Theoretical study of H-P and H-B complexes in silicon

The microscopic structures of hydrogen in donor- and acceptor-doped silicon have been studied with ab initio calculations based on the density-functional theory. Some results are found to have a strong dependence on the supercell size. By using a 64-atom supercell and a large plane-wave basis set (with a 22-Ry kinetic-energy cutoff), quantitative agreements with existing experimental data have been achieved for the equilibrium geometries and vibrational properties of Si-H-P and Si-H-B systems. The investigation also predicts a low vibrational frequency for the H-wagging mode in the Si-H-B complex.