Development of a high-growth rate 3C-SiC on Si CVD process
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0911-B08-01
Development of a high-growth rate 3C-SiC on Si CVD process M. Reyes1,2, Y. Shishkin1, S. Harvey1, and S. E. Saddow1 1 Electrical Engineering, University of South Florida, Tampa, FL, 33620 2 Chemical Engineering, University of South Florida, Tampa, FL, 33620 Abstract Growth rates from 10 to 38 µm/h were achieved for heteroepitaxial 3C-SiC on Si (100) substrates by using the propane-silane-hydrogen gas chemistry with HCl as a growth additive. A lowpressure horizontal hot-wall CVD reactor was employed to perform the deposition. The growth rate dependences on silane mole fraction, the process pressure and the growth time were determined experimentally. The growth rate dependence on silane mole fraction was found to follow a linear relationship. The 3C-SiC films were characterized by Normaski Optical Microscopy, Scanning Electron Microscopy, Fourier Transform Infrared Spectroscopy, Atomic Force Microscopy and X-ray Diffraction. The X-ray rocking curve taken on the (002) diffraction plane displayed a FWHM of 360 arcsec which indicates that the films are monocrystalline. Introduction Silicon carbide, specifically 3C-SiC, is a candidate material for high-temperature and power applications due to its outstanding physical and chemical properties, especially when compared to silicon. 3C-SiC is the only polytype that can be hetero-epitaxially grown on Si substrates, offering the advantage of a cost effective substrate. One of the most successful methods to grow 3C-SiC is by chemical vapor deposition (CVD). The standard precursor chemistry typically used is the silane-propane-hydrogen gas system. Although extensive work has been performed for decades since the early 1980’s [1], there is still a lack of good quality 3C-SiC on Si epitaxial material. While growth rates up to 40 µm/h on undulant Si (100) substrates by cold-wall CVD have been reported to produce ‘bulk-like’ substrates, defects originating from the undulant substrate persist [2]. More relevant for device manufacturing were studies performed using hot-wall CVD, which resulted in growth rates up to 13 µm/h [3-7]. It has been suggested that HCl addition to the silane/propane chemistry helps to enhance both the growth rate and the surface morphology by decreasing the concentration of Si clusters in the gas phase [8-10]. It has also been proposed that HCl improves the epitaxial film quality by etching areas of high surface energy during the deposition process [9-10]. Progress made by incorporation of HCl has been shown to significantly increase growth rates in 4H-SiC epitaxy [10-11]. For this reason attention has been focused on exploring chlorinated precursor chemistries, HCl additive included. In this work, we investigate the hetero-epitaxial growth of 3C-SiC on planar Si (100) substrates using the H2/C3H8/SiH4/HCl gas chemistry system. The film surface morphology and structural quality of the layers grown are analyzed. Experimental A low-pressure horizontal hot-wall CVD reactor was employed to carry out the deposition experiments on n-type Si (001) substrat
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