Electrical characteristics of GaN-based metal-oxide-semiconductor (MOS) structures

Gallium nitride (GaN) has attracted considerable interest for electronic device applications at high temperature environment with high power conditions. The large lattice mismatch and the large thermal expansion coefficient difference between the GaN film and silicon substrate makes it difficult to get film of high quality and suitable for the metal-oxide-semiconductor (MOS) devices. However, deposited films can be subjected to different fabrication processes to exhibit good electrical characteristics. In this paper, we report on the fabrication and characterization of MOS capacitor based on GaN grown on silicon substrates at low growth temperatures (200 and 600 °C). The roughness, morphology, composition and crystalline quality of the GaN films were determined by atomic force microscopy (AFM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX) and X-ray diffraction (XRD) measurements. The fabricated MOS structures were characterized using capacitance-voltage (C-V) measurements.