• Proceedings of the Korean Vacuum Society Conference
• /
• 2015.08a
• /
• pp.204.2-204.2
• /
• 2015

산화물 반도체는 비정질임에도 불구하고 높은 이동도를 나타내며, 적은 누설 전류, 낮은 소비전력, 저온 공정 가능, 가시광선 영역에서 투명한 성질을 가지고 있다. 이와 같은 다양한 장점들로 인해 산화물 반도체를 이용한 트랜지스터는 차세대 플랫 패널 디스플레이 적용에 있어서 핵심 기술로 각광받고 있다. 한편, 소자의 크기가 점점 더 작아짐에 따라 고집적화에 따른 scaling down은 항상 언급되는 이슈이다. 이와 관련하여 소자의 높은 on current는 트랜지스터를 더 작게 구현할 수 있다는 가능성을 보여준다. 따라서 현재 소자의 on current를 높이기 위해서 소자의 구조를 변형하는 연구가 활발히 진행되고 있다. 본 연구에서는 소자의 on current를 높이기 위한 방법으로 ITO buried layer를 이용한 산화물 반도체 pseudo 트랜지스터를 제작하였다. 먼저 채널을 형성하기 전에 ITO buried layer를 형성시켜준 후, 채널 영역으로서 InGaZnO (2:1:1)를 용액 공정을 이용하여 형성시켰다. 이어서 소자의 전기적 특성 향상을 위해 마이크로웨이브 열처리를 1800 W에서 2분간 실시하였다. 또한 대조군으로 ITO buried layer를 갖지 않는 소자를 같은 방법으로 제작하여 평가하였다. 그 결과 ITO buried later를 갖는 소자에서 대조군과 비교하여 높은 on current를 나타냄을 확인하였다. 이와 같은 결과는 낮은 저항의 ITO buried layer가 current path를 제공함과 동시에 더 두꺼운 채널 층을 형성시켜 높은 on current에 기여하기 때문이다. 결과적으로 ITO buried layer를 갖는 소자 구조를 이용함으로써 고성능 트랜지스터를 제작하여 소자를 집적화 함에 있어서 유망한 소자가 될 것으로 예상된다.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1998.05a
• /
• pp.118-118
• /
• 1998

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1997.10a
• /
• pp.109-109
• /
• 1997

• Proceedings of the Materials Research Society of Korea Conference
• /
• 1997.05a
• /
• pp.17-17
• /
• 1997

• Computers and Concrete
• /
• v.13 no.3
• /
• pp.411-421
• /
• 2014

A central pullout test was conducted to investigate the bonding properties between high strength rebar and reactive powder concrete (RPC), which covered ultimate pullout load, ultimate bonding stress, free end initial slip, free end slip at peak load, and load-slip curve characteristics. The effects of varying rebar buried length, thickness of protective layer and diameter of rebars on the bonding properties were studied, and how to determine the minimum thickness of protective layer and critical anchorage length was suggested according the test results. The results prove that: 1) Ultimate pull out load and free end initial slip load increases with increase in buried length, while ultimate bonding stress and slip corresponding to the peak load reduces. When buried length is increased from 3d to 4d(d is the diameter of rebar), after peak load, the load-slip curve descending segment declines faster, but later the load rises again exceeding the first peak load. When buried length reaches 5d, rebar pull fracture occurs. 2) As thickness of protective layer increases, the ultimate pull out load, ultimate bond stress, free end initial slip load and the slip corresponding to the peak load increase, and the descending section of the curve becomes gentle. The recommended minimum thickness of protective layer for plate type members should be the greater value between d and 10 mm, and for beams or columns the greater value between d and 15 mm. 3) Increasing the diameter of HRB500 rebars leads to a gentle slope in the descending segment of the pullout curve. 4) The bonding properties between high strength steel HRB500 and RPC is very good. The suggested buried length for test determining bonding strength between high strength rebars and RPC is 4d and a formula to calculate the critical anchorage length is established. The relationships between ultimate bonding stress and thickness of protective layer or the buried length was obtained.

• Proceedings of the IEEK Conference
• /
• 2000.11b
• /
• pp.317-320
• /
• 2000

We have calculated the optimum refractive index and thickness for a single layer antireflection coating as a function of active layer width and thickness in buried channel waveguides. The results using the variational method to obtain the field profiles are compared to those using the effective index method.

• International Journal of Highway Engineering
• /
• v.15 no.2
• /
• pp.105-112
• /
• 2013

PURPOSES : Compared to the criteria from advanced countries, Korea has conservative criteria for the buried depth of pipeline (about 30~70cm deeper) causing the waste of cost and time. Therefore, this research investigated the effect of various buried depths of pipeline on pavement performance in order to modify the criteria to be safe but economical. In addition, a recycled aggregate which is effective in economical and environmental aspect was evaluated to be used as a refilling material. METHODS : In this study, total 10 pilot sections which are composed with various combinations of pavement structure, buried depth of pipeline, and refilling material were constructed and the telecom cable was utilized as a buried pipeline. During construction, LFWD (Light Falling Weight Deflectometer) tests were conducted on each layer to measure the structural capacity of underlying layers. After the construction is completed, FWD (Falling Weight Deflectometer) tests and moving load tests were performed on top of the asphalt pavement surface. RESULTS : It was found from the LFWD and FWD test results that as the buried depth decrease, the deflections in subbase and surface layer were increased by 30% and 5~10%, respectively, but the deflection in base layer remained the same. In the moving load test, the longitudinal maximum strain was increased by 30% for 120mm of buried depth case and 5% for 100mm of buried depth case. Regarding the effect of refilling material, it was observed that the deflections in subbase and surface layer were 10% lager in recycled aggregate compared to the sand material. CONCLUSIONS : Based on the testing results, it was found that the change in buried depth and refiliing material would not significantly affect the pavement performance. However, it is noted that the final conclusion should be made based on an intensive structural analysis for the pavement under realistic conditions (i.e., repeated loading and environmental loading) along with the field test results.

• Journal of IKEEE
• /
• v.2 no.1 s.2
• /
• pp.101-107
• /
• 1998

This paper is studied micro-defect characteristics by phosphorus 1MeV ion implantation and Rs, SRP, SIMS, XTEM for the RTA process was measured and simulated. As the dose is higher, the Rs is lower. When the dose are $1{\times}10^{13}/cm^2,\;5{\times}10^{13}/cm^2,\;1{\times}10^{14}/cm^2$, the Rp are $1.15{\mu}m,\;1.15{\mu},\;1.10{\mu}m$ respectively. As the RTA time is longer, the maximum concentration position is deeper from the surface and the concentration is lower. Before the RTA was done, we didn't observe any defect. But after the RTA process was done, we could observe the RTA process changed the micro-defects into the secondary defects. The simulation using the buried layer and connecting layer structure was performed. As results, the connecting layer had more effect than the buried layer to latch-up immune. Trigger current was more $0.6mA/{\mu}m$ and trigger voltage was 6V at dose $1{\times}10^{14}/cm^2$ and the energy 500KeV of connecting layer Lower connecting layer dose, latch-up immune characteristics was better.

• The Transactions of the Korean Institute of Electrical Engineers C
• /
• v.55 no.3
• /
• pp.111-115
• /
• 2006

We investigated accelerated soft error rate(ASER) in 8M static random access memory(SRAM) cells. The effects on ASER by well structure, operational voltage, and cell transistor threshold voltage are examined. The ASER decreased exponentially with respect to operational voltage. The chips with buried nwell1 layer showed lower ASER than those either with normal well structure or with buried nwell1 + buried pwell structure. The ASER decreased as the ion implantation energy onto buried nwell1 changed from 1.5 MeV to 1.0 MeV. The lower viscosity of the capping layer also revealed lower ASER value. The decrease in the threshold voltage of driver or load transistor in SRAM cells caused the increase in the transistor on-current, resulting in lower ASER value. We confirmed that in order to obtain low ASER SRAM cells, it is necessary to also the buried nwell1 structure scheme and to fabricate the cell transistors with low threshold voltage and high on-current.

• Proceedings of the KIEE Conference
• /
• 2006.07b
• /
• pp.777-778
• /
• 2006

This paper deals with the optimum rotor design approach about the multi-layer design of the buried magnets in an Interior Permanent Magnet Synchronous Motor (IPMSM), on the efficiency improvement by using Response Surface Methodology (RSM). In the multi-layer design of the prototype 15kw IPMSM, the constant amount of buried PM is split from the single-layer into double-layer design for improving the efficiency characteristics. The optimum double-layer rotor structure is built with the help of RSM analysis. The improvement of IPMSM efficiency is verified by the Finite Element Method (FEM) results comparison with the prototype single-layer IPMSM.