1/f Noise model for PNP bipolar junction transistors based on radiation effect

It is found that ionizing-radiation can lead to 1/f noise degradations in PNP bipolar junction transistors. In this paper, it is suggested that the surface of the space charge region is the main source of the base surface 1/f noise. A model is developed which identifies the parameters and describes their interactive contribution to the base surface recombination current at the surface of the space charge region. Based on the theory of carrier number fluctuation and the model of base recombination surface current, a 1/f noise model is developed. This model suggests that the 1/f noise degradations are the result of accumulation of oxide-trapped charges and interface states. The radiations were performed in a Co⁶⁰ source at a dose rate of 0.1Gy(Si)/s up to a total dose of 700Gy(Si). The model can explain well the experimental results.