MWIR MCT detector process optimization studies at ASELSAN

As the largest defense company in Turkey, ASELSAN A.S. pioneers the development of high performance electro-optical systems. Starting from 2014, significant progress has been made for the mid-wave infrared (MWIR) HgCdTe detector technology including development of Cadmium Zinc Telluride (CZT) substrate, Mercury Cadmium Telluride (MCT) growth and focal plane array (FPA) fabrication as well as Readout Integrated Circuit (ROIC) design. In this paper, recent process optimization studies on MWIR MCT detector technology are presented. p-on-n MWIR MCT layers with Cadmium (Cd) composition of ~0.3 are used for the FPA fabrication. 640x512/15 µm FPAs, which demonstrate the state-of-the-art performances, have been fabricated. Typically, over 99.0% operability and less than 25 mK Noise Equivalent Temperature Difference (NETD) values are attained with a cut-off wavelength of 5 µm at 77K. Among these remarkable results, major improvements have been recorded in pixel uniformity, reliability and reproducibility by revisiting process steps. As a result, process yield has been considerably increased.