Growth of Ti and TiSi2 films on Si(111) by low energy Ti+ beam deposition

The deposition of titanium and titanium disilicide thin films on Si(lll) by low-energy (10-500 eV) Ti+ beams in the temperature range 25-700 degrees C has been investigated by in-situ Auger electron spectroscopy (AES) and ref lection high-energy electron diffraction (RHEED) as well as ex-situ depth p rofile X-ray photoelectron spectroscopy(XPS), atomic force microscopy (AFM) , and transmission electron diffraction (TED). Small XPS chemical shifts in the Si-2p, and Ti-2p peaks and changes in the AES line shapes originating from elemental silicon and titanium and the titanium disilicide compound ha ve been resolved. The XPS shifts were used for resolution of the silicide l ayer in the depth profiles. This interfacial silicide layer is formed even at 25 degrees C, and its characteristics are dependent on both Ti+ energy a nd Si temperature. The RHEED and TED results confirm the growth of a polycr ystalline Ti film for T less than or equal to 500 degrees C, the C49-TiSi2 phase for T similar to 600 degrees C, the C54-TiSi2, phase for T similar to 700 degrees C or above, and the existence of synergistic effects between t he substrate temperature and Ti+ kinetic energy on the crystalline quality of the films. The AFM images exhibit a broad range of morphologies as a fun ction of growth conditions. The effects of energetic ions and temperature i n Ti and TiSi2 film deposition are discussed accordingly. (C) 2000 Elsevier Science B.V. All rights reserved.