scholarly journals Effects of surface treatment of silicon substrate on nucleation density of diamond synthesized in gas phase.

1990 ◽  
Vol 56 (5) ◽  
pp. 923-928 ◽  
Author(s):  
Masaoki YAMAMOTO ◽  
Takayuki SHIBATA ◽  
Katsumasa SAITOH
Keyword(s):  
Surface Treatment ◽  
Gas Phase ◽  
Silicon Substrate ◽  
Nucleation Density

Influences of surface treatment on In0.53Ga0.47As epitaxial layer grown on silicon substrate using trimethylaluminum

2018 ◽  
Vol 646 ◽  
pp. 173-179
Author(s):  
Soo Bin Kim ◽  
Seung Hyun Lee ◽  
Hae Jun Jung ◽  
Myung Su Seo ◽  
Sung Min Kim ◽  
...  
Keyword(s):  
Surface Treatment ◽  
Epitaxial Layer ◽  
Silicon Substrate

Coalesced oriented diamond films on nickel

1998 ◽  
Vol 13 (5) ◽  
pp. 1120-1123 ◽  
Author(s):  
P. C. Yang ◽  
C. A. Wolden ◽  
W. Liu ◽  
R. Schlesser ◽  
R. F. Davis ◽  
...  
Keyword(s):  
Gas Phase ◽  
Profile Analysis ◽  
Substrate Surface ◽  
Diamond Films ◽  
Diamond Powder ◽  
Hydrogen Atmosphere ◽  
Nucleation Density ◽  
Annealing Stage ◽  
Multistep Process ◽  
Degree Of Orientation

The growth of coalesced, highly oriented diamond films has been achieved on nickel substrates using a multistep process that consisted of (i) seeding the Ni surface with 0.5 μm diamond powder, (ii) annealing at 1100 °C in a hydrogen atmosphere, and (iii) growth at 900 °C in a mixture of hydrogen and 0.5% methane. Auger depth profile analysis of a sample quenched after the annealing stage showed the presence of significant amounts of carbon (6 at. %) close to the substrate surface and about 3 at.% deeper in the substrate. The loss of carbon into the substrate resulted in relatively low nucleation density. The addition of methane into the gas phase during the annealing stage proved very effective in compensating for the diffusion. An addition of 0.5% methane in the gas phase produced optimum results, as the nucleation density, orientation of diamond particles, and uniformity were substantially improved. Substrates nucleated under these conditions were grown out into coalesced, 30 μm thick films. Both (100) and (111) oriented films showed a high degree of orientation and Raman spectra obtained from these orientations showed intense and narrow diamond signature peaks with FWHM's of 5 and 8 cm-1, respectively.

Effects of Starting Materials on Preparation and Properties of Pure SiC Ceramics via the HTPVT Method

2019 ◽  
Vol 889 ◽  
pp. 3-9
Author(s):  
Yu Chen Deng ◽  
Nan Long Zhang ◽  
Ya Ming Zhang ◽  
Bo Wang ◽  
Jian Feng Yang
Keyword(s):  
Grain Size ◽  
High Temperature ◽  
Gas Phase ◽  
Vapor Transport ◽  
Nucleation Density ◽  
Flexure Strength ◽  
Nucleation Stage ◽  
Sic Ceramics ◽  
Initial Nucleation ◽  
Average Grain Size

The method of high temperature physical vapor transport (HTPVT) is an available approach to prepare silicon carbide (SiC) ceramics with high density and high purity. In the present work, α-SiC (6H-SiC) and β-SiC (3C-SiC) powders were used as starting materials respectively to fabricate SiC ceramics with HTPVT process, and the effects of starting materials on nucleation, density, microstructure and mechanical properties of SiC ceramics were investigated. It showed that at high temperature, the decomposition rate of β-SiC was higher than that of α-SiC, and at the initial nucleation stage, the average grain size of SiC crystal obtained with β-SiC starting materials was smaller than that with α-SiC starting materials, because higher vapour pressure of gas phase which decomposed by β-SiC starting materials facilitated nucleation and growth of SiC grains. Density of the resulted SiC ceramics using α-SiC and β-SiC as starting materials was 3.16 g·cm-3 and 3.17 g·cm-3, indicating close values, while, using β-SiC as the starting materials, the grain size was smaller, consequently, the flexure strength was higher. Increasing growth temperature from 2200°C to 2300°C, the densities and the flexure strength of the SiC ceramics using either α-SiC or β-SiC were decreased.

Effect of Gas Phase Hydrogen-Dilution on the Nucleation, Growth, and Interfaces Of a-Si1-xCx:H

1993 ◽  
Vol 297 ◽  
Author(s):  
Yiwei Lu ◽  
Ilsin An ◽  
M. Gunes ◽  
M. Wakagi ◽  
C.R. Wronski ◽  
...  
Keyword(s):  
Gas Phase ◽  
Vapor Deposition ◽  
Metal Contamination ◽  
Chemical Vapor ◽  
Nucleation Density ◽  
Causal Connection ◽  
Flow Ratio ◽  
Optical Gap ◽  
Hydrogen Dilution ◽  
Extensive Surface

The microstructural evolution of a-Si1-xCx:H with an optical gap of 1.95 eV, prepared by plasma-enhanced chemical vapor deposition (PECVD), has been studied versus gas phase H2- dilution by real time spectroscopic ellipsometry. As the H2/(CH4+SiH4) flow ratio is increased to 24, the monolayer-scale features of the growth process suggest an enhancement in precursor diffusion on substrate and film surfaces. Such features include a reduction in nucleation density, extensive surface smoothening during coalescence, and an increase the structural stability and density of the final film. We suggest a causal connection between these characteristics, and the photoelectronic properties of the film, which also improve with H2-dilution. Potentially detrimental effects of H2 dilution when a-Si1-xCx:H is deposited on TCO’s, including metal contamination at interfaces with Sn02 and H-diffusion into ZnO, are also characterized.

The Influence Of Stress on The Growth of Titanium Silicide Thin Films on (001) Silicon Substrates

1999 ◽  
Vol 564 ◽  
Author(s):  
S. L. Cheng ◽  
S. M. Chang ◽  
H. Y. Huang ◽  
Y. C. Peng ◽  
L. J. Chen ◽  
...  
Keyword(s):  
Tensile Stress ◽  
Silicon Substrate ◽  
Function Analysis ◽  
Titanium Silicide ◽  
Nucleation Density ◽  
Silicon Substrates ◽  
Auto Correlation ◽  
Nucleation Sites ◽  
Auto Correlation Function ◽  
Ti Films

AbstractThe influence of stress on the enhanced formation of C54-TiSi2 phase has been investigated. Tensile stress induced by backside CoSi2 film on the silicon substrate has been found to enhance the growth of C54-TiSi2 on (001)Si. The thickness of amorphous interlayers (a-interlayers) between Ti films and silicon substrates was found to be thicker and thinner in the tensilly and compressively stressed samples, respectively. From auto-correlation function analysis, the thicker a-interlayer was found to consist of a higher density of crystallites. The crystallites provide nucleation sites for C49-TiSi2 and facilitate the formation of C49-TiSi2 of small size. The larger total area of C49-TiSi2 grain boundaries supplies more nucleation sites for the phase transformation of C49- to C54-TiSi2. Therefore, the tensile stress present in the silicon substrate promotes the formation of a-interlayer and decreases the grain size of C49- TiSi2, which increases the nucleation density of the C54-TiSi2 phase. As a result, the transformation of C49- to C54-TiSi2 phase is enhanced.

Methylamine Growth of SiCN Films Using ECR-CVD

1999 ◽  
Vol 606 ◽  
Author(s):  
C.-Y. Wen ◽  
J.-J. Wu ◽  
H.J. Lo ◽  
L.C. Chen ◽  
K.H. Chen ◽  
...  
Keyword(s):  
Carbon Source ◽  
Carbon Content ◽  
Band Gap ◽  
Gas Phase ◽  
Wide Band ◽  
Point Of View ◽  
Nucleation Density ◽  
Wide Band Gap ◽  
Direct Band ◽  
Lower Carbon

AbstractContinuous polycrystalline SiCN films with high nucleation density have been successfully deposited by using CH3NH2, as carbon source gas in an ECR-CVD reactor. Fom the kinetic point of view, using CH3NH2, as carbon source could provide more abundant active carbon species in the gas phase to enhance the carbon incorporation in the SiCN films. The compositions of the SiCN films analyzed from Rutherford Backscattering Spectroscopy showed that higher [CH3NH2,]/[SiH4] ratio led to higher carbon content in the films. Moreover, a lower carbon content was measured when the film was deposited at higher substrate temperature. The direct band gap of the aforementioned SiCN films determined using PzR is around 4.4 eV, indicating a wide band gap material for blue-UV optoelectronics.

Evidence for nonclassical nucleation at solid surfaces in diamond deposition from the gas phase

1993 ◽  
Vol 8 (7) ◽  
pp. 1596-1604 ◽  
Author(s):  
Massimo Tomellini
Keyword(s):  
Gas Phase ◽  
Active Site ◽  
Rate Constants ◽  
Solid Surfaces ◽  
Silicon Surfaces ◽  
Necessary Condition ◽  
Nucleation Density ◽  
Diamond Deposition ◽  
Diamond Nucleation ◽  
Step Model

In the framework of a previously developed kinetic model, a discriminating criterion is established to distinguish between classical and nonclassical nucleation of diamond at solid surfaces. The two-step model gives the non-steady-state nucleation density function in terms of the rate constants for active site → germ, germ → active site, and germ → nucleus kinetic steps. The criterion states that α/β > 6 is a necessary condition for classical nucleation at surfaces to occur, α and β being functions of the rate constants which can be obtained by appropriate analysis of the experimental data. This criterion is applied to recent results on diamond nucleation at silicon surfaces and indicates nonclassical results The expression of the nonequilibrium Zeldovich factor, Z, is also found in the form Z = [1 + K/nd]−1, K and nd being the rate constants for the germ → nucleus and germ → active site steps, respectively. An estimation of the rate constants is reported and the corresponding Zeldovich factor is evaluated to be 0.6 for nucleation at both Si(100) and Si(111) substrates.

Effect of gas phase composition cycling on diamond nucleation density

2003 ◽  
Vol 425 (1-2) ◽  
pp. 282-286 ◽  
Author(s):  
S.-H Kim ◽  
E.-J Bae ◽  
J.C Park ◽  
T.-G Kim ◽  
S.K Lee ◽  
...  
Keyword(s):  
Phase Composition ◽  
Gas Phase ◽  
Nucleation Density ◽  
Diamond Nucleation
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