• 한국재료학회지
• /
• 제20권1호
• /
• pp.47-50
• /
• 2010

Various thicknesses of Al-doped ZnO (AZO) films were deposited on glass substrate using pulsed dc magnetron sputtering with a cylindrical target designed for large-area high-speed deposition. The structural, electrical, and optical properties of the films of various thicknesses were characterized. All deposited AZO films have (0002) preferred orientation with the c-axis perpendicular to the substrate. Crystal quality and surface morphology of the films changed according to the film thickness. The samples with higher surface roughness exhibited lower Hall mobility. Analysis of the measured data of the optical band gap and the carrier concentration revealed that there were no changes for all the film thicknesses. The optical transmittances were more than 85% regardless of film thickness within the visible wavelength region. The lowest resistivity, $4.13\times10^{-4}\Omega{\cdot}cm^{-1}$ was found in 750 nm films with an electron mobility $(\mu)$ of $10.6 cm^2V^{-1} s^{-1}$ and a carrier concentration (n) of $1.42\times10^{21} cm^{-3}$.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제52권7호
• /
• pp.288-292
• /
• 2003

AlM thin film has been deposited on A1$_2$O$_3$ substrate by reactive radio frequency(RF) magnetron sputtering method under various operating conditions such as working pressure, fraction of nitrogen partial pressure, and substrate temperature. Scanning Electron Microscope(SEM), X-ray Diffraction(XRD), and Atomic Force Microscope(AFM) have been measured to find out structural properties and preferred orientation of AlN thin films. SAW velocity of IDTs/AlN/Si structure was about 5038［㎧］ at the center frequency of 251.9［MHz］ and insertion loss was measured to be relatively low value of 35.6［dB］. SAW velocity of IDTs/AlN/A1$_2$O$_3$ structure was improved to be about 5960［㎧］ at the center frequency of 296.7［MHz］.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
• /
• pp.120-121
• /
• 2006

To investigate the ZnO thin films which are interested in the next generation of short wavelength LEDs and Lasers, the ZnO thin films were deposited by RF magnetron sputtering system. Al sputtering process of ZnO thin films substrate temperature, work pressure respectively is $100^{\circ}C$ and 15 mTorr, and the purity of target is ZnO 5N. The ZnO thin films were in-situ annealed at $600^{\circ}C$, $800^{\circ}C$ in $O_2$ atmosphere. Phosphorus (P) and arsenic (As) were diffused into ZnO thin films sputtered by RF magnetron sputtering system in ampoule tube which was below $5{\times}10^{-7}$ Torr. The dopant sources of phosphorus and arsenic were $Zn_3P_2$ and $ZnAS_2$. Those diffusion was perform at $650^{\circ}C$ during 3hr. We confirmed that p-type properties of ZnO thin films were concerned with dopant sources rather than diffusion temperature.

• 한국재료학회지
• /
• 제20권12호
• /
• pp.629-635
• /
• 2010

Abstract In this study characteristics of Al-doped ZnO thin film by HIPIMS (High power impulse sputtering) are discussed. Deposition speed of HIPIMS with conventional balanced magnetic field is measured at about 3 nm/min, which is 30% of that of conventional RF sputtering process with the same working pressure. To generate additional magnetic flux and increase sputtering speed, electromagnetic coil is mounted at the back side of target. Under unbalanced magnetic flux from electromagnet with 1.5A coil current, deposition speed of AZO thin film is increased from 3 nm/min to 4.4 nm/min. This new value originates from the decline of particles near target surface due to the local magnetic flux going toward substrate from electromagnet. AZO film sputtered by HIPIMS process shows very smooth and dense film surface for which surface roughness is measured from 0.4 nm to 1 nm. There are no voids or defects in morphology of AZO films with varying of magnetic field. When coil current is increased from 0A to 1A, transmittance of AZO thin film decreases from 80% to 77%. Specific resistance is measured at about $2.9{\times}10-2\Omega{\cdot}cm$. AZO film shows C-axis oriented structure and its grain size is calculated at about 5.3 nm, which is lower than grain size in conventional sputtering.

• 한국산학기술학회논문지
• /
• 제8권5호
• /
• pp.1057-1061
• /
• 2007

본 연구에서는 AlAs와 ZnO target을 사용하여 RF magnetron sputtering 시스템에서 layer-by-layer 방법으로 증착한 ZnO 박막의 특성에 대하여 조사하였다. 또한 열처리 전에 $H_2O_2$용액을 사용한 처리가 박막 특성에 미치는 영향도 조사하였다. 연구 결과 열처리 조건에 따라 n-형 또는 p-형 박막이 형성되는 것으로 관찰되었다. 이러한 결과는 박막의 전도 형태를 임의로 수정할 수 있음을 의미하는 동시에 박막 특성의 열적 불안정성을 암시하는 것이기도 하다. 144시간까지 스트레스를 인가한 후 측정한 박막 특성 결과 열처리 과정 중 발생하는 이러한 박막 특성 변화는 열처리 전 박막을 30% $H_2O_2$용액에 1분간 처리함으로써 억제할 수 있는 것으로 관찰되었다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2009년도 추계학술대회 논문집
• /
• pp.192-192
• /
• 2009

AZO films were prepared by $Ar:H_2$ gas RF magnetron sputtering system with a AZO (2wt% $Al_2O_3$) ceramic target at a low temperature of $100^{\circ}C$. To investigate the influence of $H_2$ flow ratio on the properties of AZO films, $H_2$ flow ratio was changed from 0.5% to 2%. As a result, the AZO films deposited with 1% $H_2$ addition showed electrical properties with a resistivity of $5.06{\times}10^{-3}{\Omega}cm$. The spectrophotometer-measurements showed the transmittance of 86.5% was obtained by the film deposited with $H_2$ flow ratio of 1% in the range of 940nm for GaAs/GaAlAs LED.

• 한국표면공학회지
• /
• 제42권3호
• /
• pp.122-127
• /
• 2009

Ga/Al doped ZnO (GAZO) thin films were prepared on non-alkali glass substrate by co-sputtering system using two DC cathodes equipped with AZO ($Al_2O_3$:2.0 wt%) target and GZO ($Ga_2O_3$:6.65 wt%) target. This study examined the influence of Al/Ga concentration and substrate temperature on the electrical, structural and optical properties of GAZO films. The lowest resistivity $1.95{\times}10^{-3}{\Omega}cm$ was obtained at room temperature. With increasing substrate temperature, resistivity of GAZO film decreased to a minimum value of $7.47{\times}10^{-4}{\Omega}cm$ at below $300^{\circ}C$. Furthermore, when 0.05% $H_2$ gas was introduced, resistivity of GAZO film decreased to $6.69{\times}10^{-4}{\Omega}cm$. All the films had a preferred orientation along the (002) direction, indicating that the deposited films have hexagonal wurtzite structure formed by the textured growth along the c-axis. The average transmittance of the films was more than 85% in the visible light range.

• 한국표면공학회지
• /
• 제45권2호
• /
• pp.53-60
• /
• 2012

Modulated Pulse Power (MPP) magnetron sputtering is a new high-power pulsed magnetron sputtering (HPPMS) technology which overcomes the low deposition rate problem by modulating the pulse voltage shape, amplitude, and the duration. Highly ionized magnetron sputtering can be performed without arcing because it can be controlled as multiple steps of micro pulses within one overall pulse period in the range of 500-3,000 ${\mu}s$. In this study, the various waveforms of discharge voltage and current for micro pulse sets of MPP were investigated to find the possibility of controlling the strongly ionized plasma mode. Enhanced ionization of the sputtered metal atoms was obtained by OES. Large grained columnar structure can be grown by the strongly ionized plasma mode in the AZO deposition using MPP. In the most highly ionized deposition condition, the preferred orientation of (002) plane decreased, and the resistivity, therefore, increased by the plasma damage.

• 한국전자파학회지:전자파기술
• /
• 제14권3호
• /
• pp.15-19
• /
• 2003

본 연구에서는 RF magnetron sputtering으로 상온에서 증착된 ZnO압전박막을 이용하여, 1.96 GHz 대역의 air gap type의 FBAR BPF를 개발하였다. FBAR BPF는 Si wafer에 절연막으로 열 산화막층(SiO$_2$)을 형성한 후, 형성된 산화막 위에 바닥전극(Al), ZnO압전층 그리고 상부전극(Mo)를 차례로 RF magnetron sputter장비를 사용하여 증착시키고, Si wafer를 dry etching하여 air hole을 구현함으로써 device를 제조하였다. 제조된 FBAR BPF의 ZnO압전층의 XRD분석 결과 (002)면 방향으로 우선 배향되었으며, XRC의 $\sigma$값은 1.018이었다. 삽입손실 1 dB 내외로 우수한 특성을 나타내었다.

• 대한전기학회논문지:전기물성ㆍ응용부문C
• /
• 제48권6호
• /
• pp.429-435
• /
• 1999

The $SrTiO_3$ thin films were prepared on Ag/TiN-coated and p-type bare Si(100) substrates by r.f. magnetron sputtering deposition technique. The electrical properties of the deposited films were investigated, which controlling deposition parameters such as substrate temperature and film thickness. The electrical properties ofthe $SrTiO_3$ films were measured using the capacitance-voltage(C-V) technique. The thickness dependence of the electrical properties of the $SrTiO_3$ films was analyzed of the connection with the films in series. The substrate affected the crystal structure and texture characteristics of the $SrTiO_3$ films. The resistivity of the film, sandwiched between Al and Ag films was measured, as a function of the temperature.