• Proceedings of the Optical Society of Korea Conference
• /
• 1997.08a
• /
• pp.17-17
• /
• 1997

• Journal of the Korean Vacuum Society
• /
• v.17 no.3
• /
• pp.204-210
• /
• 2008

ZnO thin films were grown on a glass by RF sputtering system with RF power 100W and oxygen partial pressure of $0%{/sim}30%$. Elliptic constants were measured by using a phase modulated spectroscopic ellipsometer and analyzed with the Tauc-Lorentz dispersion formula and best fit method in the range of 1.5 to 3.8eV. Also, scanning electron microscope(SEM) was used for the analysis of surface crystallization condition. From elliptic constants spectra, optical constants, thickness and roughness of ZnO films were evaluated. Total thickness of ZnO films obtained by ellipsometry showed good agreement with SEM data. It was found that the grain size of the films were getting smaller with increasing oxygen partial pressure. Band-gap of ZnO films increase with the oxygen partial pressure. These findings clearly indicate that optical properties of ZnO films are strongly dependent on the oxygen partial pressure. It could be explained that increasing the oxygen partial pressure induced high crystalline imperfection in the ZnO films.

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

• Journal of the Korean Vacuum Society
• /
• v.17 no.2
• /
• pp.138-147
• /
• 2008

$SiO_2/TiO_2/ZrO_2$ broadband anti-reflective multi-layer thin films were prepared at room temperature by RF sputtering system. Optical constants and structural properties on each layer of films were analyzed by spectroscopic ellipsometer and transmittance spectra of the films were measured by $UV-V_{is}$ spectrophotometer in the range of 300$\sim$900 nm. To evaluate the films, we compared the measured and analyzed spectra with designed spectra. We investigated influence of discrepancy of thickness and refractive indices of each layer on changes of the transmittance spectra. It was found that refractive indices and shape of dispersion of deposition materials are more contributed to changes of the transmittance spectra than thickness of layer.

• Proceedings of the Optical Society of Korea Conference
• /
• 2005.02a
• /
• pp.76-77
• /
• 2005

• Proceedings of the Optical Society of Korea Conference
• /
• 2004.07a
• /
• pp.218-219
• /
• 2004

• Journal of the Korean Vacuum Society
• /
• v.4 no.4
• /
• pp.386-393
• /
• 1995

이온주입된 실리콘 시료들의 열처리 조건에 따른 재결정화를 분광 타원해석법(Spectroscopic Ellipsometry, SE)을 사용하여 연구하였다. 열처리 후에도 잔류하는 결함들의 양과 분포를 구하기 위한 시료의 층구조 분석에 있어서 손상층의 유효굴절율은 Bruggeman 유효매질이론을 이용하여 구하였으며 기준 비정질실리콘 데이터로서는 완화된 비정질실리콘의 광학상수와 이온주입에 의해서 만들어진 비정질 실리콘의 광학상수를 함께 사용하였다. 조사된 대부분의 열처리 조건하에서 고체상 적층성장(solid-phase epitaxial growth)과정에 따라 비정질층이 재결정화되는 것이 관측되었다.

• Korean Journal of Optics and Photonics
• /
• v.13 no.3
• /
• pp.215-222
• /
• 2002

Using an in-situ ellipsometer, we monitored the growth curve of optical recording media in real time. For confirmation of the thickness control using in-situ ellipsometry, we analyzed the deposited multi-layer sample made of Ge-Sb-Te alloy film and ZnS-Si0$_2$ dielectric films using an exsitu spectroscopic ellipsometer. The target material in the first sputtering gun is ZnS-SiO$_2$ as the protecting dielectric layer and that in the second gun is Ge$_2$sb$_2$Te$_{5}$ as the receding layer. While depositing ZnS-SiO$_2$, Ge$_2$Sb$_2$Te$_{5}$ and ZnS-SiO$_2$ films on c-Si substrate in sequence, we measured Ψ $\Delta$ in real time. Utilizing the complex refractive indices of Ge$_2$Sb$_2$Te$_{5}$ and ZnS-SiO$_2$ obtained from the analysis of spectroscopic ellipsometry data, the evolution of ellipsometric constants Ψ, $\Delta$ with thickness is calculated. By comparing the calculated evolution curve of ellipsometric constants with the measured one, and by analyzing the effect of density variation of the Ge$_2$Sb$_2$Te$_{5}$ recording layer on ellipsometric constants with thickness, we precisely monitored the growth rate of the Ge-Sb-Te multilayer and controlled the growth process. The deviation of the real thicknesses of Ge-Sb-Te multilayer obtained under the strict monitoring is post confirmed to be less than 1.5% from the target structure of ZnS-SiO$_2$(1400 $\AA$)IGST(200 $\AA$)$\mid$ZnS-SiO$_2$(200$\AA$).(200$\AA$).

• Proceedings of the Korean Vacuum Society Conference
• /
• 2012.08a
• /
• pp.167-167
• /
• 2012

Aluminium-zinc-tin oxide (AZTO) 박막 트랜지스터는 Spin-coating 방법으로 제작되었다. AZTO용액의 용매는 2-Methoxyethanol, 용질은 각각 Aluminium nitride, Zinc acetate dihydrate, Tin chloride가 사용되어 제작되었다. 용액의 안정성을 위해서 미량의 Mono ethyl amine이 첨가되었다. 용액의 Zn:Sn의 몰 비율은 1 : 1로 고정 되었으며 Al의 mole비를 다양하게 늘리면서 실험을 진행하였다. 이렇게 만들어진 AZTO용액은 3,000 rpm으로 30초간 Spin-coating하였으며 이후 Furnace system을 통하여 $500^{\circ}C$의 온도로 1시간 동안 후열처리 공정을 진행하였다. AZTO박막을 활성층으로 제작된 박막 트랜지스터는 Al의 비율이 늘어남에 따라 처음엔 이동도가 증가하였으나 이후 이동도가 낮아지며 소자특성이 나빠지는 것을 보였다. 이러한 현상의 원인을 알아보고자 물리적, 전기적, 광학적 분석을 통해서 Al양의 변화가 박막트랜지스터 구동에 미치는 영향을 해석하였다. 먼저 AZTO용액은 열중량측정/시차열분석법(Thermo Gravimetry/Differential Thermal Analysis)을 이용하여 spin-coating 이후 후 열처리 온도 결정 및 박막의 변화를 관찰하였으며, X-선 분광(X-ray photoelectron spectroscopy)을 이용하여 박막의 조성 및 전자구조의 변화를, 타원분광해석법(Spectroscopic Ellipsometry)분석을 통하여 밴드 갭과 전도대 이하 밴드 갭 내에 존재하는 결함상태변화를 관찰하였다. AZTO 박막 내의 Al양을 조절하는 것은 박막내의 에너지 준위의 변화를 야기하고 그로인해 박막트랜지스터의 특성을 변화킨다는 결과를 도출하였다.

• Korean Journal of Optics and Photonics
• /
• v.8 no.1
• /
• pp.31-36
• /
• 1997

We measured refractive indices and thicknesses of SiO$_2$ thin films that have been plated on LCD glass substrate for the purpose of preventing the out-diffusion of sodium ions. The best experimental condition to determine refractive index and thickness of SiO$_2$ thin film by using ellipsometry is searched for, where ⅰ) the film thickness is increased uniformly by 20 $\AA$ from 0 $\AA$ to the period thickness while the angle of incidence is fixed and ⅱ) the angle of incidence is increased uniformly by 1$^{\circ}$ from 45$^{\circ}$ to 70$^{\circ}$ while the film thickness is fixed. We estimated the errors in determining the refractive index and thickness by comparing the measurement error of $\Delta$ and Ψ with the calculated one. The ellipsometric constants of SiO$_2$ thin film on LCD glass substrate are measured at several angle of incidence around the Brewster angle, which is the best angle if the experimental error of ellipsometer is not sensitive to the incident angle. Also the best fit refractive index and thickness of SiO$_2$ thin film to these ellipsometric constants measured at several angle of incidenc eas well as the best fit ones to the SE data are obtained using regressional analysis.