Observation of a Current Plateau in the Transfer Characteristics of InGaN/AlGaN/AlN/GaN Heterojunction Field Effect Transistors

Direct?current transfer characteristics of (InGaN)/AlGaN/AlN/GaN heterojunction field effect transistors (HFETs) are presented. A drain current plateau (I_DS=32.0 mA/mm) for V_GS swept from +0.7 V to -0.6 V is present in the transfer characteristics of InGaN/AlGaN/AlN/GaN HFETs. The theoretical calculation shows the coexistence of two-dimensional electron gas (2DEG) and two-dimensional hole gas (2DHG) in InGaN/AlGaN/AlN/GaN heterostructures, and the screening effect of 2DHG to the 2DEG in the conduction channel can explain this current plateau. Moreover, the current plateau shows the time-dependent behavior when I_DS–V_GS scans repeated are conducted. The obtained insight provides indication for the design in the fabrication of GaN-based super HFETs.