Semiconducting nanowire transistors with wrap-gates


Field effect transistors (FETs) are switches that form the basis for electronics all around us - from high performance computers to mobile devices. A field effect transistor is like a tap, or a valve, where the turning of the tap knob controls the flow of water. In the case of transistor the gate electrode is the knob that modifies the flow of electrons between two terminals called the source and the drain. In order to make faster transistors that operate at high frequencies one has to make them really small, and also be able to rapidly turn off and on the flow of electric current which requires an efficient gate electrode. Such devices are fabricated from tiny semiconductor nanowires, 1000 times narrower than a human hair, and need to have gate electrodes with a high capacitive coupling to the semiconducting channel that connects the source and the drain electrodes. These
devices are important not only from technological standpoint of future devices but are also interesting as they provide a unique platform to study the nature of the quantum mechanical behaviour of electrons flowing in a nanowire.

We have shown that this efficient gate for a nanowire can be fabricated rather simply using technology that is compatible with today's fabrication technology. This technique can have a significant impact on how the transistors will be fabricated in the future. This work is the result of a close collaboration between two groups with expertise in Nanoelectronics and Semiconductor
. The article reporting this work was featured on the cover of the journal Applied Physics Letters and also in Nature News and Views, Nature 481, 152 (2012).