Sputter Epitaxy of (ZnO)x(InN)1-x films on Lattice-mismatched Sapphire Substrate

ABSTRACTWe have recently developed a novel semiconductor, (ZnO)x(InN)1-x (abbreviated to ZION). In this study, we have succeeded in direct epitaxial growth of ZION films on 19–21%-lattice-mismatched c-plane sapphire by radio-frequency (RF) magnetron sputtering. X-ray diffraction analysis showed that there is no epitaxial relationship between ZION films fabricated at room-temperature (RT) and the sapphire substrates, while the films fabricated at 450oC grow epitaxially on the sapphire substrates. From the analysis of time evolution of the surface morphology, the process for the epitaxial growth of ZION on sapphire is found to consist of three stages. They are (i) initial nucleation of ZION crystallites with crystal axis aligned to the sapphire substrate, (ii) island growth from the initially formed nuclei and subsequent nucleation (secondary nucleation) of ZION crystallites, and (iii) lateral growth of ZION islands originated from initially formed nuclei. On the other hand, non-epitaxial ZION films fabricated at RT just grow in 3D mode. From these results, we conclude that the substrate temperature is the key to control of nucleation and subsequent epitaxial growth of ZION films on the lattice-mismatched substrate.

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Growth and Evaluation of Magnetoelectric Cr2O3 Single Crystal Thin Films

MRS Proceedings ◽

10.1557/proc-1034-k10-67 ◽

2007 ◽

Vol 1034 ◽

Cited By ~ 1

Author(s):

Nobuyuki Iwata ◽

Takeshi Asada ◽

Shunpei Ootsuki ◽

Hiroshi Yamamoto

Keyword(s):

Thin Films ◽

Bragg Reflection ◽

Substrate Surface ◽

Rf Magnetron Sputtering ◽

High Energy ◽

X Ray Diffraction ◽

Epitaxial Relationship ◽

Sapphire Substrates ◽

Stacking Order ◽

Growth Difference

AbstractThe Cr2O3 thin films were grown on Al2O3(1102)(r-cut sapphire), Al2O3(1120)(a-cut sapphire), and Al2O3(0001)(c-cut sapphire) substrates to apply magnetoelectric oxides to oxides electronics. The Cr2O3 is a representative magnetoelectric material with antiferromagnetic insulator with the Néel temperature of 308 K. From the results of X-ray diffraction and the reflection high energy electron diffraction, epitaxial Cr2O3 thin films were obtained on all cut sapphire substrates using off-axis DC-RF magnetron sputtering method. The epitaxial relationship was Cr2O3[1120]//Al2O3[1120] and Cr2O3(1102)//Al2O3(1102) on r-cut, and Cr2O3[1100]//Al2O3[1100] and Cr2O3(1120)//Al2O3(1120) on a-cut, and Cr2O3[1120]//Al2O3[1120] and Cr2O3(0001)//Al2O3(0001) on c-cut. Optimized Cr2O3 film was obtained grown at 600°C on c-cut sapphire substrate. The surface roughness (Ra) of the film was 0.28 nm, and full width at half maximum of rocking curve for Cr2O3(0006) Bragg reflection was 0.23°. Growth difference is expected to be caused by the stacking order of atoms normal to the substrate surface and arrangement of atoms of the substrate surface.

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Properties of Sputter Deposited ZnO Films Co-doped with Lithium and Phosphorus

MRS Proceedings ◽

10.1557/opl.2013.4 ◽

2013 ◽

Vol 1494 ◽

pp. 77-82

Author(s):

T. N. Oder ◽

A. Smith ◽

M. Freeman ◽

M. McMaster ◽

B. Cai ◽

...

Keyword(s):

Rf Magnetron Sputtering ◽

Zno Films ◽

X Ray Diffraction ◽

X Ray ◽

Sapphire Substrates ◽

Hall Effect Measurements ◽

Sputter Deposited ◽

P Type ◽

Post Deposition ◽

Co Doped

ABSTRACTThin films of ZnO co-doped with lithium and phosphorus were deposited on sapphire substrates by RF magnetron sputtering. The films were sequentially deposited from ultra pure ZnO and Li3PO4 solid targets. Post deposition annealing was carried using a rapid thermal processor in O2 and N2 at temperatures ranging from 500 °C to 1000 °C for 3 min. Analyses performed using low temperature photoluminescence spectroscopy measurements reveal luminescence peaks at 3.359, 3.306, 3.245 eV for the co-doped samples. The x-ray diffraction 2θ-scans for all the films showed a single peak at about 34.4° with full width at half maximum of about 0.17°. Hall Effect measurements revealed conductivities that change from p-type to n-type over time.

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A Comparative Study of GaN Films Grown on Different Faces of Sapphire by ECR-Assisted MBE

MRS Proceedings ◽

10.1557/proc-242-427 ◽

1992 ◽

Vol 242 ◽

Cited By ~ 64

Author(s):

T. D. Moustakas ◽

R. J. Molnar ◽

T. Lei ◽

G. Menon ◽

C. R. Eddy

Keyword(s):

Surface Morphology ◽

Low Temperatures ◽

Smooth Surface ◽

Growth Process ◽

X Ray Diffraction ◽

Epitaxial Relationship ◽

X Ray ◽

Sapphire Substrates ◽

Growth Method ◽

Step Growth

ABSTRACTGaN films were grown on c-plane (0001), a-plane (1120) and r-plane (1102) sapphire substrates by the ECR-assisted MBE method. The films were grown using a two-step growth process, in which a GaN buffer is grown first at relatively low temperatures and the rest of the film is grown at higher temperatures. RHEED studies indicate that this growth method promotes lateral growth and leads to films with smooth surface morphology. The epitaxial relationship to the substrate, the crystalline quality and the surface morphology were investigated by RHEED, X-ray diffraction and SEM studies.

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Growth of ZnO Thin Films on Sapphire Substrates by ECR-Assisted MBE

MRS Proceedings ◽

10.1557/proc-474-395 ◽

1997 ◽

Vol 474 ◽

Author(s):

Hee-Bog Kang ◽

Kiyoshi Nakamura ◽

Kazuo Ishikawa

Keyword(s):

Sapphire Substrate ◽

Electron Cyclotron Resonance ◽

Rf Sputtering ◽

Zno Films ◽

Zno Film ◽

Epitaxial Relationship ◽

Rocking Curve ◽

Sapphire Substrates ◽

Relationship Of ◽

Ecr Source

ABSTRACTEpitaxial ZnO films were grown on c-plane sapphire substrate at low temperature using the electron cyclotron resonance-assisted molecular beam epitaxy(ECR-assisted MBE) technique. In this method, Zn vapor provided by a Knudsen cell reacts with oxygen activated in an ECR source on the surface of sapphire substrate. The crystal structure, surface morphology and epitaxial relationship of the films were investigated. It was confirmed that the ECR-assisted MBE technique was capable of growing a high quality epitaxial ZnO films on c-plane sapphire substrates at low temperatures in comparison with CVD and RF sputtering. The FWHM of an x-ray rocking curve of the (0002) peak for a 0.33μ-thick ZnO film was as narrow as 0.58°. The epitaxial relationship between ZnO film and c-plane sapphire substrate was determined to be (0001)ZnO//(0001)Al2O3 with in-plane alignment of [1100]ZnO//[2110]Al2O3, which is equivalent to the 30° rotation of ZnO relative to sapphire in the c-plane.

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Photoluminescence from ZnO Thin Film Deposited on R-Plane Sapphire Substrate by RF Magnetron Sputtering

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.388.19 ◽

2008 ◽

Vol 388 ◽

pp. 19-22 ◽

Cited By ~ 1

Author(s):

Shigeru Tanaka ◽

Yukari Ishikawa ◽

Toshiyuki Suzuki ◽

Noriyoshi Shibata

Keyword(s):

Thin Film ◽

Magnetron Sputtering ◽

Sapphire Substrate ◽

Rf Magnetron Sputtering ◽

Zno Thin Film ◽

Excitation Light ◽

Sapphire Substrates ◽

Band Emission ◽

Near Band Emission ◽

Zno Crystal

Photoluminescence from epitaxial ZnO thin films deposited on R-plane sapphire substrates by RF magnetron sputtering was investigated. The intensity of the near band emission (NBE) of the ZnO thin film on R-plane sapphire was stronger than that of the film formed on C-plane sapphire at a low temperature. Some experimental results suggest that NBE depends on the polarization of the excitation light, which are considered to be related to the ZnO crystal orientation on the sapphire substrate.

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Characterization of AlXGa1-xN Grown by MOCVD at Low Temperatures

MRS Proceedings ◽

10.1557/proc-242-421 ◽

1992 ◽

Vol 242 ◽

Author(s):

Z. J. Yu ◽

B. S. Sywe ◽

J. H. Edgar

Keyword(s):

Epitaxial Growth ◽

Low Temperatures ◽

Substrate Surface ◽

Chemical Vapor ◽

X Ray Diffraction ◽

Sapphire Substrates ◽

Electron Channelling ◽

Temperature Deposition ◽

Contrast Pattern

ABSTRACTThe low temperature deposition (400–650° C) of AlxGa1-xN films by metalorganic chemical vapor deposition (MOCVD) was characterized. Triethylgallium (TEG), trimethylaluminum (TMA), and ammonia (NH3) served as the precursors and both sapphire and silicon as the substrates with helium as the carrier gas. The deposition was operated at the atmospheric pressure. The crystallinity was improved even at low temperatures when AlxGal-xN was grown on a thin buffer layer of A1N at 400° C. With an AlxGa1-xN/AIN layered structure, epitaxial growth of AlxGa1-xN was obtained at 650° C on sapphire substrates. Auger results showed that the Al fraction x was less than 0.1. X-ray diffraction indicated a strong peak at 2θ =34.9 degrees for the (0002) planes from the film on sapphire substrates. The electron channelling pattern (ECP) of the film produced at 650° C revealed a 6 fold symmetry contrast pattern indicating the epitaxial growth of the film. Photoluminescence (PL) showed a dominant emission at 353 nm for the film on sapphire substrate. Surface morphology examined by SEM was featureless for the film produced at 500° C, while a relatively rough surface can be seen on the film produced at 650° C (5, 000x). The band gap was measured as 3.56 eV. The Al mole fraction x in the alloy was observed to be lower than that in the gas phase.

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BaTiO3 Waveguides on MgO Buffered-Sapphire Single Crystals

MRS Proceedings ◽

10.1557/proc-597-183 ◽

1999 ◽

Vol 597 ◽

Cited By ~ 2

Author(s):

Judit G. Lisoni ◽

M. Siegert ◽

C. H. Lei ◽

C. L. Jia ◽

J. Schubert ◽

...

Keyword(s):

Optical Waveguides ◽

Ferroelectric Thin Film ◽

X Ray Diffraction ◽

Epitaxial Relationship ◽

Rocking Curve ◽

Force Microscopy ◽

Sapphire Substrates ◽

Atomic Force ◽

Transmission Electron ◽

Good Crystalline Quality

AbstractWithin our program to develop ferroelectric thin film optical waveguides, we have studied the growth of epitaxial waveguides BaTiO3 on r-plane sapphire substrates with a MgO buffer layer. The films were prepared by pulsed laser deposition (PLD). Their structural properties were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), Rutherford backscattering (RBS) in random and channeling (RBS-c) configuration and atomic force microscopy (AFM). They displayed good crystalline quality, characterized by an RBS-c minimum yield of about 4–6%, a full width at half maximum (FWHM) of the XRD rocking curve measurement of the BaTiO3(200) reflection of 0.32° and a rms roughness of 1.2 nm in a film of ∼ 1.0 μm thickness. The epitaxial relationship was found to be BaTiO3(100) // MgO(100) // A12O3(1102). The refractive index, the birefringence and the optical losses have been measured.

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Epitaxial Growth of Cerium Oxide Buffer Layers on MgO, YSZ and Sapphire Substrates

MRS Proceedings ◽

10.1557/proc-619-191 ◽

2000 ◽

Vol 619 ◽

Cited By ~ 1

Author(s):

A. Thorley ◽

S. Gnanarajan ◽

A. Katsaros ◽

N. Savvides

Keyword(s):

Thin Films ◽

Epitaxial Growth ◽

Buffer Layers ◽

Metal Target ◽

X Ray Diffraction ◽

Dc Magnetron Sputtering ◽

X Ray ◽

Sapphire Substrates ◽

Pole Figures ◽

Biaxial Alignment

ABSTRACTWe studied the epitaxial growth of CeO2 thin films deposited onto MgO(100), YSZ(100) and Al2O3(1102 ) (r-plane sapphire) substrates by reactive dc magnetron sputtering of a Ce metal target in an Ar/O2 plasma. The crystalline quality and biaxial alignment of the films was determined using x-ray diffraction techniques (θ-2θ, ω-scans, pole figures, ø-scans). The CeO2/MgO(100) and CeO2/Al2O3(1102) epitaxy was evident at 600°C and developed to nearly perfect biaxial alignment at 850°C with Δø = 5° and 9° respectively. The CeO2/YSZ (100) epitaxy occurred below 300°C while deposition at ≥ 650°C led to single-crystal quality CeO2 films with Δø = 0.2°.

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Effects of Substrate Pre-deposition Annealing and Deposition Parameters on the Properties of RF Sputter-deposited ZnO Films

MRS Proceedings ◽

10.1557/opl.2012.826 ◽

2012 ◽

Vol 1394 ◽

Cited By ~ 1

Author(s):

T. N. Oder ◽

M. McMaster ◽

A. Smith ◽

N. Velpukonda ◽

D. Sternagle

Keyword(s):

Gas Flow ◽

Rf Magnetron Sputtering ◽

Zno Films ◽

X Ray Diffraction ◽

Sapphire Substrates ◽

Deposition Parameters ◽

Ultra High Purity ◽

Luminescence Peak ◽

Sputter Deposited ◽

P Type

ABSTRACTZinc Oxide thin films were deposited on sapphire substrates by radio frequency (RF) magnetron sputtering from an ultra-high purity ZnO solid target. The ZnO films were deposited on sapphire substrates heated in oxygen and/or in vacuum prior to deposition. Additional parameters investigated included the substrate temperature varied from 25 °C to 600 °C, the deposition gas pressure varied from 5 mTorr to 40 mTorr and the gas flow rate varied from 5 to 30 standard cubic centimeter per minute (sccm). The resulting films were annealed using a rapid thermal processor in N2 gas at 900 °C for 5 min. Analyses carried out using photoluminescence spectroscopy (PL) and X-ray diffraction (XRD) measurements indicate that films deposited at 300 °C using Ar:O2 (1:1) had the best optical and microstructure qualities. Pre-heating the sapphire substrate in oxygen prior to deposition was found to create a smoother sapphire surface, and this produced a ZnO film with greatly improved qualities. This film had a luminescence peak at 3.362 eV with a full-width-half maximum (FWHM) value of 15.3 meV when measured at 11 K. The XRD 2θ-scans had peaks at 34.4° with the best FWHM value of only 0.10°. Production of high quality ZnO materials is a necessary step towards realizing highly conductive p-type doped ZnO materials which is currently a major goal in research efforts on ZnO.

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