CVD-based, photolithographically patterned, highly-sensitive graphene Hall element on hexagonal BN

Graphene is known to have a high carrier mobility, and the carrier density can be minimized at the charge neutrality point (CNP). Because such features are suitable for Hall sensor measuring magnetic field, we examined the possibility of graphene Hall element (GHE) as a highly sensitive magnetic sensor. For the high-throughput production of GHE in the future, the material synthesized by a chemical-vapor-deposition (CVD) method and the fabrication processes based on photolithography were adopted to show its mass-production feasibility. Specifically, the CVD synthesized hexagonal BN (hBN) was tested as a protection layer of graphene from extrinsic doping driven by SiO$_{2}$ substrate, which causes the shift of CNP. In addition, post annealing sequences were also included between each step, such as the hBN attachment on SiO$_{2}$ and the graphene transfer on hBN/SiO$_{2}$ substrate followed by the PMMA removal. From this work, we can get minimum magnetic resolution around 10 mG/Hz$^{0.5}$ at 300 Hz.