Measurement of the Tunneling and Hopping Parameters in RuO2 Thick Films

Thick film resistors containing a mixture of ruthenium oxide (RuO2) and lead borosilicate (Pb5B2SiO10) have been produced on alumina [(Al2O3)·96(MgO)·04] substrates. The temperature coefficient of resistivity (TCR) of these films has been measured for different particle size and concentration (weight percentage) of the conductor particles. The TCR was found to be a function of temperature in all the films included here. From the measured values of negative TCR the tunneling parameter α and hopping parameter β were determined. These results suggest that hopping is important for the low concentration films. For films with positive TCR only parameter α could be determined. The parameter α increased but the parameter β decreased with temperature for the present films.