A nonvolatile analog neural memory using floating-gate MOS transistors

Simple floating-gate transistors fabricated by a conventional double-polysilicon process show excellent programming and charge-retention characteristics. A five-transistor synapse cell achieves 8-bit resolution and at least 6-bit accuracy for analog neural computation. It occupies 67 m×73 m in a 2-m CMOS process and can retain charge accuracy for over 25 years.This research was partially supported by DARPA under Contracts MDA972-90-C-0037 and MDA972-88-C-0048 and by TRW, Inc.