Abstract
Several simulations were performed in order to investigate the effects of the device size of SiC ceramic thermistors of which materials have nonuniform microstructure on their electrical properties quantitatively. The boundary potential model and the energy band model were used to express the electrical characteristics of the grain boundaries in the simulations. These simulations show that the reduction of device size tends to widen the variation of the resistivity and the variation of the B constant. Furthermore, it was found that the device size reduction tends to decrease the average of the resistivity and average of the B constant. These are explained by the percolation theory. The uniformalization of the microstructure and/or the increase of the number of grain boundary between the electrodes are necessary for the manufacturing of the devices that have uniform electrical properties.
