Manipulation of elementary charge in a silicon charge-coupled device.

The ultimate limit in the operation of an electronic device is the manipulation of a single charge. Such a limit has been achieved in single-electron tunnelling devices. However, these devices are based on multiple tunnel barriers and conductive islands, which are complex structures to fabricate. Here we demonstrate another type of device that can also manipulate elementary charge, but which is more suitable for large-scale integration. The device consists of two closely packed silicon wire-MOSFETs, which are commonly used building blocks of electronic circuits. We have developed a scheme to generate and store holes in the channels of either of these MOSFETs. Subsequently, holes can be transferred between the two MOSFETs at the level of an elementary charge, and their exact position can be monitored. This single-charge transfer device, which is operated at 25 K, is in effect a charge-coupled device. This is also the first realization of a silicon-based device that manipulates elementary charge.