Junction Formation Processing of MWIR Small-Pitch HgCdTe Detectors

Small-pitch HgCdTe detector is a strong trend in IR imaging. It requires focal plane arrays with small pixels. The key factors including injection dose and Hg vacancy concentration during HgCdTe junction formation were studied. A special designed junction spacing experiment was used to directly measure the junction expansion. The simulation of junction expansion through numerical method was carried out to interpret the physical mechanism of junction expansion in HgCdTe. Moreover, a pixel array test using the suggested parameters obtained in junction spacing experiment and simulation was also carried out. It validates the correctness and effectiveness of the experiment and the numerical model. This work gives fundamental concept of junction formation in HgCdTe, shows the proper parameters for fabricating the small-pitch detectors, and provides numerical model for simulation and optimization of HgCdTe junction design.