1. Department of Nanoscale Semiconductor Engineering; Hanyang University; Seoul 133-791 Korea
2. Division of Materials Science and Engineering; Hanyang University; Seoul 133-791 Korea
3. FAB Manufacturing Division; SK Hynix, Inc.; 2091, Gyeongchung-Daero Bubal-Eub, Icheon-Si Gyeonggi-Do 167-701 Korea
4. Department of Materials Science and Engineering; Ajou University; Suwon 443-739 Korea
5. Department of Energy Systems Research; Ajou University; Suwon 443-739 Korea