Microstructural and compositional studies on multilayer elements based on low temperature cofired CaCu3Ti4O12-type ceramics

This work presents scanning electron microscope (SEM), energy dispersive spectroscopy (EDS) and X-ray photoelectron spectroscopy (XPS) analysis of polished surfaces of multilayer elements based on CaCu
3
Ti
4
O
12
, Bi
2/3
cu
3
ti
4
O
12
, Cu
2
Ta
4
O
12
and Bi
2/3
CuTa
4
O
12
ceramics, fabricated using LTCC (low temperature cofired ceramics) technology. Ceramic tape cast layers showed good cooperation with various electrodes made of commercial Ag, AgPd and Pt thick film pastes. EDS analysis revealed enrichment of grain interiors in copper, and grain boundaries regions in oxygen. XPS studies proved the presence of oxygen vacancies in all samples, and copper ions at two oxidation states (Cu
²⁺
and Cu
⁺
) in Bi
2/3
Cu
3
Ti
4
O
12
, Cu
2
Ta
4
O
12
and Bi
2/3
CuTa
4
O
12
layers.