Density functional study of silane adsorption onto Si(100) surface

Total energy pseudopotential calculations based on norm-conserving optimized pseudopotential and density functional theory (DFT) with generalized gradient approximation (GGA) have been used to study the possible pathway and corresponding energy barrier for the initial dissociative adsorption of silane (SiH₄) onto Si(100)-(2×2) surface leading to the formation of SiH₃ and H adsorbed on Si(100)-(2×2) i.e. Si(100)-(2×2)(SiH₃:H). Our calculated results found that the formation of Si(100)-(2×2)(SiH₃:H) after the SiH₄ initial adsorption onto Si(100)-(2×2) surface is energetically favorable. Also the energy barrier, which is calculated to be around 0.72 eV (GGA), occurs due to the elongation of Si–H within SiH₄ accompanying the unbuckling of the buckled Si=Si dimer on Si(100)-(2×2) surface. Finally, the reactive sticking coefficient for SiH₄ on Si(100)-(2×2) is calculated to be around 3×10⁻⁶.