341
Compact Models for Ultrathin Body FETs
9.6 Summary
This chapter presented an overview of the present state-of-the-art surface
potential–based compact models of thin-body CMG and IMG FET devices
for circuit CAD. Each device model consists of a core model for large devices
and real device submodels to analyze the physical and geometrical effects on
these devices. The basic features of the model include capturing the important physics of thin-body multigate transistors such as the volume inversion and the dynamic V th shift for body bias in ultrathin body transistors.
The models are valid for digital as well as analog circuit analysis with the
C–V models that simulate the transcapacitances. This chapter is intended to
provide readers the present state-of-the-art modeling activities in thin-body
FET devices. The detailed models and modeling methodologies including
updates can be found in the literature [74].
Exercises
9.1 Complete the mathematical steps following the procedure described
in Chapter 3 to derive Equation 9.13 for channel potential f 1 (x, y) at any
point (x, y) in the channel of a typical symmetric DG-MOSFET device.
9.2 Complete the mathematical steps following the procedure described
in Chapter 3 to derive Equation 9.17 for channel potential f 2 (x, y) at
any point (x, y) in the channel of a typical symmetric DG-MOSFET
device.
9.3 Use Equations from exercises 9.1 and 9.2 to derive:
a. Vertical electrical field at any point y along the channel of the
symmetric DG-MOSFET device
b. Gate voltage for a fully depleted symmetrical DG-MOSFET
structure
9.4 What is the volume inversion in DG-MOSFETs? Describe the effect
of volume inversion on DG-MOSFET device performance.
9.5 Describe the difference between the electrical and structural
Quantum Mechanical effects in DG-MOSFETs; qualitatively plot the
centroid of inversion charge as a function of body thickness. Explain
your results.
Compact Models for Ultrathin Body FETs
9.6 Summary
This chapter presented an overview of the present state-of-the-art surface
potential–based compact models of thin-body CMG and IMG FET devices
for circuit CAD. Each device model consists of a core model for large devices
and real device submodels to analyze the physical and geometrical effects on
these devices. The basic features of the model include capturing the important physics of thin-body multigate transistors such as the volume inversion and the dynamic V th shift for body bias in ultrathin body transistors.
The models are valid for digital as well as analog circuit analysis with the
C–V models that simulate the transcapacitances. This chapter is intended to
provide readers the present state-of-the-art modeling activities in thin-body
FET devices. The detailed models and modeling methodologies including
updates can be found in the literature [74].
Exercises
9.1 Complete the mathematical steps following the procedure described
in Chapter 3 to derive Equation 9.13 for channel potential f 1 (x, y) at any
point (x, y) in the channel of a typical symmetric DG-MOSFET device.
9.2 Complete the mathematical steps following the procedure described
in Chapter 3 to derive Equation 9.17 for channel potential f 2 (x, y) at
any point (x, y) in the channel of a typical symmetric DG-MOSFET
device.
9.3 Use Equations from exercises 9.1 and 9.2 to derive:
a. Vertical electrical field at any point y along the channel of the
symmetric DG-MOSFET device
b. Gate voltage for a fully depleted symmetrical DG-MOSFET
structure
9.4 What is the volume inversion in DG-MOSFETs? Describe the effect
of volume inversion on DG-MOSFET device performance.
9.5 Describe the difference between the electrical and structural
Quantum Mechanical effects in DG-MOSFETs; qualitatively plot the
centroid of inversion charge as a function of body thickness. Explain
your results.