Analytical charge control model for AlGaN/GaN MIS-HFETs includingan undepleted barrier layer
括非耗尽势垒层的AlGaN/GaN MIS-HFET电荷控制解析模型

An analytical charge control model considering the insulator/AlGaN interface charge and undepleted AlGaN barrier layer is presented for AlGaN/GaN metal–insulator–semiconductor heterostructure field effect transistors (MIS-HFETs) over the entire operation range of gate voltage. The whole process of charge control is analyzed in detail and partitioned into four regions: I—full depletion, II—partial depletion, III—neutral region and IV—electron accumulation at the insulator/AlGaN interface. The results show that two-dimensional electron gas (2DEG) saturates at the boundary of region II/III and the gate voltage should not exceed the 2DEG saturation voltage in order to keep the channel in control. In addition, the span of region II accounts for about 50% of the range of gate voltage before 2DEG saturates. The good agreement of the calculated transfer characteristic with the measured data confirms the validity of the proposed model.