Thermal donors and carbonoxygen defects in silicon

Abstract

Results of annealing experiments with Czochralski (CZ) silicon are reported. Formation and reduction of thermal donors (TDs) is studied as well as of carbonoxygen‐related defects. The experimental methods used are IR‐absorption spectroscopy and resistivity measurements. The experimental results support a formation process of TDs at 450 °C on nuclei preexisting in silicon. Some of these nuclei are stable at high temperatures (or reform during cool‐down) and it is suggested that oxygen atoms aggregate at theese clusters during 450 °C treatment. Three different nuclei are suggested. Carbonoxygen complexes formed at 450 °C are found to contain two oxygen atoms for each carbon atom. They appear to be electrically neutral. From repeated heat‐treatments at 450 °C it is also found that other oxygen‐related defects than TDs and CO‐complexes are developing, such as oxygen precipitates. Copyright © 1987 WILEY‐VCH Verlag GmbH & Co. KGaA