Chacko Jacob

Lateral over-growth of 3C–SiC on patterned Si(1 1 1) substrates

Abstract The heteroepitaxial growth of 3C–SiC on Si and other substrates has indicated the potential for high mobility devices. However, the high density of interfacial defects (misfit dislocations, voids) as well as other defects (threading dislocations, twins, stacking faults) result in the growth of lower quality material. A suitable approach towards solving this problem is the use of selective epitaxial growth on patterned silicon substrates followed by epitaxial lateral overgrowth. The substrates used were patterned silicon substrates prepared by depositing a SiO 2 layer as the mask, followed by conventional lithographic techniques. The windows are of different shapes (square, circular, hexagonal, parallel lines) with their edges oriented mostly along the 〈1xa01xa00〉 direction. Selective growth was carried out at the substrate temperature of 1150°C using hexachlorodisilane (HCDS) and propane. Lateral overgrowth was observed in these films. The selectivity was a function of temperature. An additional factor influencing selectivity was the concentration of the precursors. Coalescence of the epilayer on the windows strongly depended on the shape of the windows. Complete coalescence of the islands was not observed on windows with square and circular shapes. However, it was observed on the hexagonal windows as the growth fronts continued to maintain their linearity as growth proceeded.