Initial stages of growth of heteroepitaxial yttria-stabilized zirconia films on silicon substrates

YSZ is of interest as a heteroepitaxial buffer layer. A low-temperature process was developed to grow high quality heteroepitaxial YSZ films on Si substrates at 200-800 C. The technique involves reactive sputtering in an electron cyclotron resonance plasma stream reactor. Successful growth of this heteroepitaxial film on Si is important for applications such as high temperature superconductors on Si, silicon-on-insulator, and high permittivity dielectrics for dynamic random access memory applications. XRD, RBS and TEM showed that the material prepared was of high crystalline quality. The presence of an oxygen passivating layer on the Si substrate surface was found to be important for the heteroepitaxial growth of this material. Once heteroepitaxial growth is established, it can be successfully continued at substrate temperatures as low as 200 C. Material quality also improved with increasing film thickness due to a self-healing process. Furthermore, material quality could be significantly improved by a postdeposition high temperature anneal step. 19 refs.