Query: Atomic layer deposition of tin oxide films

Candidate papers:

abstract: Thin film solar cells made from earth abundant, non toxic materials are needed to replace the current technology that uses Cu(In,Ga)(S,Se)2 and CdTe, which contain scarce and toxic elements. One promising candidate absorber material is tin monosulfide (SnS) In this report, pure, stoichiometric, single phase SnS films were obtained by atomic layer deposition (ALD) using the reaction of bis(N,N' diisopropylacetamidinato)tin(II) [Sn(MeC(N iPr)2)2] and hydrogen sulfide (H2S) at low temperatures (100 to 200 degC) The direct optical band gap of SnS is around 1.3 eV and strong optical absorption (a 104 cm 1) is observed throughout the visible and near infrared spectral regions. The films are p type semiconductors with carrier concentration on the order of 1016 cm 3 and hole mobility 0.82 15.3 cm2V 1s 1 in the plane of the films. The electrical properties are anisotropic, with three times higher mobility in the direction through the film, compared to the in plane direction.
author_names: Prasert Sinsermsuksakul

Jaeyeong Heo

Wontae Noh

Adam S Hock

Roy G Gordon
title: Atomic Layer Deposition of Tin Monosulfide Thin Films
year: 2011

abstract: The authors present a new method for preparing thin films of SnO2 by atomic layer deposition (ALD) using alternating exposures to tetrakis(dimethylamino) tin and hydrogen peroxide. This method avoids problems of corrosion and agglomeration associated with the halogenated compound, SnCl4. Tin oxide films were successfully deposited on a variety of substrates using deposition temperatures of 50 300degC at an average growth rate of 1.2A/cycle. They use in situ quartz crystal microbalance and quadrupole mass spectrometry measurements to explore the mechanism for SnO2 ALD. Scanning electron microscopy of SnO2 films deposited on Si(100) show that the SnO2 films are smooth, conformal, and nearly featureless, while atomic force microscopy yields a surface roughness of only 0.84nm for a film with a thickness of 92nm. X ray diffraction reveals that the SnO2 films are amorphous. Films deposited on glass yielded a resistivity of ~0.3Ocm and an optical transmission of 94% for a film thickness of 140nm. X ray photoelectr.
author_names: Jeffrey W Elam

David A Baker

Alexander J Hryn

Alex B F Martinson

Michael J Pellin

Joseph T Hupp
title: Atomic layer deposition of tin oxide films using tetrakis(dimethylamino) tin
year: 2008

abstract: Atomic layer deposition (ALD) of tin oxide (SnOx) films was achieved using a newly synthesized tin precursor and hydrogen peroxide. We obtained highly pure, conductive SnOx films at temperatures as low as 50 degC, which was possible because of high chemical reactivity between the new Sn precursor and hydrogen peroxide. The growth per cycle is around 0.18 nm/cycle in the ALD window up to 150 degC, and decreased at higher temperatures. Self limited growth was demonstrated for both the Sn and O precursors. Thickness is linear in the number of cycles, with an induction period of not more than a few cycles. Rutherford backscattering spectroscopy (RBS) and X ray photoelectron spectroscopy (XPS) measurements showed that the composition ratio of O/Sn is ~2 and that the films do not contain any detectable carbon or nitrogen impurities. X ray and electron diffraction analyses identified crystallites of SnO2 with the rutile structure and average grain size 5 10 nm. The density of the films is 83% of the bulk rutile phas.
author_names: Jaeyeong Heo

Adam S Hock

Roy G Gordon
title: Low Temperature Atomic Layer Deposition of Tin Oxide
year: 2010

abstract: In this work we present a low cost and scalable technique, via ambient pressure chemical vapor deposition (CVD) on polycrystalline Ni films, to fabricate large area approximately cm2) films of single to few layer graphene and to transfer the films to nonspecific substrates. These films consist of regions of 1 to approximately 12 graphene layers. Single or bilayer regions can be up to 20 mum in lateral size. The films are continuous over the entire area and can be patterned lithographically or by prepatterning the underlying Ni film. The transparency, conductivity, and ambipolar transfer characteristics of the films suggest their potential as another materials candidate for electronics and opto electronic applications.
author_names: Alfonso Reina

Xiaoting Jia

John T Ho

Daniel Nezich

Hyungbin Son

Vladimir Bulovic

Mildred S Dresselhaus

Jing Kong
title: Large area, few layer graphene films on arbitrary substrates by chemical vapor deposition.
venue: Nano letters
year: 2009

abstract: The deposition of conformal coatings into porous silicon layers was successfully demonstrated. Tin oxide films were formed from SnCl 4 and H 2 O precursors by atomic layer epitaxy. The influence of the porous substrate structure on the deposition parameters was analyzed from the viewpoint of formation mechanism, growth rate, and layer composition. The SnO x covered porous substrates were characterized by means of Rutherford backscattering, secondary ion mass spectrometry, cross sectional transmission electron microscopy, and ellipsometry. The mesoporous structure of the Si substrate uniquely determines the gas phase diffusion and physisorption of the precursors. The processing parameters favoring chemisorption are more critical for porous silicon than those for a flat surface. Even a small decrease in the deposition temperature results in a considerable increase in the growth rate through gas phase reactions, and the process becomes chemical vapor deposition like. Conformal step coverage was obtained on extremely high (140 :1) aspect ratio pores if the deposition conditions were chosen such that chemisorption was the growth rate determining step in the process.
author_names: Csaba Ducso

Nguyen Quoc Khanh

Zsolt Endre Horvath

Istvan Barsony

Mikko Utriainen

Sari Lehto

Minna Nieminen

Lauri Niinisto
title: Deposition of tin oxide into porous silicon by atomic layer epitaxy
year: 1996

abstract: Atomic layer deposition (ALD) is a process for depositing highly uniform and conformal thin films by alternating exposures of a surface to vapours of two chemical reactants. ALD processes have been successfully demonstrated for many metal compounds, but for only very few pure metals. Here we demonstrate processes for the ALD of transition metals including copper, cobalt, iron and nickel. Homoleptic N,N' dialkylacetamidinato metal compounds and molecular hydrogen gas were used as the reactants. Their surface reactions were found to be complementary and self limiting, thus providing highly uniform thicknesses and conformal coating of long, narrow holes. We propose that these ALD layers grow by a hydrogenation mechanism that should also operate during the ALD of many other metals. The use of water vapour in place of hydrogen gas gives highly uniform, conformal films of metal oxides, including lanthanum oxide. These processes should permit the improved production of many devices for which the ALD process has previously not been applicable.
author_names: Booyong S Lim

Antti Rahtu

Roy G Gordon
title: Atomic layer deposition of transition metals
venue: Nature materials
year: 2003

abstract: films have been fabricated using many different technologies, including sputtering [1] chemical vapor deposition [2] spray pyrolysis [3] and atomic layer deposition (ALD) [4] [5] Amongst these ALD produces unique film properties compared with other methods. In particular dense films of high aspect ratio and fewer defects are achieved. ALD is also an ideal technology for the deposition of ultrathin films with high conformality and precise thickness control [6] ALD is a dense thin film growth technology using an alternating self controlled chemical process between the gas precursor and a solid surface in order to deposit materials in an atomic layer by layer fashion. This methodology can produce films with very precise control over film thickness and composition. This technology allows precise coatings to be applied on other surfaces of powder and porous materials. Plasma enhanced ALD (PEALD) is a promising technology for obtaining high quality metal oxide films at relatively low temperatures compared with commercial CVD. Interestingly, the comparative study of the growth of tin oxide films by ALD and chemical vapor deposition was reported [7] The films were of the tetragonal rutile type for both cases. Thin films grown by ALD were found to be close to being perfect single crystals, containing a low density of defects and were almost atomically smooth. The CVD films had a much rougher film morphology and exhibited both grain boundaries and twin formation. Tin oxide thin films have been fabricated previously by ALD using halogenated precursors, SnCl
author_names: Woon-Seop Choi
title: The Fabrication of Tin Oxide Films by Atomic Layer Deposition using Tetrakis(Ethylmethylamino) Tin Precursor
year: 2009

abstract: Titanium nitride (TiN) films were deposited by a plasma assisted atomic layer deposition (PA ALD) process, based on TiCl 4 precursor dosing and remote H 2 N 2 plasma exposure, at temperatures ranging from 100 to 400degC. The plasma, the PA ALD process, and the resulting TiN material properties were extensively investigated. The plasma was studied by optical emission spectroscopy and Langmuir probe, revealing an ion density of 10 9 cm 3 and an electron temperature of 3.5 eV just above the substrate. Under floating conditions there is thus a considerable ion flux towards the substrate per ALD cycle with a typical ion energy of 15 eV. TiN film growth was studied by in situ spectroscopic ellipsometry, revealing self limiting surface reactions for the complete temperature range. At 100degC the growth rate of 0.3 A/cycle was found to be significantly lower than the growth rate of 0.6 A/cycle at 400degC. The stoichiometry of the films varied with the plasma exposure time, while the Cl content was mostly affected by the deposition temperature (2.1 atom at 100degC to 0.07 atom at 400degC) Resistivities as low as 71 mO cm were obtained at a temperature of 400degC, while at 100degC a fair resistivity of 209 mO cm was reached. These results show that PA ALD with TiCl 4 and H 2 N 2 plasma is well suited for low temperature deposition of high quality TiN films.
author_names: Sbs Stephan Heil

E Erik Langereis

Fred Roozeboom

Van de Sanden

Wmm Erwin Kessels
title: Low Temperature Deposition of TiN by Plasma Assisted Atomic Layer Deposition
year: 2006

abstract: The authors deposited thin films of tin oxide on substrates of silicon and stainless steel by using atomic layer deposition (ALD) with tetraethyltin precursors. In this process, the authors used various coreactants such as water, oxygen, remote oxygen plasma, hydrogen peroxide, and ozone. The growth rates of films were studied as functions of the deposition temperature, the pulse times of the precursor and coreactant, and the number of ALD cycles, and the optimal growth conditions were determined. The film growth rates were found to be 0.025, 0.045, and 0.07 nm per cycle within the optimal growth conditions and ALD temperature windows for H2O2, O3, and O2 plasma, respectively. Using H2O or O2 did not prompt film growth. The films deposited using O3 and H2O2 had good continuity and low roughness, while the morphology of a coating prepared using oxygen plasma depended greatly on the deposition temperature. The films produced at temperatures below 300 degC were amorphous, irrespective of the coreactant used. X.
author_names: Denis V Nazarov

Maxim Yu Maximov

Pavel Alexandrovich Novikov

Anatoly A Popovich

Aleksey Silin

Vladimir M Smirnov

Natalia P Bobrysheva

Olga M Osmolovskaya

M G Osmolovsky

A M Rumyantsev
title: Atomic layer deposition of tin oxide using tetraethyltin to produce high capacity Li ion batteries
year: 2017

abstract: Silicon or glass substrates exposed to sequential pulses of tetraethyltin (TET) and ozone (O3) were coated with thin films of SnO2. Self limiting deposition was found using 8 s pulse times, and a uniform thickness per cycle (TPC) of 0.2 nm/cycle was observed in a small, yet reproducible, temperature window from 290 to 320 degC. The as deposited, stoichiometric SnO2 films were amorphous and transparent above 400 nm. Interspersing pulses of diethylzinc and O3 among the TET:O3 pulses resulted in deposition of zinc tin oxide films, where the fraction of tin, defined as [at. Sn/(at. Sn at. Zn) was controlled by the ratio of TET pulses, specifically nTET:(nTET nDEZ) where nTET and nDEZ are the number of precursor/O3 subcycles within each atomic layer deposition (ALD) supercycle. Based on film thickness and composition measurements, the TET pulse time required to reach saturation in the TPC of SnO2 on ZnO surfaces was increased to >30 s. Under these conditions, film stoichiometry as a function of the T.
author_names: Ellis J Warner

Forrest Johnson

Stephen A Campbell

Wayne L Gladfelter
title: Atomic layer deposition of tin oxide and zinc tin oxide using tetraethyltin and ozone
year: 2015