Abstract
A spatially selective quantum well intermixing process, using phosphorus-doped silica (SiO2:P) containing 5 wt% P to inhibit intermixing and pure SiO2 to enhance intermixing, is presented. The SiO2:P cap has been found to suppress bandgap shifts in both p-i-n and n-i-p GaAs/AlGaAs quantum well laser structures, with bandgap shift differences as large as 100 meV observed from samples capped with SiO2 and with SiO2:P after rapid thermal processing at temperatures as high as 950 degrees C for 60 s. Extended cavity ridge lasers exhibited low threshold currents with TE losses of 3.2 cm(-1) measured in the passive waveguide sections at the lasing wavelength using the Fabry-Perot resonance method. This value is among the lowest reported so far using an impurity-free disordering technique.