Venkatraman Prabhakar

A scalable, low voltage, low cost SONOS memory technology for embedded NVM applications

A novel low cost, eNVM technology is presented which has the lowest program/erase voltage reported to date. It is based on the integration of a SONOS based NVM module into a foundry CMOS process with only 3 additional masks and no additional HV oxide. An optimized integration scheme ensures that the CMOS device parameters of the eNVM process are closely matched to baseline process. Even with the low 7.5V program/erase voltage, excellent reliability has been demonstrated meeting automotive data retention requirements and 100k cycle endurance on a 4.5Mbit flash memory macro.

Impact of Total Ionizing Dose on the Data Retention of a 65 nm SONOS-Based NOR Flash

In this paper, the impact of total ionizing dose on the data retention behavior of a silicon-oxide-nitride-oxide-silicon-based NOR flash nonvolatile memory is studied for the first time on a deep sub-micron 65-nm complementary metal-oxide semiconductor technology node. The fundamental nonvolatile single-level cell memory element utilizes uniform Fowler-Nordheim (F-N) tunneling for both program and erase operations. The data retention behavior is investigated on a 4-Mb NOR Flash-based memory array at space-level total ionizing dose (TID) exposures up to 500 krad. Excessive TID exposure reduces the program-erase window but improves the thermal emission coefficient and, hence, improves data retention.