Some kinetic and thermodynamic aspects of molecular beam epitaxy

Devine, Robert Laurie Smith (1985) Some kinetic and thermodynamic aspects of molecular beam epitaxy. PhD thesis, University of Glasgow.

Abstract

The main aim of the work presented in this thesis is to investigate the role of kinetics and thermodynamics in some of the processes encountered during Molecular Beam Epitaxial growth of III-V semiconductors. Comparisons are made with conventional Liquid Phase and Vapour Phase Epitaxial growth which are governed mainly by thermodynamic and kinetic influences respectively. A symmetry-induced kinetic barrier to the incorporation of group II dopants has been identified by application of gas-phase Molecular Orbital (MO) methods to reactions on solid surfaces. As a precursor to this, MO methods have also been used to explain the nature of the surface dimer structure on the (100) surfaces of semiconductors. A thermodynamic model has been developed to describe the native defect concentrations in GaAs and AlGaAs in an ambient As-overpressure. The applicability of this model to MBE growth is discussed. Conditions leading to the diffusion of Be in GaAs and AlGaAs during growth have been examined. This has led to an understanding of the practical growth limits within which Be-doping can be utilised. Thermodynamic and kinetic factors influencing the behaviour of the Be have been discussed. The above-mentioned effect has been used to provide a controllable source of Be for diffusion studies in AlAs/GaAs superlattices. In particular, the role of the superlattice electronic structure in determining the diffusivity has been illuminated.

• Item Type: Thesis (PhD)
• Qualification Level: Doctoral
• Keywords: Electrical engineering, Thermodynamics
• Date of Award: 1985
• Depositing User: Enlighten Team
• Unique ID: glathesis:1985-76539
• Copyright: Copyright of this thesis is held by the author.
• Date Deposited: 19 Nov 2019 14:11
• Last Modified: 19 Nov 2019 14:11
• URI: https://theses.gla.ac.uk/id/eprint/76539