Microstructure Control in Mocvd PZT Thin Films

1996 ◽  
Vol 433 ◽  
Author(s):  
Daesig Kim ◽  
Tae-Young Kim ◽  
June Key Lee ◽  
W. Tao ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Process Parameters ◽  
Deposition Temperature ◽  
Ferroelectric Properties ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
Fine Grained ◽  
Pzt Films ◽  
First Time

AbstractIt was shown that Pb(ZrxTi1−x)O3 thin films (PZT) can be successfully deposited by metalorganic chemical vapor deposition (MOCVD) in a wide deposition temperature range starting from 400°C to 600°C. Variations in texture, morphology and grain size of the films as a function of process parameters were systematically investigated by x-ray diffraction (XRD) and scanning electron microscopy (SEM). The deposition temperature and gas composition in the reactor are the two key parameters that control the film microstructure. The accompanying changes in the ferroelectric properties with respect to the variations of the process parameters will also investigated. In addition, we found an interrelationship between the grain orientation and surface roughness of the films. Films with (111) preferred orientation are significantly smoother than the films with other preferred orientations. We also demonstrate, for the first time, fine grained PZT films with very low surface roughness, which show excellent electrical properties can be obtained by lowering the deposition temperature (e.g. 430°C)

Novel Mocvd Processes for Nanoscale Oxide Thin Films

1996 ◽  
Vol 446 ◽  
Author(s):  
Tingkai Li ◽  
Pete Zawadzkp ◽  
Richard A. Stall ◽  
Yongfei Zhu ◽  
Seshu B. Desu
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Integrated Circuits ◽  
Deposition Temperature ◽  
High Dielectric Constant ◽  
Ferroelectric Properties ◽  
Oxide Thin Films ◽  
High Quality ◽  
Step Process ◽  
High Dielectric

AbstractNanoscale oxide thin films such as Ba1‐xSrxTiO3 (BST), SrBi2Ta2O9 (SBT), and PbZr1‐xTixO3 (PZT) that have a high dielectric constant and excellent ferroelectric properties have been receiving greatly increased attention, especially for high density memories in next generation integrated circuits. However, with increasing deposition temperature the surface roughness of the films increases, which results in high leakage current, and when the thickness of oxide films is decreased, the apparent bulk‐like properties of thin films tend to worsen due to the increased influence of the interface. To solve these problems, novel MOCVD techniques, plasma enhanced deposition, and a two step process, were developed for high quality oxide thin films.

Optimization of the Fabrication Parameters of PZT 52/48 Thin Films by Pulsed Laser Ablation

2006 ◽  
Vol 514-516 ◽  
pp. 1353-1357 ◽  
Author(s):  
José R. A. Fernandes ◽  
Ednan Joanni ◽  
Raluca Savu
Keyword(s):  
Thin Films ◽  
Deposition Temperature ◽  
Structural Changes ◽  
Ferroelectric Properties ◽  
Strong Dependence ◽  
Michelson Interferometer ◽  
Pulsed Laser ◽  
Processing Parameters ◽  
Deposition Pressure ◽  
Pzt Films

Thin films of PbZr0,52Ti0,48O3 (PZT) for applications in piezoelectric actuators were deposited by the pulsed laser deposition technique (PLD) over Pt/Ti/SiO2/Si substrates. The effect of different electrode and PZT deposition and processing conditions on the ferroelectric and piezoelectric properties of the devices was investigated. X-Ray diffraction results showed that the deposition temperature for the electrodes had a strong influence on the PZT orientation; the increase in the electrode deposition temperature changes the PZT orientation from random or (111) to (001) depending also on PZT deposition pressure. From scanning electron microscope (SEM) pictures one could also observe that the deposition pressure affects the porosity of the PZT films, which increases with the pressure above 1×10-1 mbar for films deposited at room temperature. The measurement of the ferroelectric hysteresis curves confirmed that the structural changes induced by different processing parameters affected the ferroelectric properties of the material. The best ferroelectric properties including fatigue endurance were obtained for electrodes made at high temperature and for PZT deposited at 2×10-2 mbar and heat treated at 675°C for 30 minutes in an oxygen atmosphere. The piezoelectric coefficient d33, measured using a Michelson interferometer, had values in the range between 20 and 60 pm/V, and showed a strong dependence on the thickness of the PZT films.

SrBi2Ta2O9 thin films made by liquid source metal-organic chemical vapor deposition

1997 ◽  
Vol 12 (3) ◽  
pp. 783-792 ◽  
Author(s):  
Yongfei Zhu ◽  
Seshu B. Desu ◽  
Tingkai Li ◽  
Sasangan Ramanathan ◽  
Masaya Nagata
Keyword(s):  
Thin Films ◽  
Deposition Temperature ◽  
Ferroelectric Properties ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Organic Chemical ◽  
Liquid Source ◽  
Metal Organic ◽  
Higher Temperature ◽  
Organic Chemical Vapor Deposition

A liquid source metal-organic chemical vapor deposition system was installed to deposit SrBi2Ta2O9 (SBT) thin films on sapphire and Pt/Ti/SiO2/Si substrates. The process parameters such as deposition temperature and pressure, and ratio of Sr: Bi: Ta in the precursor solutions were optimized to achieve stoichiometric films with good reproducible ferroelectric properties. It was found that the nucleation of SBT started at a deposition temperature close to 500 °C and grain growth dominated at 700 °C and higher temperatures. With increasing deposition temperatures, the grain size of SBT thin films increased from 0.01 μm to 0.2 μm; however, the surface roughness and porosity of the films also increased. To fabricate specular SBT films, the films had to be deposited at lower temperature and annealed at higher temperature for grain growth. A two-step deposition process was developed which resulted in high quality films in terms of uniformity, surface morphology, and ferroelectric properties. The key to the success of this process was the homogeneous nucleation sites at lower deposition temperature during the first step and subsequent dense film growth at higher temperature. The two-step deposition process resulted in dense, homogeneous films with less surface roughness and improved ferroelectric properties. SBT thin films with a grain size of about 0.1 μm exhibited the following properties: thickness: 0.16–0.19 μm; 2Pr: 7.8–11.4 μC/cm2 at 5 V; Ec: 50–65 kV/cm; Ileakage: 8.0–9.5 × 10−9 Acm−2 at 150 kV/cm; dielectric constant: 100–200; and fatigue rate: 0.94–0.98 after 1010 cycles at 5 V.

Structural Evolution of Nanocrystalline Germanium Thin Films with Film Thickness and Substrate Temperature

2003 ◽  
Vol 762 ◽  
Author(s):  
William B. Jordan ◽  
Eric D. Carlson ◽  
Todd R. Johnson ◽  
Sigurd Wagner
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Grain Size ◽  
Film Thickness ◽  
Vapor Deposition ◽  
Deposition Temperature ◽  
Structural Evolution ◽  
Chemical Vapor ◽  
Force Microscopy ◽  
Atomic Force

AbstractThe structure of germanium thin films prepared on glass by plasma enhanced chemical vapor deposition was characterized by Raman spectroscopy, atomic force microscopy (AFM) and field emission scanning electron microscopy (SEM). Crystallinity, surface roughness, and grain size were measured as functions of film thickness and deposition temperature. Grain nucleation was apparent for films as thin as 10 nm. Over the thickness range studied, grain size increased with film thickness, whereas average surface roughness started to increase with film thickness, but then remained fairly constant at approximately 1 nm for a film thickness greater than 25 nm.

Analyzed by Kelvin Force Microscopy of PbZr0.3Ti0.7O3 Thin Films Grown on La0.5Sr0.5CoO3 or LaMnO3 Bottom Electrodes

2006 ◽  
Vol 306-308 ◽  
pp. 1295-1300
Author(s):  
J.S. Choi ◽  
J.S. Kim ◽  
I.S. Byun ◽  
B.H. Park
Keyword(s):  
Thin Films ◽  
Deposition Time ◽  
Ferroelectric Properties ◽  
X Ray Diffraction ◽  
Pzt Thin Films ◽  
Force Microscopy ◽  
Atomic Force ◽  
Structural And Electrical Properties ◽  
Ferroelectric Domains ◽  
Pzt Films

We have investigated structural and electrical properties of PbZr0.3Ti0.7O3 (PZT) thin films deposited by pulsed laser deposition methods. In order to improve the ferroelectric properties of PZT thin films, we have controlled grain size or surface morphology by changing bottom electrode or deposition time. PZT thin films have been deposited on La0.5Sr0.5CoO3 (LSCO) or LaMnO3 (LMO) bottom electrodes with LaAlO3 substrates during different deposition times. X-ray diffraction data have shown that all the PZT films and bottom electrodes are highly oriented with their c-axes normal to the substrates. The thickness of each film is determined by field-emission scanning electron microscope. We have also observed alternation of grain sizes (80~180 nm) by using atomic force microscopy mode and surface potential distribution and retention behavior of ferroelectric domains by using Kelvin force microscopy mode. A PZT/LMO structure has shown superior ferroelectric and retention properties to a PZT/LSCO structure.

Structural analysis of coexisting tetragonal and rhombohedral phases in polycrystalline Pb(Zr0.35Ti0.65)O3 thin films

2003 ◽  
Vol 18 (1) ◽  
pp. 173-179 ◽  
Author(s):  
Maxim B. Kelman ◽  
Paul C. McIntyre ◽  
Bryan C. Hendrix ◽  
Steven M. Bilodeau ◽  
Jeffrey F. Roeder ◽  
...  
Keyword(s):  
Thin Films ◽  
Depth Profiling ◽  
Chemical Vapor ◽  
Surface Region ◽  
Grazing Incidence ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray ◽  
Scattering Geometry ◽  
Pzt Films

Structural properties of polycrystalline Pb(Zr0.35Ti0.65)O3 (PZT) thin films grown by metalorganic chemical vapor deposition on Ir bottom electrodes were investigated. Symmetric x-ray diffraction measurements showed that as-deposited 1500 íthick PZT films are partially tetragonal and partially rhombohedral. Cross-section scanning electron microscopy showed that these films have a polycrystalline columnar microstructure with grains extending through the thickness of the film. X-ray depth profiling using the grazing-incidence asymmetric Bragg scattering geometry suggests that each grain has a bilayer structure consisting of a near-surface region in the etragonal phase and the region at the bottom electrode interface in the rhombohedral hase. The required compatibility between the tetragonal and rhombohedral phases in he proposed layered structure of the 1500 Å PZT can explain the peak shifts observed n the symmetric x-ray diffraction results of thicker PZT films.

Chemical vapor deposition of superconducting Bi-Sr-Ca-Cu-O films using fluorocarbon-based precursors

1990 ◽  
Vol 5 (1) ◽  
pp. 1-4 ◽  
Author(s):  
Masanori Nemoto ◽  
Mitsugu Yamanaka
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Diffraction Data ◽  
Vapor Deposition ◽  
Substrate Surface ◽  
Chemical Vapor ◽  
X Ray Diffraction ◽  
X Ray ◽  
Resistivity Measurements ◽  
First Time

Superconducting Bi-Sr-Ca-Cu-O thin films have been prepared for the first time by chemical vapor deposition using triphenyl bismuth and fluorocarbon-based chelates such as bis(hexafluoroacetylacetonate)strontium, bis(hexafluoroacetylacetonate)calcium, and bis(hexafluoroacetylacetonate)copper. After annealing in air, x-ray diffraction data reveal that the films deposited on (001) SrTiO3 substrates have preferential orientation of their crystalline c-axis perpendicular to the substrate surface. Four-probe resistivity measurements reveal the onset of superconductivity at 80 K and zero resistivity at 50 K.

Ba substituted Pb(ZrxTi1-x)O3 thin films grown by MOCVD

2005 ◽  
Vol 902 ◽  
Author(s):  
Jochen Puchalla ◽  
Susanne Hoffmann-Eifert ◽  
Lorena Cattaneo ◽  
Sergio Carella ◽  
Rainer Waser
Keyword(s):  
Thin Films ◽  
Relative Permittivity ◽  
Ferroelectric Properties ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Orientation Dependence ◽  
Organic Chemical ◽  
Process Conditions ◽  
Si Substrates ◽  
Pzt Films

AbstractHigh quality Pb(Zr,Ti)O3 [PZT] and (Pb1-xBax)(ZryTi1-y)O3 (x ≤ 0.15, 0.25 ≤ y ≤ 0.50) [PBZT] thin films were grown on Pt (111) and Ir (111) coated silicon substrates by means of a pulsed liquid injection metal organic chemical vapor deposition (MOCVD) technique. The precursor solutions of Pb(DPM)2, Ba(DPM)2, Zr(IBPM)4, and Ti(OiPr)2(DPM)2 dissolved in butylacetate were separately injected into an AIX-200 reactor using a TriJet™ vaporizer. Stoichiometric films (0.98 ≤ A/B ≤ 1.06) with thickness between 80 nm and 150 nm were deposited at a susceptor temperature of 615 °C to 660 °C. Pure PZT films grown on platinum coated substrates show a randomly oriented perovskite structure accompanied with formation of a PbPtx alloy at the PZT/Pt interface. On the Ir(111) coated substrates the pure PZT films also exhibit a random orientation possibly due to oxidation of the Ir surface layer during the deposition process. Ferroelectric properties of Pr = 35 µC/cm2 and Ec = 90 kV/cm were obtained for a PZT (30/70) film of 150 nm thickness grown on Ir/Si. In contrast, PBZT films with a Ba content of about 5 to 15% show lower tendency for formation of a PbPtx interfacial layer, and a preferred (111) texture was observed for PBZT films grown on the Ir (111) substrates under optimized process conditions. Tetragonal and rhombohedral PBZT films with 15% Ba and a Zr-content of about 0.35 and 0.50, respectively, show an orientation dependence of the ferroelectric properties in the way that Ec is highest for <111> textured films in comparison to Ec determined for <110> textured films. The remanent polarization of 85 nm thick tetragonal PBZT films changes from 17 µC/cm2 for <111> orientation to 13.5 µC/cm2 for <110> texture. The relative permittivity changes in the same way from 600 to 540, respectively. The rhombohedral films exhibit a nearly independent Pr value of about 11 µC/cm2 while the switching field changes from 75 kV/cm for an <111> textured film to 46 kV/cm for an (110) textured one. The relative permittivity values of both films are 890 and 715 for the (110) and the (111) textured films, respectively. The trends observed for the textured PBZT films grown on Si substrates reflect the behaviour reported for epitaxial films [2]

scholarly journals A novel and potentially scalable CVD-based route towards SnO2:Mo thin films as transparent conducting oxides

2021 ◽  
Author(s):  
Tianlei Ma ◽  
Marek Nikiel ◽  
Andrew G. Thomas ◽  
Mohamed Missous ◽  
David J. Lewis
Keyword(s):  
Thin Films ◽  
Photoelectron Spectroscopy ◽  
Mixed Valence ◽  
Chemical Vapour ◽  
X Ray Diffraction ◽  
X Ray ◽  
Conducting Oxides ◽  
Valence States ◽  
3 Omega ◽  
First Time

AbstractIn this report, we prepared transparent and conducting undoped and molybdenum-doped tin oxide (Mo–SnO2) thin films by aerosol-assisted chemical vapour deposition (AACVD). The relationship between the precursor concentration in the feed and in the resulting films was studied by energy-dispersive X-ray spectroscopy, suggesting that the efficiency of doping is quantitative and that this method could potentially impart exquisite control over dopant levels. All SnO2 films were in tetragonal structure as confirmed by powder X-ray diffraction measurements. X-ray photoelectron spectroscopy characterisation indicated for the first time that Mo ions were in mixed valence states of Mo(VI) and Mo(V) on the surface. Incorporation of Mo6+ resulted in the lowest resistivity of $$7.3 \times 10^{{ - 3}} \Omega \,{\text{cm}}$$ 7.3 × 10 - 3 Ω cm , compared to pure SnO2 films with resistivities of $$4.3\left( 0 \right) \times 10^{{ - 2}} \Omega \,{\text{cm}}$$ 4.3 0 × 10 - 2 Ω cm . Meanwhile, a high transmittance of 83% in the visible light range was also acquired. This work presents a comprehensive investigation into impact of Mo doping on SnO2 films synthesised by AACVD for the first time and establishes the potential for scalable deposition of SnO2:Mo thin films in TCO manufacturing. Graphical abstract

scholarly journals Reactive Dual Magnetron Sputtering: A Fast Method for Preparing Stoichiometric Microcrystalline ZnWO4 Thin Films

Surfaces ◽  
2021 ◽  
Vol 4 (2) ◽  
pp. 106-114
Author(s):  
Yannick Hermans ◽  
Faraz Mehmood ◽  
Kerstin Lakus-Wollny ◽  
Jan P. Hofmann ◽  
Thomas Mayer ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetron Sputtering ◽  
Photoelectron Spectroscopy ◽  
Fast Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Glass Substrates ◽  
Post Annealing ◽  
Rf Signal ◽  
First Time

Thin films of ZnWO4, a promising photocatalytic and scintillator material, were deposited for the first time using a reactive dual magnetron sputtering procedure. A ZnO target was operated using an RF signal, and a W target was operated using a DC signal. The power on the ZnO target was changed so that it would match the sputtering rate of the W target operated at 25 W. The effects of the process parameters were characterized using optical spectroscopy, X-ray diffraction, and scanning electron microscopy, including energy dispersive X-ray spectroscopy as well as X-ray photoelectron spectroscopy. It was found that stoichiometric microcrystalline ZnWO4 thin films could be obtained, by operating the ZnO target during the sputtering procedure at a power of 55 W and by post-annealing the resulting thin films for at least 10 h at 600 °C. As FTO coated glass substrates were used, annealing led as well to the incorporation of Na, resulting in n+ doped ZnWO4 thin films.

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