Introduction Aluminum nitride has a combination of useful properties that recommend it for a variety of applications. - It is a strong piezoelectric material. This makes is useful in filters (like SAW devices) and generally in sensors and transducers. - It is employed in MEMS devices due to the above functionality. - It is an excellent thermal conductor – better than many metals. At the same time, it is an electrical insulator. This makes it ideal for heat dissipation in electronic devices. - As it is electrically non-conducting, it is useful as an insulation layer in devices, in capacitors, as a passivation coating, or buffer layer. - It is chemically stable and hard, serving as a protective layer such as corrosion resistant coatings. This material is still emerging in many application areas, so processes for thin film deposition are called for. Sputtering is often utilized for this task. Aluminum nitride has a notoriously low sputtering yield, making deposition from ceramic targets impractically slow. Bulk aluminum nitride is also expensive, so fabricating targets for such a process adds to cost. Reactive sputtering from an aluminum target in a nitrogen-containing sputter gas is a faster process, using more affordable starting material (10x cheaper). We share here recipes we’ve developed using three different reactive processes: RF, DC, and HiPIMS sputtering. The goal is to provide a starting point for process recipes that anyone working in PVD can use.
