Regular step formation on concave-shaped surfaces on 6H–SiC(0001)

Step formation on hydrogen-etched 6H-SiC{0001} surfaces

“…We discuss in this section the underlying mechanisms behind these phenomena. Prior work has focused primarily on the Si-face, and our experimental results are generally in good accordance with those works [4][5][6][7][8][9][10][11]. The Cface has been less well explored, with our observations providing significant new insight into that surface.…”

“…Following other authors, we conclude that these step directions have the lowest surface energy among all directions in the (0001) basal plane, or in other words, the H-etching is slowest in these directions [7,8,9]. The observed step height from Fig.…”

“…For vicinal surfaces that are miscut towards the < 00 1 1 > direction, faceting is observed on Si-face surfaces whereas the C-face shows almost no faceting. The Si-face results extend over a much larger angular range and show significantly different spatial periods than in previous work [7,8], whereas for the H-etched miscut C-face there are no prior reports that we are aware of. The differences that we observe between the Si-face and C-face, full unit-cell steps and faceting in the former but not the latter, are interpreted in terms of differences in the etch rates of the various types of steps on the two faces.…”

“…High temperature etching in gaseous environments of H 2 [2,4,5,6,7,8] or mixed H 2 and HCl [9,10,11] removes surface scratches effectively and generates atomically smooth surfaces.…”

“…Step bunching and ordered step-terrace arrays are observed on etched surfaces and have been explained on the basis of differing etch rates for various types of steps [7,8,9] or by invoking a model of elastic interactions between steps [11].…”