The effect of oxygen in Ru gate electrode on effective work function of Ru/HfO2 stack structure

Nabatame, Toshihide; Segawa, Kouji; Kadoshima, Masaru; Takaba, Hiromitsu; Iwamoto, Kunihiko; Kimura, Shota; Y.Nunoshige, Y.Nunoshige; Satake, Hideki; Ohishi, T.; Toriumi, Akira

doi:10.1016/j.mssp.2006.10.013

Cited by 17 publications

(9 citation statements)

References 4 publications

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“…The latter value (cut off energy) was estimated to be 16.8 eV and it results in work functions of 4.4 eV. According to literature data [7,10], the work function of ruthenium ranges between 4.5 and 5.9 eV depending on the crystallographic direction, thus the obtained value is appropriate.…”

Section: Resultsmentioning

confidence: 97%

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Ru/GaN(0001) Interface Properties

et al. 2017

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We report the results of our studies of ruthenium layer structures adsorbed on GaN(0001). Ruthenium was evaporated at room temperature under ultrahigh vacuum conditions onto n-type GaN substrates epitaxially grown on sapphire. When X-ray photoelectron spectroscopy confirmed the presence of Ru bonds in the deposited adlayer, the ultraviolet photoelectron spectroscopy shown a peak at the Fermi level as well as lines originating from ruthenium. The height of the Schottky barrier was calculated based on the data measured by X-ray photoelectron spectroscopy and ultraviolet photoelectron spectroscopy and amounts to 1.5 eV. The work function of Ru adlayer is 4.4 eV, while the electron affinity of n-GaN(0001) substrate equals 3.4 eV.

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Section: Resultsmentioning

confidence: 97%

“…Electrical properties of ruthenium based contacts to n-GaN were investigated by measurement of I−V curves and the metal was found to be a good candidate for the high temperature applications [4][5][6][7]. Despite the above, there has still been a deficit of basic research on pure Ru layers on GaN substrates reported thus far.…”

Section: Introductionmentioning

confidence: 99%

Ru/GaN(0001) Interface Properties

et al. 2017

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“…Since RuO 2 has a higher work function (5.2 eV) than pure Ru (4.8 eV), 7,8 oxygen impurities in the films increased the EWF of the films. 71,72 It should be noted that the resistivities of the EA-ALD films were lower than that of control Ru despite the higher oxygen impurity concentration.…”

Section: Resultsmentioning

confidence: 98%

Advanced atomic layer deposition (ALD): controlling the reaction kinetics and nucleation of metal thin films using electric-potential-assisted ALD

et al. 2023

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“…The calculated EWFs of the DF-ALD films (D4) (4.79 eV) were larger than that of the control ALD film (4.56 eV), reaching that of bulk Ru (4.8 eV). This is attributed to the higher physical density and oxygen concentration of the DF-ALD film, as discussed above. − …”

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confidence: 90%

Advanced Atomic Layer Deposition: Ultrathin and Continuous Metal Thin Film Growth and Work Function Control Using the Discrete Feeding Method

2022

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The ultrathin and continuous ruthenium (Ru) film was deposited through an improved atomic layer deposition (ALD) process with a discrete feeding method (DFM), called DF-ALD, employing a cut-in purge step during the precursor feeding. The excess precursor molecules can be physically adsorbed onto the chemisorbed precursors on the substrate during precursor feeding, which screens the reactive sites on the surface. Using DF-ALD, surface coverage of precursors was enhanced because the cut-in purge removes the physisorbed precursors securing the reactive sites beneath them; thus, nucleation density was greatly increased. Therefore, the grain size decreased, which changed the microstructure and increased oxygen impurity concentration. However, a more metallic Ru thin film was formed due to thermodynamic stability and improved physical density. Consequently, DF-ALD enables the deposition of the ultrathin (3 nm) and continuous Ru film with a low resistivity of ∼60 μΩ cm and a high effective work function of ∼4.8 eV.

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The effect of oxygen in Ru gate electrode on effective work function of Ru/HfO2 stack structure

Cited by 17 publications

References 4 publications

Ru/GaN(0001) Interface Properties

Ru/GaN(0001) Interface Properties

Advanced atomic layer deposition (ALD): controlling the reaction kinetics and nucleation of metal thin films using electric-potential-assisted ALD

Advanced Atomic Layer Deposition: Ultrathin and Continuous Metal Thin Film Growth and Work Function Control Using the Discrete Feeding Method

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