*Kenneth Scott Alexander Butcher, Vasil Georgiev, Dimka Georgieva, Meaglow Ltd, Ontario, Canada
Hollow cathode plasma sources are often sputter sources, however, for atomic layer deposition applications, gas based hollow cathode plasma sources operating at lower power density have become widely used. This has largely been because of reduced oxygen contamination evident with these plasma sources when depositing non-oxide films (e.g. J. Mater. Chem. C. 2 (2014) 2123) though other advantages include high radical flux and relatively low ion damage. Scalability is also often touted as an advantage of hollow cathodes, however plasma strike uniformity has been variable with past designs, and there are also concerns with sputter contamination when high power is used. Even at low power, there will be some level of contamination from any plasma source, the trick being to keep the level below what is acceptable for the process. The choice of cathode material can assist with this. For this paper we talk about our testing and development of aluminium hollow cathodes for deposition processes on silicon with a design that has proven to be scalable to a 12” diameter. Smaller 3” diameter cathodes of similar design were initially tested under various gas/plasma conditions using Langmuir probe measurements, and then the results were scaled to the 12” source.