Flatband voltage shift of ruthenium gated stacks and its link with the formation of a thin ruthenium oxide layer at the ruthenium/dielectric interface

Li, Z.; Schram, T.; Pantisano, L.; Conard, Thierry; Elshocht, Sven Van; Deweerd, W.; Gendt, Stefan De; Meyer, K. De; Stesmans, André; Shamuilia, Sheron; Afanas’ev, V. V.; Akheyar, A.; Brunco, D.P.; Yamada, Naoki; Lehnen, P.

doi:10.1063/1.2429730

Cited by 22 publications

(14 citation statements)

References 39 publications

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“…223,224 However, for polycrystalline Ru, no 3D oxide growth has been observed, 265,266 with only increased roughening being detected. 267 In this thesis, we want to have a tool that allows us to recognize such (possible) 3D features growing in our relevant polycrystalline Ru films during thermal oxidation.…”

Section: Motivation For Its Usementioning

confidence: 99%

“…265,266,267 Although, an increased roughening has been detected at enhanced temperatures in these studies, 267 it has not been recognized as 3D growth, and only thin film RuOx growth has been reported. 265,266 In this thesis (Chapter 3), we report on the simultaneous 2D (thin film) and 3D (nano-column) growth of ruthenium oxide, experimentally observed for thermally oxidized polycrystalline Ru thin films. In addition, it is also found that the thin film oxide does not grow as a single layer but a combination of two layers on top of each other, a low density RuOx (2<x≤3) layer on top of a near bulk density RuO2 layer.…”

mentioning

confidence: 98%

“…266,267 However, in all these studies which monitor the oxide growth, there is no either experimental or simulated data in diffusion kinetics (diffusion constants and activation energies) for oxygen diffusion in RuO2 thin films that would allow to understand how oxygen penetrates a RuO2 protective film towards underneath layers during thermal oxidation. Thus, in this thesis (Chapter 4), the diffusion rates and activation energies for oxygen diffusion through a few nanometer thick ruthenium oxide layer have been accurately determined.…”

Section: Current Status Of Oxygen Diffusion Through Ruo2 and Zro2 Filmsmentioning

confidence: 99%

“…223,224 Contrarily, for polycrystalline Ru, no 3D islands have been detected, with only thin film oxide growth being observed. 265,266 Combining XRR, AES, AR-XPS, AFM, XRD and HR-TEM, a Introduction concurrent 2D and 3D ruthenium oxide growth model has been proposed in Chapter 3 for thermal oxidation of polycrystalline Ru thin films. In addition, in situ XRR has also allowed us to detect that the thin film (2D) ruthenium oxide does not grow as a single layer but a combination of two layers on top of each other, a low density RuOx (2<x≤3) layer on top of a near bulk density RuO2 layer, as also presented in Chapter 3.…”

Section: Outline Of This Thesismentioning

confidence: 99%

“…223,224 For polycrystalline Ru no 3D clusters have been seen, with only thin film oxide growth being observed. 265,266,267 In this chapter, we report on the simultaneous 2D (thin film) and 3D (nano-column) growth of ruthenium oxide experimentally observed for thermally oxidized polycrystalline Ru thin films. Furthermore, it is also found that the thin film oxide does not grow as a single layer but a combination of two layers on top of each other.…”

Section: Introductionmentioning

confidence: 99%

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Growth and thermal oxidation of Ru and ZrO2 thin films as oxidation protective layers

Ribera¹

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Section: Motivation For Its Usementioning

confidence: 99%

mentioning

confidence: 98%

Section: Current Status Of Oxygen Diffusion Through Ruo2 and Zro2 Filmsmentioning

confidence: 99%

Section: Outline Of This Thesismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Growth and thermal oxidation of Ru and ZrO2 thin films as oxidation protective layers

Ribera¹

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Electron energy distribution in Si/TiN and Si/Ru hybrid floating gates with hafnium oxide based insulators for charge trapping memory devices

Cerbu

Andreev

Lisoni

et al. 2016

Physica Status Solidi (a)

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Scaling the planar NAND flash cells to the 20 nm node and beyond mandates introduction of inter‐gate insulators with high dielectric constant (κ). However, because these insulators provide a smaller electron barrier at the interface with the poly‐Si floating gate, the program window and the retention properties of these scaled cells are jeopardized. To reduce the charge loss from the floating to the control gate, one may consider the introduction of a hybrid floating gate (HFG) structure comprised of poly‐Si and a high work function (WF) metal, e.g., TiNx (x ∼ 1; WF ∼ 4.7 eV) or Ru (WF ∼ 5.3 eV). However, the very HFG concept is based on the assumption that electron trapping occurs inside the HFG stack rather than on traps present in the high‐κ insulator. To examine this critical hypothesis, we analyzed the energy distribution of electrons trapped in flash cells with poly‐Si(2 nm)/TiN (6 nm)/Hf0.8Al0.2Ox(19 nm, κ ∼ 15–19)/TiNx (10 nm) and Si(2 nm)/Ru (1 nm)/Hf0.8Al0.2Ox(5 nm)/Al2O3 (5 nm)/Hf0.8Al0.2Ox (5 nm)/TiNx (10 nm) trapping gate stacks using the exhaustive photo‐depopulation spectroscopy. We found that trapped electron energy levels show a broad distribution (± 0.3 eV) centred at ∼3.2 eV below the oxide conduction band. The energy onset of electron de‐trapping at ∼2.8 eV matches the TiNx/HfO2 barrier height found from internal photoemission experiments, indicating that electrons are predominantly trapped inside the HFG.

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Internal Photoemission Metrology of Inhomogeneous Interface Barriers

Afanas’ev

Kolomiiets

Houssa

et al. 2017

Physica Status Solidi (a)

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Interfaces of heterogeneous solids, ranging from polycrystalline materials to composites, are frequently encountered in nanotechnology. Electron transport in these materials and across their interfaces critically depends on the energy barriers electrons encounter on their way. Because of electrode structural heterogeneity, the barriers may exhibit significant spatial variations resulting in a broad distribution of barrier heights and built-in potentials. Quantification of the distributed interface barriers represents a formidable experimental challenge since direct association of interface properties with those of an outer free surface is generally inaccurate. Here we present a methodology enabling quantification of electron barriers at interfaces of semiconductors and metals with insulators using the electric field-dependent internal photoemission (IPE) of electrons. It is shown that practically relevant interfaces may contain "patches" with differences in barrier height (or the effective work function) of up to 1 eV, which makes the electrode heterogeneity a crucial factor in designing electron devices suitable for low-voltage operation.

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Flatband voltage shift of ruthenium gated stacks and its link with the formation of a thin ruthenium oxide layer at the ruthenium/dielectric interface

Abstract: Fabrication of advanced La-incorporated Hf-silicate gate dielectrics using physical-vapor-deposition-based in situ method and its effective work function modulation of metal/high-k stacks

Cited by 22 publications

References 39 publications

Growth and thermal oxidation of Ru and ZrO2 thin films as oxidation protective layers

Growth and thermal oxidation of Ru and ZrO2 thin films as oxidation protective layers

Electron energy distribution in Si/TiN and Si/Ru hybrid floating gates with hafnium oxide based insulators for charge trapping memory devices

Internal Photoemission Metrology of Inhomogeneous Interface Barriers

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