Carbon Nanotube Transistors with 60mV/decade Switching and its Capacitance Measurement

Recently, we have been able to approach the ultimate vertical scaling limit of carbon nanotube field effect transistors (FETs) and reliably achieve S ~ 60 mV/decade at room temperature, by non-covalent functionalization of single walled carbon nonotubes (SWNTs) with ploy-T DNA molecules, which can impart functional groups of sufficient density and stability for uniform and conformal ALD of high-? dielectrics (HfO2) with thickness down to 2-3 nm on SWNTs. Moreover, the small top gate stack capacitance (~300aF/um) of the SWNT FET has been successfully measured directly, using a special technique. The mobility of the SWNT FETs at room temperature is also extracted by the capacitance measured directly.