noise measurements on HgCdTe field-effect transistors

We performed 1ƒ noise measurements on n-channel Hg1−xCdxTe Metal-Insulator-Semiconductor Field-Effect Transistors (MISFETs) biased in linear and saturation regions of operation at 77 K. The cadmium mole fraction x was approximately 0.29 which corresponds to an energy band-gap of 0.24 eV at 77 K. Through the investigation of the dependence of drain voltage noise power spectral density on gate and drain bias, we estimated the insulator-semiconductor interface trap density as a function of energy. In this analysis, both the noise magnitude and the spectral shape was studied. The frequency span was from 150 Hz to 5 kHz. The noise behavior of the device was modeled using the modified McWhorter Model, originally developed for silicon FETs. The interface trap concentration values computed from the low-frequency noise measurements using the above model were found to agree closely with HgCdTeZnS interface properties measured by capacitance and conductance methods.