Structures of 6H-SiC Surfaces
نویسندگان
چکیده
We have systematically studied reconstructions of the 6H SiC(0001) and (0007) surface under both Si rich and C rich condition using field ion-scanning tunneling microscopy (FI-STM). The sample was cleaned by in situ Si beam etching at 900-1000 'C. The Si rich and C rich phases were produced by annealing the sample in a Si flm and C2HZ, respectively. On the (0001) surface, the as-cleaned surface showed (43x43) reconstruction. With increasing Si concentration, (2x2), (243x643), (3x3), and (7x7) reconstructions were observed. Reaction of the Si rich phases with C2H2 molecule at 1050 "C resulted in the formation of C rich surface, which exhibited (2x2)/(6~6) reconstruction. On the (0001) surface, (243x243) reconstruction was observed after cleaning. Under Si rich condition, (2x21, (3x3, and (7x7) reconstructions were observed. Annealing the surface in C2H2 beam at 1050 "C led to C rich phase with (1x1) structure. Structure model for (43x43) and (243x243) reconstruction are proposed, and possible applications of using the surface reconstruction to selectively grow the polytype SIC is discussed.
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