Evolution of two-dimensional structure phase transitions (3 x 1) -> (2 x 1) and (1 x 1) -> (2 x 1) on hydrogen-terminated Si(100) surface

Abstract

On the Si(100) surface, monohydride dimers (H-Si-Si-H or M-M) and dihydride (H-Si-H or D) species can form an ordered mixture with (3 x 1), (1 x 1) and (2 x 1) phases. Thermal annealing at elevated temperatures causes both the (3 x 1) and (1 x 1) domains to transform to the (2 x 1) monohydride phase. We utilize scanning tunneling microscopy to observe these two-dimensional structure phase transitions on the atomic scale. The results show that the coverage of the (3 x 1) and (1 x 1) domains decays linearly with a common half-life time of similar to 9.8 It at 570 K. In good agreement with a previous report, this finding suggests that the two different transitions are governed by the same reaction mechanism, i.e., the dihydride-pair recombination mechanism.