Effect of oxygen on dislocation movement in silicon

Abstract

The effect of oxygen on dislocation movement in silicon was studied by the method of indentation dislocation rosettes. The size of the rosettes was correlated with the concentration and the state of oxygen in the samples, as determined by means of infrared spectroscopy. In the range of oxygen concentration investigated, up to 1.5×1018 oxygen atoms per cm3, neither interstitially dissolved oxygen nor SiO2 precipitates were found to have any appreciable dislocation-pinning effect. The formation of small oxygen clusters was found to lead to considerable hardening, but at the same time to induce a profusion of dislocation clusters. The oxygen clusters formed in the temperature range from 700 to 900 °C at oxygen concentration levels of ?1×1018 atoms/cm3. The appearance of such clusters was taken to be the reason for the observed broadening of the 1107-cm−1 infrared absorption band and the simultaneous shrinking of its peak height, maintaining an approximately constant integrated peak area.