S. D. Kim

Improvement in electrical insulating properties of 10-nm-thick Al2O3 film grown on Al/TiN/Si substrate by remote plasma annealing at low temperatures

The electrical conduction properties of 10-nm-thick atomic-layer deposited Al2O3 thin films with Al bottom and Pt top electrodes were characterized for use in field emission display. The as-deposited films, grown at 300 °C, exhibited such a high electrical leakage that their electrical properties could not be measured. However, post-treatment at 300 °C under a remote O2 or H2O plasma for 30 min improved the insulating properties of the Al2O3 films. However, the electrical conduction mechanism, particularly in the high field (>4 MV/cm) was not Fowler–Nordheim (F–N) tunneling but was influenced by space charge limited conduction implying that there were many traps inside the dielectric film or the electrode interfaces. Postannealing of the top electrode at 300 °C in an oxygen atmosphere resulted in a F–N conduction mechanism by removing the interfacial traps. The calculated barrier height at the Al/Al2O3 interface from the F–N fitting of the current density versus voltage curves using the electron effective...

Assessment of dry etching damage in permalloy thin films

Permalloy (Ni81Fe19) thin films are etched by ion beam etching (IBE) or reactive ion etching (RIE), and the variation of magnetic properties with etching time is investigated. Magnetic softness of permalloy thin films deteriorates as etching proceeds, i.e., film thickness decreases. Coercivity begins to increase steeply at a thickness of 0.4 μm and reaches 16 Oe for IBE and 8 Oe for RIE at 0.09 μm. Effective magnetization is increased by 0.2 kG with IBE but decreased by 0.7 kG with RIE. From an atomic force microscopy analysis and independent wet etching experiments, the increase of coercivity is proved to be attributed to the increase of surface roughness as a result of etching. Etching-induced defects are also responsible for the increase of coercivity, which is confirmed by a measurement of electrical resistivity and x-ray diffraction analysis. Ion beam etching process appears to affect magnetic properties to a greater extent than reactive ion etching process.

Effects of sevoflurane on QT parameters in children with congenital sensorineural hearing loss

Sevoflurane prolongs the QT interval (QTI). Patients with congenital sensorineural hearing loss (SNHL) often have a prolonged QTI. This study was to investigate the effects of sevoflurane on the QTI in SNHL and control children. Thirty patients with SNHL and 30 controls were studied. The corrected QT interval (QTc), interval from peak to end of T wave (Tp‐e) and QT variability index (QTVI) were analysed. QTc and Tp‐e were estimated by the average QTc and Tp‐e measured beat‐by‐beat for 15 min. Heart rate power spectral analysis was performed. In both groups, QTc and QTVI increased during anaesthesia, but Tp‐e did not change. There were no differences in QTc, QTVI, Tp‐e, low‐ and high‐frequency power between the two groups. In both groups, sevoflurane lengthened the QTc and QTVI intervals but not Tp‐e.

Appropriate laryngeal mask airway size for overweight and underweight children

The aim of this study was to compare conventional laryngeal mask airway sizing by weight with sizing by age in over‐ or underweight children. We studied 26 overweight (body mass index > 85th centile) and 26 underweight (body mass index < 15th centile) children. After general anaesthesia was induced, laryngeal mask airways sized by the patient’s weight and by an ideal weight (estimated from the patient’s age according to standardised tables) were inserted consecutively. In overweight children, oropharyngeal leak pressure was significantly greater when the laryngeal mask was sized by the patient’s actual weight. On the other hand in underweight children, it was significantly greater when sized by the ideal weight. In conclusion, laryngeal mask airway sizing according to the manufacturer’s weight‐based recommendation is to be preferred in overweight children, but laryngeal mask airway size by an ideal weight estimated from the patient’s age is a better choice in underweight children.

Ferromagnetic resonance of dry etched permalloy thin films

Permalloy thin films deposited by rf magnetron sputtering are ion beam etched or reactive ion etched. Effects of the dry etching on magnetic properties are examined by ferromagnetic resonance and the results are shown as a function of film thickness (etching time). The perpendicular resonance field shifts toward a higher field as ion beam etching proceeds, but it moves to a lower field in the case of reactive ion etching. The effective magnetization of ion beam etched thin films is slightly increased, but the opposite behavior is observed in reactive ion etched thin films. The exchange stiffness constant decreases gradually with ion beam etching whereas a sudden drop to about 5/spl times/10/sup -7/ erg/cm occurs by reactive ion etching. This result can be explained by a surface etching-damaged layer.

Impacts of geographical location and construction type on as-built roughness in highway pavement construction

This paper investigates the impacts of geographic location (urban and rural) and construction type (reconstruction, resurfacing and replacement) on as-built roughness using explanatory data analysis (EDA) and panel data analysis (PDA). Sets of roughness measurements, International Roughness Index (IRI), and other data for reconstructed, replaced, and resurfaced pavement projects in Wisconsin, U.S.A. from 1998 and 2000 were used for the analysis. This research developed the panel fixed effect model to define significant factors and quantify the interactive impacts of geographic location and construction type. The results show that geographic location is strongly significant, but construction type is not in both EDA and PDA. The likelihood ratio test (LRT) and other empirical analysis also supports that the geographic location is strongly significant factor affecting as-built IRI. The overall results quantify the interactive changes of IRI are 0.129 and 0.178 by PDA and EDA, respectively.