Changes in the chemical stability of ion-implanted silica glass

Ion or electron irradiation of silica glass produces radiation damage which results in a compaction of the structure, an increase in refractive index and an enhancement of the chemical etch rate in HF. In the light of the present data and comparisons with other measurements it is concluded that the damage produced by electronic energy loss processes differs from that induced by atomic collision events suggesting that they operate by different mechanisms. The electronic energy loss controls the chemical etch rate whereas both the compaction and refractive index changes are influenced more efficiently by the atomic collision events.