LARGE-AREA WAFER PROCESSING FOR 0.78-MU-M ALGAAS LASER-DIODES

Large-area wafer processing for buried-ridge loss-guided inner-stripe AlGaAs laser diodes (LD's) has been developed for the first time. High uniformity of ridge waveguides on a 3-in wafer is realized by introdu cing selective wet etching, The standard deviations of the ridge width and the remaining p-cladding layer thickness on either side of the ri dge, which have a great influence on the device characteristics, are 0 .07 mu m and 0.01 mu m, respectively, As a result, good uniformity of laser characteristics has been obtained, far example, the distribution of full width at half maximum angles of far-field pattern in the dire ction parallel to the junction plane (theta(//)) is only 0.22 degrees (1 sigma) for 1000 chips across a 3-in wafer.