Kyung-In Choi

Materials and processes for small fuel cells

Abstract Materials and processes for water management electrode, efficient flow field, low cost ionomer membrane and stack design for proton exchange membrane fuel cell (PEMFC) also with methanol oxidation catalyst, liquid diffusion electrode, low methanol cross-over membrane and efficient monopolar cell pack design for direct methanol fuel cell (DMFC) are discussed. These include the technical achievements of small PEMFC (Membrane and Electrode Assembly (MEA): 400 mW/cm 2 with non-humidified H 2 /air, 1 Bar, 30 °C; membrane: 0.1 S/cm; stack: 40 and 200 W with no peripheral) and miniaturized DMFC (MEA: 50 mW/cm 2 with 2 M methanol and 1 Bar air at 30 °C; membrane: hybrid; cell pack: 600 mW). Further studies for the realization of these technologies are also suggested.

A robust alternative for the DRAM capacitor of 50 nm generation

As a new alternative for the DRAM capacitor of 50 nm generation, Ru/Insulator/TiN (RIT) capacitor with the lowest Toxeq of 0.85 nm has been successfully developed for the first time. TiO/sub 2//HfO/sub 2/ and Ta/sub 2/O/sub 5//HfO/sub 2/ double-layers were used as dielectric materials. After full integration into 512 Mbits DRAM device, the RIT capacitor showed good electrical properties and thermal stability up to 550/spl deg/C and its time-dependent-dielectric-breakdown behavior sufficiently satisfied 10-year lifetime within a DRAM operation voltage.

Advanced Al Damascene Process for Fine Trench Under 70nm Design Rule

Due to a rapid shrinkage in memory devices, backned of the line process experiences great difficulties, especially Al metallization. Furthermore, there is a continuous demands in low line resistance in order to promote device performances. In this article, Al damascene process is proposed as compared to Al patterning process, which suffers from inherent pattering issue at a fine pitch under 70nm. The most difficulties in the development of Al damascene process were to form a stable and void free Al in fine trench and to obtain scratch and corrosions free Al surface. In this study, 50nm beyond fill was successfully achieved by “bottom up growth” of CVD Al. For the process, CVD Al by using Methylpyrroridine Alane (MPA) precursor was deposited on a stacked film of CVD TiN and PVD TiN as a wetting layer, which was followed by PVD Al and reflow, then the Al surface was polished with colloidal silica based slurry. In addition, electrical property of Al scheme and W scheme was compared with damascene pattern, along with which we demonstrated that around 36% decrease in parasitic capacitance is achievable by decrease of metal line height from 3500A to 1000A on simulation test implying that device performance could be enhanced.

The effect of oral glutamine supplement (OGS) on fluorouracil (5-FU) induced intestinal mucosal damage (IMD) assessed by intestinal permeability (IP) test

8050 Background: Systemic chemotherapy may damage gastrointestinal epithelium. IMD and mucositis are one of the most common side effect of chemotherapy. However, there is not a tool for direct measurement of IMD. IMD is associated with increased IP. It is known that IP test with chromium-ethylenediaminetetraacetic acid (51Cr-EDTA) is a useful tool to assess the IMD. Glutamine is the energy source for gastrointestinal epithelium. OGS may have a role in the prevention of chemotherapy induced IMD and mucositis. The aims of this study were to evaluate the relationship between the urinary excretion of 51Cr-EDTA and the severity of IMD and mucositis, and the effect of OGS on 5-FU induced IMD and mucositis. METHODS Fifty one patients with advanced cancer received 5-FU based chemotherapy. Eighteen healthy volunteers were in the control group. IP was assessed by measurement of the urinary excretion of 51Cr-EDTA after oral challenge, on days 6-12 after chemotherapy. Among fifty one patients, twenty two patients received OGS (30 g/day) and twenty nine only best supportive care (BSC). OGS was continued for 15 days. It was started at least three days before chemotherapy. mucositis was graded according to the National Cancer Institute common toxicity criteria. RESULTS In the chemotherapy group, the mean value of IP test was significantly higher than in the control group (8.68±6.55% vs 1.99±0.53%, respectively, p<0.001). The severity of oral mucositis was correlated with the value of IP test ( p<0.001, r= 0.792). In the OGS group, the mean value of IP test was significantly lower than in the BSC group (5.44±3.42% vs 11.26±7.24%, respectively, p=0.001). In the OGS group, grade II-IV of mucositis was observed in the six patients(10%), and in the eleven patients (38%) in the BSC group. (p<0.001). CONCLUSIONS The IP test may be a useful tool for assessing IMD and mucositis. OGS may have a protective effect on 5-FU based chemotherapy induced IMD and mucositis. Further studies are needed to define the role of OGS in chemotherapy induced IMD and mucositis. No significant financial relationships to disclose.