beta-(Al0.17Ga0.(83))(2)O-3/Ga2O3 Delta-Doped Heterostructure MODFETs with an Ultrathin Spacer Layer and a Back-Barrier Layer: A Comprehensive Technology Computer-Aided Design Analysis

Abstract

The output characteristics of beta-(Al0.17Ga0.(83))(2)O-3/Ga2O3-based heterostructure modulation-doped field-effect transistors (MODFETs) with an ultrathin spacer layer and a back-barrier layer are fitted with experimental measurements using a Silvaco ATLAS technology computer-aided design (TCAD) simulation environment, and the calibration of the physical model and material parameters is realized. The effects of spacer layer thickness, barrier layer thickness, Si-delta doping density, and insertion of a beta-Ga2O3 cap layer on the transfer and transconductance characteristics are examined. It is found that a beta-Ga2O3 cap layer on the top of the heterostructure can increase the sheet carrier density in the heterostructure. A breakdown analysis is also carried out to reveal the effects of several layers on the off-state characteristics. A range of channel layer thicknesses from 15 to 25 nm is found to be the optimum range to avoid a high off-state leakage current and earlier breakdown voltage.