An electro-thermal modeling of modern SiGe and Si bipolar transistor structures using TCAD Sentaurus Synopsys has been carried out. It has been shown that for SiGe heterojunction bipolar transistors, operating at high current density, the internal temperature is higher than for identical Si transistors. As a result a stronger degradation of the device parameters and electrical characteristics is observed.
The effects of proton irradiation on SiGe heterojunction bipolar transistor (HBT) are investigated using Synopsys/ISE TCAD tool. To account for the impact of proton irradiation models for carrier lifetime degradation under irradiation are included in the program. The results of modeling the impact of protons of different energies are presented. For SiGe HBT increase in the base current for low-energy protons is more intense than for high-energy protons. We also present the simulation results of SiGe HBT dc and ac performance after proton exposure. The simulation results are in good agreement with experimental data.
For the correct accounting of joint effects of radiation and temperature on characteristics of MOSFETs with the help of TCAD system the nonlinear correction coefficient which considers change of concentration of traps from temperature is entered into model of traps volume density in oxide.
A special RAD-THERM version of TCAD subsystem based on Sentaurus Synopsys platform taking into account different types of irradiation (gamma-rays, neutrons, electrons, protons, single events) and external/internal heating effects was developed and validated to forecast the results of natural experiments, and help the designer on with reliability guarantee. The radiation- and temperature-induced faults were modeled and simulated for Si/SiGe BJTs/HBTs and bulk/SOI MOSFETs as BiCMOS LSI’s components. The causes of device parameter degradation were discussed.