Improved insulator/semiconductor interfaces in Al2O3/AlGaN/GaN structures by AlGaN layer regrowth

We investigated the effect of AlGaN regrown layer on the device characteristics of Al
2
O
3
/AlGaN/GaN metal-oxide-semiconductor high-electron-mobility transistors (MOS-HEMTs). From capacitance-voltage (C-V) investigations, it was confirmed that the quality of the Al
2
O
3
/AlGaN interfaces are improved by AlGaN regrowth as evidenced by negative shift of threshold voltage and the appearance of a second step in the C-V profile. Consequently, enhancement of transfer characteristic curves in terms of increased linearity and drain current density was also observed.