Every software package contains a full set of examples suitable for that version and are installed with the software. If you see examples here that are not in your installation you should consider updating to a later version of the software. These examples can be used by beginners and advanced users for product evaluation, teaching purposes, and self-training.

Required Modules

Victory Atomistic

How to compute the 3D carrier density and effective masses of a FinFET.

This example shows how to use the Poisson-Schrödinger (PS) solver to compute the 3D carrier density profile of a Si FinFET and the extraction of the effective masses from the first sub-bands of its electronic band structure.

The simulated device is a Si FinFET slice, with a trapezoidal cross section with a height = 33 nm, bottom length = 12 nm, and top length = 8 nm. The FinFET has a tri-gate oxide of 1nm thickness and channel oriented along the <110> direction. Si is lightly N-doped and described in tight binding with a sp3d5s* basis.

A voltage ramp is applied to the gate: for each voltage point Vg the PS loop is called up to reach

self-consistency. The total charge function Qinv(Vg) is written in the standard output file.

The band structure and 3D carrier density are visualized with Victory Visual.
The effective mass is extracted from the band curvature. In this example, the effective masses of the first 2 sub-bands are automatically calculated in the following file:

>cat CB_bands_effective_masses.dat

Band Number Valley Number Direction Kposition/pi Effective Mass Energy
1 |1 |<1,0,0> |[0,0,0] |0.1988858 |1.14683
1 |2 |<1,0,0> |[-2.130517,-0,-0] |0.5464755 |1.143986
1 |3 |<1,0,0> |[2.130517,0,0] |0.5464756 |1.143986
2 |1 |<1,0,0> |[0,0,0] |0.1988125 |1.146898
2 |2 |<1,0,0> |[-2.130517,-0,-0] |0.5460794 |1.143993
2 |3 |<1,0,0> |[2.130517,0,0] |0.5460793 |1.143993

The total charge can be extracted from the standard ouput for each Vg of the voltage ramp.

Two possibilities to save the runtime standard output:

– run deckbuild command using ‘-out vaex02.out’ option or

– under Deckduild in the output panel, do a right click “Save Runtime… ” and save the runtime output.

Here is a simple Unix command to extract the charge from stdout for each Vg when the self-consistency is reached:

>grep charge vaex02.out | awk ‘BEGIN {i = 0};/#[1-9]/{flag=1;next}/#[1-9]/{flag=0}flag {print “Vg_ “i++ ” “$3}; END {print “Vg_ “i++ ” “$3}’

Vg_0 -4.26639141e-03
Vg_1 -7.67585604e-02
Vg_2 -2.77907688e-01
Vg_3 -5.43982488e-01
Vg_4 -6.91155904e-01
Vg_5 -8.44715377e-01
Vg_6 -1.00397938e+00
Vg_7 -1.16810858e+00
Vg_8 -1.33647352e+00
Vg_9 -1.50854420e+00
Vg_10 -1.68388756e+00
Vg_11 -1.86212190e+00

This data is useful to analyse the modulation of threshold voltage due to the quantum confinement in the fin width in the nanometre regime.

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