High-performance VLWIR MBE HgCdTe photoconductive detectors

Bulk grown wafers had been used for fabricating photoconductive (PC) HgCdTe detectors for several decades until recent years. As bulk wafers are getting gradually depleted over years, epitaxial grown HgCdTe wafers are becoming the only choices available. This paper reports the very long wavelength Infrared (VLWIR) PC HgCdTe detector development (cutoff wavelength ~ 17μm at LN2) at Teledyne, leveraging the state-of-the-art molecular beam epitaxy (MBE) material technology on CdZnTe substrates. These MBE wafers provide much larger wafer sizes, better uniformity, and in general better detector performance than conventional bulk wafers. Detailed detector performance comparison was performed between MBE and bulk wafers on detectivity (D*), responsivity, spectral response, etc. for 1mm and 0.25mm discrete detectors. The VLWIR MBE PC HgCdTe detectors are now in volume production at Teledyne.