STM study of Si(111)1 × 1-H surfaces prepared by in situ hydrogen exposure

• Published in: Surface science 1994-02, Vol.303 (3), p.L367-L372
• Main Authors: Owman, Fredrik, Mårtensson, Per
• Format: Article
• Language: English
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(94)90772-2

We have used scanning tunneling microscopy and low-energy electron diffraction to study the preparation of hydrogen-terminated Si(111)1 × 1 surfaces by in situ atomic-hydrogen exposure of Si(111)7 × 7 surfaces. We find that exposure at sample temperatures of 350–480°C with a hydrogen dose above 1000 L results in the complete transformation of the 7 × 7 structure to the H-terminated 1 × 1 structure. The highest quality Si(111)1 × 1-H surfaces are obtained for doses of 5000 L hydrogen at a temperature around 380°C. These surfaces have less than 5% of a monolayer stacking faults, approximately 1% point-like defects, and less than 0.5% of contamination. For larger hydrogen doses the amount of stacking faults is further reduced, but the surfaces become rough due to the formation of holes in the first bulk double layer. A discussion of the temperature dependence of the removal of the stacking faults is presented as well as a discussion on the origin of the most frequently occurring point-like defects.