Atomic-layer deposition of ZrO2 with a Si nitride barrier layer

Nakajima, Akira; Kidera, Toshirou; Ishii, Hiroyuki; Yokoyama, Shiyoshi

doi:10.1063/1.1510584

Cited by 35 publications

(22 citation statements)

References 18 publications

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“…[15±17] In an effort to avoid these problems, metal alkoxides such as zirconium tert-butoxide, Zr(O t Bu) 4 have been examined for use in the ALD of ZrO 2 . [18,19] Some papers also report the CVD [20] or ALD-like [21] growth of ultrathin HfO 2 films using hafnium tert-butoxide and oxygen, in which temperatures above 350 C have been used. In ALD, the use of tert-butoxides is problematic because of their easy decomposition which destroys the self-limiting growth mechanism.…”

Section: Introductionmentioning

confidence: 98%

Atomic Layer Deposition of Hafnium Dioxide Films Using Hafnium Bis(2‐butanolate)bis(1‐methoxy‐2‐methyl‐2‐propanolate) and Water

Kukli

Ritala

Leskelä

et al. 2003

Chemical Vapor Deposition

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HfO 2 films were grown by atomic layer deposition (ALD) from a mononuclear Hf(O t Bu) 2 (OCMe 2 CH 2 OMe) 2 complex and H 2 O at temperatures in the range 275±400 C on borosilicate glass and Si(100) substrates. The growth of the densest films was achieved at temperatures above 300 C. The growth rate was influenced by the thermal decomposition of the Hf precursor. The as-deposited films were oxides with an O:Hf ratio of 2.0 ± 0.2, although containing large amounts of impurities. Crystalline monoclinic films were grown at temperatures exceeding 325 C, whereas at lower temperatures the films mostly remained amorphous. On the whole, the refractive index of the films varied between 1.95 and 2.00. The effective permittivities of the dielectrics in Al/HfO 2 /p-Si(100) capacitor structures varied between 12 and 14, slightly increasing with growth temperature.

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Section: Introductionmentioning

confidence: 98%

Atomic Layer Deposition of Hafnium Dioxide Films Using Hafnium Bis(2‐butanolate)bis(1‐methoxy‐2‐methyl‐2‐propanolate) and Water

Kukli

Ritala

Leskelä

et al. 2003

Chemical Vapor Deposition

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“…10,17 To suppress this, different barrier layers such as ultrathin nitride layers have been employed. 18 On the other hand, interfacial zirconium silicate, which has higher permittivity than 3.9 of SiO 2 , has been suggested to form a͒ Author to whom correspondence should be addressed; electronic mail: matti.putkonen@hut.fi b͒ Also at: University of Tartu, Institute of Experimental Physics and Technology, Tähe 4, EE-51010 Tartu, Estonia.…”

Section: Introductionmentioning

confidence: 99%

Structural and dielectric properties of thin ZrO2 films on silicon grown by atomic layer deposition from cyclopentadienyl precursor

Niinistö¹,

Putkonen²,

Niinistö³

et al. 2004

Journal of Applied Physics

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ZrO 2 thin films with thicknesses below 20 nm were deposited by the atomic layer deposition process on Si(100) substrates at 350 °C. An organometallic precursor, Cp2Zr(CH3)2 (Cp=cyclopentadienyl, C5H5) was used as the zirconium source and water or ozone as oxygen source. The influence of oxygen source and substrate pretreatment on the dielectric properties of ZrO2 films was investigated. Structural characterization with high-resolution transmission electron microscopy was performed to films grown onto HF-etched or native oxide covered silicon. Strong inhibition of ZrO2 film growth was observed with the water process on HF-etched Si. Ozone process on HF-etched Si resulted in interfacial SiO2 formation between the dense and uniform film and the substrate while water process produced interfacial layer with intermixing of SiO2 and ZrO2. The effective permittivity of ZrO2 in Al/ZrO2/Si/Al capacitor structures was dependent on the ZrO2 layer thickness and oxygen source used. The interfacial layer formation increased the capacitance equivalent oxide thickness (CET). CET of 2.0 nm was achieved with 5.9 nm ZrO2 film deposited with the H2O process on HF-stripped Si. The ozone-processed films showed good dielectric properties such as low hysteresis and nearly ideal flatband voltage. The leakage current density was lower and breakdown field higher for the ozone-processed ZrO2 films.

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“…It also requires a relatively high deposition temperature. [2][3][4][5] However, low-temperature deposition is becoming important in applications to flexible and light plastic electronic devices. For low-temperature applications, plasma-enhanced ALD ͑PEALD͒ is a promising deposition technique.…”

mentioning

confidence: 99%

PEALD of Zirconium Oxide Using Tetrakis(ethylmethylamino)zirconium and Oxygen

Yun

Lim

Lee

2004

Electrochem. Solid-State Lett.

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Highly uniform ZrO 2 films were deposited by plasma enhanced atomic layer deposition ͑PEALD͒ using tetrakis͑ethylmethylami-no͒zirconium ͑TEMAZ͒ and O 2 as precursors. The deposition rates were 0.14 and 0.11 nm/cycle at temperatures of 110 and 250°C, respectively. ZrO 2 films deposited at 150°C contained ϳ3% nitrogen, incorporated from the Zr-precursor, which contains four amino-groups. In the absence of a plasma, a ZrO 2 film was not deposited with TEMAZ and O 2 at 150°C. The electrical characteristics including breakdown strength and permitivity were also evaluated. The permitivities for 110°C-and 200°C-ZrO 2 films were 16.1 and 26.9, respectively. Dielectric materials with high permitivity ͑͒ as a substitute for SiO 2 have been extensively examined, as SiO 2 layers thinner than 1.5 nm cannot be used as a gate dielectric in sub-0.1 micrometer metal oxide semiconductor technology due to its high tunneling current which exceeds 1 A/cm 2 at 1 V. 1 The possibility of using highdielectrics, such as ZrO 2 and HfO 2 , etc., has recently been widely investigated due to dielectric constants that are much higher than that of SiO 2 and lower leakage currents far below that of an equivalent SiO 2 layer. The high-material as a gate dielectric or a capacitor is also an emerging issue in the fabrication of high current and high mobility thin film transistors for display applications.Among the available thin film deposition techniques, thin highdielectric films can be uniformly deposited using chemical vapor deposition ͑CVD͒ and atomic layer deposition ͑ALD͒ techniques. The ALD technique is based on the alternating exposure of a surface to two or more gas phase precursors and self-limiting surface reactions between the sequentially adsorbing precursors. Thus, ALD is known to be superior to CVD because of its extraordinarily good conformality and precise thickness control. Conventional ALD typically involves the use of metal chloride precursors such as HfCl 4 and ZrCl 4 , etc. and several oxygen precursors including H 2 O, ozone, and alkoxides for depositing oxide films in combination with the metal chlorides. It also requires a relatively high deposition temperature. 2-5 However, low-temperature deposition is becoming important in applications to flexible and light plastic electronic devices. For low-temperature applications, plasma-enhanced ALD ͑PEALD͒ is a promising deposition technique. 6-8 The use of an O 2 plasma in ALD enhances the deposition rate and electrical properties as well as film density compared to those of conventional ALD.In this paper, the deposition and characteristics of high-ZrO 2 films are reported for low-temperature applications including thin film transistor on a plastic substrate. The deposition of ZrO 2 films was carried out for the first time by PEALD using tetrakis͑ethylm-ethylamino͒zirconium ͓Zr͕N(C 2 H 5 )(CH 3 )͖ 4 , TEMAZ͔ as a Zrprecursor and an O 2 plasma as the oxidant. The effect of deposition temperature was first investigated on the material characteristics of ZrO 2 at temperatures rangin...

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Atomic-layer deposition of ZrO2 with a Si nitride barrier layer

Cited by 35 publications

References 18 publications

Atomic Layer Deposition of Hafnium Dioxide Films Using Hafnium Bis(2‐butanolate)bis(1‐methoxy‐2‐methyl‐2‐propanolate) and Water

Atomic Layer Deposition of Hafnium Dioxide Films Using Hafnium Bis(2‐butanolate)bis(1‐methoxy‐2‐methyl‐2‐propanolate) and Water

Structural and dielectric properties of thin ZrO2 films on silicon grown by atomic layer deposition from cyclopentadienyl precursor

PEALD of Zirconium Oxide Using Tetrakis(ethylmethylamino)zirconium and Oxygen

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