Influence of the contacts and firing process on the properties of thick film resistors on alumina and dielectrics

This paper describes the behaviour of thick film ruthenium resistors when printed and fired onto standard 96% alumina substrates and onto alumina substrates covered with a dielectric film during long-term thermal ageing. It was observed that the behaviour of the resistors on alumina and dielectric depends upon the firing process of the resistors and the kind of terminations. An analysis of the effects of thermal ageing was made as well as some SEM observations of diffusion processes between the resistor and its terminations.