• 제목/요약/키워드: rf-electrode

검색결과 418건 처리시간 0.026초

$Ar^+$ RF 플라즈마 처리조건이 임베디드 PCB내 전극 Cu박막과 ALD $Al_2O_3$ 박막 사이의 계면파괴에너지에 미치는 영향 (Effect of $Ar^+$ RF Plasma Treatment Conditions on Interfacial Adhesion Energy Between Cu and ALD $Al_2O_3$ Thin Films for Embedded PCB Applications)

  • 박성철;이장희;이정원;이인형;이승은;송병익;정율교;박영배
    • 마이크로전자및패키징학회지
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    • 제14권1호
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    • pp.61-68
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    • 2007
  • 임베디드 PCB 기판내 유전체 재료인 Atomic Layer Deposition(ALD) $Al_2O_3$ 박막과 전극재료인 스퍼터 증착된 Cu박막 사이의 계면접착력을 $90^{\circ}$ 필 테스트방법으로 측정하여 순수 빔 굽힘을 가정한 에너지 평형 해석을 통하여 계면파괴에너지를 구하였다. $Cu/Al_2O_3$의 계면파괴에너지(${\Gamma}$)는 매우 약하여 측정할 수 없었으나, 접착력 향상층 Cr 박막을 삽입하여 $Cr/Al_2O_3$의 계면파괴에너지는 $10.8{\pm}5.5g/mm$를 얻었다. $Al_2O_3$ 표면에 $0.123W/cm^2$ 의 power density로 2분간 $Ar^+$ RF 플라즈마 전처리를 하고 Cr박막을 삽입한 $Cr/Al_2O_3$ 계면파괴에너지는 $39.8{\pm}3.2g/mm$으로 매우 크게 증가하였는데, 이는 $Ar^+$ RF 플라즈마 전처리에 따른 mechanical interlocking효과와 Cr-O 화학결합 효과가 동시에 기여한 것으로 생각된다.

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A New Strategy to Fabricate a Colloidal Array Templated $TiO_2$ Photoelectrode for Dye-sensitized Solar Cells

  • 이현정
    • 한국재료학회:학술대회논문집
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    • 한국재료학회 2011년도 춘계학술발표대회
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    • pp.8.1-8.1
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    • 2011
  • Nanocrystalline titanium dioxide ($TiO_2$) materials have been widely used as an electron collector in DSSC. This is required to have an extremely high porosity and surface area such that the dye can be sufficiently adsorbed and be electronically interconnected, resulting in the generation of a high photocurrent within cells. In particular, their geometrical structures and crystalline phase have been extensively investigated as important issues in improving its photovoltaic efficiency. In this study, we present a new strategy to fabricate a photoelectrode having a periodic structured $TiO_2$ film templated from 1D or 3D polystyrene (PS) microspheres array. Monodisperse PS spheres of various radiuses were used for colloidal array on FTO glasses and two types of photoelectrode structures with different $TiO_2$ materials were investigated respectively. One is the igloo-shaped electrode prepared by $TiO_2$ deposition by RF-sputtering onto 2D microsphere-templated substrates. At the interface between the film and substrate, there are voids formed by the decomposition of PS microspheres during the calcination step. These holes might be expected to play the predominant roles as scattering spherical voids to promote a light harvesting effect, a spacious structure for electrolytes with higher viscosity and effective paths for electron transfer. Additionally the nanocrystalline $TiO_2$ phase prepared by the RF-sputtering method was previously reported to improve the electron drift mobility within $TiO_2$ electrodes. This yields solar cells with a cell efficiency of 2.45% or more at AM 1.5 illumination, which is a very remarkable result, considering its $TiO_2$ electrode thickness (<2 ${\mu}m$). This study can be expanded to obtain higher cell efficiency by higher dye loading through the increase of surface area or multi-layered stacking. The other is the inverse opal photonic crystal electrode prepared by titania particles infusion within 3D colloidal arrays. To obtain the enlargement of ordered area and high quality of crystallinity, the synthesis of titania particles coated with a organic thin layer were applied instead of sol-gel process using the $TiO_2$ precursors. They were dispersed so well in most solvents without aggregates and infused successfully within colloidal array structures. This ordered mesoporous structure provides the large surface area leading to the enough adsorption of dye molecules and have an light harvesting effect due to the photonic band gap properties (back-and-forth reflection effects within structures). A major advantage of this colloidal array template method is that the pore size and its distribution within $TiO_2$ photoelectrodes are determined by those of latex beads, which can be controlled easily. These materials may have promising potentials for future applications of membrane, sensor and so on as well as solar cells.

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A Novel Approach for Controlling Process Uniformity with a Large Area VHF Source for Solar Applications

  • Tanaka, T.
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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    • pp.146-147
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    • 2011
  • Processing a large area substrate for liquid crystal display (LCD) or solar panel applications in a capacitively coupled plasma (CCP) reactor is becoming increasingly challenging because of the size of the substrate size is no longer negligible compared to the wavelength of the applied radio frequency (RF) power. The situation is even worse when the driving frequency is increased to the Very High Frequency (VHF) range. When the substrate size is still smaller than 1/8 of the wavelength, one can obtain reasonably uniform process results by utilizing with methods such as tailoring the precursor gas distribution by adjustingthrough shower head hole distribution or hole size modification, locally adjusting the distance between the substrate and the electrode, and shaping shower head holes to modulate the hollow cathode effect modifying theand plasma density distribution by shaping shower head holes to adjust the follow cathode effect. At higher frequencies, such as 40 MHz for Gen 8.5 (2.2 m${\times}$2.6 m substrate), these methods are not effective, because the substrate is large enough that first node of the standing wave appears within the substrate. In such a case, the plasma discharge cannot be sustained at the node and results in an extremely non-uniform process. At Applied Materials, we have studied several methods of modifying the standing wave pattern to adjusting improve process non-uniformity for a Gen 8.5 size CCP reactor operating in the VHF range. First, we used magnetic materials (ferrite) to modify wave propagation. We placed ferrite blocks along two opposing edges of the powered electrode. This changes the boundary condition for electro-magnetic waves, and as a result, the standing wave pattern is significantly stretched towards the ferrite lined edges. In conjunction with a phase modulation technique, we have seen improvement in process uniformity. Another method involves feeding 40 MHz from four feed points near the four corners of the electrode. The phase between each feed points are dynamically adjusted to modify the resulting interference pattern, which in turn modulate the plasma distribution in time and affect the process uniformity. We achieved process uniformity of <20% with this method. A third method involves using two frequencies. In this case 40 MHz is used in a supplementary manner to improve the performance of 13 MHz process. Even at 13 MHz, the RF electric field falls off around the corners and edges on a Gen 8.5 substrate. Although, the conventional methods mentioned above improve the uniformity, they have limitations, and they cannot compensate especially as the applied power is increased, which causes the wavelength becomes shorter. 40 MHz is used to overcome such limitations. 13 MHz is applied at the center, and 40 MHz at the four corners. By modulating the interference between the signals from the four feed points, we found that 40 MHz power is preferentially channeled towards the edges and corners. We will discuss an innovative method of controlling 40 MHz to achieve this effect.

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Evaluations of Si based ternary anode materials by using RF/DC magnetron sputtering for lithium ion batteries

  • 황창묵;박종완
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2010년도 제39회 하계학술대회 초록집
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    • pp.302-303
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    • 2010
  • Generally, the high energy lithium ion batteries depend intimately on the high capacity of electrode materials. For anode materials, the capacity of commercial graphite is unlike to increase much further due to its lower theoretical capacity of 372 mAhg-1. To improve upon graphite-based negative electrode materials for Li-ion rechargeable batteries, alternative anode materials with higher capacity are needed. Therefore, some metal anodes with high theoretic capacity, such as Si, Sn, Ge, Al, and Sb have been studied extensively. This work focuses on ternary Si-M1-M2 composite system, where M1 is Ge that alloys with Li, which has good cyclability and high specific capacity and M2 is Mo that does not alloy with Li. The Si shows the highest gravimetric capacity (up to 4000mAhg-1 for Li21Si5). Although Si is the most promising of the next generation anodes, it undergoes a large volume change during lithium insertion and extraction. It results in pulverization of the Si and loss of electrical contact between the Si and the current collector during the lithiation and delithiation. Thus, its capacity fades rapidly during cycling. Si thin film is more resistant to fracture than bulk Si because the film is firmly attached to the substrate. Thus, Si film could achieve good cycleability as well as high capacity. To improve the cycle performance of Si, Suzuki et al. prepared two components active (Si)-active(Sn, like Ge) elements film by vacuum deposition, where Sn particles dispersed homogeneously in the Si matrix. This film showed excellent rate capability than pure Si thin film. In this work, second element, Ge shows also high capacity (about 2500mAhg-1 for Li21Ge5) and has good cyclability although it undergoes a large volume change likewise Si. But only Ge does not use the anode due to its costs. Therefore, the electrode should be consisted of moderately Ge contents. Third element, Mo is an element that does not alloys with Li such as Co, Cr, Fe, Mn, Ni, V, Zr. In our previous research work, we have fabricated Si-Mo (active-inactive elements) composite negative electrodes by using RF/DC magnetron sputtering method. The electrodes showed excellent cycle characteristics. The Mo-silicide (inert matrix) dispersed homogeneously in the Si matrix and prevents the active material from aggregating. However, the thicker film than $3\;{\mu}m$ with high Mo contents showed poor cycling performance, which was attributed to the internal stress related to thickness. In order to deal with the large volume expansion of Si anode, great efforts were paid on material design. One of the effective ways is to find suitably three-elements (Si-Ge-Mo) contents. In this study, the Si based composites of 45~65 Si at.% and 23~43 Ge at.%, and 12~32 Mo at.% are evaluated the electrochemical characteristics and cycle performances as an anode. Results from six different compositions of Si-Ge-Mo are presented compared to only the Si and Ge negative electrodes.

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Plasma Sheath Monitoring Sensor 데이터를 활용한 질소이온 상태예측 모형의 기계학습 (Efficient Multicasting Mechanism for Mobile Computing Environment Machine learning Model to estimate Nitrogen Ion State using Traingng Data from Plasma Sheath Monitoring Sensor)

  • 정희진;유진승;정민중
    • 한국정보통신학회:학술대회논문집
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    • 한국정보통신학회 2022년도 춘계학술대회
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    • pp.27-30
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    • 2022
  • 기존의 공정방식에 비해 효율성이나 환경적 면에서 많은 장점을 가진 플라즈마 공정은 반도체 제작에서 널리 사용되고 있다. Plasma Sheath란 플라즈마 bulk와 그 것을 둘러싸고 있는 챔버 벽면과 전극 사이에서 관찰되는 어두운 영역으로 양이온과 전자의 이동속도 차이로 인해 발생한다. Plasma Sheath Monitoring Sensor (PSMS)는 플라즈마와 전극 사이의 전압(Voltage) 차이와 전극에 걸리는 RF power 등을 실시간으로 측정하는 센서로서 플라즈마 챔버 내에서 플라즈마의 상태와 매우 상관도가 높을 것으로 기대된다. 본 연구에서는 PSMS 데이터를 활용하여 플라즈마 챔버 내의 질소이온의 상태를 예측하는 모형을 딥러닝 기계학습 기법을 이용하여 구축하였다. 연구에 사용된 데이터는 파워와 압력을 달리 셋팅한 실험에서 측정된 PSMS 데이터를 학습데이터로 활용하고 플라즈마 bulk와 Si substrate에서 측정된 질소 이온의 비율, 플럭스, 밀도를 레이블로 활용하였다. 본 연구의 결과는 향후 플라즈마 공정의 최적화 및 실시간 정밀제어를 위한 인공지능 기술의 기초가 될 것으로 기대된다.

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Cylindrical Magnetron을 사용한 실리콘의 반응성 이온 건식식각의 특성에 관한 연구 (A Study on the Characterisitics of Reactive Ion Etching)

  • 염근영
    • 한국재료학회지
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    • 제3권4호
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    • pp.327-335
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    • 1993
  • Helmholz구성을 가진 두개의 전자석에 의해 작동되는 RF cylindrical magnetron을 사용하여 이의 플리즈마 성질을 가한 자장의 함수로 조사하고, 또한 $CHF_3$$CF_4/H_2$를 3mTorr의 낮은 압력하에서 사용하여 실리콘의 반응성 이온 건식식각 특성을 조사하였다. 또한 여러 자장의 크기 및 개스 분위기하에서 식각한 실리콘으로 제조한 Schottky다이오드의 전류-전압 특성으로 식각으로 인한 실리콘의 손상정도를 측정하였다. Cylindrical magnetron에 가한 자장을 증가시킴에 따라 플라즈마내이온밀도 및 분해될 개스밀도(radical density)가 직선적으로 증가하였으며 시편이 위치한 전극에 유도되는 직류 자기 바이아스 전압(dc self-bais voltage)은, 반면, 지수적인 감소를 하였다. 100Gauss부근의 자장을 가한 경우에 최대의 식각속도를 갖고 이때의 실리콘의 식각속도가 자장을 가하지 않은 경우에 비해서 5배정도로 증가하였으며, 전지적인 특성 역시 습식방법을 사용하여 식각한 실리콘에 가까운 정도의 이온 손상이 없느 식각상태를 얻을 수 있었다.

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레이저 이온화 이온트랩 질량분석법을 이용한 금속 및 세라믹 시료의 원소분석에 관한 연구 (Study on elemental analysis of metal and ceramic samples by using laser ablation ion trap mass spectrometry(LAITMS))

  • 송규석;박현국;차형기;이상천
    • 분석과학
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    • 제15권1호
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    • pp.7-14
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    • 2002
  • 본 연구에서는 레이저 애블레이션 이온 트랩 질량분석법을 이용하여 금속 및 세라믹 시료들에 대한 원소분석을 수행하였고, 이때 이온화 장치로는 XeCI 엑시머 레이저를 사용하였고 검출장치로서 이온트랩 질량 분석기를 사용하였다. 시료는 트랩의 바깥에 장착하여 시료의 교환이 매우 쉽도록 하였고 고체시료의 분석에 있어서 매우 효과적임을 밝혔다. 헬륨기체의 압력이나 이온저장시간, 초기질량제한 RF 전압 등에 대한 기초 실험을 통하여 실험의 최적 조건을 구하였고 (헬륨 기체압력 $1{\times}10^{-4}$ Torr 이온 저장시간 100 ms 초기 질량 제한전압 $1150V_{p-p}$), 이 결과를 토대로 금속시료(구리, 몰리브데늄)와 세라믹 시료(알루미나 세라믹, 지르코니아 세라믹) 들에 대한 원소분석을 수행하였다.

DC/RF Magnetron Sputtering deposition법에 의한 $TiSi_2$ 박막의 특성연구

  • 이세준;김두수;성규석;정웅;김득영;홍종성
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 1999년도 제17회 학술발표회 논문개요집
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    • pp.163-163
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    • 1999
  • MOSFET, MESFET 그리고 MODFET는 Logic ULSIs, high speed ICs, RF MMICs 등에서 중요한 역할을 하고 있으며, 그것의 gate electrode, contact, interconnect 등의 물질로는 refractory metal을 이용한 CoSi2, MoSi2, TaSi2, PtSi2, TiSi2 등의 효과를 얻어내고 있다. 그중 TiSi2는 비저항이 가장 낮고, 열적 안정도가 좋으며 SAG process가 가능하므로 simpler alignment process, higher transconductance, lower source resistance 등의 장점을 동시에 만족시키고 있다. 최근 소자차원이 scale down 됨에 따라 TiSi2의 silicidation 과정에서 C49 TiSi2 phase(high resistivity, thermally unstable phase, larger grain size, base centered orthorhombic structure)의 출현과 그것을 제거하기 위한 노력이 큰 issue로 떠오르고 있다. 여러 연구 결과에 따르면 PAI(Pre-amorphization zimplantation), HTS(High Temperature Sputtering) process, Mo(Molybedenum) implasntation 등이 C49를 bypass시키고 C54 TiSi2 phase(lowest resistivity, thermally stable phase, smaller grain size, face centered orthorhombic structure)로의 transformation temperature를 줄일 수 있는 가장 효과적인 방법으로 제안되고 있지만, 아직 그 문제가 완전히 해결되지 않은 상태이며 C54 nucleation에 대한 physical mechanism을 밝히진 못하고 있다. 본 연구에서는 증착 시 기판온도의 변화(400~75$0^{\circ}C$)에 따라 silicon 위에 DC/RF magnetron sputtering 방식으로 Ti/Si film을 각각 제작하였다. 제작된 시료는 N2 분위기에서 30~120초 동안 500~85$0^{\circ}C$의 온도변화에 따라 RTA법으로 각각 one step annealing 하였다. 또한 Al을 cosputtering함으로써 Al impurity의 존재에 따른 영향을 동시에 고려해 보았다. 제작된 시료의 분석을 위해 phase transformation을 XRD로, microstructure를 TEM으로, surface topography는 SEM으로, surface microroughness는 AFM으로 측정하였으며 sheet resistance는 4-point probe로 측정하였다. 분석된 결과를 보면, 고온에서 제작된 박막에서의 C54 phase transformation temperature가 감소하는 것이 관측되었으며, Al impuritydmlwhswork 낮은온도에서의 C54 TiSi2 형성을 돕는다는 것을 알 수 있었다. 본 연구에서는 결론적으로, 고온에서 증착된 박막으로부터 열적으로 안정된 phase의 낮은 resistivity를 갖는 C54 TiSi2 형성을 보다 낮은 온도에서 one-step RTA를 통해 얻을 수 있다는 결과와 Al impurity가 존재함으로써 얻어지는 thermal budget의 효과, 그리고 그로부터 기대할 수 있는 여러 장점들을 보고하고자 한다.

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RF 고전력 스트레스에 의한 SAW Device의 고장메카니즘 분석 (Failure Mechanism Analysis of SAW Device under RF High Power Stress)

  • 김영구;김태홍
    • 한국인터넷방송통신학회논문지
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    • 제14권5호
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    • pp.215-221
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    • 2014
  • 본 논문에서는 RF 고전력 스트레스에 의한 SAW 디바이스의 신뢰성 분석을 위하여 향상된 내전력 시험시스템 및 시험방법을 제안하고 고장분석을 통해 고장메카니즘을 분석하였다. 광학현미경, SEM(Scanning Electron Microscope) 및 EDX(Energy Dispersive X-ray Spectro-scopy)장비를 이용하여 고장 분석한 결과, SAW 디바이스의 고장메카니즘은 고전류 밀도 및 고온 조건에서 줄열에 의한 Electromigration으로 분석하였다. Electromigration은 IDT전극에 void와 hillock을 생성하고, 그 결과로 전극이 단락과 단선되어 삽입손실이 증가하는 것이다. 제안된 내전력 시험시스템과 방법을 이용하여 450MHz CDMA용 SAW 필터의 가속수명시험을 수행하고, 아이링 모델과 와이블 분포를 이용하여 SAW 필터의 $B_{10}$수명은 98,500시간으로 추정하였다.

RF Sputtering으로 제작한 $SiO_2 $$SiO_2/TiN$ 박막의 R-V 특성 (The R-V Characteristics of $SiO_2 $ & $SiO_2/TiN$ Thin Film Fabricated by RF Sputtering)

  • 김창석;하충기;김병인
    • 한국전기전자재료학회논문지
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    • 제11권10호
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    • pp.826-832
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    • 1998
  • In this study the thin films with the structure of Si+SiO$_2$+TiN are made by RF supttering method. TiN, which has small diffusion coefficient and low resistivity, is evaporated between SiO$_2$ and Al layers. It investigates the V-R characteristics depending on the thickness of SiO$_2$ which is used as insulation layer and researches its effects on voltage stability of thin film and varistor. These films show very small resistance valus in negative(-) voltage and large and large value in positive voltage band, and with the increase of voltage, resistance value is rapidly reduced and the satisfactory characteristic of varistor is shown at +1[V]. It is found that resistance value of TiN thin film is small and also TiN thin film has more current than the thin film which is not evaporated by TiN thin film. When Al electrode is evaporated of SiO$_2$ thin film, spiking occurs, but the spiking can be prevented with evaporation of TiN between SiO$_2$ and Al layers and this thin films in made easily because of its good attachment. With the increase of voltage, the resistance is changed into non-linear pattern and the bidirectional varistor characteristic is shown and then its theory can be verified by this experiment. Accordingly, when TiN is evaporated of Si Wafer(n-100), it obtains better voltage-resistance than thin film which is not evaporated and also when varistor character is used electrically to automatic control element such as elimination of flame, power distribution arrestor and constant voltage compensation, satisfactory reproducibilities are expected.

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