Growth of BaTiO3 Thin Films by MOCVD

1993 ◽  
Vol 335 ◽  
Author(s):  
Debra L. Kaiser ◽  
Mark D. Vaudin ◽  
Greg Gillen ◽  
Cheol-Seong Hwang ◽  
Lawrence H. Robins ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Chemical Vapor ◽  
Titanium Isopropoxide ◽  
Elevated Pressure ◽  
Process Gas ◽  
Polycrystalline Thin Films ◽  
Transmission Electron ◽  
Quartz Substrates ◽  
Secondary Ion

AbstractPolycrystalline thin films of BaTiO3 were deposited on fused quartz substrates at 600°C by metalorganic chemical vapor deposition (MOCVD). The films were characterized by x-ray powder diffraction (XRD), transmission electron microscopy (TEM), secondary ion mass spectroscopy (SIMS) and Raman spectroscopy. Films prepared in the early stages of this study that had appeared to contain only crystalline BaTiO3 by XRD were found to have nonuniform composition and microstructure through the film thickness by SIMS and TEM. The MOCVD system was then modified by installing a process gas bypass apparatus and an elevated pressure bubbler for the titanium isopropoxide precursor. A 1.2 μm thick BaTiO3 film prepared in the modified system demonstrated much improved compositional and microstructural uniformity through the thickness of the film. This film had a columnar microstructure with grain widths of 0.1–0.2 μm and exhibited tetragonality as detected by Raman spectroscopy.

Ultra-high vacuum chemical vapor deposition and in situ characterization of titanium oxide thin films

1991 ◽  
Vol 6 (9) ◽  
pp. 1913-1918 ◽  
Author(s):  
Jiong-Ping Lu ◽  
Rishi Raj
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Titanium Oxide ◽  
Vapor Deposition ◽  
Photoelectron Spectroscopy ◽  
High Vacuum ◽  
Chemical Vapor ◽  
Titanium Isopropoxide ◽  
Ultra High Vacuum

Chemical vapor deposition (CVD) of titanium oxide films has been performed for the first time under ultra-high vacuum (UHV) conditions. The films were deposited through the pyrolysis reaction of titanium isopropoxide, Ti(OPri)4, and in situ characterized by x-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). A small amount of C incorporation was observed during the initial stages of deposition, through the interaction of precursor molecules with the bare Si substrate. Subsequent deposition produces pure and stoichiometric TiO2 films. Si–O bond formation was detected in the film-substrate interface. Deposition rate was found to increase with the substrate temperature. Ultra-high vacuum chemical vapor deposition (UHV-CVD) is especially useful to study the initial stages of the CVD processes, to prepare ultra-thin films, and to investigate the composition of deposited films without the interference from ambient impurities.

Characterization of Highly Textured PZT Thin Films Grown on LaNiO3 Coated Si Substrates by MOCVD

1997 ◽  
Vol 493 ◽  
Author(s):  
C. H. Lin ◽  
B. M. Yen ◽  
Haydn Chen ◽  
T. B. Wu ◽  
H. C. Kuo ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Fatigue Behavior ◽  
Chemical Vapor ◽  
Dielectric Constants ◽  
Preferential Orientation ◽  
Organic Chemical ◽  
Pzt Thin Films ◽  
Si Substrates ◽  
Transmission Electron

ABSTRACTHighly textured PbZrxTi1−xO3 (PZT) thin films with x= 0-0.6 were grown on LaNiO3 coated Si substrates at 600 °C by metal-organic chemical vapor deposition (MOCVD). The preferred crystalline orientation of PZT thin films with various Zr concentration were characterized by X-ray diffraction (XRD). Microstructures were studied by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The dielectric constants, hysteresis and fatigue behavior of these thin films were also measured. The relationship between growth rate and the preferential orientation is discussed. Furthermore, the dependence of the electrical properties on Zr concentration and preferential orientation is demonstrated.

Microstructural Characterization of GaN Grown on SiC

2019 ◽  
Vol 25 (6) ◽  
pp. 1383-1393
Author(s):  
Sabyasachi Saha ◽  
Deepak Kumar ◽  
Chandan K. Sharma ◽  
Vikash K. Singh ◽  
Samartha Channagiri ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Raman Spectroscopy ◽  
Surface Morphology ◽  
Chemical Vapor ◽  
Microstructural Characterization ◽  
Organic Chemical ◽  
Nucleation Layer ◽  
Transmission Electron ◽  
Vapor Deposition Technique ◽  
Metal Organic

AbstractGaN films have been grown on SiC substrates with an AlN nucleation layer by using a metal organic chemical vapor deposition technique. Micro-cracking of the GaN films has been observed in some of the grown samples. In order to investigate the micro-cracking and microstructure, the samples have been studied using various characterization techniques such as optical microscopy, atomic force microscopy, Raman spectroscopy, scanning electron microscopy and transmission electron microscopy (TEM). The surface morphology of the AlN nucleation layer is related to the stress evolution in subsequent overgrown GaN epilayers. It is determined via TEM evidence that, if the AlN nucleation layer has a rough surface morphology, this leads to tensile stresses in the GaN films, which finally results in cracking. Raman spectroscopy results also suggest this, by showing the existence of considerable tensile residual stress in the AlN nucleation layer. Based on these various observations and results, conclusions or propositions relating to the microstructure are presented.

Epitaxial Ferroelectric BaTiO3 Thin Films for Microphotonic Applications

2000 ◽  
Vol 637 ◽  
Author(s):  
F. Niu ◽  
A.R. Teren ◽  
B.H. Hoerman ◽  
B.W. Wessels
Keyword(s):  
Thin Films ◽  
Chemical Vapor ◽  
Silicon Substrates ◽  
X Ray Diffraction ◽  
Insulating Layer ◽  
Ferroelectric State ◽  
Transmission Electron ◽  
Electro Optic ◽  
Metal Organic ◽  
Mgo Layers

AbstractEpitaxial ferroelectric BaTiO3 thin films have been developed as a material for microphotonics. Efforts have been directed toward developing these materials for thin film electro-optic modulators. Films were deposited by metalorganic chemical vapor deposition (MOCVD) on both MgO and silicon substrates. The electro-optic properties of the thin films were measured. For BaTiO3 thin films grown on (100) MgO substrates, the effective electro-optic coefficient, reff depended on the magnitude and direction of the electric field. Coefficients as high as 260 pm/V have been measured. Investigation of BaTiO3 films on silicon has been undertaken. Epitaxial BaTiO3 thin films were deposited by MOCVD on (100) MgO layers grown on silicon (100) substrates by metal-organic molecular beam epitaxy (MOMBE). The MgO serves as the low index optical cladding layer as well as an insulating layer. X-ray diffraction and transmission electron microscopy (TEM) indicated that BaTiO3 was epitaxial with an orientational relation given by BaTiO3 (100)//Si (100) and BaTiO3[011]//Si [011]. Polarization measurements indicated that the BaTiO3 epitaxial films on Si were in the ferroelectric state.

Omcvd Elaboration and Characterization of Silicon Carbide and Carbon-Silicon Carbide Films from Organosilicon Compounds

1992 ◽  
Vol 271 ◽  
Author(s):  
R. Morancho ◽  
A. Reynes ◽  
M'b. Amjoud ◽  
R. Carles
Keyword(s):  
Thin Films ◽  
Silicon Carbide ◽  
Raman Spectroscopy ◽  
Chemical Vapor Deposition ◽  
Thermal Behavior ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Organosilicon Compounds ◽  
Carrier Gas

ABSTRACTTwo organosilicon molecules tetraethysilane (TESi) and tetravinylsilane (TVSi) were used to prepare thin films of silicon carbide by chemical vapor deposition (C. V. D.). In each of the molecule, the ratio C/Si = 8, the only difference between TESi and TVSi is the structure of the radicals ethyl (.CH2-CH3) and vinyl (.CH=CH2). This feature induces different thermal behavior and leads to the formation of different materials depending on the nature of the carrier gas He or H2· The decomposition gases are correlated with the material deposited which is investigated by I.R. and Raman spectroscopy. The structure of the starting molecule influences the mechanisms of decomposition and consequently the structure of the material obtained.

Observations of Domain Structure at Initial Growth Stage of PbTiO3 Thin Films Grown by Mocvd

1999 ◽  
Vol 596 ◽  
Author(s):  
H. Fujisawa ◽  
M. Shimizu ◽  
H. Niu ◽  
K. Honda ◽  
S Ohtani
Keyword(s):  
Thin Films ◽  
Domain Structure ◽  
Growth Stage ◽  
Domain Walls ◽  
Chemical Vapor ◽  
Initial Growth ◽  
Continuous Film ◽  
Cross Sectional ◽  
Initial Growth Stage ◽  
Transmission Electron

AbstractDomain structure and growth mechanism of PbTiO3 thin films were investigated using a transmission electron microscopy(TEM) from the viewpoint of size effects. At initial growth stage of (111)-oriented PbTiO3 films prepared by metalorganic chemical vapor deposition(MOCVD), triangle-shaped islands were grown on Pt(111)/SiO2/Si before becoming a continuous film. Triangular islands grew gradually in a lateral dimension. This means that PbTiO3 films grew two-dimensionally at initial growth stage. In cross-sectional TEM photomicrographs, (101)-twin boundaries (90° domain walls) and inclination of {110} or {101}-plane were observed in PbTiO3 islands. This result indicates that such small PbTiO3 islands have a tetragonal structure and could have spontaneous polarization. The minimum island which had 90° domain walls was 10nm high and 18nm wide.

Structural studies of diamond thin films grown from dc arc plasma

1997 ◽  
Vol 12 (10) ◽  
pp. 2533-2542 ◽  
Author(s):  
L. C. Nistor ◽  
J. Van Landuyt ◽  
V. G. Ralchenko ◽  
A. A. Smolin ◽  
K. G. Korotushenko ◽  
...  
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Arc Discharge ◽  
Stacking Faults ◽  
Argon Laser ◽  
Arc Plasma ◽  
Structural Studies ◽  
Transmission Electron ◽  
Diamond Thin Films ◽  
Dc Arc

Diamond thin films grown from a dc-arc discharge in CH4/H2 mixtures on Si wafers were examined by transmission electron microscopy and Raman spectroscopy. This deposition method provides good diamond crystallinity at high CH4 concentrations (3%–9%). Seeding the substrate with 5 nm diamond particles at a density of 2 × 1012 cm−1 followed by argon laser irradiation to reduce their agglomeration gives, just after starting deposition, a density of growth centers of 1010cm−2. At 3% CH4 concentration the film grows with almost perfect crystallites. Richer CH4 mixtures (5% and 9%) produce crystallites with twins and stacking faults. An amorphous 20–70 nm SiC interlayer is present at these CH4 concentrations, which was not observed at 3% CH4. Amorphous sp3- and sp2-bonded carbon was detected by Raman spectroscopy at all CH4 concentrations and correlated with TEM data.

Study on integration of aluminum-doped zinc oxide (AZO) thin films with graphene oxide (GO)

2018 ◽  
Vol 32 (19) ◽  
pp. 1840044
Author(s):  
Aditya Dalal ◽  
Animesh Mandal ◽  
Shubhada Adhi ◽  
Kiran Adhi
Keyword(s):  
Thin Films ◽  
Raman Spectroscopy ◽  
Graphene Oxide ◽  
X Ray Diffraction ◽  
Visible Spectroscopy ◽  
X Ray ◽  
Transmission Electron ◽  
Vis Spectroscopy ◽  
Aluminum Doped Zinc Oxide ◽  
Uv Visible

Aluminum (0.5 at.%)-doped ZnO (AZO) thin films were deposited by pulsed laser deposition technique (PLD) in oxygen ambient of 10[Formula: see text] Torr. The deposited thin films were characterized by x-ray diffraction (XRD), photoluminescence (PL), Raman spectroscopy and uv–visible spectroscopy (UV–vis). Next, graphene oxide (GO) was synthesized by Hummers method and was characterized by XRD, UV–vis spectroscopy, Raman spectroscopy and transmission electron microscopy (TEM). Thereafter, GO solution was drop-casted on AZO thin films. These films were then characterized by Raman Spectroscopy, UV–vis spectroscopy and PL. Attempt is being made to comprehend the modifications in properties brought about by integration.

Sol-gel processing of nanocrystalline haematite thin films

1997 ◽  
Vol 12 (6) ◽  
pp. 1441-1444 ◽  
Author(s):  
L. Armelao ◽  
A. Armigliato ◽  
R. Bozio ◽  
P. Colombo
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Transmission Electron Microscopy ◽  
Raman Spectroscopy ◽  
Sol Gel ◽  
X Ray Diffraction ◽  
Single Particles ◽  
X Ray ◽  
Transmission Electron ◽  
Gel Processing

The microstructure of Fe2O3 sol-gel thin films, obtained from Fe(OCH2CH3)3, was investigated by x-ray diffraction (XRD), transmission electron microscopy (TEM), and Raman spectroscopy. Samples were nanocrystalline from 400 °C to 1000 °C, and the crystallized phase was haematite. In the coatings, the α–Fe2O3 clusters were dispersed as single particles in a network of amorphous ferric oxide.

Observation of Redshifts of Photoluminescence from Thin Films Assembled by CuCl Nanoclusters

1997 ◽  
Vol 11 (06) ◽  
pp. 275-281
Author(s):  
Bingyou Miao ◽  
Jianmin Hong ◽  
Pingping Chen ◽  
Xiaoli Yuan ◽  
Min Han ◽  
...  
Keyword(s):  
Thin Films ◽  
Quantum Confinement ◽  
Phonon Coupling ◽  
Transmission Electron ◽  
Two Samples ◽  
Evaporation Technique ◽  
The Mean ◽  
Quartz Substrates ◽  
Cucl Nanocrystals ◽  
Gas Evaporation Technique

Two samples of thin films, assembled by CuCl nanoclusters, have been prepared by the gas evaporation technique. The CuCl nanoclusters were deposited on monocrystalline silicon and quartz substrates and then coated with a layer of NaCl to prevent oxidation of the CuCl nanoclusters. From transmission electron microscope and selected area diffraction, it is clear that the two samples consist of CuCl nanocrystals and Cu aggregates and the mean diameters are about 3 nm and 6 nm. From the absorption and photoluminescence (PL) spectra of the two samples carried out at ~300 K, we found that the peaks of exciton absorption do not show up and luminescence peaks shift to lower energies, possibly due to the strong coupling between exciton and phonon. At 77 K, the PL peaks of excitons broadened by exciton–phonon coupling have been observed, in approximate agreement with the values calculated by the quantum confinement model. The broad peaks of emission from trapped states or bands have also been observed at 77 K. In addition, the interaction between exciton and phonon is stronger in the sample with mean diameter about 3 nm according to a larger broadening and redshift of the PL peak from excitons, in qualitative agreement with theoretical prediction.

Sign in / Sign up

Export Citation Format

Share Document