• Transactions on Electrical and Electronic Materials
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• 제12권5호
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• pp.209-212
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• 2011

Hafnium nitride (HfN) thin films were deposited onto a silicon substrate by inductive coupled nitrogen plasma-assisted radio frequency magnetron sputtering. The films were prepared without intentional substrate heating and a substrate negative bias voltage ($-V_b$) was varied from -50 to -150 V to accelerate the effects of nitrogen ions ($N^+$) on the substrate. X-ray diffractometer patterns showed that the structure of the films was strongly affected by the negative substrate bias voltage, and thin film crystallization in the HfN (100) plane was observed under deposition conditions of -100 $V_b$ (bias voltage). Atomic force microscopy results showed that surface roughness also varied significantly with substrate bias voltage. Films deposited under conditions of -150 $V_b$ (bias voltage) exhibited higher hardness than other films.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제42회 동계 정기 학술대회 초록집
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• pp.430-430
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• 2012

Modulated pulsed power (MPP) 스퍼터링은 펄스 전압 shape, amplitude, duration의 modulation을 통해 증착율 손실을 극복하는 고출력 펄스 마그네트론 스퍼터링의 한 종류이다. Micro second 범위에서 on/off 시간을 다중 세트 형태로 자유롭게 프로그램 할 수 있어서 아킹 없이 고전류 영역의 마그네트론 동작을 할 수 있으므로, 고주파 유도 결합 플라즈마원이나 마이크로웨이브 투입 등의 부가적인 플라즈마 없이도 스퍼터링 재료의 이온화 정도를 획기적으로 높일 수 있는 장점을 가지고 있다. 본 연구에서는 $2{\times}1{\times}0.2$의 sputtering system에서 기판 캐리어를 이용해서 $400{\times}400mm$ 기판을 $272{\times}500mm$ 크기의 AZO target (Al 2 wt%)이 설치되어 있는 moving magnet cathode (MMC)을 이용하여 MPP로 증착했다. 두 종류의 micro pulse set을 하나의 macro pulse에 사용함으로서 weakly ionized plasma와 strongly ionized plasma를 만들 수 있다. 다양한 micro pulse set을 이용하여 평균 전력 2 kW에서 peak 전력을 4 kW에서 45 kW까지 상승 시킬 수 있으며, 이 때 타겟-기판 거리 80 mm에서 이온전류밀도는 $5mA/cm^2$에서 $20mA/cm^2$까지 상승했다. MPP는 같은 평균 전력에서 repetition frequency가 증가할 때, 증착 속도가 증가했으며, 같은 repetition frequency에서 macro pulse length가 증가할 때도, 증착 속도가 증가했다. 최적화된 marco, micro pulse set에서 증착 속도는 평균 전력 2 kW에서 110 nm/min이었고, 700 nm의 박막에서 비저항은 $1-2{\times}10^{-3}ohm{\cdot}cm$였다. 표면거칠기 Rrms는 약 3 nm였고, 400-700 nm 영역의 평균 투과도는 72-76%였다.

• 한국전기전자재료학회논문지
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• 제20권8호
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• pp.701-705
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• 2007

The incorporation of N in a-C film is able to improve the friction coefficient and the adhesion to various substrates. In this study, a-C:N films were deposited on Si and steel substrates by closed-field unbalanced magnetron (CFUBM) sputtering system in $Ar/N_2$ plasma. The lubricant characteristics was investigated for a-C:N deposited with total working pressure from 4 to 7 mTorr. We obtained high hardness up to 24GPa, friction coefficient lower than 0.1 and the smooth surface of having the extremely low roughness (0.16 nm). The physcial properties of a-C:N thin film are related to the increase of cross-linked $sp^2$ bonding clusters in the film. However, the decrease of hardness, elastic modulus and the increase of surface roughness, friction coefficient with the increase of $N_2$ partial pressrue might be due to the effect of energetic ions as a result of the increase of ion bombardment with the increase of ion density in the plasma.

• 한국표면공학회지
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• 제36권2호
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• pp.148-154
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• 2003

Short ($\tau$=40 $mutextrm{s}$) and high-voltage ($U_{sub}$=2~8 kV) negative substrate bias pulses were used to assist pulsed magnetron sputtering DLC films deposition. Space- and time-resolved probe measurements of the plasma characteristics have been performed. It was shown that in case of high-voltage substrate bias spatial non-uniformity of the magnetron discharge plasma density greatly affected DLC deposition process. By Raman spectroscopy it was found that maximum percentage of s $p^3$-bonded carbon atoms (40 ~ 50%) in the coating was attained at energy $E_{c}$ ~700 eV per deposited carbon atom. Despite rather low diamond-like phase content these coatings are characterized by good adhesion due to ion mixing promoted by high acceleration voltage. Short duration of the bias pulses is also important to prevent electric breakdowns of insulating DLC film during its growth.wth.

• 한국재료학회지
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• 제24권7호
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• pp.344-350
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• 2014

Metal films (i.e., Ti, Al and SUH310S) were prepared in a magnetron sputtering apparatus, and their cross-sectional structures were investigated using scanning electron microscopy. The apparatus used consisted of a cylindrical metal target which was electrically grounded, and two anode rings attached to the top and to the bottom of the target. A wire was placed along the center-line of the cylindrical target to provide a substrate. When the electrical potential of the substrate was varied, the metal-film formation rate depended on both the discharge voltage and the electrical potential of the substrate. As we made the magnetic field stronger, the plasma which appeared near the target collected on the plasma wall surface and thereby decreased the bias current. The bias current on the conducting wire was different from that for cation collection. The bias current decreased because the collection of cations decreased when we increased the magnetic-coil current. When the substrate was electrically isolated, the films deposited showed a slightly coarse columnar structure with thin voids between adjacent columns. In contrast, in the case of the grounded substrate, the deposited film did not show any clear columns but instead, showed a densely-packed granular structure. No peeling region was observed between the film and substrate, indicating good adhesion.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.419-421
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• 2008

Sputter deposition on a Pt counter electrode was studied using RF plasma as the improvement of conversion efficiency for dye-sensitized solar cells (DSC). The effects of the sputtering thickness and incident angle on a Pt counter electrode for DSC was scrutinized. We conducted the experiment to get the optimal sputtering time for the performance of the DSC. Under the sputtering time condition of 120 seconds, we varied the incident angles of substrate from $0^{\circ}$ to $60^{\circ}$. Under standard test condition (AM 1.5, 100mW/$cm^2$), we obtained the maximum efficiency of 4.61% at the incident angle of $40^{\circ}$ with an active cell area of $1cm^2$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.880-883
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• 2003

ZnO thin films for Film Bulk Acoustic Resonator(FBAR) were prepared by FTS (Facing Target Sputtering) system. The FTS methode enable to generate high density plasma, and it has a high deposition rate at 1mTorr pressure. Therefore, the ZnO thin films were deposited on $AZO/SiO_2/Si$ substrates with oxygen gas flow rate, and the other sputtering conditions were fixed such as a sputtering current of 0.8A, a substrate temperature at room temperature. AZO bottom electrode were deposited on $SiO_2/Si$ substrate and by Zn:Al(Al:2wt%) metal target. ZnO thin film thickness and the c-axis preferred orientation of ZnO thin film were evaluated by ${\alpha}-step$ and XRD.

• Journal of Advanced Marine Engineering and Technology
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• 제24권6호
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• pp.139-146
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• 2000

The development of high performance materials is very important subject in order to enhance the properties of bearings whose role is to transfer energy harmoniously by reducing the problem of friction and wear down, etc. between the interacting solid surfaces in relative motion under high loads in comply with mechanical operating mechanism of engines. In this study, several (100-x)Al-xSn coating films (where x=85, 75, 65 atomic % at Al) on substrates which are abt. 2mm thickenss of Kelmet layer sintered back steel were prepared by using RF sputtering system. These coating films were observed the morphology by SEM(Scanning Electron Microscope) and investigated the crystal structure by XRD(X-ray Diffractor) for their properties. And friction coefficient of these films was measured by ball-on-disc tester for their tribological properties. From the experimental results, it was shown that high performance properties of bearing can be improved greatly by controlling the composition and morphology of material surface with effective use of the plasma-assisted sputtering process.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.50-50
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• 2011

The aluminum nitride films were prepared by RF magnetron sputtering using an AlN ceramic target. The crystallinity, grain size, Al-N bonding and thermal conductivity were investigated in dependence on the plasma power densities (4.93, 7.40, 9.87 W/$cm^2$) during sputtering. High thermal conductivity is important properties of A1N passivation layer for functioning properly in thermal inkjet printhead. The crytallinity, grain size, Al-N bonding formation and chemical composition were observed using X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), fourier transform infrared (FTIR) and X-ray photoelectron spectroscopy (XPS), respectively. The AlN thin film was changed from amorphous to crystalline as the power density was increased, and the largest grain size appeared at medium power density. The near stoichiometry Al-N bonding ratio was acquired at medium power density. So, we know that the AlN thin film had better thermal conductivity with crystalline phase and near stoichometry Al-N bonding ratio at 7.40 W/$cm^2$ power density.

• Corrosion Science and Technology
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• 제3권4호
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• pp.148-153
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• 2004

Magnesium thin flims were prepared on cold-rolled steel substrates by RF magnetron sputtering technique. The influence of argon gas pressure and substrate bias voltage on their crystal orientation and morphology of the coated films were investigated by scanning electron microscopy (SEM) and X-ray diffraction, respectively. And the effect of crystal orientation and morphology of magnesium films on corrosion behaviors was estimated by measuring anodic polarization curves in deaerated 3%NaCl solution. From the experimental results, all the sputtered magnesium films showed obviously good corrosion resistance to compare with 99.99% magnesium target of the sputter-evaporation metal. Finally it was shown that the Corrosion-resistance of magnesium films can be improved greatly by controlling the crystal orientation and morphology with effective use of the plasma sputtering technique.