Highly doped and optimized 5-nm GAA CNTFET with different perspectives

Abstract

The invention of new transistors and their channel length reduction are challenging processes. The carbon nanotube field-effect transistor (CNTFET), especially the gate-all-around (GAA) type, is an encouraging technology to solve the short channel effect. In this paper, changing doping concentration and finding the best coordination for contacts and spacer are promising approaches that are discussed. A highly doped 5 nm GAA CNTFET is presented and its functionality is evaluated in the device, layout, and circuit states. By the Monte Carlo method, the best structure coordination of drain and source contacts, spacer, width, and height are extracted. The device is evaluated for different supply voltages and the best voltage for its operation is 0.5 V. The concentration of dopants for n-type devices is found to be N_D0 = 1 × 10²¹ cm⁻³ and N_A = 1 × 10¹⁸ cm⁻³ for the donor and acceptor, respectively, and for the p-type, N_A and N_D0 are replaced. Also, the I_on/I_OFF ratio of n-type and p-type are 2.3 × 10⁴ and 1.6 × 10⁴, respectively, which are achieved by double optimization. The optimized devices are implemented in an inverter. The resulting noise margin of the inverter demonstrates its high accuracy. The customized device is a qualified candidate for sophisticated structures.