In-situ ellipsometry monitoring of MBE grown cadmium zinc telluride(211)boron/silicon(211) and cadmium telluride(211)boron/silicon(211) structures

In this thesis the application of spectroscopic ellipsometry (SE) to the monitoring of the epitaxial growth of CdZnTe(211)B/Si(211) was developed.; Studies of the II–VI optical dielectric function were performed based on CdTe temperature measurements, in which E₁ critical point (CP) energy temperature dependence was found to be sufficient for temperature referencing, while highly dispersive E₀ and E₀+Δ₀ CP regions were identified as suitable references for the CdZnTe compositional analysis. Multiple spectral differentiation of the dielectric function allowed extraction of the weak E₀+Δ ₀ CP energy from the temperature SE data using the parametric model. This model was tuned to provide the best fits of the temperature data with only a minimal number of adjustable model parameters. The model was shown to demonstrate acceptable precision in the determination of composition (∼0.5%) and temperature (<5°C) to be successful in real-time SE analysis.; The development of an alternative method of Zn composition measurement at the beginning of CdZnTe layer growth based on the dynamic SE data analysis at several wavelengths has also been reported and evaluated for the analysis precision.; A considerable improvement in the SE experiment has been demonstrated in this work. The real-time correction algorithm was developed to compensate the raw spectral data for the distortions caused by the sample beam wobble and thermal displacement of the wafer inside the MBE reactor.; In the experimental part, this thesis is focused on the understanding of real-time ellipsometry results on the CdTe/Si(211) structures. Some of its aspects included the interpretation of the dynamic data from CdZnTe/CdTe, evaluation of the surface roughness as a surface morphology monitoring reference, studies of the dynamic heating and cooling processes in existing current free wafer mounting configuration and other related issues.; The experimental part of the thesis is followed by the closing discussion on the future prospects for the proposed SE monitoring in the development of better-controlled epitaxy on CdTe/Si and CdZnTe/Si alternative substrates for the subsequent MCT heterostructures growth.