Quantum Dots Leap Leap Ahead of the SIA Roadmap !
The SIA (Semiconductor Industry Association) roadmap projects a continuing miniaturization of Silicon semiconductor devices for the next 15 years. Large research investments will overcome problems with lithography and materials and Silicon technology will be pushed towards nanometer scale transistor structures (Figure 1a). However, as the device sizes are reduced the number of carriers involved in the operation of a single device is reduced as well (Figure 1b). In fact, state-of-the-art semiconductor structures will soon be plagued by dopant fluctuation and particle noise problems as well as quantum mechanical effects such as state discretization and tunneling. Quantum dots are beyond the SIA roadmap, since it remains focused silicon scaling. However, QDs do offer near-term applications to far infrared detectors and sources in other material systems. In fact QDs have been developed since the late 80's and several implementations have already reached room temperature operation. Quantum dot device and circuit concepts utilize rather than fight the discreteness of the electron charge and they offer a possible breakthrough in device and circuit technology.