TCAD Modeling for Si–Ge HBT THz Detectors

Abstract

Terahertz (THz) response of transistor and integrated circuit yields important information about device parameters and has been used for distinguishing between working and defective transistors and circuits. Using a technology computer-aided design (TCAD) model for Si-Ge heterojunction bipolar transistors (HBTs), we simulate the current-voltage characteristics and the response to sub-THz (300 GHz) radiation. Applying different mixed mode schemes in TCAD, we simulated the dynamic range of the THz response for Si-Ge HBTs and showed that it is comparable with that of the field effect transistor-based THz (TeraFET) detectors. The HBT response to the variations of the detector design parameters are investigated at different frequencies with the harmonic balance simulation in TCAD. These results are useful for the physical design and optimization for the HBT THz detectors and for the identification of faulty Si-Ge HBT and Si bipolar (Bi)CMOS circuits by using sub-THz or THz scanning.