Towards metal electrode interface scavenging of rare-earth scandates: A Sc2O3 and Gd2O3 study

Amorphous Gd"2O"3 and Sc"2O"3 thin films were deposited on Si by high-pressure sputtering (HPS). In order to reduce the uncontrolled interfacial SiO"x growth, firstly a metallic film of Gd or Sc was sputtered in pure Ar plasma. Subsequently, they were in situ plasma oxidized in an Ar/O"2 atmosphere. For post-processing interfacial SiO"x thickness reduction, three different top metal electrodes were studied: platinum, aluminum and titanium. For both dielectrics, it was found that Pt did not react with the films, while Al reacted with them forming an aluminate-like interface and, finally, Ti was effective in scavenging the SiO"2 interface thickness without severely compromising gate dielectric leakage.