Catalytic characteristics of Ni(B)‑coated YSZ powder by neutral electroless plating

Sa‑Kyun Rha,Mi‑Jai Lee,Youn‑Seoung Lee 한국세라믹학회 2020 한국세라믹학회지 Vol.57 No.3

In this study, an eco-friendly, electroless, and neutral (pH 7.0) process of nickel plating at low temperature (40 °C) was used to develop an anode catalyst for a solid oxide fuel cell (SOFC). Electroless Ni(B) plating on yttria-stabilized zirconia (YSZ) particles resulted in the formation of a Ni(B)/YSZ core–shell. We examined the crystallinity and uniformity of the Ni(B) layer on the plated core–shell powder and found that it had an amorphous-like structure. In addition, we evaluated the rate of carbon deposition and characteristics of the SOFC anode catalyst: the carbon deposition rate was 19.42%, H2 selectivity was nearly 88% at 800 °C, and methane conversion was maintained at 100% at temperatures above 850 °C. It was ascertained that in the high-temperature region, which is the main operating temperature of SOFCs, the amorphous-like microstructure of the Ni(B) layer on the Ni(B)–YSZ core–shell powder played an important role in enhancing these properties.

초고집적소자의 층간절연막용 polysilazane계 spin on glass (SOG)에 관한 연구

나사균,정석철,이재관,김진우,홍정의,이원준 대전산업대학교 반도체기술연구소 2000 半導體技術硏究所報 Vol.2 No.-

초고집적소자의 층간절연막으로서의 polysilazane계 spin on glass (SOG)의 적용 가능성을 평가하였다. 상용화된 무기 SOG 계열의 polysilazane과 polysilazane에 산화제를 첨가하여 SiO_2로의 변환 능력을 향상시킨 물질을 spin coating하고 curing하여 SOG 막을 제조한 다음, 400℃에서 900℃까지의 온도범위에서 열에 SOG막을 형성하여 gapfill 특성을 비교하였으며, SOG막에 contact hole을 형성한 다음 습식 세정에 대한 저항성을 평가하였다. 산화제를 첨가함으로써 polysilazane polymer 구조에서 SiO_2로의 변환이 더욱 효과적으로 이루어져, 기존 SOG 막에 비해 밀도 및 습식세정 chemical에 대한 저항성이 우수하고거 gapfill 특성은 동등한 수준인 SOG 막을 제조할 수 있었다. 특히, 기존의 SOG 막의 경우 좁은 gap space 내에서 curing이 충분하게 이어나지 않아 습식 세정시 hole profile이 나빠지는 문제를 산화제 첨가를 통해 해결할 수 있었다. We have investigated the feasibility of spin on glass (SOG) film from polysilazane-type resin as a premetal dielectric (PMD) layer of the next-generation ultra-large scale integrated (ULSI) devices. A commercial polysilazane resin and a polysilazane-type resin with oxidzing agent were spin-coated and cured to form SOG films. In order to study the effect of oxidizing agent and annealing, the SOG films were characterized as cured and after annealing at 400℃ to 900℃. The density and the resistance against wet chemical of the SOG films were improved by the addition of oxidizing agent, because oxidizing agent enhanced the conversion from polysilazane polymer to siO_2. The hole profile issue associated with insufficient curing of polysilazane innarrow gaps was alao resolved by oxidizing agent, while the gapfill capability of SOG was not deteriorated by oxidizing agent.

Behavior of Boron Implanted into n-Si (100) by Low-Energy (2 keV) Ion Implantation for a Shallow Junction

Sa-Kyun Rha,Youn-Seoung Lee,이명희,Myeung Hee Lee,Min-Seok Jeon,Jun-Kwang Song 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.4

We investigated the behavior of boron by varying the B+ ion implantation energy and the rapid thermal annealing (RTA) temperature. The B+ ions were implanted into n-type Si (100), for which the native oxide layer had been removed. The used B+ ion implantation energies were 0.5 keV, 1 keV and 2 keV. The dose was fixed at 1 × 10 15 atoms/㎠. RTA was performed under a N₂ ambient (760 Torr) at 950℃, 1000℃ and 1050℃ for 10 s. In order to investigate the boron behavior caused by B+ ion implantation, we measured the junction depth Xj, the dose, the sheet resistance Rs and the thickness of silicon oxide layer by using a secondary ion mass spectrometer (SIMS), an ellipsometer, a 4-point probe. By these results, Rs in as-implanted samples increased greatly (from 341 Ω/㎠ to 985 Ω/㎠ for B+ implantation energies of 0.5 keV and 2 keV, respectively) when Xj increased (from 31 nm for 0.5 keV to 57 nm for 2 keV) because of inactivated dopants. After RTA, the diffusion length △Xj was very similar for all ion implantation energies and only changed with variation of the RTA temperature (~35 nm at 950℃, ~65 nm at 1000℃ and ~115 nm at 1050℃)However, Rs changed with variations of the ion implantation energy and the RTA temperature and Rs decreased after annealing (from 182 Ω/㎠ for 0.5 keV to 158 Ω/㎠ for 2 keV at 1050℃). The junction depth Xj depended on the B+ ion implantation energy, but the diffusion length was independent of the B+ ion implantation energy and only depended on the RTA temperature.

Characteristics of Nano-Sized (Pb, La)TiO₃ Powder Synthesized at Room Temperature

Rha, Sa-Kyun,Lim, Borami,Choa, Yong-Ho,Jeon, Min-Seok,Song, Jun-Kwang,Lee, Youn-Seoung American Scientific Publishers 2012 Journal of nanoscience and nanotechnology Vol.12 No.2

Investigation of Eco-friendly Electroless Copper Coating by Sodium-phosphinate

Rha, Sa-Kyun,Lee, Youn-Seoung The Korean Ceramic Society 2015 한국세라믹학회지 Vol.52 No.4

Cu films were plated in an eco-friendly electroless bath (No-Formaldehyde) on Ni/screen printed Ag pattern/PET substrate. For electroless Cu plating, we used sodium-phosphinate ($NaH_2PO_2{\cdot}H_2O$) as reducing agent instead of Formaldehyde. All processes were carried out in electroless solution of pH 7 to minimize damage to the PET substrate. According to the increase of sodium-phosphinate, the deposition rate, the granule size, and rms roughness of the electroless Cu film increased and the Ni content also increased. The electroless Cu films plated using 0.280 M and 0.575 M solutions of sodium-phosphinate were made with Cu of 94 at.% and 82 at.%, respectively, with Ni and a small amount P. All electroless Cu plated films had typical FCC crystal structures, although the amount of co-deposited Ni changed according to the variation of the sodium-phosphinate contents. From these results, we concluded that a formation of higher purity Cu film without surface damage to the PET is possible by use of sodium-phosphinate at pH 7.

Electroless Cu Plating on Anodized Al Substrate for High Power LED.

Rha, Sa-Kyun,Lee, Youn-Seoung American Scientific Publishers 2015 Journal of nanoscience and nanotechnology Vol.15 No.3

<P>Area-selective copper deposition on screen printed Ag pattern/anodized Al/Al substrate was attempted using a neutral electroless plating processes for printed circuit boards (PCBs), according to a range of variation of pH 6.5-pH 8 at 70 °C. The utilized basic electroless solution consisted of copper(II) sulfate pentahydrate, sodium phosphinate monohydrate, sodium citrate tribasic dihydrate, ammonium chloride, and nickel(II) sulfate hexahydrate. The pH of the copper plating solutions was adjusted from pH 6.5 to pH 8 using NH4OH. Using electroless plating in pH 6.5 and pH 7 baths, surface damage to the anodized Al layer hardly occurred; the structure of the plated Cu-rich films was a typical fcc-Cu, but a small Ni component was co-deposited. In electroless plating at pH 8, the surface of the anodized Al layer was damaged and the Cu film was composed of a lot of Ni and P which were co-deposited with Cu. Finally, in a pH 7 bath, we can make a selectively electroless plated Cu film on a PCB without any lithography and without surface damage to the anodized Al layer.</P>

Characterization of TIN barriers against Cu diffusion by capacitance-voltage measurement

Rha, Sa-Kyun,Lee, Seung-Yun,Lee, Won-Jun,Hwang, Yong-Sup,Park, Chong-Ook,Kim, Dong-Won,Lee, Youn-Seoung,Whang, Chung-Nam 대전산업대학교 반도체기술연구소 1999 半導體技術硏究所報 Vol.1 No.-

Sputtered TiN was studied as a diffusion barrier in Cu/TiN/Ti/Si and Cu/TiN/Ti/SiO_2/Si multilayer structures using various characterization methods, and their sensitivities for detecting breakdown of the barrier were compared. It was confirmed by scanning electron microscopy and Auger electron spectroscopy that breakdown of the TiN barrier occurred through out-diffusion of Si in addition to in-diffusion of Cu. Breakdown temperatures varied by more than 100℃ depending on characterization methods, and capacitance-voltage (C-V) measurement was most sensitive for detecting the failure of the TiN barrier. The effects of rapid thermal annealing (RTA) on barrier properties of TiN were investigated, and it was found by C-V measurement that the TiN(400nm) RTA treated at 700℃ in a NH_3 ambient was stable up to 590℃ for 2 h, while the reference TiN (400nm) was stable up to 450℃ for 2 h.

Characteristics of the Ni-B film in printed circuit board for high-power light-emitting diodes.

Rha, Sa-Kyun,Cho, Yang-Rae,Yoon, Jae-Sik,Lee, Youn-Seoung American Scientific Publishers 2013 Journal of Nanoscience and Nanotechnology Vol.13 No.9

<P>To develop metal printed circuit boards for a high-power light-emitting diode package using electroless plated Ni-B films on an all-in-one Al2O3-Al substrate with a 10 nm pore size, the growth mode of an electroless Ni-B film on a screen-printed Ag pattern/Al2O3-Al substrate was studied. So as not to damage the Al2O3-AI substrate, a nearly neutral Ni plating solution bath (pH 6.5) included dimethylamine borane was used. It was confirmed that the Ni-B film was selectively grown on the printed Ag paste layer, without growth on the Al2O3. The structure of the electroless plated Ni-B film was amorphous, and the deposition rate of the film was 1.64 +/- 0.078 nm/sec. According to the increase in plating time, the grain sizes of the electroless plated Ni-B film became bigger, and the surface morphology gradually became flatter. In addition, both the mass difference and the film thickness were changed linearly. From these results, it can be concluded that the electroless Ni-B film on printed Ag paste grows immediately from the beginning, and then grows linearly with increasing plating time.</P>

Improved TiN film as a diffusion barrier between copper and silicon

Rha, Sa-Kyun,Lee, Won-Jun,Lee, Seung-Yun,Hwang, Yong-Sup,Lee, Yoon-Jik,Kim, Dong-Il,Kim, Dong-Won,Chun, Soung-Soon,Park, Chong-Ook 대전산업대학교 반도체기술연구소 1999 半導體技術硏究所報 Vol.1 No.-

Reactively-sputtered TiN films were studied as a copper diffusion barrier in the Cu/TiN/Ti/Si and Cu/TiN/Si and Cu/TiN/Ti/SiO_2/Si multi-layer structures. From the viewpoint of the microstructure of TiN, the diffusion barrier property of TiN against copper improved when the grain boundary of TiN(as the diffusion path of copper) was extended and densified, which was confirmed by the increase of the breakdown temperature of the TiN diffusion barrier detected by various characterization methods. The 40-nm thick Tin with double deposition (extension of the grain boundary of TiN) and stuffing (the densification of the grain boundary of TiN) by RTP treatment (NH_3, 600℃, I min) was found to be stable up to 575℃ for 2 h by the C-V method.

Reactions of Ni-B on printed Ag pattern by using nearly neutral electroless bath.

Rha, Sa-Kyun,Kim, Hyung Chul,Lee, Youn-Seoung American Scientific Publishers 2014 Journal of nanoscience and nanotechnology Vol.14 No.11

<P>In this study, we investigated the characteristics of a nearly neutral Ni source solution including dimethylamine borane (DMAB) used to develop the metal PCB (printed circuit board) of high power LED (light-emitting diode) package. In accordance with the bath temperature ranging from 50 degrees C to 75 degrees C, an electroless Ni-B plating on a screen-printed Ag pattern with an anodized Al substrate was carried out. The depositon rate of the electroless plated Ni-B film at bath temperature ranging from 50 degrees C to 75 degrees C was estimated by measurements of the thickness and the mass. The deposition rates by change of thickness and mass of the electroless plated Ni-B film at 50 degrees C were - 58 nm/min and 0.113 mg/min respectively. The activation energy obtained from slope of Arrhenius plot using these deposition rates was - 59 kJ/mol. Finally, selectively the film growth was achieved at all plating temperatures, without a damage of anodized Al substrate.</P>