Single-crystal-Ga2O3/polycrystalline-SiC bonded substrate with low thermal and electrical resistances at the heterointerface

A single-crystal β-Ga2O3 substrate was directly attached to a polycrystalline SiC (poly-SiC) substrate using a surface-activated-bonding method to enhance heat extraction from β-Ga2O3 devices. The effective thermal conductivity of the n+-Ga2O3/n+-poly-SiC bonded substrate and the electrical resistance at the heterointerface were characterized by using periodic heating radiation thermometry and analyzing vertical current–voltage characteristics, respectively. Small thermal and electrical resistances at the bonded interface demonstrated the strong prospects of the bonded substrates for applications to high-power vertical Ga2O3 devices.