High-density single-poly electrically erasable programmable logic device for embedded nonvolatile memory applications

Abstract

A novel electrically erasable programmable logic device (EEPLD) memory cell with new program and erase operations fabricated by a standard complementary metal-oxide-semiconductor (CMOS) logic process is presented. The cell which consists of two metal-oxide-semiconductor field effect transistor (MOSFET) transistors in series is programmed by select-gate-controlled drain avalanche hot hole injection and erased by channel hot electron injection. The cell exhibits good programming and erasing characteristics along with endurance up to 105 cycles, and 1000h of data retention at 150°C. A new self-converged programming scheme is investigated for multilevel or analog storage. Without a P-well or an N-well serving as a coupling gate, the novel cell provides the smallest area size per bit reported for a single-poly nonvolatile memory. With its small cell size and full compatibility with the standard CMOS logic process, the novel EEPLD can be easily adopted in highly integrated VLSI systems. © 2005 The Japan Society of Applied Physics.