As the pioneer two-dimensional material with outstanding properties, graphene is still lacking a CMOS compatible handling process, both for growth and transfer. This restriction slows down the application of large-scale-high-quality monolayer graphene (MLG). The synthesis of wafer-scale single-crystal MLG has matured utilizing a single-crystal Cu(111) deposit epitaxially on c-plane sapphire as a growth template[1,2]. However, the non-straightforward intercalation base transfer process [3] becomes a bottleneck. Hence, an interfacial release layer between Cu and sapphire could provide an alternative route for the graphene transfer process.Here, we report on the synthesis of large-area multilayer graphene at the interface of epitaxial Cu(Ni)(111)/ Al2O3(0001) using atmospheric pressure chemical vapor deposition (CVD). The interfacial carbon layer (ICL) was synthesized by introducing CH4 and H2 gases in the CVD chamber at 1050°C, and characterized by micro-Raman spectroscopy, XRD, and AFM. Carbon layers with thickness up to 80nm were observed at the interface between 500nm thick Cu and Al2O3.The effects of the partial pressure of gases - PH2 and PCH4 – and template substrate on the growth dynamics were investigated systematically by optical microscopy and image analysis. The growth rate and deposition area of ICL are positively correlated with PCH4. In the Cu85Ni15(111) system, ICL coverage is significantly lower compared to Cu(111). This is attributed to the faster growth rate of a top surface MLG, which blocks the access of carbon into the interface of Cu(Ni)/Al2O3. A higher PH2 slows down the MLG growth, leading to a denser ICL deposition in both substrates.The growth mechanism of this ICL is also proposed as the result of two competing effects: 1. The high PCH4 environment drives the decomposed carbon species to the interface from the top surface by diffusion through the bulk of the catalytic metal. 2. The blockage of carbon access to the bulk of metal once the top layer MLG is closed.After process optimization, the ICL could be synthesized simultaneously with top layer high-quality CVD MLG. In the future, this process could provide opportunities to enable CMOS compatible large-scale-high-quality MLG transfer. K. Verguts et al., ECS J. Solid State Sci. Technol., 5, Q3060–Q3066 (2016).M. Huang et al., ACS Nano, 12, 6117–6127 (2018).K. Verguts et al., ACS Appl. Mater. Interfaces, 9, 37484–37492 (2017).