Influence of pulsed laser deposited hafnium oxide thin film as gate dielectric on the fabrication of Al0.1Ga0.9N/GaN MOS-HEMT

Gallium Nitride (GaN) and Aluminium doped Gallium Nitride (Al0.1Ga0.9N) have been successfully grown and optimized for the real-ization of metal oxide high electron mobility transistors (MOS-HEMTs) using the Laser MBE technique. A catalyst-free and environment -friendly Pulsed laser deposition technique were used for the growth of the Hafnium dioxide layer as gate dielectric on top of the Al0.1Ga0.9N layer. The growth of high-quality Al0.1Ga0.9N, GaN and HfO2 thin films was confirmed by X-ray diffraction (XRD), atomic force microscopy (AFM) and photoluminescence (PL) spectra. Aluminium and platinum metal were used as ohmic (source-drain) and Schottky (gate) contacts respectively. The MOS-HEMT exhibits lower gate leakage (10-9 A), high channel current (670 mA/mm) and low capacitance (13 pF) as compared to the conventional HEMT device. The fabricated MOS-HEMT device shows an ION/OFF of 1.2 ?? 106, the electron mobility of 1333 cm2 V - 1s- 1,with an interface trap density of 7 ?? 1011 cm- 2 eV -1 and cut off frequency of 144 GHz, suggesting that fabricated devices can be used in the realization of high power devices. The resulting e- mobility obtained in the present work is much higher than that of other typical GaAs and Si MOSHEMTs.