• 전기전자학회논문지
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• 제18권2호
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• pp.214-219
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• 2014

본 논문에서는 실리콘 카바이드(silicon carbide)를 기반으로 한 tilt-implanted trench Schottky diode(TITSD)를 제안한다. 4H-SiC 트랜치 쇼트키 다이오드(trench Schottky diode)에 형성되는 트랜치 측면에 경사 이온주입(tilt-implantation)을 하여 소자가 역저지 상태(reverse blocking mode)로 동작 시 trench insulator가 모든 퍼텐셜(potential)을 포함하는 구조를 제안하고, 그 특성을 시뮬레이션을 통해 확인하였다. TITSD는 트랜치의 측면(sidewall)에 nitrogen을 $1{\times}10^{19}cm^{-3}$ 으로 도밍(doping) 하여 항복전압(breakdown voltage) 특성도 경사 이온주입을 하지 않았을 때와 같게 유지하면서 trench oxide insulator가 모든 퍼텐셜을 포함하도록 함으로써 termination area를 감소시켰다. 트랜치 깊이(trench depth)를 $11{\mu}m$로 깊게 하고 최적화된 폭(width)을 선택함으로써 2750V의 항복전압을 얻었고, 동급의 항복전압을 가진 가드링(guard ring) 구조보다 termination area를 38.7% 줄일 수 있다. 이에 대한 전기적 특성은 synopsys사의 TCAD simulation을 사용하여 분석하였으며, 그 결과를 기존의 구조와 비교하였다.

• 한국시뮬레이션학회논문지
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• 제9권4호
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• pp.51-58
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• 2000

The control of the data retention time is a main issue for realizing future high density dynamic random access memory. The novel junction process scheme in sub-micron DRAM cell with STI(Shallow Trench Isolation) has been investigated to improve the tail component in the retention time distribution which is of great importance in DRAM characteristics. In this' paper, we propose the new implantation scheme by gate-related ion beam shadowing effect and buffer-enhanced ${\Delta}Rp$ (projected standard deviation) increase using buffered N-implantation with tilt and 4X(4 times)-rotation that is designed on the basis of the local-field-enhancement model of the tail component. We report an excellent tail improvement of the retention time distribution attributed to the reduction of electric field across the cell junction due to the redistribution of N-concentration which is Intentionally caused by ion Beam Shadowing and Buffering Effect using tilt implantation with 4X-rotation. And also, we suggest the least requirements for adoption of this new implantation scheme and the method to optimize the key parameters such as tilt angle, rotation number, Rp compensation and Nd/Na ratio. We used MEDICI Simulator to confirm the junction device characteristics. And measured the refresh time using the ADVAN Probe tester.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2000년도 추계종합학술대회 논문집(2)
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• pp.325-328
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• 2000

The control of the data retention time is a main issue for realizing future high density dynamic random access memory. In this paper, we propose the new implantation scheme by gate-related ion beam shadowing effect and buffer-enhanced $\Delta$ Rp increase using buffered N- implantation with tilt and 4X-rotation that is designed on the basis of the local-field-enhancement model of the tail component. We report an excellent tail improvement of the retention time distribution attributed to the reduction of electric field across the cell junction due to the redistribution of N- concentration which is intentionally caused by Ion Beam Shadowing and Buffering Effect using tilt implantation with 4X-rotation.

• Journal of Korean Vacuum Science & Technology
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• 제1권1호
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• pp.1-12
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• 1997

A new three-dimensional (3D) Monte Carlo ion implantation simulator, TRICSI, has been developed to investigate 3D mask effects in the typical mask structure for ion implantation into crystalline silicon. We present the mask corner and mask size effects of implanted boron range profiles, and also show the calculated damage distributions by applying the modified Kinchin-Pease equation in the single-crystal silicon target. The simulator calculates accurately and efficiently the implanted-boron range profiles under the relatively large implanted area, using a newly developed search algorithm for the collision partner in the single-crystal silicon. All of the typical implant parameters such as dose, tilt and rotation angles, in addition to energy can be used for the 3D simulation of ion implantation.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1996년도 추계학술대회 논문집
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• pp.93-96
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• 1996

We developed three dimensional Monte carlo ion implantation simulator which simulate distributions of impurities under the ion implantation on the tilted multi-layered layer. Our simulation reveals three dimensional shadow effect and sidewall scattering effect due to the geometrical shapes. For the evaluation of the developed three dimensional Monte carlo ion implantation simulator, calculations with 100,000 ions have been performed for the island and hole structures with a thin oxide of 100$\AA$ and nitride of 2000$\AA$. The simulation results showed that the distribution of ion decreases near the conner of the hole structure covered with a nitride layer and increases near the conner for the island structure open to oxide. Moreover, three dimensional distributions of ions were obtained with varying incident energy, tilt and rotation angle, mask depth and three-dimensional structure geometry.

• 한국방사선학회논문지
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• 제12권1호
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• pp.107-114
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• 2018

고관절 시행에서 식립각도는 추후 환자의 운동범위나 힘의 분배조건에 따라 폴리에틸렌 라이너의 마모에도 영향을 미친다. 인공관절요소로부터 마모입자는 골괴사나 다른 생화학적으로 많은 합병증을 일으킨다. 이런 점에서 인공고관절에서 마모와 정렬각도를 수술 후 추시를 통해 측정하는 것은 중요하다. 특히 관절면의 마모를 측정하는 것은 그 량이 크지 않아 상당한 정밀도를 요구한다. 현재 널리 쓰이는 상용 소프트웨어는 재현성과 측정방법의 표준화가 되어 있지 않아 사용에 많은 어려움이 있다. 본 논문에서는 일반 병원의 방사선촬영 환경에서 CAD만 추가로 구비하면 행할 수 있는 인공관절면 마모와 식립각 측정법을 제시한다. 인공관절만의 X-ray영상을 이용한 본 방법의 정확도와 정밀도 평가를 수행하였다. 또한 실제 인공고관절환자의 X-ray영상을 가지고 2년추시에 따른 마모와 식립각을 측정하였다. 본 연구에서 제시한 CAD를 이용한 방법은 마모측정에서 정확도 0.06 mm, 정밀도 0.05 mm, 식립각은 $0.27^{\circ}$의 정밀도를 갖는다.

• 전자공학회논문지A
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• 제32A권8호
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• pp.94-106
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• 1995

A three-dimensional(3D) Monte Carlo simulator for boron ion implantation into <100>single-crystal silicon considering the mask structure has been developed to predict the mask-dependent impurity doping profiles of the implanted boron at low energies into the reduced area according to the trend of a reduction in the size of semiconductor devices. All relevant important parameters during ion implantation have been taken into account in this simulator. These are incident energy, tilt and rotation of wafer, orientation of silicon wafer, presence of native silicon dioxide layer, dose, wafer temperature, ion beam divergence, masking thickness, and size and structure of open window in the mask. The one-dimensional(1D) results obtained by using the 3D simulator have been compared with the SIMS experiments to demonstrate its capabilities and confirem its reliability, and we obtained relatively accurate 1D doping profiles. Through these 3D simulations considering the hole structure and its size, we found the mask effects during boron ion implantation process.

• 전자공학회논문지D
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• 제35D권12호
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• pp.30-40
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• 1998

극 저 에너지 실리콘 이온 주입 시뮬레이션을 통하여 실리콘 내부에서 발생하는 격자 손상에 대하여 고전분자 동역학을 사용하여 시뮬레이션 하였다. 또한 최근에 개발된 EDIP 전위식이 실리콘 충돌 계산에 적합한지 여부를 분자 동역학을 사용하여 계산하였다. EDIP 전위식은 평형상태 계산에 알맞지만 충돌을 계산하는데는 적합하지 않았다. 또한 MDRANGE를 실리콘 공정에 맞도록 향상시켜 200eV, 500eV, 그리고 1000eV 에너지 붕소 이온 주입 시뮬레이션을 수행하여 실리콘 기판의 온도, 기울기 각도 및 에너지에 따른 붕소의 분포를 계산하였다. 1000eV 이하 에너지 붕소 이온 주입에서도 체널링 현상에 대한 고려가 필요하다는 것을 알 수 있었다.

• 한국전기전자재료학회논문지
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• 제28권11호
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• pp.683-689
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• 2015

For the formation of $N^+$ doping, the antimony ions are mainly used for the fabrication of a BJT (bipolar junction transistor), CMOS (complementary metal oxide semiconductor), FET (field effect transistor) and BiCMOS (bipolar and complementary metal oxide semiconductor) process integration. Antimony is a heavy element and has relatively a low diffusion coefficient in silicon. Therefore, antimony is preferred as a candidate of ultra shallow junction for n type doping instead of arsenic implantation. Three-dimensional (3D) profiles of antimony are also compared one another from different tilt angles and incident energies under same dimensional conditions. The diffusion effect of antimony showed ORD (oxygen retarded diffusion) after thermal oxidation process. The interfacial effect of a $SiO_2/Si$ is influenced antimony diffusion and showed segregation effects during the oxidation process. The surface sputtering effect of antimony must be considered due to its heavy mass in the case of low energy and high dose conditions. The range of antimony implanted in amorphous and crystalline silicon are compared each other and its data and profiles also showed and explained after thermal annealing under inert $N_2$ gas and dry oxidation.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2002년도 하계종합학술대회 논문집(2)
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• pp.193-196
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• 2002

This paper presents the improvement of the boron penetration and the reverse short channel effect (RSCE) in the 130nm W/WNx/Poly-Si dual gate PMOSFET for a high performance embedded DRAM. In order to suppress the boron penetration, we studied a range in the process heat budget. It has shown that the process heat budget reduction results in suppression of the boron penetration. To suppress the RSCE, we experimented with the halo (large tilt implantation of the same type of impurities as those in the device well) implant condition near the source/drain. It has shown that the low angle of the halo implant results in the suppression of the RSCE. The experiment was supported from two-dimensional(2-D) simulation, TSUPREM4 and MEDICI.