Paper TF-TuP1
Spatially Varied Orientation Selective Epitaxial Growth of CeO₂(100) and (110) Areas on Si(100) Substrates by Reactive Magnetron Sputtering Utilizing Electron Beam Irradiation

Tuesday, November 1, 2011, 6:00 pm, Room East Exhibit Hall

Cerium dioxide is of great interest due to favorable properties as an electronic material, such as high dielectric constant of 26, high chemical stability, transmission in visible and infrared regions, and high efficient ultra-violet absorption. Epitaxial growth of CeO₂ layers on Si substrates has been studied making the best use of a close lattice parameter matching relation. Recently, we have found that orientation selective epitaxial (OSE) growth of (100) and (110) oriented CeO₂ layers on Si(100) is capable by controlling surface potential distribution in reactive magnetron sputtering. Non-polar CeO₂(110) grows on Si(100) with usual non-modified surface potential, whereas polar CeO₂(100) grows on Si(100) with adequately bent surface potential. We are studying two OSE control methods, one is substrate bias application[1] and the other is low energy electron beam irradiation.[2,3] The latter has the attractive possibility of spatially varied two dimensional control of OSE grown regions.[4] This paper describes experimental results of electron beam induced OSE growth with patterned scanning of 90 eV electron beams. The size and position of the electron beam irradiation area were controlled using absorbed electron current image observation. RHEED and XRD analyses proved the realization of two dimensionally controlled OSE growth of CeO₂(100) and (110) areas in electron beam irradiated and non-irradiated areas, respectively. Precise XRD peak profile measurements revealed that there are considerably wide transition regions in between the above two areas, which contain both orientation components. For the application to two dimensionally patterned hybrid orientation technology, the transition region width should be reduced significantly. Our experiments clarified that the width of the transition region reduces proportionally with the logarithm of underlying Si substrate resistivity, reflecting the surface spread of potential distribution. These results will lead to sophisticated microelectronics devices using hybrid orientation technology. This work was supported by KAKENHI (20560024). A part of this work were conducted at the AIST Nano-Processing Facility, supported by "Nanotechnology Network Japan" of the MEXT, Japan.

[1] T. Inoue, N. Sakamoto, M. Ohashi, S. Shida and A. Horikawa, J. Vac. Sci. Technol., A22, 46 (2004).

[2] T. Inoue, T. Saito and S. Shida, J. Cryst. Growth, 304, 1 (2007).

[3] T. Inoue, H. Ohtake, J. Otani and S. Shida, J. Electrochem. Soc., 155, G237 (2008).

[4] T. Inoue, N. Igarashi, Y. Kanno and S. Shida, Thin Solid Films, to be published.