Symmetric InP mirror facets fabricated by selective chemical beam epitaxy on reactive-ion-etched sidewalls

Abstract

Vertical (0 1 1)-oriented parallel mirror facets as smooth as cleaved ones were obtained by selective chemical beam epitaxy (CBE) on both sidewalls of [011]-direction ridges formed by reactive ion etching (RIE) on a (100) InP substrate. The obtained vertical facets often had a symmetric shape on the both sidewalls of the ridge, which was required to use as Fabry-Perot mirrors in a semiconductor laser, although an asymmetric shape had been often obtained before optimizing the growth conditions. We clarified the cause of asymmetry using simulation of the flux distribution on the sidewalls of the ridge during growth, and found the optimum growth conditions to obtain symmetric and parallel mirror facets.