Influence of the screening effect on passivation of p-type silicon by hydrogen

Passivation of p-Si by hydrogen through its diffusion was simulated by solving diffusion-kinetic equations with allowance made for hydrogen-acceptor-pair formation, internal electric field, and the screening effect. Screening of hydrogen and acceptor ions by free carriers leads to a decrease in the radius of interaction between the ions and to the weakening of the concentration dependence of hydrogen diffusivity in heavily doped Si. At a binding energy of the pairs of 0.70-0.79 eV, calculated and experimental concentration profiles of holes and the hydrogen-acceptor pairs are in agreement over a wide range of boron concentrations, from 4 x 10(14) to 1.2 x 10(20) cm(-3). The radius of the Coulomb interaction of hydrogen and boron ions is 35 Angstrom in lightly doped Si and decreases as the dopant concentration increases. (C) 2002 MAIK "Nauka / Interperiodica".