Combining Ta[sub 2]O[sub 5] and Nb[sub 2]O[sub 5] in Bilayered Structures and Solid Solutions for Use in MIM Capacitors

Matsui, Yasuhiro; Hiratani, Masahiko; Kimura, S.; Asano, Ichiro

doi:10.1149/1.1885365

Cited by 24 publications

(23 citation statements)

References 10 publications

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“…Note that the corresponding original patterns are demonstrated in Supporting information Figures S4 and S5. Owning to the same orthorhombic lattice structure, similar lattice parameters and metal ionic radius (0.74 Å) of Nb 2 O 5 and Ta 2 O 5 (Supporting information Table S4) 58 , oxidized (Nb 0.5 Ta 0.5 )C comprises 5, also confirm this phenomenon. However, the I 1(o) /I 2(m) value measured from oxidized (Hf 0.5 Nb 0.5 )C is apparently higher than that determined from (Hf 0.5 Ta 0.5 )C at each oxidation temperature, indicating a more remarkable stimulative effect of Nb than Ta.…”

Section: (I) the Phase Composition Of Carbide Solid Solutions After O...supporting

confidence: 63%

“…Note that the corresponding original patterns are demonstrated in Supporting information Figures S4 and S5. Owning to the same orthorhombic lattice structure, similar lattice parameters and metal ionic radius (0.74 Å) of Nb 2 O 5 and Ta 2 O 5 (Supporting information Table S4) 58 , oxidized (Nb 0.5 Ta 0.5 )C comprises orthorhombic (Nb x Ta 1‐x ) 2 O 5 solid solution with single‐phase and homogenous element distribution (Supporting information Figure S6), besides, at different time durations the phase remains stable, as depicted in Supporting information Figure S7. It can be concluded that compared with pristine NbC, the doping of TaC can restrain the high‐temperature transition of Nb 2 O 5 from orthorhombic to monoclinic.…”

Section: Resultsmentioning

confidence: 85%

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Low‐temperature synthesis and oxidation resistance of random combination of Hf, Nb, and Ta carbides microcuboids

Geng

Huang

et al. 2022

J Am Ceram Soc.

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Based on the dissolution‐precipitation mechanism, this article successfully synthesized binary and ternary transition metal carbide microcuboids with random combinations of Hf, Nb, and Ta by annealing monocarbides/cobalt powders. Accelerated mass transport rate through the flow of molten alloys (Co‐Hf‐Nb‐Ta) instead of slow solid diffusion made the low‐temperature pressureless sintering technique (1500°C) a reality. Furthermore, the equilibrium morphology was driven by the gradient Gibbs potential of carbides induced by the different local curvature of powders and anisotropic interfacial energy. (Hf0.5Ta0.5)C possessed the optimal oxidation resistance among all mentioned carbides, even competed with (Hf1/3Nb1/3Ta1/3)C. During the isothermal oxidation at 800∼1200°C, the doping of Nb and Ta in carbides assisted the monoclinic‐orthorhombic HfO2 transition at ambient pressure, besides, TaC can also restrain the orthorhombic‐monoclinic transition of Nb2O5. Moreover, oxidation kinetics parameters concluded that the addition of HfC and TaC contributed to the decreasing reaction order and the increasing activation energy, respectively.

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Section: (I) the Phase Composition Of Carbide Solid Solutions After O...supporting

confidence: 63%

“…Note that the corresponding original patterns are demonstrated in Supporting information Figures S4 and S5. Owning to the same orthorhombic lattice structure, similar lattice parameters and metal ionic radius (0.74 Å) of Nb 2 O 5 and Ta 2 O 5 (Supporting information Table S4) 58 , oxidized (Nb 0.5 Ta 0.5 )C comprises orthorhombic (Nb x Ta 1‐x ) 2 O 5 solid solution with single‐phase and homogenous element distribution (Supporting information Figure S6), besides, at different time durations the phase remains stable, as depicted in Supporting information Figure S7. It can be concluded that compared with pristine NbC, the doping of TaC can restrain the high‐temperature transition of Nb 2 O 5 from orthorhombic to monoclinic.…”

Section: Resultsmentioning

confidence: 85%

Low‐temperature synthesis and oxidation resistance of random combination of Hf, Nb, and Ta carbides microcuboids

Geng

Huang

et al. 2022

J Am Ceram Soc.

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“…Niobium oxide has a higher dielectric constant (ε = 53) with respect to Ta 2 O 5 but a lower band gap (∼3.3 eV). In recent papers, [1][2][3] it has been shown that the addition of small amount of Nb in tantalum based oxide decreases the crystallization temperature with small effect on the band gap value of the material. Thus, (Nb (1−x) Ta x ) 2 O 5 have been introduced in the International Technology Roadmap for Semiconductors (ITRS).…”

mentioning

confidence: 99%

Characterization of the Solid State Properties of Anodic Oxides on Magnetron Sputtered Ta, Nb and Ta-Nb Alloys

Franco

Zampardi

Santamaria

et al. 2011

J. Electrochem. Soc.

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Tantalum oxide, niobium oxide and Ta-Nb containing mixed oxides were grown by anodizing sputter-deposited Ta, Nb and Ta-Nb alloys of different compositions. A photoelectrochemical investigation was performed in order to estimate the band gap and the flat band potential of the oxides as a function of their composition. The band gap of the investigated Ta-Nb containing mixed oxides changed monotonically between those estimated for Ta 2 O 5 (4.1 eV) and Nb 2 O 5 (3.4 eV) and in agreement with a proposed correlation between the Band gap of an oxide and the difference of electronegativity of the oxide constituents. From the differential capacitance curves recorded in a wide range of electrode potential and for several frequencies of the alternative signal, the dielectric constant of the investigated oxides were estimated. © 2011 The Electrochemical Society. [DOI: 10.1149/2.031201jes] All rights reserved. Microelectronics is very important for almost all kinds of technology evolutions in the past four decades. In this area, the dielectrics science occupies a prominent place in providing the dominant technology in integrated capacitors or gate insulators. In the last years the main challenge has been to scale down the insulating oxide thickness keeping low values of the leakage current. This task has been partially achieved for metal-oxide-semiconductor field effect transistor thanks to the use of hafnium based dielectrics, while less has been done for dynamic random access memory and metal-insulator-metal capacitors (DRAM MIMCAP). To the last generation DRAM, very low (from 0.5 to 0.35 nm) equivalent thickness is required with the constraint to maintain a very low leakage current. This implies the use of material having high dielectric constant (∼50) and high band gap (>4 eV), which can be obtained by post formation thermal treatment and tuning of the oxide composition. Owing to their high value of dielectric constant, Ta 2 O 5 and Nb 2 O 5 are quite attractive oxides for the development of the next generation of DRAM. Tantalum oxide is a wide band gap (∼4 eV) material with a high dielectric constant (ε = 27 -30) if properly crystallized (T > 750• C). Niobium oxide has a higher dielectric constant (ε = 53) with respect to Ta 2 O 5 but a lower band gap (∼3.3 eV). In recent papers, 1-3 it has been shown that the addition of small amount of Nb in tantalum based oxide decreases the crystallization temperature with small effect on the band gap value of the material. Thus, (Nb (1−x) Ta x ) 2 O 5 have been introduced in the International Technology Roadmap for Semiconductors (ITRS).Tantalum-niobium mixed oxides for microelectronic components are usually prepared by high vacuum techniques (physical and chemical vapour depositions, atomic layer deposition). [4][5][6][7] In this work we propose to prepare these oxides by anodizing in suitable solutions sputter-deposited Nb-Ta alloys. This electrochemical room temperature process allows to grow oxides of controlled thickness and composition, even if a detailed investigation on t...

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“…15 It is important to understand how Ru reacts with NaIO 4 slurry solutions and forms the passivation layer. Figure 1 shows the Eh-pH diagram of the Ru-H 2 Figure 2 shows the static etch rate and passivation film thickness as a function of NaIO 4 concentration. The static etch rate and passivation film thickness of Ru increased with an increase in NaIO 4 concentrations.…”

Section: Resultsmentioning

confidence: 99%

“…For this reason, a metal-insulator-metal capacitor has been investigated. 1,2 Noble metals can be used as bottom electrodes of capacitors because they have a high work function, and thus provide a high barrier for leakage current. In addition, they are chemically very stable.…”

mentioning

confidence: 99%

Effect of Sodium Periodate in Alumina-Based Slurry on Ru CMP for Metal–Insulator–Metal Capacitor

Kim¹,

Kang²,

Kwon³

et al. 2008

Electrochem. Solid-State Lett.

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In this study, a ruthenium ͑Ru͒ chemical mechanical planarization ͑CMP͒ slurry was developed and characterized to fabricate Ru bottom electrodes in capacitor structures. Sodium periodate ͑NaIO 4 ͒ was chosen as both the oxidant and etchant due to its strong oxidizing power. The effect of NaIO 4 on Ru etching and polishing behaviors was investigated as a function of its concentration and polishing condition. The largest removal rate of 70 nm/min was obtained in a slurry of 0.1 M NaIO 4 and 2 wt % alumina particles at pH 9 and a polishing pressure of 4 psi. Planarization and isolation of each capacitor was successfully performed with the developed Ru slurry.In dynamic random access memory technology, a conventional capacitor has a semiconductor bottom electrode that is called a metal-insulator-semiconductor capacitor. However, a conventional poly-Si bottom electrode cannot satisfy the requirement of electrical properties and compatibility with high-k materials. For this reason, a metal-insulator-metal capacitor has been investigated. 1,2 Noble metals can be used as bottom electrodes of capacitors because they have a high work function, and thus provide a high barrier for leakage current. In addition, they are chemically very stable. Among different metals, Ru has been suggested as an alternative bottom electrode due to its excellent electrical performance, including a low leakage of current and compatibility with high dielectric constant materials. 3 Ru film has also been actively investigated as a Cu diffusion barrier metal for Cu interconnection due to its good electrical conductivity, immiscibility with Cu, and good adhesion property to Cu layer. 4,5 To isolate and planarize a Ru bottom electrode, dry etching technology has been widely used. 6 However, the dry etching method generates several problems such as Ru excessive recess or a loss of oxide. These problems, in turn, cause a current leakage or loss of capacitance. Therefore, a chemical mechanical planarization ͑CMP͒ process has been suggested to planarize and isolate the bottom electrode. 7 Though there is a great need for the development of a Ru CMP slurry, few studies have been carried out due to its noble properties against chemicals. If a Ru surface can form RuO 4 or RuO 2 ·2H 2 O in a chemical, it would be possible to design slurry chemistry for Ru because RuO 4 is a soluble oxide in aqueous solution. 8 In organic chemistry, periodate ion ͑IO 4 − ͒ is a well-known oxidant. 9,10 It has been reported that sodium periodate ͑NaIO 4 ͒ can form RuO 4 from hydrated ruthenic oxide ͑RuO 2 ·nH 2 O͒. 11,12 In this study, we tried to develop a stable slurry that has the characteristics of a high removal rate without a Ru attack. For this purpose, NaIO 4 was chosen for the preparation of the Ru CMP slurry. The static etch rate, passivation film thickness, and wettability were measured as functions of the slurry chemical concentration. In addition, the effect of chemicals on polishing behavior was investigated as a function of chemical concentration, abrasive parti...

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Combining Ta[sub 2]O[sub 5] and Nb[sub 2]O[sub 5] in Bilayered Structures and Solid Solutions for Use in MIM Capacitors

Cited by 24 publications

References 10 publications

Low‐temperature synthesis and oxidation resistance of random combination of Hf, Nb, and Ta carbides microcuboids

Low‐temperature synthesis and oxidation resistance of random combination of Hf, Nb, and Ta carbides microcuboids

Characterization of the Solid State Properties of Anodic Oxides on Magnetron Sputtered Ta, Nb and Ta-Nb Alloys

Effect of Sodium Periodate in Alumina-Based Slurry on Ru CMP for Metal–Insulator–Metal Capacitor

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