(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 (V t ) variability, program/erase (P/E) speed, memory window, endurance, and data retention at room temperature and 85 o C have been comparatively investigated. It was experimentally found that the TF channel flash memory with an Al 2 O 3 -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 Al 2 O 3 layer and the electric field enhancement at the sharp foot edges of the TF.

Fabrication and Characterization of p-Channel Charge Trapping Type FOI-FinFET Memory with MAHAS Structure

“…Thus, the scaled planar NOR-type flash memories with gate length (L g ) smaller than 100 nm are very difficult to fabricate. [1][2][3][4] On the other hand, three-dimensional (3D) channel devices, such as fin field-effect transistors (FinFET) or fin-channel tri-gate (TG) device provide excellent SCE immunity thanks to the strong electrostatic controllability of the multiple gates. 5 Moreover, threshold voltage (V th ) variability in the FinFET or TG devices is much smaller than that in the conventional bulk planar MOSFETs because V th variation induced by the random dopant fluctuation (RDF) is negligible in FinFET or TG devices owing to the undoped fin-channels.…”