High-Frequency-Discharge Trimming of RuO2-Based Thick-Film Resistors-Part II: Mechanism of Resistance Change

Mechanism of resistance change by high-frequency-discharge trimming has been investigated for RuO2 glaze resistors. As a result, it is found that the resistance of RuO2 glaze resistors eventually increases when subjected to the discharging over an extended period because of structural damage of the resistor films. As for RuO2 · glass resistors, the resistance increases with the increasing discharge time, but as for Ag- or Nb-doped RuO2 · glass resistors, the resistance decreases during the initial stage of the discharging. The main cause for the resistance reduction is the increasing concentration of Ag atoms in the trimmed area in the case of Ag-dopad resistors, and in the case of Nb-doped resistors the change in valence value of Ru, i.e., Ru4+ -> Ru3+.