Defect annealing in polycrystalline silicon films

Abstract Studies of the isochronal annealing of paramagnetic vacancy-type defects (VV centres) in polycrystalline silicon films by electron spin resonance are reported. Silicon films of 1 and 10 μm thickness were deposited by the thermal decomposition of silane at 700–800°C in N 2 and H 2 atmospheres. The number N VV (cm -2 ) of VV centres in the films after their deposition was found to be approximately (3–4)x10 14 cm -2 . During annealing in the 450–750°C temperature range a considerable increase in N VV was observed, the increase depending on substrate temperature and structure (amorphous or monocrystalline). From this we conclude that intrinsic stresses in polycrystalline films are responsible for the increase in N VV . On comparing the data for the annealing of polycrystalline films with the results on the annealing of amorphous silicon produced by ion implantation we reach the conclusion that the disappearance of VV centres in the second case is due to an interaction with mobile point defects rather than to the thermal decomposition of the VV centres.