Optimization of Jc for Photo-Assisted MOCVD Prepared YBCO Thin Films by Robust Design

1993 ◽  
Vol 335 ◽  
Author(s):  
P. C. Chou ◽  
Q. Zhong ◽  
Q. L. Li ◽  
A. Ignatiev ◽  
C. Y. Wang ◽  
...  
Keyword(s):  
Thin Films ◽  
Robust Design ◽  
Flow Rate ◽  
Chemical Vapor ◽  
Preparation Technique ◽  
Superconducting Thin Film ◽  
Variable Parameters ◽  
Ybco Thin Films ◽  
Thin Film Preparation ◽  
Phase Design

AbstractMetalorganic chemical vapor deposition (MOCVD) is emerging as a practical high Tc superconducting thin film preparation technique for industrial application. Intrinsically this technique involves a large number of variable parameters. This is especially critical for the quarternary or higher high Tc materials. Thus, effective methods are required to optimize the parameters for the preparation of high Tc films. A matrix experimental design named Robust Design has been employed for this purpose. The first-phase design was based on a starting knowledge of growth temperature and pressure, and annealing temperature for MOCVD preparation of YBCO thin films. A minimum lab effort of only nine deposition experiments was then used to optimize the process control parameters of precursor oven temperature, carrier gas (Ar) flow rate, O2 flow rate and N2O flow rate. The results were then followed by three confirmation depositions. The Robust Design resulted in the growth of YBCO film with Tc consistently in the range of 87.0 K to 90.2 K and Jc improved from about 1.0 × 106 A/cm2 to 3–5 × 106 A/cm2.

Growth of Rhombohedral B12P2 Thin Films on 6H-SiC(0001) By Chemical Vapor Deposition

2003 ◽  
Vol 799 ◽  
Author(s):  
Peng Lu ◽  
J. H. Edgar ◽  
J. Pomeroy ◽  
M. Kuball ◽  
H. M. Meyer ◽  
...  
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Flow Rate ◽  
Growth Rates ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Flow Rate Ratio ◽  
Good Surface ◽  
Boron Phosphide ◽  
Moderate Growth

ABSTRACTThe parameters necessary to deposit oriented rhombohedral boron phosphide (B12P2) thin films on on-axis Si-face 6H-SiC(0001) substrates by chemical vapor deposition are reported. Ultra high purity BBr3 and PBr3 were used as reactants, with hydrogen as the carrier gas. The BBr3 to PBr3 flow rate ratio was adjusted to obtain good surface morphology of the B12P2 films. BBr3 to PBr3 ratios in the range of 1 to 1.5 produced smooth surfaces and moderate growth rates of 10μm/hr. Higher growth rates were obtained by increasing the BBr3 flow rate, but the surfaces became very rough. The c-axis of the B12P2 film was aligned with the c -axis of the substrate at temperatures between 1650°C-1700°C. The surface morphologies were investigated by SEM and the crystalline properties of the films were characterized by XRD and Raman spectroscopy.

Fabrication and characterization of ferroelectric Pb(ZrxTi1–x)O3 thin films by metalorganic chemical vapor deposition

1999 ◽  
Vol 14 (2) ◽  
pp. 487-493 ◽  
Author(s):  
Han Sang Song ◽  
Tae Song Kim ◽  
Chang Eun Kim ◽  
Hyung Jin Jung
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Metalorganic Chemical Vapor Deposition ◽  
Pyrochlore Phase ◽  
Chemical Vapor ◽  
Spectra Analysis ◽  
Pzt Thin Films ◽  
Metalorganic Chemical

Ferroelectric Pb(Zr, Ti)O3 (PZT) thin films were grown on Pt/Ti/SiO2/Si, RuO2/Pt/Ti/SiO2/Si, and Pt/MgO substrates at the substrate temperature of 600 °C by the metalorganic chemical vapor deposition (MOCVD) method. Pb(C11H19O2)2(Pb(DPM)2), Ti(OiC3H7)4, and Zr(OtC4H9)4 as source material and Ar and O2 as a carrier gas and oxidizing agent were selected, respectively. In order to investigate the effect of Zr and Ti component changes on the growth aspect of PZT thin films, Zr and Ti source materials were varied by controlling Zr and Ti flow rate. From the Rutherford backscattering spectroscopy (RBS) measurement, it was confirmed that the composition of the films, particularly Pb content, changed with the increasing Zr flow rate. In addition, the x-ray diffraction (XRD) spectra analysis showed the existence of a Pb-deficient pyrochlore phase as well as ZrO2 as a secondary phase. From these results, it is believed that the higher Zr partial pressure in the gas phase reduces the sticking of the Pb precursor to the substrate. The film with Pb:Zr:Ti = 1:0.42:0.58 showed a dielectric constant of 816 at 1 MHz. The spontaneous polarization, remanent polarization, and coercive field measured from the RT66A by applying 3.5 V were 44.1 μC/cm2, 24.4 μC/cm2, and 59.6 kV/cm, respectively. The fatigue analysis of PZT thin films with Pb:Zr:Ti = 1:0.42:0.58 at an applied voltage of Vp-p = 5.4 V showed 40% degradation on the basis of initial polarization value after 109 cycles.

scholarly journals Material Structure and Mechanical Properties of Silicon Nitride and Silicon Oxynitride Thin Films Deposited by Plasma Enhanced Chemical Vapor Deposition

Surfaces ◽  
2018 ◽  
Vol 1 (1) ◽  
pp. 59-72 ◽  
Author(s):  
Zhenghao Gan ◽  
Changzheng Wang ◽  
Zhong Chen
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Fracture Toughness ◽  
Silicon Nitride ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Silicon Oxynitride ◽  
Flow Rates ◽  
Silicon Nitride Films

Silicon nitride and silicon oxynitride thin films are widely used in microelectronic fabrication and microelectromechanical systems (MEMS). Their mechanical properties are important for MEMS structures; however, these properties are rarely reported, particularly the fracture toughness of these films. In this study, silicon nitride and silicon oxynitride thin films were deposited by plasma enhanced chemical vapor deposition (PECVD) under different silane flow rates. The silicon nitride films consisted of mixed amorphous and crystalline Si3N4 phases under the range of silane flow rates investigated in the current study, while the crystallinity increased with silane flow rate in the silicon oxynitride films. The Young’s modulus and hardness of silicon nitride films decreased with increasing silane flow rate. However, for silicon oxynitride films, Young’s modulus decreased slightly with increasing silane flow rate, and the hardness increased considerably due to the formation of a crystalline silicon nitride phase at the high flow rate. Overall, the hardness, Young modulus, and fracture toughness of the silicon nitride films were greater than the ones of silicon oxynitride films, and the main reason lies with the phase composition: the SiNx films were composed of a crystalline Si3N4 phase, while the SiOxNy films were dominated by amorphous Si–O phases. Based on the overall mechanical properties, PECVD silicon nitride films are preferred for structural applications in MEMS devices.

Effect of SiH4 Flow Rates on the Structures and Properties of Si-Rich Silicon Nitride Films Prepared by Hot Wire Chemical Vapor Deposition

2019 ◽  
Vol 288 ◽  
pp. 135-139 ◽  
Author(s):  
Yan Sai Tian ◽  
Ai Ming Gao ◽  
Bing Qing Zhou
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Silicon Nitride ◽  
Band Gap ◽  
Flow Rate ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Light Transmittance ◽  
Silicon Cluster ◽  
Hot Wire

Silicon-rich silicon nitride thin films were deposited on the P type (100) of silicon and Corning7059 glass by hot-wire chemical vapor deposition method using SiH4 and NH3 as reaction gas source. The effects of SiH4 flow rate on the structures and optical properties of the thin films were studied under optimizing other deposition parameters. The structures, band gap width and surface morphology of the thin films were characterized by Fourier transform infrared absorption spectroscopy (FTIR), ultraviolet-visible (UV-VIS) light transmittance spectra and scanning electron microscope (SEM), respectively. The experiment results show that, with increasing of the SiH4 flow rate, the content of N and Si atoms in the thin films increases, and the Si-N bond density increases gradually, and the optical band gap of the films shows a trend of increasing. When the silane flow rate is less than 0.9sccm, there is no Si-H bond stretching vibration absorption peak, and silicon atoms mainly bond with nitrogen atoms. As the SiH4 flow rate decreases, silicon clusters embedded in silicon nitride matrix gradually become smaller. When SiH4 flow rate is 0.4sccm, we prepared the silicon cluster nanoparticles with an average diameter of about 50nm embedded in silicon nitride thin films matrix. Therefore, properly reduction of the SiH4 flow rate is favorable for preparing the smaller silicon cluster nanoparticles in silicon rich silicon nitride thin films. The results lay the foundation for the preparation of silicon quantum dots thin film materials.

Optimization of Jc of YBCO thin films prepared by photo-assisted MOCVD through statistical robust design

1995 ◽  
Vol 254 (1-2) ◽  
pp. 93-112 ◽  
Author(s):  
P.C. Chou ◽  
Q. Zhong ◽  
Q.L. Li ◽  
K. Abazajian ◽  
A. Ignatiev ◽  
...  
Keyword(s):  
Thin Films ◽  
Robust Design ◽  
Ybco Thin Films
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