Low resistivity tungsten for 32nm node MOL contacts and beyond

Papadatos, Filippos; Wong, Keith H.K.; Arunachalam, V.; Shin, Chung Hwan; Li, Zhengwen; Chudzik, M.; Lee, Woo-Hyeong; Xing, Aimin

doi:10.1016/j.mee.2011.04.044

Cited by 13 publications

(7 citation statements)

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“…Low and uniform barrier heights are desired to reduce the parasitic contact resistance, which has been achieved via exotic silicides and monolayer-thick dielectric layers. [1][2][3][4][5][6] In the traditional Schottky-Mott model, the barrier height is determined by the work function of the metal and electron affinity of the semiconductor and results from charge transfer from the semiconductor to the metal. [7][8][9][10] At the nanometer size scale, the uniformity of the electrostatic barrier is critical; the absence or presence of a single ionized impurity near the interface, monolayer fluctuations in the dielectric layer, or slight stoichiometry variations in the silicide can significantly alter the electrostatics and resulting performance.…”

Section: Detection Of Silicide Formation In Nanoscale Visualization Omentioning

confidence: 99%

Detection of silicide formation in nanoscale visualization of interface electrostatics

Nolting

Durcan

LaBella

2017

Applied Physics Letters

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The ability to detect localized silicide formation at a buried metal semiconductor Schottky interface is demonstrated via nanoscale measurements of the electrostatic barrier. This is accomplished by mapping the Schottky barrier height of the Cr/Si(001) interface by ballistic electron emission microscopy (BEEM). Monte-Carlo modeling is employed to simulate the distributions of barrier heights that include scattering of the electrons that traverse the metal layer and a distribution of electrostatic barriers at the interface. The best agreement between the model and the data is achieved when specifying two barrier heights less than 60 meV from one another instead of a singular barrier. This provides strong evidence that localized silicide formation occurs that would be difficult to observe in averaged BEEM spectra or conventional current voltage measurements.

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Section: Detection Of Silicide Formation In Nanoscale Visualization Omentioning

confidence: 99%

Detection of silicide formation in nanoscale visualization of interface electrostatics

Nolting

Durcan

LaBella

2017

Applied Physics Letters

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“…1,2 Schottky diodes have a low capacitance and recovery time and are also being studied as they are found in source drain contacts in silicon based MOSFETs. [3][4][5][6][7] For an n-type semiconductor to metal interface, the potential barrier formed is the energy difference between the Fermi level of the metal and the bottom of the conduction band in the semiconductor. For a p-type semiconductor to metal interface, the potential barrier formed is the energy difference between the Fermi level of the metal and the top of the valance band in the semiconductor.…”

Section: Introductionmentioning

confidence: 99%

Nanoscale mapping of the W/Si(001) Schottky barrier

Durcan

Balsano

LaBella

2014

Journal of Applied Physics

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The W/Si(001) Schottky barrier was spatially mapped with nanoscale resolution using ballistic electron emission microscopy (BEEM) and ballistic hole emission microscopy (BHEM) using n-type and p-type silicon substrates. The formation of an interfacial tungsten silicide is observed utilizing transmission electron microscopy and Rutherford backscattering spectrometry. The BEEM and BHEM spectra are fit utilizing a linearization method based on the power law BEEM model using the Prietsch Ludeke fitting exponent. The aggregate of the Schottky barrier heights from n-type (0.71 eV) and p-type (0.47 eV) silicon agrees with the silicon band gap at 80 K. Spatially resolved maps of the Schottky barrier are generated from grids of 7225 spectra taken over a 1 lm Â 1 lm area and provide insight into its homogeneity. Histograms of the barrier heights have a Gaussian component consistent with an interface dipole model and show deviations that are localized in the spatial maps and are attributed to compositional fluctuations, nanoscale defects, and foreign materials. V C 2014 AIP Publishing LLC. [http://dx

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“…Tungsten (W) is one of the metals commonly adopted by industry in integrated circuits to realize electrodes and interconnects [3]. With decreasing the film thickness, the main challenge is to keep the sheet and contact resistances low enough, in line with the application demands [4]. Further, the ultra-thin metal films may be expected to exhibit a field effect, which is not observable in the thick layers due to the high electron density and the related screening effect [5][6][7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Conduction and Electric Field Effect in Ultra-Thin Tungsten Films

Zouw¹,

Aarnink²,

Schmitz³

et al. 2020

IEEE Trans. Semicond. Manufact.

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Ultra-thin tungsten films were prepared using hotwire assisted atomic layer deposition. The film thickness ranged from 2.5 to 10 nm, as determined by spectroscopic ellipsometry and verified by scanning electron microscopy. The films were implemented in conventional Van der Pauw and circular transmission line method (CTLM) test structures, to explore the effect of film thickness on the sheet and contact resistance, temperature coefficient of resistance (TCR), and external electric field applied. All films exhibited linear current-voltage characteristics. The sheet resistance was shown to considerably vary across the wafer, due to the film thickness non-uniformity. The TCR values changed from positive to negative with decreasing the film thickness. A field-induced modulation of the sheet resistance up to ∼4.6·10 −4 V −1 was obtained for a 2.5 nm thick film, larger than that generally observed for metals.

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Low resistivity tungsten for 32nm node MOL contacts and beyond

Cited by 13 publications

References 0 publications

Detection of silicide formation in nanoscale visualization of interface electrostatics

Detection of silicide formation in nanoscale visualization of interface electrostatics

Nanoscale mapping of the W/Si(001) Schottky barrier

Conduction and Electric Field Effect in Ultra-Thin Tungsten Films

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