Patterned substrate overgrowth for optoelectronic device integration using chemical beam epitaxy (CBE)

Abstract

InGaAs/InP layers are grown on (1 0 0) substrates patterned using chemically assisted ion beam etching (CAIBE) to produce undercut mesas aligned along the 〈0 1 1〉 direction. Undercut mesas are used to avoid any interaction between growth on the etched and non-etched regions of the substrate. We show that optimised growth conditions for InP produce (1 1 1)B facets on the sides of the ridges which are atomically smooth along their full length. These ridges form an excellent template for the diffusion of the group III species onto the (1 0 0) plane in the ridge centre. The success of this technique relies heavily on the quality of the growth template used since the diffusion of group III species off the higher-order (n 1 1) planes onto the (1 0 0) is plane specific. The formation of this template by growth rather than wet chemical etching results in atomically smooth facets of a well-defined orientation and height, which is well suited to our application.