AlGaN/GaN metal-oxide semiconductor heterostructure field-effect transistor with photo-chemical-vapor deposition SiO2 gate oxide

Abstract

High-quality SiO2 was successfully deposited onto GaN by photo-chemicalvapor deposition (photo-CVD) using a D2 lamp as the excitation source. The AlGaN/GaN metal-oxide semiconductor, heterostructure field-effect transistors (MOSHFETs) were also fabricated with photo-CVD oxide as the insulating layer. Compared with AlGaN/GaN metal-semiconductor HFETs (MESHFETs) with similar structure, we found that we could reduce the gate-leakage current by more than four orders of magnitude by inserting the photo-CVD oxide layer in between the AlGaN/GaN and the gate metal. With a 2-µm gate, it was found that the saturated Ids, maximum gm, and gate-voltage swing (GVS) of the fabricated nitride-based MOSHFET were 512 mA/mm, 90.7 mS/mm, and 6 V, respectively.