AlGaN/GaN Modulation-Doped Field-Effect Transistors with An Mg-doped Carrier Confinement Layer

Abstract

AlGaN/GaN modulation-doped field-effect transistors (MODFETs) with and without the Mg-doped semi-insulating carrier confinement layer were prepared and a detailed study on the electrical properties of these samples was performed. The addition of the Mg-doped semi-insulating carrier confinement layer resulted in the degradation of crystal quality. Thus, higher values of gm, IDS and the gate voltage swing are achieved by conventional MODFETs. The source-to-drain (S–D) leakage current of conventional MODFETs was also higher, since carriers could flow through the thick unintentionally doped GaN layer. However, the S–D leakage current was reduced from 50 mA/mm to 6 mA/mm with the insertion of the Mg-doped semi-insulating carrier confinement layer.