Physical Modeling and Analysis for Performance Enhancement of Terahertz Wave Detector based on Silicon Field-Effect Transistor

Abstract

We report the nonresonant plasmonic terahertz (THz) wave detector based on the silicon (Si) field effect transistor (FET) with a technology computer-aided design (TCAD) platform. The plasma wave behavior has been modeled by a quasi-plasma electron box as a two-dimensional electron gas (2DEG) in the channel of the FET. The incoming alternating current (AC) signal as the THz wave radiation can induce the direct-current (DC) voltage difference between the source and drain, which is called the photoresponse. For accurate analysis of the modulation and propagation of the channel electron density as the plasma wave, we have characterized the quasi-plasma 2DEG model with two key parameters, such as quasi-plasma 2DEG length (lQP) and density (NQP). By using our normalization method, lQP and NQP is defined exactly as extracting the average point of the electron density. We also investigate the performance enhancement of the plasmonic terahertz wave detector based on Si FET by scaling down the gate oxide thickness (tox), which is a significant parameter of FET-based plasmonic terahertz detector for the channel electron density modulation. According to scaling down tox, the responsivity (Rv) and noise equivalent power (NEP), which are the important performance metrics of the THz wave detector, have been enhanced. The proposed methodologies will provide the advanced physical analysis and structural design platform for developing the plasmonic terahertz detectors operating in nonresonant regime.