Temperature-Dependent Characteristics of HgCdTe Mid-Wave Infrared E-Avalanche Photodiode

Abstract

This paper presents the characteristics of HgCdTe mid-wavelength infrared (MWIR) electron-initiated avalanche photodiodes (e-APDs) as a function of temperature under different biases. The devices show a low dark current density of the order of <inline-formula><tex-math notation="LaTeX">${10^{ - 7}} \text{A/cm}^2$</tex-math></inline-formula> at 80 K when the reverse bias voltage is below 4 V, with an exponential gain above 100 at &#x2212; 8 V. Low excess noise factor of around 1.2 is also demonstrated for the devices at 80 K. The dark current and gain characteristics at different temperatures are analyzed, along with the device simulation results. A varied-temperature impact ionization model for MWIR e-APD devices is adopted based on the experimental results. In addition, a significant increase of the dark current in the APD device is observed at high temperature under large reverse bias, which can be associated with the local electric field redistribution due to the accumulation of holes in the depletion region at high temperatures. The analysis presented in this work paves the way to achieve a high operating temperature (HOT) of the HgCdTe APD with further optimization.