PRECIPITATION OF OXYGEN IN DISLOCATION-FREE SILICON

The precipitation of oxygen in bulk dislocation‐free Czochralski silicon subjected to isothermal annealing at temperatures between 400 and 1100 °C is studied by means of infrared spectroscopy and transmission electron microscopy. From the changes in the infrared spectra observed after heat treatment it is concluded that (i) for low annealing temperatures (400 to 750°C) the precipitates consist of amorphous SiOx (x < 2) which with rising temperature is transformed into amorphous SiO2, (ii) at medium annealing temperatures (750 to 950 °C) α‐cristobalite precipitates are formed, which (iii) at high annealing temperatures (950 to 1100 °C) are converted in amorphous SiO2. In transmission electron microscopy the temperature range (i) is characterized by the appearance of “rod‐like” defects and its transformation into dislocation loops, and the ranges (ii) and (iii) by the observation of platelet‐shaped precipitates generating dislocation loops and stacking faults, leading to the conversion of the platelet‐shaped precipitates into microprecipitates. Copyright © 1979 WILEY‐VCH Verlag GmbH & Co. KGaA