OPTIMIZATION OF SELECTIVE-AREA EPITAXY FOR FABRICATION OF CIRCULAR GRATING DISTRIBUTED-BRAGG-REFLECTOR SURFACE-EMITTING LASERS

The factors affecting the quality of regrowth of semi-insulating lambd a = 1.1 mum InGaAsP around circular mesas for the fabrication of circu lar grating distributed-Bragg-reflector surface-emitting lasers were i nvestigated. Reactive ion etching of the mesas avoids the exposure of no growth planes on the mesa sidewalls, which results in good regrowth morphology around the entire mesa at a growth pressure of 50 mbar. Hi gh resolution scanning photoluminescence of the regrown quaternary mat erial reveals a minimal 4 nm wavelength shift to longer wavelengths as the mesa edge is approached. A map of the photoluminescence intensity indicates that the quality of the regrown material is uniform around the periphery of the mesas. Fe doping of lambda = 1.1 mum InGaAsP incr eases linearly with reactor gas pressure for fixed dopant and total ga s flows, so the dopant flow must be adjusted for regrowth at a differe nt reactor pressure if the same doping is desired. Activation of Fe in lambda = 1.1 mum InGaAsP is independent of hydride concentration in t he reactor in the range of (2-9) x 10(-5) mol/l, and is virtually comp lete.