Dependence Of Composition And Microstructure Of Ruox Films On Target Status And Substrate Temperature In Reactive Sputtering Deposition

Ruthenium oxide films were deposited on Al2O3 (0001) and (<1(1)over bar 02>) substrates using reactive sputtering under two different target surface conditions. Films grown when the surface of the target was metallic ruthenium (metallic-target) showed a Ru:O ratio of 1:2.0+/-0.05 as determined by Rutherford backscattering spectrometry. At elevated deposition temperatures, these films aligned with the substrates as RuO2 (100) parallel to Al2O3 (0001) and RuO2 (101) parallel to Al2O3 (<1(1)over bar 02>). Films deposited when the target surface was fully oxidized (oxidized-target) exhibited a Ru:O ratio of 1:2.5+/-0.05 and displayed an oriented crystalline structure even at room temperature. The resistivity of the RuO2.5 films was 75 mu Omega-cm and was independent of temperature between 5 and 300 K. Possible causes of this behavior are discussed.