The role of nitrogen-related defects in high-k dielectric oxides: Density-functional studies

Gavartin, J. L.; Foster, Adam S.; Bersuker, G.; Shluger, Alexander L.

doi:10.1063/1.1854210

Cited by 155 publications

(118 citation statements)

References 45 publications

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“…18 For high nitrogen concentration, however, the nitrogen incorporation generates nitrogen related defects, leading to an increase in interface state rather than reducing it. 17 Similar interpretation can be applied for the dependency of nitrogen content on V FB and hysteresis shown in Fig. 2͑a͒.…”

Section: Resultsmentioning

confidence: 99%

The effects of nitrogen profile and concentration on negative bias temperature instability of plasma enhanced atomic layer deposition HfOxNy prepared by in situ nitridation

Maeng

2008

Journal of Applied Physics

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Articles you may be interested inDependences of nitrogen incorporation behaviors on the crystallinity and phase distribution of atomic layer deposited Hf-silicate films with various Si concentrations J. Appl. Phys. 104, 054101 (2008) We have prepared plasma enhanced atomic layer deposition HfO x N y thin films by in situ nitridation using nitrogen/oxygen mixture plasma and studied the effects of nitrogen contents and profiles on the negative bias temperature instability ͑NBTI͒. The nitrogen depth profiles and concentrations were controlled by changing the exposure sequences and the nitrogen to oxygen flow ratio, respectively. The best immunity to NBTI degradations was obtained for the nitrogen to oxygen ratio of 2:1 when nitrogen atoms are incorporated away from the high k / Si interface. We propose a dielectric degradation mechanism based on the reaction-diffusion model in which nitrogen plays a role of hydrogen generator at the interface and diffusion barrier in the bulk film.

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Section: Resultsmentioning

confidence: 99%

The effects of nitrogen profile and concentration on negative bias temperature instability of plasma enhanced atomic layer deposition HfOxNy prepared by in situ nitridation

Maeng

2008

Journal of Applied Physics

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“…Gavartin et al (2005) calculate a particularly high value (−2.7 eV) in HfO 2 -somewhat larger than the −1.6 eV of Kang et al (2004), though with a similar pinning level in the gap. These authors also find hydrogen to constitute a shallow donor when complexed with an oxygen vacancy in monoclinic hafnia.…”

Section: Theoretical Predictionsmentioning

confidence: 99%

Oxide muonics: II. Modelling the electrical activity of hydrogen in wide-gap and high-permittivity dielectrics

Cox

Gavartin

Lord

et al. 2006

J. Phys.: Condens. Matter

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Following the prediction and confirmation that interstitial hydrogen forms shallow donors in zinc oxide, inducing electronic conductivity, the question arises as to whether it could do so in other oxides, not least in those under consideration as thin-film insulators or high-permittivity gate dielectrics. We have screened a wide selection of binary oxides for this behaviour, therefore, using muonium as an accessible experimental model for hydrogen. New examples of the shallow-donor states that are required for n-type doping are inferred from hyperfine broadening or splitting of the muon spin rotation spectra. Electron effective masses are estimated (for several materials where they are not previously reported) although polaronic rather than hydrogenic models appear in some cases to be appropriate. Deep states are characterized by hyperfine decoupling methods, with new examples found of the neutral interstitial atom even in materials where hydrogen is predicted to have negative-U character, as well as a highly anisotropic deep-donor state assigned to a muonium-vacancy complex. Comprehensive data on the thermal stability of the various neutral states are given, with effective ionization temperatures ranging from 10 K for the shallow to over 1000 K for the deep states, and corresponding activation energies between tens of meV and several eV. A striking feature of the systematics, rationalized in a new model, is the preponderance of shallow states in materials with band-gaps less below 5 eV, atomic states above 7 eV, and their coexistence in the intervening threshold range, 5-7 eV.

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“…10 In standard MOSFET fabrication, defects in SiO 2 are passivated by hydrogen, but in HfO 2 this causes as many problems as it solves. 11 Various other postdeposition treatments have been tried, especially nitrogen-based, 12 but with little success in reducing fixed charge in the insulator.…”

Section: Introductionmentioning

confidence: 99%

Interfacial oxide growth at silicon∕high-k oxide interfaces: First principles modeling of the Si–HfO2 interface

Hakala

Foster

Gavartin

et al. 2006

Journal of Applied Physics

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We have performed first principles calculations to investigate the structure and electronic properties of several different Si-HfO x interfaces. The atomic structure has been obtained by growing HfO x layer by layer on top of the Si͑100͒ surface and repeatedly annealing the structure using ab initio molecular dynamics. The interfaces are characterized via their geometric and electronic properties, and also using electron transport calculations implementing a finite element based Green's function method. We find that in all interfaces, oxygen diffuses towards the interface to form a silicon dioxide layer. This results in the formation of dangling Hf bonds in the oxide, which are saturated either by hafnium diffusion or Hf-Si bonds. The generally poor performance of these interfaces suggests that it is important to stabilize the system with respect to lattice oxygen diffusion.

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The role of nitrogen-related defects in high-k dielectric oxides: Density-functional studies

Cited by 155 publications

References 45 publications

The effects of nitrogen profile and concentration on negative bias temperature instability of plasma enhanced atomic layer deposition HfOxNy prepared by in situ nitridation

The effects of nitrogen profile and concentration on negative bias temperature instability of plasma enhanced atomic layer deposition HfOxNy prepared by in situ nitridation

Oxide muonics: II. Modelling the electrical activity of hydrogen in wide-gap and high-permittivity dielectrics

Interfacial oxide growth at silicon∕high-k oxide interfaces: First principles modeling of the Si–HfO2 interface

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