Dislocation-free large area InP ELO layers by liquid phase epitaxy

Abstract

Epitaxial lateral overgrowth (ELO) was performed on {0 0 1}-oriented InP substrates by liquid phase epitaxy at constant growth temperature (450–650 °C). In this work, ‘line and space’ (L&S) and L-shaped patterns were formed on the substrates before epitaxy, and then the as-grown and etched surfaces were observed by Nomarski interference optical microscopy. Defect etching revealed dislocation etch pits on both the open seed areas and the coalescence regions of the ELO layer formed on the L&S patterns. However, when using the L-shaped pattern, etch pits were only observed on the open seed regions of the ELO layer. We show that the ELO layers that spread laterally inside the L-shaped pattern are dislocation-free. In addition, large area ELO layers were obtained when the L-shaped pattern was modified by rotating the direction in which it was facing. In the case of the L-shaped pattern, the optical properties of the ELO layer were improved compared with those on the open seed area.