Effect of RuO2 crystallinity and particle size on electrical property of LTCC resistors

Abstract

The crystallization and sintering process of RuO[Formula: see text]xH2O nanoparticles have been investigated in this paper. The effect of RuO2 crystallinity and particle size on the sheet resistance of RuO2-based resistor paste after being co-fired with CaO–B2O3–SiO2 green tapes has been reported. The results show that the nanoparticles are not fully crystallized below 600[Formula: see text]C, and the effect of high-density defects, such as grain boundaries and dislocations on the residual resistance ([Formula: see text] of RuO2 particles, is significant. So, the sheet resistance decreases with the increase of crystallinity and the weakening of electron wave scattering. Above 600[Formula: see text]C, the effect of crystal imperfections on [Formula: see text] is greatly weakened. However, the number of conductive chains formed in co-fired resistor decreases with the increase of particle size, thus the sheet resistance gradually raises. When the dwelling time is increased to 3 h, the RuO2 is mostly crystallized and the effect of crystal imperfections on [Formula: see text] is negligible, and the sheet resistance mainly depends on particle size of RuO2. Using RuO2 particles with low crystallinity, small size and narrow particle-size distribution as conductive phase is expected to solve the problem of poor sheet resistance uniformity in high resistance paste for LTCC application.