Strain controlled growth of crack-free GaN with low defect density on silicon (1 1 1) substrate

We demonstrate the growth of 4.5 μm thick gallium nitride on 100 mm diameter silicon (1 1 1) substrate using metal-organic chemical vapor deposition. For strain engineering an aluminum nitride buffer and several interlayers were applied. The realized gallium nitride layer-stack is crack-free. Several characterization methods were applied to study the crystalline quality. In X-ray diffraction measurements the full width at half maximum of the (0 0 2) reflection was found to be as low as 400″, whereas the (2 0 1) reflection showed a full width at half maximum of 580″. For verification transmission electron microscopy examinations were performed to determine the structural quality. A comparison to gallium nitride, grown on sapphire, is made.