Hydrogen and helium implantation in vitreous silica

The effects of 150–300‐keV He⁺ and H⁺ implantation in vitreous silica have been examined by optical absorption spectroscopy, optical and scanning electron microscopy, gas reemission measurements, and microtopography. No surface blistering or exfoliation was observed at any implant temperature (≲200° to ∠800 °C), at fluences in excess of 10¹⁹ ions cm⁻². The amount of compaction of the implanted layer was determined for high‐fluence ion implantation and compared with existing data. Optical absorption studies show evidence for beam‐assisted chemisorption, defect formation, and, with hydrogen implantation, the formation of large (∠10²² cm⁻³) concentrations of hydroxyl. Experimental results are correlated with gas diffusivity and solubility. Implications for fusion reactor applications are discussed.