Impact of Technological Parameters on the Low Frequency Noise of Advanced Heterojunction Bipolar Transistors

Usually, the 1/f noise sources in heterojunction bipolar transistors (HBTs) are located in the intrinsic emitter‐base (E‐B) volume, either in the E‐B junction space charge region or at the polycrystalline‐silicon/monocrystalline‐silicon interface in the neutral emitter layer. In this paper, to probe more accurately the location of the noise sources responsible for the 1/f noise, investigations on different HBTs fabricated with different technological parameters are undertaken. First, we have shown that carbon content has a negligible influence on 1/f noise level, but for high carbon content significant generation‐recombination (G‐R) noise components appear. Second, by studying influence of the emitter‐base junction depth, we have shown that the 1/f noise sources are located at the polycrystalline‐silicon/monocrystalline‐silicon interface. Using statistical estimators, we have studied and modelled the dispersion of the 1/f noise. It was found that the dispersion in the noise level increases as the inverse ...