Low-Frequency Noise Characteristics of HgCdTe Infrared Photodiodes Operating at High Temperatures
We present experimental results of 1/f noise characterization in n+/p mercury-vacancy-doped photodiodes. The 1/f noise was measured as a function of temperature and diode bias voltage for different photodiode configurations. We have investigated the 1/f noise of devices with various geometries and structures, in different spectral bands, and produced using different growth processes. Contrasting 1/f noise behavior was observed in mid-wavelength infrared range (MWIR) and long-wavelength infrared range (LWIR) devices. The results indicate that the 1/f noise in MWIR photodiodes is proportional to the diode area, which implies the presence of a previously unreported noise-generating mechanism occurring in bulk material. The 1/f noise in the LWIR photodiodes was found to be independent of diode geometry, indicating the presence of a diffusion current modulation at specific points of the junction.