High Density Evaporation Stack for OFETs

Enabling accurate deposition resolution

| |

The evaporation stack holds the source-drain shadow masks (sold separately) and substrates in close contact for thermal evaporation. This is crucial for device fabrication because the source-drain channel is the most critical feature on an OFET. For use with the and .

Specifications

The key component is the lower support, which is milled from a solid block of aluminum to provide high-precision recesses for individual shadow masks and substrates, and allows mixing-and-matching of shadow masks within a single evaporation.

Size	75 mm x 75 mm
Thickness	2 mm (exc. bolts)
Material	Lower support: milled aluminum Lid: stainless steel Magnetic sheet: vinyl-laminated polymer resin with ferrite powder
Substrate capacity	Square design: 12 substrates

Magnified example of high-density OFET source-drain mask within completed stack.

Architecture of an Evaporation Stack

The diagram below shows an deconstructed 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. This support has recesses in which individual masks are placed with the substrates placed on top of them. The lid is used to bolt everything together into a mechanically stable system that can be mounted in a deposition system at any orientation. Finally, a thick, low strength magnetic sheet is placed on to pull the in close contact with the substrates.

Technical Drawing

Dimensioned drawing of the square orientation lower support for the high-density OFET evaporation stack.

System Overview

Schematic diagrams showing how the high-density FET evaporation masks work together for:

A back-gate FET on a Si/SiO2 substrate.

A back-gate FET on any substrate.

A front-gate FET on any substrate.

For interdigitated FETs, the source-drain, active area, and gate masks need to be replaced with the corresponding versions.

Resources and Support

How to load the High density OFET stack

This video demonstrates how to load the high density OFET stack typically used to thermally evaporate (vacuum deposit) source-drain contacts. The video shows how to carefully place the evaporation masks into the substrate holder.