• 한국세라믹학회지
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• 제31권5호
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• pp.520-528
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• 1994

An investigation was carried out to understand the effect of the amount of free silicon on the tribological properties of Si-SiC. The specimens of dense Si-SiC composites with various amount of free silicon were fabricated in the temperature of 175$0^{\circ}C$ after molding under various pressure. Wear properties were measured by ball-on-plate wear tester under the constant weight of 4 Kgf at constant sliding speed of 500 mm/sec in water. As the result, the Rockwell hardness and fracture strength of Si-SiC composites remained nearly constant up to 16.62 vol% of free silicon in the Si-SiC microstructure. The Si-SiC composites containing the free silicon of 16.62 vol% was considered to be prominent in the tribological properties, which had the friction coefficient of 0.08 and the specific wear rate of 2.4$\times$10-8$\textrm{mm}^2$Kgf-1. The analysis of the wear surface indicated the complicated processes occuring on the surface such as fine polishing, abrasion, microfracture.

• 한국표면공학회지
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• 제47권1호
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• pp.20-24
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• 2014

Joule heat is generated by applying an electric filed to a conductive layer located beneath or above the amorphous silicon film, and is used to raise the temperature of the silicon film to crystallization temperature. An electric field was applied to an indium tin oxide (ITO) conductive layer to induce Joule heating in order to carry out the crystallization of amorphous silicon. Polycrystalline silicon was produced within the range of a millisecond. To investigate the kinetics of Joule-heating induced crystallization (JIC) solid phase crystallization was conducted using amorphous silicon films deposited by plasma enhanced chemical vapor deposition and using tube furnace in nitrogen ambient. Microscopic and macroscopic uniformity of crystallinity of JIC poly-Si was measured to have better uniformity compared to that of poly-Si produced by other methods such as metal induced crystallization and Excimer laser crystallization.

• 통합자연과학논문집
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• 제7권4호
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• pp.221-226
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• 2014

Optically encoded porous silicon smart particles were successfully fabricated from the free-standing porous silicon thin films using ultrasono-method. DBR PSi was prepared by an electrochemical etch of heavily doped $p^{{+}{+}}$-type silicon wafer. DBR PSi was prepared by using a periodic pseudo-square wave current. The surface-modified DBR PSi was prepared by either thermal oxidation or thermal hydrosilylation. Free-standing DBR PSi films were generated by lift-off from the silicon wafer substrate using an electropolishing current. Free-standing DBR PSi films were ultrasonicated to create DBR-structured porous smart particles. Optical characteristics of porous smart particles were measured by FT-IR spectroscopy. The surface morphology of porous smart particles was determined by FE-SEM.

• 한국결정성장학회지
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• 제26권5호
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• pp.171-174
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• 2016

The diamond wire sawing method to produce silicon wafers for the photovoltaic application is still a new and highly investigated wafering technology. This technology, featured as the higher productivity, lower wear of the wire, and easier recycling of the coolant, is expected to become the mainstream technique for slicing the silicon crystals. However, the saw marks on the wafer surface have to be investigated and improved. This paper discusses the removal of saw marks on diamond wire-sawn single crystalline silicon wafer. With a pretreatment step using tetramethyl ammonium hydroxide ($(CH_3)_4NOH$, TMAH) and conventional texturing process with KOH solution (1 % KOH, 8 % IPA, and DI water), the saw marks on the surface of the diamond wire-sawn silicon wafers can be effectively removed and they are invisible to naked eyes completely.

• Transactions on Electrical and Electronic Materials
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• 제4권4호
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• pp.22-25
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• 2003

High series resistance due to the presence of glass frit is one of the major problems for screen printed silicon solar cells. Cells having electrical parameters below the prescribed values are usually rejected during solar module fabrication. Therefore, it is highly desirable to improve the electrical parameters of the silicon solar cells and thereby to increase the overall production yield. It was observed that, the performance of low quality mono-crystalline silicon solar cells made by standard screen printing technology could be improved remarkably by novel surface treatment. We have chemically treated the surface using sodium hydroxide (NaOH) and silver nitrate ($AgNO_3$) solutions. NaOH treatment helps to reduce the series resistance by decreasing the presence of excess glass frit on the top silver grid contact. The $AgNO_3$ treatment is used to reduce the series resistance comes from the deposition of silver on the grids by filling the holes present (if any) within the grid pattern.

• 열처리공학회지
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• 제23권2호
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• pp.83-89
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• 2010

Diamond-like carbon (DLC) coating was studied to be a good tribological problem-solver due to its low friction characteristics and high hardness. However, generally hydrogenated DLC film has shown a weak thermal stability above $300^{\circ}C$. However, the silicon doping DLC process by DC pulse plasma enhanced chemical vapor deposition (PECVD) for the new DLC coating which has a good characterization with thermal stability at high temperature itself has been observed. And we were discussed a process for optimizing silicon content to promote a good thermal stability using various tetramethylsilane (TMS) and methane gas at high-temperature. The chemical compositions of silicon-containing DLC film was analyzed using X-ray photoelectron spectroscopy (XPS) before and after heat treatment. Raman spectrum analysis showed the changed structure on the surface after the high-temperature exposure testing. In particular, the hardness of silicon-containing DLC film showed different values before and after the annealing treatment.

• 한국표면공학회지
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• 제29권6호
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• pp.816-823
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• 1996

Chlorine containing high density plasmas are widely used to etch various materials in the microelectronic device fabrication. In this study, the characteristics of inductively coupled $Cl_2(O_2/N_2$) plasmas and their effects on the formation of silicon etching have been investigated using a Langmuir probe, quadrupole mass spectrometry(QMS), X-ray photoelectron spectroscopy(XPS), and Scanning Electron Microscopy(SEM). The addition of oxygen for chlorine plasmas reduced ion current densities and chlorine radical densities compared to the nitrogen addition by the recombination of oxygen with chlorine. Also, when silicon is etched in $Cl_2/O_2$ plasmas, etch products recombined with oxygen such as $SiCl_xO_y$ emerged. However, when nitrogen is added to chlorine, etch products recombined with nitrogen or Si-N bondings on the etched silicon surface were not found. All the silicon etch characteristics were dependent on the plasma conditions such as ion density, radical density, etc. As a result sub micron vertical silicon trench etch profiles could be effectively formed using optimized etch conditions for $Cl_2/O_2\; and \;Cl_2/N_2$ gas combinations.

• 반도체디스플레이기술학회지
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• 제13권3호
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• pp.21-25
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• 2014

The texturing is one of the most important processes for high efficiency crystalline silicon solar cells. The rear side flatness of silicon solar cell is very important for increasing the light reflectance and forming uniform back surface field(BSF) region in manufacturing high efficiency crystalline silicon solar cells. We investigated texturing difference between front and rear side of wafer by texturing of two adhered wafers. As a result, the flatter rear side was obtained by forming less pyramid size compared to the front side and improved reflectance of long wavelength and back surface field(BSF) region were also achieved. Therefore, the texturing of two adhered wafers can be expected to improve the efficiency of silicon solar cells due to increased short circuit current(Isc).

• Transactions on Electrical and Electronic Materials
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• 제4권5호
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• pp.10-14
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• 2003

A low-cost, large area, random, maskless texturing scheme independent of crystal orientation is expected to have significant impact on terrestrial photovoltaic technology. We investigated silicon surface microstructures formed by reactive ion etching (R IE) in Multi-Hollow cathode system. Desirable texturing effect has been achieved when radio-frequency (rf) power of about 20 Watt per one hollow cathode glow is applied for our RF Multi -Hollow cathode system. The black silicon etched surface shows almost zero reflectance in the visible region as well as in near IR region. The etched silicon surface is covered by columnar microstructures with diameters from 50 to 100 nm and depth of about 500 nm. We have successfully achieved 11.7 % efficiency of mono-crystalline silicon solar cell and 10.2 % for multi-crystalline silicon solar cell.

• 한국표면공학회지
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• 제55권3호
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• pp.143-155
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• 2022

Ceramic oxide layers successfully were formed on the surface of cast Al alloys with high Si contents using plasma electrolytic oxidation (PEO) process in electrolytes containing Na₂SiO₃, NaOH, and additives. The microstructure of the oxide layers was systematically analyzed using scanning electron microscopy (SEM), cross-sectional transmission electron microscopy (TEM), X-ray diffraction patterns (XRD), and energy X-ray dispersive spectroscopy (EDS). XRD analysis indicated that the PEO untreated high-silicon Al alloys (i.e., 17.1 and 11.7 wt.% Si) consist of Al, Si and Al₂Cu phases whereas Al₂Cu phase selectively disappeared after PEO treatment. PEO process yielded an amorphous oxide layer with few second phases including γ-Al₂O₃ and Fe-rich phases. The corrosion behaviors of high-silicon Al alloys treated by PEO process were investigated using electrochemical impedance spectroscopy (EIS) and other electrochemical techniques (i.e., open circuit potential and polarization curve). Electroanalytical studies indicated that high-silicon Al alloys treated by PEO process have greater corrosion resistance than high-silicon alloys untreated by PEO process.