• Title/Summary/Keyword: substrate thickness

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Effect of Different Aging Times on Sn-Ag-Cu Solder Alloy

  • Ervina Efzan, M.N.;Siti Norfarhani, I.
    • Transactions on Electrical and Electronic Materials
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    • v.16 no.3
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    • pp.112-116
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    • 2015
  • This work studied the thickness and contact angle of solder joints between SAC 305 lead-free solder alloy and a Copper (Cu) substrate. Intermetallic compound (IMC) thickness and contact angle of 3Sn-Ag-0.5Cu (SAC 305) leadfree solder were measured using varying aging times, at a fixed temperature at 30℃. The thickness of IMC and contact angle depend on the aging time. IMC thickness increases as the aging increases. The contact angle gradually decreased from 39.49° to 27.59° as aging time increased from zero to 24 hours for big solder sample. Meanwhile, for small solder sample, the contact angle increased from 32.00° to 40.53° from zero to 24 hours. The IMC thickness sharply increased from 0.007 mm to 0.011 mm from zero to 24 hours aging time for big solder. In spite of that, for small solder the IMC thickness gradually increased from 0.009 mm to 0.017 mm. XRD analysis was used to confirm the intermetallic formation inside the sample. Cu6Sn5, Cu3Sn, Ni3Sn and Ni3Sn2 IMC layers were formed between the solder and the copper substrate. As the aging time increased, the strength of the solder joint mproved due to reduced contact angle.

A Study on the Evaluation of Piezoelectric Thin Film Characteristics in Composite Resonator Structure Using Resonance Spectrum Method (공진주파수 스펙트럼법을 이용한 Composite Resonator 구조에서 압전박막의 특성 평가에 대한 연구)

  • Choi Joon Young;Chang Dong Hoon;Kang Seong Jun;Yoon Yung Sup
    • Journal of the Institute of Electronics Engineers of Korea SD
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    • v.42 no.1
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    • pp.9-17
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    • 2005
  • We studied the characteristics of impedance and electromechanical coupling coefficient in ZnO and AIN thin films by using resonance frequency spectrum method. The response peak of impedance decreased with the decrease of thickness of piezoelectrics, the number of mode of response peak decreased with the decrease of substrate thickness. An error of Kt² estimated from input Kt² increased as the thickness of piezoelectrics decreased and the thickness of substrate increased. Also, the error was increased in case of a large acoustic impedance of substrate. It was found that the composite resonator operating in optimized condition could be designed through the resonance frequency spectrum analysis of composited resonator consisted of piezoelectric thin film and substrate.

Study on Depositing Oxide Films on Ni Substrate for Superconducting Tape (초전도 테이프 제작을 위한 니켈기판 상의 산화물 박막 증찰)

  • Kim, Ho-Sup;Shi, Dongqui;Ko, Rock-Kil;Chung, Jun-Ki;Ha, Hong-Soo;Song, Kyu-Jeong;Park, Chan
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.17 no.12
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    • pp.1356-1361
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    • 2004
  • High temperature superconducting coated conductor has a structure of ///. The buffer layer consists of multi-layer, this study reports the deposition method and optimal deposition conditions of YSZ(Yttria-stabilized zirconia) layer which plays a important part in preventing the elements of substrate from diffusing into the superconducting layer. YSZ layer was deposited by DC reactive sputtering technique using water vapor for oxidizing deposited elements on substrate. To investigate optimal thickness of YSZ film, four YSZ/CeO$_2$/Ni samples with different YSZ thickness(130 nm, 260 nm, 390 nm, and 650 nm) were prepared. The SEM image showed that the surface of YSZ layer was getting to be rougher as YSZ layer was getting thicker and the growth mode of YSZ layer was columnar grain growth. After CeO$_2$ layer was deposited with the same thickness of 18.3 nm on each four samples, YBCO layer was deposited by PLD method with the thickness of 300 nm. The critical currents of four samples were 0, 6 A, 7.5 A, and 5 A respectively. This shows that as YSZ layer is getting thicker, YSZ layer plays a good role as a diffusion barrier but the surface of YSZ layer is getting rougher.

Fabrication of surface-enhanced Raman scattering substrate using black silicon layer manufactured through reactive ion etching (RIE 공정으로 제조된 블랙 실리콘(Black Silicon) 층을 사용한 표면 증강 라만 산란 기판 제작)

  • Kim, Hyeong Ju;Kim, Bonghwan;Lee, Dongin;Lee, Bong-Hee;Cho, Chanseob
    • Journal of Sensor Science and Technology
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    • v.30 no.4
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    • pp.267-272
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    • 2021
  • In this study, Ag was deposited to investigate its applicability as a surface-enhanced Raman scattering substrate after forming a grass-type black silicon structure through maskless reactive ion etching. Grass-structured black silicon with heights of 2 - 7 ㎛ was formed at radio-frequency (RF) power of 150 - 170 W. The process pressure was 250 mTorr, the O2/SF6 gas ratio was 15/37.5, and the processing time was 10 - 20 min. When the processing time was increased by more than 20 min, the self-masking of SixOyFz did not occur, and the black silicon structure was therefore not formed. Raman response characteristics were measured based on the Ag thickness deposited on a black silicon substrate. As the Ag thickness increased, the characteristic peak intensity increased. When the Ag thickness deposited on the black silicon substrate increased from 40 to 80 nm, the Raman response intensity at a Raman wavelength of 1507 / cm increased from 8.2 × 103 to 25 × 103 cps. When the Ag thickness was 150 nm, the increase declined to 30 × 103 cps and showed a saturation tendency. When the RF power increased from 150 to 170 W, the response intensity at a 1507/cm Raman wavelength slightly increased from 30 × 103 to 33 × 103 cps. However, when the RF power was 200 W, the Raman response intensity decreased significantly to 6.2 × 103 cps.

Vibration based energy harvesting performance of magneto-electro-elastic beams reinforced with carbon nanotubes

  • Arjun Siddharth Mangalasseri;Vinyas Mahesh;Sriram Mukunda;Vishwas Mahesh;Sathiskumar A Ponnusami;Dineshkumar Harursampath;Abdelouahed Tounsi
    • Advances in nano research
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    • v.14 no.1
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    • pp.27-43
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    • 2023
  • This article investigates the energy harvesting characteristics of a magneto-electro-elastic (MEE) cantilever beam reinforced with carbon nanotubes (CNT) under transverse vibration. To this end, the well-known lumped parameter model is used to represent the coupled multiphysics problem mathematically. The proposed system consists of the MEE-CNT layer on top and an inactive substrate layer at the bottom. The substrate is considered to be made of either an isotropic or composite material. Basic laws such as Gauss's Law, Newton's Law and Faraday's Law are used to arrive at the governing equations. Surface electrodes across the beam are used to harvest the electric potential produced, together with a wound coil, for the generated magnetic potential. The influence of various distributions of the CNT and its volume fraction, substrate material, length-to-thickness ratio, and thickness ratio of substrate to MEE layer on the energy harvesting behaviour is thoroughly discussed. Further, the effect of external resistances and changes in substrate material on the response is analysed and reported. The article aims to explore smart material-based energy harvesting systems, focusing on their behaviour when reinforced with carbon nanotubes. The results of this study may lead to an improved understanding of the design and analysis of CNT-based smart structures.

Study on Thickness of Porous Silicon Layer According to the Various Anodization Times

  • Jang, Seunghyun
    • Journal of Integrative Natural Science
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    • v.3 no.4
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    • pp.206-209
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    • 2010
  • As the etching time is varied, the change of thickness of the porous silicon layers was successfully investigated. The thickness of the PSi layer as a function of anodization time for a p-type substrate that is etched at a constant current density of 50 $mA/cm^2$ in a 35% hydrofluoric acid solution shows a linear relationship between the etching time and the thickness of the PSi layer.

Ta Doped SnO2 Transparent Conducting Films Prepared by PLD

  • Cho, Ho Je;Seo, Yong Jun;Kim, Geun Woo;Park, Keun Young;Heo, Si Nae;Koo, Bon Heun
    • Korean Journal of Materials Research
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    • v.23 no.8
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    • pp.435-440
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    • 2013
  • Transparent and conducting thin films of Ta-doped $SnO_2$ were fabricated on a glass substrate by a pulse laser deposition(PLD) method. The structural, optical, and electrical properties of these films were investigated as a function of doping level, oxygen partial pressure, substrate temperature, and film thickness. XRD results revealed that all the deposited films were polycrystalline and the intensity of the (211) plane of $SnO_2$ decreased with an increase of Ta content. However, the orientation of the films changed from (211) to (110) with an increase in oxygen partial pressure (40 to 100 mTorr) and substrate temperature. The crystallinity of the films also increased with the substrate temperature. The electrical resistivity measurements showed that the resistivity of the films decreased with an increase in Ta doping, which exhibited the lowest resistivity (${\rho}{\sim}1.1{\times}10^{-3}{\Omega}{\cdot}cm$) for 10 wt% Ta-doped $SnO_2$ film, and then increased further. However, the resistivity continuously decreased with the oxygen partial pressure and substrate temperature. The optical bandgap of the 10 wt% Ta-doped $SnO_2$ film increased (3.67 to 3.78 eV) with an increase in film thickness from 100-700 nm, and the figure of merit revealed an increasing trend with the film thickness.

Reactive sputtered tin adhesion for wastewater treatment of BDD electrodes (TiN 중간층을 이용한 수처리용 BDD 전극)

  • KIM, Seo-Han;KIM, Shin;KIM, Tae-Hun;SONG, Pung-Keun
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2017.05a
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    • pp.69-69
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    • 2017
  • For several decades, industrial processes consume a huge amount of raw water for various objects that consequently results in the generation of large amounts of wastewater. There effluents are mainly treated by conventional technologies such are aerobic, anaerobic treatment and chemical coagulation. But, there processes are not suitable for eliminating all hazardous chemical compounds form wastewater and generate a large amount of toxic sludge. Therefore, other processes have been studied and applied together with these techniques to enhance purification results. These techniques include photocatalysis, absorption, advanced oxidation processes, and ozonation, but also have their own drawbacks. In recent years, electrochemical techniques have received attention as wastewater treatment process that show higher purification results and low toxic sludge. There are many kinds of electrode materials for electrochemical process, among them, boron doped diamond (BDD) attracts attention due to good chemical and electrochemical stability, long lifetime and wide potential window that necessary properties for anode electrode. So, there are many researches about high quality BDD, among them, researches are focused BDD on Si substrate. But, Si substrate is hard to apply electrode application due to the brittleness and low life time. And other substrates are also not suitable for wastewater treatment electrode due to high cost. To solve these problems, Ti has been candidate as substrate in consideration of cost and properties. But there are critical issues about adhesion that must be overcome to apply Ti as substrate. In this study, to overcome this problem, TiN interlayer is introduced between BDD and Ti substrate. TiN has higher electrical and thermal conductivity, melting point, and similar crystalline structure with diamond. The TiN interlayer was deposited by reactive DC magnetron sputtering (DCMS) with thickness of 50 nm, $1{\mu}m$. The microstructure of BDD films with TiN interlayer were estimated by FE-SEM and XRD. There are no significant differences in surface grain size despite of various interlayer. In wastewater treatment results, the BDD electrode with TiN (50nm) showed the highest electrolysis speed at livestock wastewater treatment experiments. It is thought to be that TiN with thickness of 50 nm successfully suppressed formation of TiC that harmful to adhesion. And TiN with thickness of $1{\mu}m$ cannot suppress TiC formation.

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Ni-Al Based Intermetallics Coating Through SHS using the Heat of Molten Aluminum (알루미늄 주물 위 용탕열을 이용한 N-Al계 금속간화합물의 연소합성 코팅)

  • Lee, Han-Young;Cho, Yong-Jae
    • Journal of Korea Foundry Society
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    • v.31 no.2
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    • pp.83-86
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    • 2011
  • Ni-Al based intermetallic compounds of self-propagating high-temperature synthesis (SHS) by the heat of molten aluminum and been coated on the aluminum casting alloy. The effects of the pouring temperature in casting and the thickness of casting substrate on SHS of the coating layer have been investigated. The experimental result showed that the reaction of the coating layer was activated with increasing the pouring temperature in casting and the thickness of casting substrate. However, the aluminum substrate was re-melted by the heat of formation for intermetallic compounds. Then, it was considered that some mechanical or thermal treatments for elemental powder mixtures were required to control the heat of formation for intermetallic compounds in advance.

Order-to-disorder Behavior of Block Copolymer Films

  • Ryu, Du-Yeol;Kim, Eun-Hye;Choe, Seung-Hun
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2011.05a
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    • pp.6.2-6.2
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    • 2011
  • Block copolymer (BCP) self-assembly in a film geometry has recently been the focus of increased research interest due to their potential use as templates and scaffolds for the fabrication of nanostructured materials. The phase behavior in a thin film geometry that confines polymer chains to the interfaces will be influenced by the interfacial interactions at substrate/polymer and polymer/air and the commensurability between the equilibrium period (L0) of the BCP and the total film thickness. We investigated the phase transitions for the films of block copolymers (BCPs) on the modified surface, like the order-to-disorder transition (ODT) by in-situ grazing incidence small angle x-ray scattering (GISAXS) and transmission electron microscopy (TEM). The selective interactions on the surface by a PS-grafted substrate provide the preferential interactions with the PS component of the block, while a random copolymer (PS-r-PMMA) grafted substrate do the balanced interfacial interactions on the surface. The thickness dependence of order-to-disorder behavior for BCP films will be discussed in terms of the surface interactions.

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