Carbon nanotube capacitors arrays using high-k dielectrics

The electrical characteristics and fabrication process of nanocapacitor arrays using metal-high-k dielectric-carbon nanotube-metal layers (MICntM) were studied. MWCNTs arrays were fabricated using an electron beam lithography based lift-off process for catalyst definition and the high-k dielectric layer, hafnium oxide (HfO2), was deposited using rf magnetron sputtering. The MICntM structures show high capacitance and the compatibility with high-k dielectric material and its deposition processes. MICntM capacitors arrays with sputtered HfO2 show specific capacitance of 0.62 μF/cm2. The leakage current density at 1 V is less than 5 μA/cm2. The high aspect ratio of MWCNTs increases the effective electrode area and HfO2 allows higher permittivity, hence, higher capacitance structures are realized.