Highly stable carbon-doped Cu films on barrierless Si

Zhang, X.Y.; Li, X.N.; Nie, Long-Hui; Chu, Jinn P.; Wang, Q.; Lin, C.H.; Chen, Dong

doi:10.1016/j.apsusc.2010.11.095

Cited by 12 publications

(4 citation statements)

References 22 publications

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“…This is not only scientifically interesting, it is important for applications as well. Several technologically relevant silicide systems undergo solid-state amorphization to some degree, including the Ni-Si, Ti-Si [60] (contact material for transistors), Cu-Si [61] (barrierless interconnects) and Li-Si [62] (energy storage) systems. By selecting the optimal impurity and its concentration, one might find ways of enhancing these SSA reactions, leading to new reaction paths and/or new thin film applications.…”

Section: Discussionmentioning

confidence: 99%

Impurity-enhanced solid-state amorphization: the Ni–Si thin film reaction altered by nitrogen

Stiphout

Geenen

Santos

et al. 2019

J. Phys. D: Appl. Phys.

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Solid-state amorphization, the growth of an amorphous phase during annealing, has been studied in a wide variety of thin film structures. Whereas research on the remarkable growth of such a metastable phase has mostly focused on strictly binary systems, far less is known about the influence of impurities on such reactions. In this paper, the influence of nitrogen, introduced via ion implantation, is studied on the solid-state amorphization reaction of thin (35 nm) Ni films with Si, using in situ XRD, ex situ RBS, XTEM, and synchrotron XRD. It is shown that due to small amounts of nitrogen (< 2 at.%), an amorphous Ni-Si phase grows almost an order of magnitude thicker during annealing than for unimplanted samples. Nitrogen hinders the nucleation of the first crystalline phases, leading to a new reaction path: the formation of the metal-rich crystalline silicides is suppressed in favour of an amorphous Ni-Si alloy; during a brief temperature window between 330 and 350 • C, the entire film is converted to an amorphous phase. The first crystalline structure to grow is the orthorhombic NiSi phase. We demonstrate that this phenomenon occurs only under specific implantation conditions. In particular, the initial distribution of nitrogen upon implantation is crucial: sufficient nitrogen impurities must be present at the interface throughout the reaction. Introducing implantation damage without nitrogen impurities (e.g. by implanting a noble gas) does not cause the enhanced solid-state reaction. Moreover, we show that the stabilizing effect of nitrogen on amorphous Ni-Si films (with a composition ranging from 40% to 50% Si) is not restricted to thin film reactions, but is a general feature of the Ni-Si system.

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Section: Discussionmentioning

confidence: 99%

Impurity-enhanced solid-state amorphization: the Ni–Si thin film reaction altered by nitrogen

Stiphout

Geenen

Santos

et al. 2019

J. Phys. D: Appl. Phys.

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“…According to Cu-Sn binary phase diagram and literature [15], Sn would have a trace of solid solubility in Cu, which would make the resistivity increase. While Cu-C binary phase diagram and previous works [13,16,17] showed that C had no solid solubility in Cu, so C could only exist at the defects, grain boundaries, etc. In the Cu films, C elements had less effect on the resistivity.…”

Section: Resultsmentioning

confidence: 89%

Stability and Microstructure Characterization of Barrierless Cu (Sn, C) Films

Jin

et al. 2014

AMR

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Thermal stability, adhesion and electronic resistivity of the Cu alloy films with diffusion barrier elements (large atom Sn and small atom C) have been studied. Ternary Cu (0.6 at.% Sn, 2 at.% C) films were prepared by magnetron co-sputtering in this work. The microstructure and resistivity analysis on the films showed that the Cu (0.6 at.% Sn, 2 at.% C) film had better adhesion with the substrate and lower resistivity (2.8 μΩ·cm, after annealing at 600 °C for 1 h). Therefore, the doping of carbon atoms makes less effect to the resistivity by decreasing the amount of the doped large atoms, which results in the decreasing of the whole resistivity of the barrierless structure. After annealing, the doped elements in the film diffused to the interface to form self-passivated amorphous layer, which could further hinder the diffusion between Cu and Si. So thus ternary Cu (0.6 at.% Sn, 2 at.% C) film had better diffusion barrier effect. Co-doping of large atoms and small atoms in the Cu film is a promising way to improve the barrierless structure.

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“…Due to the difficulty in achieving uniform depositions of ultra-thin barrier layers, more attention has been paid to self-formed diffusion barriers (barrierless metallization) in recent years [13][14][15]. The self-formed barrier layer offers low electrical resistivity, resistance to Cu diffusion, resistance to electromigration and compatibility with conformal deposition techniques [16][17][18][19][20][21]. A self-formed barrier scheme is achieved by doping with diffusion barrier elements as well as their nitrides and carbides, such as Ti, Zr, Mn and WN [22][23][24][25][26][27][28].…”

Section: Introductionmentioning

confidence: 99%

Self-Formed Diffusion Layer in Cu(Re) Alloy Film for Barrierless Copper Metallization

et al. 2022

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The barrier properties and diffusion behavior of Cu(Re) alloy films were studied. The films were deposited onto barrierless SiO2/Si by magnetron sputtering. X-ray diffraction patterns and electric resistivity results proved that the Cu(Re) alloy films without a barrier layer were thermally stable up to 550 °C. Transmission electron microscopy images and energy-dispersive spectrometry employing scanning transmission electron microscopy provided evidence for a self-formed Re-enriched diffusion layer between the Cu(Re) alloy and SiO2/Si substrate. Furthermore, the chemical states of Re atoms at the Cu(Re)/SiO2 interface were analyzed by X-ray photoemission spectroscopy. The self-formed diffusion layer was found to be composed of Re metal, ReO and ReO3. At 650 °C, the Cu(Re) layer was completely destroyed due to atom diffusion. The low electrical resistivity in combination with the high thermal stability suggests that the Cu(Re) alloy could be the ultimate Cu interconnect diffusion barrier.

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Highly stable carbon-doped Cu films on barrierless Si

Cited by 12 publications

References 22 publications

Impurity-enhanced solid-state amorphization: the Ni–Si thin film reaction altered by nitrogen

Impurity-enhanced solid-state amorphization: the Ni–Si thin film reaction altered by nitrogen

Stability and Microstructure Characterization of Barrierless Cu (Sn, C) Films

Self-Formed Diffusion Layer in Cu(Re) Alloy Film for Barrierless Copper Metallization

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