Equivalent Oxide Thickness of Trigate SOI MOSFETs With High-κ Insulators

The evolution of traditional metal–oxide–semiconductor field-effect transistors (MOSFETs) from planar single-gate devices into 3-D ones with multiple gates and high-κinsulators imposes the use of new electrical models that accurately reproduce their behavior. This paper demonstrates that the typical expression of equivalent oxide thickness (EOT) for planar devices with high-κgate insulators becomes useless for nonplanar ones such as triple-gate (trigate) silicon-on-insulator MOSFETs. An alternative expression of the EOT for these trigate devices has been developed through a semianalytical approach to the gate-insulator capacitance. The proposed model correctly reproduces the total electron density in a wide range of device dimensions and applied biases.