Towards Controlled Transfer of (001) β-Ga₂O₃ to (0001) 4H-SiC Substrates

We demonstrate successful surface blistering of He-implanted (001) β-Ga 2 O 3 substrates, bonding to (0001) 4H-SiC, and initial results towards large-area transfer of (001) β-Ga 2 O 3 to 4H-SiC. Surface blistering of unbonded, implanted substrates is an important indication of successful exfoliation and transfer of films, which is achieved by initiating He bubble nucleation during a low temperature anneal followed by bubble growth at a high temperature anneal. Prior to annealing, implanted substrates were bonded to (0001) 4H-SiC at room temperature using a thin ~5 nm Ti interlayer. However, the β-Ga 2 O 3 substrate did not wafer split from the bonded structure after annealing. Instead, small area transfers up to ~200 μm were achieved (~7% of the total bonded area transferred while the entire structure remained bonded). Further optimization of implant parameters is underway. These are promising results towards achieving large wafer-scale (001) β-Ga 2 O 3 composite wafers suitable for β-Ga 2 O 3 devices with efficient thermal management characteristics.