Semipolar Nitrides Grown on Si(001) Offcut Substrates with 3C-SiC Buffer Layers

Abstract

The growth process of semipolar GaN(10-12) on Si(001) offcut substrates with 3C-SiC buffer layers has been investigated. From XRD analysis, the difference in the crystal orientation between GaN(10-12) and 3C-SiC(001) has been found to be around 8˚ toward the [110] direction of the 3C-SiC templates. From TEM observations, a cubic-phase AlN seed layer is found to grow on 3C-SiC(001) templates, and the swift transition from the cubic phase to a hexagonal phase leads to the stable growth of hexagonal nitrides. Using 8˚-offcut Si substrates, it is possible to obtain a mirror-like surface of GaN(10-12) using an approximately 10-nm-thick AlN seed layer, which swiftly transitions from cubic AlN to hexagonal GaN.