Fabrication of a Single Carbon Nano Tube for use in Nanolithography of MOSFET Gate

Vertically aligned carbon nanotubes were grown by DC-PECVD on (100) cleaned Si using a mixture of Methane and hydrogen as the feed gases. For having single and small CNTs, we have used a refinement process, by means a seed layer is patterned by the standard lithography method. It forms islands of Cobalt for subsequent growth of nanotubes. By consecutive repetition of exposure/growth steps single and isolated islands of cobalt can be formed so that single standing vertical tubes are fabricated. The grown nanotubes are encapsulated by an insulating TiO₂ layer and in result; Straight lines with width between 40 to 120 nm have been successfully drawn by these CNTs. The applied voltage between anode and cathode for electron emission from CNTs is 100 volts in 100 mum distance. This technique has been applied on P-type 00(100) silicon substrates for the formation of the gate region of N- MOSFET devices. The resulted transistor has a drive current of 286 muA/ mu m in VGs=250 mV and a maximum g_m equal to 2100 mS/mm with sub-threshold slope of 100 mv/decade.