Search query: Thin films by chemical vapour deposition

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abstract: The explosive growth in the semiconductor industry has caused a rapid evolution of thin film materials that lend themselves to the fabrication of state of the art semiconductor devices. Early in the 1960s an old research technique named chemical vapour phase deposition (CVD) which has several unique advantages, developed into the most widely used technique for thin film preparation in electronics technology. In the last 25 years, tremendous advances have been made in the science and technology of thin films prepared by means of CVD. This book presents in a single volume, an up to date overview of the important field of CVD processes which has never been completely reviewed previously. Contents: Part I. 1. Evolution of CVD Films. Introductory remarks. Short history of CVD thin films. II. Fundamentals. 2. Techniques of Preparing Thin Films. Electrolytic deposition techniques. Vacuum deposition techniques. Plasma deposition techniques. Liquid phase deposition techniques. Solid phase deposition techniques. Chemical vapour conversion of substrate. Chemical vapour deposition. Comparison between CVD and other thin film deposition techniques. 3. Chemical Processes Used in CVD.
author_names: Constantin Morosanu
title: Thin films by chemical vapour deposition
year: 1990

abstract: Air stable caesium tin iodide double perovskite (Cs2SnI6) thin films have been fabricated via aerosol assisted chemical vapour deposition (AACVD) We compare the properties of the double perovskite films made using AACVD with those made by the widely used spin coating method. Films with purer crystalline phase (less CsI impurity) and far better stability in ambient air can be obtained by AACVD compared with spin coating. The AACVD grown Cs2SnI6 films retain high phase purity for at least ~100 days aging in air with negligible CsI impurities detected over this time, as determined by X ray diffraction. The films exhibit an optical band gap energy (Eg) of ca. 1.3 eV and a homogeneous morphology with the expected nominal stoichiometry within error, as probed by energy dispersive X ray spectroscopy. Overall, the characteristics of the Cs2SnI6 films are highly process dependent, e.g. they are influenced by the presence of hydroiodic acid (HI) in the precursor solution. Without HI addition, an iodine deficient film with more CsI is produced, which also exhibits a larger Eg of ca. 1.6 eV. In addition to bulk properties, we utilise X ray photoelectron spectroscopy (XPS) to scrutinise the surface characteristics in detail. We find excess Sn and I located at the surfaces. This can be attributed to the presence of SnI4 from the deposition precursor vapour. Furthermore, following aging in air, an increase in CsI impurity for the AACVD +HI) grown film is observed, along with a reduction in SnI4 at the surfaces. Near ambient pressure XPS (NAP XPS) is used to examine the surface stability of AACVD +HI) grown films on exposure to O2 and H2O. No enhancement in the amount of CsI impurity is observed after both H2O vapour (9 mbar) and O2 (5 mbar) exposure. Nevertheless, the concentrations of tin and iodine change after exposure, suggesting that SnI4 protects Cs2SnI6 from degradation. This passivation effect of SnI4 on Cs2SnI6 surfaces is proposed to explain the additional stability of Cs2SnI6 fabricated via AACVD.
author_names: Jack Chun-Ren Ke

David J Lewis

Alex S Walton

Ben F Spencer

Paul O'Brien

Andrew G Thomas

Wendy R Flavell
title: Ambient air stable inorganic Cs2SnI6 double perovskite thin films via aerosol assisted chemical vapour deposition
year: 2018

abstract: Epitaxial e gallium oxide (Ga2O3) thin films incorporated with In were successfully grown by mist chemical vapour deposition (CVD) on c plane sapphire substrates for bandgap tuning. In was successfully incorporated into epitaxial e (InxGa1 x)2O3 films at an In composition of x 0.2 without inducing phase separation. Phase separation originated from the (400) bixbyite structure of (InxGa1 x)2O3 when x 0.2. The solubility limit of In incorporated into e Ga2O3 on sapphire substrates via mist CVD was therefore x 0.2. Transmission electron microscopy measurements revealed that e (InxGa1 x)2O3 consisted of polycrystalline phases observed in the interface of the sapphire substrate and e phases located above the polycrystalline phase. The pole figure of e (InxGa1 x)2O3 thin films revealed that the epitaxial relationship between the e (InxGa1 x)2O3 thin film and the a Al2O3 substrate is (001) e (InxGa1 x)2O3 [130](0001) a Al2O3 [11 20] The optical bandgap of the e (InxGa1 x)2O3 thin films was tuned from 4.5 to 5.0 eV without inducing phase separation.
author_names: Hiroyuki Nishinaka

Nobutaka Miyauchi

Daisuke Tahara

Shota Morimoto

Masahiro Yoshimoto
title: Incorporation of indium into e gallium oxide epitaxial thin films grown via mist chemical vapour deposition for bandgap engineering
year: 2018

abstract: Integrating metal organic frameworks (MOFs) in microelectronics has disruptive potential because of the unique properties of these microporous crystalline materials. Suitable film deposition methods are crucial to leverage MOFs in this field. Conventional solvent based procedures, typically adapted from powder preparation routes, are incompatible with nanofabrication because of corrosion and contamination risks. We demonstrate a chemical vapour deposition process (MOF CVD) that enables high quality films of ZIF 8, a prototypical MOF material, with a uniform and controlled thickness, even on high aspect ratio features. Furthermore, we demonstrate how MOF CVD enables previously inaccessible routes such as lift off patterning and depositing MOF films on fragile features. The compatibility of MOF CVD with existing infrastructure, both in research and production facilities, will greatly facilitate MOF integration in microelectronics. MOF CVD is the first vapour phase deposition method for any type of microporous crystalline network solid and marks a milestone in processing such materials.
author_names: Ivo Stassen

Mark J Styles

Gianluca Grenci

Hans Van Gorp

Willem Vanderlinden

Steven De Feyter

Paolo Falcaro

Dirk De Vos

Philippe M Vereecken

Rob Ameloot
title: Chemical vapour deposition of zeolitic imidazolate framework thin films.
venue: Nature materials
year: 2016

abstract: Methyl ammonium lead iodide is the archetypal perovskite solar cell material. Phase pure, compositionally uniform methyl ammonium lead iodide thin films on large glass substrates were deposited using ambient pressure aerosol assisted chemical vapour deposition. This opens up a route to efficient scale up of hybrid perovskite film growth towards industrial deployment.
author_names: Davinder Singh Bhachu

David O Scanlon

E J Saban

Hugo Bronstein

Ivan P Parkin

Claire J Carmalt

Robert G Palgrave
title: Scalable route to CH3NH3PbI3 perovskite thin films by aerosol assisted chemical vapour deposition
year: 2015

abstract: Transparent conducting oxides have widespread application in modern society but there is a need to move away from the current 'industry champion' tin doped indium oxide (In2O3:Sn) due to high costs. Antimony doped tin(IV) oxide (ATO) is an excellent candidate but is limited by its opto electrical properties. Here, we present a novel and scalable synthetic route to ATO thin films that shows excellent electrical properties. Resistivity measurements showed that at 4 at% doping the lowest value of 4.7 x 10 4 O cm was achieved primarily due to a high charge carrier density of 1.2 x 1021 cm 3. Further doping induced an increase in resistivity due to a decrease in both the carrier density and mobility. Ab initio hybrid density functional theory (DFT) calculations show the thermodynamic basis for the tail off of performance beyond a certain doping level, and the appearance of Sb(III) within the doped thin films.
author_names: Sapna D Ponja

Benjamin A D Williamson

Sanjayan Sathasivam

David O Scanlon

Ivan P Parkin

Claire J Carmalt
title: Enhanced electrical properties of antimony doped tin oxide thin films deposited via aerosol assisted chemical vapour deposition
year: 2018

abstract: Abstract We present electrical and optical properties of CuCrO2 thin films deposited by chemical vapour deposition, as well as the influence of depositions' parameters on these properties. Oxygen partial pressure and precursor's concentrations have the greatest influence on optical and electrical properties of the films. Values of conductivities ranging from 10 4 to 10 S/cm were obtained using different deposition conditions. The conductivity is thermally activated with an activation energy ranging from 57 to 283 meV. Thermoelectric measurements confirm the p type conduction, and demonstrate high carrier concentration typical for a degenerate semiconductor. The as deposited films show a medium degree of crystallinity, a maximum optical transmission up to 80% in the visible range with a corresponding band gap around 3.2 eV.
author_names: Petru Lunca Popa

Jonathan Crepelliere

Renaud Leturcq

Damien Lenoble
title: Electrical and optical properties of Cu Cr O thin films fabricated by chemical vapour deposition
year: 2016

abstract: This work describes the first Aerosol Assisted Chemical Vapour Deposition (AACVD) synthesis of photocatalytic titanium dioxide thin films embedded with synthetic hydroxyapatite, [Ca10(PO4)(OH)2] nanoparticles. The hydroxyapatite nanoparticles were prepared using a low temperature continuous hydrothermal flow synthesis method; analysis of the hydroxyapatite powder showed that it was phase pure and that the as prepared material was made up of nano needles. The nanoparticles were then embedded into TiO2 coatings using the AACVD technique by suspending them in a solution of the titania precursor (titanium tetra isopropoxide) Results showed that the hydroxyapatite, although present in very low concentrations in the coatings (not detectable by XRD or Raman spectroscopy) heavily affected their morphology, depending on their concentration in the precursor solution. Tests of the photocatalytic activity of the composite films showed that the inclusion of the hydroxyapatite led to an increase in methylene blue photodegradation (up to 50% higher) and that the materials were photostable. This study shows that TiO2 coatings embedded with hydroxyapatite nanoparticles have potential as highly efficient photocatalysts.
author_names: Clara Piccirillo

C J Denis

Robert C Pullar

Russell Binions

Ivan P Parkin

Jawwad A Darr

Paula M L Castro
title: Aerosol assisted chemical vapour deposition of hydroxyapatite embedded titanium dioxide composite thin films
year: 2017

abstract: Diethyldithiocarbamato metal complexes of the general formula [M(S2CN(Et)2)n] (M Fe(III) Co(III) Ni(II) Cu(II) Zn(II) and n 2, 3) have been synthesized and used as precursors for the deposition of iron pyrite (FeS2) and transition metal doped iron pyrite (MxFe1 xS2) thin films on glass and indium tin oxide (ITO) coated glass substrates by aerosol assisted chemical vapour deposition (AACVD) Thermogravimetric analysis (TGA) confirmed that all the five complexes decompose into their corresponding metal sulfides. The iron complex [Fe(S2CNEt2)3] (1) deposited pure cubic pyrite (FeS2) films with granular crystallites at 350 degC, whereas at 450 degC pyrite and marcasite were deposited. MxFe1 xS2 (where M Co, Ni, Cu, or Zn) films were deposited by varying the relative concentration of complexes [Fe(S2CNEt2)3] (1) and [Co(S2CNEt2)3] (2) [Ni(S2CNEt2)2] (3) [Cu(S2CNEt2)2] (4) and [Zn(S2CNEt2)2] (5) at 350 degC. The formation of a solid solution was confirmed by powder X ray diffraction (p XRD) The surface morphology of the films was studied by scanning electron microscopy (SEM) whilst the height profiles of the films were revealed by atomic force microscopy (AFM) The elemental compositions of the films were confirmed by energy dispersive X ray (EDX) spectroscopy. To the best of our knowledge, these complexes are the first in their class to be used as single source precursors to deposit MxFe1 xS2 thin films.
author_names: Sadia Khalid

Ejaz Ahmed

Mohammad Azad Malik

David J Lewis

Shahzad Abu Bakar

Yaqoob Khan

Paul O'Brien
title: Synthesis of pyrite thin films and transition metal doped pyrite thin films by aerosol assisted chemical vapour deposition+
year: 2015

abstract: This work discusses an application of titanium oxide (TiOx) thin films deposited using physical (reactive magnetron sputtering, RMS) and chemical (atomic layer deposition, ALD) vapour deposition methods as a functional coating for label free optical biosensors. The films were applied as a coating for two types of sensors based on the localised surface plasmon resonance (LSPR) of gold nanoparticles deposited on a glass plate and on a long period grating (LPG) induced in an optical fibre. Optical and structural properties of the TiOx thin films were investigated and discussed. It has been found that deposition method has a significant influence on optical properties and composition of the films, but negligible impact on TiOx surface silanization effectiveness. A higher content of oxygen with lower Ti content in the ALD films leads to the formation of layers with higher refractive index and slightly higher extinction coefficient than for the RMS TiOx. Moreover, application of the TiOx film independently on deposition method enables not only for tuning of the spectral response of the investigated biosensors, but also in case of LSPR for enhancing the ability for biofunctionalization, i.e. TiOx film mechanically protects the nanoparticles and induces change in the biofunctionalization procedure to the one typical for oxides. TiOx coated LSPR and LPG sensors with refractive index sensitivity of close to 30 and 3400nm/RIU, respectively, were investigated. The ability for molecular recognition was evaluated with the well known complex formation between avidin and biotin as a model system. The shift in resonance wavelength reached 3 and 13.2nm in case of LSPR and LPG sensors, respectively. Any modification in TiOx properties resulting from the biofunctionalization process can be also clearly detected.
author_names: Magdalena Dominik

Adam Lesniewski

Marta Janczuk

Joanna Niedziolka-Jonsson

Marcin Holdynski

Lukasz Wachnicki

Marek Godlewski

Wojtek J Bock

Mateusz Smietana
title: Titanium oxide thin films obtained with physical and chemical vapour deposition methods for optical biosensing purposes.
venue: Biosensors bioelectronics
year: 2017