• 한국표면공학회지
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• 제32권3호
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• pp.467-471
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• 1999

BN films were grown on silicon (l00) substrate by magnetically enhanced activated reactive evaporation (ME-ARE) with pulsed DC power instead of r.f. for substrate biasing. The deposited films were analyzed using Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). FTIR results show that the intensity of absorption band of $sp^2$ bond of BN decreased and that of $sp^3$ bond of c-BN increased with increasing pulsed DC bias voltage applied to substrate. The initially grown layer at the interface was observed by TEM and considered to be of$ sp^2$-bonded BN. The cross-sectional and planar TEM micrographs show that the upper layer on the initial layer was the single phase c-BN. It is concluded that cubic boron nitride films could be synthesized by ME-ARE process with pulsed DC biasing.

• 한국진공학회:학술대회논문집
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• 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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• pp.126-126
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• 1999

본 실험의 목적은 FED의 상부, 하부 전극으로 사용되는 Mo를 건식, 습식 식각함으로써 DED 소자의 공정을 개발하는 것이다. Mo는 $261^{\circ}C$의 높은 융점을 지니고 있으며, 우수한 열적 안정성과 비교적 낮은 비저항을 가지는 재료로써 FED와 같은 전계 방출 소자의 cathod 팁 및 전극물질로 사용되어지는 가장 보편적인 물질이다. FED와 같은 전계방출소자가 갖추어야 할 요건은 전자 방출 영역이 소자 동작시 변형되지 않아야 하고, 기계적 ,화학적, 열적 내구성이 좋아야 함인데 이러한 요건을 충족시킬 수 있고 가장 범용적으로 사용되는 물질이 Mo이다. 실험에서 사용된 Mo는 DC magnetron sputter를 사용하여 Ar 가스를 첨가하여 5mTorr하에서 Si 기판위에 증착속도를 300$\AA$/min로 하여 1.6$\mu\textrm{m}$ 증착하였다. 본 실험의 Mo 식각은 고밀도 플라즈마원인 ICP를 이용하였다. 식각특성은 식각 가스조합, inductive power, bias voltage, 공정 압력의 다양한 공정 변수에 따른 식각특성 변화를 관찰하였다. 식각시 chlorine 가스를 주요 식각 가스로 사용하고 BCl3, O2, Ar을 첨가가스로 사용하였으며, inductive power는 300-600, bias voltage는 120-200V 사용하였고 압력은 15-30mTorr, 기판온도는 7$0^{\circ}C$로 유지하였으며 식각마스크로는 electron-beam evaporator로 1$\mu\textrm{m}$ 증착한 SiO2를 patterning하여 사용하였다. 식각속도는 stylus profiler를 이용하여 측정하였으며 식각후 profile은 scanning electron microscopy (SEM)을 통하여 관찰하였다. 실험 결과 순수한 Cl2 BCl3 가스만을 사용한 경우 보다는 Cl2 가스에 O2를 첨가하였을 때 좋은 선택비를 얻었다. 또한, inductive power와 bias voltage, Mo의 식각속도의 적절한 조절을 통해 SiO2에 대한 선택도를 변화시킬 수 있었다. Cl2:O2비를 1:1로 하고 400W/-150V, 20mTorr의 압력, 7$0^{\circ}C$ 기판온도에서 식각시 200$\AA$/min의 Mo 식각속도, SiO2와의 선택비 8:1을 얻을 수 있었다. 또한 실제 FED 소자 구조형성에 적용한 결과 비등방적인 식각형상을 형성할 수 있었다.

• 센서학회지
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• 제24권3호
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• pp.181-187
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• 2015

The magnetoelectric characteristics on layered $Fe_{78}B_{13}Si_9/PZT$ and $Fe_{78}B_{13}Si_9/PZT/Fe_{78}B_{13}Si_9$($t_m=0.017$, 0.034mm) composites by epoxy bonding for magnetic field sensor were investigated in the low-frequency range and resonance frequency range. The optimal bias magnetic field $H_{dc}$ of these samples was about 23~63 Oe range. The Me coefficient of $Fe_{78}B_{13}Si_9/PZT/Fe_{78}B_{13}Si_9(t_m=0.034mm)$ composites reaches a maximum of $186mV/cm{\cdot}Oe$ at $H_{dc}=63Oe$, f=50 Hz and a maximum of $1280mV/cm{\cdot}Oe$ at $H_{dc}=63Oe$, resonance frequency $f_r=95.5KHz$. The output voltage shows linearity proportional to ac fields $H_{ac}$ and is about U=0~130.6 mV at $H_{ac}=0{\sim}7Oe$, f=50 Hz, U=0~12.4 V at $H_{ac}=0{\sim}10Oe$, $f_r=95.5KHz$(resonance frequency). The optimal frequency(f=50 Hz) of this sample is around the utility ac frequency(f=60 Hz). Therefore, this sample will allow for ac magnetic field sensor at utility frequency and low bias magnetic fields $H_{dc}$.

• Journal of Magnetics
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• 제16권3호
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• pp.211-215
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• 2011

The dynamic magnetostriction characteristics of an Fe-based nanocrystalline FeCuNbSiB alloy are investigated as a function of the dc bias magnetic field. The experimental results show that the piezomagnetic coefficient of FeCuNbSiB is about 2.1 times higher than that of Terfenol-D at the low dc magnetic bias $H_{dc}$ = 46 Oe. Moreover, FeCuNbSiB has a large resonant dynamic strain coefficient at quite low Hdc due to a high mechanical quality factor, which is 3-5 times greater than that of Terfenol-D at the same low $H_{dc}$. Based on such magnetostriction characteristics, we fabricate a new type of transducer with FeCuNbSiB/PZT-8/FeCuNbSiB. Its maximum resonant magnetoelectric voltage coefficient achieves ~10 V/Oe. The ME output power reaches 331.8 ${\mu}W$ at an optimum load resistance of 7 $k{\Omega}$ under 0.4 Oe ac magnetic field, which is 50 times higher than that of the previous ultrasonic-horn-substrate composite transducer and it decreases the size by nearly 86%. The performance indicate that the FeCuNbSiB/PZT-8/FeCuNbSiB transducer is promising for application in highly efficient magnetoelectric energy conversion.

• 전자공학회논문지T
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• 제36T권1호
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• pp.8-12
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• 1999

산소이온 펌핑효과를 나타내는 8% 이트리아가 함유된 ZrO\sub 2\ 이온 전도체를 기판으로 하여 그 위에 NO\sub x\가스에 대해 감지효과를 갖고 있는 것으로 알려져 있는 WO\sub 3\산화물 반도체를 사용하여 박막시편을 제작하였다. 각 소자의 NO\sub x\ 가스에 대한 전기적 특성과 열처리 온도에 따른 미세구조의 변화를 조사하였고, 특히 8YSZ 기판에 가해준 전압에 의한 NO\sub x\ 가스 감지의 증대효과를 조사하였다. 열처리 온도에 따른 WO\sub 3\ 박막표면의 SEM사진의 분석에서 열처리하지 않은 WO\sub 3\ 박막은 비결정질 상태이지만 600℃이상의 열처리 온도에서 결정화가 이루어졌고 사방경계상의 WO\sub 3\ 피크가 나타났으며 온도가 증가함에 따라 (111)면과 (001)면이 특히 많이 성장하였다. 측정온도 400℃에서 8YSZ 기판에 전압을 가하지 않았을 때보다 전압을 가하였을 경우가 더 안정되고 더 큰 응답을 보였으며, 특히 2V 일 때가 가장 높은 감도를 나타내었다. 그리고 NO\sub 2\ 가스보다 NO 가스에 대한 회복특성이 훨씬 우수했다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2007년도 7th International Meeting on Information Display 제7권2호
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• pp.1172-1175
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• 2007

We have investigated the threshold voltage shifts(${\Delta}Vth$) and drain current level shift (${\Delta}Ids$) in subthreshold region of a-Si:H TFTs induced by DC Bias (Vgs and Vds) - Temperature stress (BTS) condition. We plotted the transfer curves and the ${\Delta}Vth$ contour maps as Vds-Vds stress bias and Temperature to examine the severe damage cases on TFTs. Also, by drawing out the time-dependent transfer curve (Ids-Vgs) in the region of $10^{-8}\;{\sim}\;10^{-13}$ (A) current level, we can estimate the failure time of TFTs in a operating condition.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.465-465
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• 2010

Cut off probe, the efficient method, can measure the plasma parameters like the plasma electron density and the electron temperature. Plasma potential is also one of the important parameters in plasma processing but cannot be measured by cut off probe yet. Thus we developed method to measure plasma potential by focusing on relation between bias on a tip and sheath around tip. The system consist of a ICP(Inductive Coupled Plasma) source, a Network analyzer and a bias tee that can be bridge apply DC voltage on the cut off probe tip. Plasma potential is identified by using this system. The results corresponded well with the measured results by single langmuir probe(SLP).

• 열처리공학회지
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• 제36권3호
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• pp.115-120
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• 2023

ZnO/Cu/ZnO (ZCZ) thin film deposited on the glass substrate with DC and RF magnetron sputtering was rapid thermal annealed (RTA) and then effect of thermal temperature on the opto-electical and transparent heater properties of the films were considered. The visible transmittance and electrical resistivity are depends on the annealing temperature. The electrical resistivity decreased from 1.68 × 10^-3 Ωcm to 1.18 × 10^-3 Ωcm and the films annealed at 400℃ show a higher transmittance of 78.5%. In a heat radiation test, when a bias voltage of 20 V is applied to the ZCZ film annealed at 400℃, its steady state temperature is about 70.7℃. In a repetition test, the steady state temperature is reached within 15s for all of the bias voltages.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.616-619
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• 2003

This work presents the design, fabrication and microwave performance of distributed analog phase shifter (DAPS) fabricated on $(Ba,\;Sr)TiO_3$ (BST) thin films for X-band applications. Ferroelectric BST thin films were deposited on MgO substrates by pulsed laser deposition. The DAPS consists of high impedance coplanar waveguide (CPW) and periodically loaded tunable BST interdigitated capacitors (IDC). In order to reduce the insertion loss of DAPS and to remove the alteration of unloaded CPW properties according to an applied dc bias voltage, BST layer under transmission lines were removed by photolithography and RF-ion milling. The measured results are in good agreement with the simulated results at the frequencies of interest. The measured differential phase shift based on BST thin films was $24^{\circ}$ and the insertion loss decreased from 1.1 dB to 0.7 dB with increasing the bias voltage from 0 to 40V at 10 GHz.

• 연구논문집
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• 통권28호
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• pp.219-227
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• 1998

In order to investigate the interfacial structure between TiN and iron nitride, an AISI 4140 steel was nitrided to form a layer of thickness 15$\mum$ by DC ion nitriding, then the surface was bombarded with Ti ions and subsequently coated a TiN film of 5$\mum$ by arc ion plating method. The interfacial microstructure between TiN and iron nitride was characterized by optical microscope, SEM and XRD. So called black layer was observed in the duplex treatment. It was resulted from the decomposition of iron nitride during the bombardment. Its thickness was increased with increasing bombardment time at high bias voltage. But the thickness was greatly decreased when the iron nitride was bombarded with a nitrogen gas or at a reduced bias voltage. The adhesion strength of the top TiN coating was decreased with increasing thickness of the black layer. Furthermore, the reduced adhesion strength in this system was discussed in view of the interfacial structural relationship between TiN and iron nitride.