Nearly Ideal Subthreshold Swing and Delay Reduction of Stacked Nanosheets Using Ultrathin Bodies
Journal
Digest of Technical Papers - Symposium on VLSI Technology
Journal Volume
2022-June
ISBN
9781665497725
Date Issued
2022-01-01
Author(s)
Tsai, Chung En
Cheng, Chun Yi
Huang, Bo Wei
Lin, Hsin Cheng
Chou, Tao
Tu, Chien Te
Liu, Yi Chun
Jan, Sun Rong
Chen, Yu Rui
Hsieh, Wan Hsuan
Chiu, Kung Ying
Chueh, Shee Jier
Abstract
Ultrathin body exhibits excellent immunity to subthreshold swing (SS) degradation by doping and Dit, approaching the ideal SS of 60mV/dec. Highly stacked Ge0.9Sn0.1 ultrathin bodies down to 2nm are fabricated to achieve record low SS of 64mV/dec and record high ION/IOFF of 1.6x107 among GeSn pGAAFETs. Superior inter-channel uniformity and good crystallinity of the 8 stacked Ge0.9Sn0.1 ultrathin bodies are demonstrated by the co-optimization of CVD epitaxy (50 layers) and highly selective isotropic dry etching with low thermal budget (=400). Moreover, the improvement of total gate capacitance and intrinsic gate delay using the ultrathin body is confirmed by TCAD due to the reduced stack height.
Type
conference paper