DYNAMIC CONTROL OF REACTIVE MAGNETRON SPUTTERING - A THEORETICAL-ANALYSIS

The deposition of compound films by reactive magnetron sputtering can exhibit an unstable transition from a metallic target surface to one covered in reactino products. One solution to this is simply to "overpump" the deposition chamber so that the consumption of reactive gas by the pumps dominates the reactive gas consumption by the growing film. This involves additional expense at the construction stage and can be impractical in existing machines. Dynamic control of the reactive gas pressure can remove the instability and allow higher deposition rates and new film compositions to be achieved. Such dynamic control can exhibit oscillations about the control point. A theoretical analysis is presented here that gives a guide to system design and setting up. Practical results are given to show that with such a guide stable control can be achieved. © 1990.