| This thesis emphasizes on the process of making high quality InAs and related alloys on GaP substrates despite the existence of an 11% lattice mismatch. In particular, this work presents the invention and development of a novel Liquid Phase-Molecular Beam Epitaxy (LP-MBE) growth technique.; The LP-MBE works by growing a thin (25--50A) In-stabilized InAs initial layer on GaP at around 500°C, followed by the growth of As-stabilized InAs at the same substrate temperature. The arsenic flux is selected such that the InAs growth occurs near the In-to-As stabilized reconstruction transition region; i.e. just slightly In-rich and slightly arsenic-rich during the growth of In-stabilized InAs initial layer and normal As-stabilized InAs respectively.; This growth technique shows a reduced InAs surface defect density by one order of magnitude to ∼103 cm-2. The InAs surface is free of cross-hatch as observed by Nomarski phase-contrast microscopy. The surface roughness of InAs has been improved to 13.67A as measured by AFM. HRTEM of InAs/GaP interface shows possible formation of InxGa1-xAsyP1-y graded layer which leads to these improvements. Phase diagram modelings and several ways to test the existence of this graded layer are discussed.; It is also shown that incorporating the Strained-Layer Superlattice (SLS) that acts as dislocation bender into LP-MBE grown InAs/GaP improves InAs electrical properties. The background carrier concentration of InAs is reduced to about 3 x 1016 cm-3 and an electron mobility of over 12,000 cm2/V-s has been achieved, as measured by Hall effect. ECV measurements also confirm these improvements.; In addition, it is also demonstrated that LP-MBE method can be used to grow other lattice-mismatched materials such as InP on GaP with a 7% lattice mismatch.; This work is patent pending. |
