J. Phys. IV France 03 (1993) C3-241-C3-246
A comparative study of O2/SiH4 and N2O/SiH4 mixtures for SiO2 deposition in a microwave afterglowH. DEL PUPPO1, J. DESMAISON1 and L. PECCOUD2
1 Laboratoire des Matériaux Céramiques et Traitements de Surfaces, CNRS URA 320, 123 avenue Albert Thomas, 87060 Limoges cedex, France
2 CENG/DLETI, 85X, 38041 Grenoble cedex, France
Silicon dioxide films have been deposited in a microwave afterglow from N2O/SiH4 and O2/SiH4 mixtures. The effect of the pressure and of the substrate to silane injector distance is investigated, and leads to conclude that the growth mechanism is diffusion limited. In complement to previous studies, the composition of films, obtained at several temperatures and oxidant flow rates, is detennined. The gas nature has a low influence on stoichiometry (O/Si˜2 whatever the conditions are) but has an effect on the impurity content. Indeed, when N2O is used, nitrogen is incorporated but, at high temperature, the hydrogen content of the films is lower than for those made from O2. The impurities are thought to come from uneasily desorbed byproducts.
© EDP Sciences 1993