GRINSCH GaInAsP MQW laser structures grown by MOMBE

Abstract

For applications in long wavelength MQW lasers, GaInAsP/InP heterostructures were grown by metalorganic molecular beam epitaxy (MOMBE or CBE). The growth process was performed with all gaseous sources for group III, group V and dopant precursors. In addition to the standard strained MQW laser structure with two quaternary separate confinement layers on each side of the active MQW region, laser structures with continuously graded GaInAsP confinement layers (GRINSCH) were prepared. In the latter case all group III and group V flows were ramped synchronously while maintaining lattice matching growth conditions. By this method a parabolic variation of the band gap was obtained. Data from first test lasers are comparable to those from standard lasers revealing the high material quality of MOMBE grown InP-based GRINSCH structures. Besides standard strained quaternary layers InAsP layers with compressive strain up to 2% were used as quantum wells, and InAsP MQW lasers with emission wavelengths of both 1.3 and 1.55 μm were fabricated. Moreover, an excellent MQW wavelength uniformity (standard deviation Δ λ⩽2 nm) across areas larger than 95% of a 2″ wafer along with proven thermal stability demonstrates the high yield of the process for all structures revealing the feasibility of this material for industrial use.