• Proceedings of the Materials Research Society of Korea Conference
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• 2003.03a
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• pp.118-118
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• 2003

전력반도체 소자로 사용되는 p$^{-}$-n$^{-}$ 접합 다이오드의 스위칭 속도를 향상시키고 그에 따른 에너지 손실을 감소시키기 위해 전자 조사를 실시하였다. Reverse recovery time이 현저히 감소한 반면, 전자 조사에 의한 누설전류와 on-state 전압 강하와 같은 그 외의 전기적 특성 저하는 무시할 수 있는 정도였다. 그밖에 시료의 deep level transient spectroscpy(DLTS) 분석 결과와 secondary ion mass spectrometry(SIMS) depth profile을 근거로 결함 분포와 전자조사 유도결함의 유형을 논하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.866-869
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• 2001

In this study, (Ba,Sr)TiO$_3$(BST) thin films were etched with a magnetically enhanced inductively coupled plasma(MEICP). Etching characteristics of BST thin films including etch rate and selectivity were evaluated as a function of the etching parameters such as gas mixing ratio, rf power, dc bias voltage and chamber pressure. The maximum etch rate of the BST films was 1700 $\AA$/min at Ar(90)/CF$_4$(10), 600 W/350 V and 5 mTorr. The selectivity of BST to PR was 0.6, 0.7, respectively. To analyze the composition of surface residue remaining after the etching, samples etched with different CF$_4$/Ar gas mixing ratio were investigated with X-ray photoelectron spectroscopy (XPS) and secondary ion mass spectrometry (SIMS). From the results of XPS and SIMS, there are chemical reaction between Ba, Sr, Ti and C, F radicals during the etching and remained on the surface.

• Macromolecular Research
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• v.14 no.2
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• pp.205-208
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• 2006

A polymeric film of a biodegradable poly(1,5-dioxepan-2-one) (PDXO) was formed on a gold surface by a combination of the formation of self-assembled monolayers (SAMs) presenting hydroxyl groups and the surface-initiated, ring-opening polymerization (SI-ROP) of 1,5-dioxepan-2-one (DXO). The SI-ROP of DXO was achieved by heating a mixture of $Sn(Oct)_2$, DXO, and the SAM-coated substrate in anhydrous toluene at $55^{\circ}C$. The resulting PDXO film was quite uniform. The PDXO film was characterized by polarized infrared external reflectance spectroscopy, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry, atomic force microscopy, ellipsometry, and contact angle goniometry.

• Journal of the Korean Solar Energy Society
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• v.34 no.4
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• pp.39-44
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• 2014

The elemental composition of electro-deposited black Cr solar selective coatings before and after heating in air by using secondary ion mass spectrometry (SIMS) was investigated for optical property analysis. In addition, black Cr selective coating exposed by solar radiation for 5 months was compared with heated sample. SIMS investigation shows that $OH^+$ bearing ions were related to a near surface region of CrOH and CrO compound. The optical degradation of this coating after heating at $500^{\circ}C$ reveals that diffusion of the Cu and Ni elements in substrate material, the chemical interactions adjacent to the interface, and the interface width broadening.

• ETRI Journal
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• v.11 no.4
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• pp.75-83
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• 1989

The diffusion mechanism of Si in GaAs was investigated using different diffusion sources based on the Si-Ga-As ternary phase equilibria. The Si profiles are measured with secondary ion mass spectrometry and differ significantly for sources taken from the different phase fields in the ternary phase diagram. Neutral As vacancy diffusion is proposed for acceptor Si diffusion anneals using a Ga - Si - GaAs source. Donor Si diffusion using As - rich sources and a Si -GaAs tie line source shows concentration dependent diffusion behavior. Concentration dependent diffusion coefficients of donor Si for As - rich source diffusion were found to be related to net ionized donor concentration and showed three regimes of different behavior: saturation regime, intermediate regime,and intrinsic regime. Ga vacancies are proposed to be responsible for donor Si diffusionin GaAs: $Si_Ga^+V_Ga^-$ (donor Si -acceptor Gavacancy) complex for the extrinsic regime and neutral $V_G$a, for the intrinsic regime.The Si - GaAs tie line source resulted in two branch profiles, intermediate between the As - rich and the Ga - rich source diffusion cases.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.26 no.5
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• pp.373-379
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• 2013

Mg-doped zinc tin oxide (ZTO:Mg) thin films were prepared on glasses by rf magnetron sputtering. $O_2$ was introduced into the chamber during the sputtering. The optical properties of the films as a function of oxygen flow rate were studied. The crystal structure, elementary properties, and depth profiles of the films were investigated by X-ray diffraction (XRD), x-ray photoelectron spectroscopy (XPS), and secondary ion mass spectrometry (SIMS), respectively. Bottom-gate transparent thin film transistors were fabricated on $N^+$ Si wafers, and the variation of mobility, threshold voltage etc. with the oxygen flow rate were observed.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.212-212
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• 2014

이트리아 안정화 지그코니아(Yttria-stabilized zirconia, YSZ)는 이트리아의 첨가에 의해 지르코니아에 생성된 산소 빈자리(oxygen vacancy)로 $O^{2-}$ 이온이 전도성을 가지게 되는 특징이 알려지면서 최근 고체산화물 연료전지연구에서 많은 관심을 받고 있다.[1] YSZ를 기반으로한 고체산화물 연료전지의 특성을 개선하기 위해서는 YSZ 내에서의 산소교환 메카니즘을 이해하는 것이 매우 중요하다. 본 연구에서는 $^{18}O2$ 추적 기체(tracer gas) 이용하여 확산된 YSZ박막에서의 산소 확산 거동을 초미세이차이온질량분석기(Nano Secondary Ion Mass Spectrometry, Nano SIMS)를 이용하여 조사하였다. Nano SIMS는 작은 입사 이온빔의 크기를 구현할 수 있고, 다중검출기를 이용하여 높은 질량분해능으로 간섭없이 산소동위원소를 동시에 모두 검출할 수 있는 장점이 있다. 본 발표에서는 Nano SIMS를 이용한 YSZ박막에서의 산소 거동 평가 결과를 상세하게 보일 것이다.

• Proceedings of the Mineralogical Society of Korea Conference
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• 2005.05a
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• pp.50-57
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• 2005

Although the bulk composition of materials is one of the major considerations in extractive metallurgy and environmental science, surface composition and topography (edges and dislocations are preferred sites for physicochemical reactions) control surface reactivity, and consequently play a major role in determining metallurgical phenomena and pollution by heavy metals and organics. An understanding of interaction mechanisms of different chemical species with the mineral surface in an aqueous media is very important in natural environment and metallurgical processing. X-ray photoelectron spectroscopy (XPS) has been used as an ex-situ analytical technique, but the material to be analyzed can be any size from $100{\mu}m$ up to about 1 cm. It can also measure mixed solids powders, but it is impossible to ascertain the original source of resulting x-ray signals where they were emitted from, since it radiates and scans the macro sample surface area.

• Journal of Sensor Science and Technology
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• v.24 no.1
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• pp.35-40
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• 2015

Electrospinning method has easy preparation of nanofibers with a simple and versatile technique. Electrospun nanofiber is widely used by the simple approach and have great potentials in the numerous applicaitons of medicine, photonics, catalysts, sensors, etc. including advantage of their specific characteristics such as large surface to volume ratio. This paper focused on the fabrication of cobalt electrospun nanofibrer for applications such as electronic, optical and mechanical devices by metal based material. We fabricated cobalt nanofibers on aluminum foil by an electrospinning method. The electrospinning process was performed at a high voltage, 8 kV. The distance between the needle tip and the solution surface in the bath was 5 cm. The PVB - cobalt based nitrate solution was filled in a 10 mL syringe connected to a 22 gauge needle. We confirmed electrospun cobalt nanofiber after annealing process by SIMS (Secondary Ion Mass Spectrometry) analysis. The concept design, fabrication and results of mapping measurements are reported.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.367-367
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• 2011

CIGS solar cell with copper, indium, gallium and selenium is a second generation solar cells for the lowering of the manufacturing cost. The relative ratio of the four elements is one of the most important measurement issues because the photovoltaic property of CIGS solar cell depends on the crystalline structure of the CIGS layer. However, there is no useful analysis method for the composition of the CIGS layer. Recently, AES depth profiling analysis of CIGS films has been studied with a reference material certified by inductively coupled plasma optical emission spectroscopy. However, there are some problems in AES depth profiling analysis of CIGS films. In this study, the in-depth profiling analysis was investigated by secondary ion mass spectrometry (SIMS) depth profiling analysis. We will present the compositional depth profiling of CIGS films by SIMS and its applications for the development of CIGS solar cells with high efficiency.