Different approaches for controlling a reactive HIPIMS sputter process

Aluminum oxide is used in many applications as hard coating, for example on cutting tools. In addition to this, alumina has very good insulating properties, which makes it suitable for sensor applications on metal substrates. In these applications, the main challenge is to produce defect free thin films under economical aspects. Up to now, many alumina deposition processes are based on RF sputtering, typically with low deposition rates. Reactive sputtering from an aluminum target in an oxygen/argon atmosphere leads to higher deposition rates but makes a process control essential to sustain a stable process. HIPIMS offers a tool for tailoring the film properties, but the reactive process control is more challenging. Therefore, investigations were carried out using different types of a reactive process control to stabilize the process. In this study, the use of two different feedback systems, a Plasma Emission Monitor and a Pulse Pattern Controller was investigated in combination with Deep Oscillating Magnetron Sputtering and High Power Impulse Magnetron Sputtering, even superimposed with MF.