Total energy calculations based on density functional theory in connection with generalized gradient approximation (GGA) and norm-conserving optimized pseudopotential approximation have been used to investigate the silane chemisorption onto Si(111) and Si(100) surfaces. Firstly, the calculated relaxed surface structure of Si(100)-(2’2) has a different dangling bonds environment from that of the calculated relaxed surface structure of Si(111)-(1’1). Secondly, our calculated results indicate that SiH4 chemisorption onto both Si(100)-(2’2) and Si(111)-(1’1) surfaces are energetically favorable and they lead to the formation of SiH3 and H adsorbed on the Si=Si dimer, I.e. Si(100)-(2’2)(SiH3:H) and the surface dihydride SiH2 and 2H, I.e. Si(111)-(1’1)(SiH2:2H), respectively. Finally, the increase of dangling bond density and the absence of adatom backbond breaking are probably two of the key factors controlling the distinct increase in reaction probability for dissociative chemisorption of SiH4 onto Si(111)-(7’7) due to Si(111)-(7’7) ? Si(111)-(1’1) phase transition at surface temperature greater than 800 °C.
Journal of the Chinese Chemical Society=中國化學會會誌 47(4B), pp.887-894