In situ sensor for interstitial trapping during Si thermal oxidation usingHe 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 ox ide thickness and follows the same time dependence. The captured interstiti al surface density ranges between 10(15) and 10(16) cm(-2). The amount of c aptured interstitials for a given oxide thickness is temperature independen t above 1050 degreesC, but below that it decreases, indicating the presence of competing defect centers for the capture of interstitials. The method d emonstrates the possibility to use void layers as in situ sensors for inter stitials. (C) 2001 American Institute of Physics.