Seed-Free Growth of Diamond Patterns on Femtosecond Laser Processed Silicon Substrates

2013 ◽  
Vol 1511 ◽  
Author(s):  
Mengmeng Wang ◽  
Yunshen Zhou ◽  
Z. Q. Xie ◽  
Y. Gao ◽  
Lan Jiang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Femtosecond Laser ◽  
Femtosecond Lasers ◽  
Peak Position ◽  
Quality Parameter ◽  
Diamond Growth ◽  
Nucleation Density ◽  
Silicon Substrates ◽  
Diamond Nucleation ◽  
Growth Method

ABSTRACTDue to its outstanding properties, diamond is considered as an ideal material for mechanical and electric applications at high temperatures, voltages, radiation, etc. It is known that femtosecond lasers exhibit extremely high precision and minimized thermal effect in material processing. In this study, a seed-free diamond pattern growth method was developed by patterning silicon substrates using a femtosecond laser before diamond deposition through laser-assisted combustion flame synthesis. The resolution of the diamond patterns reaches micro scales. Peak position, full width at half maximum (FWHM), and diamond quality parameter were calculated from Raman spectra. The mechanism of the seed-free diamond growth based on the femtosecond laser patterning was discussed. The influence of substrates surface roughness on the diamond nucleation and subsequent growth was studied, indicating that the nucleation density is proportional to the surface roughness.

Influence of femtosecond laser on the osteogenetic efficiency of polyetheretherketone and its composite

2016 ◽  
Vol 29 (9) ◽  
pp. 997-1005 ◽  
Author(s):  
Jing Guo ◽  
Lijun Liu ◽  
Hong Liu ◽  
Kang Gan ◽  
Xiuju Liu ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Biological Activity ◽  
Femtosecond Laser ◽  
Femtosecond Lasers ◽  
Cone Beam ◽  
Test Results ◽  
Bone Implant ◽  
Peek Composite ◽  
Trabecular Bones ◽  
Push Out

Objective: This study aimed to evaluate the effect of a femtosecond laser on the osteogenetic efficiency of polyetheretherketone (PEEK) and its composite for clinical applications. Methods: One hundred pieces of PEEK and its composite (6 × 4 × 2 mm3) were randomly divided into four groups and treated as follows: group A1, PEEK; group A2, PEEK + femtosecond laser; group B1, PEEK composite; and group B2, PEEK composite + femtosecond. The surface morphology of the pieces of each group was observed through scanning electron microscopy. The surface roughness and wettability, which were considered as the main parameters affecting cell adhesion characteristics of implants, were measured. The animals whose mandibles were implanted with the four groups of materials were killed at the end of 6 and 12 weeks. Various characterization tests, such as Cone Beam Computed Tomography (CBCT), push-out test, microscope test, and bone implant contact , were conducted to investigate the healing effect between materials and bones. Results: In group B1, the nanoparticles in PEEK were uniformly distributed. In groups A2 and B2, many periodic nanostructures were observed. The surface roughness and wettability of group B2 were significantly increased compared to those of the other groups ( p < 0.05). At each time point, the number of trabecular bones, contact strength, and BIC of group B2 were higher than those of the three other groups ( p < 0.05). Compared with those of group A1, the test results of group B1 were significantly improved. Conclusion: Femtosecond lasers can effectively enhance the biological activity of PEEK and its composite; PEEK composite exhibits better biological activity than PEEK.

A pretreatment process for enhanced diamond nucleation on smooth silicon substrates coated with hard carbon films

1994 ◽  
Vol 9 (8) ◽  
pp. 2148-2153 ◽  
Author(s):  
Z. Feng ◽  
K. Komvopoulos ◽  
I.G. Brown ◽  
D.B. Bogy
Keyword(s):  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Carbon Film ◽  
Laser Raman Spectroscopy ◽  
Spherical Particles ◽  
Nucleation Density ◽  
Silicon Substrates ◽  
Pure Hydrogen ◽  
Hard Carbon ◽  
Diamond Nucleation

Diamond nucleation on unscratched silicon substrates coated with thin films of hard carbon was investigated experimentally with a microwave plasma-assisted chemical vapor deposition system. A new pretreatment process was used to enhance the nucleation of diamond. Relatively high diamond nucleation densities of ∼108 cm−2 were achieved by pretreating the carbon-coated silicon substrates with a methane-rich hydrogen plasma at a relatively low temperature for an hour. Scanning electron microscopy and laser Raman spectroscopy studies revealed that diamond nucleation occurred from nanometer-sized spherical particles of amorphous carbon produced during the pretreatment. The nanoparticles possessed a structure different from that of the original hard carbon film, with a broad non-diamond Raman peak centered at ∼1500 cm−1, and a high etching resistance in pure hydrogen plasma. The high diamond nucleation density is attributed to the significant percentage of tetrahedrally bonded (sp3) atomic carbon configurations in the nanoparticles and the presence of sufficient high-surface free-energy sites on the pretreated surfaces.

A sequential Raman analysis of the growth of diamond films on silicon substrates in a microwave plasma assisted chemical vapor deposition reactor

1997 ◽  
Vol 12 (10) ◽  
pp. 2686-2698 ◽  
Author(s):  
L. Fayette ◽  
B. Marcus ◽  
M. Mermoux ◽  
N. Rosman ◽  
L. Abello ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Sequential Analysis ◽  
Microwave Plasma ◽  
Diamond Films ◽  
Chemical Vapor ◽  
Diamond Growth ◽  
Internal Stresses ◽  
Nucleation Density ◽  
Silicon Substrates

A sequential analysis of the growth of diamond films on silicon substrates in a microwave plasma assisted chemical vapor deposition (CVD) reactor has been performed by Raman spectroscopy. The plasma was switched off during measurements, but the substrate heating was maintained to minimize thermoelastic stresses. The detectivity of the present experimental setup has been estimated to be about a few tens of μmg/cm2. From such a technique, one expects to analyze different aspects of diamond growth on a non-diamond substrate. The evolution of the signals arising from the substrate shows that the scratching treatment used to increase the nucleation density induces an amorphization of the silicon surface. This surface is annealed during the first step of deposition. The evolution of the line shape of the spectra indicates that the non-diamond phases are mainly located in the grain boundaries. The variation of the integrated intensity of the Raman signals has been interpreted using a simple absorption model. A special emphasis was given to the evolution of internal stresses during deposition. It was verified that compressive stresses were generated when coalescence of crystals took place.

The Effects of Chloromethane on Diamond Nucleation and Growth in a Hot-filament Chemical Vapor Deposition Reactor

1998 ◽  
Vol 13 (9) ◽  
pp. 2498-2504 ◽  
Author(s):  
Jih-Jen Wu ◽  
Franklin Chau-Nan Hong
Keyword(s):  
Film Growth ◽  
Chemical Vapor ◽  
Nucleation And Growth ◽  
Diamond Growth ◽  
Nucleation Density ◽  
Diamond Grit ◽  
Diamond Nucleation ◽  
Nucleation Sites ◽  
Lower Temperature ◽  
Hot Filament

The effects of chloromethane on diamond nucleation and growth were studied by employing laser reflective interferometry. Chloromethane enhances the film-growth rate only slightly compared to methane. However, chloromethane greatly enhances the nucleation density and shortens the film-forming stage, more significantly at a lower temperature. Thus, chloromethane facilitates the low temperature growth mainly through the enhancement of nucleation. Nucleation density is strongly dependent on the compositions of H atoms and carbon species prior to diamond growth. The residual diamond seeds by diamond-grit scratching are suggested to be the major nucleation sites. Chloromethane can enhance diamond nucleation by protecting the residual seeds from being etched by H atoms.

Diamond Needles And Tips As Engineered Growth Shapes

1995 ◽  
Vol 416 ◽  
Author(s):  
K. A. Cherian ◽  
J. Litster ◽  
V. Rudolph ◽  
E. T. White
Keyword(s):  
Vapour Phase ◽  
Nucleation And Growth ◽  
Crystallographic Direction ◽  
Spiral Growth ◽  
Diamond Growth ◽  
Nucleation Density ◽  
Diamond Nucleation ◽  
Practical Applications ◽  
Nucleation Sites ◽  
Double Spiral

ABSTRACTDiamond nucleation and growth by CFD were investigated to examine the possibility of engineering diamond growth shapes for practical applications. The results obtained include the following:a) Evidence supporting certain factors influencing nucleation - useful in controlling nucleation sites and nucleation density.b) Evidence for a double spiral growth mechanism operating on (111) faces under specific conditions - indicates the possibility of a new mechanism operating for diamond growth from the vapour phase, and the possibility of larger growth rates.c) Evidence for the enhanced growth in <100= crystallographic direction on a cubooctahedral crystal and its control by varying the process parameters – thus showing the possibility of obtaining diamond needles and tips as engineered growth shapes, for specific applications.

Selective Growth of Diamond Films On Mirror-Polished Silicon Substrates

1993 ◽  
Vol 334 ◽  
Author(s):  
M.Y. Mao ◽  
S.S. Tan ◽  
X.K. Zhang ◽  
W.Y. Wang
Keyword(s):  
Vapour Deposition ◽  
Microwave Plasma ◽  
Chemical Vapour ◽  
Polycrystalline Diamond ◽  
Nucleation Density ◽  
Silicon Substrates ◽  
Plasma Chemical ◽  
Diamond Nucleation ◽  
Plasma Chemical Vapour Deposition ◽  
Surface Particle

AbstractPolycrystalline diamond thin films have been selectively grown on mirror-polished silicon substrates using bias-enhanced microwave plasma chemical vapour deposition (MPCVD) to increase diamond nucleation density. A slight etching of Si02 mask was employed after the nucleation treatment to remove the diamond nuclei on the mask. Perfect diamond patterns with smooth surface (particle size <0.5µm) and sharp boundaries were obtained. The diamond film gears with 400µm in diameter and 5µm in thickness were first fabricated by this technique.

Diamond nucleation on unscratched silicon substrates coated with various non-diamond carbon films by microwave plasma-enhanced chemical vapor deposition

1995 ◽  
Vol 10 (1) ◽  
pp. 165-174 ◽  
Author(s):  
Z. Feng ◽  
M.A. Brewer ◽  
K. Komvopoulos ◽  
I.G. Brown ◽  
D.B. Bogy
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Chemical Vapor ◽  
Carbon Films ◽  
Nucleation Density ◽  
Silicon Substrates ◽  
Hard Carbon ◽  
Diamond Nucleation

The efficacy of various non-diamond carbon films as precursors for diamond nucleation on unscratched silicon substrates was investigated with a conventional microwave plasma-enhanced chemical vapor deposition system. Silicon substrates were partially coated with various carbonaceous substances such as clusters consisting of a mixture of C60 and C70, evaporated films of carbon and pure C70, and hard carbon produced by a vacuum are deposition technique. For comparison, diamond nucleation on silicon substrates coated with submicrometer-sized diamond particles and uncoated smooth silicon surfaces was also examined under similar conditions. Except for evaporated carbon films, significantly higher diamond nucleation densities were obtained by subjecting the carbon-coated substrates to a low-temperature high-methane concentration hydrogen plasma treatment prior to diamond nucleation. The highest nucleation density (∼3 × 108 cm−2) was obtained with hard carbon films. Scanning electron microscopy and Raman spectroscopy demonstrated that the diamond nucleation density increased with the film thickness and etching resistance. The higher diamond nucleation density obtained with the vacuum are-deposited carbon films may be attributed to the inherent high etching resistance, presumably resulting from the high content of sp3 atomic bonds. Microscopy observations suggested that diamond nucleation in the presence of non-diamond carbon deposits resulted from carbon layers generated under the pretreatment conditions.

Roughness measurements of nonlinear optical polymer films by scanning tunneling microscopy

1989 ◽  
Vol 47 ◽  
pp. 22-23
Author(s):  
I. H. Musselman ◽  
R.-T. Chen ◽  
P. E. Russell
Keyword(s):  
Surface Roughness ◽  
Scanning Tunneling Microscopy ◽  
Nonlinear Optical ◽  
Polymer Surface ◽  
Light Extinction ◽  
Scanning Tunneling ◽  
Silicon Substrates ◽  
Tunneling Microscopy ◽  
Optical Polymer ◽  
Total Light

Scanning tunneling microscopy (STM) has been used to characterize the surface roughness of nonlinear optical (NLO) polymers. A review of STM of polymer surfaces is included in this volume. The NLO polymers are instrumental in the development of electrooptical waveguide devices, the most fundamental of which is the modulator. The most common modulator design is the Mach Zehnder interferometer, in which the input light is split into two legs and then recombined into a common output within the two dimensional waveguide. A π phase retardation, resulting in total light extinction at the output of the interferometer, can be achieved by changing the refractive index of one leg with respect to the other using the electrooptic effect. For best device performance, it is essential that the NLO polymer exhibit minimal surface roughness in order to reduce light scattering. Scanning tunneling microscopy, with its high lateral and vertical resolution, is capable of quantifying the NLO polymer surface roughness induced by processing. Results are presented below in which STM was used to measure the surface roughness of films produced by spin-coating NLO-active polymers onto silicon substrates.

Femtosecond laser single step, full depth cutting of thick silicon sheets with low surface roughness

2021 ◽  
Vol 138 ◽  
pp. 106899
Author(s):  
Zhaoqing Li ◽  
Olivier Allegre ◽  
Qianliang Li ◽  
Wei Guo ◽  
Lin Li
Keyword(s):  
Surface Roughness ◽  
Femtosecond Laser ◽  
Single Step

Enhanced diamond nucleation on pretreated silicon substrates

1997 ◽  
Vol 301 (1-2) ◽  
pp. 77-81 ◽  
Author(s):  
Ming-Rong Shen ◽  
Hao Wang ◽  
Zhao-Yuan Ning ◽  
Chao Ye ◽  
Zhao-Qiang Gan ◽  
...  
Keyword(s):  
Silicon Substrates ◽  
Diamond Nucleation
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