Reliability of bonding interface in high power diode lasers

With the rapidly increasing applications of high power laser diode(HPLD) in extreme environments, the reliability of bonding interface has become one of the critical bottlenecks affecting the HPLD's performance and lifetime. In this work, failure behavior and lifetime of a single-bar CS-packaged HPLD under -55-125℃ thermal-shock were analyzed by finite element method(FEM). Based on Anand constitutive model and Darveaux energy accumulation theory, the reliability of indium bonding layer on the edge and at the central position after the themal-shock was compared. It shows that the bonding interface on the edge has the highest stress (0.042 5 GPa) and lowest lifetime (3 006 cycles), in other words, the edge is the riskiest element of the bonding interface. In addition, the lifetimes of three kinds of bonding layers on the edge, including indium, 80Au20Sn and nanosilver paste, were simulated to be 3 006, 4 804 and 4 911 cycles, respectively. The results show nanosilver paste and 80Au20Sn have longer lifetimes and better reliability, which are better bonding materials in the packaging of high power laser diodes used in extreme enviroments.