Electrical deactivation of arsenic as a source of point defects

The effect of electrical deactivation of arsenic in silicon has been studied. High concentrations of arsenic were implanted and laser melt annealed, creating boxlike fully electrically active arsenic layers, with no residual implant damage. Wafers were then subjected to low temperature thermal cycles while a buried boron layer monitored point defects. Strong enhancements in the boron diffusion were observed suggesting that arsenic deactivation releases large numbers of interstitials. This is explained by a process where the vacancies required by the deactivated arsenic structures are created through a deactivation assisted Frenkel pair generation process, thus injecting interstitials.