STUDY OF THERMAL-BEHAVIOR OF OXYGEN IN SILICON-CRYSTALS BY ANALYSIS OF X-RAY PENDELLOSUNG FRINGES

The thermal behaviour of oxygen in Czochralski (CZ) silicon and magnet ic Czochralski (MCZ) silicon crystals was investigated by analysis of Pendellosung fringes based on the statistical theory of X-ray dynamica l diffraction. The size and the density of oxygen precipitates were de termined for different annealing temperatures and/or different times. It was observed that oxide precipitates in the samples increase in siz e and decrease in density with time during isothermal annealing at 102 3 K. The precipitation in MCZ silicon approaches saturation level afte r annealing for 250 h. It was found that the size of precipitates incr eases rapidly with annealing temperature in isochronal annealing for 1 8 h. Comparison of the results of MCZ silicons with those of CZ silico ns shows that MCZ crystals are thermally more stable. This suggests th at magnetic fields can control the oxygen concentration effectively an d that the MCZ and CZ silicon have different thermal behaviours. A pow erful technique for detecting microdefects of nanometre size and rando m distribution is described.