Wafer and epilayer improvement for integrated optics devices on InP: the ESPRIT project 2518

Abstract

Ga _x In_1−x As _y P_1−y alloys lattice matched to InP substrates are currently used to fabricate optoelectronic and integrated optics devices. To achieve devices with high performances and high fabrication yield, the uniformity and reproducibility of the Ga _x In_1−x As _y P_1−y epitaxial layers (composition, thickness, doping, etc.) have become key parameters. These problems have been addressed in the frame of ESPRIT project 2518 and are presented in this paper. Several aspects have been considered starting from the optimization of InP substrates, the MOVPE growth of uniform GalnAsP layers, the material characterization to the validation of material uniformity on passive optical waveguides. Both scanning photoluminescence analysis and waveguide losses measurements performed on 2 inch wafers with a high lateral resolution have shown that high quality uniform GalnAsP layers can be obtained reproducibly on 2″ InP substrates using a commercially available LP-MOCVD growth process. In particular, more than 60% of 36 mm long, 3μm wide and 100μm spaced rib waveguides exhibit losses below 0.8dBcm⁻¹.