"Moore's Law" states that the number of transistors in an integrated circuit will double approximately every two years. True to this observation, the number of transistors per Si IC indeed has doubled every 18 months since the 1970s. In accordance with the scaling trend predicted in Moore's Law, not only is the packing density of transistors increased but devices' performance are significantly improved as well. However as the size of transistors continuously shrinks, several issues such as the fundamental limitation of Si, quantum