Deriving the kinetic parameters for Pt-silicide formation from temperature ramped in situ ellipsometric measurements

Stark, T.; Grünleitner, H.; Hundhausen, Martin; Ley, L.

doi:10.1016/s0040-6090(99)00699-9

Cited by 28 publications

(16 citation statements)

References 20 publications

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“…Much of the recent work on Pt 2 Si and PtSi has focused on the kinetics and stoichiometry under ultrahigh vacuum ͑UHV͒ annealing conditions. [10][11][12][13] In this article, we propose a detailed study of the Pt silicidation mechanisms using various annealing conditions like UHV and rapid thermal annealing with a particular attention on the interface reaction at room temperature, on the influence of oxygen during silicidation reaction and on the optimum conditions to obtain the lowest specific contact resistance. After a description of the preparation techniques and measurement procedures in Sec.…”

Section: Introductionmentioning

confidence: 99%

Formation of platinum-based silicide contacts: Kinetics, stoichiometry, and current drive capabilities

Larrieu

Dubois

Wallart

et al. 2003

Journal of Applied Physics

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A detailed analysis of the formation of Pt 2 Si and PtSi silicides is proposed, based on x-ray photoelectron spectroscopy ͑XPS͒, transmission electron microscopy ͑TEM͒, and electrical characterizations. Published kinetics of the Pt 2 Si and PtSi transformations under ultrahigh vacuum condition are consolidated on the basis of XPS measurements performed during an in situ annealing at a constant heating rate. At room temperature, an incomplete Pt x Si reaction is clearly identified by XPS depth profiling. Using rapid thermal annealing at 300, 400, and 500 °C, the sequential Pt-Pt 2 Si-PtSi reaction chain is found to be completed within 2 min. Outdiffusion of silicon to the top surface is shown to be responsible for the formation of a thin SiO 2 capping layer at 500 °C. Pileup of oxygen occurring at the Pt 2 Si/Pt reaction front is clearly identified as an inhibiting factor of the silicidation mechanism. Another incomplete reaction scheme limited to the unique formation of Pt 2 Si is exemplified in the case of ultra thin silicon-on-insulator films. Finally, current drive measurements on PtSi Schottky contacts have allowed us to identify 300 °C as the optimum annealing temperature while TEM cross sections demonstrate the formation of a smooth and continuous PtSi/Si interface at 300 °C.

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Section: Introductionmentioning

confidence: 99%

Formation of platinum-based silicide contacts: Kinetics, stoichiometry, and current drive capabilities

Larrieu

Dubois

Wallart

et al. 2003

Journal of Applied Physics

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“…[16] In an early comprehensive study of tribopolymer formation, Pt x Si formed from thin film Pt and a sc-Si wafer is described by a two-reaction process (Figure 1c). [23,24] Since common NEM switch geometries [2,25] demand silicidation away from the sc-Si carrier wafer, the sc-Si/Pt silicidation process is incompatible with NEM switch geometries, especially if co-integration with CMOS is desired. Furthermore, silicide-release using existing device topologies would require silicidation on both the top and bottom of features, which is not compatible with sc-Si/Pt process.…”

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confidence: 99%

Tunable, Source‐Controlled Formation of Platinum Silicides and Nanogaps from Thin Precursor Films

Streller

Wabiszewski

Mangolini

et al. 2014

Adv Materials Inter

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Keywords: platinum silicide, thin films, X-ray photoelectron spectroscopy, nanoindentation, conductive atomic force microscopy Controlling the stoichiometry and properties of thin films formed from solid-state reactions is relatively unexplored, yet important for a broad range applications including many throughout the semiconductor industry. [1,2] Here we use source-limited solid-state diffusion to tune the stoichiometry and properties of thin films of platinum silicide (Pt x Si), a material with multiple attractive properties for electro-mechanical applications. [3,4] We demonstrate for the first time the formation of Pt x Si from thin sequentially-deposited layers of platinum (Pt) and amorphous silicon (a-Si), and show that the resulting stoichiometry can be tuned over a wide range by simply changing the thickness ratio of the precursor films. Pt-rich silicide films are especially attractive as a contact material for nanoelectromechanical (NEM) contact switches, due to the combination of high hardness and elastic modulus, surface stability, and metal-like electrical conductivity. This method of tuning the stoichiometry and properties of thin films is applicable to any metal silicide. 2Metal silicides possess a rare combination of thermal stability, mechanical robustness, and metal-like electrical conductivity. This renders them popular in both bulk and thin film form for many structural and electronic applications, such as materials for jet engines, thermoelectric devices, Ohmic and rectifying contacts to silicon, local interconnects, and diffusion barriers. [5] A more recent application involves their use in NEM contact switches.NEM switches are a potential next-generation, low power alternative to fully-electronic complementary metal-oxide semiconductor (CMOS) transistors (Figure 1a) that may significantly decrease microprocessor power consumption. [1,2,6] These devices promise orders of magnitude lower power consumption and superior ON/OFF ratios than CMOS (Figure 1b) Ð a consequence of NEM device topology and the presence of a physical gap between the source and drain terminals. [1,2] NEM switches have also demonstrated applications not accessible with CMOS Ð most notably exposure to high temperature, [7] radiation, [8,9] and external electric fields.[10] These advantages also render them of interest for future memory technologies.[1] However, the reliability of the contact interface is a concern due to tribological issues, and remains a key challenge for their commercialization. a, Schematic of a typical solid-state switch and an electrostatically actuated mechanical switch that highlights the structural analogies between both switch types. The magnified view to the right illustrates the physical separation between source and drain in the mechanical switch in its OFF state and emphasizes the demanding requirements on contact materials in nanoscale mechanical switches, which are a consequence of the harsh operating conditions (high contact stresses and current densities). b, Schematic current-voltage p...

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“…The well-studied Pt/sc-Si system is characterized by the specific Pt x Si formation sequence of Pt diffusing into sc-Si around 250–300 °C to form the intermediate Pt 2 Si phase. After all Pt is consumed, sc-Si will diffuse into Pt 2 Si at 300–450 °C to form the thermodynamically stable PtSi phase. , We hypothesize that the amorphous nature of the a-Si film used in our experiments alters the diffusion behavior compared to that of sc-Si, which leads to the formation of the Pt 3 Si phase. The Pt 3 Si phase is formed due to the fact that in the Pt/a-Si system, a-Si acts initially as the dominant diffusing species (DDS) in contrast to the Pt/sc-Si system, where Pt is initially the DDS.…”

Section: Results and Discussionmentioning

confidence: 94%

Novel Metal Silicide Thin Films by Design via Controlled Solid-State Diffusion

et al. 2015

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: In the quest to accelerate the discovery and deployment of new materials with ideal and tailored properties, synthesis via solid-state diffusion holds particular promise as it allows the crystal structure and stoichiometry of thin films to be controlled independently of the deposition method. However, the kinetics and the quality of the resulting materials remain relatively unexplored. Here we demonstrate both source-limited and kinetically-limited solid-state diffusion as novel routes to tune the stoichiometry of platinum silicide (Pt x Si) thin films, representative of metal silicides which have attractive mechanical and electronic properties. Using in situ heating inside a transmission electron microscope (TEM) while performing electron diffraction, we show that both routes lead to stoichiometrically-controlled formation of Pt x Si (x = 1, 2, 3) thin films with high phase selectivity, revealing the crystal structure and formation sequence for each phase. The Pt x Si formation process from sequentially-deposited layers of platinum (Pt) and amorphous silicon (a-Si) significantly differs from the Pt/single-crystal silicon (sc-Si) case, allowing the formation of Pt 3 Si thin films for the first time.

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Deriving the kinetic parameters for Pt-silicide formation from temperature ramped in situ ellipsometric measurements

Cited by 28 publications

References 20 publications

Formation of platinum-based silicide contacts: Kinetics, stoichiometry, and current drive capabilities

Formation of platinum-based silicide contacts: Kinetics, stoichiometry, and current drive capabilities

Tunable, Source‐Controlled Formation of Platinum Silicides and Nanogaps from Thin Precursor Films

Novel Metal Silicide Thin Films by Design via Controlled Solid-State Diffusion

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