3D comparison of DD_MS and NEGF_MS models for nanoscale FinFET

quantumex16.in : 3D comparison of DD_MS and NEGF_MS models for nanoscale FinFET

Requires: Device 3D/Quantum 3D
Minimum Versions: Atlas 5.28.1.R

This example demonstrates:

  • Comparison of quantum and classical transport models in 3D
  • Schrodinger-Poisson mesh
  • Fast product-space 2D SChrodinger solver
  • Quantum confinement in a FinFET channel

This example compares classical drift-diffusion (DD_MS) and quantum (NEGF_MS) transport models in a 6 by 7 nm thick Si FinFET with 30 nm gate length. Both solutions employ an uncoupled mode space approach, based on exactly the same Schrodinger and Poisson solvers and exactly the same material constants, thus allowing a one-to-one comparison.

A 2D Schrodinger solution in each slice of the device is obtained with a fast product-space 2D Schrodinger solver by specifying the SP.FAST parameter on the MODELS statement. Transport solution (drift diffusion or NEGF) is performed in all uncoupled subbands.

In order to decrease computational cost, we use a rough mesh in transport (X) direction for 3D Poisson equation. On top of this mesh, we specify a finer Schrodinger-Poisson mesh to decrease a discretization error in mode space drift-diffusion equations, and to avoid insufficient bandwidth of discretized transport Hamiltonian in NEGF equations. The S-P mesh is specified similar to the original Atlas mesh by statements SPX.MESH, SPY.MESH and SPZ.MESH. To lower interpolation error and interpolation time, it is a good idea to have the S-P mesh as similar as possible. Thus we keep SPY.MESH and SPZ.MESH the same as the original mesh and change only SPX.MESH. Note that due to the prismatic nature of the Atlas mesh, the SPZ.MESH statement is optional. If it is not specified, SPZ.MESH will be identical to the original mesh in the Z direction.

S-P mesh can be specified on top of the Atlas mesh to refine the quantum solution, but it becomes especially useful when an external non Atlas mesh is loaded and a rectangular mesh is required by the Schrodinger solver. A rectangular mesh is required by the 2D Schrodinger solver with the SP.FAST option and by 1D solvers in X and Y directions. A general 2D Schrodinger solver and 1D Schrodinger in Z direction can work on a triangular mesh in the X-Y plane.

To load and run this example, select the Load button in DeckBuild > Examples. This will copy the input file and any support files to your current working directory. Select the Run button in DeckBuild to execute the example.