• 한국결정성장학회지
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• 제4권1호
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• pp.71-75
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• 1994

본 연구에서는 (100) 배향된 단결정 실리콘 웨이퍼의 열탄성응력지수, 열응력과 임계소성변형 온도와의 관계를 모사하였다. 열탄성웅력지수는 <110> 방향에서 최대값을, <100> 방향에서 최소값을 보여주었다. 그리고, 열탄성응력지수로 부터 유도된 열응력과 임계 소성변형 온도의 모사로 부터, 실리콘 웨이퍼가 1000K 이상에서 소성변형될 수 있음을 예측할 수 있었다.

• 한국전기전자재료학회논문지
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• 제26권11호
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• pp.841-845
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• 2013

We give a textured front on silicon wafer for high-efficiency solar cells by using micro contact printing method which uses PDMS (polydimethylsiloxane) silicon rubber as a stamp and SAM (self assembled monolayer)s as an ink. A random pyramidal texturing have been widely used for a front-surface texturing in low cost manufacturing line although the cell with random pyramids on front surface shows relatively low efficiency than the cell with inverted pyramids patterned by normal optical lithography. In the past two decades, the micro contact printing has been intensively studied in nano technology field for high resolution patterns on silicon wafer. However, this promising printing technique has surprisingly never applied so far to silicon based solar cell industry despite their simplicity of process and attractive aspects in terms of cost competitiveness. We employ a MHA (16-mercaptohexadecanoic acid) as an ink for Au deposited $SiO_2/Si$ substrate. The $SiO_2$ pattern which is same as the pattern printed by SAM ink on Au surface and later acts as a hard resist for anisotropic silicon etching was made by HF solution, and then inverted pyramidal pattern is formed after anisotropic wet etching. We compare three textured surface with different morphology (random texture, random pyramids and inverted pyramids) and then different geometry of inverted pyramid arrays in terms of reflectivity.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2007년도 춘계학술대회
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• pp.295-298
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• 2007

Reduction of optical losses in crystalline silicon solar cells by surface modification is one of the most important issues of silicon photovoltaics. Porous Si layers on the front surface of textured Si substrates have been investigated with the aim of improving the optical losses of the solar cells, because an anti-reflection coating(ARC) and a surface passivation can be obtained simultaneously in one process. We have demonstrated the feasibility of a very efficient porous Si ARC layer, prepared by a simple, cost effective, electrochemical etching method. Silicon p-type CZ (100) oriented wafers were textured by anisotropic etching in sodium carbonate solution. Then, the porous Si layers were formed by electrochemical etching in HF solutions. After that, the properties of porous Si in terms of morphology, structure and reflectance are summarized. The structure of porous Si layers was investigated with SEM. The formation of a nanoporous Si layer about 100nm thick on the textured silicon wafer result in a reflectance lower than 5% in the wavelength region from 500 to 900nm. Such a surface modification allows improving the Si solar cell characteristics. An efficiency of 13.4% is achieved on a monocrystalline silicon solar cell using the electrochemical technique.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.233-233
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• 2010

It is important to form the n+ emitter layer for generating electric potential collecting EHP(Electron-Hole Pair). In this paper the formation on the n+ emitter layer of silicon wafer has been made with respect to uniformity of shallow diffusion from a liquid source. The starting material was crystalline silicon wafers of resistivity $0.5{\sim}3\{Omega}{\cdot}cm$, p-type, thickness $200{\mu}m$, direction[100]. The formation of n+ emitter layer from the liquid $POCl_3$ source was carried out for $890^{\circ}C$ in an ambient of $N_2:O_2$::10:1 by volume. And than each conditions are pre-deposition and drive-in time. It has been made uniformity of at least. so, the average of sheet resistance was about 0.12%. In this study, sheet resistance was measured by 4-point prove.

• Transactions on Electrical and Electronic Materials
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• 제12권4호
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• pp.156-159
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• 2011

SiNx:H films have been widely used for anti-reflection coatings and passivation for crystalline silicon solar cells. In this study, SiNx:H films were deposited using high frequency (13.56 MHz) direct plasma enhanced chemical vapor deposition, and the optical and passivation properties were investigated. The radio frequency power, the spacing between the showerhead and wafer, the $NH_3/SiH_4$ ratio, the total gas flow, and the $N_2$ gas flow were changed over certain ranges for the film deposition. The thickness uniformity, the refractive index, and the minority carrier lifetime were then measured in order to study the properties of the film. The optimal deposition conditions for application to crystalline Si solar cells are determined from the results of this study.

• 한국태양에너지학회:학술대회논문집
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• 한국태양에너지학회 2009년도 추계학술발표대회 논문집
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• pp.383-387
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• 2009

Multi-crystalline silicon surface etching without grain-boundary delineation is a challenging task for the fabrication of high efficiency solar cell. The use of sodium hydroxide - sodium hypochlorite (NaOH40% + NaOCl 12%) solution for texturing multi-crystalline silicon wafer surface in solar cell fabrication line is reported in this article. in light current-voltage results, the cells etched in NaOH 40% + NaOCl 12% = 1:2 exhibited higher short circuit current and open circuit voltage than those of the cells etched in NaOH 40% + NaOCl 12% = 1:1 solution. we have obtained 15.19% conversion efficiency in large area(156cm2) multi-Si solar cells etched in NaOH 40% + NaOCl 12% = 1:1 solution.

• 비파괴검사학회지
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• 제36권1호
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• pp.1-8
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• 2016

Single crystalline silicon wafers having (100), (110), and (111) directions are employed as specimens for obtaining slowness profiles. Leaky Lamb waves (LLW) from immersed wafers were detected by varying the incident angles of the specimens and rotating the specimens. From an analysis of LLW signals for different propagation directions and phase velocities of each specimen, slowness profiles were obtained, which showed a unique symmetry with different symmetric axes. Slowness profiles were compared with elastic moduli of each wafer. They showed the same symmetries as crystal structures. In addition, slowness profiles showed expected patterns and values that can be inferred from elastic moduli. This implies that slowness profiles can be used to examine crystal structures of anisotropic solids.

• 신재생에너지
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• 제2권2호
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• pp.4-8
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• 2006

Reduction of optical losses in crystalline silicon solar cells by surface modification is one of the most important issues of silicon photovoltaics. Porous Si layers on the front surface of textured Si substrates have been investigated with the aim of improving the optical losses of the solar cells, because an anti-reflection coating and a surface passivation can be obtained simultaneously in one process. We have demonstrated the feasibility of a very efficient porous Si AR layer, prepared by a simple, cost effective, electrochemical etching method. Silicon p-type CZ (100) oriented wafers were textured by anisotropic etching in sodium carbonate solution. Then, the porous Si layer were formed by electrochemical etching in HF solutions. After that, the properties of porous Si in terms of morphology, structure and reflectance are summarized. The surface morphology of porous Si layers were investigated using SEM. The formation of a porous Si layer about $0.1{\mu}m$ thick on the textured silicon wafer result in an effective reflectance coefficient Reff lower than 5% in the wavelength region from 400 to 1000nm. Such a surface modification allows improving the Si solar cell characteristics.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2006년도 춘계학술대회
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• pp.183-186
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• 2006

Reduction of optical losses in crystalline silicon solar cells by surface modification is one of the most important issues of silicon photovoltaics. Porous Si layers on the front surface of textured Si substrates have been investigated with the aim of improving the optical losses of the solar cells, because an anti-reflection coating and a surface passivation can be obtained simultaneously in one process. We have demonstrated the feasibility of a very efficient porous Si AR layer, prepared by a simple, cost effective, electrochemical etching method. Silicon p-type CZ (100) oriented wafers were textured by anisotropic etching in sodium carbonate solution. Then, the porous Si layer were formed by electrochemical etching in HF solutions. After that, the properties of porous Si in terms of morphology, structure and reflectance are summarized. The surface morphology of porous Si layers were investigated using SEM. The formation of a porous Si layer about $0.1{\mu}m$ thick on the textured silicon wafer result in an effective reflectance coefficient $R_{eff}$ lower than 5% in the wavelength region from 400 to 1000nm. Such a surface modification allows improving the Si solar cell characteristics.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2010년도 하계학술대회 논문집
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• pp.365-365
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• 2010

In this paper, silicon nitride thin films with different silane and ammonia gas ratios were deposited and characterized for the antireflection and passivation layer of high efficiency single crystalline silicon solar cells. As the flow rate of the ammonia gas increased, the refractive index decreased and the band gap increased. Consequently, the transmittance increased due to the higher band gap and the decrease of the defect states which existed for the 1.68 and 1.80 eV in the SiNx films. The reduction in the carrier lifetime of the SiNx films deposited by using a higher $NH_3/SiH_4$ flow ratio was caused by the increase of the interface traps and the defect states in/on the interface between the SiNx and the silicon wafer. The silicon and nitrogen rich films are not suitable for generating both higher carrier lifetimes and transmittance. These results indicate that the band gap and the defect states of the SiNx films should be carefully controlled in order to obtain the maximum efficiency for c-Si solar cells.