High temperature and extended endurance characteristics of EEROM

This paper presents data resulting from an investigation on the endurance characteristics of EEROM cells at elevated temperatures, and on the possibility of extending the endurance of EEROM memory arrays to beyond the current spec of 10K cycles. It will first show that the intrinsic endurance limit of an oxynitride E²cell is higher at 125°C than at room temperature due to thermal detrapping of trapped electrons in the tunneling dielectric. The endurance of EEROM memory arrays will be shown to be limited by random defects. Data will be presented to demonstrate that by combining clean processing and proper screening, the endurance spec of EEROM memory arrays can be extended to beyond 100K cycles. It is projected that in the very near future the endurance spec of an EEROM memory array can reach the intrinsic endurance limit of singles E²cells, which is more than 10⁷cycles.