The Storage Lifetime Model Based On Multi-Performance Degradation Parameters

According to the multi-performance degradation of the bipolar transistor in the accelerating storage process, an extrapolation model of the storage lifetime is proposed. In this model, using the Wiener process simulates the mono-degradation process of each feature degradation; using the copula function describes the correlation among these feature degradations. The Wiener process and parameters in the copula function are considered to associate with the temperature, and their relationships can be represented by the converted equations. Through the maximum likelihood estimation, the parameters in the Wiener process can be found; introducing Kendall's tau, those in the copula function can be estimated. By conducting the regression analyses of the estimated values of the parameters in each stress, their corresponding converted equations can be shown. Based on the storage test data of bipolar transistors, with the estimation method, the storage lifetime is found. The findings show that the model is reasonable for the prediction of storage lifetime.