Graphene Field-Effect Transistors
The device consists of CVD-grown monolayer graphene transferred onto pre-patterned contacts and passivated with a silicon oxynitride stack. CVD graphene enables graphene production on catalyst foils up to 100mm × 100mm in size, allowing to fill a silicon wafer with a few transfers. Fabrication can be performed on 200-mm wafers, where up to hundreds of chips can fit. Each chip contains several groups of transistors. Within each group, transistors have one common source electrode and each one has an individual drain electrode. All groups share a common gate electrode. Silicon oxynitride passivates the entire surface except the transistor channels and the contact pads. The chips can come either as a diced wafer or wire-bonded to PCB mating with board-to-board connectors. These chips are prepared for biosensing studies using an aqueous electrolyte as the gate.
GFET Measurement Data
Representative transconductance and Y-function data for GFETs in a bottom-gate configuration, chip 13.292 produced by INL. The Y-function methodology was used to determine mobility values (assuming oxide thickness of 70 nm), as described in:
G. Ghibaudo, “New method for the extraction of MOSFET parameters”, Electronics Letters 24(9), 543–545 (1988), DOI:10.1049/el:19880369