In-Situ Studies of Interfacial Bonding of High-k Dielectrics for CMOS Beyond 22nm

Wallace, Robert M.

doi:10.1149/1.2981608

Cited by 109 publications

(72 citation statements)

References 34 publications

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“…An in-situ study of the UV-Ozone exposure of ReS 2 was performed and chemical state changes were monitored by XPS. The UV photons from a low-pressure mercury lamp were used to produce ozone in a chamber (base pressure of ~10 −9 mbar) which was filled with O 2 to a pressure of 900 mbar [61]. Then, the sample was transferred in-situ to the ALD chamber for Al 2 O 3 deposition with TMA and H 2 O.…”

Section: Resultsmentioning

confidence: 99%

High-κ Dielectric on ReS2: In-Situ Thermal Versus Plasma-Enhanced Atomic Layer Deposition of Al2O3

et al. 2019

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We report an excellent growth behavior of a high-κ dielectric on ReS2, a two-dimensional (2D) transition metal dichalcogenide (TMD). The atomic layer deposition (ALD) of an Al2O3 thin film on the UV-Ozone pretreated surface of ReS2 yields a pinhole free and conformal growth. In-situ half-cycle X-ray photoelectron spectroscopy (XPS) was used to monitor the interfacial chemistry and ex-situ atomic force microscopy (AFM) was used to evaluate the surface morphology. A significant enhancement in the uniformity of the Al2O3 thin film was deposited via plasma-enhanced atomic layer deposition (PEALD), while pinhole free Al2O3 was achieved using a UV-Ozone pretreatment. The ReS2 substrate stays intact during all different experiments and processes without any formation of the Re oxide. This work demonstrates that a combination of the ALD process and the formation of weak S–O bonds presents an effective route for a uniform and conformal high-κ dielectric for advanced devices based on 2D materials.

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Section: Resultsmentioning

confidence: 99%

High-κ Dielectric on ReS2: In-Situ Thermal Versus Plasma-Enhanced Atomic Layer Deposition of Al2O3

et al. 2019

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“…X-ray Photoelectron Spectroscopy: XPS scans were carried out in an Ultra High Vacuum (UHV) cluster tool using an Omicron EA125 hemispherical 7 channels analyzer with a monochromatic Al Kα source (hν= 1486.7 eV). 45 XPS peaks were deconvoluted and analyzed using Aanalyzer software. 46 Quantitative analysis of the elemental concentration of the samples is acquired based on integrated photoelectron intensity and sensitivity factor for a given core level.…”

Section: -Probe and 4-probementioning

confidence: 99%

Atomically Controlled Tunable Doping in High‐Performance WSe₂ Devices

Pang

Hung

Khosravi

et al. 2020

Adv Elect Materials

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Two-dimensional transitional metal dichalcogenide (TMD) field-effect transistors (FETs) are promising candidates for future electronic applications, owing to their excellent transport properties and potential for ultimate device scaling. However, it is widely acknowledged that substantial contact resistance associated with the contact-TMD interface has impeded device performance to a large extent. It has been discovered that O2 plasma treatment can convert WSe2 into WO3-x and substantially improve contact resistances of p-type WSe2 devices by strong doping induced thinner depletion width. In this paper, we carefully study the temperature dependence of this conversion, demonstrating an oxidation process with a precise monolayer control at room temperature and multilayer conversion at elevated temperatures. Furthermore, the lateral oxidation of WSe2 under the contact revealed by HR-STEM leads to potential unpinning of the metal Fermi level and Schottky barrier lowering, resulting in lower contact resistances. The p-doping effect is attributed to the high electron affinity of the formed WO3-x layer on top of the remaining WSe2 channel, and the doping level is found to be 2 dependent on the WO3-x thickness that is controlled by the temperature. Comprehensive materials and electrical characterizations are presented, with a low contact resistance of ~528  m and record high on-state current of 320 A/m at -1V bias being reported.

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“…17 The MBE samples were then removed from the growth chamber for the ex situ nitrogen doping experiments. 18 in less than 10 min. Samples were heated to 300 • C under UHV and held at this temperature for 2 h (base pressure ∼ 10 9 mbar) to remove physisorbed species induced by air exposure following exfoliation.…”

mentioning

confidence: 91%

“…To study the surface chemistry after each treatment, the samples were transferred through a UHV transfer tube to an analysis chamber with a base pressure of ∼10 10 mbar equipped with X-ray photoelectron spectroscopy (XPS) described elsewhere. 18 The software AAnalyzer was used for XPS peak analysis. Active Shirley background and Voigt line shape was employed for peak fitting.…”

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confidence: 99%

Covalent nitrogen doping in molecular beam epitaxy-grown and bulk WSe2

et al. 2018

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Covalent p-type doping of WSe2 thin films grown by molecular beam epitaxy and WSe2 exfoliated from bulk crystals is achieved via remote nitrogen plasma exposure. X-ray photoelectron and Raman spectroscopies indicate covalently bonded nitrogen in the WSe2 lattice as well as tunable nitrogen concentration with N2 plasma exposure time. Furthermore, nitrogen incorporation induces compressive strain on the WSe2 lattice after N2 plasma exposure. Finally, atomic force microscopy and scanning tunneling microscopy reveal that N2 plasma treatment needs to be carefully tuned to avoid any unwanted strain or surface damage.

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In-Situ Studies of Interfacial Bonding of High-k Dielectrics for CMOS Beyond 22nm

Cited by 109 publications

References 34 publications

High-κ Dielectric on ReS2: In-Situ Thermal Versus Plasma-Enhanced Atomic Layer Deposition of Al2O3

High-κ Dielectric on ReS2: In-Situ Thermal Versus Plasma-Enhanced Atomic Layer Deposition of Al2O3

Atomically Controlled Tunable Doping in High‐Performance WSe₂ Devices

Covalent nitrogen doping in molecular beam epitaxy-grown and bulk WSe2

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In-Situ Studies of Interfacial Bonding of High-k Dielectrics for CMOS Beyond 22nm

Cited by 109 publications

References 34 publications

High-κ Dielectric on ReS2: In-Situ Thermal Versus Plasma-Enhanced Atomic Layer Deposition of Al2O3

High-κ Dielectric on ReS2: In-Situ Thermal Versus Plasma-Enhanced Atomic Layer Deposition of Al2O3

Atomically Controlled Tunable Doping in High‐Performance WSe2 Devices

Covalent nitrogen doping in molecular beam epitaxy-grown and bulk WSe2

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Atomically Controlled Tunable Doping in High‐Performance WSe₂ Devices