The electrical properties of electron beam (EB) evaporated silicon dioxide (SiO2)/n-GaN, plasma enhanced chemical vapor deposited (PECVD) SiO2/n-GaN, and PECVD silicon nitride (Si3N4)/n-GaN interfaces were investigated using high frequency capacitance-voltage measurements. Compositions of the deposited insulating layers (SiO2 and Si3N4) were analyzed using x-ray photoelectron spectroscopy. Metal-insulator-semiconductor structures were fabricated on the metalorganic chemical vapor deposition grown n-type GaN layers using EB, PECVD grown SiO2 and PECVD grown Si3N4 layers. Minimum interface state density (2.5×1011eV-1cm-2) has been observed in the PECVD grown SiO2/n-GaN interface when it was compared with EB evaporated SiO2/n-GaN interface (5.3×1011eV-1cm-2) and PECVD Si3N4/n-GaN interface (6.5×1011eV-1cm-2). The interface state density (Nf) depends on the composition of deposited insulating layers.
ASJC Scopus subject areas