Indexed on: 08 Jun '13Published on: 08 Jun '13Published in: Journal of Electronic Materials
Characterization of mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) HgCdTe focal-plane arrays (FPAs) indicates that limitations on operability at elevated temperatures are due to detector dark current and excess 1/f noise. Dark-current models in HgCdTe are well established and understood; however, the same cannot be said for 1/f noise. In this paper we propose two models for separate sources of 1/f noise in HgCdTe photodiodes based upon charge fluctuations out of McWhorter-like surface traps. The two 1/f noise components are designated as (1) systemic, being associated with passivated external surfaces of the diodes, and (2) isolated defect, being, it is proposed, associated with the internal surfaces of built-in physical defects such as dislocations. The models are utilized to explain data measured on LWIR and MWIR test-diode structures, and predictions are made regarding the performance of MWIR and LWIR FPAs at elevated temperatures.