PERIODIC FACETING OF A SI(113) SURFACE MISCUT TOWARDS [1(1)OVER-BAR-0]

The equilibrium morphology of a Si(113) surface miscut by a polar angl e of 1.8 degrees away from the (113) orientation along an azimuth with in 3.5 degrees of the [1 (1) over bar 0] direction has been characteri zed by X-ray scattering for temperatures between 900 and 1450 K. Above 1215 K, a uniformly stepped surface is found. Between 1075 and 1215 K , the surface phase-separates into two coexisting phases of different polar and azimuthal orientations. With decreasing temperature, the pha se with the smaller polar angle approaches the (113) orientation, whil e the other phase exhibits an increasingly large polar angle (up to 9 degrees). The two coexisting phases form a periodic groove structure w ith periodicity ranging from 740 to 940 Angstrom, depending on the tem perature. Below 1075 K, the phase with the larger polar angle further phase-separates into two phases of different azimuth (+/- 17 degrees), resulting in coexistence among three distinct phases. The three coexi sting phases form a quasi-periodic array of pyramids. (C) 1998 Elsevie r Science B.V. All rights reserved.