• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.957-961
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• 2004

In order to realize high performance thin film transistor (TFT) on plastic substrate, Si film was deposited on plastic substrate at 170$^{\circ}C$ by using inductivity coupled plasma chemical vapor deposition (ICPCVD). Hydrogen concentration in as-deposited Si film was 3.8% which is much lower than that in film prepared by using conventional plasma enhanced chemical vapor deposition (PECVD). Si film was deposited as micro crystalline phase rather than amorphous phase even at 170$^{\circ}C$ because of high density plasma. By step-by-step Excimer laser annealing, dehydrogenation and recrystallization of Si film were carried out simultaneously. With step-by-step annealing and optimization of underlayer structure, it has succeeded to achieve large grain size of 300nm by using ICPCVD. Base on these results, poly-Si TFT was fabricated on plastic substrate successfully, and it is sufficient to drive pixels of OLEDs, as well as LCDs.

• 한국태양에너지학회:학술대회논문집
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• 2009.11a
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• pp.367-370
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• 2009

It is important to reduce a reflection of light as a solar cell is device that directly converts the energy of solar radiation to electrical energy in oder to improve efficiency of solar cells. The antireflection coating has proven effective in providing substantial increase in solar cell efficiency. This paper investigates the formation of thin film PSi(porous silicon) layer on the surface of crystalline silicon substrates without other ARC(antirefiection coating) layers. On the other hand the formation of $SO_{2}/SiN_x$ ARC layers on the surface of crystalline silicon substrates. After that, the structure of PSi and $SO_2/SiN_x$ ARC was investigated by SEM and reflectance. The formation of PSi layer and $SO_{2}/SiN_x$ ARC layers on the textured silicon wafer result about 5% in the wavelength region from 0.4 to $1.0{\mu}m$. It is achieved on the textured crystalline silicon solar cell that each efficiency is 14.43%, 16.01%.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.632-635
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• 2001

Microcrystalline Si films have been deposited by using five W-wire filaments of 0.5 mm diameter for hot-wire chemical vapor deposition (HWCVD). We compared the HWCVD grown films with the film exposed to transformer couple plasma system for the modification of seed layer. W-wire filament temperature was maintained below 1600$^{\circ}C$ to avoid metal contamination by thermal evaporation at the filament. Deposition conditions were varied with H$_2$dilution ratio, with and without plasma treatment. From the Raman spectra analysis, we observed that the film crystallization was strongly influenced by the H$_2$dilution ratio and weakly depended on the distance between the wire and a substrate. We were able to achieve the crystalline volume fraction of about 70% with an SiH$_4$/H$_2$ratio of 1.3%, a wire temperature of 1514$^{\circ}C$, a substrate separation distance of 4cm, and a chamber pressure of 38 mTorr. We investigated the influence of ${\mu}$c-Si film properties by using a plasma treatment. This article also deals with the influence of the H$_2$dilution ratio in crystallization modification.

• Korean Journal of Materials Research
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• v.10 no.9
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• pp.648-655
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• 2000

Synthesis of the crystalline film was investigated under the diamond growth condition with altering the addition of the nitrogen from 0% to 95%. With increasing the nitrogen concentration, surface morphology of the film was changed from the diamond film with {100} growth plane to the non-faceted diamond film with nano-scale grains. It also showed that the deposition of the diamond film could be synthesized using only methane and nitrogen gases without hydrogen gas. Separated particles with diamond structure showed an octahedral shaped I the nitrogen ranges between 30% and 80%, and newly formed hexagonal crystals are observed when substrate temperature with diamond structure, however, also identify that the hexagonal crystal was SiCN composite composed of Si, C and N atoms.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.100-103
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• 2001

In order to investigate the magnetic properties of CoCr-based bilayered thin films on kind of underlayer, we introduced amorphous Si layer to Co-Cr(-Ta) magnetic layer as underlayer. With the thickness of CoCr, CoCrTa single layer, crystalline orientation and perpendicular coercivity was improved. It was revealed that by introducing the Si underlayer, the c-axis orientation of CoCr, CoCrTa magnetic layer was improved largely. However, with increasing Si film thickness, perpendicular coercivity and saturation magnetization of Cocr/si, CoCrTa/Si bilayered thin films was decreased. Grain size of bilayered thin films became larger.

• Journal of the Korean Ceramic Society
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• v.26 no.3
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• pp.390-394
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• 1989

The stored elastic strain energy due to the thermal expansion mismatch between the thermally oxidized crystalline layer (cristobalite) and CVD Si3N4($\alpha$-Si3N4) on cooling form high oxidation temperature (1000-140$0^{\circ}C$) to room temperature, releases through the crazing of film and lifting at the SiO2/Si3N4 interface. The ratial equation (1/n) which corresponds to the ratio of the relaxation of the stored elastic stain energy due to crazing of film to the total energy, is derived under the assumption of the square crazed pattern, as follow. 1/n={8${\gamma}$(1-v)2}/(ΔL2dE) The ratial equation suggests the reason for the lifting at the SiO2/Si3N4 interface which was observed in this research.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.129-134
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• 2004

The development of fabrication processes of polycrystalline-silicon-thin-film transistors (poly-Si TFTs) at low temperatures is reviewed. Rapid crystallization through laser-induced melt-regrowth has an advantage of formation of crystalline silicon films at a low thermal budget. Solid phase crystallization techniques have also been improved for low temperature processing. Passivation of $SiO_2$/Si interface and grain boundaries is important to achieve high carrier transport properties. Oxygen plasma and $H_2O$ vapor heat treatments are proposed for effective reduction of the density of defect states. TFTs with high performance is reported.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.63 no.2
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• pp.250-256
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• 2014

In this study, we deposited and investigated ${\mu}c$-Si:H thin films prepared by Plasma Enhanced Chemical Vapor Deposition(PECVD) system. To deposition silicon thin films, we controlled $SiH_4$ gas concentration, RF input power, and heater temperature. According to the experiments, the more $SiH_4$ gas concentration increased, deposition rate also increased but crystalline property decreased at the same conditions. In the RF input power case, deposition rate and crystalline property increased together when the input power increased from 100[W] to 300[W]. If RF input power was 300[W], deposition rate has reached saturation point. In the heater temperature, deposition rate increased when heater temperature increased. Crystalline property maintained a certain level until heater temperature was $250[^{\circ}C]$. And then it was a suddenly increased. Multistep method has been proposed to improve the quality of ${\mu}c$-Si:H thin film. $SiH_4$ gas was injected with a time interval. According to the experiments, crystallite ratio improve about 20~60[%] and photo conductivity increased up to six times.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.55 no.12
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• pp.565-569
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• 2006

Plasma enhanced chemical vapor deposition(PECVD) is a well established technique for the deposition of hydrogenated film of silicon nitride (SiNx:H), which is commonly used as an antireflection coating as well as passivating layer in crystalline silicon solar cell. PECVD-SiNx:H films were investigated by varying the deposition and annealing conditions to optimize for the application in silicon solar cells. By varying the gas ratio (ammonia to silane), the silicon nitride films of refractive indices 1.85 - 2.45 were obtained. The film deposited at $450^{\circ}C$ showed the best carrier lifetime through the film deposition rate was not encouraging. The film deposited with the gas ratio of 0.57 showed the best carrier lifetime after annealing at a temperature of $800^{\circ}C$. The single crystalline silicon solar cells fabricated in conventional industrial production line applying the optimized film deposition and annealing conditions on large area substrate of size $125mm{\times}125mm$ (pseudo square) was found to have the conversion efficiencies as high as 17.05 %. Low cost and high efficiency silicon solar cells fabrication sequence has also been explained in this paper.

• Journal of Ceramic Processing Research
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• v.13 no.spc2
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• pp.373-376
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• 2012

Thin films of Ag-SiO2-TiO2 composite oxides with SiO2/TiO2 of 20/80 molar compositions were prepared by the sol-gel method, using tetraethylorthosilicate (TEOS) and titanium isopropoxide (TIP) as precursors. Ag-SiO2-TiO2 films coated on commercial glass substrates have successfully been synthesized using sol-gel method. The Ag-SiO2-TiO2 film with 0.5% Ag-added concentration and 20 mol% SiO2-mixture gives optimal results on crystalline structure, optical property, surface area, and photochromic property. Absorption near the wavelength of the incident light decreased gradually. The reversibility of the two-photon writing process in Ag-SiO2-TiO2 film is clearly seen.