EEPROM retention performance modulation by poly Si grain size & dopant distribution

Floating gate material plays a significant role in the performance of Electrically Erasable Programmable Read-only memory (EEPROM). In this work, three types of floating gate Si materials were utilized for fabricated EEPROM cells. In-situ doped amorphous Si shows better high temperature data retention (HTDR) performance than both poly crystalline Si and amorphous Si with post-deposition implantation. Electrical, SIMS and TEM characterization indicates the mechanism responsible for this trend is a reduction in tunnel oxide P penetration leading to reduced tunnel-oxide degradation for in-situ doped amorphous Si. Therefore, charge loss through tunnel oxide during HTDR test is significantly suppressed.