• 한국표면공학회지
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• 제29권6호
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• pp.773-780
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• 1996

Silicon oxide films were prepared by using five kinds of organosilicon compound as gas sources without oxygen by rf plasma-enhanced CVD (PECVD). UV light was irradiated on a substrate vertically during deposition to enhance film oxidation and ablation of carbon contamination in a deposited films. Films prepared with UV irradiation contained less carbon than those prepared without UV irradiation. The oxidation of the films was improved by UN irradiation. The effect of UV irradiation was, however, not observed when the films were prepared with tetramethy lsilane (TMS) which contained no oxygen atom. Dissociated oxygen atoms from an organosilicon compound were excited in the plasma with UV irradiation around the substrate surface and affected the enhancement of film oxidation and ablation of carbon in the films.

• 한국전기전자재료학회논문지
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• 제11권8호
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• pp.607-612
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• 1998

RF HPCVD(Helicon Plasma Chemical Vapor Deposition) has been successfully constructed for diamond thin films. The system consists of plasma generation tube, deposition chamber, pumping lines for gas system. A mixture of $CH_4 and H_2$is used for reaction. Two thermocouples, a quartz tube surrounded by a RF antenna and a magnet, and a high temperature heater were set up in the deposition chamber. The process for the thin film diamond deposition has been carried put in a high vacuum system at a substrate temperature of $800^{\circ}C$, and pressure of 5 mtorr. It is also demonstrated. that the RF HPCVD system has advantages for controlling deposition parameters easily.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2011년도 추계학술대회
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• pp.886-887
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• 2011

투명전극을 제작하기 위해서 SiOC 절연막 위에 AZO박막을 증착하였다. AZO 박막은 rf power가 5~200W인 RF 마그네트론 스퍼터 방법에 의해서 제작되었다. SiOC 박막은 산소와 DMDMOS 전구체의 유량비를 다르게 하여 플라즈마 발생 화학적 기상 증착방법으로 증착되었다. 증착된 SiOC박막은 UV visible spectroscopy에 의해서 분석하였다. 투명전극의 비저항은 rf 전력이 작을 수록 낮았으며, SiOC 절연막 위에 AZO를 증착시킨 후 반사률은 반대로 바뀌는 것을 확인하였다.

• 한국표면공학회지
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• 제29권6호
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• pp.781-787
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• 1996

Silicom oxide films with good water repellency were prepared by rf plasma-enhanced CVD (rf-PECVD) using four kinds of organosilicon compound, which had different number of methyl ($CH_3$) groups, and oxygen as gas sources. The differences in the deposition rates, film composition and film properties were studied in detail. Water repellency depended on the number of $CH_3$ groups in the organosilicon compounds and the partial pressure of oxygen in the plasma. The highest contact angle for water drops, about 95 degrees, was obtained when trimethy lmethoxy silane (TMMOS) was used. The contact angle decreased with the amount of oxygen gas introduced into the plasma. The dissociation of $CH_3$ groups by adding oxygen was comfirmed by Fourier transform infrared spectroscopy(FTIR) and X-ray photoelectron spectroscopy (XPS). The optical properties were estimated by double-beam spectroscopy and ellipsometry. The transmittance of the glass plate coated by the film prepared with tetramethoxy silane (TMOS) was about 90% and the refractive index of film was 1.44. This value was smaller than the refractive index of a glass plate(soda lime glass, refractive index is 1.515) and this film played a role of anti-refractive coating.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.116-116
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• 2011

오늘날 표시장치는 경량, 고밀도, 고해상도 대면적화의 요구에 의해 TFT-LCD의 발전이 이루어졌다. TFT에는 반도체 재료로서, Poly-Si을 사용하는 Poly-Si TFT와 a-Si:H를 이용하는 a-Si;H TFT가 있는데 a-Si는 $350^{\circ}C$ 이하의 저온으로 제작이 가능하여 많이 사용되고 있다. 이러한 방향에 맞추어 bottom gate 구조의 a-Si TFT 실험을 진행하였다. P-type silicon substrate ($0.01{\sim}0.02{\Omega}-cm$)에 gate insulator 층인 SiNx (SiH4 : NH3 = 6:60)를 200nm 증착하였다. 그리고 그 위에 active layer 층인 a-Si (SiH4 : H2 : He =2.6 : 10 : 100)을 다른 RF power를 적용하여 100 nm 증착하였다. 그 위에 Source와 Drain 층은 Al 120 nm를 evaporator로 증착하였다. active layer, gate insulator 층은 ICP-CVD 장비를 이용하여 증착하였으며, 공정온도는 $300^{\circ}C$ 로 고정하였다. active layer층 증착시 RF power는 100W, 300W, 500W, 600W로 가변하였고, width/length는 100 um/8um로 고정하였다. 증착한 a-Si layer층을 Raman spectroscope, SEM 측정 하였으며, TFT 제작 후, VG-ID, VD-ID 측정을 통해 전기적 특성인 Threshold voltage, Subthreshold swing, Field effect mobility, ON/OFF current ratio를 비교해 보았다.

• 한국결정성장학회지
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• 제14권1호
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• pp.6-11
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• 2004

Bias 인가된 hot filament CVD 방법을 이용해 티타늄을 RF sputtering 법으로 고속도강에 피복하여 중간 층으로 한 후 다이아몬드 박막을 피복할 때 bias 전압의 영향과 계면 층의 특성을 조사하였다. 다이아몬드 증착 시 bias가 인가될 경우 필라멘트에서 전자 방출이 촉진되어 다이아몬드 핵생성과 성장을 촉진시켰으며 본 실험에서의 최적 증착 조건은 증착 압력 20 torr, bias 인가전압 200V, 기판온도 $700^{\circ}C$로 나타났다. 강에의 다이아몬드 박막 형성 시 중간 층으로서의 티타늄은 Fe 및 C에 대한 확산도가 높고 탄화물 형성 원소이므로 다이아몬드 핵생성 및 성장에 적합한 원소로 나타났다.

• JSTS:Journal of Semiconductor Technology and Science
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• 제11권3호
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• pp.135-145
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• 2011

Accurate process characterization and optimization are the first step for a successful advanced process control (APC), and they should be followed by continuous monitoring and control in order to run manufacturing processes most efficiently. In this paper, process characterization and recipe optimization methods with multiple outputs are presented in high density plasma-chemical vapor deposition (HDP-CVD) silicon dioxide deposition process. Five controllable process variables of Top $SiH_4$, Bottom $SiH_4$, $O_2$, Top RF Power, and Bottom RF Power, and two responses of interest, such as deposition rate and uniformity, are simultaneously considered employing both statistical response surface methodology (RSM) and neural networks (NNs) based genetic algorithm (GA). Statistically, two phases of experimental design was performed, and the established statistical models were optimized using performance index (PI). Artificial intelligently, NN process model with two outputs were established, and recipe synthesis was performed employing GA. Statistical RSM offers minimum numbers of experiment to build regression models and response surface models, but the analysis of the data need to satisfy underlying assumption and statistical data analysis capability. NN based-GA does not require any underlying assumption for data modeling; however, the selection of the input data for the model establishment is important for accurate model construction. Both statistical and artificial intelligent methods suggest competitive characterization and optimization results in HDP-CVD $SiO_2$ deposition process, and the NN based-GA method showed 26% uniformity improvement with 36% less $SiH_4$ gas usage yielding 20.8 ${\AA}/sec$ deposition rate.

• 대한전기학회논문지:전기물성ㆍ응용부문C
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• 제54권2호
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• pp.63-68
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• 2005

Total 12 units of high power klystron-modulator systems as microwave source are under operation for 2.5 GeV electron linear accelerator in Pohang Light Source (PLS) linac. The klystron-modulator system has an important role for the stable operation to improve an availability statistics of overall system performance of klystron-modulator system. RF power and beam power of klystron are precisely measured for the effective control of electron beam. A precise measurement and measurement equipment with good response characteristics are demanded for this. Input power of klystron is calculated from the applied voltage and the current on its cathode. Tiny measurement error severely effects RF output power value of klystron. Therefore, special care is needed to measure precise beam voltage. Capacitive voltage divider (CVD), which divides input voltage as capacitance ratio, is intended for the measurement of a beam voltage of 400 kV generated from the klystron-modulator system. Main parameter to determine standard capacitance in the high arm of CVD is dielectric constant of insulation oil. Therefore CVD should be designed to have a minimum capacitance variation due to voltage, frequency and temperature in the measurement range. This paper will be present and discuss the design concept and analysis of capacitive voltage divider for a pulsed high-voltage measurement, and the empirical relations between capacitance effects and oil temperature variation.

• 한국결정성장학회지
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• 제10권1호
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• pp.5-12
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• 2000

Silicon carbide(SiC)는 뛰어난 전기적, 열적, 물리적 특성 때문에 내환경 전자소자용 반도체 재료로 널리 연구되고 있다. 본 연구에서는 화학기상증착법으로 단결정 6H-SiC 동종박막을 성장시키고 이의 성장 특성을 조사하였다. 특히, 몰리브덴 (Mo)-plate를 이용하여 SiC를 코팅하지 않은 graphite susceptor를 사용한 6H-SiC 동종박막 성장조건을 성공적으로 얻었다. 대기압 상태의 RF-유도가열식 챔버에서 CVD성장을 수행하였고, <1120> 방향으로 $3.5^{\circ}$off-axis된 기판을 사용하였다. 성장 박막의 결정성을 평가하기 위하여 Nomarski 관찰, 투과율 측정 , 라만 분광, XRD, 광발광(PL) 분광, 투과전자현미경(TEM) 측 정 등의 방법을 이용하였다. 이상과 같은 실험을 통하여, 본 연구에서는 성장온도 $1500^{\circ}C$, C/Si flow ratio ($C_3H_8$ 0.2 sccm, $SiH_4$ 0.3 sccm)인 성장조건에서 결정성이 가장 좋은 6H-SiC 동종박막을 얻을 수 있었다.

• 마이크로전자및패키징학회지
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• 제14권3호
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• pp.15-20
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• 2007

플라스틱 기판에 적용이 가능한 최대 공정온도 $270^{\circ}C$ 이하에서 ZnO-TFT 소자를 제작하였다. ZnO-TFT 소자는 bottom gate 구조로 제작되었으며, ICP-CVD로 형성된 $SiO_2$ 산화물 게이트 공정을 제외하고는 모든 박막증착 공정은 RF-magnetron sputtering process를 이용하였다. ZnO 박막은 Ar과 $O_2$ gas 유량의 비율에 따라 여러 가지 조건에서 RF-magnetron sputtering 시스템을 이용하여 상온에서 증착하였다. Ar과 $O_2$ gas의 비율에 따라 제작된 TFT 소자는 모두 enhancement 모드의 소자특성을 나타내었고, 또한 가시광선영역에 있어 80% 이상의 높은 투과율을 보였다. ZnO 증착시 순수 Ar을 사용하여 제작된 ZnO-TFT의 경우에, $1.2\;cm^2/Vs$의 field effect mobility, 8.5 V의 threshold voltage, 그리고 $5{\times}10^5$의 높은 on/off ratio, 1.86 V/decade의 swing voltage로 가장 우수한 전기적 특성을 보였다.