De-bondable SiC-SiC 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 similar to 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 SiC-SiC. 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 similar to 1273 K is widely used.