Accuracy of the Fatigue Lifetime of Polysilicon Predicted from its Strength Distribution

This paper discusses the accuracy of the distribution of the fatigue lifetime of polysilicon thin films predicted from their strength distribution. On the basis of the authors’ previous studies, where the fatigue process determining the lifetime was formulated using the well-known fatigue crack extension Paris’ law, prediction error ranges for polysilicon specimens with different levels of strength are determined. The errors of the predicted fatigue lifetime in the logarithmic scale, defined as △log N = |log 10 N exp -log 10 N pred | where N exp and N pred were the experimental and predicted number of cycle, were found to be less than 1 in the range of the cumulative fracture probability F between 0.1 and 0.9. Therefore, based on the measured Paris’ law parameters of polysilicon, the fatigue lifetimes of different polysilicon thin film structures can be predicted from their strength distributions with errors of roughly 10% in the logarithmic scale, which was average of percentages of △log N to log 10 N of experimental data.