In situ mesa etching and immediate regrowth in a HVPE reactor for buried heterostructure device fabrication

Mesa etching in a hydride vapour-phase epitaxy (HVPE) reactor has been studied. Etched depth, underetching and shape of the mesas have been analysed as a function of partial pressures of active gases (HCl, PH₃ and InCl), stripe orientation and etching temperature. The experimental results show that the depth and undercut can be etched independently. We propose qualitative mechanisms for etching each of the emerging crystallographic planes ((0 0 1), (1 1 0) and {1 1 1}). In situ mesa etching with immediate regrowth was applied to the fabrication of buried heterostructure Fabry–Perot lasers. No surface contamination due to exposure to ambient and low process time are advantages of this technique.