EFFECT OF CONDUCTION PARTICLE-SIZE ON LAB6 THICK-FILM RESISTOR

In order to obtain guidelines to develop a thick film resistor (TFR) fireable in an N2 atmosphere and covering a wide practical range of sheet resistivities, i.e. 10-10(6) OMEGA/open-square-box, the microstructures of TFRs were observed, the sintering behaviour of the conduction particles and glass was analysed and the particle size effect on the formation of the conduction path was simulated. Through these investigations, conductive material properties which influence the characteristics of the TFR have been found. (1) As conduction particles fireable in N2, LaB6 particles have suitable properties such as poor sinterability and good wettability with glass. (2) Particle size also has a large effect on the characteristics of the TFR, and it is necessary to use LaB6 ultrafine particles (UFPs) as conduction particles to cover a wide range of sheet resistivities. Using UFPs with specific surface areas of 8.9 and 83.0 m2 g-1, we found the possibility of developing TFRs fireable in N2 with resistivities of 10-10(6) OMEGA/open-square-box in the LaB6-glass system.