Impact of Metal Hybridization on Contact Resistance and Leakage Current of Carbon Nanotube Transistors

Carbon nanotube field effect transistors (CNFETs) have potential applications in future logic technology as they display good electrostatic control and excellent transport properties. However, contact resistance and leakage currents could limit scaling of CNFETs. Non-equilibrium Green's function (NEGF) simulation investigates that coupling between contact metal and CNT impacts both contact resistance and leakage current. The physical mechanisms underlying the effects are analyzed. A model with calibrated metal coupling strength from experimental data projects I ON -I OFF design space to understand the trade-off between shrinking contact and extension lengths. For CNT with diameter of 1 nm, both contact and extension lengths greater than 8 nm are a good compromise between I ON and I OFF for digital logic in advanced technology nodes.