Adherence Enhancement of Metallic Film on PZT-Type Ceramic Using Nitrogen Plasma Implantation

Lead zirconate titanate (PZT)-type ceramics used as piezoelectric sensors have electrodes made by metallic film deposition on the ceramic substrate, which has low adherence on substrate surface. During the welding process in electronic component manufacture, the metallic film releases from surface due to the electrode delamination caused by the large difference in thermal expansion gradients between the film and ceramic. Delamination is a serious problem found in the manufacture of ceramic capacitors since the metallic electrode is split into several layers, leading to a component failure as the electrode is not in contact with the ceramic surface anymore. Therefore, in order to increase the film adherence on the ceramic it is proposed in this paper to treat the PZT samples covered with silver metallic films by means of plasma immersion ion implantation (PIII) technique using a high voltage 100-kV/1-μs stacked Blumlein pulser. By using this technique, it is shown that the mechanical adherence of the electrode metallic silver film is increased, which allows the welding process of terminals for the piezoelectric device manufacture without film release failure. Thermal stress relief treatment known as annealing process was also used in this paper as an alternative to the PIII method for increasing the film anchoring on ceramic substrate.