Reduced damage reactive ion etching process for fabrication of InGaAsP/InGaAs multiple quantum well ridge waveguide lasers

The damage introduced into an InGaAs/InGaAsP quantum well structure during CH₄/H₂ reactive ion etching (RIE) processes was measured, for plasma powers from 20 to 100 W, using low temperature photoluminescence. The damage depth profile is estimated to be around 12-70 nm after annealing at 500°C for 60 s using a rapid thermal annealer. A reduced damage RIE process has been developed to fabricate InGaAs/InGaAsP multiquantum well ridge waveguide lasers. The performance of these lasers has been compared to that of lasers fabricated from the same epilayer using wet etching to form the ridge. The resultant threshold currents were essentially indistinguishable, being 44.5 and 43 mA, respectively, for dry and wet etched lasers with 500 μm long laser cavities.