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1

Enhancement of Life Time of the Dimensionally Stable Anode for Copper Electroplating Applications

Son S. H., Park S. C., Lee M. S.

Archives of Metallurgy and Materials

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2017

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Vol. 62, iss. 2B

1019--1022

EN

In order to enhance the long-term stability of DSA for copper electroplating process, in the present study, noble metal oxides with excellent electrochemical properties was used and optimum condition was determined the ratio of noble metal oxides, surface pre-treatment of titanium substrate and heat treatment. The effect of the surface pretreatment of titanium substrate and ratio of noble metal oxides were estimated by accelerated test at the highly current density conditions. The lifetime of DSA increase six-fold higher as the oxide thickness of Ta 7 : Ir 3 composition ratio. Under the optimal condition, surface pretreatment led to dramatic increase in the lifetime of DSA.

2

Study On The Electro-Refining Of Tin In Acid Solution From Electronic Waste

Son S. H., Park S. C., Kim J. H., Kim Y. H., Lee M. S., Ahn J.-W.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1217--1220

EN

The tin metal could be retractable from wasted tin scrap, sludge, and wasted electroplated solution hydrometallurgical treatment, and purification process. In order to be used as resource of electronic devices, the retracted crude metal should be purified to the extent of higher than 99.9%. In this study, tin electro-refining process was performed to purify the casted tin crude metal at various experimental conditions: at the current density of 3, 5A/dm2, and in various electrolytes such as hydrochloric acid, sulfuric acid and methansulfonic acid. Additional experiment was conducted using Rotating Disk Electrode (RDE) in order to investigate the rate determining step of tin electro-refining process. The current efficiency, 65.6%, was achievable at the condition of current density, 5A/dm2, and in the electrolyte of Hydrochloric acid. During tin electro-refining process, impurity dissolved from tin crude metal into the electrolyte was analyzed using Inductively Coupled Plasma Optical Emission Spectrometer (ICP-OES), and the result showed the concentration of impurity metal gradually increased. Quantitative analysis on casted tin crude metal showed that it consists of tin with 93.9 wt.% and several impurity metals of Ag, Bi, Pb, Cu, and etc. After tin electro-refining process, the purity of tin increased up to 99.985 wt.%.

3

Recovery Of Valuable Metals In Tin-Based Anodic Slimes By Carbothermic Reaction

Han C., Kim Y.-M., Son S. H., Choi H., Kim T. B., Kim Y. H.

Archives of Metallurgy and Materials

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2015

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Vol. 60, iss. 2B

1213--1216

EN

This study investigated the recovery of anodic slimes by carbothermic reaction in the temperature range of 973~1,273K and amount of carbon as a function of time. Tin anodic slime samples were collected from the bottom of the electrolytic cells during the electro-refining of tin. The anodic slimes are consisted of high concentrated tin, silver, copper and lead oxides. The kinetics of reduction were determined by means of the weight-loss measurement technique. In order to understand in detail of carbothermic reaction, thermodynamic calculation was carried out and compared with experiments. From thermodynamic calculation and experiment, it was confirmed that Sn-based anodic slime could be reduced by controlling temperature and amount of carbon. However, any tendency between the reduction temperature and carbon content for the reduction reaction was not observed.

4

Characteristics of infrared photodiode using SiO₂ insulator on InSb wafer with p-i-n structure

Cho J. Y., Kim J. S., Son S. H., Lee J. H., Choi S. Y.

Opto-Electronics Review

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1999

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Vol. 7, No. 4

369-374

EN

A highly sensitivite photovoltaic infrared diode was fabricated for detecting a 3-5 µm wavelength range in an InSb wafer with a p-i-n structure grown by MOCVD. The formation of silicon dioxide (SiO₂) insulator films for the junction interface and surface of the photodiode were prepared using remote plasma enhanced chemical vapour deposition (PECVD) as InSb has a low melting point and evaporation temperature for surface atoms. The structural characteristics of SiO₂ films and electrical characteristics of metal-insulator-semiconductor structures were initially examined. The leakage current density at 1 MV/cm was about 22 nA/cm², the breakdown electric field of the MIS capacitor using SiO₂ film deposited at 105°C was about 3.5 MV/cm, and the interface-state density at the mid-band gap extracted from the 1 MHz capacitance-voltage measurement was about 2x10¹¹ cm⁻² eV⁻¹. Thereafter, the characteristics of the infrared photodiode were examined. The product of zero-bias resistance by area (R₀A) showed 1.56 x 10⁶ Ωcm² and normalized detectivity exhibited about 1x10¹¹ cm⁻² W⁻¹.