Carbon Nanotube Contact Plug on Silicide for CMOS Compatible Interconnect

Carbon nanotube (CNT) filled contact plugs with silicide as the bottom electrode have been demonstrated in this letter. Nickel has been used as the main catalyst to achieve CMOS compatibility. By modifying the catalyst from a pure Ni single layer structure to a Ni/Al/Ni multilayer composite, uniform selective CNT growth on Ti silicide substrate has been achieved. At a low temperature of 450 °C, the vertically aligned CNTs with a density of $1.1\times 10^{11}$ tubes/cm2 inside the silicon dioxide contact plug are formed without the need of catalyst patterning. Four-point Kelvin structures are designed to measure the resistance of the CNT filled contact plugs. Measurement results show that an ohmic contact plug resistance of 216 $\Omega \cdot \mu \text{m}^{2}$ is obtained.