Thermal stability of evaporated Pd, Pt and Rh films as reaction barriers to Au-Sn solder was studied for the application to flip-chip optoelectronic integration. Sn in the solder diffused preferentially into a barrier metal uniformly to produce more stable intermetallic phases for all three metals. Pt and Rh exhibited sufficiently samll interdiffusion coefficients with high activation energies in the temperature range of device operation (Pt: 1.35 eV, Rh: 1.95 eV). This result demonstartes the usefulness of Pt and Rh in practical flip-chip integrated circuit fabrication. Aging test was conducted on flip-chip GaInAs/InP p-i-n photodiodes with Au-Sn/Pt metallization and no severe degradation was observed over 3400 h at 180 ° C. The same metallization techniques were applied in the fabrication of 10 Gbps optoelectronic integrated receivers as well as quad p-i-n photodiodes for coherent optical receivers.