Oxygen adsorption was in situ observed by second harmonic generation (SHG) on both clean and hydrogen-preadsorbed Si(111)7 × 7. The sticking probability of molecular oxygen was decreased by monohydride formation, although it was not a completely passivating surface. This is a different effect of monohydride from that on Si(111)1 × 1 for passivation. Hydrogen adsorption at room temperature leading to both monohydride and polyhydride formation showed two different stages of sticking probability, with increasing exposure for hydrogen preadsorption, sticking probability was furthermore decreased with oxygen adsorption. This is expected due to the formation of polyhydride species on Si(111)7 × 7 which was found to be necessary for passivating reconstructed Si(111)7 × 7.
ASJC Scopus subject areas
- Surfaces, Coatings and Films