Growth of 3C [sbnd]SiC on on-axis Si(100) substrates by chemical vapor deposition

Abstract

3C SiC has been epitaxially grown by chemical vapor deposition on on-axis Si(100) substrates in a temperature regime between 900 and 1300°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 microscopy (TEM), and photoluminescence (PL) measurement techniques. The results from XRD and TEM are correlated and discussed in terms of growth processes and crystal imperfections. Films grown at 900°C displayed a columnar structure in cross-sectional TEM. Higher growth temperatures provided better material, however, voids in the Si substrate at the interface to the SiC film became large at temperatures around 1300°C. The presence of these voids resulted in an inhomogeneous residual strain state in the films after growth and cooling from the deposition temperature due to thermal mismatch to the substrate which may explain the significant broadening of the 002 SiC XRD peak. Optimum epitaxial film quality was obtained at growth temperatures in the range of 1200 to 1250°C. The XRD full width at half maximum (FWHM) of the 002 SiC peak from these films was as low as 0.056° 2θ. PL measurements on these films also gave evidence of high quality material based on the appearances of the nitrogen bound exciton lines with a FWHM of 2.6 meV. PL measurements were performed on the Si substrate before and after growth of the epitaxial film. Very distinct dislocation-related luminescence from the Si substrate appeared after growth. The intensity of these PL lines is related to the thickness of the 3C epilayer.