Thermodynamic stability of high-<i>K</i> dielectric metal oxides ZrO2 and HfO2 in contact with Si and SiO2

Gutowski, Maciej; Jaffe, John E.; Liu, Chunli; Stoker, M. W.; Hegde, Rama I.; Raghaw, S.; Tobin, Philip J.

doi:10.1063/1.1458692

Cited by 361 publications

(189 citation statements)

References 15 publications

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“…In both as grown and annealed ZrO 2 , a very clear and sharp zirconium 3d spectrum without any shoulder and broadness is obtained. The binding energy of peak is 182.3 eV, which is well consistent with reported values for zirconium oxide [11]. The spectrum can be deconvoluted by only one sub-peak that spin orbit splitting is 2.4 eV.…”

Section: Resultssupporting

confidence: 75%

Electronic Structure of Ce-doped ZrO₂Film: Study of DFT Calculation and Photoelectron Spectroscopy

Jeong

Song

Lim

et al. 2016

Applied Science and Convergence Technology

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In this study, we evaluated the change of electronic structure during redox process in cerium-doped ZrO 2 grown by sol gel method. By sol-gel method, we could obtain cerium-doped ZrO 2 in high oxygen partial pressure and low temperature. After post annealing process in nitrogen ambient, the film is deoxidized. We used spectroscopic and theoretical methods to analysis change of electronic structure. X-ray absorption spectroscopy (XAS) for O K1-edge and Density Functional Theory (DFT) calculation using VASP code were performed to verify the electronic structure of the film. Also, high resolution x-ray photoelectron spectroscopy (HRXPS) for Ce 3d was carried out to confirm chemical bond of cerium doped ZrO 2 . Through the investigation of the electronic structure, we verified as followings.(1) During reduction process, binding energy of oxygen is increase. Simultaneously, oxidation state of cerium was change to 4+ to 3+. (2) Cerium 4+ and cerium 3+ states were generated at different energy level. (3) Absorption states in O K edge were mainly originated by Ce 4+ f 0 and Ce 3+, while occupied states in valance band were mainly originated from Ce 4+ f 2 .

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Section: Resultssupporting

confidence: 75%

Electronic Structure of Ce-doped ZrO₂Film: Study of DFT Calculation and Photoelectron Spectroscopy

Jeong

Song

Lim

et al. 2016

Applied Science and Convergence Technology

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“…Some rare-earth elements such as lanthanides also have good properties but they are hygroscopic [19][20][21]. Generally, lanthanides are incorporated into Hf-based high-k layers to improve the performance, for instance, the k value and crystallization temperature.…”

Section: Fb Modulation With Rare Earth Doping In Nmosmentioning

confidence: 99%

Interface dipole engineering in metal gate/high-k stacks

et al. 2012

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Although metal gate/high-k stacks are commonly used in metal-oxide-semiconductor field-effect-transistors (MOSFETs) in the 45 nm technology node and beyond, there are still many challenges to be solved. Among the various technologies to tackle these problems, interface dipole engineering (IDE) is an effective method to improve the performance, particularly, modulating the effective work function (EWF) of metal gates. Because of the different electronegativity of the various atoms in the interfacial layer, a dipole layer with an electric filed can be formed altering the band alignment in the MOS stack. This paper reviews the interface dipole formation induced by different elements, recent progresses in metal gate/high-k MOS stacks with IDE on EWF modulation, and mechanism of IDE. high-k dielectrics, metal gate, interface dipole, MOS stack, effective work function Citation:Huang A P, Zheng X H, Xiao Z S, et al. Interface dipole engineering in metal gate/high-k stacks. Chin Sci Bull, 2012, 57: 28722878, doi: 10.1007/s11434-012-5289-6As poly-Si/SiO 2 is replaced by metal gate/high-k stacks in the 45 nm MOS technological node and beyond, the interface becomes more complicated and there are still many challenges to be solved [1,2], such as the flatband voltage shift (V fb shift) [3]. Hence, the properties of the high-k layer must be reconsidered carefully. It has recently been reported that the interface dipole can induce potential difference across the interface and change the band alignment of the MOS stack, and this phenomenon can be exploited to modulate the V fb shift [4][5][6]. Elemental doping can also improve the performance of the high-k layer. Interface dipole engineering (IDE) by varying the dopants or inserting capping layers has attracted much attention in MOS technology. Not only can this technique control the V fb shift, but also the properties of the high-k dielectrics can be improved [7]. This paper reviews the formation of interface dipole, recent research progresses on IDE and effective work function (EWF) modulation, as well as mechanism of IDE in metal gate/high-k MOS stacks. Interface dipole formation in MOS stackTo control the threshold voltage (V th ), work function of a metal gate should be near the conduction band of Si (~4.3 eV) for nMOS and valence band (~5.2 eV) for pMOS. However, only very few metals can satisfy these requirements and furthermore, when a metal is in contact with the high-k layer, its Fermi-level will tend to be at the neutral level of the high-k layer. This phenomenon is called Fermi-level pinning (FLP) which causes EWF of the nMOS (pMOS) to be much greater (smaller) than the corresponding work function in vacuum [8]. The electron density in the metal gate can also influence the EWF [9]. Stacked metal layers used in the gate structure have been investigated. Misra et al. [10] reported that a metal gate stack using Ru-Ta alloys could yield a work function compatible with nMOS. Lin et al. [11] implanted N into a Mo gate that was

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“…[10][11][12][13][14][15] The thermal stability of high-materials in direct contact with Si and SiO 2 has also emerged as a key issue in selecting suitable high-candidates. The thermal stability of HfO 2 films in contact with Si and SiO 2 has been studied for HfO 2 deposited by atomic layer deposition ͑ALD͒, 16 ion beam assisted deposition, 17 metalorganic chemical vapor deposition, 18 and jet vapor deposition ͑JVD͒. 12 The as-deposited structure of HfO 2 films is also at issue.…”

Section: Introductionmentioning

confidence: 99%

Morphology and crystallization kinetics in HfO2 thin films grown by atomic layer deposition

Gong

Wilk³

et al. 2003

Journal of Applied Physics

162

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We report the effects of annealing on the morphology and crystallization kinetics for the high-gate dielectric replacement candidate hafnium oxide (HfO 2 ). HfO 2 films were grown by atomic layer deposition ͑ALD͒ on thermal and chemical SiO 2 underlayers. High-sensitivity x-ray diffractometry shows that the as-deposited ALD HfO 2 films on thermal oxide are polycrystalline, containing both monoclinic and either tetragonal or orthorhombic phases with an average grain size of ϳ8.0 nm. Transmission electron microscopy shows a columnar grain structure. The monoclinic phase predominates as the annealing temperature and time increase, with the grain size reaching ϳ11.0 nm after annealing at 900°C for 24 h. The crystallized fraction of the film has a strong dependence on annealing temperature but not annealing time, indicating thermally activated grain growth. As-deposited ALD HfO 2 films on chemical oxide underlayers are amorphous, but show strong signatures of ordering at a subnanometer level in Z-contrast scanning transmission electron microscopy and fluctuation electron microscopy. These films show the same crystallization kinetics as the films on thermal oxide upon annealing.

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Thermodynamic stability of high-K dielectric metal oxides ZrO2 and HfO2 in contact with Si and SiO2

Cited by 361 publications

References 15 publications

Electronic Structure of Ce-doped ZrO₂Film: Study of DFT Calculation and Photoelectron Spectroscopy

Electronic Structure of Ce-doped ZrO₂Film: Study of DFT Calculation and Photoelectron Spectroscopy

Interface dipole engineering in metal gate/high-k stacks

Morphology and crystallization kinetics in HfO2 thin films grown by atomic layer deposition

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Thermodynamic stability of high-K dielectric metal oxides ZrO2 and HfO2 in contact with Si and SiO2

Cited by 361 publications

References 15 publications

Electronic Structure of Ce-doped ZrO2Film: Study of DFT Calculation and Photoelectron Spectroscopy

Electronic Structure of Ce-doped ZrO2Film: Study of DFT Calculation and Photoelectron Spectroscopy

Interface dipole engineering in metal gate/high-k stacks

Morphology and crystallization kinetics in HfO2 thin films grown by atomic layer deposition

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Product

Resources

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Electronic Structure of Ce-doped ZrO₂Film: Study of DFT Calculation and Photoelectron Spectroscopy

Electronic Structure of Ce-doped ZrO₂Film: Study of DFT Calculation and Photoelectron Spectroscopy