Very rapid and selective epitaxy of InP around mesas of height up to 14 μm by hydride vapour phase epitaxy

Selective growth of InP and related materials on patterned planar and non-planar substrates is one of the key steps in the fabrication of discrete and integrated optoelectronic devices. Growth of current blocking InP layers around the edge emitting laser (EEL) mesas are successfully used in many laboratories. In recent years, not only quantum wells have replaced the bulk active layers in the laser structures, but also, more and more advanced optoelectronic component structures continue to emerge; besides, ever since the successful demonstration of electrically pumped long wavelength vertical cavity surface emitting lasers (VCSEL) at low temperatures, there is an increasing urge to demonstrate it at room temperature. Both these situations set special demands on the selective regrowth of semi-insulating InP:Fe around mesas for current confinement, namely, a) the regrowth has to be rapid enough to avoid excessive quantum well mixing and unwanted dopant diffusion and b) it has to be successful even if the mesas are ~10 μm high as in the case of VCSEL mesas. The purpose of this paper is to address these two points. Hydride Vapour Phase Epitaxy (HVPE) is best suited for the purpose owing to its selectivity, planarity and high growth rate. After successful regrowth of current blocking InP by HVPE for fabricating three types of edge emitting lasers (EEL) such as Fabry-Perot(FP), Distributed Feed Back (DFB) and Distributed Bragg Reflector (DBR) lasers, we have extended our studies to the regrowth of InP around cylindrical and cuboidal mesas of height up to 14 μm with the intention of fabricating electrically pumped VCSEL. To the knowledge of the authors, such studies have not been reported. Here we present a comparison of the regrowth aspects in EEL and VCSEL cases. We also present a summary of certain device results of EEL fabricated by incorporating this technique