Polishing Diamond Substrates using Gas Cluster Ion Beam (GCIB) Irradiation for the Direct Bonding to Power Devices

Gas cluster ion beam (GCIB) was employed to polish CVD diamond substrates for the direct bonding to power devices. After the coarse and fine polishing, the surface roughness Ra of diamond was reduced from 334 nm to 0.5 nm. The polished diamond substrate was successfully bonded to GaN at room temperature by surface activated bonding (SAB) method with a Si nano-layer.