Ageing Mechanisms and Stability in Thick Film Resistors

Thermal ageing experiments on various thick film resistor systems have shown that resistance change is caused by a number of different mechanisms with different time dependences. Three distinct types of behaviour have been identified: corrosion due to ambient attack; diffusion through resistor interfaces with conductor terminations or through the resistor top surface; and stress relief within the bulk of the resistor. Wherever possible the dominant mechanism has been identified and the activation energy and time dependence of the ageing process have been determined.