AlGaN/GaN modulation-doped field-effect transistors with an Mg-doped carrier confinement layer

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 g(m), I-DS 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.