Optoelectronic structure fabrication by organometallic vapor-phase epitaxy and selective epitaxy

Abstract

NOTE: Text or symbols not renderable in plain ASCII are indicated by [...]. Abstract is included in .pdf document. The internal configuration and external supports of OMVPE reactors are examined. The quality of epitaxial layers deposited by an OMVPE reactor is strongly influenced by its internal configuration. The quality of the external supports determines the safety, the environmental impact, and the operating efficiency of the OMVPE reactor. Optoelectronic structures are fabricated by selective epitaxy. The morphology and growth behavior of GaAs, AlGaAs, and InGaAs using selective epitaxy are presented. Highly selective growth can be achieved through the use of organometallic compounds which contain halogens. The selective growth of nanometer-scale GaAs wire and dot structures is demonstrated. Spectrally-resolved cathodoluminescence images as well as pectra from single dots and wires, passivated by an additional AIGaAs layer, are presented. A blue shifting of the GaAs luminescence peak is observed as the size scale of the wires and dots decreases. Formation of highly-uniform and densely-packed arrays of GaAs dots by selective epitaxy is described. The smallest GaAs dots formed are 15-20 nm in base diameter and 8-10 nm in height with slow-growth crystallographic planes limiting growths of individual dots. Completely selective GaAs growth within dielectric-mask openings at these small size-scales is also demonstrated. The technique of facet-modulation selective epitaxy and its application to quantum-well wire doublet fabrication are described. The smallest wire fabricated has a crescent cross-section less than 140 [...] thick and less than 1400 [...] wide. The development of OMVPE epitaxial layers for a visible-wavelength vertical-cavity surface-emitting laser (VCSEL) is presented. The defect density of the mirror layers was reduced to a negligible level by optimizing gas switching. Electroluminescence spectrum of an InGaP heterostructure p-n diode is presented. The defect density of the active region was also reduced to a negligible level by optimizing the gas-switching sequences