Robust BME Class-I MLCCs for Harsh-Environment Applications

For applications at temperatures of 150°C or above, such as in automotive under the hood electronics and power electronics, a robust dielectric material is necessary for capacitors. In traditional X8R products [Electronic Industries Alliance (EIA) specification, AC/C within ±15% between -55°C and +150°C compared to that at 25°C], the dielectric material is designed for applications up to 150°C. However, at temperatures above 150°C, these typically suffer from degradation of reliability performance and severe reduction in capacitance, particularly under dc bias conditions. Recently, a Class-I dielectric material has been developed using nickel electrodes for high-temperature application up to 200°C. Due to its linear dielectric nature, this material exhibits highly stable capacitance as a function of temperature and voltage. Multilayer ceramic capacitors made from this material can be qualified as X9G with robust reliability. This paper will report electrical properties and reliability test data on these Class-I ceramic capacitors at temperatures ≥ 150°C. In addition, test data from D - E curves and energy density measurements will be reported along with a discussion of possible mechanisms behind the robust reliability of this material.