Scaling of MOSFETs and CMOS has limitations in fabrication and performance due to increased short channel effects, reduced gate control, leakage currents, severe process variations, etc.

It is essential to study new materials & devices to replace silicon in nano scaled transistors.

Carbon nanotube transistors seem to be the promising device for nano technology.

a carbon nanotube field effect transistor is a FET whose channel is made up of a single nanotube or an array of carbon nanotubes instead of bulk silicon as in the traditional MOSFET structure.

A carbon nanotube is a graphene sheet with carbon atoms appearing in hexagonal patterns rolled up to form a hollow cylinder also known as rolled up chicken wire structure.

CNTs tubular cylinders of carbon atoms that have extraordinary mechanical, electrical, thermal optical and chemical properties.

The structure and operation of CNT transistor is similar to conventional MOSFET with difference in channel material which is formed with CNT wire instead of silicon structure of it is as shown below.

The fabrication process of CNT transistor is as follows –