The multiple challenges presented by the problem of scaling transistor sizes are all related to the fact that transistors encode binary information by the state of a current switch. What is required is a new paradigm, still capable of providing general purpose digital computation, but which can be scaled down to the ultimate limits of molecular size. The quantum-dot cellular automata (QCA) approach encodes binary signals by the arrangement of charge inside a cell composed of several quantum dots. No current flows from cell to cell or from power supply to ground. A clocking voltage provides energy to produce power gain, which restores signals. It has been shown that logic, memory, and general purpose digital computing can all be implemented in this scheme. Power dissipation is predicted to be low enough to allow integration at the scale of 10^11 devices/cm^2
Craig S. Lent is The Frank M. Freimann Professor of Electrical Engineering at the University of Notre Dame, Notre Dame, Indiana. Prof. Lent received the bachelor's degree in physics from the University of California at Berkeley and his doctorate in Solid State Physics from the University of Minnesota. Prof. Lent has been a member of the Notre Dame faculty since 1986.
POTR 234, Purdue University, West Lafayette, IN