Topic
Atomic layer deposition
About: Atomic layer deposition is a research topic. Over the lifetime, 19821 publications have been published within this topic receiving 477332 citations. The topic is also known as: ALD.
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TL;DR: Al-doped ZnO (AZO) films of ∼100nm thickness with various Al doping were prepared at 150°C by atomic layer deposition on quartz substrates as mentioned in this paper.
Abstract: Al-doped ZnO (AZO) films of ∼100 nm thickness with various Al doping were prepared at 150 °C by atomic layer deposition on quartz substrates. At low Al doping, the films were strongly textured along the [100] direction, while at higher Al doping the films remained amorphous. Atomic force microscopy results showed that Al–O cycles when inserted in a ZnO film, corresponding to a few atomic percent Al, could remarkably reduce the surface roughness of the films. Hall measurements revealed a maximum mobility of 17.7 cm2/V s. Film resistivity reached a minima of 4.4×10−3 Ω cm whereas the carrier concentration reached a maxima of 1.7×1020 cm−3, at 3 at. % Al. The band gap of AZO films varied from 3.23 eV for undoped ZnO films to 3.73 eV for AZO films with 24.6 at. % Al. Optical transmittance over 80% was obtained in the visible region. The detrimental impact of increased Al resulting in decreased conductivity due to doping past 3.0 at. % is evident in the x-ray diffraction data, as an abrupt increase in the opti...
318 citations
TL;DR: In this paper, the authors have studied hafnium oxide and aluminum oxide grown on gallium arsenide by atomic layer deposition and showed that as-deposited films are continuous and predominantly amorphous.
Abstract: High-performance metal-oxide-semiconductor field effect transistors (MOSFETs) on III–V semiconductors have long proven elusive. High-permittivity (high-κ) gate dielectrics may enable their fabrication. We have studied hafnium oxide and aluminum oxide grown on gallium arsenide by atomic layer deposition. As-deposited films are continuous and predominantly amorphous. A native oxide remains intact underneath HfO2 during growth, while thinning occurs during Al2O3 deposition. Hydrofluoric acid etching prior to growth minimizes the final interlayer thickness. Thermal treatments at ∼600°C decompose arsenic oxides and remove interfacial oxygen. These observations explain the improved electrical quality and increased gate stack capacitance after thermal treatments.
317 citations
TL;DR: In this paper, the authors reported the observation of ferroelectric characteristics in undoped hafnium oxide thin films in a thickness range of 4-20nm, which were fabricated using atomic layer deposition and embedded into titanium nitride based metal-insulator-metal (MIM) capacitors for electrical evaluation.
Abstract: We report the observation of ferroelectric characteristics in undoped hafnium oxide thin films in a thickness range of 4–20 nm. The undoped films were fabricated using atomic layer deposition (ALD) and embedded into titanium nitride based metal-insulator-metal (MIM) capacitors for electrical evaluation. Structural as well as electrical evidence for the appearance of a ferroelectric phase in pure hafnium oxide was collected with respect to film thickness and thermal budget applied during titanium nitride electrode formation. Using grazing incidence X-Ray diffraction (GIXRD) analysis, we observed an enhanced suppression of the monoclinic phase fraction in favor of an orthorhombic, potentially, ferroelectric phase with decreasing thickness/grain size and for a titanium nitride electrode formation below crystallization temperature. The electrical presence of ferroelectricity was confirmed using polarization measurements. A remanent polarization Pr of up to 10 μC cm−2 as well as a read/write endurance of 1.6 ×...
315 citations
TL;DR: This work demonstrates the improvement of gas-sensing performance of large-area tungsten disulfide (WS2) nanosheets through surface functionalization using Ag nanowires (NWs) to improve 2D TMDC gas sensors.
Abstract: Semiconducting two-dimensional (2D) transition metal dichalcogenides (TMDCs) are promising gas-sensing materials due to their large surface-to-volume ratio. However, their poor gas-sensing performance resulting from the low response, incomplete recovery, and insufficient selectivity hinders the realization of high-performance 2D TMDC gas sensors. Here, we demonstrate the improvement of gas-sensing performance of large-area tungsten disulfide (WS2) nanosheets through surface functionalization using Ag nanowires (NWs). Large-area WS2 nanosheets were synthesized through atomic layer deposition of WO3 followed by sulfurization. The pristine WS2 gas sensors exhibited a significant response to acetone and NO2 but an incomplete recovery in the case of NO2 sensing. After AgNW functionalization, the WS2 gas sensor showed dramatically improved response (667%) and recovery upon NO2 exposure. Our results establish that the proposed method is a promising strategy to improve 2D TMDC gas sensors.
315 citations
Patent•
21 Apr 2004
TL;DR: In this paper, the precursors are comprised of at least one different chemical component, and such different components will form a mono-layer to produce a multi-component film.
Abstract: The present invention provides systems and methods for mixing precursors such that a mixture of precursors are present together in a chamber during a single pulse step in an atomic layer deposition (ALD) process to form a multi-component film. The precursors are comprised of at least one different chemical component, and such different components will form a mono-layer to produce a multi-component film. In a further aspect of the present invention, a dielectric film having a composition gradient is provided.
314 citations