scholarly journals Atomic Layer Deposition of HfO2 Thin Films on Si and GaAs Substrates

2008 ◽  
Vol 1073 ◽  
Author(s):  
Justin C Hackley ◽  
J. Derek Demaree ◽  
Theodosia Gougousi
Keyword(s):  
Thin Films ◽  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Rutherford Backscattering Spectrometry ◽  
Surface Oxidation ◽  
Atomic Layer ◽  
Native Oxide ◽  
Native Oxides ◽  
Gaas Substrates ◽  
Layer Deposition

ABSTRACTThe atomic layer deposition of HfO2 thin films is studied on Si(100) and GaAs(100) surfaces. The films are grown using tetrakis(dimethylamido)hafnium (TDMAH) and H2O precursors at a deposition temperature of 275°C. The Si surfaces used include a H-terminated surface and an OH-rich chemical oxide. GaAs substrates are subjected to two different pre-deposition treatments involving an HF and a NH4OH wet chemical etch that has been shown to remove most of the Ga and As native oxides. Spectroscopic ellipsometry (SE) confirms linear growth rates of 1.05±0.05 Å/cycle for all surfaces. Rutherford backscattering spectrometry (RBS) shows that steady-state growth of 2.6×1014 Hf/cm2/cycle is reached after 10 ALD cycles for the HF-etched GaAs surface. X-ray photoelectron spectroscopy (XPS) indicates the presence of native oxides on both GaAs starting surfaces after 10 cycles due to postdeposition surface oxidation. However, the presence of the native oxide is not detected for thicker 15 and 20 cycle samples indicating passivation of the surface and suppression of the interfacial layer formation.

scholarly journals Nucleation Studies of HfO2 Thin Films Produced by Atomic Layer Deposition

2007 ◽  
Vol 996 ◽  
Author(s):  
Justin C. Hackley ◽  
J. Derek Demaree ◽  
Theodosia Gougousi
Keyword(s):  
Thin Films ◽  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Flow Reactor ◽  
Atomic Layer ◽  
Sample Surface ◽  
Interfacial Region ◽  
Initial Growth ◽  
Layer Deposition ◽  
Similar Growth

AbstractA hot wall Atomic Layer Deposition (ALD) flow reactor equipped with a Quartz Crystal Microbalance (QCM) has been used for the deposition of HfO2 thin films with tetrakis (dimethylamino) hafnium (TDMAH) and H2O as precursors. HfO2 films were deposited on H-terminated Si and SC1 chemical oxide starting surfaces. Spectroscopic ellipsometry (SE) and QCM measurements confirm linear growth of the films at a substrate temperature of 275°C. FTIR spectra indicate the films are amorphous as-deposited. Two distinct growth regimes are observed: from 1-50 cycles, both surfaces display similar growth rates of about 1.0Å/cycle; from 50-200 cycles, HfO2 growth is decreased by about 15% to ~0.87Å/cycle on both surfaces. Nucleation and initial growth behavior of the films on Si-H were examined using X-ray photoelectron spectroscopy (XPS). Angle-resolved XPS, at take-off angles of θ=0, 15, 30, 45 and 60° measured from the normal to the sample surface, is used to probe the interfacial region of thin films (4, 7, 10, 15 and 25 cycles) on H-terminated samples. Initially, an interfacial layer comprised of a SiOx/HfSiOx mixture is grown between 1-10 ALD cycles. We observe that the Si/HfO2 interface is unstable, and oxidation continues up to the 25th ALD cycle, reaching a thickness of ~18Å.

High-k ZrO2 dielectric thin films on GaAs semiconductor with reduced regrowth of native oxides by atomic layer deposition

2013 ◽  
Vol 583 ◽  
pp. 74-79 ◽  
Author(s):  
R.B. Konda ◽  
C. White ◽  
J. Smak ◽  
R. Mundle ◽  
M. Bahoura ◽  
...  
Keyword(s):  
Thin Films ◽  
Atomic Layer Deposition ◽  
Atomic Layer ◽  
Dielectric Thin Films ◽  
Native Oxides ◽  
Layer Deposition ◽  
High K

scholarly journals Atomic Layer Deposition of Metal Oxide Films on GaAs (100) surfaces

2009 ◽  
Vol 1155 ◽  
Author(s):  
Theodosia Gougousi ◽  
John W. Lacis ◽  
Justin C Hackley ◽  
John Demaree
Keyword(s):  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Film Growth ◽  
Atomic Layer ◽  
Metal Oxide Films ◽  
Rutherford Back Scattering ◽  
Native Oxides ◽  
Layer Deposition ◽  
Back Scattering ◽  
Film Substrate

AbstractAtomic Layer Deposition is used to deposit HfO2 and TiO2 films on GaAs (100) native oxides and etched surfaces. For the deposition of HfO2 films two different but similar ALD chemistries are used: i) tetrakis dimethyl amido hafnium (TDMAHf) and H2O at 275°C and ii) tetrakis ethylmethyl amido hafnium (TEMAHf) and H2O at 250°C. TiO2 films are deposited from tetrakis dimethyl amido titanium (TDMATi) and H2O at 200°C. Rutherford Back Scattering shows linear film growth for all processes. The film/substrate interface is examined using x-ray Photoelectron Spectroscopy and confirms the presence of an “interfacial cleaning” mechanism.

scholarly journals Growth of lithium hydride thin films from solutions: Towards solution atomic layer deposition of lithiated films

2019 ◽  
Vol 10 ◽  
pp. 1443-1451
Author(s):  
Ivan Kundrata ◽  
Karol Fröhlich ◽  
Lubomír Vančo ◽  
Matej Mičušík ◽  
Julien Bachmann
Keyword(s):  
Thin Films ◽  
Atomic Layer Deposition ◽  
Surface Area ◽  
Photoelectron Spectroscopy ◽  
Vapour Deposition ◽  
Chemical Vapour ◽  
Atomic Layer ◽  
Lithium Hydride ◽  
X Ray ◽  
Layer Deposition

Lithiated thin films are necessary for the fabrication of novel solid-state batteries, including the electrodes and solid electrolytes. Physical vapour deposition and chemical vapour deposition can be used to deposit lithiated films. However, the issue of conformality on non-planar substrates with large surface area makes them impractical for nanobatteries the capacity of which scales with surface area. Atomic layer deposition (ALD) avoids these issues and is able to deposit conformal films on 3D substrates. However, ALD is limited in the range of chemical reactions, due to the required volatility of the precursors. Moreover, relatively high temperatures are necessary (above 100 °C), which can be detrimental to electrode layers and substrates, for example to silicon into which the lithium can easily diffuse. In addition, several highly reactive precursors, such as Grignard reagents or n-butyllithium (BuLi) are only usable in solution. In theory, it is possible to use BuLi and water in solution to produce thin films of LiH. This theoretical reaction is self-saturating and, therefore, follows the principles of solution atomic layer deposition (sALD). Therefore, in this work the sALD technique and principles have been employed to experimentally prove the possibility of LiH deposition. The formation of homogeneous air-sensitive thin films, characterized by using ellipsometry, grazing incidence X-ray diffraction (GIXRD), in situ quartz crystal microbalance, and scanning electron microscopy, was observed. Lithium hydride diffraction peaks have been observed in as-deposited films by GIXRD. X-ray photoelectron spectroscopy and Auger spectroscopy analysis show the chemical identity of the decomposing air-sensitive films. Despite the air sensitivity of BuLi and LiH, making many standard measurements difficult, this work establishes the use of sALD to deposit LiH, a material inaccessible to conventional ALD, from precursors and at temperatures not suitable for conventional ALD.

Optimization of Copper Schottky Contacts on Nanocrystalline ZnO thin films by Atomic Layer Deposition

MRS Advances ◽  
2016 ◽  
Vol 1 (50) ◽  
pp. 3421-3427
Author(s):  
Mei Shen ◽  
Triratna P. Muneshwar ◽  
Ken Cadien ◽  
Ying Y. Tsui ◽  
Doug Barlage
Keyword(s):  
Thin Films ◽  
Low Temperature ◽  
Atomic Layer Deposition ◽  
Thermionic Emission ◽  
Surface Oxidation ◽  
Atomic Layer ◽  
Zno Thin Films ◽  
Maximum Temperature ◽  
Thermal Reliability ◽  
Layer Deposition

ABSTRACTContact metallization is an essential obstacle for utilizing low temperature achievable polycrystalline ZnO in any discrete devices and integrated circuits. To develop ZnO based semiconductor devices with advanced feature of flexibility, transparency and compatibility with low temperature processing, rectifying junctions must be fully developed. In this work, nanoscale polycrystalline ZnO thin films are fabricated with via low temperature (<200 °C) by atomic layer deposition (ALD). A vertical structure of bottom Schottky metallized diode is developed with copper (Cu) sputtered in room temperature. A control of Cu surface oxidation is realized with an in-situ remote plasma treatment. The results indicate that preparation of the copper surface substantially affects the electrical behavior of the diode. Thermal reliability of Cu metallized Schottky diode is subsequently carried out by annealing up to a maximum temperature of 300 °C before it breaks. This work considers the current transport mechanism evolved deviating current vs voltage (I-V) characteristics from conventional thermionic emission theory.

Characteristics of hafnium oxide grown on silicon by atomic-layer deposition using tetrakis(ethylmethylamino)hafnium and water vapor as precursors

2007 ◽  
Vol 22 (7) ◽  
pp. 1899-1906 ◽  
Author(s):  
Yan-Kai Chiou ◽  
Che-Hao Chang ◽  
Tai-Bor Wu
Keyword(s):  
Thin Films ◽  
Atomic Layer Deposition ◽  
Charge Density ◽  
Photoelectron Spectroscopy ◽  
Hafnium Oxide ◽  
Atomic Layer ◽  
Oxide Semiconductor ◽  
Electrical Performance ◽  
Breakdown Field ◽  
Layer Deposition

The growth of HfO2 thin films on a HF-dipped p-Si(100) substrate at 200 °C by atomic-layer deposition (ALD) using Hf[N(C2H5)(CH3)]4 and H2O vapor as precursors is demonstrated. Uniform HfO2 thin films are obtained on a 4-in. silicon wafer, and the energy-band gap and band offset are determined by x-ray photoelectron spectroscopy analysis. The as-deposited HfO2 thin film is amorphous and able to crystallize at 500 ∼ 600 °C with only the monoclinic phase. As for the electrical performance of Au–Ti–HfO2–Si metal oxide semiconductor capacitors, a dielectric constant of ∼17.8 and an equivalent oxide thickness value of ∼1.39 nm are obtained from the 40-cycle ALD film after annealing at 500 °C. In addition, the breakdown field is in the range of 5 ∼ 5.5 MV/cm, and the fixed charge density is on the order of 1012 cm−2, depending on the annealing temperatures. The interface quality of HfO2 thin films on silicon is satisfactory with an interface-trap charge density of ∼3.7 × 1011 cm−2 eV−1.

scholarly journals Plasma Enhanced Atomic Layer Deposition of Tantalum (V) Oxide

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1206
Author(s):  
Pavel Fedorov ◽  
Denis Nazarov ◽  
Oleg Medvedev ◽  
Yury Koshtyal ◽  
Aleksander Rumyantsev ◽  
...  
Keyword(s):  
Thin Films ◽  
Atomic Layer Deposition ◽  
Photoelectron Spectroscopy ◽  
Protective Coatings ◽  
Lithium Ion ◽  
Atomic Layer ◽  
Evaporator Temperature ◽  
Current Increase ◽  
X Ray ◽  
Layer Deposition

The tantalum oxide thin films are promising materials for various applications: as coatings in optical devices, as dielectric layers for micro and nanoelectronics, and for thin-films solid-state lithium-ion batteries (SSLIBs). This article is dedicated to the Ta-O thin-film system synthesis by the atomic layer deposition (ALD) which allows to deposit high quality films and coatings with excellent uniformity and conformality. Tantalum (V) ethoxide (Ta(OEt)5) and remote oxygen plasma were used as tantalum-containing reagent and oxidizing co-reagent, respectively. The influence of deposition parameters (reactor and evaporator temperature, pulse and purge times) on the growth rate were studied. The thickness of the films were measured by spectroscopic ellipsometry, scanning electron microscopy and X-ray reflectometry. The temperature range of the ALD window was 250–300 °C, the growth per cycle was about 0.05 nm/cycle. Different morphology of films deposited on silicon and stainless steel was found. According to the X-ray diffraction data, the as-prepared films were amorphous. But the heat treatment study shows crystallization at 800 °C with the formation of the polycrystalline Ta2O5 phase with a rhombic structural type (Pmm2). The results of the X-ray reflectometry show the Ta-O films’ density is 7.98 g/cm3, which is close to the density of crystalline Ta2O5 of the rhombic structure (8.18 g/cm3). The obtained thin films have a low roughness and high uniformity. The chemical composition of the surface and bulk of Ta-O coatings was studied by X-ray photoelectron spectroscopy and energy-dispersive X-ray spectroscopy. Surface of the films contain Ta2O5 and some carbon contamination, but the bulk of the films does not contain carbon and any precursor residues. Cyclic voltammetry (CVA) showed that there is no current increase for tantalum (V) oxide in a potential window of 3–4.2 V and has prospects of use as protective coatings for cathode materials of SSLIBs.

Atomic layer deposition of tungsten disulphide solid lubricant thin films

2004 ◽  
Vol 19 (12) ◽  
pp. 3443-3446 ◽  
Author(s):  
T.W. Scharf ◽  
S.V. Prasad ◽  
T.M. Mayer ◽  
R.S. Goeke ◽  
M.T. Dugger
Keyword(s):  
Thin Films ◽  
Atomic Layer Deposition ◽  
Solid Lubricant ◽  
Atomic Layer ◽  
Nucleation And Growth ◽  
Silicon Surfaces ◽  
Native Oxide ◽  
Tungsten Disulphide ◽  
Layer Deposition

The synthesis and characterization of crystalline tungsten disulphide (WS2) solid lubricant thin films grown by atomic layer deposition (ALD) using WF6 and H2S gas precursors was studied. A new catalytic route was established to promote nucleation and growth of WS2 films on silicon surfaces with native oxide. Scanning electron microscopy with energy dispersive spectroscopy and Raman spectroscopy were used to determine the film morphology, composition, and crystallinity. The films exhibited solid lubricating behavior with a steady-state friction coefficient of 0.04 in a dry nitrogen environment.

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