Synthesis and thermal stability of Pt3Si, Pt2Si, and PtSi films grown by e-beam co-evaporation

Abstract

a b s t r a c tPlatinum silicide thin films formed via solidesolid reaction of PteSi interfaces play an important role as interconnects in microelectronics. This "self-aligned" silicide formation, however, is diffusion-limited and only Pt 2 Si and PtSi phases form. Also, their usefulness in electronic applications at high temperatures is limited due to agglomeration effects. Here, e-beam co-evaporation is presented as a means of fabricating well-defined films of Pt 3 Si as well as the Pt 2 Si and PtSi phases familiar to conventional, self-aligned silicide technology. PteSi films with a range of compositions (silicon atomic fractions of X Si ¼ 0.00 e0.77) were grown on r-sapphire substrates by co-deposition of independently controlled Pt and Si evaporant fluxes at 400 C. Phase, morphology, and electronic properties were analyzed upon deposition and after vacuum annealing for 48 h at 1000 C. As-deposited films with X Si < 0.70 are polycrystalline and at higher Si concentrations are fully amorphous. Valence spectra from Pt, Pt 2 Si, and PtSi films confirm previous reports and a valence spectrum is presented for the stoichiometric Pt 3 Si phase; these data provide experimental support for recently proposed revisions to the standard transition metalesilicon bonding model. As-deposited films, nominally 200 nm thick, are electrically conductive in the range 0.1 e4.0 Â 10 6 S/m and remain so after vacuum annealing for 48 h at 1000 C. The phase, morphological, and electrical stabilities are attributed to the finely grained as-deposited morphologies of co-evaporated Pt silicide films, which hinder agglomeration at 1000 C for much greater times than do morphologies of traditional, self-aligned silicides grown via solid-state reaction.

Promotion in solid phase reaction of Pt/SiOx bilayer film by electron-orbital-selective-excitation

“…According to the previous literature, 8,9 this peak shi consistent with the movement expected on the basis of the decreased number of Pt-Pt bonds, giving rise to less screening and Coulomb correlation effects in the metal bonds. The number of Pt-Pt bonds is reduced in the Pt/SiO x bilayer lm photo-irradiated at 140 eV than that in the bilayer lm as prepared.…”

Low-temperature formation of platinum silicides on polycrystalline silicon

“…[27], this energy is 71.45 eV, and the same value (71.45 ± 0.2 eV) is given in Ref. [28]. Thus, the component of the Pt 4f line discussed above may be attributed to the Pt 3 Si compound.…”

Investigation of an atomic‐layer‐deposited Al2O3 diffusion barrier between Pt and Si for the use in atomic scale atom probe tomography studies on a combinatorial processing platform

“…Figure 3C It was reported that at least two Pt silicide phases, Pt 2 Si and PtSi, can form at reaction temperatures between 150 C and 500 C, 14 whereby PtSi is the final thermodynamically stable phase. 18,24 Thus, the mixtures observed here consist probably of a PtSi phase (Figure 3) and a Pt 2 Si phase (Figure 4). The different types of mixtures observed here may result from slight differences in the reaction volume or reaction temperatures due to differences in the substrate tips.…”