Improving material characteristics and reproducibility of MBE HgCdTe

Abstract

This paper describes our progress to improve the material quality, reproducibility, and flexibility of molecular beam epitaxial (MBE) growth of HgCdTe. Data, statistics, and yields according to defined screen criteria are presented for n-type layer carrier concentration and mobility, void defect density, and dislocation density for more than 100 layers. Minority carrier lifetime data are also presented. Continued improvements in impurity reductiont have allowed us to achieve, for the first time, reproducible, low n-type carrier concentration in the mid-10¹⁴ cnr⁻³ range with high electron mobility. Data are presented that show that low dislocation density films are obtained for growth on CdZnTe substrates with a wide range of Zn concentration. Results are presented from a nine-growth run first pass success demonstration run to further assess material quality reproducibility and flexibility of wavelength band tuning. These results demonstrate the promising potential of MBE growth for flexible manufacturing of HgCdTe for infrared focal plane arrays.