Epitaxial GaN on Si(111): Process control of SiNx interlayer formation

Abstract
The heteroepitaxialgrowth of (0001) GaNthin films directly on (111) Si by laser-molecular beam epitaxy without the formation of a Si N x interlayer at the Ga N ∕ Si interface is reported. We also find that Si N x can be formed subsequently as a result of nitrogen diffusion to the Ga N ∕ Si ( 111 ) interface. The orientation relationship of GaN on Si(111) was determined using x-ray diffraction and selected area electron diffraction. The atomic structure of the interfaces was studied by high resolution transmission electron microscopy. A Fourier filtered image of the cross-sectional Ga N ∕ Si ( 111 ) interface demonstrated domain matching epitaxy of 6:5. Distributions of N and Ga concentrations near the Ga N ∕ Si interface were determined using electron energy loss spectroscopy.