Suitability of thin-GaN for AlGaN/GaN HEMT material and device

In this study, we report about the suitability of thin-GaN ( similar to 200 nm) for AlGaN/GaN HEMT (High Electron Mobility Transistor) material and device. These HEMT structures are grown on SiC substrate using MOVPE (Metal Organic Vapor Phase Epitaxy). The morphological, structural, and electrical characteristics of two kinds of grown HEMT structures are studied. The HEMT structures with thin-GaN epi-layer, grown by using different AlN NL (Nucleation Layer) resulted in dislocation density of thin-GaN epi-layer comparable to similar to 2.2 mu m thick GaN epi-layer used in conventional-GaN HEMT structure. X-ray Rocking Curve broadening along the symmetric (002) and skew-symmetric (102) planes for conventional-GaN/optimized thin-GaN epi-layer of HEMT structure are found to be similar to 145/135 arc-sec and - 350/310 arc-sec respectively. Material characteristics such as structural quality, surface morphology, and 2DEG (Two-Dimensional Electron Gas) properties of the optimized thin-GaN HEMT structure are comparable with conventional-GaN HEMT structure. HEMT devices are fabricated on optimized thin-GaN and conventional-GaN based HEMT structures. The important device attributes viz. drain-source saturation current at zero gate bias ( similar to 1 A.mm(-1)), transconductance ( similar to 210 mS.mm(-1)), and pinch-off voltage (similar to -5 Volt) measured from DC characteristics are found to be comparable in both the devices. The mesa leakage is significantly improved in thin-GaN compared to conventional-GaN HEMT device to similar to 10 nA.mm(-1) from - 350 nA.mm(-1). [GRAPHICS] .

Automated summary

This study investigates the suitability of thin-GaN for AlGaN/GaN HEMT material and device, and finds that it shows comparable material characteristics and device attributes to conventional-GaN HEMTs.