Aluminum Evaporation
Thermally evaporating aluminum presents several challenges due to incompatibilities with the materials that commonly comprise deposition boats/crucibles.
During the initial melt – the surface tension of the liquid metal will cause it to wet the ceramic walls and ‘wick’ up the crucible or boat.
After deposition – as the molten aluminum cools – the lower surface tension of the solid metal causes it to recede, stressing the walls of the crucible and often causing it to crack.
Preventing Crucible Cracking
One common method of preventing crucible cracking is to empty the source of all molten aluminum by evaporating it dry after each deposition; however, this requires a vent and material loading cycle after each aluminum layer, which is not suitable for load-lock or cluster-integrated systems, and is very time-consuming.
Aluminum can wick all the way to the copper posts, causing a short. When the boat being used is made from refractory metals, the aluminum alloys to form brittle compounds that crack easily. It is common to see metal boats break after only 1-3 depositions.
To make sure you get the most out of your materials, Angstrom Engineering® has developed propriety solutions to these common problems.
For Standalone Systems
For standalone systems without a load lock, our proprietary evaporation source is capable of up to about 100 aluminum depositions without degradation of the source or film performance. You can find more information on this source here.
For Cluster or Load Lock Integrated Systems
For cluster or load lock integrated systems, we have developed a solution using an automated material dispensing system. To learn more about our aluminum evaporation solutions or to see a demonstration, please contact us.
Dr. Stephen Forrest
University of Michigan
From the time it was delivered, this laboratory system has performed nearly flawlessly, arguably extending our capabilities well beyond those currently attainable by any organic thin film laboratory in the world. I attribute the success of this entire system to the excellence of the engineering as well as the cooperative nature of the Angstrom team in taking our best designs and making them better during the system construction process.