Selective growth of 4H-SIC on 4H-SiC substrates using a high temperature mask

Selective growth of SiC on SiC substrate was demonstrated in a chemical vapor deposition (CVD) reactor using a new high temperature mask. Bulk 4H-SiC with 8degrees miscut (0001) Si-face wafers were coated with the high temperature mask and patterned using standard photolithography. The pattern consisted of window stripes as spokes of a wheel. Epitaxial growth of SiC was carried out in a conventional, horizontal, rf-heated cold wall reactor at temperatures in the range 1450-1550degreesC. When the window stripes are oriented along <1120> miscut direction, the growth on the exposed area followed the substrate orientation, and the top surface was smooth and specular. However, when the window stripes are aligned along <1100> direction (perpendicular to the miscut direction), the growth on the window stripes developed (0001) facets on the surface. Epitaxial lateral overgrowth over the mask was also studied by cross sectional scanning electron microscopy (SEM). It was found that the extent of lateral growth varied with the stripe orientation. Effects of growth temperature as well as silane flows on the selective growth were also studied. Higher temperature or lower silane flow results in the etching of exposed SiC instead of growth. The etched surfaces developed orientation dependent facets similar to the growth. Importantly, the mask could be easily removed after the growth.