Enhanced Wettability of Nanocrystalline Diamond Films for Biocoating Applications

2012 ◽  
Vol 1395 ◽  
Author(s):  
Jason H. C. Yang ◽  
Kungen Teii
Keyword(s):  
Contact Angle ◽  
Plasma Treatment ◽  
Oxygen Plasma ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Film Surface ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Polar Component ◽  
Oxygen Plasma Treatment

ABSTRACTNanocrystalline diamond (NCD) films are prepared from Ar-rich/N2/CH4 and Ar-rich/H2/CH4 mixtures by microwave plasma-enhanced chemical vapor deposition, and further treated by microwave hydrogen and oxygen plasma exposures separately to enhance the wetting property. The hydrogen plasma treatment has small effect on the surface roughness, while the oxygen plasma treatment forms fine protrusions on the film surface. Results show that the wettability of the hydrogen plasma treated NCD film is nearly constant or little improvement as the polar component of the apparent surface free energy is close to the as-deposit NCD film. In contrast, the wettability of the oxygen plasma treated NCD film is improved dramatically such that the contact angle is reduced from 92º and 4.7º to almost 0º for water and 1-bromonaphthalene, respectively, and the polar component increases significantly to 34 mJ/m2. The low contact angle suggests that the film is considerably a cell adhesive friendly surface, which is essential in maintaining multicellular structure, and thus making it a favorable wetting surface for biological and biomedical applications.

High Breakdown Voltage GaN HEMT Device Fabricated on Self-Standing GaN Substrate

2013 ◽  
Vol 347-350 ◽  
pp. 1535-1539
Author(s):  
Jian Jun Zhou ◽  
Liang Li ◽  
Hai Yan Lu ◽  
Ceng Kong ◽  
Yue Chan Kong ◽  
...  
Keyword(s):  
Plasma Treatment ◽  
Breakdown Voltage ◽  
Oxygen Plasma ◽  
Cutoff Frequency ◽  
Chemical Vapor ◽  
Current Gain ◽  
Organic Chemical ◽  
Oxygen Plasma Treatment ◽  
Gan Hemt ◽  
High Breakdown Voltage

In this letter, a high breakdown voltage GaN HEMT device fabricated on semi-insulating self-standing GaN substrate is presented. High quality AlGaN/GaN epilayer was grown on self-standing GaN substrate by metal organic chemical vapor deposition. A 0.8μm gate length GaN HEMT device was fabricated with oxygen plasma treatment. By using oxygen plasma treatment, gate forward working voltage is increased, and a breakdown voltage of more than 170V is demonstrated. The measured maximum drain current of the device is larger than 700 mA/mm at 4V gate bias voltage. The maximum transconductance of the device is 162 mS/mm. In addition, high frequency performance of the GaN HEMT device is also obtained. The current gain cutoff frequency and power gain cutoff frequency are 19.7 GHz and 32.8 GHz, respectively. A high fT-LG product of 15.76 GHzμm indicating that homoepitaxy technology is helpful to improve the frequency performance of the device.

scholarly journals Influence of Oxygen–Plasma Treatment on In-Situ SiN/AlGaN/GaN MOSHEMT with PECVD SiO2 Gate Insulator

Materials ◽  
2019 ◽  
Vol 12 (23) ◽  
pp. 3968
Author(s):  
Cho ◽  
Cha ◽  
Kim
Keyword(s):  
Plasma Treatment ◽  
Oxygen Plasma ◽  
Surface Condition ◽  
Chemical Vapor ◽  
High Electron Mobility Transistor ◽  
Gate Insulator ◽  
Oxygen Plasma Treatment ◽  
High Electron ◽  
Threshold Voltage Shift

The influence of oxygen–plasma treatment on in situ SiN/AlGaN/GaN MOS high electron mobility transistor with SiO2 gate insulator was investigated. Oxygen–plasma treatment was performed on in situ SiN, before SiO2 gate insulator was deposited by plasma-enhanced chemical vapor deposition (PECVD). DC I-V characteristics were not changed by oxygen plasma treatment. However, pulsed I-V characteristics were improved, showing less dispersion compared to non-treated devices. During short-term gate bias stress, the threshold voltage shift was also smaller in a treated device than in an untreated one. X-ray photoemission spectroscopy also revealed that SiO2 on in situ SiN with oxygen–plasma treatment has an O/Si ratio close to the theoretical value. This suggests that the oxygen plasma treatment-modified surface condition of the SiN layer is favorable to SiO2 formation by PECVD.

Control of Threshold Voltage on the Excimer Laser Annealed Poly-Si Tfts by Oxygen Plasma Treatment on Poly-Si Surface

1995 ◽  
Vol 397 ◽  
Author(s):  
Jae-Ik Woo ◽  
Sang-Gul Lee ◽  
Dae-Gyu Moon ◽  
Chan-Hee Hong ◽  
Hoe-Sup Soh
Keyword(s):  
Plasma Treatment ◽  
Excimer Laser ◽  
Threshold Voltage ◽  
Oxygen Plasma ◽  
Treatment Time ◽  
Chemical Vapor ◽  
Gate Insulator ◽  
Oxygen Plasma Treatment ◽  
Oxide Deposition ◽  
Pressure Chemical

ABSTRACTOxygen plasma treatment was performed on the excimer laser annealed poly-Si surface, followed by gate oxide deposition with low pressure chemical vapor deposition (LPCVD) in order to control the threshold voltage of excimer laser annealed poly-Si thin film transistors (TFTs).Threshold voltages of n-channel TFTs increase from 0.4 to 2.8 V by varying the treatment time from 0 to 7 min. It is shown the effective charge density increased toward negative direction with increase of the treatment time.In addition to the increase of threshold voltage, the oxygen plasma treatment on the Si surface led to an increase in the deposition rate of LPCVD oxide films with an apparent reduction of carbon around the interface between gate insulator and poly-Si film after oxygen plasma treatment.

scholarly journals Hydrophobic modification of bacterial cellulose using oxygen plasma treatment and chemical vapor deposition

Cellulose ◽  
2020 ◽  
Vol 27 (18) ◽  
pp. 10733-10746 ◽  
Author(s):  
Salomé Leal ◽  
Cecília Cristelo ◽  
Sara Silvestre ◽  
Elvira Fortunato ◽  
Aureliana Sousa ◽  
...  
Keyword(s):  
Chemical Vapor Deposition ◽  
Plasma Treatment ◽  
Bacterial Cellulose ◽  
Vapor Deposition ◽  
Oxygen Plasma ◽  
Chemical Vapor ◽  
Oxygen Plasma Treatment ◽  
Hydrophobic Modification

(110)-oriented diamond films synthesized by microwave chemical-vapor deposition

1990 ◽  
Vol 5 (11) ◽  
pp. 2469-2482 ◽  
Author(s):  
Koji Kobashi ◽  
Kozo Nishimura ◽  
Koichi Miyata ◽  
Kazuo Kumagai ◽  
Akimitsu Nakaue
Keyword(s):  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Microwave Plasma ◽  
Hydrogen Plasma ◽  
Diamond Films ◽  
Film Surface ◽  
Chemical Vapor ◽  
Hydrogen Gas ◽  
X Ray ◽  
Bilayer Films

Bilayer diamond films were deposited on Si substrates by microwave-plasma chemical-vapor deposition (CVD) using a methane-hydrogen gas mixture. The first layer was deposited for 3 h using a reaction gas which was composed of 2.5 vol. % methane and 97.5 vol.% hydrogen. The deposited film consisted of very weakly (110)-oriented microcrystalline diamonds as well as amorphous carbon and graphite. In order to remove non-diamond carbons from the film surface, the specimen was treated in hydrogen plasma for 1 h. Finally, a second layer was deposited on the first layer for 14 h using a methane concentration of between 0.2 and 1.6 vol.%. It was found that the x-ray intensity of the (220) diffraction of the bilayer films was much greater than that of the (111) diffraction, indicating that the diamond grains in the second layer were strongly oriented with their crystallographic (110) planes parallel to the substrate surface. X-ray diffraction spectra of bilayer films in which the second layer was deposited for 7, 14, 21, and 35 h using two different methane concentrations, 0.3 and 1.2 vol.%, showed that within periods of up to 21 h, the (220) intensity increased with the deposition time much more quickly than the (111) intensity, indicating that the degree of (110) orientation was further enhanced as the second layer thickness increased. However, the (220) intensity decreased after 21 h, presumably due to thermal randomization. Results of scanning electron microscopy, electron diffraction, and Raman spectroscopy of the bilayer films are also presented.

scholarly journals Shear Bond Strength of Ceramic Veneers to Zirconia–Calcium Silicate Cores

Coatings ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1326
Author(s):  
Ting-Yi Chiang ◽  
Chun-Chuan Yang ◽  
Yi-Hsuan Chen ◽  
Min Yan ◽  
Shinn-Jyh Ding
Keyword(s):  
Contact Angle ◽  
Phase Composition ◽  
Surface Morphology ◽  
Bond Strength ◽  
Plasma Treatment ◽  
Calcium Silicate ◽  
Shear Bond Strength ◽  
Oxygen Plasma ◽  
Oxygen Plasma Treatment ◽  
Water Contact

Improving the bond strength of veneering ceramics to ZrO2-based cores remains a challenge. The purpose of this study was to evaluate the shear bond strength of different ZrO2 cores containing calcium silicate (CaSi) to veneering ceramics. Five types of ZrO2-based cores (n = 230) were divided into two groups: with or without oxygen plasma treatment. These were bound to two veneering ceramics (IPS e.max Ceram or VITA VM9). Shear bond strength of veneering ceramics to various cores was measured (n = 10), in addition to phase composition, surface morphology and contact angle of the cores. The results indicated that the plasma treatment had a significant effect on the water contact angle of the ZrO2-based cores, but had little effect on the bond strength. Regardless of plasma treatment, the highest strength value was recorded in the ZrO2 core specimen containing 20 wt % CaSi, when all cores were adhered to VITA VM 9 veneer. When using IPS e.max Ceram veneer, the shear bond strength of the plasma-treated 20 wt % CaSi-containing ZrO2 core was 16.6 ± 0.9 MPa higher than that of VITA In-Ceram YZ core control (13.4 ± 1.0 MPa) (p < 0.05). We conclude that the presence of 20 wt % CaSi in ZrO2 can improve the shear bond strength of zirconia-based cores to veneering ceramic.

Surface Hydrophilicity Improvement of RGP Contact Lens Material by Oxygen Plasma Treatment

2009 ◽  
Vol 610-613 ◽  
pp. 1268-1272 ◽  
Author(s):  
Shi Heng Yin ◽  
Ying Jun Wang ◽  
Li Ren ◽  
Lian Na Zhao ◽  
Hao Chen ◽  
...  
Keyword(s):  
Contact Angle ◽  
Plasma Treatment ◽  
Contact Lens ◽  
Oxygen Plasma ◽  
Contact Angle Measurement ◽  
Angle Measurement ◽  
Material Surface ◽  
Oxygen Plasma Treatment ◽  
Surface Hydrophilicity ◽  
Lens Material

Oxygen plasma was employed to treat a fluorosilicone acrylate RGP contact lens material (Boston EO) in order to improve surface hydrophilicity. X-ray photoelectron spectroscopy (XPS) was applied to characterize the surface chemical state. The surface morphology and hydrophilicity were investigated by scanning electron microscope (SEM) and contact angle measurement respectively. The surface contact angle measurement indicated an evident improvement of surface hydrophilicity after plasma treatment. XPS results indicated that the incorporation of oxygen and the transform of -Si-CH3 into hydrophilic -Si-O after plasma treatment were the main reasons for surface hydrophilicity improvement. SEM showed some decrease of surface roughness under moderate plasma condition. But plasma with higher power would etch the material surface.

Synthesis and Characterization of Nanocrystalline Diamond and Its Biomedical Application

2004 ◽  
Vol 843 ◽  
Author(s):  
Zhenqing Xu ◽  
Arun Kumar ◽  
Ashok Kumar ◽  
Arun Sikder
Keyword(s):  
Photoelectron Spectroscopy ◽  
Microwave Plasma ◽  
Biomedical Application ◽  
Hydrogen Plasma ◽  
Chemical Properties ◽  
Chemical Vapor ◽  
Nanocrystalline Diamond ◽  
Si Substrates ◽  
Temperature And Pressure

ABSTRACTDiamond is known as the material that has excellent mechanical, electrical and chemical properties. Diamond is also an ideal interface that is compatible with microelectronics process and biological environments to work as a biosensor platform with excellent selectivity and stability. In our study, nanocrystalline diamond (NCD) films were grown on Si substrates by the microwave plasma enhanced chemical vapor deposition (MPECVD) method. Parameters such as gas composition, temperature and pressure are investigated to get the best film quality. Scanning electron microscopy (SEM) and Raman spectroscopy were used to characterize the NCD films. Then the NCD films were treated by hydrogen plasma in the CVD chamber to obtain the hydrogen terminated surface. This hydrogenated NCD film is ready for bio-modification and can work as the platform of the biosensors. Fourier Transform Infrared Spectroscopy (FTIR) and X-ray Photoelectron Spectroscopy (XPS) were employed to confirm the surface hydrogenation.

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