Silicon single-electron devices and their applications

Single-electron devices (SEDs) are attracting a lot of attention as devices for future large-scale integration because of their inherent low power and small size. It is well known that SEDs have to have small islands together with tunnel barriers at both ends, which makes it difficult to make them. We have developed a novel method of fabricating small Si single-electron transistors (SETs) called pattern-dependent oxidation (PADOX) and used it to make many kinds of SEDs. The low power consumption of SEDs is useful for logic circuits. In addition, SETs have two unique features that conventional transistors do not have: multi-gate capability and conductance that oscillates as a function of gate voltage. We exploit these features to achieve complicated functions for logic circuits, such as multiple-valued logic.