Precious metal sputtering targets are usually available in thin foils. If only a very thin film is needed, buying a thinner target may be one way to reduce costs.
Reclaiming Spent Material
Most precious metals can be reclaimed. The remaining material can be sent back to be reclaimed, and the resulting credit can be applied towards future purchases. KJLC can take back many forms of reclaim. Terms can be found on our website.
Using UHV Grade Aluminum Foil on Chamber Walls
Lining the walls of the chamber with UHV grade aluminum foil can help capture precious metal overspray that does not end up on the substrate. This foil can be removed and turned in for reclaim, even when other non-precious metals are deposited in the same chamber. Shielding can also be periodically sent in to be cleaned and the precious metal content refined.
Thicker Walled E-Beam Crucible Liners
E-beaming requires a fill rate of no less than 30% at any time, often leading to more material being loaded than is actually needed for the desired films. Often times, a thicker walled crucible can be used to reduce the volume, allowing for less material to be loaded. Anytime the wall thickness changes, the beam pattern will need to be recalibrated. Any material left behind in the crucible can be reclaimed when deposition is complete.
Thermal Evaporation Source Selection & Load
Selecting the correct thermal evaporation source is important evaporating any material, but especially expensive materials like precious metals. For instance, gold alloys with the refractory metals. As such, we recommend using an alumina coated source to act as a barrier between the tungsten boat and molten gold. Reviewing the temperatures required prior to evaporation is also key. Platinum requires temperatures that make thermal evaporation not a viable method of deposition. Loading only as much material as needed to get the film required + 20% more as a buffer will also help reduce unused material left behind on the evaporation source.