WAVELENGTH TUNING IN STRAINED-LAYER INGAAS-GAAS-ALGAAS QUANTUM-WELL LASERS BY SELECTIVE-AREA MOCVD

Selective-area growth and regrowth using conventional atmospheric pressure metalorganic chemical vapor deposition is investigated for wavelength tuning in strained layer InxGa1-xAsGaAs-AlyGa1-yAs quantum well lasers. Growth inhibition from a silicon dioxide mask is the mechanism used for the selective-area growth rate enhancement. By varying the width of the oxide stripe opening, differences in the growth rate yield different quantum well thicknesses, and hence different lasing wavelengths for devices on the same wafer. Both two- and three-step growth processes are utilized for selective-area epitaxy of strained layer InxGa1-xAs-GaAs quantum well active regions, with lasers successfully fabricated from the three-step growth. Scanning electron microscopy and transmission electron microscopy indicate that the absence of an oxide mask during AlyGa1-yAs growth is essential for successful device operation. A wide wavelength tuning range of over 630 angstrom is achieved for lasers grown on the same substrate.