Investigation of thermal annealing effects on microstructural and optical properties of HfO2 thin films

Modreanu, M.; Sancho‐Parramon, Jordi; Durand, Olivier; Servet, Bernard; Stchakovsky, M.; Eypert, C.; Naudin, C.; Knowles, A.; Bridou, Françoise; Ravet, M. F.

doi:10.1016/j.apsusc.2006.06.005

Cited by 117 publications

(44 citation statements)

References 24 publications

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“…From Fig. 3a, it can be see that the two peaks located at 505 and 605 cm -1 are assigned to the monoclinic phase of HfO 2 [26], which is in good agreement with previous XRD results presented in Fig. 1.…”

Section: Resultssupporting

confidence: 91%

Annealing temperature dependence on the structural and optical properties of sputtering-grown high-k HfO2 gate dielectrics

Deng

Chen

et al. 2014

J Mater Sci: Mater Electron

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High-k gate dielectric HfO 2 thin films have been deposited on Si and quartz substrates by radio frequency magnetron sputtering. The structural characteristics, surface morphology, and optical properties of the HfO 2 /Si gate stacks at various post-annealing temperatures were examined by X-ray diffraction (XRD), atomic force microscopy (AFM), fourier transform infrared spectroscopy (FTIR), ultraviolet-visible spectroscopy (UV-Vis spectroscopy), and spectroscopic ellipsometry (SE). XRD measurement indicates that the 80 W-deposited HfO 2 films demonstrate a polycrystalline structure. AFM measurements illustrate that the root mean square of the HfO 2 thin films demonstrates an apparent increase with increasing the annealing temperature. Analysis from FTIR indicates that the Si-O-Si bonds vibration peak position shift toward lower wave numbers with increasing the annealing temperature. Combined with UV-Vis spectroscopy and SE measurements, it can be noted reduction in band gap with an increase in annealing temperature has been confirmed. Additionally, increase in refractive index (n) has been confirmed by SE.

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Section: Resultssupporting

confidence: 91%

Annealing temperature dependence on the structural and optical properties of sputtering-grown high-k HfO2 gate dielectrics

Deng

Chen

et al. 2014

J Mater Sci: Mater Electron

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“…In this figure, one can see that the found refractive index wavelength dependence of HfO 2 film is now in agreement with reference wavelength dependencies from [4]. This agreement, obtained for small layer thicknesses in multilayer and the above-mentioned differences noticed for nominal refractive index of HfO 2 having essentially larger single layer thickness, confirm the previously obtained conclusion that the crystalline state of HfO 2 depends on the film thickness [24,25]. As shown in these references, thin films are basically amorphous while thicker films are partially crystalline, with larger crystalline fraction the thicker the film.…”

Section: Application Of Multiangle Spectroscopy To Optical Characterisupporting

confidence: 88%

Optical characterization and reverse engineering based on multiangle spectroscopy

et al. 2012

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We perform characterization of thin films and reverse engineering of multilayer coatings on the basis of multiangle spectral photometric data provided by a new advanced spectrophotometer accessory. Experimental samples of single thin films and multilayer coatings are produced by magnetron sputtering and electron-beam evaporation. Reflectance and transmittance data at two polarization states are measured at incidence angles from 7 to 40 deg. We demonstrate that multiangle reflectance and transmittance data provide reliable characterization and reverse-engineering results.

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“…7d. The crystallographic evolution from an amorphous to a predominantly cubic phase is rare for HfO 2 films, as the appearance of a cubic phase is commonly accompanied by other polymorphs [52,53]. Based on this unusual crystallization behavior we suggest that the as-deposited amorphous HiTUS HfO x possesses a disordered cubic-like short-range order (i.e., the Hf atoms tend to be eightfold coordinated and the O atoms tend to be fourfold coordinated as opposed to the monoclinic coordination of seven for Hf and either three or four for O) [54].…”

Section: Hitus Filmsmentioning

confidence: 99%

High‐density remote plasma sputtering of high‐dielectric‐constant amorphous hafnium oxide films

Bayer

Hofmann

et al. 2013

Physica Status Solidi (b)

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Hafnium oxide (HfO x ) is a high dielectric constant (k) oxide which has been identified as being suitable for use as the gate dielectric in thin film transistors (TFTs). Amorphous materials are preferred for a gate dielectric, but it has been an ongoing challenge to produce amorphous HfO x while maintaining a high dielectric constant. A technique called high target utilization sputtering (HiTUS) is demonstrated to be capable of depositing high-k amorphous HfO x thin films at room temperature. The plasma is generated in a remote chamber, allowing higher rate deposition of films with minimal ion damage. Compared to a conventional sputtering system, the HiTUS technique allows finer control of the thin film microstructure. Using a conventional reactive rf magnetron sputtering technique, monoclinic nanocrystalline HfO x thin films have been deposited at a rate of $1.6 nm min À1 at room temperature, with a resistivity of 10 13 V cm, a breakdown strength of 3.5 MV cm À1 and a dielectric constant of $18.2. By comparison, using the HiTUS process, amorphous HfO x (x ¼ 2.1) thin films which appear to have a cubic-like short-range order have been deposited at a high deposition rate of $25 nm min À1 with a high resistivity of 10 14 V cm, a breakdown strength of 3 MV cm À1 and a high dielectric constant of $30. Two key conditions must be satisfied in the HiTUS system for high-k HfO x to be produced. Firstly, the correct oxygen flow rate is required for a given sputtering rate from the metallic target. Secondly, there must be an absence of energetic oxygen ion bombardment to maintain an amorphous microstructure and a high flux of medium energy species emitted from the metallic sputtering target to induce a cubiclike short range order. This HfO x is very attractive as a dielectric material for large-area electronic applications on flexible substrates.

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Investigation of thermal annealing effects on microstructural and optical properties of HfO2 thin films

Cited by 117 publications

References 24 publications

Annealing temperature dependence on the structural and optical properties of sputtering-grown high-k HfO2 gate dielectrics

Annealing temperature dependence on the structural and optical properties of sputtering-grown high-k HfO2 gate dielectrics

Optical characterization and reverse engineering based on multiangle spectroscopy

High‐density remote plasma sputtering of high‐dielectric‐constant amorphous hafnium oxide films

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