• 한국전기전자재료학회논문지
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• 제20권11호
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• pp.932-938
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• 2007

The structural, optical, and electrical properties of ZnO thin films grown on glass by radio-frequency (rf) magnetron sputtering were investigated. The mixture flow ratio of $O_2$ to Ar, which was operated with sputtering gas, was chosen as a parameter for growing high-qualify ZnO thin films. The structural properties and surface morphologies of the thin films were characterized by the X-ray diffraction and the atomic force microscope, respectively. As for the optical properties of the films, the optical absorbance was measured in the wavelength range of 300-1100 nm by using UV-VIS spectrophotometer. The optical transmittance, absorption coefficient, and optical bandgap energy of ZnO thin films were calculated from the measured data. The crystallinity of the films was improved and the bandgap energy was increased from 3.08 eV to 3.23 eV as the oxygen flow ratio was increased from 0 % to 50 %. Furthermore, The ultraviolet and violet luminescences were observed by using photoluminescence spectroscopy. The hall mobility was decreased with the increase of oxygen flow ratio.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2014년도 제46회 동계 정기학술대회 초록집
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• pp.248.2-248.2
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• 2014

In this study, the optical properties and structural characteristics of gallium nitride (GaN) thin films prepared by radio frequency (RF) magnetron sputtering were investigated. Auger electron and X-ray photoelectron spectra showed that the deposited films consisted mainly of gallium and nitrogen. The presence of oxygen was also observed. The optical bandgap of the GaN films was measured to be approximately 3.31 eV. The value of the refractive index of the GaN films was found to be 2.36 at a wavelength of 633 nm. X-ray diffraction data revealed that the crystalline phase of the deposited GaN films changed from wurtzite to zinc-blende phase upon decreasing the sputtering gas pressure. Along with the phase change, a strong dependence of the microstructure of the GaN films on the sputtering gas pressure was also observed. The microstructure of the GaN films changed from a voided columnar structure having a rough surface to an extremely condensed structure with a very smooth surface morphology as the sputtering gas pressure was reduced. The relationship between the phase and microstructure changes in the GaN films will be discussed.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.169-169
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• 2016

In this paper, we report electrical, optical and structural properties of Al-doped zinc oxide (AZO) thin films deposited at different substrate temperatures and pressures. The films were prepared by radio frequency (RF) magnetron sputtering on glass substrates in argon (Ar) ambient. The X-ray diffraction analysis showed that the AZO films deposited at room temperature (RT) and 20 Pa were mostly oriented along a-axis with preferred orientation along (100) direction. There was an improvement in resistivity ($3.7{\times}10^{-3}{\Omega}-cm$) transmittance (95%) at constant substrate temperature (RT) and working pressure (20 Pa) using the Hall-effect measurement system and UV-vis spectroscopy, respectively. Our results have promising applications in low-cost transparent electronics, such as the thin-film solar cells and thin-film transistors due to favourable deposition conditions. Furthermore our film deposition method offers a procedure for preparing highly oriented (100) AZO films.

• 한국표면공학회지
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• 제41권4호
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• pp.129-133
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• 2008

Nitrogen and aluminum codoped ZnO(NAZO) thin films were grown on glass substrates with changing the nitrogen flow ratio by radio-frequency magnetron sputtering. The structural, optical, and electrical properties of the NAZO films were investigated. The surface morphologies and the structural properties of the thin films were analyzed by using the X-ray diffraction and scanning electron microscopy. The NAZO thin film, deposited at nitrogen flow ratio of 0%, showed a strongly c-axis preferred orientation and the lowest resistivity of $3.2{\times}10^{-3}{\Omega}cm$. The intensity of ZnO(002) diffraction peak was decreased gradually with increasing the nitrogen flow ratio. The optical properties of the films were measured by UV-VIS spectrophotometer and the optical transmittances for all the samples were found to be an average 90% in the visible range. Based on the transmittance value, the optical bandgap energy for the NAZO thin film deposited at nitrogen flow ratio of 0% was determined to be 3.46 eV. As for the electrical properties, the carrier concentration and the hall mobility were decreased, but the electrical resistivity was increased as the nitrogen flow ratio was increased.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2013년도 제45회 하계 정기학술대회 초록집
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• pp.291.2-291.2
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• 2013

Growth behavior of b-Ga2O3 nanowires (NWs) on sapphire(0001) substrates during radio-frequency magnetron sputtering is reported. Upon fabrication, flat thin films grew initially, subsequent to which, NW bundles were formed on the surface of thin film with increasing film thickness. This transition of the growth mode occurred only at temperatures greater than ${\sim}450^{\circ}C$. The b-Ga2O3 NWs were grown through the self-catalytic vapor-liquid-solid mechanism with self-assembled Ga seeds. Secondary growth of NWs, which occurred from the sides of primary NWs resulting in branched NW structures, was also observed. Finally, the room temperature photoluminescence properties of as-grown and annealed b-Ga2O3 NW samples were investigated.

• 한국안광학회지
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• 제3권1호
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• pp.115-120
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• 1998

RF(radio-frequency) magnetron 스퍼터링 장치에 질소가스와 아르곤가스를 동시에 주입하면서 Ti 타켓을 스퍼터링하여 $TiN_x$ 박막을 유리기판위에 제작하였다. 박막제작시 RF power supply 출력을 240W로, 증착기 내부의 온도는 $200^{\circ}C$를 유지하였다. $TiN_x$ 박막은 알곤 가스를 20sccm으로 고정시킨 상태에서 질소를 3sccm부터 9sccm까지 변화시켜가며 증착시켰다. 이때 박막의 화학적 조성과 성분비를 분석하기 위하여 XPS를 사용하였다.

• 한국안광학회지
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• 제4권1호
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• pp.21-25
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• 1999

RF(radio-frequency) magnetron 스퍼터링 장치에 질소가스와 아르곤가스를 동시에 주입하면서 Ti 타켓을 스퍼터링하여 TiN, 박막을 유리기판위에 제작하였다. 박막제작시 RF power supply 출력은 240W로, 증착기 내부의 온도는 $200^{\circ}C$를 유지하였다. TiN, 박막은 알곤 가스를 20sccm으로 고정시킨 상태에서 질소를 3sccm부터 9secm까지 변화시켜가며 증착시켰다. 이때 박막의 면저항과 화학적 조성과의 관계를 분석하기 위하여 XPS depth profiling과 4점 탐침법을 사용하였다.

• Transactions on Electrical and Electronic Materials
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• 제11권2호
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• pp.81-84
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• 2010

Al-doped ZnO (AZO) films were prepared by an Ar:$H_2$ gas radio frequency (RF) magnetron sputtering system with a AZO ($2\;wt{\cdot}%\;Al_2O_3$) ceramic target at the low temperature of $100^{\circ}C$ and annealed in hydrogen ambient at the temperature of $300^{\circ}C$. To investigate the influence of the $H_2$ flow ratio on the properties of the AZO films, the $H_2$ flow ratio was changed from 0.5% to 2%. As a result, the AZO films, deposited with a 1% $H_2$ addition, showed a resistivity of $11.7\;{\times}\;10^{-4}\;{\Omega}{\cdot}cm$. When the AZO films were annealed at $300^{\circ}C$ for 1 hour in a hydrogen atmosphere, the resistivity decreased from $11.7\;{\times}\;10^{-4}\;{\Omega}{\cdot}cm$ to $5.63\;{\times}\;10^{-4}\;{\Omega}{\cdot}cm$. The lowest resistivity of $5.63\;{\times}\;10^{-4}{\Omega}{\cdot}cm$ was obtained by adding 1% hydrogen gas to the deposition and annealing process. The X-ray diffraction patterns of all the films showed a preferable growth orientation in the (002) plane. The spectrophotometer measurements showed that the transmittance of 85% was obtained by the film deposited with the $H_2$ flow ratio of 1% at 940 nm for GaAs/GaAlAs LEDs.

• Korean Chemical Engineering Research
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• 제46권4호
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• pp.676-680
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• 2008

Radio-frequency (rf) 마그네트론 스퍼터링법을 이용하여 $SiO_2(2000{\AA})/Si$ 기판위에 TiN 박막이 증착되었다. $N_2/Ar$ 혼합가스에서 $N_2$ 가스의 농도, rf power, 공정압력 등을 변화시켜서 TiN 박막이 증착되었고 증착된 박막의 증착속도, 전기저항도 및 표면의 거칠기 등이 조사되었다. $N_2$ 가스의 농도가 증가함에 따라서 증착속도는 감소하였고 저항도는 증가하였으며 표면의 거칠기는 감소하였다. rf power가 증가함에 따라서 증착속도는 증가하였지만 저항도는 감소하였다. 증착압력의 증가에 따라서 증착속도는 큰 변화가 없었지만 저항도가 급격히 증가하였으며, 1 mTorr의 압력에서 $2.46{\times}10^{-4}{\Omega}cm$의 저항도를 갖는 TiN 박막이 얻어졌다. 박막의 증착속도와 저항도는 상관관계가 있는 것이 관찰되었고 특히 증착압력이 박막의 저항도에 가장 큰 영향을 미치는 것을 알 수 있었다.

• 한국태양에너지학회 논문집
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• 제26권4호
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• pp.55-61
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• 2006

Titanium oxide ($TiO_2$) films are deposited on the indium tin oxide (ITO) substrate in an $Ar/O_2$ atmosphere by using reactive RF (Radio Frequency) magnetron sputtering technique, and Electrochromic properties and durability of $TiO_2$ films deposited at different preparation conditions are investigated by using UV-VIS spectrophotometer and cyclic voltammetry Li+ interalation/deintercalation in $TiO_2$ films shows that the electrochromic properties and durability of as-deposited films strongly depend on gas pressure $TiO_2$ films formed in our sputtering conditions are found to remain transparent, irrespective of their Li+ ion contents. The optimum sputtering conditions for film as passive counter electrode in electrochromic devices are working pressure of $1.0\;{\times}\;10^{-2}\;torr$ and oxygen flow raes of $10{\sim}15\;sccm$, respectively.