화학공학소재연구정보센터
Journal of Chemical Physics, Vol.118, No.7, 3294-3299, 2003
Precursor states of atomic hydrogen on the Si(100)-(2X1) surface
Using plane wave pseudopotential density functional theory calculations we have identified for the first time precursor states for hydrogen atom chemisorption on the Si(100)-(2x1) surface. These states exist above clean, partially, and fully monohydride-adsorbed surface dimers. In all three cases the dimer bond is broken in the trapped state. A study of the energetics for atomic desorption, abstraction, chemisorption, and migration was carried out. We find that "hot" hydrogen atoms of energies up to approximately 1.3-1.9 eV can be trapped on the surface. These atoms are highly mobile, and we obtained energetics consistent with experimental data from which precursor-mediated adsorption mechanisms have been inferred. The existence of these states provides an understanding of the non-Langmuirian atomic hydrogen adsorption probability, and also underscores the importance of lattice distortions in the interactions of hydrogen with the silicon surface. (C) 2003 American Institute of Physics.