Qiang Zhao is a master's student in microelectronics and solid-state electronics at Harbin Institute of Technology, China. His research interests include high-speed and low-power VLSI design and reliability in semiconductor devices. Zhao has a BS in electronic science and technology from the Harbin Institute of Technology. Direct questions and comments about this article to Jing Guo, Microelectronics Center, Harbin Institute of Technology, Harbin, HLJ 150001, China;