RuO2/Ru electrode on Si3N4/Si substrate for microelectromechanical systemsdevices based on Pb(Zr1-xTix)O-3 film and surface micromachining

RuO2/Ru conducting films were deposited on low stress Si3N4/Si substrates b y reactive r.f. sputtering deposition at a substrate temperature of 400 deg rees C to introduce a new bottom electrode for microelectromechanical syste m devices based on a Pb(Zr1-xTix)O-3 film and a surface micromachining tech nique with high temperature processes. X-ray diffraction and scanning elect ron microscopy measurements after heat treatment at 700 degrees C were cond ucted to investigate structural stability of the RuO2/Ru films, which showe d no silicide and silicon oxide formations by the heat treatment. Interfaci al structures of the film with the heat treatment were similar to those of the as-deposited films. The surface of the film with the heat treatment con sisted of larger grains than those of the as-deposited film. Rutherford bac kscattering spectrometry and Auger electron spectroscopy showed no interfac ial reactions between the RuO2/Ru and the Si3N4 In order to investigate the feasibility of the RuO2/Ru as a bottom electrode, Pb(Zr0.53Ti0.47)O-3 film s were deposited by metalorganic decomposition. After deposition of a Pb(Zr 0.53Ti0.47)O-3 film at 700 % for 30 min, the interface structure between th e RuO2/Ru and the Pb(Zr0.53Ti0.47)O-3 film showed no interface reactions. T he electrical properties of the PZT film on the RuO2/Ru were not changed be fore and after an HF etching to make an air gap, even though the piezoelect ric coefficients on the RuO2/Ru were lower than on the Pt/Ti. Therefore, th e RuO2/Ru conducting film could be used for a bottom electrode on the Si3N4 /Si for a microelectromechanical system device based on a Pb(Zr1-xTix)O-3 f ilm and a surface micromachining technique with high temperature processes.