LOW-TEMPERATURE GROWTH OF 850-NM QUANTUM-WELL MODULATORS FOR MONOLITHIC INTEGRATION TO VERY LARGE-SCALE INTEGRATED ELECTRONICS ON GAAS

We report a new, low-temperature process for monolithically integrating 850 nm modulators to pre-existing very large scale integrated GaAs electronics. We find pristine GaAs surfaces form below 400 °C in the presence of energetic protons generated by an electron cyclotron resonance plasma. While 850 nm superlattices grown at 430 °C exhibit nearly perfect lattice structure when examined by x-ray diffraction, nonradiative centers are detected with photoluminescence. Transmission spectroscopy reveals the excitons deteriorate too rapidly under bias voltage to fully utilize the quantum confined Stark effect. Efforts to reduce nonradiative trap generation and improve modulator performance under low-temperature growth appear more feasible when growth is performed under tightly controlled stoichiometric conditions than with arsenic pulsed layer molecular beam epitaxy methods.