High frequency noise calculation in Schottky metal-semiconductor-metal structure and parameter retrieval of nanometric CdTe structure

An analytical model to calculate the noise spectral density in Metal-Semiconductor-Metal (M-S-M) structure of Schottky contacts has been developed. The model based on the linearization of Langevin approach of carrier motion inside a bulk semiconductor, and taking into account the fluctuations in the leakage current through the structure due to the barrier lowering by the image force effect. Particularly, the calculations describe two quantities of noise: electric field and total current spectral densities. The results obtained from the Au-CdTe-Au Schottky structure exhibit sharp resonances due to the effect of plasma frequency oscillations and the relative thickness of the depletion region below the anode. Moreover, the noise current spectrum exhibits Lorentzian behavior when the M-S-M has the form of a homogenous structure (thickness of depletion region ≈ 0). These results are in agreement with that reported by Monte Carlo technique of metal Schottky structure. The discussion of the noise spectra as a function of structure parameters revealed that the nanometric M-S-M structures with undoped CdTe can be used as Schottky detectors/emitters in Terahertz frequency applications.