Journal of Crystal Growth, Vol.294, No.2, 260-267, 2006
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 degrees and 2 degrees off-axis 4H-SiC(0001) substrates at temperatures below 1300 degrees C, which is more than 200 degrees 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 (T-g) is reduced. For growth on low-angle (2 degrees) vicinal substrates, topographic defect generation is increasingly difficult to control at lower T-g values. However, low to moderate values of T-g 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. (c) 2006 Elsevier B.V. All rights reserved.
Keywords:crystal morphology;growth models;chemical vapor deposition;chloride vapor phase epitaxy;hot-wall epitaxy;semiconducting silicon carbide