Thermomechanical performance of high-power laser diode arrays using a liquid metal-diamond particle hybrid composite bonding layer

The beam quality of the high-power laser diode arrays (HPLDAs) is often compromised by the thermomechanical stress resulting from mismatched coefficients of thermal expansion among the packaging materials. In this study, a paste-like liquid metal-diamond particle (LM-DP) hybrid composite is proposed as an alternative bonding layer to traditional solder. Finite element analysis reveals that packaging with the LM-DP layer achieves a nearly uniform stress distribution (stress fluctuation less than 2.62 MPa) and eliminates 99.9% of the interfacial shear stress compared to traditional solder layers under the idealized simulation conditions. Additionally, this packaging method reduces the smile effect under standard operating conditions by approximately 40%. The results indicate that when the diamond particle content reaches 50%, both the chip junction temperature and mechanical stress are minimized. While increasing the bonding layer thickness further may lead to a higher smile effect, this will be alleviated by thermal resistance. This work demonstrates a proof-of-concept simulation and a theoretical feasibility study of applying the paste-like thermal interface materials for low-stress packaging, offering significant potential for improving the beam quality and brightness of HPLDAs.