GROWTH OF 3C-SIC ON ON-AXIS SI(100) SUBSTRATES BY CHEMICAL-VAPOR-DEPOSITION

3C-SiC has been epitaxially grown by chemical vapor deposition on on-a xis Si(100) substrates in a temperature regime between 900 and 1300 de grees C. The growth process took place in a hot-wall reactor using the silane-propane-hydrogen system. The film quality of the grown layers has been examined by X-ray diffraction (XRD), transmission electron mi croscopy (TEM), and photoluminescence (PL) measurement techniques. The results from XRD and TEM are correlated and discussed in terms of gro wth processes and crystal imperfections. Films grown at 900 degrees C displayed a columnar structure in cross-sectional TEM. Higher growth t emperatures provided better material, however, voids in the Si substra te at the interface to the SiC film became large at temperatures aroun d 1300 degrees C. The presence of these voids resulted in an inhomogen eous residual strain state in the films after growth and cooling from the deposition temperature due to thermal mismatch to the substrate wh ich may explain the significant broadening of the 002 SiC XRD peak. Op timum epitaxial film quality was obtained at growth temperatures in th e range of 1200 to 1250 degrees C. The XRD full width at half maximum (FWHM) of the 002 SiC peak from these films was as low as 0.056 degree s 2 theta. PL measurements on these films also gave evidence of high q uality material based on the appearances of the nitrogen bound exciton lines with a FWHM of 2.6 meV. PL measurements were performed on the S i substrate before and after growth of the epitaxial film. Very distin ct dislocation-related luminescence from the Si substrate appeared aft er growth. The intensity of these PL lines is related to the thickness of the 3C epilayer.