Fabrication and studies of barrier layer capacitors

Barrier layer capacitors have been fabricated by introducing a thin CuO layer at the grain boundaries of semiconducting (Ba_0.8 Sr_0.2) (Zr_0.1Ti_0.9)O₃ ceramics. Three different methods are adopted in the fabrication of the barrier layer capacitors. The first is a single-firing method where CuO is segregated into the grain boundaries. The second method is a double-firing method, in which the CuO is diffused from the surfaces of the semiconducting ceramics at high temperature. The third method is also a double-firing process; however, the CuO is carried from the surface into the grain boundaries by a low-melting composition at lower temperature. The characteristics of the capacitors fabricated by the different methods are compared and studied