Fatigue of organometallic chemical vapor deposited PbZrxTi1−xO3 thin films with Ru/Ruo2 and Pt/Pt electrodes

Abstract The relationships between switched and non-switched polarization with the number of switched cycles (fatigue) were investigated on organometallic chemical vapor deposited PbZr x Ti 1− x O 3 (PZT) thin films with primarily two different electrode combinations on oxidized silicon wafers. These electrode combinations were a ruthenium top electrode and a ruthenium oxide bottom electrode (abbreviated to Ru/RuO 2 ) and a platinum top electrode with a platinum bottom electrode (abbreviated to Pt/Pt). In comparison with Pt/Pt electrodes, PZT with Ru/RuO 2 electrodes shows improved endurance. To supplement the understanding of any physical effects that may occur during fatigue in the films, scanning Auger microprobe and scanning electron microscopy investigations were made on fresh and fatigued capacitors. These investigations suggest that Ru migrates from the top electrode into the PZT and forms channel-like structures locally in the PZT, causing the fatigue. Contrary to this no electromigration of Pt into PZT is observed. The different fatigue behavior observed for the two electrode systems might therefore be ascribed to different causes. The origin of the Ru migration is suggested to be related to the presence of a blocking layer at the PZT-top electrode interface.