High spatial resolution quantum well intermixing process in GaInAs/GaInAsP laser structures

Quantum well intermixing (QWI) has been developed in III-V semiconductors to modify the quantum well (QW) profile in selected regions to enhance the blue shift of the optical absorption edge after growth. Laser induced disordering (LID) is one of the QWI techniques, which is impurity free and offers the possibility of direct writing capability. Pulsed-photoabsorption induced disordering (P-PAID) is a LID technique whereby the absorption of high-energy pulses from Nd:YAG laser pulses causes bond breaking and lattice disruption leading to an increased density of point defects. Subsequent high temperature annealing results in diffusion of the point defects and enhances the QWI rate. The laser pulses used were of similar duration to the thermal time constant of InP in order to minimize the effects of lateral diffusion. So far, photoluminescence (PL) spectroscopy measurements have demonstrated that the spatial resolution of the process is better than 25 /spl mu/m. Time resolved photoluminescence measurements of the same sample have indicated a spatial resolution better than 20 /spl mu/m. Micro-Raman spectra were taken in a backscattering configuration in an increment of 2.5 /spl mu/m from the gold masked region.