A New PLZT Dielectric for Use in Characteristic X7R Multilayer Ceramic Capacitors

Abstract

A low firing-temperature lanthanum-modified lead-zirconate titanate (PLZT) dielectric has been developed to meet EIA Characteristic X7R specifications. Multilayer ceramic capacitors made from this material were sintered below 1100°C and exhibited the following electrical characteristics: dielectric constant, 2050; dissipation factor at I kHz, 1 Vrms/mil of dielectric <0.25 percent; BX temperature-voltage characteristic, 90-100 V/mil; insulation resistance at 25°C, 50 V/mil, > 106 <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\Omega</tex> -F, and at + 125°C, 50 V/mil, > 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">5</sup> <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">\Omega</tex> -F. Long-term life test at 2 x rated voltage made very little change in any of the electrical properties.