Minority-carrier-induced release of hydrogen from donors in silicon

The time dependence of Schottky-barrier depletion layer charge density is monitored after injection of holes in P- and As-doped Si containing donor/hydrogen pairs. The resultant hole capture event leads to the reactivation of hydrogenated donors. In contrast to the observations of Johnson et al., we see an essentially abrupt change in this capacitance, and little, if any, transient behavior that can be attributed to the sweepout of ${\mathrm{H}}^{+}$ or the conversion of ${\mathrm{H}}^{\mathrm{-}}$ to neutral or positively charged hydrogen. Since we observe that much of the hole-induced charge density disappears after a few days wait under dark conditions, it appears that this reaction is at least partially reversible. We conclude that this experiment provides no direct confirmation of the existence of positively or negatively charged hydrogen.