scholarly journals Microstructures Manufactured in Diamond by Use of Laser Micromachining

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1199
Author(s):  
Mariusz Dudek ◽  
Adam Rosowski ◽  
Marcin Kozanecki ◽  
Malwina Jaszczak ◽  
Witold Szymański ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Raman Spectra ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Scanning System ◽  
Carbon Phase ◽  
Diamond Plate ◽  
Diode Pumped

Different microstructures were created on the surface of a polycrystalline diamond plate (obtained by microwave plasma-enhanced chemical vapor deposition—MW PECVD process) by use of a nanosecond pulsed DPSS (diode pumped solid state) laser with a 355 nm wavelength and a galvanometer scanning system. Different average powers (5 to 11 W), scanning speeds (50 to 400 mm/s) and scan line spacings (“hatch spacing”) (5 to 20 µm) were applied. The microstructures were then examined using scanning electron microscopy, confocal microscopy and Raman spectroscopy techniques. Microstructures exhibiting excellent geometry were obtained. The precise geometries of the microstructures, exhibiting good perpendicularity, deep channels and smooth surfaces show that the laser microprocessing can be applied in manufacturing diamond microfluidic devices. Raman spectra show small differences depending on the process parameters used. In some cases, the diamond band (at 1332 cm−1) after laser modification of material is only slightly wider and shifted, but with no additional peaks, indicating that the diamond is almost not changed after laser interaction. Some parameters did show that the modification of material had occurred and additional peaks in Raman spectra (typical for low-quality chemical vapor deposition CVD diamond) appeared, indicating the growing disorder of material or manufacturing of the new carbon phase.

Surface Roughness and Morphology Analysis Using an Atomic Force Microscopy of Polycrystalline Diamond Coated Si3N4 Deposited by Microwave Plasma Assisted Chemical Vapor Deposition

2008 ◽  
Vol 136 ◽  
pp. 153-160
Author(s):  
Agung Purniawan ◽  
E. Hamzah ◽  
M.R.M. Toff
Keyword(s):  
Surface Roughness ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Power ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Chamber Pressure ◽  
Diamond Nucleation ◽  
Deposition Parameters

Diamond is the hardest material and has high chemical resistant which is one form of carbon. In the present work a study was carried out on polycrystalline diamond coated Si3N4 substrate. The diamond was deposited by Microwave Plasma Assisted Chemical Vapor Deposition (MPACVD) under varying deposition parameters namely CH4 diluted in H2, microwave power and chamber pressure. SEM and AFM are used to investigate the surface morphology and surface roughness. Nucleation phenomena and crystal width were also studied using AFM. Based on SEM investigation it was found that the chamber pressure and %CH4 have more significant effects on nucleation and facet of polycrystalline diamond, In addition microwave power has an effect on the diamond facet that changed from cubic to cauliflower structure. Surface roughness results show that increasing the %CH4 has decreased surface roughness 334.83 to 269.99 nm at 1 to 3% CH4, respectively. Increasing microwave power leads to increase in diamond nucleation and coalescence which lead to less surface roughness. Increasing gas pressure may eliminate Si contamination however it reduces diamond nucleation.

scholarly journals Isotope Effect in Thermal Conductivity of Polycrystalline CVD-Diamond: Experiment and Theory

Crystals ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 322
Author(s):  
Alexander V. Inyushkin ◽  
Alexander N. Taldenkov ◽  
Victor G. Ralchenko ◽  
Andrey P. Bolshakov ◽  
Alexander V. Khomich
Keyword(s):  
Thermal Conductivity ◽  
Chemical Vapor Deposition ◽  
Isotopic Composition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Chemical Vapor ◽  
Polycrystalline Diamond ◽  
Cvd Diamond ◽  
Plasma Chemical Vapor Deposition

We measured the thermal conductivity κ(T) of polycrystalline diamond with natural (natC) and isotopically enriched (12C content up to 99.96 at.%) compositions over a broad temperature T range, from 5 to 410 K. The high quality polycrystalline diamond wafers were produced by microwave plasma chemical vapor deposition in CH4-H2 mixtures. The thermal conductivity of 12C diamond along the wafer, as precisely determined using a steady-state longitudinal heat flow method, exceeds much that of the natC sample at T>60 K. The enriched sample demonstrates the value of κ(298K)=25.1±0.5 W cm−1 K−1 that is higher than the ever reported conductivity of natural and synthetic single crystalline diamonds with natural isotopic composition. A phenomenological theoretical model based on the full version of Callaway theory of thermal conductivity is developed which provides a good approximation of the experimental data. The role of different resistive scattering processes, including due to minor isotope 13C atoms, defects, and grain boundaries, is estimated from the data analysis. The model predicts about a 37% increase of thermal conductivity for impurity and dislocation free polycrystalline chemical vapor deposition (CVD)-diamond with the 12C-enriched isotopic composition at room temperature.

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