The behavior of Sn on the (100)-(2 x 1) surface was studied by means of scanning tunnelling microscopy. At temperatures below 150C, low Sn coverages formed dimer rows that were oriented perpendicularly to the underlying Si dimer rows. With increasing coverage, these rows packed into areas of 2-dimensional order and formed small regions of 2 x 2 reconstruction when the coverage was close to 0.5 of a monolayer. When substrates were annealed at temperatures above 500C, c(4 x 4) and 2 x 6 reconstruction

occurred at coverages of less than 0.5 of a monolayer, the c(4 x 8) reconstruction occurred for coverages of between 0.5 and 1, and a 1 x 5 reconstruction occurred for coverages of between 1 and 1.5 monolayers. It was found that both the c(4 x 4) and 2 x 6 phases consisted of missing Si dimer trenches and stripe-like structures which grew perpendicularly to the Si dimer rows. As the coverage increased, the c(4 x 8) reconstruction occurred when chain-like structures, consisting of buckled Sn dimers, formed on the surface between trenches. The 1 x 5 phase then grew over this c(4 x 8) layer and consisted of bright features which were thought to be associated with Sn dimers. When more than 2 monolayers were deposited and annealed, the surface underwent gross rearrangement and formed (331)-type facets.

A.A.Baski, C.F.Quate, J.Nogami: Physical Review B, 1991, 44[20], 11167-77