Performance of Very Low Dark Current SWIR PIN Arrays

In photon counting imaging applications a focal plane array consisting of a detector and readout integrated circuit (ROIC) array must both be low noise. At room temperature, InGaAs PIN detector arrays are most suitable because the required signal bandwidth is fairly modest and the first stage input amplifiers on the ROIC can be very low noise. However, in many applications relatively long integration times demand that the input dark current from the PIN detector be held to an absolute minimum to retain photon counting sensitivity. In some cases this means that the dark current specification flowed down to the PIN pixel calls for less than 10 fA of dark current. This is a very demanding specification that requires both very high quality material as well as careful attention to device design and processing.