Si-doped cubic GaN grown on a Si(001) substrate with a thin flat SiC buffer layer

Abstract

Highly Si-doped cubic GaN films were grown on a Si(001) substrate coated with a 2.5-nm-thick flat 3C–SiC buffer layer. The Si doping concentration ranged from 1×1019 to 1×1021 cm−3. Upon Si doping, the initial nucleations easily coalesced, producing a flat surface with a 4×1 reconstruction and preferential growth in the [110] direction. The density of stacking faults also increased. The substitution of Ga atoms with Si atoms and the increased density of stacking faults help to relieve the compressive stress in GaN caused by the lattice mismatch of the GaN film and the substrate. GaN showed a strong photoluminescence intensity at room temperature.