Gate coupling and charge distribution in nanowire field effect transistors

Area of Science:

• Semiconductor physics
• Nanotechnology
• Materials science

Background:

• Traditional models of nanowire field-effect transistors (FETs) often assume infinite device length and ideal metallic dielectric properties.
• These assumptions simplify analysis but may not accurately reflect real-world device behavior and charge distribution.

Purpose of the Study:

• To investigate the influence of gate oxide geometry, nanowire semiconductivity, and finite device length on charge distribution in nanowire FETs.
• To provide numerical correction factors for existing analytical models and calculations used in nanowire FET characterization.

Main Methods:

• Numerical solution of the three-dimensional Poisson's equation.
• Modeling of field and space charge distributions in back-gate and top-gate nanowire FET configurations.

Main Results:

• Nanowire geometry, semiconductivity, and finite length significantly alter induced charge amount and spatial distribution.
• Deviations from idealized models are substantial, highlighting the importance of considering these factors.
• Numerical correction factors were derived to improve the accuracy of capacitance formulas and transport calculations.

Conclusions:

• The commonly accepted simplified models for nanowire FETs are insufficient for accurate charge distribution and carrier transport analysis.
• Accurate modeling requires incorporating realistic parameters such as gate oxide geometry, nanowire semiconductivity, and finite device length.
• The developed correction factors enhance the predictive power of models used in nanowire FET research and development.