Processing window broadened by a barrier structure in dual-band HgCdTe IRFPAs

Dual-band HgCdTe IRFPAs are one of the most important developing frontiers for 3rd generation IRFPAs. A barrier has been implemented in the dual-band HgCdTe detectors to overcome the electrical cross-talk between two layers with different compositions. Moreover, we now reveal another benefit of this barrier structure. This barrier can relieve the critical demands in photo-lithography of the implantation process, which shows great advantages as the dimension of a single element in an advanced dual-band IRFPAs is becoming less than 30μm. When the implantation pattern migrates about 2μm, the profile in the dual-band structure is exposed under implantation. An n-type connection between LW layer and MW layer will be created. Without a barrier, the dark current of the MW layer is completely ruined by fractions from the LW layer. While a modified barrier is utilized, the dark current can be restrained to the same order as those with perfect implantation.