Modeling Thermal Effects for 28-nm Node Fully Depleted SOI Devices Under Cryogenic Temperatures

Rapid development of space technology, high-performance computing, and quantum computing technologies elevated the significance of exploring self-heating effects in semiconductor devices operated under cryogenic temperatures. Experimental measurement techniques were proposed and applied to measure the temperature changes in the active region of the device under normal operating conditions. Different thermal theoretical models were proposed and used to simulate self-heating effects as well. Some of these thermal simulation models have limitations when applied to modeling self-heating effects in fully depleted silicon-on-insulator (FDSOI) devices operated under cryogenic temperatures. In this work, a comprehensive thermal device simulator, that couples the Boltzmann transport equation (BTE) solver (using Monte Carlo method) and the phonon energy balance equations, is presented. Temperature-and thickness-dependent thermal conductivity models and temperature dependence of the heat capacity were properly accounted for. The simulator's reliability and accuracy were validated by comparing the simulated device's electrical characteristics against available experimental data. Excellent agreement was obtained between the theory and the experiment when characterizing self-heating effects at T = 5 K and T = 300 K as a function of the input power.