Normally-Off β-(Al_xGa_1-x)₂O₃/Ga₂O₃ Modulation-Doped Field-Effect Transistors With p-GaN Gate: Proposal and Investigation

Abstract

A novel <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\beta $ </tex-math></inline-formula> -(AlxGa1-x)2O3/gallium oxide (Ga2O3) modulation-doped field-effect transistor (MODFET) with p-GaN gate is proposed and investigated for the first time. TCAD device simulator calibrated with experimental results is used to develop the physical insight of device operation and to evaluate the proposed device’s performance. Besides normally- OFF operation, the proposed MODFET also shows a higher driving capability and lower ON-resistance compared to conventional Ga2O3-MODFETs of similar device dimensions. The effect of individual device parameters on the electrical characteristics of the proposed device is also investigated in detail. Besides, an analytical model is formulated to estimate the threshold voltage of these normally- OFF devices. This model is rigorously validated with numerical results for a wide range of device parameters.