Realization of a Graphene/PMMA Acoustic Capacitive Sensor Released by Silicon Dioxide Sacrificial Layer

We report the realization of an acoustic capacitive microphone formed by graphene/poly(methyl methacrylate) (PMMA). It is first time that ultra-large graphene/PMMA membrane suspended fully over cavity has been fabricated releasing silicon dioxide sacrificial layer underneath membrane. The novelty in fabrication method etched hydrogen fluoride vapor from back partly substrate. Using new process, membrane, with a diameter to thickness ratio 7800, 2 ?m air gap. spacing minimum gap graphene-based microphones which have reported so far. static deformation after estimated be 270 nm. aspect membrane’s its around 13,000, shows few millimeters can transferred and substrate relatively small layer. dynamic behavior device under electrostatic actuation characterized. response measured, sensitivity observed ?47.5 dB V (4.22 mV/Pa) ± 10%. strain 0.034%.