Direct Wafer-Scale CVD Graphene Growth under Platinum Thin-Films

Since the transfer process of graphene from a dedicated growth substrate to another substrate is prone to induce defects and contamination and can increase costs, there is a large interest in methods for growing graphene directly on silicon wafers. Here, we demonstrate the direct CVD growth of graphene on a SiO₂ layer on a silicon wafer by employing a Pt thin film as catalyst. We pattern the platinum film, after which a CVD graphene layer is grown at the interface between the SiO₂ and the Pt. After removing the Pt, Raman spectroscopy demonstrates the local growth of monolayer graphene on SiO₂. By tuning the CVD process, we were able to fully cover 4-inch oxidized silicon wafers with transfer-free monolayer graphene, a result that is not easily obtained using other methods. By adding Ta structures, local graphene growth on SiO₂ is selectively blocked, allowing the controlled graphene growth on areas selected by mask design.