Improvement of Cermet Film Resistors
Original Publication Date: 1987-Mar-01
Included in the Prior Art Database: 2005-Feb-01
Cermet materials are used as thin film resistors. After processing, the cermet resistors are subjected to a "stress test" of many hours exposure to an environment of elevated temperature and humidity. Some cermet resistors show large increases in resistance during the stress test which cause the resistors to fall out of specifications. Increases in resistance during this test have been correlated with higher values of the temperature coefficient of resistivity (TCR), which is measured before the stress test. A technique is described for providing a stable Cr-Si cermet structure having reduced resistance change during annealing. A cermet of nominal composition 60 at.% chromium (Cr) and 40 at.% silicon monoxide (SiO) is sputtered onto an alumina substrate at nearly 125oC to give an average thickness of 500 Ao .