De-bondable SiCSiC wafer bonding via an intermediate Ni nano-film

In this study, a de-bondable wafer bonding method for silicon carbide (SiC) that can sustain rapid thermal annealing (RTA) at ∼1273 K has been realized. Two SiC wafers were bonded via an intermediate nickel (Ni) nano-film at room temperature without any pressure, which was characterized as a seamless and robust bonding. After the RTA process, the strength of the bonding interface was dramatically decreased and the de-bonding could happen at the interface during pulling test. Both of the mechanisms of bonding and de-bonding have been investigated through interface analyses. The sufficient atomic diffusion between two deposited Ni nano-films together with the interfacial mixing between amorphous SiC and the Ni nano-film contribute to the strong bonding of SiCSiC. The interfacial precipitation of layered carbon material parallel to the SiC substrates is assumed to be the reason of the interface weakening and de-bonding after annealing. It is believed that the further development of this bonding and de-bonding technology will advance thin SiC device fabrication, where the RTA process at ∼1273 K is widely used.