Phase transitions on clean Si(110) surfaces

The properties of the structure of clean Si(110) surfaces have been investigated by LEED. The phase transitions between surface structures Si(110)?(4 × 5), Si(110)?(2 × 1) and Si(110)(5 × 1) take place at about 600 and 750°C. The time of reconstruction from the high temperature phase to the low temperature phase may exceed the time of the sample cooling. That explains why the Si(110)?(2 × 1) and the Si(110)?(5 × 1) superstructures may be seen at room temperature. Surface defects favour the retaining of high temperature phases on the surface at room temperature. The transition from the Si(110)?(5 × 1) structure to the Si(110)?(2× 1) structure and conversely in the temperature range of 720–750°C apparently occurs through formation of the intermediate structures Si(110)?(7 × 1) and Si(110)?(9 × 1). The models are given of superstructures observed by LEED.