Homoepitaxy 6H and 4H SiC on nonplanar substrates

Growth by vapor phase epitaxy around stripe mesas and in trenches formed by reactive ion etch on 6H and 4H SiC substrates has been investigated. The mesas were aligned with the low index [<11(2)over bar 0>] and [<1(1)over bar 00>] directions, as well as with the high index [1,1+root 3,2+root 3,0] directions, in order to reveal and study the growth habit. It was found that a low C:Si ratio gave a smooth growth and small differences in growth rate between lattice planes. A larger C:S1 ratio gave more faceted growth, both limited by surface kinetics and surface diffusion, and the growth rate was 10% lower in the [<1(1)over bar 00>] direction and 10% higher in the [<11(2)over bar 0>] direction, than on the substrate. Growth on mesas oriented parallel to the substrate off-orientation shows clear step-flow growth, while growth on mesas oriented perpendicular to the off-orientation reveals the singular (0001) plane, where islands are observed, which might indicate Stranski-Krastanov growth. (C) 1998 American Institute of Physics.