(Invited) Floating Gate Type SOI-FinFET Flash Memories with Different Channel Shapes and Interpoly Dielectric Materials

Abstract

The floating gate (FG)-type silicon-on-insulator (SOI)-FinFET flash memories with triangular-fin (TF) and rectangular-fin (RF) channels and with different interpoly dielectric (IPD) materials have been successfully fabricated using (100)- and (110)-oriented SOI wafers and orientation dependent wet etching. The electrical characteristics of the fabricated FG-type SOI-FinFET flash memories including threshold voltage (Vt) variability, program/erase (P/E) speed, memory window, endurance, and data retention at room temperature and 85 oC have been comparatively investigated. It was experimentally found that the TF channel flash memory with an Al2O3-nitride-oxide (ANO) IPD layer shows a higher P/E speed, a larger memory window, and a lower-voltage operation as compared to the RF channel flash memories with the same ANO IPD layer. Such a high performance of the TF-ANO flash memory is due to the high-k effect of the Al2O3 layer and the electric field enhancement at the sharp foot edges of the TF.