CN101794850B

CN101794850B - Symmetrical electrodes of parallelogram GaN-based LED chip

Info

Publication number: CN101794850B
Application number: CN2010101138044A
Authority: CN
Inventors: 孙莉莉; 闫发旺; 张会肖; 王军喜; 王国宏; 曾一平; 李晋闽
Original assignee: Institute of Semiconductors of CAS
Current assignee: Shenzhen Zhouming Technology Co Ltd
Priority date: 2010-02-24
Filing date: 2010-02-24
Publication date: 2012-09-05
Anticipated expiration: 2030-02-24
Also published as: CN101794850A

Abstract

The invention discloses symmetrical electrodes of a parallelogram GaN-based LED chip, and belongs to the technical field of LED chips. The shape of the LED chip is a non-rectangular parallelogram, an N-shaped pad is positioned on one angle of the parallelogram, an N-shaped strip electrode surrounds one circle along the edges of the parallelogram from the N-shaped pad, the pad of a P-shaped electrode is positioned in the center of the parallelogram chip, the P-shaped strip electrode is first distributed along the diagonal direction corresponding to the angle where the N-shaped pad is positioned and then distributed along the edge of the parallelogram chip, and the N electrode and the P electrode are symmetrically distributed inside the LED chip. Therefore, uniform current distribution of the parallelogram LED chip is ensured, and the aims of improving the light emitting efficiency and prolonging the service life of the parallelogram LED chip are fulfilled.

Description

The symmetry electrode of parallelogram GaN-based LED chip

Technical field

The present invention relates to the led chip technical field, especially relate to a kind of symmetry electrode of parallelogram GaN-based LED chip.

Background technology

LED as lighting source have energy-conservation (when the efficient of LED reaches 150lm/W, under the equal brightness energy consumption be about incandescent lamp 1/10), advantages such as little, low-voltage of long-life (about 100,000 hours), volume, easy to control, environmental protection.These advantages of led light source; With causing Lighting Industry technology and the revolution of using, it is the same to substitute electron tube as semiconductor transistor, after the several years; With the solid-state illumination lamp of LED, replace traditional illuminating lamp gradually with having an opportunity and get into each corner as new light sources.

At present, generally adopt the epitaxial wafer of Sapphire Substrate to prepare high efficiency GaN base LED.Led chip shape and electrode shape can the appreciable impact device luminous efficiency, reliability and life-span.At first, can improve the photoelectric characteristic of device through optimizing chip form, for example; Xiamen University is in the patent of CN201266611Y at publication number; Propose to adopt triangle led chip structure to compare, can reduce the light escape taper critical angle of chip, thereby increase the side bright dipping of led chip with adopting the traditional rectangular chip structure; Effectively improve the luminous efficiency of LED device; And the parallelogram chip is compared with the triangle led chip that can increase the side bright dipping equally, is convenient to the test analysis of chip.

On the other hand; Also can improve the photoelectric characteristic of device through the optimization of electrode shape; For example; Yangzhou University is that CN201266611Y and publication number are to rectangle GaN led chip tree-like GaN base LED chip electrode and centering ring geometric pattern GaN base LED chip electrode to be provided respectively in the patent of CN201282152Y at publication number; Because the chip electrode of these two kinds of structures can make GaN base LED chip CURRENT DISTRIBUTION even, thus can reduce current gathering effect effectively, reduce device series resistance, reduce device heating inhomogeneities, improve device luminous efficiency, improve the reliability of device and the useful life of improving device.If can the optimization of chip form and the optimization of electrode shape be combined, very favourable to the photoelectric properties that improve led chip, still, do not see patent and the bibliographical information that this respect is arranged at present as yet.

Summary of the invention

The technical problem that (one) will solve

The objective of the invention is optimization with chip form and electrode shape combines and improves the luminous efficiency of LED; Promptly the electrode to Parallelogrammic LED chip is optimized design; A kind of symmetry electrode of parallelogram GaN-based LED chip is provided; So that the Parallelogrammic LED chip electric current is evenly expanded, improve the photoelectric properties of LED device.

(2) technical scheme

For achieving the above object; The invention provides a kind of symmetry electrode of parallelogram GaN-based LED chip, comprise P electrode and N electrode, its preparation method is: the GaN epitaxial wafer is carried out mesa etch; Form P type GaN table top and N type GaN groove; Growing P-type electrode on P type GaN material, preparation N type electrode in groove, wherein:

Led chip is shaped as the parallelogram of non-rectangle, and N type pad is positioned on the angle of parallelogram, and N type strip electrode sets out from N type pad and rounds along the parallelogram edge;

The pad of P type electrode is positioned at the center of parallelogram chip, and at first corresponding diagonal distributes P type strip electrode along angle, N type pad place, and then is parallel to the edge distribution of parallelogram chip;

Be symmetrically distributed at inner N electrode of led chip and P electrode, even with the CURRENT DISTRIBUTION that guarantees Parallelogrammic LED chip, thus the light extraction efficiency and the life-span of improving Parallelogrammic LED chip.

In the such scheme, this symmetry electrode transparent conductive film of can on P type GaN, growing earlier, growth P electrode on transparent conductive film then.

In the such scheme, the shape of P type electrode and N type electrode is interchangeable, and N type electrodeposition is in the groove of respective shapes.

In the such scheme, the bar number of P type electrode and N type electrode can be adjusted with the size of parallelogram chip size.

(3) beneficial effect

The symmetry electrode of this parallelogram GaN-based LED chip provided by the invention; Be symmetrically distributed at inner N electrode of led chip and P electrode; The CURRENT DISTRIBUTION that has guaranteed Parallelogrammic LED chip is even, thereby reaches the light extraction efficiency of raising Parallelogrammic LED chip and the purpose in life-span.

Description of drawings

Fig. 1 is P type, the N type distribution of electrodes structural representation of the embodiment of the invention.

1 is P type GaN table top, and 2 is N type GaN groove, and N is a N type electrode pad, and P is a P type electrode pad, and N1～N9 is a N type strip shaped electric poles, and P1～P5 is a P type strip shaped electric poles.

Embodiment

For making the object of the invention, technical scheme and advantage clearer, below in conjunction with specific embodiment, and with reference to accompanying drawing, to further explain of the present invention.

As shown in Figure 1; At first Grown GaN base epitaxial wafer on the Sapphire Substrate is carried out mesa etch, form P type GaN table top 1 and N type GaN groove 2, at the superficial growth layer of transparent conducting film of P type layer; Deposition P electrode on nesa coating, the N electro-deposition is in the groove 2 slightly wideer than its yardstick.P type electrode comprises the P type pad that is positioned at parallelogram chip center, the P1 that corresponding diagonal distributes along angle, N type pad place, the P2～P5 that is parallel to parallelogram core four edges; N type electrode mainly comprises the N type pad that is positioned at an angle of parallelogram chip, along N1～N4 that the parallelogram chip edge distributes, the N5 that corresponding diagonal distributes along angle, N type pad place; The N6 that is parallel to P4; The N7 that is parallel to P5 is parallel to the N8 of P2, is parallel to the N9 of P3.P type electrode and N type electrode are arranged in parallel each other, and distance equates between the different electrode, have increased the uniformity of CURRENT DISTRIBUTION, have improved Parallelogrammic LED chip, particularly the light extraction efficiency of high-power Parallelogrammic LED chip.The present invention also can directly directly deposit the P electrode on P type GaN surface.In addition, in the present invention, the shape of P type electrode and N type electrode can be exchanged.

Above-described specific embodiment; The object of the invention, technical scheme and beneficial effect have been carried out further explain, and institute it should be understood that the above is merely specific embodiment of the present invention; Be not limited to the present invention; All within spirit of the present invention and principle, any modification of being made, be equal to replacement, improvement etc., all should be included within protection scope of the present invention.

Claims

1. the symmetry electrode of a parallelogram GaN-based LED chip; Comprise P electrode and N electrode; Its preparation method is: the GaN epitaxial wafer is carried out mesa etch, form P type GaN table top and N type GaN groove, growing P-type electrode on P type GaN material; Preparation N type electrode in groove is characterized in that:

Led chip is shaped as the parallelogram of non-rectangle, and N type pad is positioned on the angle of parallelogram of this non-rectangle, and N type strip electrode sets out from N type pad and rounds along the edge of the parallelogram of this non-rectangle;

The pad of P type electrode is positioned at the center of the parallelogram of this non-rectangle, and at first corresponding diagonal distributes P type strip electrode along angle, N type pad place, and then is parallel to the edge distribution of the parallelogram of this non-rectangle;

Be symmetrically distributed at inner N electrode of this led chip and P electrode, even with the CURRENT DISTRIBUTION that guarantees this led chip, thus the light extraction efficiency and the life-span of improving this led chip.

2. the symmetry electrode of parallelogram GaN-based LED chip as claimed in claim 1; It is characterized in that: in this symmetry electrode; The growth course of P electrode is the transparent conductive film of on P type GaN, growing earlier, then growth P electrode on transparent conductive film.

3. the symmetry electrode of parallelogram GaN-based LED chip as claimed in claim 1 is characterized in that: the type of P described in the claim 1 electrode is replaced with N type electrode, simultaneously the type of N described in the claim 1 electrode is replaced with P type electrode.

4. the symmetry electrode of parallelogram GaN-based LED chip as claimed in claim 1, it is characterized in that: the bar number of P type electrode and N type electrode can be adjusted with the size of this led chip size.