Delta‐Doped β‐(Al0.17Ga0.83)2O3/Ga2O3 Double‐Channel Heterostructure MODFETs

Abstract

Herein, in delta‐doped β‐(AlxGa1–x)2O3/β‐Ga2O3 heterostructures, the 2D electron gas (2DEG) density is mainly limited by the low conduction‐band offset at the heterointerface. Double‐channel heterostructures may be a candidate solution for enhancing the 2DEG density in these heterostructures. In this study, the output characteristics, transfer, transconductance, and off‐state current characteristics of delta‐doped β‐(Al0.17Ga0.83)2O3/β‐Ga2O3 double‐channel heterostructure modulation‐doped field‐effect transistors (MODFETs), including the effects of an ultrathin spacer layer and a back‐barrier layer, are numerically evaluated. The electrical characteristics of the proposed double‐channel heterostructure MODFET are compared with those of a single‐channel heterostructure MODFET. The proposed double‐channel heterostructure MODFET shows a maximum drain current of 133.7 mA mm−1 and a g m peak of 40 mS mm−1, which are higher than those in the single‐channel case. The calculated threshold voltage is −3.45 V. The dependence of the Si δ‐doping density in the second barrier and channel layer thickness on the electrical characteristics of the proposed device is evaluated and discussed. A β‐(Al0.17Ga0.83)2O3/β‐Ga2O3 superlattice back‐barrier structure is also implemented in delta‐doped β‐Ga2O3‐based heterostructure MODFETs to improve their off‐state characteristics for the first time.