Mobility of Carriers in Strong Inversion Layers Associated with Threshold Voltage for Gated Transistors

Area of Science:

• Semiconductor Physics
• Device Physics
• Materials Science

Background:

• The operation of n-channel Metal-Oxide-Semiconductor Field-Effect Transistors (NMOSFETs) relies on the formation of an n-type conductive channel through gate bias-induced inversion of a p-type substrate.
• Existing models for NMOSFETs require refinement to accurately capture device behavior across different operating regions and under various physical phenomena.

Purpose of the Study:

• To develop a more accurate theoretical framework for NMOSFETs by deriving and refining models for the inversion layer thickness and carrier behavior.
• To investigate the impact of phonon scattering and quantum confinement on device characteristics, particularly in the triode and saturation regions.

Main Methods:

• Derivation of inversion layer thickness using the concept of p (1/m^3) for planar MOSFETs, FinFETs, and IGBTs.
• Modification of conventional triode and saturation region formulas for improved fitting of characteristic curves.
• Inclusion of electromagnetic wave generation from accelerating carriers to model phonon scattering.
• Estimation of quantum confinement effects in potential quantum wells trapping carriers.

Main Results:

• Modified formulas provide better fitting of measured characteristic curves compared to conventional models.
• Incorporation of phonon scattering accurately explains Source-Drain current reduction near the triode-saturation transition.
• Quantum confinement effects are identified as crucial for understanding carrier trapping and mobility limitations.

Conclusions:

• The refined theoretical models, including phonon scattering and quantum confinement, offer a more comprehensive understanding of NMOSFET operation.
• These advancements enable more accurate prediction of device performance, crucial for designing next-generation semiconductor devices.