Strategies for high rate reactive sputtering

Abstract

High rate reactive sputtering of heavily insulating dielectrics such as Si 3N 4 and TiO 2 is a key requirement for economic production of complex coating designs. Two approaches for achieving enhanced deposition rates for TiO 2 are contrasted. The use of closed loop process control through plasma emission monitoring has been demonstrated utilizing both DC and mid-frequency AC sputtering sources. Alternatively, high rate deposition of TiO 2 has been demonstrated via deposition from a sub-stoichiometric ceramic TiO 2 target, also utilizing DC and AC deposition. The use of mid-frequency AC is required to eliminate deposition non-uniformity due to insulating build up on anode surfaces. Data on deposition speeds, optical properties, long term deposition rate and uniformity stability are presented for both processes.