In Situ Spectroscopic Ellipsometry for Real Time Composition Control of Hg 1−x cd x Te Grown by Molecular Beam Epitaxy

Spectral ellipsometry (SE) was applied to in situ composition control of Hg 1−x Cd x Te grown by molecular beam epitaxy (MBE), and the impact of surface topography of the Hg 1−x Cd x Te layers on the accuracy of SE was investigated. Of particular importance is the presence of surface defects, such as voids in MBE- Hg 1−x Cd x Te layers. While dislocations do not have any significant impact on the dielectric functions, the experimental data in this work show that MBE- Hg 1−x Cd x Te samples having the same composition, but different void densities, have different effective dielectric functions.