Purity and surface structure of thick 6H and 4H SiC layers grown by sublimation epitaxy

Thick epitaxial layers have been grown with high growth rates by sublimation epitaxy. The appearance of steps on the as-grown surfaces have been investigated on both 6H and 4H SiC for both the (0001) and (0001) faces. On the Si-face the surface structure for 6H and 4H SiC shows a similar appearance whereas on the C-face a slight difference in the appearance of the steps is observed as compared with the Si-face. The incorporation of impurities depending on growth parameters has been studied. High resistivity layers with smooth morphology have been grown without intentional doping. This shows that sublimation epitaxy is a suitable technique for growth of semi-insulating material with a high growth rate.