Growth of epitaxial C54 TiSi2 on Si(111) substrate by in situ annealing in ultrahigh vacuum

Abstract

The growth of Ti and the formation of epitaxial Ti silicide on Si(111)-7×7 were investigated by using reflection high-energy electron diffraction (RHEED) and high-resolution transmission electron microscopy (HRTEM). The growth mode of Ti is Stransky–Krastanov type when the substrate temperature is room temperature (RT). On the other hand, it is Volmer–Weber type when the substrate temperature is ∼550 °C. The HRTEM lattice image and transmission electron diffraction pattern show that C54 TiSi2 is grown epitaxially on a Si substrate when 160 ML of Ti is deposited on a Si(111)-7×7 surface at RT followed by in situ annealing at 750 °C for 10 min in ultrahigh vacuum (UHV). The TiSi2/Si interface is somewhat incoherent, but the developed TiSi2 crystallites are single crystal with matching face relationships of TiSi2(111)∥Si(111), TiSi2(311)∥Si(111), and TiSi2(022)∥Si(111). A thin single-crystal Si overlayer with [111] direction is grown on the TiSi2 surface when TiSi2/Si(111) is annealed at ∼900 °C in UHV, which is confirmed by observing the Si(111)-7×7 RHEED pattern.

Characterization of C54 titanium silicide thin films by spectroscopy, microscopy and diffraction

“…While substantial characterization and application results for titanium silicide have been previously reported (e.g. [1,2,[4][5][6][7]), this paper aims to comprehensively analyze titanium silicide by a variety of spectroscopy, diffraction and microscopy techniques. This paper reports on results obtained from these techniques, and many of these results add further to those previously published (such as those in [4][5][6][7]).…”

“…[1,2,[4][5][6][7]), this paper aims to comprehensively analyze titanium silicide by a variety of spectroscopy, diffraction and microscopy techniques. This paper reports on results obtained from these techniques, and many of these results add further to those previously published (such as those in [4][5][6][7]). These improvements include Auger electron spectroscopy (AES) depth profiles showing a better 1 : 2 ratio for titanium to silicon, and AES and secondary ion mass spectroscopy (SIMS) depth profiles showing a very uniform composition throughout the thin film.…”

“…Diffraction techniques were used to study the orientation of the thin films formed. TiSi 2 exists in two phases: basecentred orthorhombic C49 and face-centred orthorhombic C54 [1,6]. C54 is the desired low resistivity (14-17 µ cm) phase for CMOS and bulk micro-machining applications.…”