The diffusion of hydrogen in silicon and mechanisms for “unintentional” hydrogenation during ion beam processing

Experiments are described in which hydrogen is injected into silicon by various techniques and detected by the neutralization of boron acceptor sites. Wet chemical etching is shown to inject protons several microns in a few seconds; this experiment is used to set a lower limit on the diffusivity of hydrogen of ⋍2⊠10⁻¹¹ cm²/s at 300 K, a number in reasonable agreement with prior estimates deduced by Van Wieririgen and Warmholtz from high-temperature permeation measurements. A number of experiments are reported to elucidate the mechanism for “unintentional” hydrogenation occurring during argon ion bombardment. The data suggest that this effect is caused by bombardment-induced injection of hydrogen from surface H₂O/hydrocarbon contaminants.