Two-Dimensional X-Ray Diffraction And Transmission Electron Microscopy Study On The Effect Of Magnetron Sputtering Atmosphere On Gan/Sic Interface And Gallium Nitride Thin Film Crystal Structure

The growth mechanisms of high quality GaN thin films on 6H-SiC by sputtering were investigated by X-ray diffraction (XRD) and scanning transmission electron microscopy (STEM). The XRD theta-2 theta scans show that high quality (0002) oriented GaN was deposited on 6H-SiC by reactive magnetron sputtering. Pole figures obtained by 2D-XRD clarify that GaN thin films are dominated by (0002) oriented wurtzite GaN and {111} oriented zinc-blende GaN. A thin amorphous silicon oxide layer on SiC surfaces observed by STEM plays a critical role in terms of the orientation information transfer from the substrate to the GaN epilayer. The addition of H-2 into Ar and/or N-2 during sputtering can reduce the thickness of the amorphous layer. Moreover, adding 5% H-2 into Ar can facilitate a phase transformation from amorphous to crystalline in the silicon oxide layer and eliminate the unwanted {3 (3) over bar 02} orientation in the GaN thin film. Fiber texture GaN thin films can be grown by adding 10% H-2 into N-2 due to the complex reaction between H-2 and N-2. (C) 2015 AIP Publishing LLC.