[G-1] Cryo-CMOS

[G-1-02] Electron mobility of Si nMOSFETs in a nonlinear model of surface roughness scattering at cryogenic temperature

〇Kei Sumita¹, Min-Soo Kang¹, Kasidit Toprasertpong¹, Mitsuru Takenaka¹, Shinichi Takagi¹ (1. Univ. of Tokyo (Japan))

Presentation style: On-site (in-person)

https://doi.org/10.7567/SSDM.2022.G-1-02

Surface roughness (SR) scattering in MOSFETs is of great interest because it is a dominant scattering mechanism of electrons in nanosheet channels and at cryogenic temperature. Recently, the accurate nonlinear model of SR scattering has been reported. However, the validity of this nonlinear model at cryogenic temperature has been not examined yet. In this study, we report that when the mobility of the Δ4 valley is underestimated, the calculated mobility agrees very well with the experimental values, suggesting a new physical model that the Δ4 valley electrons are occupied at 4.2 K in tail states with low mobility.