Formation of Reliable HfO2/HfSixOyGate-Dielectric for Metal-Oxide-Semiconductor Devices

Quan, Yong Chun; Lee, Jang Eun; Kang, Hyeoksu; Roh, Yonghan; Jung, Donggeun; Yang, Cheol‐Woong

doi:10.1143/jjap.41.6904

Cited by 26 publications

(14 citation statements)

References 3 publications

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“…The basic concept for using highdielectric-constant materials is increasing the film thickness to reduce the tunneling leakage current and improve the reliability while scaling the capacitance equivalent oxide thickness (CET) below the direct tunneling limit of SiO 2 . Rare earth oxides have received much attention due to their many advantages: high dielectric constant, [3][4][5] sufficiently high breakdown strength, extremely low leakage current, and well-behaved interface properties. Rare earth oxides, 6,7) such as 9) Ta 2 O 5 10) and Gd 2 O 3 11,12) have been studied.…”

Section: Introductionmentioning

confidence: 99%

Properties of Thermal Gadolinium Oxide Films on Silicon

Ko¹,

Chang

Jeng

et al. 2005

Jpn. J. Appl. Phys.

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The formation and electrical characteristics of thermal gadolinium (Gd) oxide films were investigated. A good uniform interface formed by proper treatment was observed by transmission electron microscopy (TEM) examination. The dielectric constant of the thermal Gd oxide films was approximately 10 from capacitance-voltage measurements. The X-ray diffraction (XRD) pattern of the thermal Gd oxide (Gd 2 O 3 ) films showed that they had a cubic structure. The Gd oxides that were oxidized at higher temperatures exhibited smaller grain boundaries than those oxidized at lower temperatures. The grain boundary size of the Gd oxides significantly affects the leakage property. A good Gd oxide quality can be obtained when the thermal oxidation temperature is above 900 C.

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Section: Introductionmentioning

confidence: 99%

Properties of Thermal Gadolinium Oxide Films on Silicon

Ko¹,

Chang

Jeng

et al. 2005

Jpn. J. Appl. Phys.

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“…7 For a typical operation voltage of 1-1.5 V, the leakage current through HfO 2 dielectric films was found to be several orders of magnitude lower than that of SiO 2 for the same equivalent oxide thickness of 0.9-2 nm. [8][9][10] However, clearly a weak point in using thermally grown or vapour phase deposited HfO 2 as gate dielectrics arises from its poor interfacing with semiconductors which has led to a fervent investigation of hafnium-based complex oxides in recent years. 7 Nowadays it is common knowledge that the anodic oxides on valve metals (e.g.…”

mentioning

confidence: 99%

Anodization Behavior of Glassy Metallic Hafnium Thin Films

Mardare

Siket

Gavrilović-Wohlmuther

et al. 2015

J. Electrochem. Soc.

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Glassy metallic Hf thin films were obtained using electron beam deposition at room temperature due to the low energy received by Hf atoms during the film formation process. The amorphous nature of the Hf films suggested by XRD was confirmed by low temperature electrical conductivity measurements where a negative temperature coefficient of resistivity was identified. Anodic oxidations using a scanning droplet cell microscopy were performed on a typical crystalline (hexagonal) Hf film obtained by sputtering and on the glassy Hf. A decrease of the oxide formation factor by 30% (from 2.4 to 1.7 nm V −1 ) was evidenced on the amorphous Hf. Electrochemical impedance spectroscopy on both samples revealed almost identical capacitances while the electrical permittivities were found to differ by 40%. The dielectric constant of the HfO 2 decreased from 33.5 on the crystalline parent metal sample to 19.8 on the amorphous one. The unexpected 10% deviation was attributed to a smoother defect-free oxide/metal interface in the case of Hafnium dioxide has a high dielectric constant, a relatively large bandgap, larger heat of formation as compared to SiO 2 , good chemical and thermal stability on Si and large barrier heights at interfaces with Si. Its modern applications are diverse, most recent ones focused on electronic devices. The chosen methods for obtaining hafnia thin films are also varied, most common one being reactive sputtering.1 Doping of sputtered hafnia with elements such as Ce has led to an increase in the dielectric constant and a decrease of the leakage currents, while Si doping revealed intrinsic ferroelectricity due to a non-centrosymmetric orthorhombic phase with direct applications in ferroelectric memories.2,3 Cathodoluminescence due to oxygen vacancies was also recently found in ion beam sputtered HfO 2 and first steps toward fabrications of hafnia micro-light emitting devices were already taken. 4,5 The resistance switching behavior due to formation and rupture of conductive paths within HfO 2 deposited by atomic layer deposition was exploited for random access memory fabrication. 6 Since these are only a few examples of most recent applications of HfO 2 , still the predominant effort is put into using it as high-k material for gate oxides for replacing SiO 2 gates in MOS-FET structures.7 For a typical operation voltage of 1-1.5 V, the leakage current through HfO 2 dielectric films was found to be several orders of magnitude lower than that of SiO 2 for the same equivalent oxide thickness of 0.9-2 nm.8-10 However, clearly a weak point in using thermally grown or vapour phase deposited HfO 2 as gate dielectrics arises from its poor interfacing with semiconductors which has led to a fervent investigation of hafnium-based complex oxides in recent years. 7Nowadays it is common knowledge that the anodic oxides on valve metals (e.g. Al, Hf, Ta, Nb etc.) are some of the most compact oxides available due to their growth mechanism obeying a high field regime.11 However, their use for electronic devices is weakly ex...

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“…This SiO x formation may degrade the dielectric constant of Hf-Zr mixed oxide/Hf-Zr silicate (SiO x ) gate dielectric stack. It has been known that high-k gate dielectrics such as HfO 2 and ZrO 2 can change their structure from amorphous to poly-crystalline at relatively low temperature (i.e., 400-500°C) [4][5][6]15,16]. In Fig.…”

Section: Resultsmentioning

confidence: 99%

“…On the other hand, HfO 2 and ZrO 2 can easily crystallize at relatively low temperatures. Previously, our group demonstrated that the oxidation of the Hf thin film deposited on the Si substrate results in the HfO 2 /HfSi x O y stack layer [4,5]. In Refs.…”

Section: Introductionmentioning

confidence: 99%

“…In Refs. [4,5], we argued that the HfO 2 /HfSi x O y stack layer allows us to maintain the excellent interfacial property due to the presence of the amorphous HfSi x O y thin film, while the effective dielectric constant can be further increased by forming the HfO 2 layer on HfSi x O y . Based on these phenomena, we recently demonstrated that multilayered high-k gate oxide (HfSi x O y /HfO 2 /IL/ZrO 2 /IL/HfO 2 ) with excellent electrical properties is formed by the simple oxidation of Hf/Zr/Hf films deposited directly on the Si substrate [6].…”

Section: Introductionmentioning

confidence: 99%

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