• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.243-243
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• 2010

$CN_x$ films fabricated by different deposition techniques to synthesize of $\beta-C_3N_4$ involve two problems; nitrogen deficiency and $sp^2$ hybridized bonding. Nitrogen contents in most of the thin films are lower than stoichiometric composition 57%

• 한국세라믹학회지
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• 제20권4호
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• pp.305-314
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• 1983

In order to enhance the rate of th nitridation and to give the high density of reaction-bonded silicon nitride MgO powder as nitriding aid were added to silicon powders and the mixture was pressed isostatically into compacts which were nitrided in the furnace of 1, 35$0^{\circ}C$ where 95% $N_2$-5% $H_2$ gases were flowing. As the other nitriding aid $Mg(NO_3)_2 6H_2O$ was selected, A slip made of magnesium nitrate solution and fine silicon particles was spray-dried and then decomposed at 30$0^{\circ}C$. Magnesium oxide-coated silicon powders were formed into compacts prior to the nitridation on the same condition as the former. Magnesium nitrate (MgO, produced from the decomposition of magnesium nitrate) was more effective for the formation of the $\beta$-phase in the initial stage of the nitridation probably due to the easy formation of $MgO-SiO_2$-metal oxide eutectic melt. It has been confirmed that forsterite was formed as a result of the reaction between MgO and $SiO_2$ film of silicon surface. It was considered that MgO produced from magnesium nitrate may be finer more reactive and more uniformly distributed on the surface of silicon particles than original MgO. The higher the forming pressure was the more the $\beta$-phase was formed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1991년도 추계학술대회 논문집 학회본부
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• pp.241-244
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• 1991

In this paper, we introduced Silicon Oxynitride films deposited by Laser CVD, and evaluated the electrical breakdown of these films by TZDB(Time Zero Dielectric Breakdown) and TDDB(Time Dependent Dielectric Breakdown) test. In addition, high frequency C-V test was done in order to calculate hysterisis and flatband voltage(before and after electric field stress). Failure times against eletric field are examined and electric field accelation factor $\beta$ are obtained, and long term reliability was also described by extrapolating into life time in the operating voltage(5V). In this experiments, the deposited films with increased temperature represented small flatband voltage, hysterisis and favorable breakdown characteristics, this is why the hydrogen in the film was decreased and the film was densified, long term reliability was good in the laser CVD SiON films.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2017년도 춘계학술대회 논문집
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• pp.152-152
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• 2017

Titanium and its alloys have been widely used for biomedical applications. However, the use of the Ti-6Al-4V alloy in biomaterial is then a subject of controversy because aluminum ions and vanadium oxide have potential detrimental influence on the human body due to vanadium and aluminum. Hence, recent works showed that the synthesis of new Ti-based alloys for implant application involves more biocompatible metallic alloying element,such as, Nb, Hf, Zr and Mo. In particular, Nb and Hf are one of the most effective Ti ${\beta}$-stabilizer and reducing the elastic modulus. Plasma electrolyte oxidation (PEO) is known as excellent method in the biocompatibility of biomaterial due to quickly coating time and controlled coating condition. The anodized oxide layer and diameter modulation of Ti alloys can be obtained function of improvement of cell adhesion. Silicon (Si) and magnesium (Mg) has a beneficial effect on bone. Si in particular has been found to be essential for normal bone and cartilage growth and development. In vitro studies have shown that Mg plays very important roles in essential for normal growth and metabolism of skeletal tissue in vertebrates and can be detected as minor constituents in teeth and bone. Therefore, in this study, Si and Mg coatings on the hydroxyapatite film formed Ti-29Nb-xHf alloys by plasma electrolyte oxidation has been investigated using several experimental techniques. Ti-29Nb-xHf (x= 0, 3, 7 and 15wt%, mass fraction) alloys were prepared Ti-29Nb-xHf alloys of containing Hf up from 0 wt% to 15 wt% were melted by using a vacuum furnace. Ti-29Nb-xHf alloys were homogenized for 2 hr at $1050^{\circ}C$. The electrolyte was Si and Mg ions containing calcium acetate monohydrate + calcium glycerophosphate at room temperature. The microstructure, phase and composition of Si and Mg coated oxide surface of Ti-29Nb-xHf alloys were examined by FE-SEM, EDS, and XRD.

• 대한치과보철학회지
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• 제43권5호
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• pp.684-693
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• 2005

Statement of problem: Ti-6Al-7Nb alloy is used instead of Ti-6Al-4V alloy that was known to have toxicity. Purpose: This study was performed to investigate the effect of electrolyte concentration on the surface characteristics of anodized and hydrothermally-treated Ti-6Al-7Nb alloy Materials and methods: Discs of Ti-6Al-7Nb alloy of 20 mm in diameter and 2 mm in thickness were polished sequentially from #300 to 1,000 SiC paper ultrasonically washed with acetone and distilled water for 5 min, and dried in an oven at $50^{\circ}C$ for 24 hours. Anodizing was performed at current density $30mA/cm^2$ up to 300 V in electrolyte solutions containing $\beta-glycerophosphate$ disodium salt hydrate $(\beta-GP)$ and calcium acetate (CA). Hydrothermal treatment was conducted by high pressure steam at $300^{\circ}C$ for 2 hours using a autoclave. All samples were soaked in the Hanks' solution with pH 7.4 at $36.5^{\circ}C$ for 30 days. Results and conclusion: The results obtained were summarized as follows: 1. After hydrothermal treatment, the precipitated HA crystals showed the dense fine needle shape. However, with increasing the concentration of electrolyte they showed the shape of thick and short rod. 2. When the dense fine needle shape crystals was appeared after hydrothermal treatment, the precipitation of HA crystals in Hanks' solution was highly accelerated. 3. The crystal structures of $TiO_2$ in anodic oxide film were composed of strong anatase peak and weak rutile peak as analyzed with thin-film X-ray diffractometery. 4. The Ca/P ratio of the precipitated HA layer was equivalent to that of HA crystal in Hanks' solution.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 하계학술대회 논문집 Vol.7
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• pp.169-170
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• 2006

In this study, ultra thin films of ferroelectric vinylidene fluoride-trifluoroethylene (VF2-TrFE) copolymer were fabricated on degenerated Si (n+, $0.002\;{\Omega}{\cdot}cm$) using by spin coating method. A 1~5 wt% diluted solution of purified vinylidene fluoride-trifluoroethylene (VF2:TrFE=70:30) in a dimethylformamide (DMF) solvent were prepared and deposited on silicon wafers at a spin rate of 2000~5000rpm for 30 seconds. After annealing in a vacuum ambient at $200^{\circ}C$ for 60 min, upper gold electrodes were deposited by vacuum evaporation for electrical measurement. X-ray diffraction results showed that the VF2-TrFE films on Si substrates had $\beta$-phase of copolymer structures. The capacitance on $n^+$-Si(100) wafer showed hysteresis behavior like a butterfly shape and this result indicates clearly that the dielectric films have ferroelectric properties. The typical measured remnant polarization (2Pr) and coercive filed (EC) values measured using a computer controlled a RT-66A standardized ferroelectric test system (Radiant Technologies) were about $0.54\;C/cm^2$ and 172 kV/cm, respectively, in an applied electric field of ${\pm}0.75\;MV/cm$.

• 한국재료학회:학술대회논문집
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• 한국재료학회 1999년도 추계학술발표강연 및 논문개요집
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• pp.76-76
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• 1999

Low resistance ohmic contacts to the Si-doped InGaN(~$\times$10$^{19}$ ㎤) were obtained using the W metallization schemes. Specific contact resistance decreased with increasing annealing temperature. The lowest resistance is obtained after a nitrogen ambient annealing at 95$0^{\circ}C$ for 90s, which results in a specific contact resistance of 2.75$\times$10$^{-8}$ Ω$\textrm{cm}^2$. Interfacial reactions and surface are analyzed using x-ray diffraction, transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The X-ray diffraction results show that the reactions between the W film and the InGaN produce a $\beta$-W$_2$N phase at the interface. TEM results also show that the $\beta$-W$_2$N has a rough interface, which increase contact area. It shows that the morphology of the contacts is stable up to a temperature as high as 95$0^{\circ}C$. Possible mechanisms are proposed to describe the annealing temperature dependence of the specific contact resistance.

• 한국전기전자재료학회논문지
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• 제16권12호
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• pp.1103-1109
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• 2003

Crystalline carbon nitride films have been deposited by RF reactive magnetron sputtering system with negative DC bias. The carbon nitride films deposited on various substrates showed ${\alpha}$- C$_3$N$_4$,${\beta}$-C$_3$N$_4$ and lonsdaleite structures through XRD and FTIR We can find the grain growth of hexagonal structure from SEMI photographs, which is coincident with the theoretical carbon nitride unit cell. When nitrogen gas ratio is 70 % and RF power is 200 W, the growth rate of carbon nitride film on quartz substrate is about 2.1 $\mu\textrm{m}$/hr.

• 한국진공학회지
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• 제17권6호
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• pp.518-522
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• 2008

반도체 집적도의 비약적인 발전으로 박막은 더욱 다층화 되고 선폭은 더욱 미세화가 진행되었다. 이러한 악조건에서 소자의 집적도를 계속 향상시키기 위하여 많은 연구가 진행되고 있다. 특히 소자 집적도 향상으로 금속 배선 공정에서는 선폭의 미세화와 배선 길이 증가로 인한 RC지연이 발생하게 되었다. 이를 방지하기 위하여 Al보다 비저항이 작은 Cu를 배선물질로 사용하여야 하며, 또한 일부 공정에서는 이미 사용하고 있다. 그러나 Cu를 금속배선으로 사용하기 위해 해결해야 할 가장 큰 문제점은 저온에서 쉽게 Si기판과 반응하는 문제이다. 현재까지 본 실험실에서는 tungsten (W)을 주 물질로 W-C-N (tungsten- carbon - nitrogen) 확산방지막을 증착하여 연구를 하였으며, $\beta$-ray, XRD, XPS 분석을 통하여 고온에서도 Cu의 확산을 효과적으로 방지한다는 연구 결과를 얻었다. 이 연구에서는 기존 연구에 추가적으로 W-C-N 확산방지막의 표면을 Nano-Indenter System을 이용하여 확산방지막 표면강도 변화를 분석하여 확산방지막의 물성 특성을 연구하였다. 이러한 연구를 통하여 박막내 불순물인 질소가 포함된 박막이 고온 열처리 과정에서 보다 안정적인 표면강도 변화를 나타내는 연구 결과를 얻었으며, 이로부터 박막의 물성 분석을 실시하였다.

• 한국결정성장학회지
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• 제34권1호
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• pp.1-7
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• 2024

β-Ga₂O₃는 ~4.8 eV의 넓은 밴드 갭과 8 MV/cm의 높은 항복 전압을 가지는 물질로 전력소자의 응용 분야에서 많은 주목을 받고 있다. 또한, 대표적인 WBG 반도체 소재인 SiC, GaN, 다이아몬드 등과 비교했을 때, 높은 성장률과 낮은 제조 비용으로 단결정 성장이 가능하다는 장점을 가진다[1-4]. 본 연구에서는 다중 슬릿 구조를 이용한 EFG(Edge-defined Film-fed Growth) 법을 통해 SnO₂ 0.3 mol% 도핑된 10 mm 두께의 β-Ga₂O₃ 단결정을 성장시키는 데에 성공했다. 성장 방향과 성장 면은 각각 [010]/(001)로 설정하였으며 성장 속도는 약 12 mm/h이다. 성장시킨 β-Ga₂O₃ 단결정은 다양한 결정면(010, 001, 100, ${\bar{2}}01$)으로 절단하여 표면 가공을 진행하였다. 가공이 완료된 샘플은 XRD, UV/VIS/NIR Spec., Mercury Probe, AFM, Etching 등의 분석을 통해 결정면에 따른 특성을 비교하였다. 본 연구는 고전압 및 고온 응용 분야에서 전력반도체 기술의 발전에 기여할 것으로 기대되며 더 나은 특성의 기판을 선택하는 것은 소자의 성능과 신뢰성을 향상시키는데에 중요한 역할을 할 것이다.