Application of sputter etching treatment to the formation of semiconducting silicide film on Si substrate

Yamaguchi, Kenji; Esaka, Fumitaka  ; Sasase, Masato*; Yamamoto, Hiroyuki; Hojo, Kiichi

"Semiconducting silicides", such as -FeSi, BaSi, MgSi, etc. are composed of elements which are non or less toxic and are naturally abundant, so that they are considered to be ecologically friendly. These materials are being investigated for applications in optoelectronics, photovoltaics, photonics, thermoelectrics, and so on. In order to fabricate silicide films on crystalline Si substrate, sputter-etching (SE) of the substrate with low energy ion beams has been successfully applied. When the conditions are met, a highly-oriented -FeSi (100) film can be grown on Si (100) substrate by means of ion beam sputter deposition method. According to cross-sectional transmission electron microscopy (TEM) observation, the interface of the SE-treated substrate and the film deposited at 973 K is smooth, although some defects are produced as a result of this treatment. On the other hand, a combination of X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS) revealed that relatively homogeneous -FeSi surface is formed at this temperature. In order to further improve the film properties with smaller amount of defects, SE-treatment is performed with the ions whose incident energy is below 1 keV. X-ray diffraction (XRD) analysis confirmed that highly-oriented -FeSi (100) film can be also obtained with SE-treatment by 0.8 keV Ne ions, as in the case of 3.0 keV Ne.