• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 하계학술대회 논문집 Vol.5 No.1
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• pp.421-424
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• 2004

As the deep sub-micron devices are recently integrated high package density, novel process method for sub $0.1{\mu}m$ devices is required to get the superior thin gate oxide characteristics and reliability. However, few have reported on the electrical quality and reliability on the thin gate oxide. In this paper I will recommand a novel shallow trench isolation structure for thin gate oxide $30{\AA}$ of deep sub-micron devices. Different from using normal LOCOS technology, novel shallow trench isolation have a unique 'inverse narrow channel effects' when the channel width of the devices is scaled down shallow trench isolation has less encroachment into the active device area. Based on the research, I could confirm the successful fabrication of shallow trench isolation(STI) structure by the SEM, in addition to thermally stable silicide process was achiever. I also obtained the decrease threshold voltage value of the channel edge and the contact resistance of $13.2[\Omega/cont.]$ at $0.3{\times}0.3{\mu}m^2$. The reliability was measured from dielectric breakdown time, shallow trench isolation structure had tile stable value of $25[%]{\sim}90[%]$ more than 55[sec].

• 한국세라믹학회지
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• 제39권9호
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• pp.822-828
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• 2002

$ZrO_2$ 첨가량 변화에 따른 전기적 특성과 고주파 대용량 세라믹 캐패시터 제조공정 조건을 규명하기 위하여 고주파 대용량 세라믹 캐패시터의 제조 및 전기적 특성에 관하여 연구하였다. 단위 캐패시터는 테이프 캐스팅법으로 제조되었으며, 유전체 및 바인더의 최적조성은 57.5∼60.0: 42.5∼40.0 wt%이다. 슬러리의 점도는 4000∼5000 cps이며, 이 슬러리를 사용하여 제조한 그린 테이프는 뛰어난 캐스팅 상태를 유지하고 있다. 80$^{\circ}C$에서 200 kg/$cm^2$의 성형압으로 성형함으로서 최적의 적층 상태를 얻을 수 있었다. 단위 캐패시터의 전기적 특성, 특히 절연파괴 특성을 증진시키기 위하여 $ZrO_2$를 첨가하였다. $ZrO_2$ 첨가량이 1 wt%에서부터 5 wt%까지 첨가한 경우에는 단위 캐패시터의 유전상수 및 유전손실에 큰 영향을 미치지 못하였다. 또한 유전상수도 10 kHz에서 500 kHz 사이의 주파수 범위에서 큰 변호가 없었다. 내전압은 3 wt%를 첨가한 경우 $CaZrO_3$에 형성 및 입자크기 감소로 인하여 증진됨을 확인할 수 있었다.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 D
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• pp.1352-1354
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• 1998

$LiNbO_3$ transistor showed relatively stable characteristic, low interface trap density, and large remanent polarization. This paper reports ferroelectric $LiNbO_3$ thin films grown directly on p-type Si(100) substrates by 13.56 MHz rf magnetron sputtering system for FRAM applications. To take advantage of low temperature requirement for growing films, we deposited $LiNbO_3$ films lower than $300 ^{\circ}C$. RTA(Rapid Thermal Anneal) treatment was performed for as-deposited films in an oxygen atmosphere at $600^{\circ}C$ for 60 sec. We learned from X-ray diffraction that the RTA annealed films were changed from amorphous to poly-crystalline $LiNbO_3$ which exhibited (012), (015), and (022) orientations. The I-V characteristics of $LiNbO_3$ films before and after anneal treatment showed that RTA improved the leakage current of films. The leakage current density of films decreased from $10^{-5}$ to $10^{-7} A/cm^2$ at room temperature measurement. Breakdown electric field of the films exhibited higher than 500 kV/cm. The C-V curves showed the clockwise hysteresis represents ferroelectric switching characteristics. From C-V curves, we calculated dielectric constant of thin film $LiNbO_3$ as 27.5 which is close to that of bulk value.

• 마이크로전자및패키징학회지
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• 제13권2호
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• pp.15-19
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• 2006

이원계 산화막인 비정질 $SiO_2$와 다결정 $TiO_2$의 저항 변화 특성을 연구하였다. Metal-Insulator-Metal의 저항 소자를 형성하여 전압 sweep에 의한 I-V를 측정하여 저항 상태를 확인하였다. 즉, 낮은 저항 상태 (LRS) 와 높은 저항 상태 (HRS) 의 두 가지 저항 상태가 존재하였으며, LRS는 전압에 의한 절연체의 불완전한 breakdown 후에, HRS는 전압에 의한 negative differential resistance 후에 각각 나타났다. LRS의 경우에는 Ohmic 전도 mechanism에 의해서, HRS의 경우에는 Schottky contact에 의한 potential barrier의 생성이 저항 상태를 결정한다고 제안하였다. 즉, potential barrier의 생성과 소멸이 두 저항 상태를 형성한다고 할 수 있다. 유전율이 높은 $TiO_2$가 $SiO_2$에 비하여, 낮은 동작 특성 전압을 나타내었으며, 1 V에서의 저항비도 높았다.

• The Korean Journal of Ceramics
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• 제6권2호
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• pp.138-142
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• 2000

Thin film $LiNbO_3$MFS (metal-ferroelectric-semiconductor) capacitor showed improved characteristics such as low interface trap density, low interaction with Si substrate, and large remanent polarization. This paper reports ferroelectric $LiNbO_3$thin films grown directly on p-type Si (100) substrates by 13.56 MHz RF magnetron sputtering system for FRAM (ferroelectric random access memory) applications. RTA (rapid thermal anneal) treatment was performed for as-deposited films in an oxygen atmosphere at $600^{\circ}C$ for 60sec. We learned from X-ray diffraction that the RTA treated films were changed from amorphous to poly-crystalline $LiNbO_3$which exhibited (012), (015), (022), and (023) plane. Low temperature film growth and post RTA treatments improved the leakage current of $LiNbO_3$films while keeping other properties almost as same as high substrate temperature grown samples. The leakage current density of $LiNbO_3$films decreased from $10^{-5}$ to $10^{-7}$A/$\textrm{cm}^2$ after RTA treatment. Breakdown electric field of the films exhibited higher than 500 kV/cm. C-V curves showed the clockwise hysteresis which represents ferroelectric switching characteristics. Calculated dielectric constant of thin film $LiNbO_3$illustrated as high as 27.9. From ferroelectric measurement, the remanent polarization and coercive field were achieved as 1.37 $\muC/\textrm{cm}^2$ and 170 kV/cm, respectively.

• 한국정보통신학회논문지
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• 제4권2호
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• pp.297-305
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• 2000

본 논문에서는 다양한 안테나 면적을 가지는 다결정실리콘(poly-Si) 및 폴리사이드(polycide) 게이트 물질을 게이트로 갖는 커패시터 및 n/p-MOS 트랜지스터를 사용하여 AAR(Antenna Area Ratio)의 크기에 따른 플라즈마 피해를 측정 및 분석하였다. 플라즈마 공정에 대한 신뢰도 특성을 조사하기 위해, MOS 소자의 게이트 물질을 달리하여 플라즈마 공정에 대한 초기 특성 및 F-N 스트레스와 hot carrier 스트레스 인가시의 n/p-MOSFET의 열화 특성을 측정한 결과 금속 AR에 의하여 플라즈마 공정의 영향을 받는 것으로 관찰되었다. 폴리사이드 게이트 구조가 다결정실리콘 게이트 구조보다 AAR에 따른 정전류 스트레스 인가시의 TDDB(Time Dependent Dielectric Breakdown)및 게이트 전압의 변화 등과 같은 신뢰성 특성에서 상당히 개선됨을 알 수 있었다. 이는 텅스텐 폴리사이드 형성 공정 중에 불소가 게이트 산화막에 함유되었기 때문인 것으로 설명할 수 있으며, 게이트 물질로 폴리사이드를 사용한 소자에서 플라즈마 영향을 줄일 수 있다는 사실이 차세대 MOS 소자의 게이트 박막으로 폴리사이드 게이트 박막을 활용할 수 있는 가능성을 확인하였다.

• 한국표면공학회지
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• 제29권6호
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• pp.809-815
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• 1996

$Y_2O_3$-based metal-insulator-semiconductor (MIS) structure on p-Si(100) has been studied. Films were prepared by UHV reactive ionized cluster beam deposition (r-ICBD) system. The base pressure of the system was about $1 \times 10^{-9}$ -9/ Torr and the process pressure $2 \times 10^{-5}$ Torr in oxygen ambience. Glancing X-ray diffraction(GXRD) and in-situ reflection high energy electron diffracton(RHEED) analyses were performed to investigate the crystallinity of the films. The results show phase change from amorphous state to crystalline one with increasingqr acceleration voltage and substrate temperature. It is also found that the phase transformation from $Y_2O_3$(111)//Si(100) to $Y_2O_3$(110)//Si(100) in growing directions takes place between $500^{\circ}C$ and $700^{\circ}C$. Especially as acceleration voltage is increased, preferentially oriented crystallinity was increased. Finally under the condition of above substrate temperature $700^{\circ}C$ and acceleration voltage 5kV, the $Y_2O_3$films are found to be grown epitaxially in direction of $Y_2O_3$(1l0)//Si(100) by observation of transmission electron microscope(TEM). Capacitance-voltage and current-voltage measurements were conducted to characterize Al/$Y_2O_3$/Si MIS structure with varying acceleration voltage and substrate temperature. Deposited $Y_2O_3$ films of thickness of nearly 300$\AA$ show that the breakdown field increases to 7~8MV /cm at the same conditon of epitaxial growing. These results also coincide with XPS spectra which indicate better stoichiometric characteristic in the condition of better crystalline one. After oxidation the breakdown field increases to 13MV /cm because the MIS structure contains interface silicon oxide of about 30$\AA$. In this case the dielectric constant of only $Y_2O_3$ layer is found to be $\in$15.6. These results have demonstrated the potential of using yttrium oxide for future VLSI/ULSI gate insulator applications.

• 전기학회논문지
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• 제56권9호
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• pp.1561-1565
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• 2007

According to thermal degradation on power transformers, it is known that electrical, mechanical and chemical characteristics for power transformer's oil-paper are changed. In the chemical property, especially, when the kraft paper is aged, the cellulose polymer chains break down into shorter lengths. It causes decrease in both tensile strength and degree of polymerization of paper insulation. Also the paper breakdown is accompanied by an increase in the content of various furanic compounds within the dielectric liquid. It is known that furanic components in transformer oil come only from the decomposition of insulating paper rather than from the oil itself. Therefore the analysis of furanic degradation products provides a complementary technique to dissolved gas analysis for monitoring transformers when we evaluate the aging of insulating paper by the total concentration of carbon monoxide and carbon dioxide dissolved in oil only. Recently, the analysis of furanic compounds by high performance liquid chromatography(HPLC) using IEC 61198 method for estimating degradation of paper insulation in power transformers has been used more conveniently for assessment of oil-paper. It is know that the main products which is produced by aging are 2-furfuryl alcohol, 2-furaldehyde(furfural), 2-furoic acid, 2-acetylfuran, 5-methyl-2-furaldehyde, and 5-hydroxymethyl-2-furaldehyde. For investigating the accelerated aging process of oil-paper samples we manufactured accelerating aging equipment and we estimated variation of insulations at $140^{\circ}C$ temp. during 500 hours. Typical transformer proportions of copper, silicon steel and iron have been added to oil-paper insulation during the aging process. The oil-paper insulation samples have been measured at intervals of 100 hours. Finally we have analyzed that 2-furoic acid and 2-acetylfuran products of furanic compounds were detected by HPLC, and their concentrations were increased with accelerated aging time.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2011년도 제42회 하계학술대회
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• pp.1564-1565
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• 2011

고온 초전도(HTS) 변압기는 절연수명의 손실 없이 과부하 용량의 증가와 효율의 향상이 가능하여 기존의 변압기와는 달리 구조물의 소형화로 공간 배치가 용이하고 환경 친화적 이어서 전력시스템 운용 전반에 걸쳐 많은 이점을 제공한다. 하지만, 이러한 이점에도 불구하고 AC전압이 인가되었을 때, 교류손실에 의한 심각한 효율의 감소는 불가피하다. 따라서, HTS 변압기뿐만 아니라 고온초전도전력기기들에 대한 DC전압의 적용은 초전도상에서 전기적 저항이 거의 0이라는 큰 이점을 가지고 있기 때문에 초전도 전력기기 시스템에서 최선의 선택으로 여기어지고 있다. 그러므로 DC고온초전도 전력기기들을 개발하기 위해서는 극저온상에서의 DC 절연 특성과 같은 기초연구들이 선행 되어야 한다. 그러나, 지금까지 이 분야에 대한 연구가 많이 부족한 실정이다. 본 논문에서는 현재 초전도 전력기기의 대표적인 절연 매질인 Kraft, Kapton(Polymide)와 Nomax(Type 410)을 가지고 권선대 권선의 형상을 모의하여 DC와 AC의 절연파괴 특성의 차이점을 분석하였다. 실험의 결과로부터, 극저온상에서 각각의 절연매질에 따른 DC와 AC의 절연파괴 특성을 확인할 수 있었다.

• 전기학회논문지
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• 제62권10호
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• pp.1408-1412
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• 2013

High power pulse generating technology is to accumulate the energy for relatively long and then to create a strong force by emitting the energy very fast. High power pulse generating technology has recently been using in various fields like environments, industry, research, military and so on. Numerous studies about high power pulse generators have already been performed and commercialized in various conditions. However, in aspect of their size and weight, it is hard to carry the generators which currently have been developed. For these reasons, din nations like America or Russia, the researches have been performed for Ferroelectric Generators(FEG), which have relatively simple structure and are economical. To realize the ferroelectric generator, in this study, we selected the PZTs which have different physical properties respectively, and then shocked them using explosives. The PZT samples with volumes of $0.31{\sim}0.94cm^3$ were depolarized by shocked and produced the waveform that have peak voltages of 4.28 ~ 15kV. The lowest relative permittivity sample generated much higher peak voltage. And sudden voltage drops which seem to be caused by dielectric breakdown were observed in some experiments using low young's modulus samples. Also, increase in thickness led to increase in peak voltage, but the ratio of the voltage rise did not reach the ration of the thickness increase.