Co-electrodeposition of U and Mo from a LiCl-KCl melt

Lee, Na-Ri,Kang, Byungman,Choi, Suhee,Bae, Sang-Eun,Park, Tae-Hong,Kim, Jong-Yun,Kim, Jongwon ELSEVIER 2018 JOURNAL OF NUCLEAR MATERIALS Vol.499 No.-

<P><B>Abstract</B></P> <P>Co-electrodeposition of uranium and molybdenum from a LiCl-KCl melt was investigated using cyclic voltammetry (CV), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The electrochemical study showed that the electrodeposition of Mo occurred from a molten LiCl-KCl eutectic at potentials more negative than −0.3 V vs. Ag|Ag<SUP>+</SUP>. Electrodeposition at a low overpotential range (between −0.3 V and −0.35 V) resulted in flat, thin Mo films, whereas greater overpotentials led to the growth of 3D films. Conditions for simultaneous electrodeposition of U and Mo were then optimized by varying the concentrations of UCl<SUB>3</SUB> and MoCl<SUB>3</SUB> and the electrodeposition method applied. At a constant potential of −1.58 V, a melt containing 1.3 wt% UCl<SUB>3</SUB> and 1.5 wt% MoCl<SUB>3</SUB> resulted in the co-electrodeposition of dendrites due to the high overpotential for Mo electrodeposition. However, diffusion-controlled electrodeposition using the same potential and concentration resulted in a uniform and flat U-Mo film. This co-electrodeposition of U-Mo films could be applied to the preparation of low-cost U-Mo nuclear fuel.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Co-electrodeposition of U and Mo from a LiCl-KCl melt was investigated. </LI> <LI> First individual deposition of U and Mo was studied, followed by co-deposition. </LI> <LI> Using a constant potential resulted in dendrite formation from the melt. </LI> <LI> Diffusion-controlled deposition resulted in a flat, uniform U-Mo film. </LI> </UL> </P>

Selective copper metallization of nonconductive materials using jet-circulating electrodeposition

Kim, Haan,Kim, Jang Gil,Park, Jong Wuk,Chu, Chong Nam Elsevier 2018 Precision engineering Vol.51 No.-

<P><B>Abstract</B></P> <P>In this paper, a novel selective copper metallization technique that can be used on various materials, such as glass, plastic and ceramic, is proposed. The process consists of three steps: seed layer development, pattern fabrication using jet-circulating electrodeposition, and seed layer removal. A copper seed layer for electrodeposition was formed on various materials by electron beam evaporation. Jet-circulating electrodeposition was implemented to fabricate micro-metal patterns. Localizing the circulation of a jetted electrolyte through two concentric nozzles enables rapid selective electrodeposition. The geometry of the copper pattern was investigated by means of scanning electron microscopy (SEM) and a surface profiler. As a result, copper pattern in various shapes was fabricated. The usage of an outer diameter of 290μm electrode nozzle, results in a copper pattern with a width of 430μm and a height of 28μm. Parameter study of the jet-circulating electrodeposition condition to investigate the electrodeposition mode, electrolyte jetting pressure, and average current was performed to control the width, height and surface roughness of the deposited pattern.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Copper pattern metallization using jet-circulating electrodeposition is proposed. </LI> <LI> Selective metal patterning can be achieved via jet-circulating electrodeposition process. </LI> <LI> Pulse-reverse electrodeposition technique should be applied for high deposition rate. </LI> <LI> Electrolyte jetting condition should be controlled during deposition process. </LI> </UL> </P>

Cu direct electrodeposition using step current for superfilling on Ru-Al₂O₃ layer

Kim, M.J.,Choe, S.,Kim, H.C.,Lee, S.J.,Kim, S.H.,Kwon, O.J.,Kim, J.J. Pergamon Press 2014 ELECTROCHIMICA ACTA Vol.147 No.-

A Ru-Al<SUB>2</SUB>O<SUB>3</SUB> layer can be used as an integrated material in a diffusion barrier and a Cu seed layer for Cu electrodeposition. This layer can effectively inhibit the formation of Cu silicide, and it is also applicable to Cu direct electrodeposition. Because the electrical conductivity of the Ru-Al<SUB>2</SUB>O<SUB>3</SUB> layer is relatively high compared to the Cu seed or pure Ru layer, the ohmic drop within the wafer, known as the terminal effect, should be investigated. In this study, the superfilling of Cu on the Ru-Al<SUB>2</SUB>O<SUB>3</SUB> layers and the terminal effect of Cu electrodeposition are reported. Electrodeposition with constant current results in severe variations in both the deposition amount and Cu property within the wafer. Step current electrodeposition is adopted to solve these problems. At the initial stage, a high current density is briefly applied to render enough overpotential on the whole wafer inducing substantial nucleation. This is followed by a low current density for stable growth and superfilling of Cu with a small terminal effect. The changes in superfilling according to the conditions of the first step and the composition of the Ru-Al<SUB>2</SUB>O<SUB>3</SUB> are clarified. Under the optimal conditions, the successful superfilling is obtained with small variation in the deposition amount within the wafer.

Thermoelectric Characteristics of the Sb2Te3 Compound Semiconductor Electrodeposited for Nanowire Applications

김민영,박경원,오태성 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.53 No.1

Antimony-telluride films were fabricated by electrodeposition and their thermoelectric properties were evaluated for nanowire and thin-film applications. The antimony-telluride nanowires were electrodeposited into an Al2O3 template and their growth rates were characterized. The antimony- telluride films with compositions close to the Sb2Te3 stoichiometry and with Seebeck coefficients higher than 250 ㎶/K were obtained by electrodeposition. The maximum Seebeck coefficient and the maximum power factor of the electrodeposited Sb2Te3 were 390 ㎶/K and 30.2 × 10-4 W/K2-m, respectively. With varying the electrodeposition current density from 2.5 mA/cm2 to 7.5 mA/㎠, the average growth rate of the antimony-telluride nanowires increased from 6.6 ㎛/hr to 9.7 ㎛/hr. The antimony-telluride nanowire was polycrystalline and had a bamboo-type grain structure. Antimony-telluride films were fabricated by electrodeposition and their thermoelectric properties were evaluated for nanowire and thin-film applications. The antimony-telluride nanowires were electrodeposited into an Al2O3 template and their growth rates were characterized. The antimony- telluride films with compositions close to the Sb2Te3 stoichiometry and with Seebeck coefficients higher than 250 ㎶/K were obtained by electrodeposition. The maximum Seebeck coefficient and the maximum power factor of the electrodeposited Sb2Te3 were 390 ㎶/K and 30.2 × 10-4 W/K2-m, respectively. With varying the electrodeposition current density from 2.5 mA/cm2 to 7.5 mA/㎠, the average growth rate of the antimony-telluride nanowires increased from 6.6 ㎛/hr to 9.7 ㎛/hr. The antimony-telluride nanowire was polycrystalline and had a bamboo-type grain structure.

총설 : 반도체 소자용 구리 배선 형성을 위한 전해 도금

김명준 ( Myung Jun Kim ),김재정 ( Jae Jeong Kim ) 한국화학공학회 2014 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.52 No.1

Cu interconnection in electronic devices is fabricated via damascene process including Cu electrodeposition. In this review, Cu electrodeposition and superfilling for fabricating Cu interconnection are introduced. Superfilling results from the influences of organic additives in the electrolyte for Cu electrodeposition, and this is enabled by the local enhancement of Cu electrodeposition at the bottom of filling feature formed on the wafer through manipulating the surface coverage of organic additives. The dimension of metal interconnection has been constantly reduced to increase the integrity of electronic devices, and the width of interconnection reaches the range of few tens of nanometer. This size reduction raises the issues, which are the deterioration of electrical property and the reliability of Cu interconnection, and the difficulty of Cu superfilling. The various researches on the development of organic additives for the modification of Cu microstructure, the application of pulse and pulse-reverse electrodeposition, Cu-based alloy superfilling for improvement of reliability, and the enhancement of superfilling phenomenon to overcome the current problems are addressed in this review.

Effects of Organic Additives on Grain Growth in Electrodeposited Cu Thin Film during Self-Annealing

Sung, Minjae,Kim, Hoe Chul,Lim, Taeho,Kim, Jae Jeong The Electrochemical Society 2017 Journal of the Electrochemical Society Vol.164 No.13

<P>The microstructural changes in electrodeposited Cu films during self-annealing is demonstrated in this study. The structural change is strongly influenced by the organic additives in the Cu electrodeposition. The use of either polyethylene glycol (PEG) or bis-(3-sulfopropyl)disulfide (SPS) decreases the Cu(111) grain size of deposited films, as the adsorption of the additives suppresses the surface diffusion of the Cu ions during the electrodeposition. After the electrodeposition, the average grain size of the deposited film was simultaneously increased by 10% in a self-annealing process to reduce the defect energy, which is mainly composed of the surface energy of the grains. Meanwhile, the grain grew 4 times larger than the as-deposited grain size during the self-annealing when both the PEG and SPS were introduced. The drastic grain growth was attributed to the accumulation of a high defect energy in the deposited film. The dynamic interaction between the co-adsorbed PEG and SPS on the Cu surface during the electrodeposition promotes an unoriented dispersion-type deposition, resulting in high-strain energy as well as surface energy. Releasing the strain energy accumulated by the high density of misorientation also leads to the simultaneous growth of Cu(200) grains. (c) 2017 The Electrochemical Society. All rights reserved.</P>

Pulse Electrodeposition of Polycrystalline Si Film in Molten CaCl₂ Containing SiO₂ Nanoparticles

Taeho Lim,Yeosol Yoon The Korean Electrochemical Society 2023 Journal of electrochemical science and technology Vol.14 No.4

The high cost of Si-based solar cells remains a substantial challenge to their widespread adoption. To address this issue, it is essential to reduce the production cost of solar-grade Si, which is used as raw material. One approach to achieve this is Si electrodeposition in molten salts containing Si sources, such as SiO₂. In this study, we present the pulse electrodeposition of Si in molten CaCl₂ containing SiO₂ nanoparticles. Theoretically, SiO₂ nanoparticles with a diameter of less than 20 nm in molten CaCl₂ at 850℃ have a comparable diffusion coefficient with that of ions in aqueous solutions at room temperature. However, we observed a slower-than-expected diffusion of the SiO₂ nanoparticles, probably because of their tendency to aggregate in the molten CaCl₂. This led to the formation of a non-uniform Si film with low current efficiency during direct current electrodeposition. We overcome this issue using pulse electrodeposition, which enabled the facile supplementation of SiO₂ nanoparticles to the substrate. This approach produced a uniform and thick electrodeposited Si film. Our results demonstrate an efficient method for Si electrodeposition in molten CaCl₂ containing SiO₂ nanoparticles, which can contribute to a reduction in production cost of solar-grade Si.

ITO 기판 위에 AC Electrodeposition 에 의해 제조된 CdTe 박막의 구조적 특성

김원희,박재익,김헌정 한국물리학회 2013 새물리 Vol.63 No.3

CdTe is a p-type semiconductor with a band gap of 1.44 eV. We synthesized CdTe thin films by using an AC electrodeposition technique and investigated the optimal synthesis conditions, such as frequency, waveform, and so on, and the structural properties of the thin films. Compared to the DC electrodeposition, where the current flow is prohibited by the electric double layers between the substrate and the solution, the AC technique is found to produce more uniform thin films with better crystallinities. We discuss possible reasons for this. CdTe는 밴드갭 (bandgap)이 1.44 eV인 p형 반도체 물질이다. 우리는 교류전착법 (AC electrodeposition) 으로 CdTe 을 제작하고 이 필름의구조적, 전기적 특성을 주파수, 파형에 변화를 주어 연구하였다. 직류전압에서는 전기이중층에 의해서 전류가 급격하게 감소되어 균일한형태의 박막이 만들어지지 않는 것을 관찰하였다. 이 문제를 해결하고자교류전압을 가하여 박막시료를 합성하였다. 전압, 파형 (삼각파, 사각파,사인파) 그리고 주파수를 변화하여 시료를 만들고 이 시료들에 대하여X-ray diffraction 측정을 하여 CdTe구조의 (1 0 2) 피크 (peak)를관찰하였다.

Effect of pulse electrodeposition parameters on electrocatalytic the activity of methanol oxidation and morphology of Pt/C catalyst for direct methanol fuel cells

Ye, Feng,Xu, Chao,Liu, Guicheng,Yuan, Mengdi,Wang, Zhiming,Du, Xiaoze,Lee, Joong Kee Pergamon 2018 Energy Conversion and Management Vol. No.

<P><B>Abstract</B></P> <P>The electrodeposition technique for preparing direct methanol fuel cell electrodes has been developed to increase the Pt utilization and lower the Pt loading. The performance of the Pt/C electrode for methanol oxidation reaction (MOR) was optimized by adjusting the electrodeposition parameters such as applied electrical signal types, ratios of t<SUB>on</SUB>/t<SUB>off</SUB>, deposition temperatures, and electrolyte concentrations, systematically. Furthermore, the effects of two kinds of additives, i.e. polyethylene glycol (PEG) and sodium dodecyl sulfonate (SDS), on the catalytic performance and morphology of Pt catalyst were investigated for MOR by SEM, XRD, cyclic voltammetry and linear sweep voltammetry. The results show that the optimal Pt catalyst has been prepared by the square wave current method with t<SUB>on</SUB>/t<SUB>off</SUB> of 1 s/5 s at 30 °C in a 1.0 mmol L<SUP>−1</SUP> H<SUB>2</SUB>PtCl<SUB>6</SUB> solution with a 10<SUP>−4</SUP> mmol L<SUP>−1</SUP> PEG additive. Moreover, the effect of the additive type and amount on the formation mechanism of the Pt crystallite morphology has also been discussed. From the results, introducing additives into the deposition solution in the pulse electrodeposition process is useful for designing and fabricating electrocatalytic electrodes for direct methanol fuel cells.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Signals include square wave current and potential, cyclic voltammetry and constant current pulse. </LI> <LI> Effects of four applied electrical signal types on Pt catalytic performance are compared. </LI> <LI> Parameters for Pt electrodeposition in constant current pulse mode are optimized systematically. </LI> <LI> Effect mechanism of additive on growth of Pt catalyst is studied in pulse electrodeposition. </LI> <LI> Optimal condition is t<SUB>on</SUB>/t<SUB>off</SUB> of 1 s/5 s, 30 °C, 1 mmol L<SUP>−1</SUP> H<SUB>2</SUB>PtCl<SUB>6</SUB> solution with 10<SUP>−4</SUP> mmol L<SUP>−1</SUP> PEG. </LI> </UL> </P>

The effects of TEG-based levelers containing different counter anions on Cu electrodeposition

서영란,오정환,이윤재,김명준,이보람,김재정,김영규 한국공업화학회 2016 한국공업화학회 연구논문 초록집 Vol.2016 No.0

In the development of super integrated circuit, through silicon via (TSV) realizes the shortest interconnects between multiple chips. The successful chip performance relies on the defect-free filling of TSV during the Cu electrodeposition, and that is achieved from the bottom-up filling of a trench. Leveler, a convection dependent adsorbent, is selectively adsorbs on the top of feature and inhibits Cu electrodeposition for the formation of the overall planar Cu deposition. In this presentation, the structure-activity relation has been studied with newly synthesized bis-ammonium levelers. The new levelers contain ammoniums at the ends of linear chains, which are varied in length or the presence of ether unit. The electrochemical analyses and the gap filling performance on TSV are examined with the synthesized levelers in order to verify more effective structure of leveler on Cu electrodeposition.