The effect of electrode process on properties of HgCdTe detectors

Abstract

Performance of HgCdTe devices was limited by many factors such as materials and techniques, etc. And the electrical characteristics of electrode contacts on HgCdTe played important roles．Because Ar Ion Beam Etching could make the conductivity type conversion of p-type HgCdTe material, it was used to obtain n-type electrode area on the slight-p type HgCdTe material. Variable magnetic field Hall measurements were performed on n-type and slight p-type HgCdTe material before and after Ar Ion Beam Etching at 77 K. The mobility spectrum analysis (MSA) technique was employed in this paper to obtain the electrical parameter of HgCdTe. Comparing the electrical parameters of HgCdTe before and after etching, we knew that Ar Ion etching formed high doping concentration n-type area on slight p-type HgCdTe. The minority carrier lifetime of HgCdTe was studied using the photoconductive decay technique. By measuring the minority carrier lifetime of the same HgCdTe material with or without n-type electrode, it was found that the minority carrier lifetime of slight p-type HgCdTe with n-type electrode was higher than HgCdTe that was without n-type electrode at low temperature. The results showed that the n-type electrode could improve the minority carrier lifetime of slight p-type HgCdTe. In addition, by changing the distance of the n-type electrode area to the photosensitive area, it was researched that the impact of n-type electrode area on the device performance. With the decrease of distance, the device performance improved. It was proved that n-type electrode areas also could improve the performance by device fabrication.