GROWTH OF BURIED OXIDE LAYERS OF SILICON-ON-INSULATOR STRUCTURES BY THERMAL-OXIDATION OF THE TOP SILICON LAYER

We have investigated the thickness increase of buried oxide layers in silicon-on-insulator structures by thermal oxidation of the top silico n layer. A thermodynamic model is derived based on the experimental ob servation that oxidation introduces an oxygen concentration into silic on which is above its solubility limit. Experiments on buried oxide gr owth by thermal oxidation of the top silicon layer were performed with specially designed bond-and-etchback silicon-on-insulator structures in the temperature range between 1100 and 1200 degrees C. The results obtained are compared to the thermodynamic model and to data from othe r growth experiments. The different buried oxide growth rates observed for different types of silicon-on-insulator material are discussed in terms of different silicon self-interstitial supersaturations which a re induced in the top silicon layer during oxidation.