• 한국전기전자재료학회논문지
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• 제18권3호
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• pp.276-283
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• 2005

Magnetic tunneling transistor (MTT) device using the amorphous n-type Si semiconductor film for base and collector consisting of the [CoFe/NiFe](free layer) and Si(top layer) multilayers was used to study the spin-dependent hot electron magnetocurrent (MC) and tunneling magnetoresistance (TMR) at room temperature. A large MC of 40.2 % was observed at the emitter-base bias voltage ( $V_{EB}$ ) of 0.62 V. The increasing emitter hot current and transfer ratio ( $I_{C}$/ $I_{E}$) as $V_{EB}$ are mainly due to a rapid increase of the number of conduction band states in the Si collector. However, above the $V_{EB}$ of 0.62 V, the rapid decrease of MC was observed in amorphous Si-based MTT because of hot electron spin-dependent elastic scattering across CoFe/Si interfaces.

• Journal of Magnetics
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• 제6권4호
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• pp.126-128
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• 2001

The effect of rapid thermal anneal (RTA) has been investigated on the properties of an FeMn exchange-biased magnetic tunnel junction (MTJ) using magnetoresistance and I-V measurements and transmission electron microscopy (TEM). The tunneling magnetoresistance (TMR) in an as-grown MTJ is found to be ∼27%, while the TMR in MTJs annealed by RTA increases with annealing temperature up to 300$\^{C}$, reaching ∼46%. A TEM image reveals a structural change in the interface of A1$_2$O$_3$layer for the MTJ annealed by RTA at 300$\^{C}$. The oxide barrier parameters are found to vary abruptly with annealing time within a few ten seconds. Our results demonstrate that the present RTA enhances the magnetoresistive properties of MTJs.

• 한국자기학회지
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• 제25권2호
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• pp.47-51
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• 2015

이 연구에서는 DC스퍼터링(DC Magnetron Sputtering)방식으로 제작 된 MgO 터널 장벽층을 갖는 자기터널접합을 급속 열처리 방식(Rapid Thermal Annealing)을 이용하여 열처리 공정 중의 구조적, 조성적 변화 및 스핀 수송 특성의 변화를 연구하였다. 본 연구를 통하여 급속 열처리 방식이 기존 일반적인 열처리 방식에 비하여 높은 터널링자기저항비를 얻을 수 있다는 것을 발견하였다. 또한, 열처리 시간의 단축을 통하여 Mn, Ta, Ru 등의 내부물질의 인접한 층으로의 확산을 억제할 수 있다는 것을 알 수 있었다. 유의미한 데이터를 수집하기 위하여 다양한 열처리 온도 조건과 시간조건에서 급속 열처리를 실시 한 후 자기 터널 접합의 전, 자기적 특성을 관찰하였다. 이러한 특성 변화는 향후 보다 우수하고 안정적인 자기적 특성과 열적 안정성을 갖는 자기터널접합 제작을 위해 다양하게 응용될 수 있다고 생각된다.

• 터널과지하공간
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• 제16권3호
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• pp.209-217
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• 2006

터널의 고속굴진을 위한 굴착 및 발파 손상영역을 평가하기 위하여 암반에 대한 파괴역학적 연구 결과들을 조사하고 고찰하였다. 파괴역학을 이용하여 균열의 발생 기구를 확립하고 손상영역을 평가하며 나아가서 균열을 효과적으로 제어하기 위한 시도들이 이루어지고 있으며 그 적용가능성이 높다고 판단된다.

• 융합보안논문지
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• 제15권4호
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• pp.107-112
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• 2015

무선통신기술의 급격한 발달로 인해 상용기술을 접목한 군의 통신 기반체계 또한 무선체계 위주로 변하고 있다. 하지만 군의 통신은 비밀스러운 내용이 많을뿐더러 특히 물리적으로 보안시스템이 불완전한 무선 환경에서는 적의 위협이 더욱더 증가될 것으로 예상된다. 최근 차세대 전술네트워크 통신 시스템이 All IP 기반의 무선체계로 전력화될 예정이다. 본 논문에서는 이러한 무선 환경에서 예상되는 위협요소를 살펴보고 이에 대한 적절한 터널링 기법에 대해 연구해 본다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.13-13
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• 2010

Switching an elementary excitation by injecting a single carrier would offer the exciting opportunity for the ultra-high data storage technologies. However, there has been no methodology available to investigate the interaction of low energy discrete carriers with nano-structures. In order to map out the spatial dependency of such single carrier level interactions, we developed a pulse-and-probe algorithm, combining with low temperature scanning tunneling microscopy. The new tool, which we call single carrier spectroscopy, allows us to track the interaction with the target macrostructure with tunneling carriers on a single carrier basis. Using this tool, we demonstrate that it is possible not only to locally write and erase individual bi-solitons, reliably and reversibly, but also to track of creation yields of single and multiple bi-solitons. Bi-solitons are pairs of solitons that are elementary out-of-phase excitations on anti-ferromagnetically ordered pseudo-spin system of Si dimers on Si(001)-c(42) surfaces. We found that at low energy tunneling the single bisoliton creation mechanism is not correlated with the number of carriers tunneling, but with the production of a potential hole under the tip. An electric field at the surface determines the density of the local charge density under the tip, and band-bending. However a rapid, dynamic change of a field produces a potential hole that can be filled by energetic carriers, and the amount of energy released during filling process is responsible for the creation of bi-solitons. Our model based on the field-induced local hole gives excellent explanation for bi-soliton yield behaviors. Scanning tunneling spectroscopy data supports the existence of such a potential hole. The mechanism also explains the site-dependency of bi-soliton yields, which is highest at the trough, not on the dimer rows. Our study demonstrates that we can manipulate not just single atoms and molecules, but also single pseudo-spin excitations as well.

• 한국전기전자재료학회논문지
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• 제17권1호
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• pp.21-26
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• 2004

Ultra-thin silicon dioxides were grown on p-type(100) oriented silicon employing rapid thermal dry oxidation technique at the temperature range of 850∼1050 $^{\circ}C$. The growth rate of the ultra-thin film was fitted well with tile model which was proposed recently by da Silva ＆ Stosic. The capacitance-voltage, current-voltage, characteristics were used to study the electrical properties of these thin oxides. The minimum interface state density around the midgap of the MOS capacitor having oxide thickness of 111.6 $\AA$ derived from the C-V curve was ranged from 6 to 10${\times}$10$^{10}$ /$\textrm{cm}^2$eV.

• 대한전자공학회논문지
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• 제27권5호
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• pp.709-715
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• 1990

SiO2 films were nitrided by tungsten-halogen heated rapid thermal annealing in ammonia gas at temperatures of 900-1100\ulcorner for 15-180sec. The nitroxide films were analyzed using Auger electron spectroscopy. MIS caapcitors were fabricated using these films as gate insulators. I-V and C-V characteristics of MIS capacitors were investigated. The AES depth profiles of nitroxide film show that the nitrogen rich layer is, at the early stage of nitridation, formed at the surface of nitroxide film and near the interface between nitroxide and silicon. Nitridation of SiO2 makes the film have a larger effective average refractive index. The thermal nitridation of SiO2 on silicon causes the flatband voltage shift due to the change of the fixed charge density. It is found that the dominant conduction mechanism in nitroxide is Fowler-Nordheim tunneling. Rapid thermal nitridation of 200\ulcornerSiO2 on silicon results in an improvement in the dielectric breakdown electric field.

• Journal of Welding and Joining
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• 제33권2호
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• pp.14-17
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• 2015

Cleaning effect is well known mechanism of oxide layer removal in DCEP polarity. It is also known that DCEN has higher heat input efficiency than DCEP in GTAW process. Based on these two renowned arc theories, conventional variable polarity arc for aluminum welding was set up to have minimum DCEP and maximum DCEN duty ratio to achieve the highest heat input efficiency and weldability increase. However, recent several variable polarity GTA research papers reported unexpected result of proportional relationship between DCEP duty ratio and heat input. The authors also observed the same result then suggested combination of tunneling effect and random walk of cathode spot to fill up the gap between experiment and conventional arc theory. In this research, suggested combinational work of tunneling effect and rapid cathode spot changing is applied to another unexpected phenomena of variable polarity aluminum arc welding. From previous research, it is reported that wider oxide removal range, narrower bead width and shallower penetration depth are observed in thin oxide layered aluminum compared to the case of thick oxide. This result was reported for the first time and it was hard to explain the reason at that time therefore the inference by the authors was hardly acceptable. However, the suggested combinational theory successfully explains the result of the previous report in logical way.

• 한국멀티미디어학회논문지
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• 제8권2호
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• pp.258-268
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• 2005

이동 컴퓨팅 환경에서 이동 중인 호스트에게 멀티캐스트 서비스를 효율적으로 제공하는 것은 쉬운 일이 아니다. 양방향 터널링 기법은 캡슐화와 삼각 라우팅의 오버헤드를 야기하는 반면, 원격 가입 기법은 빈번한 트리 재구성을 필요로 하는데 이는 고속으로 이동하는 호스트에게는 비효율적이다. 본 논문에서는 호스트의 이동 정보에 근거하여 원격 가입 기법과 양방향 터널링 기법 사이의 장점을 찾고자 하는 이동 정보에 근거한 모바일 멀티캐스팅(MBMOM) 기법을 제안한다. 만약 호스트의 이동 속도가 고속이라고 판단되면 양방향 터널링 기법을 사용하여 홈 에이전트가 멀티 캐스트 패킷을 전달하게 된다. 만약 호스트의 이동 속도가 저속이라고 판단되면 원격 가입 기법이 적용되며 외래에이전트는 멀티 캐스트 그룹에 가입을 시도한다. 본 논문에서 제안하는 기법의 성능을 분석하기 위하여 분석 모델을 개발하였으며, MOM(Mobile Multicast)과 RBMOM (Range Based MOM), TBMOM(Timer Based MOM) 기법과 비교하여 시뮬레이션을 실시하였다. 시뮬레이션의 결과는 본 논문의 기법이 호스트의 이동 속도와 멀티캐스트 그룹의 크기 측면에서 위의 세 기법들보다 전달시간이 적게 걸리는 것을 보여주고 있다.