rate of vaporization is obtained when the oven is held at 58- C. Regulation of the precursor reservoir temperature, and hence regulation of the part~al pressure of precursor in the reactor, is important to the success of the process. In the case of Er(HFAC) 3, at temperatures below 55- C, no erbium was incorporated. Above 65- C, the films consisted of a polycrystalline layer 300 to 400 A thick with a , conc~ntration of erbium of 10 to 20%. The thickness of this layer did not increase with longer deposition ~- times, indicating that the growth surface was "poisoned" by the precursor. The likely explanation for this observation is that there is a minimum growth rate above which the erbium and other elements from the ....
precursor may be incorporated and below which the growth surface is poisoned. (The growth rate of pure silicon from silane at 1 mtorr pressure is 4 A/min at 550- C and 40 A/min at 650- C.) The selection of the appropriate oven temperature for a given rare earth compound is readily determined empirically as part of the routine adjustment of experimental conditions.
~' Re~AsonAhle temperatures can be calculated by comparison of the vapor pressure of the precursor of interest at the pressure of the reservoir with the vapor pressure of Er(HFAC)~ at 58-/1 torr.
Yo9-92-o9O -11- 2 0 9 ~ ~ 4 9 ~perimental Results The precursor reservoir was charged with l.Og of anhydrous tris(hexafluoroacetylacetonato-0,0') erbium (III) and evacuated. Four 2.25 inch diameter Si wafers which had previously been cleaned and A i pped in 10%
hydrofluoric acid until the ~urface became hy~ophobic were iD ediately placed in the reactor load-lock. The flow of silane (4 sccm) and h~d~cj~l) (50 sccm) was started, and the valve to the room-temperature erbium source was opened. After a ten minute pump down in the load-lock the wafers were transferred to the reactor.
Three minutes after loading, the flow of hydrogen was stopped and the temperature of the reactor was increased from 500- c to 650- C over a period of one ' 15 hour. With the reactor at 650- C, the temperature of the oven ~Ul lounding the precursor was increased to 58-~m C, directly subliming Er(HFAC)3 into the reactor. The ~- pressure during deposition was 1.5 torr, giving a --~ calculated system pumping speed of 42 L/sec. The deposition rate under these conditions was approximately 30 A/min and deposition times varied from 3 to 12 hours. The flow of silane was discontinued, and the wafers were withdrawn to the load-lock chamber to cool.
~ 25 The composition of the films was determined using -~ Rutherford Back Scattering spectroscopy (R~S) to , determine the erbium concentration and Secondary Ion Hass Spectroscopy (SIMS) to determine the level of carbon, fluorine and oxygen present in the films.
Films produced under the conditions described above (evaporator temperature (T.~ - 58' C, substrate temperature (T,) - 650- C) had a uniform ~rbium cGr.c~ ration of 2 x 1019 atoms/cm2 with carbon, fluorine and oxygen level~ of approximately 4 x 1019 atoms/cm3. The carbon, oxygen, and fluorine levels were equal in the three samples measured, within the uncertainty of the measurement. These Uimpurities'' arise from the decomposition of the precursor.
Transmission Electron Mic~osco~y (TEM) was ; performed on two of the samples. Sample 1 was a 2.7 ~m thick film (T~ = 60- C, T5 5 6S0- C, Er concentration = 8 x 1019 atoms/cm~) deposited on Si(100). Electron diffraction indicated that the film was epitaxial but also showed the presence of a secon~
phase readily assignable as ErSi2. The corresponding electron image indicated the crystal quality of the - layer was extremely poor. Sample 2 was a 2 ~m thick - film produced by lowering T~ by 2- C and growing for longer time (11 h instead of 3 h). The cross sectional TEM of this film does not show any precipitated ErSi2. The erbium concentration of sample 2 was 2 x 1019 atoms/cm3. This level is at least one order of magnitude higher than the highest concentrations reported using implantation techniques.
The cross-sectional TEM also shows a high density of j threading defects. These defects may be due to stress caused by the introduction of erbium (or erbium complexes) into the film, but it is more likely that these defects are due to contA inAtion from the precursor. At the temperatures used in UHVCVD, the crystal quality is very sensitive to the presence of carbon and oxygen and the SIMS results indicate that ;- these elements are present in relatively high conc~ rations. One other possible source of contamination is residual carbon and o~y~,en from the -c pcsition of the ligand upstream from the deposition zone. The Er(HFAC)~ complex decomposes in parts of the reactor which are as much as 300- C cooler "
'' .,~
,:
YO9-92-090 -13- ~ 0 9 5 4 ~ 9 and may continue to evolve small quantities of organic material which may contaminate the initial growth surface. Support for this hypothesis is given by TEM
which shows that the defects occur abruptly and at highest concentration at the initial growth interface.
In this respect there may be an advantage to other precursors, particularly of the org~n. -tallic type, when used together with conL~olled levels of oxidant gas.
Rare earth compounds can be prepared by methods well known in the art. The Er(HFAC)~ used in the foregoing experiment was made by a modification of the known process for the synthesis of Al(HFAC)3 described by Morris et al. in Inorqanic Syntheses, Vol. 9, S.Y.
Tyree, editor; McGraw Hill, New York, (1967) p. 39.
This synthesis is an improvement over the synthesis of Er(HFAC)3 described by ~erg and Acosta tAnal. Chim.
~, Acta. 40, 101, tl968)] in that it is carried out under ., nonaqueous conditions; it thus avoids the intermediate synthesis of Er(HFAC)3 monohydrate which must be dehydrated over phosphorus pentoxide under vacuum at elevated temperatures before it can be used in a CVD
;~ process. The new synthesis is also considerably faster ~' and easier than the literature preparation, which ~- 25 yields a difficult to handle mixture of crystals and ~ oil requiring several recrystallizations with significant loss of product at each step. All manipulations were carried out under nitrogen using standard Schlenk-line and dry-box techniques.
Ercl~+3c5H2F6o2~ErtcsHF6o2)3+3Hcl A 200 mL, three-neck flask e~lippe~ with a reflux conde:--er, pressure-equalizing dropping funnel, and qas Y09-92-090 -14- 2Q9~49 inlet was charged with 4.11 g (.015 mol) of anhydrous ErC13 in 100 mL of a CCl~. To the stirred su~pension was added 9.57g (0.046 mol) of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione. After several minutes, the solution turned from colorless to faint pink and HCl gas was evolved. Following the addition of the ligand, the solution was refluxed for 1 hour. The hot solution was suction filtered and cooled to -10- C for 6 hours.
Pink crystals were observed to form in the flask. The - 10 crystals were filtered, washed with cold CCl~ and sublimed twice at 100- C at lo~2 torr. A yield of 7.9 g (67%) of pure Er(HFAC)3 was obtained.
It is contemplated that the foregoing synthesis could be used in similar fashion to prepare other complexes with other rare earths by substituting the appropriate rare earth trichloride for ErC13 and the appropriate ligand for HFAC.
Photoluminescence measurements were carried out on several of the samples. Neasurements were done using an Ar ion laser operating at 514 nm as the excitation source and a Cygnus FTIR to detect the emitted - radiation. A representative spectrum of a 2 ~m film with an Er concentration of 2 x 1019 atoms/cm3 (identical to the sample used for TEM measurements above) is shown in FIG. 2. This spectrum was obtained at 10 K and the luminescence fell sharply as the temperature was raised. At 200 K, the signal intensity -~ was down by a factor of S0 and was not observable at room temperature.
.
Y09-92-oso -15- ~ 0 9 5 4 ~ ~
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that other changes in form and details may be made therein without departing from the spirit and scope of : the invention.
. ., ., .:,
LAYERS BY CHEMICAL VAPOR DEPOSITION
Technical Field The invention relates to a CVD process for producing a rare earth-doped, epitaxial semicond~ctor layer on a substrate utilizing a silane or germane and a rare earth compound in the gas phase. By this method single phase, rare earth-doped semiconductor layers, supersaturated in the rare earth, are produced. The process may be used to produce optoelectronic devices comprising a silicon substrate and an erbium-doped epitaxial silicon film.
Backqround Art In recent years increasing research has been focused on the realization of optoelectronic integrated circuits (OE-ICs) on silicon. Possible applications would be chip-to-chip interconnects, parallel processing and the integration of photonics on silicon chips. While the first two applications require basically a light source and a detector on silicon, operating above 77 K, the last application requires the operation of the light source at a certain wavelength, i.e., about 1.5 ~m, which falls in the absorption ini of optical fibers.
In 1983 Ennen et al. lApDl. Phys. Lett. 43, 943 (1983~] pointed out the potential of rare-earth ions in semiconductor materials for the development of light-emitting diodes and lasers. One of the most promising candidates for the preparation of these devices is erbium doping of silicon. The 1.54 ~m r q ~09~4~
luminescence of erbium i8 below the band gap of silicon, thus allowing the construction of optical wave guides within the silicon. This property presents exciting possibilities for creating optical devices in silicon and for integrating electrical and optical devices in circuits fabricated in silicon. The mature manufacturing technology of silicon can be extende~
into optical ~ - ications by this path as the limitation of the silicon indirect band gap is overcome. This wavelength is also ~D~__ tng extremely important in optical communication because it corresponds to a transmission maximum in optical fibers and is also the output of wavelength of IR-pumped Er-doped silica optical amplifiers.
:' The 1.54 ~m luminescence of erbium is the result of an internal 4f transition. The 5s and Sp shells shield the 4f orbitals of the Er3~ from first-order host lattice effects, and, thus, luminescence is fairly in~epDn~ent of the host materials. The optical transitions occur between the spin-orbit levels, ~I13/2 -~I15/2, of Er3~ (4f1t). Since the influence of the crystal field of the host lattice is weak, erbium as an impurity in silicon is expected to show luminescence at room temperature.
Within the past decade, the photo- and electroluminescence, electrical characteristics, and structural properties of Er-doped silicon have been studied. However, prior to the present invention, all Er-doped silicon layers had to be prepared by ion implantation of bulk silicon or by low energy ion implantation of MBE grown silicon. After implantation, samples were annealed to both remove ion damage and to "activate" the implanted erbium. (Activate in the 209~449 : sense of possibly forming an Er-impurity complex which acts as the optical center in these materials.) The best results were obtained at annealing temperatures of 900- C. Unfortunately, erbium possesses a solubility limit in Si of about 1.3 x lO1~ atom/cm3 at 900- C, and ann~Aling results in the formation of platelets of ErSi2 which precipitate out within the silicon phase if the concentration of Er is higher than l.3 x lO1~.
Since higher levels of incorporation of rare earth into epitaxial silicon layers would provide more -~ efficient and powerful devices, there is a need for a process which would produce levels of incorporation . above the present limit of solubility at 900- C.
Disclosure of Invention - 15 We have found that by avoiding the requirement for high temperature annealing and taking advantage of the non-equilibrium nature of chemical vapor deposition (CVD), it is possible to e~ceed the equilibrium cnncentration of dopants to produce metastable, highly doped materials. Thus, ultra high vacuum chemical vapor deposition (~HV~V~) iS used to deposit erbium-doped silicon with an erbium doping level of about 2 x "o lO19 atoms/cm3, an order of magnitude above the equilibrium solid solubility of erbium in silicon.
It is an object of the present invention to provide a process for producing high levels of incorporation of rare earths, particularly erbium, into epitA~iA1 silicon layers.
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' , 209~44~
Yo9-92-oso -4-It is a further object to provide a process for producing germanium layers conta$ning high levels of erbium.
It is a further object to provide optoelectronic devices having improved GUt~U~ and efficiency.
These and other objects and features are realized in the present invention which relates to a process for creating an erbium-doped semicon~l~ctor layer on a substrate comprising introducing into a CVD chamber a mixture of a first component rhosen from germanes, silanes or mixtures thereof in the ~as phase and a ffecon~ component consisting of an erbium compound in the gas phase and heating the substrate, whereby a deposition film is formed on the substrate. The erbium - 15 ~ 1 has a vapor pressure greater than lo~6 torr at 500- C. In a preferred process a source of oxygen atoms, which may be external (such as NO) or may be the rare earth ligand itself, is provided whereby the resulting silicon or germanium layer comprises erbium and oxygen, in addition to the semiconductor. When the precursor is chosen to include the source of oxygen, preferred precursors are tris(l,l,l,5,5,5-hexafluoro-2,4-pentAneAionato-0,0') erbium, tris(2,4-pentanedionato-O,O')erbium, tris (1,1,1-trifluoropentanedionato-O,O')erbium, tris(l,l,l-trifluoro-5,5-dimethyl-2,4-hexanedionato-O,O')erbium, tris(5,5-dimethyl-2,4-h~Y~nedionato-O,0~)erbium, tris(l-cyclopropyl-4,4,4-trifluoro-1,3-butAne~ionato-- 0,O')erbium, tris(2,2,6-trimethyl-3,5-heptAne~ionato-; 30 0,O')erbium, tris(2,2,6,6-tetramethyl-3,5-heptane~ionato-O,O')erbium, tris(l,l,1,5,5,6,6,7,7,7-decafluoro-2,4-heptanedionato-O,O')erbium~ 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-" ,~
~ ., . .
. .
".
:
~,, 2~44~
octanedionato)erbium and trisl(2-phenyliminomethyl)phenolato-o~N]erbium. When the source of oxygen atoms is external, such as nitrous oxide, preferred precursors are tris(cyclopentadienyl)erblum, tris(pentamethylcyclopentadienyl)erbium, tris(methylcyclopentadienyl)erbium, tris(isopropylcyclopentadienyl)erbium, bis(cyclopentadienyl)erbium halides, and bis(cyclopentadienyl)erbium alkyls.
In a particularly preferred process the silane or germane is SiH~, the erbium ~- ound is tris(l,l,l,5,5,5-hexafluoro-2,4-pentanedionato-0,0') erbiumtEr(HFAC)3], and the erbium-doped semiconductor 15 layer contains more than 1019 atoms/cm3 of erbium and additionally at least 10l8 atoms/cm3 of oxygen. The substrate is heated at 450 to 800- C, preferably at about 650- C and the pressure is maintained at from 10 to 10-9 torr. The silane is provided at a flow rate of 20 1 to 100 sccm, preferably at about 4 sccm when the ; temperature is 650-.
-In another aspect, the invention relates to an optically active epitaxial film comprising silicon and from about 8 x lo1B to about 8 x 1019 atoms/cm3 of 25 erbium, preferably including from 101~ to 1019 atoms/cm3 of oxygen, said film being substantially free of erbium silicide precipitates.
:
In another aspect, the invention relates to an ' optoelectronic device comprising a silicon substrate and an epitaxial silicon film adherent thereon, said film containing from about 8 x 101~ to about 8 x 10~9 , .-' ., YO9-92-090 -6- 2 0 9 ~ 4 4 9 ; atoms cm3 of erbium and said epitaxial film being substantially free of erbium silicide precipitates.
In yet a further aspect the invention relates to a chemical vapor deposition process for creating a rare earth-doped silicon layer on a substrate comprising depositing said layer by the thermal decomposition of a - ga~eon~ precursor mixture of a silane and a rare earth ~ ound. According to the process the rare earth-doped silicon layer may contain the rare earth element 10 in substantially a single phase at a concentration which is higher than the equilibrium concentration for a single phase of that rare earth in silicon.
Preferably the gAseo~c precursor mixture additionally comprises a source of oxygen atoms, which can be the 15 rare earth compound itself. The rare earth c- ,~und is preferably chosen from the group consisting of hexafluoroacetylacetonates, acetylacetonates, tetramethylheptAne~ionates and fluorooctanedionates, and the rare earth is chosen from the group consisting 20 of erbium, terbium and europium.
r Brief DescriD~ion of Drawings " -:
,: ., FIG. 1 is a schematic representation of an ultra ~- high vacuum CVD apparatus useful in the practice of the ~~ invention.
,', ':
FIG. 2 is an IR spectrum of the photoluminescent ouL~uL of a device of the invention.
~, Best Mode for Carrving Out the Invention .. .
- A 7.6 cm diameter ultra high vacuum chemical vapor~ deposition ~UHVCVD) reactor useful for the preparation :
' .', , :
.
' 209~49 Y09-92-Oso -7-of films of the inventlon is depicted in FIG. 1. The reactor differ~ in design from the original UNVCVD
reactor described by Neyerson et al. in that pumping and wafer loa~ing are done using the same end of the reactor. This modification allows the installation of a heated p~e~u~or reservoir 1 on the opposite end of the reactor. The reservoir i8 connected to the reactor end flange usinq a short length of 12.7 mm diameter stainless steel tubing 12. The reactor is constructed of quartz glass and stainless steel, using flanges, valves and seals common to the construction of high vacuum apparatus. The reactor is heated by external resistive heating (tube furnace ~). The reactor is p~ - both before and during deposition by a 150 L/sec turbomolecular pump 8 backed by a two-stage oil pump 9.
The load lock chA ~r is also ~ e~ by a turbomolecular pump lo to prevent contA in~tion from pump oil. The base pressure of the reactor is below 109 torr and the load lock is capable of producing pressures below 10~ torr from atmospheric pressure in less than 10 minutes.
; According to the process of the invention the ;~ precursor reservoir 1 is charged with an appropriate '~: amount of the rare earth compound and evacuated. In a i. ,, preferred embodiment, the rare earth is erbium, although other rare earths, particularly terbium and ' europium may also be used. The rare earths include - elements S7 to 71. The rare earth compounds are y~ restricted in that they must be able to provide a vapor for the CVD process at the temperatures and pressures at which CVD can be run. In a practical sense this means that the rare earth compound should exhibit a vapor p~ ~re of at least about 10~ torr at 500- C.
Exemplary comro~nds fall into two broad categories:
. ~. .
~:' YO9-92-090 -8- 2 0 9 ~ ~ ~ 9 (a) coordination c_ auods, where the rare earth i8 bound to oxygen, nitrogen, sulfur or phosrhorus~ and (b) organometallic ~~ _unds, where the rare earth is bound to carbon atoms. Suitable ligands for the coordination compounds include: acetylacetonate (2,4-pentanedionate) and derivatives of acetylacetonate including hexafluoroacetylacetonate (HFAC, 1,1,1,5,5,5-hexafluoro-2,4-pentAne~ionate) and trifluoroacetylacetonate (TFAC, 1,1,1-trifluoro-2,4-pentanedionate); 2,4-h~YAne~ionate and derivatives of 2,4-hexanedionate; 2,4- and 3,5-heptAne~ionate and derivatives including 2,2,6,6-tetramethyl 3,5-beptAnedionate (THD), 2,2,6-trimethyl 3,5-heptanedionate, and 1,1,1,5,5,6,6,7,7,7-decafluoro 2,4 heptanedionate; 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octanedionate(FOD); and Schiff-base type complexes such as the condensation product of aniline and 2-hydroxyb~nz~ldehyde, which give a bidentate ligand ~ bin~ing through nitrogen and oxygen. Examples of -- 20 organometallic compounds include tris-cyclopentadienyl ~' erbium (III) and organic derivatives of the -~ cyclopentadienyl ring including the tris-pentamethylcyclopentadienyl ligand, the methylcyclopentadienyl ligand, and the '- 25 isopropylcyclopentadienyl ligand, bis(cyclopentadienyl)erbium halides, and bis-~' (cyclopentadienyl)erbium alkyls, wherein alkyl is defined as a linear or brAnch~d hydrocarbon radical of one to six carbon atoms. Preferred ligands include acetylacetonate, HFAC, THD and FOD.
~; From the literature it AppeArs that the inclusion of oxygen (and perhaps carbon, nitrogen and fluorine as well) along with erbium gives rise to enh~nce~
photolum~nesc~nce. For this reason it is desirable to , 2~9~9 provide a source of oxygen for the CVD film This can be achieved either by introducin~ a gaseous source of oxygen, such as nitrous oxide, or by using a precursor compound that contains oxygen, such as the ligands discussed above. In either case, when the precursor is thermally decomposed on the substrate, a film containing both rare earth atoms and oxygen (or other "impurity" atoms) will be deposited.
The substrate is loaded onto the quartz wafer boat 3, placed in the load-lock ch~ 'cr 2 and evacuated to a suitable pressure, preferably less than 10-5 torr. The substrate can be any material that is compatible with the CVD conditions; single-crystal silicon wafers are preferred. In general, a better film is produced when the substrate wafer has been previously cleaned in the ; usual manner.
A precursor gas for the semiconductor film is introduced into the reactor. The precursor can be any silane or germane or mixture of the two that is volatile under the conditions of CVD; silane (SiH4), disilane (Si2H~), germane (GeH4) and digermane (Ge2H6) are preferred. Group III dopant precursors, such as diborane, or group V dopant precursors, such as phosphine, may be introduced to alter the electrical properties of the films. The semiconductor precursor gases are introduced via gas inlet 11 into the reactor.
~~ The temperature of the reactor is maintained at 450- to 800- C. Below 450- epitaxial growth of Si, Ge, or Si/Ge is not observed; as 900- C is approached, erbium begins to segregate. The pressure in the load-. ~ .
- lock chamber 2 before introducing the substrate into the reactor is preferably below 105 torr.
209~49 Y09-92-090 -lo-After the substrate is moved through the gate valve 5 into the reactor chamber 13 by the magnetically coupled manipulator 6, the rare earth precursor is vaporized into the reaction chamber from the reservoir 1 by applying heat. In the embodiment shown in FIG. 1 the heat is supplied by an external oven 7 suL~o~ ing the reservoir. In the case of Er(HFAC)3, the optimal rate of vaporization is obtained when the oven is held at 58- C. Regulation of the precursor reservoir temperature, and hence regulation of the part~al pressure of precursor in the reactor, is important to the success of the process. In the case of Er(HFAC) 3, at temperatures below 55- C, no erbium was incorporated. Above 65- C, the films consisted of a polycrystalline layer 300 to 400 A thick with a , conc~ntration of erbium of 10 to 20%. The thickness of this layer did not increase with longer deposition ~- times, indicating that the growth surface was "poisoned" by the precursor. The likely explanation for this observation is that there is a minimum growth rate above which the erbium and other elements from the ....
precursor may be incorporated and below which the growth surface is poisoned. (The growth rate of pure silicon from silane at 1 mtorr pressure is 4 A/min at 550- C and 40 A/min at 650- C.) The selection of the appropriate oven temperature for a given rare earth compound is readily determined empirically as part of the routine adjustment of experimental conditions.
~' Re~AsonAhle temperatures can be calculated by comparison of the vapor pressure of the precursor of interest at the pressure of the reservoir with the vapor pressure of Er(HFAC)~ at 58-/1 torr.
Yo9-92-o9O -11- 2 0 9 ~ ~ 4 9 ~perimental Results The precursor reservoir was charged with l.Og of anhydrous tris(hexafluoroacetylacetonato-0,0') erbium (III) and evacuated. Four 2.25 inch diameter Si wafers which had previously been cleaned and A i pped in 10%
hydrofluoric acid until the ~urface became hy~ophobic were iD ediately placed in the reactor load-lock. The flow of silane (4 sccm) and h~d~cj~l) (50 sccm) was started, and the valve to the room-temperature erbium source was opened. After a ten minute pump down in the load-lock the wafers were transferred to the reactor.
Three minutes after loading, the flow of hydrogen was stopped and the temperature of the reactor was increased from 500- c to 650- C over a period of one ' 15 hour. With the reactor at 650- C, the temperature of the oven ~Ul lounding the precursor was increased to 58-~m C, directly subliming Er(HFAC)3 into the reactor. The ~- pressure during deposition was 1.5 torr, giving a --~ calculated system pumping speed of 42 L/sec. The deposition rate under these conditions was approximately 30 A/min and deposition times varied from 3 to 12 hours. The flow of silane was discontinued, and the wafers were withdrawn to the load-lock chamber to cool.
~ 25 The composition of the films was determined using -~ Rutherford Back Scattering spectroscopy (R~S) to , determine the erbium concentration and Secondary Ion Hass Spectroscopy (SIMS) to determine the level of carbon, fluorine and oxygen present in the films.
Films produced under the conditions described above (evaporator temperature (T.~ - 58' C, substrate temperature (T,) - 650- C) had a uniform ~rbium cGr.c~ ration of 2 x 1019 atoms/cm2 with carbon, fluorine and oxygen level~ of approximately 4 x 1019 atoms/cm3. The carbon, oxygen, and fluorine levels were equal in the three samples measured, within the uncertainty of the measurement. These Uimpurities'' arise from the decomposition of the precursor.
Transmission Electron Mic~osco~y (TEM) was ; performed on two of the samples. Sample 1 was a 2.7 ~m thick film (T~ = 60- C, T5 5 6S0- C, Er concentration = 8 x 1019 atoms/cm~) deposited on Si(100). Electron diffraction indicated that the film was epitaxial but also showed the presence of a secon~
phase readily assignable as ErSi2. The corresponding electron image indicated the crystal quality of the - layer was extremely poor. Sample 2 was a 2 ~m thick - film produced by lowering T~ by 2- C and growing for longer time (11 h instead of 3 h). The cross sectional TEM of this film does not show any precipitated ErSi2. The erbium concentration of sample 2 was 2 x 1019 atoms/cm3. This level is at least one order of magnitude higher than the highest concentrations reported using implantation techniques.
The cross-sectional TEM also shows a high density of j threading defects. These defects may be due to stress caused by the introduction of erbium (or erbium complexes) into the film, but it is more likely that these defects are due to contA inAtion from the precursor. At the temperatures used in UHVCVD, the crystal quality is very sensitive to the presence of carbon and oxygen and the SIMS results indicate that ;- these elements are present in relatively high conc~ rations. One other possible source of contamination is residual carbon and o~y~,en from the -c pcsition of the ligand upstream from the deposition zone. The Er(HFAC)~ complex decomposes in parts of the reactor which are as much as 300- C cooler "
'' .,~
,:
YO9-92-090 -13- ~ 0 9 5 4 ~ 9 and may continue to evolve small quantities of organic material which may contaminate the initial growth surface. Support for this hypothesis is given by TEM
which shows that the defects occur abruptly and at highest concentration at the initial growth interface.
In this respect there may be an advantage to other precursors, particularly of the org~n. -tallic type, when used together with conL~olled levels of oxidant gas.
Rare earth compounds can be prepared by methods well known in the art. The Er(HFAC)~ used in the foregoing experiment was made by a modification of the known process for the synthesis of Al(HFAC)3 described by Morris et al. in Inorqanic Syntheses, Vol. 9, S.Y.
Tyree, editor; McGraw Hill, New York, (1967) p. 39.
This synthesis is an improvement over the synthesis of Er(HFAC)3 described by ~erg and Acosta tAnal. Chim.
~, Acta. 40, 101, tl968)] in that it is carried out under ., nonaqueous conditions; it thus avoids the intermediate synthesis of Er(HFAC)3 monohydrate which must be dehydrated over phosphorus pentoxide under vacuum at elevated temperatures before it can be used in a CVD
;~ process. The new synthesis is also considerably faster ~' and easier than the literature preparation, which ~- 25 yields a difficult to handle mixture of crystals and ~ oil requiring several recrystallizations with significant loss of product at each step. All manipulations were carried out under nitrogen using standard Schlenk-line and dry-box techniques.
Ercl~+3c5H2F6o2~ErtcsHF6o2)3+3Hcl A 200 mL, three-neck flask e~lippe~ with a reflux conde:--er, pressure-equalizing dropping funnel, and qas Y09-92-090 -14- 2Q9~49 inlet was charged with 4.11 g (.015 mol) of anhydrous ErC13 in 100 mL of a CCl~. To the stirred su~pension was added 9.57g (0.046 mol) of 1,1,1,5,5,5-hexafluoro-2,4-pentanedione. After several minutes, the solution turned from colorless to faint pink and HCl gas was evolved. Following the addition of the ligand, the solution was refluxed for 1 hour. The hot solution was suction filtered and cooled to -10- C for 6 hours.
Pink crystals were observed to form in the flask. The - 10 crystals were filtered, washed with cold CCl~ and sublimed twice at 100- C at lo~2 torr. A yield of 7.9 g (67%) of pure Er(HFAC)3 was obtained.
It is contemplated that the foregoing synthesis could be used in similar fashion to prepare other complexes with other rare earths by substituting the appropriate rare earth trichloride for ErC13 and the appropriate ligand for HFAC.
Photoluminescence measurements were carried out on several of the samples. Neasurements were done using an Ar ion laser operating at 514 nm as the excitation source and a Cygnus FTIR to detect the emitted - radiation. A representative spectrum of a 2 ~m film with an Er concentration of 2 x 1019 atoms/cm3 (identical to the sample used for TEM measurements above) is shown in FIG. 2. This spectrum was obtained at 10 K and the luminescence fell sharply as the temperature was raised. At 200 K, the signal intensity -~ was down by a factor of S0 and was not observable at room temperature.
.
Y09-92-oso -15- ~ 0 9 5 4 ~ ~
While the invention has been particularly shown and described with reference to preferred embodiments thereof, it will be understood by those skilled in the art that other changes in form and details may be made therein without departing from the spirit and scope of : the invention.
. ., ., .:,
Claims (70)
1. A process for creating an erbium-doped semiconductor layer on a substrate comprising introducing into a film-forming chamber for forming a deposition film on a substrate a mixture of a first component chosen from the group consisting of germanes, silanes and mixtures thereof in the gas phase and a second component consisting of an erbium compound in the gas phase and heating said substrate, whereby a deposition film is formed on said substrate, said erbium compound having a vapor pressure greater than 10-6 torr at 500°C.
2. A process according to claim 1 additionally including the steps of introducing a source of oxygen atoms into said film-forming chamber whereby said semiconductor layer comprises said semiconductor, erbium and oxygen.
3. A process according to claim 2 wherein said source of oxygen atoms is said erbium compound.
4. A process according to claim 3 wherein said erbium compound is chosen from the group consisting of tris(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato-0,0') erbium, tris(2,4-pentanedionato-O,O')erbium, tris ( 1,1,1-trifluoropentanedionato-O,O')erbium, tris( 1,1,1-trifluoro-5,5-dimethyl-2,4-hexanedionato-O,O')erbium, tris(5,5-dimethyl-2,4-hexanedionato-0,0') erbium, tris( 1-cyclopropyl-4,4,4-trifluoro-1,3-butanedionato-0,0')erbium, tris(2,2,6-trimethyl-3,5-heptanedionato-0,0')erbium, tris(2,2,6,6-tetramethyl-3,5-heptanedionato-0,0') erbium, tris(1,1,1,5,5,6,6,7,7,7-decafluoro-2,4-heptanedionato-0,0')erbium, 2, 2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3, 5-octanedionato-0,0')erbium and tris[(2-phenyliminomethyl)phenolato-O,N]erbium.
5. A process according to claim 4 wherein said silane or germane is SiH4 and said erbium compound is tris(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato-0,00')erbium.
6. A process according to claim 1 wherein said erbium-doped semiconductor layer contains more than 10 19 atoms/cm3 of erbium.
7. A process according to claim 6 wherein said erbium-doped semiconductor layer additionally contains at least 10 18 atoms/cm3 of oxygen.
8. A process according to claim 1 wherein said substrate is heated at 450° to 800°C.
9. A process according to claim 2 wherein said source of oxygen atoms is a third gaseous component.
10. A process according to claim 9 wherein said third gaseous component is nitrous oxide.
11. A process according to claim 9 wherein said erbium compound is chosen from the group consisting of tris(cyclopentadienyl)erbium, tris(pentamethylcyclopentadienyl)erbium, tris(methylcyclopentadienyl)erbium, tris(isopropylcyclopentadienyl)erbium, bis(cyclopentadienyl)erbium halides, and bis(cyclopentadienyl)erbium alkyls.
12. A process for creating an erbium-doped silicon layer on a substrate comprising:
(a) introducing a silicon substrate into a film-forming chamber for forming a deposition film on a substrate;
(b) introducing a flow of from 1 to 100 sccm of SiH4 into said chamber;
(c) maintaining said substrate at from 450° to 800°C;
(d) maintaining the pressure in said chamber at from 10 to 10-9 torr; and (e) leading a flow of tris(1,1,1,5,5,5- hexafluoro-2,4-pentanedionato)erbium in the gas phase into said chamber so as to form a deposition film on said substrate.
(a) introducing a silicon substrate into a film-forming chamber for forming a deposition film on a substrate;
(b) introducing a flow of from 1 to 100 sccm of SiH4 into said chamber;
(c) maintaining said substrate at from 450° to 800°C;
(d) maintaining the pressure in said chamber at from 10 to 10-9 torr; and (e) leading a flow of tris(1,1,1,5,5,5- hexafluoro-2,4-pentanedionato)erbium in the gas phase into said chamber so as to form a deposition film on said substrate.
13. A process according to claim 12 wherein said flow of SiH4 is 4 sccm, said substrate is maintained at about 650°C, said pressure is maintained at about 1.5mtorr and said flow of tris(1,1,1,5,5,5-hexafluoro-2,4-pentanedionato)erbbium is obtained by heating tris(1,1,1,5,5,5-hexafluoro-2, 4-pentanedionato)erbium at 55 to 65°C at 1.5mtorr.
14. An optically active epitaxial film comprising a semiconductor consisting of silicon, germanium, or silicon-germanium and from about 8 x 1018 to about 8 x 1019 atoms/cm3 of a rare earth element, said film being substantially free of rare earth silicide and rare earth germanide precipitates.
15. An optically active epitaxial film according to claim 14 wherein said semiconductor is silicon.
16. An optically active epitaxial film according to claim 14 wherein said semiconductor is germanium.
17. A chemical vapor deposition process for creating a rare earth-doped semiconductor layer on a substrate comprising depositing said layer by the thermal decomposition of a gaseous precursor mixture of a silane, germane or mixture thereof and a rare earth compound.
18. A process according to claim 17 wherein said rare earth-doped semiconductor layer contains said rare earth element in substantially a single phase at a concentration which is higher than the equilibrium concentration for a single phase of said rare earth in said semiconductor layer.
19. A process according to claim 17 wherein said gaseous precursor mixture additionally comprises a source of oxygen atoms.
20. A process according to claim 19 wherein said source of oxygen atoms is said rare earth compound.
21. A process according to claim 20 wherein said rare earth compound is chosen from the group consisting of hexafluoroacetylacetonates, acetylacetonates, tetramethylheptanedionates and fluorooctanedionates.
22. A process according to claim 21 wherein said rare earth is chosen from the group consisting of erbium, terbium and europium.
23. A process according to claim 17 wherein said rare earth-doped semiconductor layer is optically active and substantially free of rare earth silicide and rare earth germanide precipitates.
24. A process according to claim 19 additionally including the step of introducing a source of carbon atoms into said film forming chamber whereby said semiconductor layer comprises said semiconductor, said rare earth, oxygen and carbon.
25. A process according to claim 19 additionally including the step of introducing a source of fluorine atoms into said film forming chamber whereby said semiconductor layer comprises said semiconductor, said rare earth, oxygen and fluorine.
26. A process according to claim 19 wherein said source of oxygen atoms is a third gaseous component.
27. A process according to claim, 26 wherein said third gaseous component is nitrous oxide.
28. A process according to claim 17 wherein said substrate is heated at 450° to 800°C.
29. A process according to claim 2 additionally including the step of introducing a source of carbon atoms into said film forming chamber whereby said semiconductor layer comprises said semiconductor, erbium, oxygen and carbon.
30. A process according to claim 2 additionally including the step of introducing a source of fluorine atoms into said film forming chamber whereby said semiconductor layer comprises said semiconductor erbium, oxygen and fluorine.
31. A chemical vapor deposition process according to claim 17 for creating a rare earth-doped silicon layer on a substrate comprising depositing said layer by the thermal decomposition of a gaseous precursor mixture of a silane and a rare earth compound.
32. A process according to claim 31 wherein said rare earth-doped silicon layer contains said rare earth element in substantially single phase at a concentration which is higher than the equilibrium concentration for a single phase of said rare earth in silicon.
33. A process according to claim 31 wherein said gaseous precursor mixture additionally comprises a source of oxygen atoms.
34. A process according to claim 33 wherein said source of oxygen atoms is said rare earth compound.
35. A process according to claim 34 wherein said rare earth compound is chosen from the group consisting of hexafluoroacetylacetonates, acetylacetonates, tetramethylheptanedionates and fluorooctanedionates.
36. A process according to claim 35 wherein said rare earth is chosen from the group consisting of erbium, terbium and europium.
37. A rare earth-doped semiconductor layer comprising a semiconductor consisting of silicon, germanium, or silicon-germanium and a rare earth element in substantially a single phase at a concentration which is higher than the equilibrium concentration for a single phase of said rare earth in said semiconductor layer and wherein said layer is substantially free of rare earth silicide and rare earth germanide precipitates.
38. A layer according to claim 37 wherein said semiconductor is selected from the group consisting of silicon, germanium and mixtures thereof and said layer is substantially free of rare earth silicide and rare earth germanide precipitates.
39. A layer according to claim 37 wherein said rare earth element is selected from the group consisting of erbium, terbium and europium.
40. A rare earth doped semiconductor layer, comprising:
a layer of a silicon, germanium or mixture thereof and a high concentration of a rare earth element, said high concentration being higher than the equilibrium concentration for a single phase of said rare earth element in said semiconductor layer, said layer being substantially free of rare earth semiconductor precipitates;
said layer being formed by a chemical vapor deposition process for creating a layer on a substrate comprising depositing said layer by thermal decomposition of a gaseous precursor mixture of a silane, germane or mixture thereof and a rare earth compound.
a layer of a silicon, germanium or mixture thereof and a high concentration of a rare earth element, said high concentration being higher than the equilibrium concentration for a single phase of said rare earth element in said semiconductor layer, said layer being substantially free of rare earth semiconductor precipitates;
said layer being formed by a chemical vapor deposition process for creating a layer on a substrate comprising depositing said layer by thermal decomposition of a gaseous precursor mixture of a silane, germane or mixture thereof and a rare earth compound.
41. An epitaxial semiconductor layer according to claim 40 wherein said layer comprises from 8 x 10 18 to 8 x 10 19 atoms/cm3 of said rare earth element.
42. An epitaxial semiconductor layer according to claim 40 wherein said rare earth is selected from the group consisting of erbium, terbium and europium.
43. An epitaxial semiconductor layer according to claim 40 wherein said layer further comprises oxygen atoms, and said gaseous precursor mixture additionally comprises a source of oxygen atoms.
44. An epitaxial semiconductor layer according to claim 40 wherein said layer further comprises carbon atoms and said gaseous precursor mixture additionally comprises a source of carbon atoms.
45. An epitaxial semiconductor layer according to claim 40 wherein said layer further comprises fluorine atoms and said gaseous precursor mixture additionally comprises a source of fluorine atoms.
46. An epitaxial semiconductor layer according to claim 43, wherein said oxygen atoms are present at a concentration of about 4 x 10 19 atoms/cm3.
47. An epitaxial semiconductor layer according to claim 44, wherein said carbon atoms are present at a concentration of about 4 x 10 19 atoms/cm3.
48. An epitaxial semiconductor layer according to claim 45, wherein said fluorine atoms are present at a concentration of about 4 x 10 19 atoms/cm3.
49. An optoelectronic device comprising a substrate and an epitaxial semiconductor film adherent thereon, said film containing from about 8 x 10 18 to about 8 x 10 19 atoms/cm3 of a rare earth element and said film being substantially free of rare earth semiconductor precipitates and electrically degrading defects.
50. An optoelectronic device comprising a silicon substrate and a semiconductor film adherent thereon, said film containing from about 8 x 10 18 to about 8 x 10 19 atoms/cm3 of a rare earth element and said epitaxial film being substantially free of rare earth semiconductor precipitates.
51. An optoelectronic device comprising a silicon substrate and a epitaxial silicon film adherent thereon, said film containing from about 8 x 10 18 to about 8 x 10 19 atoms/cm3 of erbium and said epitaxial film being substantially free of erbium silicide precipitates.
52. The optoelectronic device according to claim 49, wherein said substrate comprises a single crystal silicon wafer.
53. The optoelectronic device according to claim 49, wherein said rare earth element is selected from the group consisting a erbium, terbium, and europium.
54. The optoelectronic device according to claim 49, wherein said semiconductor film comprises a semiconductor and said rare earth element in substantially a single phase at a concentration which is higher than the equilibrium concentration for a single phase of said rare earth in said semiconductor layer.
55. The optoelectronic device according to claim 54, wherein said semiconductor is selected from the group consisting of silicon, germanium, and mixtures thereof, and said film is substantially free of rare earth silicide and rare earth germanide precipitates.
56. The optoelectronic device according to claim 54, wherein said rare earth element is erbium and said film is substantially free of erbium germanide and erbium silicide precipitates.
57. The optoelectronic device according to claim 49, claim 50 or claim 51, wherein said film further comprises from about 10 17 to about 10 19 atoms/cm3 of oxygen.
58. The optoelectronic device according to claim 49, claim 50 or claim 51, wherein said film further comprises from about 10 17 to about 10 19 atoms/cm3 of fluorine.
59. The optoelectronic device according to claim 49, claim 50 or claim 51, wherein said film further comprises from about 10 17 to about 10 19 atoms/cm3 of carbon.
60. An optically active epitaxial film according to claim 16 wherein said rare earth element is erbium and said film is substantially free of erbium germanide precipitates.
61. An optically active epitaxial film according to claim 14 wherein said semiconductor is silicon-germanium .
62. An optically active epitaxial film according to claim 61 wherein said rare earth element is erbium and said film is substantially free of erbium germanide and erbium silicide precipitates.
63. An optically aetive epitaxial film according to claim 14 additionally comprising oxygen atoms.
64. An optically active epitaxial film according to claim 14 additionally comprising fluorine atoms.
65. An optically active epitaxial film according to claim 14 additionally comprising carbon atoms.
66. An optically active epitaxial film according to claim 15 comprising silicon and from about 8 x 10 18 to about 8 x 10 19 atoms/cm3 of erbium, said film being substantially free of erbium silicide precipitates.
67. A film according to claim 66 further comprising about 4 x 10 19 atoms/cm3 of oxygen.
68. An optically active epitaxial film according to claim 63, wherein said oxygen atoms are present at a concentration of about 4 x 10 19 atoms/cm3.
69. An optically active epitaxial film according to claim 64, wherein said fluorine atoms are present at a concentration of about 4 x 10 19 atoms/cm3.
70. An optically active epitaxial film according to claim 65, wherein said carbon atoms are present at a concentration of about 4 x 10 19 atoms/cm3.
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US6093246A (en) * | 1995-09-08 | 2000-07-25 | Sandia Corporation | Photonic crystal devices formed by a charged-particle beam |
US5976941A (en) * | 1997-06-06 | 1999-11-02 | The Whitaker Corporation | Ultrahigh vacuum deposition of silicon (Si-Ge) on HMIC substrates |
US6130471A (en) * | 1997-08-29 | 2000-10-10 | The Whitaker Corporation | Ballasting of high power silicon-germanium heterojunction biploar transistors |
US6040225A (en) * | 1997-08-29 | 2000-03-21 | The Whitaker Corporation | Method of fabricating polysilicon based resistors in Si-Ge heterojunction devices |
KR100377716B1 (en) * | 1998-02-25 | 2003-03-26 | 인터내셔널 비지네스 머신즈 코포레이션 | Electric pumping of rare-earth-doped silicon for optical emission |
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1992
- 1992-08-31 US US07/940,416 patent/US5322813A/en not_active Expired - Lifetime
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1993
- 1993-05-04 CA CA002095449A patent/CA2095449C/en not_active Expired - Fee Related
- 1993-07-28 JP JP5185980A patent/JPH0785467B2/en not_active Expired - Fee Related
- 1993-07-30 AT AT93480110T patent/ATE166491T1/en active
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- 1993-07-30 DE DE69318653T patent/DE69318653T2/en not_active Expired - Lifetime
- 1993-07-30 ES ES93480110T patent/ES2116426T3/en not_active Expired - Lifetime
- 1993-08-19 TW TW082106685A patent/TW229325B/zh not_active IP Right Cessation
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- 1993-08-30 KR KR1019930017032A patent/KR970008339B1/en not_active IP Right Cessation
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1994
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1995
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CN1117389C (en) | 2003-08-06 |
KR970008339B1 (en) | 1997-05-23 |
KR940004714A (en) | 1994-03-15 |
CA2095449A1 (en) | 1994-03-01 |
US5534079A (en) | 1996-07-09 |
CN1114225C (en) | 2003-07-09 |
JPH0785467B2 (en) | 1995-09-13 |
CN1054234C (en) | 2000-07-05 |
JPH06177062A (en) | 1994-06-24 |
EP0586321A2 (en) | 1994-03-09 |
EP0586321B1 (en) | 1998-05-20 |
ATE166491T1 (en) | 1998-06-15 |
DE69318653D1 (en) | 1998-06-25 |
CN1255736A (en) | 2000-06-07 |
CN1085353A (en) | 1994-04-13 |
CN1255735A (en) | 2000-06-07 |
EP0586321A3 (en) | 1996-03-27 |
MX9305267A (en) | 1994-02-28 |
ES2116426T3 (en) | 1998-07-16 |
US5322813A (en) | 1994-06-21 |
US5646425A (en) | 1997-07-08 |
DE69318653T2 (en) | 1999-02-04 |
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