Structural properties and defect formation mechanisms in MBE-grown HgCdTe on InSb (211)B substrates

This work investigates the structural properties of HgCdTe thin films grown on InSb (211)B substrates using molecular beam epitaxy (MBE). The Cd composition of thin films is accurately determined using non-destructive approaches based on x-ray diffraction (XRD) and reflectance infrared spectroscopy. The as-grown HgCdTe thin films exhibit characteristic surface defects with a size of 7-10 mu m and density of similar to 10(5) cm(-2), resulting in an additional spread in XRD full width at half maximum. Cross-sectional transmission electron microscopy results indicate that these defects are caused by surface In droplet formation during the oxide removal process of InSb substrate, which subsequently results in the formation of In4Te3 inclusions and extended defects in MBE-grown HgCdTe. Our findings provide additional confirmation that suppressing thermally induced damage of the InSb substrate is necessary for fabricating high-performance infrared detectors using HgCdTe grown on InSb substrates. (c) 2023 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).

Automated summary

This study investigates the structural properties of HgCdTe thin films grown on InSb (211)B substrates using molecular beam epitaxy (MBE). The Cd composition of the films is accurately determined using non-destructive approaches. The study found that surface defects in the as-grown HgCdTe thin films are caused by the formation of In droplets during the oxide removal process. These findings further confirm the importance of suppressing thermally induced damage.