Investigation of 1/f noise sources with the coherence function

We demonstrate the application of the coherence function to analyze the 1/f noise sources in a planar semiconductor structure with multiple electrical contacts. This article includes noise and coherence function measurements, the 1/f noise model for the transmission-line-model (TLM) sample, theoretical calculations of the coherence function, and a comparison of theoretical and experimental values. In the developed noise model, bulk semiconductor noise and metal–semiconductor contact noise are considered noise sources. It was shown that the experimental results of coherence measurements are well explained by the model, which assumes 1/f noise from contacts and no 1/f noise from a bulk semiconductor. The presented method can be used to find dominant noise sources originating from bulk semiconductor or metal–semiconductor contacts in planar structures. The strength of the method, in comparison with models based only on power spectral density, is straightforward interpretation and the lack of sophisticated model parameters.