INVESTIGATIONS OF SIO2 N-GAN AND SI3N4/N-GAN INSULATOR-SEMICONDUCTOR INTERFACES WITH LOW INTERFACE STATE DENSITY/

The electrical properties of electron beam (EB) evaporated silicon dio xide (SiO2)/n-GaN, plasma enhanced chemical vapor deposited (PECVD) Si O2/n-GaN, and PECVD silicon nitride (S(i)3N(4))/n-GaN interfaces were investigated using high frequency capacitance-voltage measurements. Co mpositions of the deposited insulating layers (SiO2 and Si3N4) were an alyzed using x-ray photoelectron spectroscopy. Metal-insulator-semicon ductor structures were fabricated on the metalorganic chemical vapor d eposition grown n-type GaN layers using EB, PECVD grown SiO2 and PECVD grown Si3N4 layers. Minimum interface state density (2.5X10(11) eV(-1 ) cm(-2)) has been observed in the PECVD grown SiO2/n-GaN interface wh en it was compared with EB evaporated SiO2/n-GaN interface (5.3X10(11) eV(-1) cm(-2)) and PECVD Si3N4/n-GaN interface (6.5X10(11) eV(-1) cm( -2)). The inter face state density (N-f) depends on the composition of deposited insulating layers. (C) 1995 American Institute of Physics. [S0003-6951(98)04032-7].