In situ sensor for interstitial trapping during Si thermal oxidation using He implantation-induced voids

The shrinkage of voids created by He implants in silicon has been measured during thermal oxidation. The empty volume is filled by self-interstitials injected during oxidation. The increase in volume is proportional to the oxide thickness and follows the same time dependence. The captured interstitial surface density ranges between 10(15) and 10(16) cm(-2). The amount of captured interstitials for a given oxide thickness is temperature independent above 1050 degreesC, but below that it decreases, indicating the presence of competing defect centers for the capture of interstitials. The method demonstrates the possibility to use void layers as in situ sensors for interstitials.