Planar Spiral Micro-Inductor Based on Graphene/Cu Composite Film Conductive Coil Fabricated by MEMS Technology

Graphene has attracted extensive interest in the fields of electronics, sensors, composite materials and biological applications due to its excellent properties. In this paper, we present a planar spiral micro-inductor based on a graphene/Cu composite film conductive coil fabricated using microelectromechanical systems (MEMS) technology. The micro-inductor has a five-turn planar spiral coil structure, and the graphene films are prepared by electrophoretic deposition (EPD) and spin coating methods. The optimized EPD voltage and time as determined by scanning electron microscopy (SEM) and sheet resistance tests of graphene films are 10 V and 30 s, respectively. The surface morphology measured by atomic force microscopy (AFM) confirms that the EPD graphene film has a lower roughness than the spin-coated graphene film. The electrical performance test results show that the inductance of the EPD graphene/Cu micro-inductor is 515 nH at a frequency of 30 MHz, which is 48.4% higher than that of a pure Cu micro-inductor with the same structure, and the Q-factor is increased from 26.2 to 30.3. At the same frequency, the inductance of the spin-coated graphene/Cu micro-inductor is 498 nH, which is 43.5% higher than the pure copper micro-inductor, but the Q-factor is significantly reduced to 14.9 because of the excessive resistance. This research provides a feasible way to expand graphene in the field of micro-integrated electronic devices.