Charge retention of scaled SONOS nonvolatile memory devices at elevated temperatures

The charge retention characteristics in scaled SONGS nonvolatile memory dev ices with an effective gate oxide thickness of 94 A and a tunnel oxide of 1 5 A are investigated in a temperature range from room temperature to 175 de grees C, Electron charge decay rate is sensitive to the temperature, wherea s hole charge decay rate remains essentially constant. Based on experimenta l observations and an amphoteric trap model for nitride traps, an analytica l model for charge retention of the excess electron state is developed. Usi ng this thermal activated electron retention model, the trap distribution i n energy within the nitride film is extracted. (C) 2000 Published by Elsevi er Science Ltd. All rights reserved.