A CARBON NANOTUBE FIELD EFFECT TRANSISTOR BASED DIGITAL TO ANALOG CONVERTER

摘要

With the imminent CMOS fabrication process saturation, there is a need to explore alternative `beyond-CMOS technologies for the design of futuristic electronic circuits: both analog and digital. The present invention is one such attempt to design a Digital-to-Analog Converter (DAC) in a viable alternative to the conventional CMOS technology viz. the Carbon Nanotube Field Effect Transistor (CNFET) technology, wherein instead of varying the current a transistor by setting the aspect ratio, the current is set by setting the number of carbon nanotubes (CNT) in the channel region of the CNFET. An appropriate selection of the CNT count for different transistors leads to differently scaled currents in the transistors. The bit vales in the digital input are then utilized to control the on/off state of these transistors, leading to a digitally controlled output current (and an equivalent voltage ) being available at the output. The technique may be readily extended to more number of stages i.e. more number of bits in the digital input.