RESIDUAL-STRESS IN SILICON FILMS DEPOSITED BY LPCVD FROM DISILANE

Measurements of the thermomechanical stress in amorphous silicon films deposited by low pressure chemical vapour deposition (LPCVD) from dis ilane Si2H6 are reported as a function of the deposition parameters (t emperature, gas pressure and wafer spacing). Major influences of the d eposition temperature and the deposition rate are put into evidence an d related to the films ordering and hydrogenation. The effects of a 60 0 degrees C anneal are also investigated and a transition from highly compressive to highly tensile stress is characterised whatever the dep osition. Such behaviour has been explained thanks to hydrogen atoms ou t-diffusion and crystallisation effects. (C) 1997 Elsevier Science S.A .