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

Abstract

High-quality SiO 2 was successfully deposited onto GaN by photo-chemicalvapor deposition (photo-CVD) using a D 2 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-m gate, it was found that the saturated I ds , maximum g m , and gate-voltage swing (GVS) of the fabricated nitride-based MOSHFET were 512 mA/mm, 90.7 mS/mm, and 6 V, respectively.

High transconductance AlGaN/GaN MOSHFETs with photo-CVD gate oxide

“…The growth rate and refractive index of photo-CVD 0.3 0.4 0.5 0.6 0.7 0.8 0.9 0 SiO 2 grown at 300 • C and 0.9 Torr were calculated to be 3.3 nm min −1 and very close to those of the thermally grown SiO 2 layer prepared on top of Si substrates, respectively. The detailed chemical and physical analysis of our photo-SiO 2 was characterized (by XPS, AFM, FTIR and AES) and published elsewhere [12,[15][16][17]. C-V characteristics of the Al/photo-SiO 2 /GaN MIS capacitors for SiO 2 grown at different temperatures and 0.9 Torr are shown in figure 3.…”

“…The fabricated AlGaN/GaN MOSHFET exhibits a gate leakage current density of 8.7×10 −8 A cm −2 at 4 MV cm −1 and breakdown field 5 MV cm −1 , respectively [15][16][17]. Figure 4 shows drain current as a function of drain voltage (i.e.…”