Heterogeneous‐Bonded Yb:YAG/SiC Disk Laser Device and Interface Stress Release

Yb:YAG lasers, known for their high pulse energy and high average power, are under active development worldwide. However, these systems face significant heat dissipation challenges. Herein, a thin‐disk Yb:YAG laser crystal is bonded to a SiC heat sink using adhesive bonding with benzocyclobutene (BCB) to efficiently remove waste heat from the gain medium. This approach alleviates the stringent requirements on surface roughness and high‐temperature treatments normally necessary for bonding. The interfacial region is characterized by using transmission electron microscopy combined with energy‐dispersive X‐ray spectroscopy. Tensile testing and scanning acoustic microscopy reveal that the Yb:YAG/SiC‐bonded wafers achieve a bonding strength of up to 8.4 MPa and a bonding efficiency of 82.1%. Furthermore, micro‐Raman imaging analysis is employed to assess the bonding interface stress, which is reduced by ≈44% through the incorporation of lateral outgassing surface trenches (LOTs). Detailed investigations of the temperature dependence of the stress show that the bonded devices with radially patterned LOTs exhibit enhanced thermal adaptation and stability, with stress levels dropping to as low as 297.50 MPa at 110 °C, thereby demonstrating the effectiveness of the stress‐release strategy.