• Korean Chemical Engineering Research
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• 제55권2호
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• pp.275-278
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• 2017

Heterogeneous semiconductor composites have been widely used to establish high-performance microelectronic or optoelectronic devices. During a deposition of silicon atoms on silicon/germanium compound surfaces, germanium (Ge) atoms are segregated from the substrate to the surface and are mixed in incoming a silicon layer. To suppress Ge segregation to obtain the interface sharpness between silicon layers and silicon/germanium composite layers, approaches have used silicon hydride gas species. The hydrogen atoms can play a role of inhibitors of silicon/germanium exchange. However, there are few kinetic models to explain the hydrogen effects. We propose using segregation probability which is affected by hydrogen atoms covering substrate surfaces. We derived the model to predict the segregation probability as well as the profile of Ge fraction through layers by using chemical reactions during silicon deposition.

• Current Photovoltaic Research
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• 제8권1호
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• pp.1-5
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• 2020

The most important factor in enhancing the performance of an optical device is to minimize reflection and increasing transmittance of light for a broad wavelength range. The choice of appropriate coating material is crucial in decreasing reflection losses at the substrate. The purpose of this review is to highlight anti-reflection coating (ARC) materials that can be applied to silicon solar cell and glass substrate for minimizing reflection losses. The optical and electrical behavior of ARC on a substrate is highly dependent on thickness and refractive index (RI) of ARC films that are being deposited on it. The coating techniques and performance of single and multi-layered ARC films after coated on a substrate in a wide range of wavelength spectrum will be studied in the paper.

• ETRI Journal
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• 제28권1호
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• pp.9-16
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• 2006

In this paper, we analyzed and measured the electrical crosstalk characteristics of a 1.25 Gbps triplexer module for Ethernet passive optical networks to realize fiber-tothe-home services. Electrical crosstalk characteristic of the 1.25 Gbps optical triplexer module on a resistive silicon substrate should be more serious than on a dielectric substrate. Consequently, using the finite element method, we analyze the electrical crosstalk phenomena and propose a silicon substrate structure with a dummy ground line that is the simplest low-crosstalk layout configuration in the 1.25 Gbps optical triplexer module. The triplexer module consists of a laser diode as a transmitter, a digital photodetector as a digital data receiver, and an analog photodetector as a cable television signal receiver. According to IEEE 802.3ah and ITU-T G.983.3, the digital receiver and analog receiver sensitivities have to meet -24 dBm at $BER=10^{-12}$ and -7.7 dBm at 44 dB SNR. The electrical crosstalk levels have to maintain less than -86 dB from DC to 3 GHz. From analysis and measurement results, the proposed silicon substrate structure that contains the dummy line with $100\;{\mu}m$ space from the signal lines and 4 mm separations among the devices satisfies the electrical crosstalk level compared to a simple structure. This proposed structure can be easily implemented with design convenience and greatly reduce the silicon substrate size by about 50 %.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.85-88
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• 2004

Mono-crystalline silicon(mono-Si) is both abundant in our environment and an excellent material for Si device applications. However, single crystalline silicon solar cell has been considered to be expensive for terrestrial applications. For that reason, the last few years have seen very rapid progress in the research and development activities of layer transfer(LT) processes. Thin film Si layers which can be detached from a reusable mono-Si wafers served as a substrate for epitaxial growth. The epitaxial films have a very high efficiency potential. LT technology is a promising approach to reduce fabrication cost with high efficiency at large scale since expensive Si substrate can be recycled. Low quality Si can be used as a substrate. Therefore, we propose one of the major technologies on fabricating thin film Si substrate using a LT. In this paper, we study the LT method using the electrochemical etching(ECE) and solid edge.

• 센서학회지
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• 제30권4호
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• pp.267-272
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• 2021

In this study, Ag was deposited to investigate its applicability as a surface-enhanced Raman scattering substrate after forming a grass-type black silicon structure through maskless reactive ion etching. Grass-structured black silicon with heights of 2 - 7 ㎛ was formed at radio-frequency (RF) power of 150 - 170 W. The process pressure was 250 mTorr, the O₂/SF₆ gas ratio was 15/37.5, and the processing time was 10 - 20 min. When the processing time was increased by more than 20 min, the self-masking of Si_xO_yF_z did not occur, and the black silicon structure was therefore not formed. Raman response characteristics were measured based on the Ag thickness deposited on a black silicon substrate. As the Ag thickness increased, the characteristic peak intensity increased. When the Ag thickness deposited on the black silicon substrate increased from 40 to 80 nm, the Raman response intensity at a Raman wavelength of 1507 / cm increased from 8.2 × 10³ to 25 × 10³ cps. When the Ag thickness was 150 nm, the increase declined to 30 × 10³ cps and showed a saturation tendency. When the RF power increased from 150 to 170 W, the response intensity at a 1507/cm Raman wavelength slightly increased from 30 × 10³ to 33 × 10³ cps. However, when the RF power was 200 W, the Raman response intensity decreased significantly to 6.2 × 10³ cps.

• 한국전기전자재료학회논문지
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• 제18권12호
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• pp.1106-1110
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• 2005

We fabricated (110) silicon hard master by using anisotropic wet etching for embossing. The etching chemical for the silicon wafer was a TMAH $25\%$ solution. The anisotropic wet etching produces a smooth sidewall surface and the surface roughness of the fabricated master is about 3 nm. After spin coating an organic-inorganic sol-gel hybrid material on a silicon substrate, we employed hot embossing technique operated at a low pressure and temperature to form patterns on the silicon substrate by using the fabricated master. We successfully fabricated the multi-mode planar optical waveguides showing low propagation loss of 0.4 dB/cm. The surface roughness of embossed patterns was uniform for more than 10 times of the embossing processes with a single hydrophobic surface treatment of the silicon hard master.

• 한국표면공학회지
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• 제32권3호
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• pp.235-238
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• 1999

Silicon dioxide films were prepared by anodizing silicon wafers in an ethylene $glycol+HNO_3(0.04{\;}N)$ at 20 to $70^{\circ}C$. The voltage between silicon anode and platinum cathode was measured during this process. Under the constant current electrolysis, the voltage increased with oxide film growth. The transition time at which the voltage reached the predetermined value depended on the temperature of the electrolyte. After the time of electrolysis reached the transition time, the anodization was changed the constant voltage mode. The depth profile of oxide film/Si substrate was confirmed by XPS analysis to study the influence of the electrolyte temperature on the anodization. Usually, the oxide-silicon peaks disappear in the silicon substrate, however, this peak was not small at $45^{\circ}C$ in this region.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.1315-1318
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• 2004

Nano-scale fabrication of silicon substrate in an aqueous solution based on the use of atomic force microscopy was demonstrated. A specially designed cantilever with diamond tip, allowing the formation of damaged layer on silicon substrate easily by a simple scratching process (Tribo-Nanolithography, TNL), has been applied instead of conventional silicon cantilever for scanning. A slant nanostructure can be fabricated by a process in which a thin damaged layer rapidly forms in the substrate at the diamond tip-sample junction along scanning path of the tip and simultaneously the area uncovered with the damaged layer is being etched. This study demonstrates how the TNL parameters can affect the formation of damaged layer and the shape of 3-D structure, hence introducing a new process of proximal nanolithography in aqueous solution.

• 한국정밀공학회지
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• 제22권2호
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• pp.194-201
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• 2005

Nanoscale fabrication of silicon substrate in an aqueous solution based on the use of atomic force microscopy was demonstrated. A specially designed cantilever with diamond tip, allowing the formation of damaged layer on silicon substrate easily by a simple scratching process (Tribo-Nanolithography, TNL), has been applied instead of conventional silicon cantilever for scanning. A slant nanostructure can be fabricated by a process in which a thin damaged layer rapidly forms in the substrate at the diamond tip-sample junction along scanning path of the tip and simultaneously the area uncovered with the damaged layer is being etched. This study demonstrates how the TNL parameters can affect the formation of damaged layer and the shape of 3-D structure, hence introducing a new process of AFM-based nanolithography in aqueous solution.

• International Journal of Precision Engineering and Manufacturing
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• 제7권4호
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• pp.8-13
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• 2006

Nanoscale fabrication of silicon substrate in an aqueous solution based on the use of atomic force microscopy was demonstrated. A specially designed cantilever with a diamond tip, allowing the formation of a mask layer on the silicon substrate by a simple scratching process (Tribo-Nanolithography, TNL), has been applied instead of the conventional silicon cantilever for scanning. A slant nanostructure can be fabricated by a process in which a thin mask layer rapidly forms on the substrate at the diamond tip-sample junction along scanning path of the tip, and simultaneously, the area uncovered with the mask layer is etched. This study demonstrates how the TNL parameters can affect the formation of the mask layer and the shape of 3-D structure, hence introducing a new process of AFM-based nanolithography in aqueous solution.