Oxidation of a-Si:H Stress behaviour in the grown oxide

Abstract

The stress behaviour in thin thermally oxidized a-Si:H films at temperatures ranging from 850 to 1060°C has been studied by means of ellipsometry and by measuring the radius of sample curvature at room temperature. It has been established that the oxidation of amorphous Si at Iow and intermediate temperatures induces smaller compressive stresses in the oxide than those obtained by oxidation of crystalline Si. At oxidation temperatures higher than 950°C the stress is tensile with a trend to increase with increasing oxidation temperature. Precrys-tallization of the amorphous films led to higher stress in the growing oxide, which is compressive for all the oxidation temperatures used.