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Source-Drain Deposition Mask, Low Density

Substrates and Fabrication

Product Code E291
Price £260 ex. VAT

Shadow masks for deposition of source drain contacts. Designed for use in the low density evaporation stack with our standard sized substrates of 20 x 15 mm. Each mask will work with up to 12 substrates, each with five OFETs to produce a total of 60 devices in a single evaporation.


Linear channels of width 1 mm with two designs available of either five identical channel lengths of 30 μm or variable channel lengths of 30, 40, 50, 60 and 80 μm (one per substrate)

Number of OFETs 60 (5 per substrate)
Channel length E291: 30 μm
E292: 30, 40, 50, 60, 80 μm (one each per substrate)
Channel width 1 mm
Contact pad size 1 mm x 1 mm
Mask thickness 35 µm
Channel bar tolerance ±10 µm
Mask material Hard electroformed nickel

*E291/E292 yield of working devices is 90% (54/60).

OFET evaporation mask (low density) technical drawing
Schematic of the the whole mask (see source-drain evaporation stack for details of how it fits with other layers).
OFET substrate mask dimensions (Low density) variable channel length
Key dimensions for the small features on E291. The dotted line shows the outline of a substrate for reference.
Low density OFET shadow mask (variable channel length)
Optical image of the variable width source-drain evaporation mask.
Low density OFET shadow mask (constant channel length)
Optical image of the 30 µm width source-drain evaporation mask

The mask is designed in such a way that during the deposition of the gate electrodes on the corner of the substrate the metal should cover the edge of the substrate as well. This ensures conductivity between the metal electrodes and the p-doped silicon. If you find the edges of the substrate not to be conductive you must scratch the edges of the substrate to remove the insulating silicon oxide in correspondence with the corner where the gate electrode will be deposited.

Prefabricated OFET: gate electrode details
Prefabricated OFET: details of the gate pad/doped silicon electrical contact.
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