Improvement in electrical properties and thermal stability of low-temperature-processed Hf–Al–O gate dielectrics

Essary, Chad Robert; Ramani, Karthik; Crăciun, V.; Singh, Rupali

doi:10.1063/1.2193046

Cited by 15 publications

(10 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Elements forming CRN, MCRN, or RCP all show potential to stabilize the amorphous phase of high- k dielectric thin films; thus, the choice of incorporating elements involves an optimization/compromise between a stronger amorphizer and a higher dielectric constant. The film crystallization temperatures at a particular alloying element incorporation level are reported, ,,, but it is sometimes difficult to compare these temperatures because different film thicknesses are employed.…”

Section: Introductionmentioning

confidence: 99%

Structure versus Thermal Stability: The Periodic Structure of Atomic Layer Deposition-Grown Al-Incorporated HfO₂ Films and Its Effects on Amorphous Stabilization

Wang

Ekerdt

2011

Chem. Mater.

View full text Add to dashboard Cite

Atomic layer deposition (ALD) is used to grow Al-incorporated HfO 2 to study the relationship between the film composition variations in the growth direction and thermal stability of the amorphous phase. Ten nm films with Hf:Al ALD cycle ratios equal to 3:1 and 8:1 remain amorphous up to 900 and 800 °C, respectively, and crystallize after a 30 s annealing at 950 and 850 °C, respectively. Angle-resolved X-ray photoelectron spectroscopy is used to reveal the periodicity of ALDgrown Al-incorporated HfO 2 . Generally, multiple cycles are required to realize a complete layer in ALD. Films with a Hf:Al ALD cycle ratio of g5 have a periodic HfO 2 -HfAl x O y structure, while films with a Hf:Al ALD cycle ratio of <4 appear more like homogeneous films. Increasing the thickness of a homogeneous-like film (Hf:Al = 3:1 ALD cycle ratio) from 10 to 40 nm leads to crystallization when annealed at 900 °C. Amorphous films with a periodic structure (Hf:Al = 8:1, ALD cycle ratio) do not display a dependence of crystallization on film thickness at the same 800 °C annealing condition. The factors controlling the film thermal stability are not only the overall amorphzier incorporation concentration but also how the amorphizer is distributed in the film. Changing the periodic structure of an ALD-grown Al-incorporated HfO 2 film is a potential method to tune the film thermal stability.

show abstract

Section: Introductionmentioning

confidence: 99%

Structure versus Thermal Stability: The Periodic Structure of Atomic Layer Deposition-Grown Al-Incorporated HfO₂ Films and Its Effects on Amorphous Stabilization

Wang

Ekerdt

2011

Chem. Mater.

View full text Add to dashboard Cite

show abstract

“…These two peaks of Ba 3d 5/2 commonly reported in the literature at lower and higher binding energies, denoted as α and β phases, respectively . The peak at lower binding energy resulted due to Ba atoms in the perovskite phase, whereas the peak at higher binding energydue to nonperovskite environment such as carbonates, oxides, and oxygen vacancies. − From the Ba 3d 5/2 spectra, it is evident that the intensity of the perovskite phase gradually increases with increasing sintering temperature, and the intensity reversal of the perovskite and nonperovskite phase is observed at 1350 °C. Such a gradual increase in the intensity of the perovskite phase is due to change in the Ba environment, which is a consequence of structural phase transformation with sintering temperature.…”

Section: Resultsmentioning

confidence: 92%

Electronic Structure, Chemical Bonding, and Electrocatalytic Activity of Ba(Fe_0.7Ta_0.3)O_3−δ Compounds

Ramana

Mallesham

Nair

et al. 2021

ACS Appl. Energy Mater.

View full text Add to dashboard Cite

Ba(Fe 0.7 Ta 0.3 )O 3-δ (BFTO) compounds were synthesized using a conventional, high-temperature solid-state ceramic reaction method by varying the sintering temperature (T s = 1200−1350 °C). The crystal structure, electronic structure, and electrocatalytic activity of BFTO compounds were evaluated. The processing temperature induced phase transformations and structural quality influences the electronic structure and electrocatalytic activity of BFTO compounds. At T s = 1200 °C, Ba(Fe 0.7 Ta 0.3 )O 3−δ stabilizes as a mixture of the orthorhombic + rhombohedral phase (Amm2 + R3m). With increasing T s (≥1250 °C), Ba(Fe 0.7 Ta 0.3 )O 3−δ ceramics stabilize in tetragonal + rhombohedral [P4mm + R3m] mixed phase with a variation in the number of respective phases. Highresolution X-ray photoelectron spectroscopy (XPS) of constituent elements, namely, Ba 3d, Fe 2p, Ta 4f, and O 1s levels reveals the electronic structure changes due to changes in the chemical environment resulted from structural transformation. The XPS analyses indicate that the processing temperature significantly influences the chemical environment of Fe and Ta cations in BFTO. The Ba 3d 5/2 core-level XPS spectra indicate that the perovskite phase gradually increases with increasing sintering temperature. The presence of absorption bands that are exclusively due to MO 6 stretching vibration that is connected to Ba ion as well as stretching of M−O bonds in infrared spectroscopy data indicate the structural and chemical quality of the BFTO compounds. The electrocatalytic activity of BFTO was evaluated toward hydrogen evolution reaction (HER) and oxygen reduction reaction (ORR). Though all of the samples demonstrated appreciable electrocatalytic properties, the best electrochemical catalytic activity was shown by BFTO samples sintered at 1350 °C. BFTO-1350 °C showed an onset potential of −0.690 V vs reversible hydrogen electrode (RHE) for HER and an onset potential of 0.73 V vs RHE for ORR indicating its significant electrocatalytic performance. A general increase in activity with sintering temperature is potentially due to the improved structural quality of the BFTO ceramics. In addition to offering the fundamental insights into perovskite materials based on co-doped BaTiO 3 for electrocatalysis, the present work may contribute to the design and development of materials using co-doping of different chemical valence cations for other energy-related applications.

show abstract

“…It has been previously shown that by alloying HfO 2 with Al 2 O 3 or other oxides the crystallization temperature could be increased, the structure being able to withstand much higher temperature processes without the degradation of the dielectric properties [3][4][5][6][7]. Most of such studies were performed by depositing samples containing various fractions of HfO 2 and Al 2 O 3 oxides that were submitted to different thermal anneals and then their crystallinity was assessed [7][8][9][10]. Most of such studies were performed by depositing samples containing various fractions of HfO 2 and Al 2 O 3 oxides that were submitted to different thermal anneals and then their crystallinity was assessed [7][8][9][10].…”

Section: Introductionmentioning

confidence: 99%

Microstructural Investigations of Hafnium Aluminum Oxide Films

et al. 2008

View full text Add to dashboard Cite

The crystalline structure, composition, chemical bonding and thermal stability of HfO 2 -Al 2 O 3 mixtures deposited on Si using a combinatorial pulsed laser deposition technique were investigated. After deposition some films were annealed at temperatures from 850 to 950 o C for 6 or 12 minutes. Grazing incidence x-ray diffraction investigations were performed to asses the crystallinity and thermal stability of the annealed layers. Measurements of the Al to Hf ratios were performed using energy dispersive x-ray spectroscopy and x-ray photoelectron spectroscopy. From simulations of the x-ray reflectivity and spectroscopic ellipsometry spectra the phase composition and thickness of the films was calculated and then the Al to Hf ratios. Al/Hf values of 1 and 8 were found to be necessary to block the crystallization of the films after anneals at 850 and 950 o C, respectively.

show abstract

Improvement in electrical properties and thermal stability of low-temperature-processed Hf–Al–O gate dielectrics

Cited by 15 publications

References 30 publications

Structure versus Thermal Stability: The Periodic Structure of Atomic Layer Deposition-Grown Al-Incorporated HfO₂ Films and Its Effects on Amorphous Stabilization

Structure versus Thermal Stability: The Periodic Structure of Atomic Layer Deposition-Grown Al-Incorporated HfO₂ Films and Its Effects on Amorphous Stabilization

Electronic Structure, Chemical Bonding, and Electrocatalytic Activity of Ba(Fe_0.7Ta_0.3)O_3−δ Compounds

Microstructural Investigations of Hafnium Aluminum Oxide Films

Contact Info

Product

Resources

About

Improvement in electrical properties and thermal stability of low-temperature-processed Hf–Al–O gate dielectrics

Cited by 15 publications

References 30 publications

Structure versus Thermal Stability: The Periodic Structure of Atomic Layer Deposition-Grown Al-Incorporated HfO2 Films and Its Effects on Amorphous Stabilization

Structure versus Thermal Stability: The Periodic Structure of Atomic Layer Deposition-Grown Al-Incorporated HfO2 Films and Its Effects on Amorphous Stabilization

Electronic Structure, Chemical Bonding, and Electrocatalytic Activity of Ba(Fe0.7Ta0.3)O3−δ Compounds

Microstructural Investigations of Hafnium Aluminum Oxide Films

Contact Info

Product

Resources

About

Structure versus Thermal Stability: The Periodic Structure of Atomic Layer Deposition-Grown Al-Incorporated HfO₂ Films and Its Effects on Amorphous Stabilization

Structure versus Thermal Stability: The Periodic Structure of Atomic Layer Deposition-Grown Al-Incorporated HfO₂ Films and Its Effects on Amorphous Stabilization

Electronic Structure, Chemical Bonding, and Electrocatalytic Activity of Ba(Fe_0.7Ta_0.3)O_3−δ Compounds