• KIEE International Transactions on Electrophysics and Applications
• /
• 제4C권5호
• /
• pp.220-229
• /
• 2004

We have examined a technique of one-dimensional (1D) fluid modeling for radio-frequency Ar capacitively coupled plasmas (CCP) between unequal-sized powered and grounded electrodes. In order to simulate a practical CCP reactor configuration with a grounded side wall by the 1D model, it has been assumed that the discharge space has a conic frustum shape; the grounded electrode is larger than the powered one and the discharge space expands with the distance from the powered electrode. In this paper, we focus on how much a 1D model can approximate a 2D model and evaluate their comparisons. The plasma density calculated by the 1D model has been compared with that by a two-dimensional (2D) fluid model, and a qualitative agreement between them has been obtained. In addition, 1D and 2D calculation results for another reactor configuration with equal-sized electrodes have also been presented together for comparison. In the discussion, four CCP models, which are 1D and 2D models with symmetric and asymmetric geometries, are compared with each other and the DC self-bias voltage has been focused on as a characteristic property that reflects the unequal electrode surface areas. Reactor configuration and experimental parameters, which the self-bias depends on, have been investigated to develop the ID modeling for reactor geometry with unequal-sized electrodes.

• JSTS:Journal of Semiconductor Technology and Science
• /
• 제4권2호
• /
• pp.83-87
• /
• 2004

Phase noise performance and current consumption of Radio Frequency (RF) Voltage-Controlled Oscillator (VCO) are largely dependent on the Quality (Q) factor of inductor-capacitor (LC) tank. Because the Q-factor of LC tank is determined by on-chip spiral inductor, we designed, analyzed, and modeled on-chip differential inductor to enhance differential Q-factor, reduce current consumption and save silicon area. The simulated inductance is 3.3 nH and Q-factor is 15 at 2 GHz. Self-resonance frequency is as high as 13 GHz. To verify its use to RF applications, we designed 2 GHz differential LC VCO. The measurement result of phase noise is -112 dBc/Hz at an offset frequency of 100 kHz from a 2GHz carrier frequency. Tuning range is about 500 MHz (25%), and current consumption varies from 5mA to 8.4 mA using bias control technique. Implemented in $0.35-{\mu}m$ SiGe BiCMOS technology, the VCO occupies $400\;um{\times}800\;um$ of silicon area.

• 대한전자공학회논문지SD
• /
• 제41권12호
• /
• pp.27-34
• /
• 2004

최근 실리콘 미세공정의 발달로 상용화된 0.2$\mum$ 게이트길이 이하의 deep submicron MOSFET 출력특성을 정확히 모델링하기 위해서는 RF 기판 회로 연구가 필수적이다. 먼저 본 논문에서는 기판 캐패시던스와 기판 저항이 병렬로 연결된 모델과 기판 저항만을 사용한 단순 모델들에 적합한 직접 추출 방법을 각각 개발하였다. 이 추출방법들을 0.15$\mum$ CMOS 소자에 적용한 결과 단순 모델보다 RC 병렬 기판모델이 측정된 $Y_{22}$-parameter에 30GHz까지 더 잘 일치하는 것을 확인하였으며, 이는 RC 병렬 기판모델 및 직접추출방법의 RF 정확도를 증명한다. 이러한 RC 병렬 기판모델을 사용하여 게이트 길이를 0.11에서 0.5$\mum$까지 변화시키고 드레인 전압을 0에서 1.2V까지 증가시키면서 기판 모델 파라미터들의 bias 종속 특성과 게이트 길이 종속 특성을 새롭게 추출하였다. 이러한 새로운 추출 결과는 scalable한 RF 비선형 기판 모델 개발에 유용하게 사용될 것이다.

• 한국항해항만학회지
• /
• 제28권3호
• /
• pp.213-219
• /
• 2004

본 논문에서는 1,452∼l,492 MHz L-Band 대역의 위성 DAB 수신기를 위한 저잡음증폭기를 입ㆍ출력 반사계수와 전압정재파비를 개선하기 위하여 평형증폭기 형태로 설계 및 제작하였다. 저 잡음증폭기는 GaAs FET소자인 ATF-10136을 사용한 저 잡음증폭단과 MMIC 소자인 VNA-25을 사용한 이득증폭단을 하이브리드 방식으로 구성하였으며, 최적의 바이어스를 인가하기 위하여 능동 바이어스 회로를 사용하였다. 적용된 능동 바이어스 회로는 소자의 펀치오프전압($V_P$)과 포화드래인 전류($I_{DSS}$)의 변화에 따라 주어진 바이어스 조건을 만족시키기 위해 소스 저항과 드래인 저항의 조절이 필요없다. 즉, 능동 바이어스 회로는 요구된 드래인 전류와 전압을 공급하기 위해 게이트-소스 전압($V_{gs}$)을 자동적으로 조절한다. 저잡음증폭기는 바이어스 회로와 RF 회로를 FR-4기판 위에 제작하였고, 알류미늄 기구물에 장착하였다. 제작된 저잡음증폭기는 이득 32 dB, 이득평탄도 0.2 dB, 0,95 dB 이하의 잡음지수, 입ㆍ출력 전압정재파비는 각각 1.28, 1.43이고, $P_{1dB}$ 는 13 dBm으로 측정되었다.

• 한국세라믹학회지
• /
• 제39권2호
• /
• pp.171-177
• /
• 2002

본 연구에서는 DC bias가 인가된 유도결합형 플라즈마 열선 화학기상증착법을 이용하여 580$^{\circ}C$의 저온에서 탄소나노튜브를 수직 배향시켰다. 성장된 탄소나노튜브의 기판으로는 강화유리 위에 촉매층으로 Ni과 전도층으로 Cr을 300/200 ${\AA}$(Ni/Cr) 증착된 것으로 R-F magnetron sputtering을 이용하여 제작하였다. 성장 시 RF power와 DC bias power는 150W와 80W이며 텅스텐 필라멘트 power는 7∼8 A로 인가하였다. 성장된 탄소나노튜브는 속이 비어 있는 다중벽으로 이루어 졌으며 성장된 탄소나노튜브 끝단에는 금속 촉매로 보이는 Ni이 존재하는 것을 알 수 있었다. 탄소나노튜브는 흑연화도가 우수하며 그에 따라 탄소나노튜브의 전계 방출 특성도 우수하게 평가되었다. 성장된 탄소나노튜브의 구동 전압은 약 3 V/${\mu}m$이었다.

• 한국전자통신학회논문지
• /
• 제2권1호
• /
• pp.1-9
• /
• 2007

In this paper, a third-order harmonic mixer is designed using frequency multiplier theory for the Ka-band. The gate bias voltage is selected by frequency multiplier theory to maximize the third-order harmonic element ofthe fundamental LO frequency in the proposed mixer. The designed mixer has a gate mixer structure composed of a gate terminal input for the fundamental local signal ($f_{LO}$), RF signal (${RF}$) and a drain terminal output for the harmonic frequency ($3f_{LO}-f_{RF}$) respectively. The Ka-band harmonic mixer is designed and fabricated using a commercial GaAs MESFET device with a plastic package. The proposed mixer will provide a solution for the problems found in the high cost, complex circuitry in a conventional Ka-band mixer. The 33.5 GHz harmonic mixer has a -10 dB conversion gain by pumping 11.5 GHz LO with a +5 dBm level.

• The Korean Journal of Ceramics
• /
• 제4권1호
• /
• pp.9-14
• /
• 1998

Diamond-like carbon(DLC) films were deposited on buffer-layered ZnS substrates by radio frequency plasma enhanced chemical vapor deposition(RF-PECVD) method. Ge and GeC buffer layera were used between DLC and ZnS substrates to promote the adhesion of DLC on ZnS substrates. Ge buffer layers were sputter deposited by RF magnetron sputtering and $GeC^1$ buffer layers were deposited by same method except using acetylene reactive gas. The relatinship between film properties and deposition conditions was investigated using gas pressure, RF power and dc bias voltage as PECVD parameters. The hardness of DLC films were measured by micro Vickers hardness test and the adhesion of DLC films on buffer-layered ZnS substrates were studied by Sebastian V stud pull tester. The optical properties of DLC films on butter-layered ZnS substrates were characterized by ellipsometer and FTIR spectroscopy.

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

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 2000년도 영호남학술대회 논문집
• /
• pp.142-145
• /
• 2000

The performance of ac plasma display panels (PDP) is influenced strongly by the surface glow discharge characteristics on the MgO thin films. This paper deals with the surface glow discharge characteristics and some physical properties of MgO thin films prepared by reactive RF planar unbalanced magnetron sputtering in connection with ac PDP. The samples prepared with the dc bias voltage of -10V showed lower discharge voltage and lower erosion rate by ion bombardment than those samples prepared by conventional magnetron sputtering or E-beam evaporation. The main factor that improves the discharge characteristics by bias voltage is considered to be due to the morphology changes or crystal structure of the MgO thin film by ion bombardment during deposition process.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 E
• /
• pp.2236-2238
• /
• 1999

This paper deals with the surface glow discharge characteristics and some physical properties of MgO thin films prepared by RF unbalanced magnetron sputtering(UBMS) in surface discharge type AC PDP. The minimum discharge voltage is obtained for the sample of substrate holder bias voltage -10V. The main factors that improves the discharge characteristics by applied bias voltage is considered to be due to the morphology changes or crystal structure of the MgO thin film by ion bombardment during deposition process Moreover, the anti-sputtering characteristics of MgO thin film by UBMS is more excellent than that of balanced magnetron sputtering(BMS) and E-beam evaporation method.