Compact Modeling of 0.35 micron SOI CMOS Technology Node for 4 K DC Operation using Verilog-A

TL;DR

This paper presents a Verilog-A based compact model for 0.35 micron SOI CMOS transistors operating at 4 K, accurately capturing low-temperature effects and nonlinear device behaviors for circuit simulation.

Contribution

It introduces a Verilog-A modification to BSIM models that incorporates nonlinear length, width, and bias effects, enabling accurate 4 K DC behavior modeling across device variations.

Findings

Accurately reproduces 4 K DC characteristics of SOI MOSFETs

Models nonlinear effects like current kinks at 4 K

Provides a unified model for various device geometries

Abstract

Compact modeling of MOSFETs from a 0.35 micron SOI technology node operating at 4 K is presented. The Verilog-A language is used to modify device equations for BSIM models and more accurately reproduce measured DC behavior, which is not possible with the standard BSIM model set. The Verilog-A approach also allows the embedding of nonlinear length, width and bias effects into BSIM calculated curves beyond those that can be achieved by the use of different BSIM parameter sets. Nonlinear dependences are necessary to capture effects particular to 4 K behavior, such as current kinks. The 4 K DC behavior is reproduced well by the compact model and the model seamlessly evolves during simulation of circuits and systems as the simulator encounters SOI MOSFETs with different lengths and widths. The incorporation of various length/width and bias dependent effects into one Verilog-A / BSIM4 library, therefore, produces one model for all sets of devices for this technology node.