MOUNTING OF HIGH-POWER LASER-DIODES ON DIAMOND HEATSINKS

This work describes the mounting of commercial 1 W laser diodes solder ed on chemical vapor deposition (CVD) diamond heatsinks using Au(80)Sn (20)-solder. With a standard heatsink metallization, the laser diode s uffers under high stress. This can be seen in the power-current charac teristic and the spectrum as well as in the near and farfield beam pat tern. With a modification of the heatsink metallization layer, it was possible to obtain a reproducible mounting process. We compare the ele ctrical and optical characterization of the typical standard heatsink metallization with the modified metallization. So we are able to quali fy the mechanical stress in the laser diode. For a better understandin g of the modified metallization SEM and EDX analyses are performed. Fo r the quantification of the stress an analytical model is used to comp ute the maximal shear, tensile, and peel stress. Furthermore, the qual ity of the bond interface is investigated with high resolution X-ray m icroscopy. No voids are found. Additionally, the results of a standard burn-in and the first accelerated aging tests to prove the reliabilit y are presented.