Cryogenic Characterization and Analysis of Nanoscale SOI FETs Using a Virtual Source Model

Abstract

This article reports the temperature-dependent characterization and analysis of quasi-ballistic transport in fully depleted silicon-on-insulator (FD-SOI) metal-oxide-semiconductor field-effect-transistors (MOSFETs) from a 22-nm commercial CMOS technology. Measurements of current–voltage ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${I}$ </tex-math></inline-formula> – <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${V}$ </tex-math></inline-formula> ) characteristics for temperatures ranging from 10 up to 300 K are presented in this article. Key electrical parameters are extracted as a function of temperature, including threshold voltage, subthreshold swing, ON-state current, series resistance, mobility, mean free path, and ballistic ratio. An experimentally validated virtual source modeling approach that incorporates back-gate biasing is presented in this article for temperatures down to 10 K. A comparison with bulk devices reveals less reduction in ballisticity at low temperatures and is attributed to a smaller contribution from ionized impurity scattering due to lower doping in the fully depleted (FD) channel.