MECHANICAL-STRESS IN AMORPHOUS GE-AS-S(SE) FILM SI SUBSTRATE SYSTEM

Amorphous Ge-As-X (X = S or Se) films have been evaporated on Si subst rates. The mechanical stress created in the system of film and substra te has been studied by Newton rings method. The mechanical stress in f resh films is compressive and slightly depends on the film composition . After bandgap illumination and/or annealing, a stress transition eff ect is observed due to the irreversible photo-and thermo-structural ch anges occurring in the film. The Ge-As-S amorphous films are more sens itive to photo-and thermo-induced changes than the Ge-As-Se films and the stress is smaller in the latter. The explanation of the obtained r esults is based on the changes in the short-and medium-range order in the amorphous film structure. (C) 1997 Elsevier Science S.A.