Smart Cut Transfer of Wide-Bandgap Materials: The Case of Diamond

Abstract

Diamond exhibits a unique combination of exceptional properties, making it a highly attractive material for advanced technologies. Yet, these outstanding characteristics come at a cost: Diamond remains difficult to fabricate and is not readily available in large formats. In this context, the well-known Smart Cut layer transfer process—based on ion implantation and annealing—has been adapted for the first time to diamond. Turning a limitation into an advantage, the metastable nature of diamond allows for reducing the thermal budget required for cleavage. By finely tuning the implantation conditions, a buried sp2-rich layer can be created to serve as a fracture plane. Using this method, we successfully transfer an ~800-nm-thick diamond film onto a silicon substrate via metal bonding. After plasma etching of the residual sp2-rich layer, the transferred diamond preserves good crystalline quality, as confirmed by transmission electronic microscopy (TEM), electron energy loss spectroscopy (EELS), nanobeam diffraction, and Raman spectroscopy. While some implantation-induced point defects remain, they may be mitigated by a post-transfer annealing step. These results show that Smart Cut can be extended to ultrahard and chemically inert materials like diamond. This opens new perspectives for cost-effective, epi-ready diamond substrates on engineered hosts, paving the way for future high-performance electronics and quantum technologies.