Effect of Low-Temperature on Endurance Characteristics of SONOS Memory

Abstract

The endurance characteristics of SONOS nonvolatile memory are investigated in a temperature range from -40°C to 85°C. The erase/program speed is sensitive to the temperature. Low-temperature severely degrades the performance of the SONOS due to its slower program/erase speed and smaller initial voltage. The critical effect is the insufficient Vte in the low-temperature. In this paper, various process improvements and operational optimizations have been proposed to improve the Vte. The experimental results clearly prove that longer Erase/Program(E/P) time and higher voltage can increase the memory window. Smaller channel implant dose and Idac can effectively trade off the program Vtp and erase Vte. Finally, the SONOS memory can be successfully used in the industry application with good reliability and high speed performance.