Single-Poly Embedded NVM Solution for Analog Trimming and Code Storage Applications

Abstract

We report a single-poly embedded nonvolatile memory (eNVM) solution for analog trimming and code storage applications using a 0.13-μm BCDMOS process. Each cell has its own merits and demerits, depending on structure and operation methods. For analog trimming purposes, a conventional n-well coupling Fowler-Nordheim tunneling cell with a large unit cell size of 88 μm2 is used. On the other hand, a select gate lateral coupling (SGLC) cell for code storage purposes has a much smaller unit cell size of 2.82 μm2, which is comparable to the size of SRAM. The SGLC cell is fabricated using a combination of only 1.5-V and 5-V transistor-related processes for channel hot electron injection programming. The SGLC cell exhibits a high programming speed of 100 μs and is over-erase-free, which is suitable for a NOR array structure. In addition, both cells also had a retention lifetime of more than 10 years. Thus, these cells can be fabricated to match the requirements of various eNVM applications.