Combination of Plasma Electrolytic Processing and Mechanical Polishing for Single-Crystal 4H-SiC

Single-crystal 4H-SiC is a typical third-generation semiconductor power-device material because of its excellent electronic and thermal properties. A novel polishing technique that combines plasma electrolytic processing and mechanical polishing (PEP-MP) was proposed in order to polish single-crystal 4H-SiC surfaces effectively. In the PEP-MP process, the single-crystal 4H-SiC surface is modified into a soft oxide layer, which is mainly made of SiO2 and a small amount of silicon oxycarbide by plasma electrolytic processing. Then, the modified oxide layer is easily removed by soft abrasives such as CeO2, whose hardness is much lower than that of single-crystal 4H-SiC. Finally a scratch-free and damage-free surface can be obtained. The hardness of the single-crystal 4H-SiC surface is greatly decreased from 2891.03 to 72.61 HV after plasma electrolytic processing. By scanning electron microscopy (SEM) and X-ray Photoelectron Spectroscopy (XPS) observation, the plasma electrolytic processing behaviors of single-crystal 4H-SiC are investigated. The scanning white light interferometer (SWLI) images of 4H-SiC surface processed by PEP-MP for 30 s shows that an ultra-smooth surface is obtained and the surface roughness decreased from Sz 607 nm, Ra 64.5 nm to Sz 60.1 nm, Ra 8.1 nm and the material removal rate (MRR) of PEP-MP is about 21.8 μm/h.

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Ag Nanoparticle-Decorated Oxide Coatings Formed via Plasma Electrolytic Oxidation on ZrNb Alloy

Materials ◽

10.3390/ma12223742 ◽

2019 ◽

Vol 12 (22) ◽

pp. 3742 ◽

Cited By ~ 8

Author(s):

Oleksandr Oleshko ◽

Volodymyr Deineka V ◽

Yevgeniia Husak ◽

Viktoriia Korniienko ◽

Oleg Mishchenko ◽

...

Keyword(s):

Oxide Layer ◽

Photoelectron Spectroscopy ◽

Bacterial Adhesion ◽

Plasma Electrolytic Oxidation ◽

Infectious Complications ◽

Osteoblast Cell ◽

Effective Prevention ◽

X Ray ◽

Electrolytic Oxidation ◽

Plasma Electrolytic

Plasma electrolytic oxidation (PEO) can provide an ideal surface for osteogenic cell attachment and proliferation with further successful osteointegration. However, the same surface is attractive for bacteria due to similar mechanisms of adhesion in prokaryotic and eukaryotic cells. This issue requires the application of additional surface treatments for effective prevention of postoperative infectious complications. In the present work, ZrNb alloy was treated in a Ca-P solution with Ag nanoparticles (AgNPs) for the development of a new oxide layer that hosted osteogenic cells and prevented bacterial adhesion. For the PEO, 0.5 M Ca(H2PO2)2 solution with 264 mg L−1 of round-shaped AgNPs was used. Scanning electron microscopy with energy-dispersive x-ray and x-ray photoelectron spectroscopy were used for morphology and chemical analysis of the obtained samples; the SBF immersion test, bacteria adhesion test, and osteoblast cell culture were used for biological investigation. PEO in a Ca-P bath with AgNPs provides the formation of a mesoporous oxide layer that supports osteoblast cell adhesion and proliferation. Additionally, the obtained surface with incorporated Ag prevents bacterial adhesion in the first 6 h after immersion in a pathogen suspension, which can be an effective approach to prevent infectious complications after implantation.

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Study on the Mechanism of Solid-Phase Oxidant Action in Tribochemical Mechanical Polishing of SiC Single Crystal Substrate

Micromachines ◽

10.3390/mi12121547 ◽

2021 ◽

Vol 12 (12) ◽

pp. 1547

Author(s):

Wanting Qi ◽

Xiaojun Cao ◽

Wen Xiao ◽

Zhankui Wang ◽

Jianxiu Su

Keyword(s):

Single Crystal ◽

Oxide Layer ◽

Material Removal ◽

Solid Phase ◽

Removal Rate ◽

Single Crystal Substrate ◽

Surface Material ◽

Reaction Products ◽

Point Temperature ◽

Crystal Substrate

Na2CO3—1.5 H2O2, KClO3, KMnO4, KIO3, and NaOH were selected for dry polishing tests with a 6H-SiC single crystal substrate on a polyurethane polishing pad. The research results showed that all the solid-phase oxidants, except NaOH, could decompose to produce oxygen under the frictional action. After polishing with the five solid-phase oxidants, oxygen was found on the surface of SiC, indicating that all five solid-phase oxidants can have complex tribochemical reactions with SiC. Their reaction products are mainly SiO2 and (SiO2)x. Under the action of friction, due to the high flash point temperature of the polishing interface, the oxygen generated by the decomposition of the solid-phase oxidant could oxidize the surface of SiC and generate a SiO2 oxide layer on the surface of SiC. On the other hand, SiC reacted with H2O and generated a SiO2 oxide layer on the surface of SiC. After polishing with NaOH, the SiO2 oxide layer and soluble Na2SiO3 could be generated on the SiC surface; therefore, the surface material removal rate (MRR) was the highest, and the surface roughness was the largest, after polishing. The lowest MRR was achieved after the dry polishing of SiC with KClO3.

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Study of Cluster Magnetorheological-Chemical Mechanical Polishing Technology for the Atomic Scale Ultra-Smooth Surface Planarization of SiC

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.797.284 ◽

2013 ◽

Vol 797 ◽

pp. 284-290 ◽

Cited By ~ 4

Author(s):

Jiang Ting Zhu ◽

Jia Bin Lu ◽

Ji Sheng Pan ◽

Qiu Sheng Yan ◽

Xi Peng Xu

Keyword(s):

Material Removal Rate ◽

Chemical Mechanical Polishing ◽

Material Removal ◽

Smooth Surface ◽

Removal Rate ◽

Mechanical Polishing ◽

Atomic Scale ◽

Mechanical Removal ◽

Mr Effect ◽

Sic Wafer

The growth of epitaxial layer of SiC wafer requires the surface of SiC substrate to reach an atomic scale accuracy. To solve the problems of low machining efficiency and low surface accuracy in the polishing process of SiC wafer, a novel ultra-precision machining method based on the synergistic effect of chemical reaction and flexible mechanical removal of the magnetorheological (MR) effect, the MR-chemical mechanical polishing (MRCMP) is proposed. In this technique, magnetic particles, abrasives and chemical additives are used as MR-chemical polishing fluid to form a cluster MR-effect flexible polishing platen under an applied magnetic field, and it is expected to realize an atomic scale ultra-smooth surface planarization with good controllability and high material removal rate by using the flexible polishing platen. Polishing experimental results of C surface of 6H-SiC crystal substrate indicate that an atomic scale zero-defect surface can be obtained. The surface roughness of C surface of SiC wafer decreased from 50.86nm to 0.42nm and the material removal rate was 98nm/min when SiC wafer was polished for 60 minutes.

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Interactions of Ge Atoms with High- ê Oxide Dielectric Surfaces

MRS Proceedings ◽

10.1557/proc-879-z3.23 ◽

2005 ◽

Vol 879 ◽

Cited By ~ 1

Author(s):

Scott K. Stanley ◽

John G. Ekerdt

Keyword(s):

Oxide Layer ◽

Photoelectron Spectroscopy ◽

Chemical Vapor ◽

Temperature Programmed Desorption ◽

Tungsten Filament ◽

X Ray ◽

Dielectric Surfaces ◽

Temperature Programmed ◽

The Stability ◽

Ge Nanocrystals

AbstractGe is deposited on HfO2 surfaces by chemical vapor deposition (CVD) with GeH4. 0.7-1.0 ML GeHx (x = 0-3) is deposited by thermally cracking GeH4 on a hot tungsten filament. Ge oxidation and bonding are studied at 300-1000 K with X-ray photoelectron spectroscopy (XPS). Ge, GeH, GeO, and GeO2 desorption are measured with temperature programmed desorption (TPD) at 400-1000 K. Ge initially reacts with the dielectric forming an oxide layer followed by Ge deposition and formation of nanocrystals in CVD at 870 K. 0.7-1.0 ML GeHx deposited by cracking rapidly forms a contacting oxide layer on HfO2 that is stable from 300-800 K. Ge is fully removed from the HfO2 surface after annealing to 1000 K. These results help explain the stability of Ge nanocrystals in contact with HfO2.

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Growth of sillenite Bi12FeO20 single crystals: structural, thermal, optical, photocatalytic features and first principle calculations

Scientific Reports ◽

10.1038/s41598-020-78598-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Durga Sankar Vavilapalli ◽

Ambrose A. Melvin ◽

F. Bellarmine ◽

Ramanjaneyulu Mannam ◽

Srihari Velaga ◽

...

Keyword(s):

Single Crystal ◽

Single Crystals ◽

Photoelectron Spectroscopy ◽

Diffraction Method ◽

Lattice Parameter ◽

First Principle ◽

X Ray Diffraction ◽

X Ray ◽

First Principle Calculations ◽

Photodegradation Efficiency

AbstractIdeal sillenite type Bi12FeO20 (BFO) micron sized single crystals have been successfully grown via inexpensive hydrothermal method. The refined single crystal X-ray diffraction data reveals cubic Bi12FeO20 structure with single crystal parameters. Occurrence of rare Fe4+ state is identified via X-ray photoelectron spectroscopy (XPS) and X-ray absorption spectroscopy (XAS). The lattice parameter (a) and corresponding molar volume (Vm) of Bi12FeO20 have been measured in the temperature range of 30–700 °C by the X-ray diffraction method. The thermal expansion coefficient (α) 3.93 × 10–5 K−1 was calculated from the measured values of the parameters. Electronic structure and density of states are investigated by first principle calculations. Photoelectrochemical measurements on single crystals with bandgap of 2 eV reveal significant photo response. The photoactivity of as grown crystals were further investigated by degrading organic effluents such as Methylene blue (MB) and Congo red (CR) under natural sunlight. BFO showed photodegradation efficiency about 74.23% and 32.10% for degrading MB and CR respectively. Interesting morphology and microstructure of pointed spearhead like BFO crystals provide a new insight in designing and synthesizing multifunctional single crystals.

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Prediction of the surface roughness and material removal rate in chemical mechanical polishing of single-crystal SiC via a back-propagation neural network

Precision Engineering ◽

10.1016/j.precisioneng.2021.04.012 ◽

2021 ◽

Vol 72 ◽

pp. 102-110

Author(s):

Jiayun Deng ◽

Qixiang Zhang ◽

Jiabin Lu ◽

Qiusheng Yan ◽

Jisheng Pan ◽

...

Keyword(s):

Neural Network ◽

Surface Roughness ◽

Single Crystal ◽

Material Removal Rate ◽

Chemical Mechanical Polishing ◽

Material Removal ◽

Removal Rate ◽

Back Propagation ◽

Back Propagation Neural Network ◽

Single Crystal Sic

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Preparation of Novel Ag–Si–TiO2 Composite and Research on Its Photocatalytic Degradation of Formaldehyde

Science of Advanced Materials ◽

10.1166/sam.2021.3864 ◽

2021 ◽

Vol 13 (3) ◽

pp. 371-380

Author(s):

Yongjun Wu ◽

Nina Xie ◽

Lu Yu

Keyword(s):

Photoelectron Spectroscopy ◽

Removal Rate ◽

Sol Gel ◽

Catalytic Performance ◽

Formaldehyde Concentration ◽

Order Kinetic ◽

Solution Ph ◽

Visible Absorption ◽

X Ray ◽

Co Doped

A novel Ag–Si–TiO2 composite was prepared via sol–gel method for removing residual formaldehyde in shiitake mushroom. The structure of Ag–Si–TiO2 composite was characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS) analyses. Ultraviolet-visible absorption spectroscopy (UV-Vis) and N2 adsorption-desorption tests showed that Ag and Si co-doped decreased the band gap, the Brunauer-Emmett-Teller (BET) specific surface area of the samples increased and the recombination probability of electron-hole pairs (e--h+) reduced. Effect on removal rate of formaldehyde with different Ag-Si co-doped content, formaldehyde concentration and solution pH were investigated, and the results showed that 6.0 wt%Ag-3.0 wt%Si-TiO2 samples had an optimum catalytic performance, and the degradation efficiency reached 96.6% after 40 W 365 nm UV lamp irradiation for 360 min. The kinetics of formaldehyde degradation by Ag–Si–TiO2 composite photocatalyst could be described by Langmuir-Hinshelwood first-order kinetic model.

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29Si NMR and XPS Investigation of the Structure of Silicon Oxycarbide Glasses Derived from Polysiloxane Precursors

MRS Proceedings ◽

10.1557/proc-346-351 ◽

1994 ◽

Vol 346 ◽

Cited By ~ 8

Author(s):

R.J.P. Corriu ◽

D. Leclercq ◽

P.H. Mutin ◽

A. Vioux

Keyword(s):

Solid State ◽

Photoelectron Spectroscopy ◽

Solid State Nmr ◽

Random Distribution ◽

Silicon Oxycarbide ◽

29Si Nmr ◽

Xps Spectra ◽

Excess Carbon ◽

X Ray ◽

Silicon Oxycarbide Glasses

ABSTRACTTwo silicon oxycarbide glasses with different compositions (O/Si ratio 1.2 and 1.8) were prepared by pyrolysis at moderate temperature (900 °C) of polysiloxane precursors. Their structure was investigated using quantitative 29Si solid-state NMR and X-ray photoelectron spectroscopy (XPS). The environment of the silicon atoms in the oxycarbide phase corresponded to a purely random distribution of Si-O and Si-C bonds depending on the O/Si ratio of the glass only and not on the structure of the precursors. At the light of the NMR results, the Si2p XPS spectra of the glasses may be interpreted using the contribution of the five possible SiOxC4-x tetrahedra. The Cls spectra of these glasses indicated the presence of oxycarbide carbon in CSi4 tetrahedra, similar to carbide carbon, and graphitic-like excess carbon.

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Effect of Process Parameters on Material Removal Rate in Chemical Mechanical Polishing of 6H-SiC(0001)

Materials Science Forum ◽

10.4028/www.scientific.net/msf.600-603.831 ◽

2008 ◽

Vol 600-603 ◽

pp. 831-834 ◽

Cited By ~ 9

Author(s):

Joon Ho An ◽

Gi Sub Lee ◽

Won Jae Lee ◽

Byoung Chul Shin ◽

Jung Doo Seo ◽

...

Keyword(s):

Material Removal Rate ◽

Chemical Mechanical Polishing ◽

Material Removal ◽

Colloidal Silica ◽

Removal Rate ◽

Mechanical Polishing ◽

Diamond Particles ◽

Average Grain Size ◽

Silica Slurry ◽

Sic Wafer

2inch 6H-SiC (0001) wafers were sliced from the ingot grown by a conventional physical vapor transport (PVT) method using an abrasive multi-wire saw. While sliced SiC wafers lapped by a slurry with 1~9㎛ diamond particles had a mean height (Ra) value of 40nm, wafers after the final mechanical polishing using the slurry of 0.1㎛ diamond particles exhibited Ra of 4Å. In this study, we focused on investigation into the effect of the slurry type of chemical mechanical polishing (CMP) on the material removal rate of SiC materials and the change in surface roughness by adding abrasives and oxidizer to conventional KOH-based colloidal silica slurry. The nano-sized diamond slurry (average grain size of 25nm) added in KOH-based colloidal silica slurry resulted in a material removal rate (MRR) of 0.07mg/hr and the Ra of 1.811Å. The addition of oxidizer (NaOCl) in the nano-size diamond and KOH based colloidal silica slurry was proven to improve the CMP characteristics for SiC wafer, having a MRR of 0.3mg/hr and Ra of 1.087Å.

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Oxidation of silicon carbide and the formation of silica polymorphs

Journal of Materials Research ◽

10.1557/jmr.2006.0317 ◽

2006 ◽

Vol 21 (10) ◽

pp. 2550-2563 ◽

Cited By ~ 24

Author(s):

Maxime J-F. Guinel ◽

M. Grant Norton

Keyword(s):

Silicon Carbide ◽

Photoelectron Spectroscopy ◽

Polycrystalline Silicon ◽

Ambient Pressure ◽

Silicon Oxycarbide ◽

Oxide Scales ◽

X Ray ◽

Transmission Electron ◽

Polycrystalline Silicon Carbide ◽

Crystalline Films

The oxidation of both single crystal and relatively pure polycrystalline silicon carbide, between 973 and 2053 K, resulted in the formation of cristobalite, quartz, or tridymite, which are the stable crystalline polymorphs of silica (SiO2) at ambient pressure. The oxide scales were found to be pure SiO2 with no contamination resulting from the oxidizing environment. The only variable affecting the occurrence of a specific polymorph was the oxidation temperature. Cristobalite was formed at temperatures ≥1673 K, tridymite between 1073 and 1573 K, and quartz formed at 973 K. The polymorphs were determined using electron diffraction in a transmission electron microscope. These results were further confirmed using infrared and Raman spectroscopies. Cristobalite was observed to grow in a spherulitic fashion from amorphous silica. This was not the case for tridymite and quartz, which appeared to grow as oriented crystalline films. The presence of a thin silicon oxycarbide interlayer was detected at the interface between the SiC substrate and the crystalline silica using x-ray photoelectron spectroscopy.

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