ELECTRICAL CHARACTERISTICS OF SNO2-BASED THICK-FILM RESISTORS LOADED WITH SNCL2

Thick film resistive pastes using SnO2 as a functional material are reported (S. H. Bhide, N. Vittal, C. R. Aiyer, R. N. Karekar and R. C. Aiyer, Int. J. Hybrid Microelectron., 11 (2) (1988) 36) to give a high sheet resistivity of 1 Mω/□. In this paper the effect of SnCl2 loading on SnO2 paste is reported. By increasing the proportion of SnCl2 in the SnO2 paste, variation in sheet resistivity ρ{variant}s is obtained down to a minimum of 5 kω/□. The temperature coefficient of resistance (TCR) is in the range from -3650 to -950 ppm °C-1. The ρ{variant}s and TCR values are also optimized by changing the firing temperature (in a normal atmosphere) in the range 550-750 °C. The minimum ρ{variant}s and TCR values are obtained at 725 °C. Material characterization using X-ray diffraction reveals additional phases, particularly after 45%-50% loading with SnCl2, when ρ{variant}s decreases rather abruptly. Aging studies of the resistors, at room temperature over a period of two months, show an initial change of about 12% and then stable values after a period of 25-30 days. © 1990.