Thick-film resistors with high negative TCR on alumina and LTCC substrates

Abstract

The electrical and microstructural characteristics of NTC thick-film resistors, fired either on alumina or cofired on "green" LTCC substrates are compared. The NTC resistors, fired on LTCC (as compared to resistors on alumina substrates), have higher sheet resistivities, higher beta factors, and also significantly higher noise indices. SEM and EDX analysis indicated the interaction between NTC and LTCC materials, mainly the diffusion of the glass phase from the LTCC substrate into the NTC resistor.