Soft x-ray photoemission studies of the HfO2/SiO2/Si system

Sayan, Şafak; Garfunkel, Eric; Süzer, Şefik

doi:10.1063/1.1450049

Cited by 163 publications

(97 citation statements)

References 13 publications

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“…This substoichiometric GeO x interfacial layer may be responsible for poor electrical properties such as high density of interface states in the ZrO 2 -and HfO 2 -on-Ge structures [3]. used to obtain the VBM values [12]. These VB offsets are in good agreement with the results recently reported by V. V. Afanas'ev et.…”

supporting

confidence: 81%

Chemical states and electronic structure of a HfO2∕Ge(001) interface

Seo

McIntyre

Sun

et al. 2005

Applied Physics Letters

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We report the chemical bonding structure and valence band alignment at the HfO2∕Ge(001) interface by systematically probing various core level spectra as well as valence band spectra using soft x rays at the Stanford Synchrotron Radiation Laboratory. We investigated the chemical bonding changes as a function of depth through the dielectric stack by taking a series of synchrotron photoemission spectra as we etched through the HfO2 film using a dilute hydrogen fluoride solution. We found that a very nonstoichiometric GeOx layer exists at the HfO2∕Ge interface. The valence band spectra near the Fermi level in each different film structure were carefully analyzed, and as a result, the valence band offset between Ge and GeOx was determined to be ΔEv (Ge–GeOx)=2.2±0.15eV, and that between Ge and HfO2, ΔEv (Ge–HfO2)=2.7±0.15eV.

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supporting

confidence: 81%

Chemical states and electronic structure of a HfO2∕Ge(001) interface

Seo

McIntyre

Sun

et al. 2005

Applied Physics Letters

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“…The Hf 4 f 7 / 2 binding energies for as-implanted and annealed samples were 17.2 eV and 17.3 eV respectively, with a splitting between the 4 f 7 / 2 and 4 f 5 / 2 peaks by 1.5 and 1.6 eV, respectively. These values were close to those reported for HfO 2 [12,13]. No shoulder in the Si 2p peak with annealing as would be indicative of a silicate [14] were detected, but Hf quantities may have been too small to detect such features.…”

supporting

confidence: 70%

Detection and mobility of hafnium in SiO2

Klenov¹,

Mates²,

Stemmer³

2006

Applied Physics Letters

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High-angle annular dark-field imaging in scanning transmission electron microscopy and x-ray photoelectron spectroscopy were used to investigate thermal SiO2 layers doped with Hf by ion implantation. Hf was mobile under the focused electron beam in the as-implanted samples. After annealing for 5min at 1200°C, clusters of crystalline HfO2 were observed that were a few nanometers in size and surrounded by residual Hf that had remained trapped in the SiO2. Hf was not mobile under the electron beam in the annealed samples. Further annealing caused an expansion of the SiO2 that was damaged by ion implantation. Hf rearrangement was confined to the ion beam damaged regions of the SiO2 layer. No diffusion of Hf into the undamaged SiO2 was observed. The implications of the results for complementary metal-oxide-semiconductor transistors with HfO2 gate dielectrics are discussed.

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“…[5][6][7][8][9] As a result, extensive use of XPS and other surface techniques have recently been reported on hafnium oxide and related systems. [6][7][8][10][11][12] Although HfO 2 has a moderately high dielectric constant and band gap ͑both useful for ultrathin dielectric applications in micro-or nano-electronics͒, charging during photon or electron irradiation can make it difficult to determine the binding energies and/or the chemical states accurately. This, in turn, may lead to incorrect assignments and conclusions.…”

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confidence: 99%