Growth of highly oriented HfO_2 thin films of monoclinic phase on yttrium-stabilized ZrO_2 and Si substrates by pulsed-laser deposition

摘要

We report on the growth of highly oriented HfO_2 thin films of monoclinic phase stabilized by 5% Co doping on (001) yttrium-stabilized zirconia (YSZ) using pulsed-laser deposition at 700℃ at an oxygen partial pressure of 10~(-4) Torr. On the other hand, pure HfO_2 of such quality did not grow on YSZ in wide range of growth parameters. Rutherford backscattering-ion channeling in this film showed a 24% minimum yield (χ_(min)) indicating highly oriented film growth, while hardly any ion channeling was observed in the undoped sample. High-resolution transmission electron microscopy revealed a sharp interface, and no signature of Co clusters. Electron energy loss spectroscopy showed that Co is in the 2+ state. Attempts were also made to grow films on a (001) Si substrate, and the results showed a very low ion channeling yield (～8%).