Removal of deuterium from co-deposited carbon–silicon layers

The composition of co-deposited carbon–silicon layers (a-C:Si:D) with varying Si concentrations and their removal by heating in air were investigated using MeV ion beam techniques. The ion-induced release of D due to the analysing beam (1.2 MeV 3He) was determined. The removal rates of D and C by heating in air increase strongly at temperatures around 550 K for a-C:D layers. With increasing Si content, these temperatures rise to above 650 K for layers with Si concentrations larger than 0.2 Si/(Si+C). The C removal rate is always lower than the D removal rate. Si is not removed by this method. The observed properties of the layers are compared with those of hard and soft a-C:D films.