Epitaxial growth of III-V materials on silicon substrates by MOVPE

In this study a range of materials structures was prepared by the deposition of GaAs layers on (100) silicon substrates using a two-step MOVPE approach. A low temperature initiation layer was grown directly on to the substrate at 400°C, a thermal anneal was carried out, and an intermediate buffer layer grown at 750°C, followed by the deposition of the GaAs, GaAs/GaAlAs or GaInAs device layers. An investigation was made into the effect of intermediate buffer layers containing different combinations of GaInAs/GaAs strained layer superlattices (SLS) and GaAs spacer layers on the dislocation content of the material. Materials assessment of these structures were carried out using double crystal X-ray diffraction, optical microscopy, defect revealing chemical etching and plan view and cross-sectional TEM. The electrical properties were characterised by mercury probe CV profiling, van der Pauw measurements and Schottky diode fabrication