Low-Density OFET Fabrication System Overview and Schematic
The below diagram shows an exploded view of how the evaporation stack fits together. At the base of the system is the lower support which prevents the thin and flexible shadow masks from warping. The shadow masks are then placed on top of the lower support. Above this, the substrate support holds the substrates in alignment with the mask before a low strength magnetic sheet is placed on to pull the shadow mask in close contact with the substrates. Finally the lid is used to bolt everything together into a mechanically stable system that can be mounted in a deposition system at any orientation.
Lid: Holds the substrates and magnetic sheet in position
Magnetic sheet: Pulls the thin and flexible shadow mask into close contact with the substrate
Substrates: Up to twelve substrates per mask (sold separately)
Upper support: Holds and aligns the substrates in position above the shadow mask
Shadow mask: Interchangeable shadow masks with varying designs. Five OFETs per substrate
Lower support: Provides mechanical support to the thin and flexible shadow masks
The low density fabrication system has four different masks available to allow the fabrication of devices in any geometry (top/bottom gates and top/bottom source-drain). The diagrams below show the features on each of the individual masks as well as how they fit together on a substrate.
Note that silicon oxide substrates do not need a gate mask which simplifies fabrication, however the use of a gate mask with quartz-glass substrates can allow lower operating voltages and lower parasitic capacitance.