• 한국재료학회지
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• 제18권6호
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• pp.302-306
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• 2008

Polycrystalline germanium (Ge) thin films were grown by metal organic chemical vapor deposition (MOCVD) using tetra-allyl germanium [$Ge(allyl)_4$], and germane ($GeH_4$) as precursors. Ge thin films were grown on a $TiN(50nm)/SiO_2/Si$ substrate by varying the growth conditions of the reactive gas ($H_2$), temperature ($300-700^{\circ}C$) and pressure (1-760Torr). $H_2$ gas helps to remove carbon from Ge film for a $Ge(allyl)_4$ precursor but not for a $GeH_4$ precursor. $Ge(allyl)_4$ exhibits island growth (VW mode) characteristics under conditions of 760Torr at $400-700^{\circ}C$, whereas $GeH_4$ shows a layer growth pattern (FM mode) under conditions of 5Torr at $400-700^{\circ}C$. The activation energies of the two precursors under optimized deposition conditions were 13.4 KJ/mol and 31.0 KJ/mol, respectively.

• 한국세라믹학회지
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• 제18권1호
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• pp.23-26
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• 1981

The electrical conductivity of highly pure polycrystalline $Yb_2O_3$ has been measured from 650 to 105$0^{\circ}C$ under oxygen pressure range of $10^{-5}$ to 102 torr. The conductivity dependence of oxygen pressure in the temperature region from 750 to 105$0^{\circ}C$ is approximated by $\sigma$ $\alpha$ $Po_2^{1/5.3}$. This shows that the conduction mechanism is associated with doubly ionized metal vacancies. Fairly low activation energy and the lack of oxygen pressure dependence are found over the temperature range of 650 to 75$0^{\circ}C$. The conduction mechanism can be explaned by not metal vacancies, but hopping oxygen ions in the oxide.

• 마이크로전자및패키징학회지
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• 제12권2호
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• pp.135-140
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• 2005

Although it was recently observed that severe fatigue damage was formed in Al or Cu interconnects due to the cyclic temperatures generated by Joule heating of the metal lines by the passage of alternating currents (AC), AC loading frequency effect on the damage evolution characteristics are not known so far. This work focused on the effect of AC loading frequency (100 Hz vs. 10 kHz) on the thermo-mechanical fatigue characteristics by using polycrystalline sputtered Cu lines with temperature cycles with amplitudes from 100 to $300^{\circ}C$. It was consistently observed that higher loading frequency accelerated damaged grain growth and led to earlier failure irrespective of Cu grain sizes. The frequency effect is believed to result from differences in the concentration of defects created by the deformation-induced motion of dislocations to the grain boundaries.

• Journal of Magnetics
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• 제20권2호
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• pp.138-147
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• 2015

The unique nano-scale inter-lamellar microstructure and unparalleled heat treatment process give our developed metal powder composite its outstanding magnetic property for power inductor & motor applications. Compared to the conventional polycrystalline Fe or amorphous Fe-Cr-Si-B alloys, our unique designed inter-lamellar microstructure strongly decreases the intra-particle eddy current loss at high frequencies by blocking the mutual eddy currents. The combination of optimum permeability, magnetic flux and extremely low core loss makes this powder composite suitable for high frequency applications well above 10 MHz. Moreover, it can be also possible to SMC core for high speed motor applications in order to increase the motor efficiency by decreasing the core loss.

• 융합정보논문지
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• 제9권5호
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• pp.117-124
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• 2019

본 논문에서는 AMOLED 디스플레이 구동회로로 사용되는 박막트랜지스터의 구성요소 중에서 반도제 물질 제조의 최근 동향에 대해 논한다. 트랜지스터에 적용을 위해 특성이 좋은 반도체 막을 얻는 방법으로 비정질 실리콘을 다결정 실리콘으로 변화시켜야 하는데 레이저와 열처리 방법이 있으며, 레이저를 이용한 기술에는 SLS(Sequential Lateral Solidification), ELA(Excimer Laser Annealing), TDX(Thin-beam Directional Crystallization), 열처리 기술에는 SPC(Solid Phase Crystallization), SGS(Super Grain Silicon), MIC(Metal Induced Crystallization), FALC(Field Aided Lateral Crystallization)가 대표적이며, 이들에 대해 상세히 설명한다. 본 연구실에서 연구중인 레이저 결정화 기술의 대형 AMOLED 디스플레이 제작을 위한 연구 내용도 다룬다.

• 한국세라믹학회지
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• 제44권8호
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• pp.403-406
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• 2007

Ferroelectric Ce-doped $Bi_4Ti_3O_{12}$ (BCT) thin films were deposited by liquid delivery metal organic chemical vapor deposition (MOCVD) onto a $Pt(111)/Ti/SiO_2/Si(100)$ substrate. X-ray diffraction (XRD) and scanning electron microscopy (SEM) were used to identify the crystal structure, the surface, and the cross-section morphology of the deposited ferroelectric flims. After annealing above $640^{\circ}C$, the BCT films exhibited a polycrystalline structure with preferred (001) and (117) orientations. The BCT lam capacitor with a top Pt electrode showed a large remnant polarization ($2P_r$) of $44.56{\mu}C/cm^2$ at an applied voltage of 5 V and exhibited fatigue-free behavior up to $1.0{\times}10^{11}$ switching cycles at a frequency of 1 MHz. This study clearly reveals that BCT thin film has potential for application in non-volatile ferroelectric random access memories and dynamic random access memories.

• JSTS:Journal of Semiconductor Technology and Science
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• 제16권6호
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• pp.854-859
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• 2016

Recently, GeSn is drawing great deal of interests as one of the candidates for group-IV-driven optical interconnect for integration with the Si complementary metal-oxide-semiconductor (CMOS) owing to its pseudo-direct band structure and high electron and hole mobilities. However, the large lattice mismatch between GeSn and Si as well as the Sn segregation have been considered to be issues in preparing GeSn on Si. In this work, we deposit the GeSn films on Si by DC magnetron sputtering at a low temperature of $250^{\circ}C$ and characterize the thin films. To reduce the stresses by GeSn onto Si, Ge buffer deposited under different processing conditions were inserted between Si and GeSn. As the result, polycrystalline GeSn domains with Sn atomic fraction of 6.51% on Si were successfully obtained and it has been demonstrated that the Ge buffer layer deposited at a higher sputtering power can relax the stress induced by the large lattice mismatch between Si substrate and GeSn thin films.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.1
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• pp.155-159
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• 2003

Polycrystalline $Ti_{1-x}Co_xO_2$ thin films on $SiO_2$ (200 nm)/Si (100) substrates were prepared using liquid-delivery metalorganic chemical vapor deposition. Microstructures and ferromagnetic properties were investigated as a function of doped Co concentration. Ferromagnetic behaviors of polycrystalline films were observed at room temperature, and the magnetic and structural properties strongly depended on the Co distribution, which varied widely with doped Co concentration. The annealed $Ti_{1-x}Co_xO_2$ thin films with $x{\leq}0.05$ showed a homogeneous structure without any clusters, and pure ferromagnetic properties of thin films are only attributed to the $Ti_{1-x}Co_xO_2$ (TCO) phases. On the other hand, in case of thin films above x=0.05, Co clusters formed in a homogeneous $Ti_{1-x}Co_xO_2$ Phase, and the overall ferromagnetic (FM) properties depended on both $FM_{TCO}$ and $FM_{Co}$. Co clusters with about 10nm-150nm size decreased the value of Mr (the remanent magnetization) and increased the saturation magnetic field.

• 한국전기전자재료학회논문지
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• 제37권1호
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• pp.26-35
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• 2024

Aluminum-induced crystallization (AIC) as a route to reduce the fabrication cost and to obtain polycrystalline Si (p-Si) thin-film of large grain size is a promising alternative of single-crystalline (s-Si) substrate or p-Si thin-film obtained by conventional methods such as solid phase crystallization (SPC) and laser-induced crystallization (LIC). As the AIC process occurs at the interface between a-Si and Al thin-films, there are various process and interface parameters. Also, it directly means that there is a certain parametric window to obtain p-Si of large grain size having uniform crystal orientation. In this article, we investigate the effect of the various process and interface parameters to obtain p-Si of large grain size and uniform crystal orientation from the literature review. We also suggest the potential use of the p-Si as a virtual substrate for the growth of various compound semiconductors in a form of low-dimension as well as thin-film as a way for their monolithic integration on Si.

• 한국조명전기설비학회:학술대회논문집
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• 한국조명전기설비학회 2008년도 추계학술대회 논문집
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• pp.81-84
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• 2008

1960년대 중반부터 이미 고압 나트륨램프에 사용되어 오던 반투명의 세라믹 재료(Polycrystalline Ceramic Alumina ; PCA)를 기존 메탈핼라이드램프의 석영(Quartz) 발광관에 적용시킨 세라믹 메탈핼라이드(Ceramic Metal Halide ; CMH) 램프는 1995년 처음 소개된 이래 색 제어, 연색성, 광속유지율 등에서 전통적인 석영 메탈핼라이드(Quartz Metal Halide ; QMH)램프보다 우수한 특성을 가지고 있어 저와트급(150W이하)에서 고와트급에 이르기까지 폭넓게 사용되어지고 있으며 현재 국내에서도 이러한 CMH램프의 개발이 진행 중이다. 본 논문에서는 CMH램프의 우수한 특성을 살펴보기 위하여 국외 선진제품에 대한 전기적, 광학적 특성을 살펴보았으며 실험 결과 CMH 램프의 광속유지 율이 기존 QMH 램프보다 우수한 특성을 갖는 것을 확인할 수 있었다.