Absence of oxygen diffusion during hydrogen passivation of shallow-acceptor impurities in single-crystal silicon

Abstract

It was recently proposed that hydrogen compensation of shallow-acceptor impurities in single-crystal silicon is due to the diffusion of both monatomic oxygen and hydrogen into silicon which combine at acceptor sites to form neutral acceptor-OH complexes. It is shown here that oxygen does not diffuse into silicon under the conditions of shallow-acceptor passivation. Boron-doped silicon was exposed to monatomic deuterium and mass 18 oxygen at elevated temperatures. Depth profiles of D and 18O were measured by secondary-ion mass spectrometry for comparison with the boron concentration. While D readily diffuses into silicon with the concentration nearly equal to that of the boron, no 18O was detectable above the background level. Deuterium profiles in both phosphorus-doped and boron-doped silicon further reveal high densities of deuterium, in excess of the boron concentration, which are ascribed to diffusing monatomic deuterium and deuterium that is immobilized through recombination and impurity trapping.

1Htunneling transport in crystalline Si of different doping

“…The discrepancies with other measurements between 500-900 K, [2][3][4] where much lower diffusion coefficients were found, can be attributed to trapping effects. 25 In particular, this applies to all previous experiments using ion implantation: Lanford et al 26 and Whitlow et al 27 implanted 10 16 1 H/cm 2 at 7.5 and 25 keV, respectively, and Fink et al 28 10 15 -10 17 1 H/cm 2 at 100 keV.…”

Effect of spin polarization for hydrogen adsorbed on Si(111)(1×1) surface: First‐principles calculations

“…The H atom loses electrons to the surface rather than gain electrons as in the LDA results, though the main character of the energy curves are still retained. That the H atom prefers to lose electrons in the silicon bulk was already reported by the experimental studies for the behavior of the H atom in the p-type silicon (e.g., Johnson and Moyer [8]). …”

“…5(d)]. That H atom tends to lose electrons in the silicon bulk was already reported by the experimental studies for the behavior of the H atom in the p-type silicon [8].…”

Hydrogen in crystalline semiconductors

“…Hydrogen was implicated by both groups as the cause for the removal of free holes in the p-type silicon. Secondary ion mass spectrometry (SIMS) of deuterium RF plasma exposed p-type silicon wafers showed that the acceptor and the deuterium concentrations were identical in the deactivated region (13). The deactivation of acceptors by another impurity immediately reminds us of the well known lithium compensation and passivation of acceptors in Si and Ge (14).…”