Staying on Moore’s curve by enhancing materials

As the semiconductor industry is moving to more advanced technology nodes, simple scaling of device dimensions and voltages, which worked so well for many decades, is no longer sufficient to continue improving circuit performance. New materials are being introduced and the existing ones are modified to optimize their properties. High dielectric constant (high k) insulators are being developed as an alternative to ultrathin SiO2 for application as gate insulators. Metal gates or FUSI (fully silicided gates) are expected to replace polysilicon in order to eliminate charge depletion in the gate conductor and provide new options for tuning the threshold voltage Vt. To keep increasing transistor drain currents that largely influence the switching speed of electronic circuits, it is necessary to enhance the flow of electric charges in the transistor channels. Charge mobility is a measure of the velocity of the electrons or holes in the MOS transistor channel.