• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.123-124
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• 2011

플라즈마 화학적 기상 증착(plasma enhanced chemical vapor deposition)공정 중 NH3 gas flow rate, RF power, SiH4 gas flow rate을 고정시키고 N2O gas flow rate을 0 sccm부터 250 sccm까지 변화시키는 조건 하에 SiON박막을 증착한 후 그 투과율, 굴절률을 측정하고 분석하였다. N2O gas flow rate조건별 시편들은 증착율을 계산하여 350 nm 두께로 동일하게 SiON을 증착하였고, borofloat위에 SiON을 증착한 샘플은 투과율을, 실리콘기판 위에 SiON을 증착한 샘플로는 굴절률을 측정하였다. 투과율의 경우는 UV/Vis spectrometer를 이용해 633 nm, 1550 nm 두 가지 파장 대 모두에서 N2O gas flow rate이 가장 큰 250 sccm일 때 가장 높은 것을 알 수 있었고 N2O gas flow rate이 낮아질수록 투과율 또한 작아지는 경향을 보였다. 굴절률은 ellipsometer를 이용해 측정하였으며 633 nm 파장에서 N2O gas flow rate가 가장 낮은 0 sccm일 때 굴절률이 가장 큰 값을 가지고 N2O gas flow rate이 커질수록 굴절률은 지수함수적으로 감소되었다(n=1.837~1.494). 이는 N2O gas flow rate이 낮을수록 SiN계열에 커질수록 SiO2계열에 가까워지는 현상으로 이해된다. 이러한 실험분석 결과는 향후 실리카 도파로의 설계 및 최적화를 위해 사용될 수 있다.

• Korean Journal of Optics and Photonics
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• v.22 no.4
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• pp.170-178
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• 2011

The spectroscopic ellipsometric constants are analyzed to determine the thickness and the complex refractive index of a film coated on a semi-transparent substrate, with the reflection from the backside of the substrate properly considered. Expressions representing the effect of the backside reflection on ellipsometric constants are derived using the thickness and the complex refractive index of the substrate. The thickness and the complex refractive of an ITO thin film coated on a glass substrate are obtained by using this method. The results agree quite well with the ones obtained by following the conventional modeling procedure where the backside reflection is neglected during ellipsometric measurement and analysis.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.231-231
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• 2013

반사방지막 코팅(Anti-reflection coating)은 태양전지(Solar cell), 발광다이오드(LED) 등의 반사율을 낮추어 효율을 증대시키기 위하여 사용되고 있다. 본 실험에서는 유리 기판 위에 실리콘 타겟을 이용한 Reactive magnetron sputtering 장비를 활용하여, 50~100 mTorr의 높은 공정 압력(High pressure)에서 Ar：O2 유량비를 변화시키며 증착하여 SiO2 반사방지막 코팅층을 형성하였다. Ellipsometer를 이용하여 SiO2 박막층의 굴절률(Refractive index)을 측정한 결과, 공정 압력과 Ar：O2 유량비에 따라 SiO2 박막이 다양한 굴절률을 가지는 것을 확인할 수 있었다. 또한, UV-Vis spectrometer를 이용하여, 190~1,100 nm 파장에서의 반사율(Reflectance)과 투과율(Transmittance)을 측정하여 비교, 분석하였다. 나아가 증착된 SiO2 반사방지막을 비정질 실리콘 박막 태양전지에 적용하여 효율 향상 효과를 실험하였다. 이를 활용하여 낮은 굴절률을 갖는 반사방지용 SiO2 코팅층을 형성하여 태양전지의 광 변환 효율을 상승 시킬 수 있고, 발광다이오드의 광 추출 효율을 증가시킬 있을 것으로 여겨진다.

• Journal of the Korean Institute of Telematics and Electronics A
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• v.29A no.9
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• pp.20-28
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• 1992

Dielectric thin film of N/O ($Si_{3]N_{4}/SiO_{2}$) for high density stacked dynamic-RAM cell was formed by LPCVD and oxidation(dry & pyrogenic oxidation methods) of the top 7nm $Si_{3]N_{4}$ film. The thickness, structure and composition of this film were measured by ellipsometer, high resolution TEM, AES and SIMS. The insulating characteristics(I-V characteristics) were investigated by HP 4145, and the characteristics of TDDB (Time Dependent Dielectric Breakdown) were evaluated by using CCST(Current Constant Stress Time) method. In this experiment, The optimum oxidation condition for preparation of good insulating and TDDB characteristics of N/O film was pyrogenic oxidation at 85$0^{\circ}C$ for 30 minutes. The leakage current was reduced from 400pA to 7.5pA when SiO$_{2}$ film with thickness of 2nm was formed on the top of $Si_{3]N_{4}$ film by the pyrogenic oxidation method.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.11a
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• pp.115-121
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• 2002

In this research we have investigated the characteristics of ultra thin $HfO_2 /SiON$stack structure films using several analytical techniques. SiON layer was thermally grown on standard SCI cleaned silicon wafer at $825^{\circ}C$ for 12sec under $N_2$O ambient. $HfO_2 /SiON$$_4$/$H_2O$ as precursors and $N_2$as a carrier/purge gas. Solid HfCl$_4$was volatilized in a canister kept at $200^{\circ}C$ and carried into the reaction chamber with pure $N_2$carrier gas. $H_2O$ canister was kept at $12^{\circ}C$ and carrier gas was not used. The films were grown on 8-inch (100) p-type Silicon wafer at the $300^{\circ}C$ temperature after standard SCI cleaning, Spectroscopic ellipsometer and TEM were used to investigate the initial growth mechanism, microstructure and thickness. The electrical properties of the film were measured and compared with the physical/chemical properties. The effects of heat treatment was discussed.

• KIEE International Transactions on Electrophysics and Applications
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• v.5C no.3
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• pp.111-114
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• 2005

Organic monolayers were fabricated onto Au(l l l) substrate by self-assembly method using dipyridinium. Also, organic single molecule in the organic monolayers was selected to measure the current-voltage (I-V) curves by using the ultrahigh vacuum scanning tunneling microscopy (UHV-STM). The organic molecule used in the experiment was dipyridinium dithioacetate, which contains thiol functional group and can be self-assembled easily onto Au(l l l) substrate. The concentration of dipyridinium dithioacetate for self-assembly procedure was I [mM/L]. To confirm the formation of self-assembled mono layers (SAMs), the differences of thickness of the self-assembled organic monolayers were observed by using an ellipsometer, and the morphology and I-V curves of the SAMs were investigated by using UHV-STM. The applied voltages were from -2 [V] to +2 [V], temperature was 300 [K]. The vacuum for measuring current of the organic single molecule was 6 $\times$ 10$^{-8}$ [Torr]. As a result, properties of the negative differential resistance (NDR) in constant voltage were found.

• Electrical & Electronic Materials
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• v.10 no.1
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• pp.8-14
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• 1997

The UV/O$_{3}$ dry cleaning has been well known in removing organic molecules. The UV/O$_{3}$ dry cleaning method was performed to clean the Si wafer surfaces and contact holes contaminated by organic molecules such as residual PR. During the cleaning process, the Si surfaces were analyzed with X-ray photoelectron spectroscopy (XPS), atomic force microscope (AFM) and ellipsometer. When the UV/O$_{3}$ dry cleaning at 200'C was performed for 3 minutes, the residual photoresist was almost removed on Si wafer surfaces, but Si surfaces were oxidized. For UV/O$_{3}$ application of contact hole cleaning, the contact string were formed using the equipment of ISRC (Inter-university Semiconductor Research Center). Before Al deposition, UV/O$_{3}$ (at 200.deg. C) dry cleaning was performed for 3 minutes. After metal annealing, the specific contact resistivity was measured. Because UV/O$_{3}$ dry cleaning removed organic contaminants in contact holes, the specific contact resistivity decreased. Each contact hole size was different, but the specific contact resistivities were all much the same. Thus, it is expected that the UV/O$_{3}$ dry cleaning method will be useful method of removal of the organic contaminants at smaller contact hole cleaning.

• Journal of the Korean institute of surface engineering
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• v.28 no.3
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• pp.133-141
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• 1995

The deposition characteristics of diamond films were investigated for three different substrates : Si, Inconel 600 and steel. Diamond films were prepared by microwave plasma CVD method using $CH_4$, $H_2$ and $O_2$ as reaction gases. The deposited films were analyzed with SEM, Raman spectroscopy and ellipsometer. For Si substrate, diamond films were successfully obtained for most of the deposition conditions used in this study. As the $CH_4$ flow rate decreased and the $O_2$ flow rate increased, the quality of the film was improved due to the reduced non-diamond phase in the film. For Inconel 600 substrate, the surface pretreatment with diamond powders was required to deposit a continuous diamond film. The films deposited at temperatures of $600^{\circ}C$ and $700^{\circ}C$ had mainly diamond phase, but they were peeled off locally due to the difference in the thermal expansion coefficient between the substrate and the deposited films. The films deposited at $500^{\circ}C$ and $850^{\circ}C$ had only the graphitic carbon phase. For steel substrate, all of the films deposited had only the graphitie carbon phase. We speculated that the formation of diamond nuclei on the steel substrate was inhibited due to the diffusion of carbon atoms into the steel substrate which has a large amount of carbon solubility.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.9
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• pp.808-811
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• 2008

Optical and mechanical properties of diamond-like carbon (DLC) films synthesized by RF plasma enhanced chemical vapor deposition were investigated as a function the C/H ratio in gas mixture. The C/H ratio was varied from 6 to 10 %, adjusting the amount of $CH_4$ and $H_2$ as the source gas. The optical and mechanical properties of DLC films were characterized by UV spectrometer, Ellipsometer and Nano-indenter. The change of the C/H ratio during synthesis of DLC films had many effects on the growth rate, transmittance, refractive index and hardness. The growth rate of the films increased exponentially with the increase in C/H ratio. The hardness of the films showed the tendency to improve with increasing C/H ratio, whereas the transmittance decreased. The refractive index was varied from 2.03 to 2.17, and these refractive indexes close to 2.0 indicates that it can be applied to Si-based solar cell.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.15 no.1
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• pp.61-66
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• 2002

A method for designing antireflection (AR) and antistatic (AS) coating layer by the use of conducting polymer as an electrically conductive transparent layer is proposed. The conducting AR coating is composed of four-layer with alternating high and low refractive index layer: silicon dioxide (n=1.44) and titanium dioxide (n=2.02) prepared at low temperature by sol-gel method are used as the low and high refractive index layer, respectively. The poly(3,4-ethylenedioxythiophene) which has the surface resistivity of 10$^4$Ω/$\square$ is used as a conductive layer. Optical constant of each ARAS coating layers such as refractive index and optical thickness were measured by 7he spectroscopic ellipsometer and from the measured optical constants the spectral properties such as reflectance and transmittance were simulated in the risible region. The reflectance of ARAS films on glass substrate was below 1 %R and the transmittance was higher than 95 % in the visible wavelength (400-700 nm). The measured AR spectral properties was very similar to its simulated results.