A multiple-mode memory includes a three-dimensional array of word lines, bit lines and memory cells. The memory cells are arranged in multiple vertically stacked layers. In some layers the memory cells are implemented as field-programmable write-once memory cells, and in other layers the memory cells...http://www.google.es/patents/US6839262?utm_source=gb-gplus-sharePatente US6839262 - Multiple-mode memory and method for forming same
