Hydrogen dissolution in and release from nonmetals. II. Crystalline silicon

Abstract

The solubility of hydrogen in crystalline silicon from 1363–1473 K and from 1.7–9.2 atm has been measured using the method of high-temperature, high-pressure infusion followed by high-temperature vacuum outgassing with mass-spectrometric detection. The measured solubilities were in the range 1–5×1016 atoms/cm3 and exhibited a temperature dependence consistent with a heat of solution of 30–40 kcal/mole. The pressure dependence of the solubility was consistently smaller than the square-root dependence characteristic of simple interstitial solution. The release-rate curves showed multiple peaks, which are incompatible with the classical diffusion model of release. Instead the peaks correspond to trapping of hydrogen at distinct binding sites in the silicon lattice. The release kinetics were modeled as detrapping processes.