1. Department of Nano Semiconductor EngineeringKorea University1, 5‐ka, Anam‐dongSeongbuk‐guSeoul136‐713Republic of Korea
2. SK Hynix Semiconductor Inc.Icheon, Seongbuk‐guGyeongggi‐do467‐701Republic of Korea
3. Department of Electrical EngineeringKorea University1, 5‐ka, Anam‐dongSeongbuk‐guSeoul136‐713Republic of Korea