Epitaxial growth of 4H–SiC at low temperatures using CH3Cl carbon gas precursor: Growth rate, surface morphology, and influence of gas phase nucleation

This paper explores homoepitaxial growth of 4H–SiC on 8° and 2° off-axis 4H–SiC(0 0 0 1) substrates at temperatures below 1300 °C, which is more than 200 °C lower than in conventional state-of-the-art SiC epitaxial growth. In this work, the growth at reduced temperatures is enabled by using halo-carbon growth precursor chloromethane. The growth rate is strongly influenced by Si cluster nucleation in the gas phase. In addition, the condensation of silicon vapor results in decrease of the silicon-to-carbon (Si/C) ratio above the growth surface. The epilayer morphology becomes strongly dependent on the Si/C ratio when the growth temperature (Tg) is reduced. For growth on low-angle (2°) vicinal substrates, topographic defect generation is increasingly difficult to control at lower Tg values. However, low to moderate values of Tg in combination with a beneficial influence of chlorine-containing products of halo-carbon decomposition largely overcome the step-bunching problem of epitaxial growth on low-angle vicinal substrates.