MOCVD growth of cubic GaN on 3C-SiC deposited on Si (100) substrates

The growth of cubic GaN on 3C-SiC/Si(100) by metal-organic chemical vapor d eposition (MOCVD) under various growth temperatures, thicknesses of 3C-SiC, and V/III ratios was studied. The fractions of cubic and hexagonal phases in the films were estimated from the integrated x-ray diffraction intensiti es of the cubic (002) and hexagonal (1011) planes. A smooth SiC layer, a hi gh growth temperature, and a moderate V/III ratio are three key factors for the nucleation of the cubic phase and its subsequent growth. Hexagonal GaN with its c-axis perpendicular to the substrate preferentially grows at the low temperature of 750 degrees C. The inclusion of the cubic phase increas es with increasing growth temperature. The optimum growth conditions for do minant cubic GaN formation were a growth temperature of 950 degrees C, a 1. 5 mu m thick SiC layer, and a V/III ratio of 1500. With these growth condit ions, a cubic GaN layer with the cubic component of 91% was obtained.