Superior Data Retention of Programmable Linear RAM (PLRAM) for Compute-in-Memory Application

Abstract

In this work, we investigate the data retention of programmable linear random-access memory (PLRAM), where the geometry and structure of memory cells have been modified to decouple the program/erase operation and gate oxide. Since PLRAM utilizes the bidirectional Fowler-Nordheim tunneling during program and erase operations through the sidewall tunneling oxide, the gate oxide does not receive the stress from the excessive program/erase cycles, resulting in a significant improvement of the data retention. Furthermore, it is confirmed that PLRAM can guarantee the stable 7-bit accuracy under high temperatures (>200°C), while a standard multi-level flash memory cell shows a significant degradation of multi-bit functionality due to the data loss and it ends up with a 4-bit accuracy in this study.