Thin YSZ Electrolyte Film Depositions on Dense and Porous Substrates

Materials ◽  
2003 ◽  
Author(s):  
Zhigang Xu ◽  
Corydon Hilton ◽  
Bobby Watkins ◽  
Sergey Yarmolenko ◽  
Jag Sankar
Keyword(s):  
Growth Rate ◽  
Film Growth ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Lanthanum Manganite ◽  
Deposition Parameters ◽  
Pore Sealing ◽  
Complex Deposition ◽  
Initial Deposition ◽  
Ysz Electrolyte

Yttria stabilized zirconia (YSZ) thin films have been processed on polished silicon and porous strontium-doped lanthanum manganite (LSM) substrates by liquid fuel combustion chemical vapor deposition from combustion of an aerosol jet. The aerosol jet consists of Y- and Zr- containing metalorganics dissolved in toluene and high-purity oxygen. The morphology and thickness of the deposited films have been analyzed with scanning electron microscope. On the polished silicon substrates, thin and uniform films have been obtained. The grain growth rate is of the first order of the deposition time. The film growth rate was greatly enhanced by utilizing higher precursor concentrations, proper substrate temperature and the effect of thermophoresis. However, when the porous substrate is being coated, a more complex deposition process takes place. The initial deposition seems to be favored on the surface protrusions. Therefore, the covered areas serve as nucleation sites and the grains start to grow, giving rise to larger particles and rougher surface than the films on polished silicon. To enhance the pore-sealing rate, some pre-treatments and post-treatment have been used. Moreover, deposition parameters towards fast pore sealing have been investigated. Thin and continuous films with the film thickness less than 3 μm have been obtained.

Direct Nucleation of Crystalline SiGe on Substrates by Reactive Thermal CVD with Si2H6 and GeF4

1997 ◽  
Vol 467 ◽  
Author(s):  
Fumio Yoshizawa ◽  
Kunihiro Shiota ◽  
Daisuke Inoue ◽  
Jun-ichi Hanna
Keyword(s):  
Growth Rate ◽  
Gas Phase ◽  
Heterogeneous Nucleation ◽  
Homogeneous Nucleation ◽  
Film Growth ◽  
Early Stage ◽  
Gaseous Mixture ◽  
The Other ◽  
Thermal Cvd ◽  
Initial Deposition

ABSTRACTPolycrystalline SiGe (poly-SiGe) film growth by reactive thermal CVD with a gaseous mixture of Si2H6 and GeF4 was investigated on various substrates such as Al,Cr, Pt, Si, ITO, ZnO and thermally grown SiO2.In Ge-rich film growth, SEM observation in the early stage of the film growth revealed that direct nucleation of crystallites took place on the substrates. The nucleation was governed by two different mechanisms: one was a heterogeneous nucleation on the surface and the other was a homogeneous nucleation in the gas phase. In the former case, the selective nucleation was observed at temperatures lower than 400°C on metal substrates and Si, where the activation of adsorbed GeF4 on the surface played a major role for the nuclei formation, leading to the selective film growth.On the other hand, the direct nucleation did not always take place in Si-rich film growth irrespective of the substrates and depended on the growth rate. In a growth rate of 3.6nm/min, the high crystallinity of poly-Si0.95Ge0.05in a 220nm-thick film was achieved at 450°C due to the no initial deposition of amorphous tissue on SiO2 substrates.

On the optimization of a dc arcjet diamond chemical vapor deposition reactor

1996 ◽  
Vol 11 (3) ◽  
pp. 694-702 ◽  
Author(s):  
S. W. Reeve ◽  
W. A. Weimer ◽  
D. S. Dandy
Keyword(s):  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Film Growth ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
Methyl Radical ◽  
Chemical Kinetic Model ◽  
Model Calculations ◽  
Chemical Vapor Deposition Reactor

Based on results from chemical kinetic model calculations, a method to improve diamond film growth in a dc arcjet chemical vapor deposition reactor has been developed. Introducing the carbon source gas (CH4) into an Ar/H2 plasma in close proximity to the substrate produced diamond films exhibiting simultaneous improvements in quality and mass deposition rates. These improvements result from a reduced residence time of the methane in the plasma which inhibits the hydrocarbon chemistry in the gas from proceeding significantly beyond methyl radical production prior to encountering the substrate. Improvements in growth rate were modest, increasing by only a factor of two. Optical emission actinometry measurements indicate that the flux of atomic hydrogen across the stagnation layer to the substrate is mass diffusion limited. Since diamond growth depends upon the flux of atomic H to the substrate, these results suggest that under the conditions examined here, a low atomic H flux to the substrate poses an upper limit on the attainable diamond growth rate.

scholarly journals Numerical simulation of polysilicon deposition characteristics in chemical vapor deposition process

2018 ◽  
Vol 22 (Suppl. 2) ◽  
pp. 719-727
Author(s):  
Lisha An ◽  
Zhe Yang ◽  
Yingwen Liu ◽  
Gao Bo
Keyword(s):  
Growth Rate ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Collaborative Optimization ◽  
Transfer Model ◽  
Base Temperature ◽  
Chemical Reaction Mechanism ◽  
Silicon Growth ◽  
Detailed Chemical ◽  
Main Influence

This paper addresses the complex component evolution and silicon dynamic deposition characteristics in the traditional Siemens reactor. A two-dimensional heat and mass transfer model coupled with a detailed chemical reaction mechanism was developed. The distributions of temperature, velocity, and concentration are presented in detail. The influencing factors (such as feeding mole ratio, inlet velocity, base temperature and reactor pressure) on the molar concentration evolutions of ten major components and silicon growth rate were obtained and analyzed. Results show that base temperature is main influence of HCl mole fraction. In order to get more growth rate of silicon and better silicon quality, the complex operating parameters need to be reasonably designed on collaborative optimization.

Deposition of YSZ Thin Films by Liquid Fuel Combustion Chemical Vapor Deposition

2002 ◽  
Author(s):  
Zhigang Xu ◽  
Jag Sankar ◽  
Qiuming Wei ◽  
Jim Lua ◽  
Sergey Yamolenko ◽  
...  
Keyword(s):  
Thin Films ◽  
Growth Rate ◽  
Chemical Vapor Deposition ◽  
Substrate Temperature ◽  
Vapor Deposition ◽  
Liquid Fuel ◽  
Film Growth ◽  
Early Stage ◽  
Chemical Vapor ◽  
Nucleation Density

Thin film of YSZ electrolyte is highly desired to reduce the electrical resistance in SOFCs. YSZ thin Films have been successfully produced using liquid fuel combustion chemical vapor deposition (CCVD) technique. Nucleation of the YSZ particles were investigated based on two processing parameters, i.e., substrate temperature and total-metal-concentration in the liquid fuel. An optimum substrate temperature was found for highest the nucleation density. The nucleation density was increased with the total-metal-concentration. Microstructure evolution of the YSZ particles in the early stage in film growth was also studied. It was found that the particle growth rate was linear with processing time, and the particle orientation was varying with the time in the early stage of the film processing. To enhance the film growth rate, the effect of thermophoresis was studied. By increase the temperature gradient towards substrate, the effect of thermophoresis was enhanced and the film growth is also increased.

Trapping of Atomic Hydrogen in a-Si:H from G – D Silane Plasma

1989 ◽  
Vol 149 ◽  
Author(s):  
S. A. Cruz-Jimenez ◽  
S. Muhl ◽  
R. Salcedo
Keyword(s):  
Amorphous Materials ◽  
Film Growth ◽  
Film Formation ◽  
Chemical Vapor ◽  
Deposition Process ◽  
Full Description ◽  
Gas Phase Reactions ◽  
Hydrogen Saturation ◽  
Identical Material ◽  
Silane Plasma

Plasma Enhanced Chemical Vapor Deposition CPECVD) is used extensively for the preparation of amorphous materials. However, to date we do not have a full description of the deposition process. By this we refer to the following steps ; the source gas decomposition [1], the gas phase reactions, diffusion within the plasma [a], adsorption of the various species, solid-gas reactions, nucleation and subsequent film growth [3–7]. To a large extent the diversity of the processes which are involved in film formation explain the observed variation in the characteristics of supposedly identical material made in different laboratories. Even with such variations certain trends relating the properties of the materials with the growth processes are apparent. In particular it is well established that hydrogen saturation of the dangling bonds is essential. Although how much hydrogen is optimum, and how it is incorporated in the growing film are questions of considerable importance.

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