Highly Reliable Thin Hafnium Oxide Gate Dielectric

Kang, Laegu; Lee, Byoung-Hun; Qi, Wenjie; Jeon, Young‐Jin; Nieh, R.; Gopalan, Sundararaman; Onishi, K.; Lee, Jack C.

doi:10.1557/proc-592-81

Cited by 15 publications

(13 citation statements)

References 5 publications

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“…Because the SiO x rich Hf silicate interface layer has a lower k value than the bulk Zr-doped HfO 2 layer, e.g., 7 vs 24, the effective dielectric constant of the high-k/ interface stack decreases with the increase of the PDA O 2 concentration. 17,22 The low J leakage at the high PDA O 2 concentration is consistent with the EOT change. The interface layer structure also plays an important role in decreasing J leakage .…”

Section: Methodsmentioning

confidence: 54%

“…The increase of the SiO x rich silicate interface with the increase of O 2 concentration in the PDA atmosphere is consistent with the interface formation mechanism, i.e., oxygen diffusion through the bulk high-k film to the interface. [17][18][19] The Hf 4f 7/2 peak binding energy in these samples also increased slightly with the decrease of the O 2 concentration in PDA atmosphere, i.e., 18.1, 18.3, and 18.5 eV in Fig. 1a-c, respectively.…”

Section: Methodsmentioning

confidence: 77%

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Zirconium-Doped Hafnium Oxide High-k Dielectrics with Subnanometer Equivalent Oxide Thickness by Reactive Sputtering

Yan

Kuo

Lü

2007

Electrochem. Solid-State Lett.

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Ultrathin zirconium-doped hafnium oxide high dielectric constant films, e.g., with an equivalent oxide thickness less than 1 nm, have been prepared by high-power sputtering and low oxygen content annealing conditions on the p-type Si͑100͒ substrate. The influence of the process conditions on the film's material and electrical properties were investigated with X-ray photoelectron spectroscopy analysis and electrical measurements. The low equivalent oxide film also shows a small charge trapping density, a low leakage current density, and a moderate interface state density. This is a viable gate dielectric film for future complementary metal oxide semiconductor devices.The continuous shrinkage of complementary metal oxide semiconductor ͑CMOS͒ device dimensions necessitates the use of a high dielectric constant ͑high-k͒ gate dielectric material to replace the thermal grown silicon dioxide ͑SiO 2 ͒. 1 Metal oxides such as hafnium oxide ͑HfO 2 ͒ and zirconium oxide ͑ZrO 2 ͒ have been extensively studied as the high-k gate dielectric candidates because of their high k values, large electron band offsets to silicon, and good thermal stability in contact with silicon. 2-5 However, both HfO 2 and ZrO 2 crystallize at a relatively low temperature, Ͻ700°C, which is a potential reliability problem. Previously, it was demonstrated that many physical and electrical properties of a metal oxide high-k gate dielectric, such as the amorphous-to-polycrystalline transition temperature, interface layer quality, k value, dielectric breakdown strength, and leakage current density, could be improved by the doping method, i.e., adding a third element into the film. 6-9 For example, the zirconium-doped hafnium oxide ͑Zr-doped HfO 2 ͒ dielectric showed a lower equivalent oxide thickness ͑EOT͒ and smaller interface state density ͑D it ͒ than the undoped HfO 2 . 8 This result is consistent whether the high-k film was deposited by sputtering or atomic layer deposition ͑ALD͒. 8,9 The recent work on the ALD Zr-doped HfO 2 high-k dielectric film demonstrated that the addition of ZrO 2 into HfO 2 would not only help to partially stabilize the tetragonal structure of HfO 2 but also improve the surface morphology of the high-k film, both of which play critical roles in improving device characteristics. 10 Previously, it was reported that a proper amount of dopant in the high-k film can increase its crystallization temperature. 11 The Zr-doped HfO 2 dielectric film in this work is amorphous. 12 In general, the amorphous high-k dielectrics are desirable for uniform dielectric properties and reliability concerns. 1 According to the International Technology Roadmap for Semiconductor ͑ITRS͒, a high-k gate dielectric film with an EOT less than 1 nm will be required for future CMOS applications. 13 In this paper, we have investigated the feasibility of preparing such a gate dielectric by the reactive sputtering method as well as the influences of process conditions to the high-k film's dielectric properties. ExperimentalThe Zr-doped HfO 2 thin film was dep...

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Section: Methodsmentioning

confidence: 54%

Section: Methodsmentioning

confidence: 77%

Zirconium-Doped Hafnium Oxide High-k Dielectrics with Subnanometer Equivalent Oxide Thickness by Reactive Sputtering

Yan

Kuo

Lü

2007

Electrochem. Solid-State Lett.

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“…For example, the dielectric constant of the interfacial layer is estimated to be greater than that of SiO 2 by a factor of 1.6 12 or 2. 11 Incorporation of nitrogen in interfacial SiO 2 layers has been shown to be beneficial in Si-based microelectronic devices and model device systems. For example, N-(Siϵ) 3 bonds reduce strain at SiO 2 /Si interfaces, making defect relief unnecessary and thereby minimizing charge traps.…”

Section: Introductionmentioning

confidence: 99%

“…and the interfacial nitride is ϳ1 ML based on XPS measurements; k for the HfO 2 /Si interfacial material has been estimated in the literature 11. Using electrical and TEM measurements, Kang et al11 estimate k HfSi x O y ϳ2ϫk SiO 2 ϳ8.…”

mentioning

confidence: 99%

Electrical and spectroscopic comparison of HfO2/Si interfaces on nitrided and un-nitrided Si(100)

Kirsch

Kang

Lozano

et al. 2002

Journal of Applied Physics

257

149

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Thermal decomposition behavior of the HfO 2 / SiO 2 / Si system J. Appl. Phys. 94, 928 (2003); 10.1063/1.1578525 Interfacial properties of ZrO 2 on silicon J. Appl. Phys. 93, 5945 (2003); 10.1063/1.1563844Yttrium silicate formation on silicon: Effect of silicon preoxidation and nitridation on interface reaction kineticsThe interfacial chemistry of the high-k dielectric HfO 2 has been investigated on nitrided and un-nitrided Si͑100͒ using x-ray photoelectron spectroscopy ͑XPS͒ and secondary ion mass spectroscopy ͑SIMS͒. The samples are prepared by sputter depositing Hf metal and subsequently oxidizing it. A 600°C densification anneal is critical to completing Hf oxidation. These spectroscopic data complement electrical testing of metal oxide semiconductor capacitors fabricated with ϳ50 Å HfO 2 on nitrided and un-nitrided Si͑100͒. Capacitors with interfacial nitride show reduced leakage current by a factor of 100 at a Ϫ1 V bias. Concurrently, interfacial nitride increased capacitance 12% at saturation. XPS shows that an interfacial layer composed of nonstoichiometric hafnium silicate (HfSi x O y ), forms at both the HfO 2 /Si and HfO 2 /SiN x interfaces. Differences in the Si 2p and O 1s XP spectra suggest more silicate forms at the un-nitrided interface. HfO 2 films on un-nitrided Si show more O 1s and Si 2p photoemission intensity characteristic of HfSi x O y . SIMS depth profiles through the buried interface are consistent with interfacial silicate formation, as shown by a HfSiO ϩ ion signal, that is sandwiched between HfO 2 and SiN x . SiN x is suggested to minimize interfacial HfSi x O y formation by limiting the amount of Si available to interact with the HfO 2 layer.

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“…However, during the deposition an interfacial layer between HfO 2 and Si was often observed [4][5][6]. The thickness of this interfacial layer varies from 9 Å to 1300 Å and its presence becomes critical for device performance.…”

Section: Introductionmentioning

confidence: 99%

Reactively sputtered hafnium oxide on silicon dioxide: Structural and electrical properties

Kolkovsky

Lukat

Kurth

et al. 2015

Solid-State Electronics

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Highly Reliable Thin Hafnium Oxide Gate Dielectric

Cited by 15 publications

References 5 publications

Zirconium-Doped Hafnium Oxide High-k Dielectrics with Subnanometer Equivalent Oxide Thickness by Reactive Sputtering

Zirconium-Doped Hafnium Oxide High-k Dielectrics with Subnanometer Equivalent Oxide Thickness by Reactive Sputtering

Electrical and spectroscopic comparison of HfO2/Si interfaces on nitrided and un-nitrided Si(100)

Reactively sputtered hafnium oxide on silicon dioxide: Structural and electrical properties

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