Identification of refractory-metal-free C40 TiSi2 for low temperature C54 TiSi2 formation

Abstract

A refractory-metal-free C40 TiSi2 phase formed by pulsed-laser annealing is identified experimentally by combined convergent beam electron diffraction (CBED) study and CBED pattern simulation. The simulation shows that the C40 TiSi2 has a hexagonal structure with the space group P6222 (180) and lattice parameters a=0.471 nm and c=0.653 nm. Upon further furnace annealing or rapid thermal annealing, C54 TiSi2 can be directly achieved from C40 TiSi2 at low temperatures (600–700 °C). This observation suggests that pulsed-laser annealing is promising for extension of TiSi2 into the subquarter micron region in semiconductor device fabrication.

Structural study of refractory-metal-free C40 TiSi2 and its transformation to C54 TiSi2

“…Figure 1͑b͒ ͑bottom spectrum͒ displays the Raman modes of the same as-laser-annealed sample. Compared with the previous results, 10,11 it is obvious that pure C40 TiSi 2 is the dominant phase after the laser annealing process in this work.…”

“…As a new TiSi 2 phase, the crystal structure of C40 TiSi 2 has been systematically investigated by high-resolution transmission electron microscopy ͑HRTEM͒, 11 and the direct phase transformation from the C40 phase to C54 phase was studied by Raman spectroscopy. 10,11 However, the pure C40-C54 transformation bypassing the C49 TiSi 2 phase has never been studied by x-ray diffraction ͑XRD͒, even the XRD pattern of the pure C40 phase resulting from the refractor-metalfree Ti/Si samples. In this work, we used x-ray diffraction to characterize C40 TiSi 2 directly formed by pulsed laser annealing a pure Ti/Si sample and the C40-C54 TiSi 2 phase transformation upon further RTP annealing.…”

“…The preparation of precursor Ti/Si samples and the pulsed laser annealing process has been reported in detail by Chen et al 10 and Li, Chen, and Shen. 11 A Digital Instruments ͑Dimension™ 3000 SPM͒ atomic-force microscope ͑AFM͒ with tapping mode was used to demonstrate the morphology and average grain size of pure C40 TiSi 2 induced by laser annealing. A RTP processor ͑Jipelec JetFirst system͒ was employed to transform pure C40 TiSi 2 to C54 TiSi 2 by heating the samples at different temperatures for 60 s. The samples after various temperature RTP treatments were identified by a SPEX 1702/04 micro-Raman spectrometer with a He-Ne laser ͑ϭ632.8 nm͒ as the excitation source.…”

Mechanism of simultaneous formation of refractory-metal free C40 and C49TiSi2 induced by Q-switched Nd:Yttrium–aluminum–garnet laser irradiation

“…The crystal structure of this refractory-metal free laser induced C40 TiSi 2 was first identified using HRTEM by Chen et al 8 Recently Via et al 21 have also shown that by depositing a thin layer of Ta at the Ti/ Si interface, the C40 TiSi 2 was obtained after annealing at 525°C from their Bragg-Bentano XRD results. Both the refractory-metal free and the refractory-metal doped C40 TiSi 2 obtained by Li et al 9 and Via et al, 21 respectively, have shown that the C40 TiSi 2 has a hexagonal structure with the space group P6 2 22. 8.…”

“…The crystal structure of this C40 TiSi 2 had been studied using high resolution TEM ͑HRTEM͒ by Li et al 9 In this article, we report on the formation of C49 TiSi 2 at two different temperatures ͑i.e., 680 and 1975°C, respectively͒ when blanket Ti/ Si samples were annealed with a a͒ Electronic mail: scip1187@hotmail.com Nd:Yttrium-aluminum-garnet ͑YAG͒ laser with at 0.18 s and with an energy fluence of approximately 1.5 J / cm 2 . Moreover, additional refractory metal ion implantation causes integration issues.…”