The Role of Charge Dipoles in GaN HFET Design

Abstract

Polarization induced charge dipoles are a new phenomenon in GaN-devices. Therefore a ridged quantum mechanical and an engineering model have been developed to allow for polarization effects in GaN-based heterostructures. A corresponding routine has been implemented into a commercial device simulator and applied to a variety of FET-device structures including an AlGaN double barrier device and n-channel and p-channel InGaN FET structure. The basic concept to avoid an ambipolar carrier distribution caused by the dipole field is that of doping screening of the polarization field.