CREATION OF METASTABLE DEFECTS IN A-SI-H BY KEV-ELECTRON IRRADIATION AT DIFFERENT TEMPERATURES

The creation of metastable defects in a-Si:H films by 20keV-electron i rradiation at different degradation temperatures, T-deg, is investigat ed. At low degradation temperature (T-deg = -170 degrees C) no signifi cant difference in the defect creation kinetics compared to that at ro om temperature is observed. This result indicates that the defect crea tion mechanism is not thermally activated. At higher degradation tempe ratures (T-deg = 50-100 degrees C) the defect creation kinetics is str ongly dependent on temperature, T-deg, and electron intensity, I-el, d ue to an increasing influence of thermal annealing during degradation. To explain these effects quantitatively an expression for the defect creation kinetics is derived based on a model assuming different kinds of defects with different annealing behaviour. Moreover, the resultin g fit parameters give further information for the understanding of the multi-valued relation between photoconductivity, sigma(ph), and defec t density, N-D, observed for different degradation states.