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.
The possibilities of commercial SPICE are expanded in the new field—space environment electronics design. For this purpose, the set of BJT and MOSFET models with account for radiation influence is included into commercial SPICE device library. The characteristics of devices and circuits subjected to space radiation exposure (gamma-rays, protons, neutrons, electrons, heavy ions) are presented and examined with emphasis on application for radiation hardened electronics systems.
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.