High-Temperature Adhesive Bonding of 4H-SiC Substrates

This study explores the application of Polycarbosilane (PCS) as an intermediate adhesive bonding technique for 4H-SiC substrates aiming to overcome the challenges of producing high-quality and cost-effective substrates for high-power electronics. Thin layers of PCS mixed with m-xylene and AIBN (azobisisobutyronitrile) were deposited onto 4H-SiC substrates via a spin coating. For demonstration purposes, these coated 4H-SiC substrates were then bonded with another 4H-SiC substrate. A defect-free, high-temperature stable bond is facilitated by annealing at high temperatures. Effusion measurements were conducted to characterise the PCS thin films and examine the organic-inorganic transitions and the resulting outgassing at high temperatures. SEM analysis confirmed the uniformity of the bonded layer. These results demonstrate PCS’s potential in high-temperature applications and will stimulate further research exploring doped SiC bonding layers and their electrical properties.