Influence of High-k Material in Gate Engineering and in Multi-Gate Field Effect Transistor Devices

Abstract

Complementary metal oxide semiconductor technology was introduced to increase mass production of metal oxide semiconductor field effect transistors (MOSFET). Initially in the chapter, we introduce the device structure of double-gate (DG) MOSFET and gate-all-around (GAA) MOSFET. The double-gate control of MOSFET is used to force whole silicon film in strong inversion or strong accumulation. GAA MOSFET has excellent electrostatic control over the device. Downscaling of double-gate and GAA MOSFET devices increases short channel effects, leakage current, and lower sub-threshold swing and reduces the ON-state current. Thus, to improve ON-state current and reduce short channel effects, gate engineering for devices is proposed. The chapter is further continued with gate engineering using double material and triple material for the gate. Similar to double material, in triple material gate engineering, three metals with different work functions are used as gate. The use of three metals further improves electrostatic characteristics of device. The gate engineering devices include dual-material (DM) DG MOSFET, triple-material (TM) DG MOSFET, dual-material (DM) GAA MOSFET, and triple-material (TM) GAA MOSFET. Further we move on to high-k dielectric stacked along with gate engineering of multi-gate MOSFET devices. The high-k stacked multi-gate devices include double-gate MOSFET, double-metal DG MOSFET, triple-metal DG MOSFET, GAA MOSFET, double-metal GAA MOSFET, and triple-metal GAA MOSFET.