Reactive co-evaporation of Si and Ge in oxygen atmospheres

A study of the reactive co-evaporation of Si and Ge in O-2 atmospheres to o btain amorphous Ge:Si:O thin films is presented. The film composition has b een measured using RES, EDX and NRA. The dependence of the Si to Ge concent ration ratio with deposition parameters (single deposition rates, oxygen pr essure and substrate temperature) is analysed. The deviation between the Si to Ge ratio in the films and the ratio of the values set in thickness cont rollers does not depend on the substrate temperature but is influenced by t he presence of an oxygen pressure. A simple model to explain the process be haviour is presented. (C) 1999 Elsevier Science S.A. All rights reserved.