• Proceedings of the Korean Vacuum Society Conference
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• 2008.02a
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• pp.351-351
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• 2008

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

• Proceedings of the Materials Research Society of Korea Conference
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• 1998.11a
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• pp.18-18
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• 1998

(No Abstract.see/full/text)

• Journal of Korean Ophthalmic Optics Society
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• v.12 no.1
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• pp.85-90
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• 2007

We deposited thin films of ZnS(Zinc Sulphide), in which was used antireflection coating material of glasses-lens on silicon and slide-glass substrates using spin coating method, and measured spectra of ellipsometry angles ${\Delta}$ and ${\Psi}$ in the photon-energy range of 1.5~5.0 eV using a variable angle spectroscopic ellipsometer. The optical constants, refractive index and extinction coefficient, of ZnS were determined via the dispersion parameters extracted from the curve-fitting process based on Jellison-Modine dispersion function.

• Journal of the Korean Vacuum Society
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• v.18 no.1
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• pp.60-65
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• 2009

We performed a study on optical properties of $BaSm_2Ti_4O_{12}$ thin films by vacuum ultra violet spectroscopic ellipsometry in the $0.92{\sim}8.6\;eV$ energy range. For the analysis of the measured ellipsometric spectra, a 5-layer model was applied where optical property of the $BaSm_2Ti_4O_{12}$ layer was well represented by a Tauc-Lorentz dispersion function. Our analysis clearly showed new structure in high energy region at about 7.5 eV Consistent changes of refractive index & extinction coefficient of the $BaSm_2Ti_4O_{12}$ thin film by the growth and annealing temperatures were also confirmed.

• Korean Journal of Optics and Photonics
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• v.13 no.3
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• pp.215-222
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• 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 KSME Conference
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• 2003.11a
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• pp.1932-1938
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• 2003

We have applied spectroscopic ellipsometry to investigate $high-{\kappa}$ dielectric thin films and correlate their optical properties with fabrication processes, in particular, with high temperature annealing. The use of high-k dielectrics such as $HfO_{2}$, $Ta_{2}O_{5}$, $TiO_{2}$, and $ZrO_{2}$ as the replacement for $SiO_{2}$ as the gate dielectric in CMOS devices has received much attention recently due to its high dielectric constant. From the characteristics found in the pseudo-dielectric functions or the Tauc-Lorentz dispersions, the optical properties such as optical band gap, polycrystallization, and optical density will be discussed.

• Proceedings of the KIEE Conference
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• 1994.11a
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• pp.240-242
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• 1994

Spectroscopic ellipsometry(SE) was employed to characterize the Si/$Si_{1-x}Ge_x$ heterostructure. The dielectric function spectrum of $Si_{1-x}Ge_x$ at an arbitrary x value in the spectral range of $1.5{\sim}4.5\;eV$ was computed by EMA (effective medium approximation) model using the available optical constants measured at a number of fixed x values of Ge composition. The thickness and the Ge composition of $Si_{1-x}Ge_x$ measured by SE was compared with those measured by RBS. DC bias effect on the $E_2$ peak of dielectric function spectra was studied.

• Current Optics and Photonics
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• v.7 no.4
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• pp.428-434
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• 2023

The compensators used in spectroscopic ellipsometers are usually assumed to be ideal linear waveplates. In reality, however, they are elliptical waveplates, because they are usually made by bonding two or more linear waveplates of different materials with slight misalignment. This induces systematic error when they are modeled as linear waveplates. We propose an improved calibration method based on an optical model that regards an elliptical waveplate as a combination of a circular waveplate (rotator) and a linear waveplate. The method allows elimination of the systematic error, and the residual error of optic axis measurement is reduced to 0.025 degrees in the spectral range of 450-800 nm.

• Advances in nano research
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• v.5 no.3
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• pp.261-279
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• 2017

Spectroscopic investigation of Si quantum dots (Si-QDs) embedded in silicon nitride was performed over a broad stoichiometry range to optimize light emission. Plasma-enhanced chemical vapor deposition was used to grow the $SiN_x$ films on Si (001) substrates. The film composition was controlled via the flow ratio of silane ($SiH_4$) and ammonia ($NH_3$) in the range of R = 0.45-1.0 allowed to vary the Si excess in the range of 21-62 at.%. The films were submitted to annealing at $1100^{\circ}C$ for 30 min in nitrogen to form the Si-QDs. The properties of as-deposited and annealed films were investigated using spectroscopic ellipsometry, Fourier transform infrared spectroscopy, Raman scattering and photoluminescence (PL) methods. Si-QDs were detected in $SiN_x$ films demonstrating the increase of sizes with Si excess. The residual amorphous Si clusters were found to be present in the films grown with Si excess higher than 50 at.%. Multi-component PL spectra at 300 K in the range of 1.5-3.5 eV were detected and nonmonotonous varying total PL peak versus Si excess was revealed. To identify the different PL components, the temperature dependence of PL spectra was investigated in the range of 20-300 K. The analysis allowed concluding that the "blue-orange" emission is due to the radiative defects in a $SiN_x$ matrix, whereas the "red" and "infrared" PL bands are caused by the exciton recombination in crystalline Si-QDs and amorphous Si clusters. The nature of radiative and no radiative defects in $SiN_x$ films is discussed. The ways to control the dominant PL emission mechanisms are proposed.