Infrared Avalanche Photodiode Detectors

This study presents on the design, fabrication and characteristics of HgCdTe mid-wave infrared avalanche photodiode (MWIR APD). The gain of 800 at - 8 V bias is measured in n+-ν-p+ detector array with pitch size of 30 μm. The gain independent bandwidth of 6 MHz is achieved in the fabricated device. This paper also covers the status of HgCdTe and III-V material based IR-APD technology. These APDs having high internal gain and bandwidth are suitable for the detection of attenuated optical signals such as in the battle field conditions/long range imaging in defence and space applications. It provides a combined solution for both detection and amplification if the detector receives a very weak optical signal. HgCdTe based APDs provide high avalanche gain with low excess noise, high quantum efficiency, low dark current and fast response time.