MULTIPLE-MODE MEMORY AND METHOD FOR FORMING SAME

摘要

A multiple-mode memory (10) 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 (20, 40), and in other layers the memory cells are implemented as field-programmable re-writable memory cells (50). In this way, both re-writability and permanent data storage are provided in an inexpensive, single-chip solution. Additional types and numbers of types of memory cells can be used.