# Introduction¶

DEVSIM is semiconductor device simulation software which uses the finite volume method. It solves partial differential equations on a mesh. The Python interface allows users to specify their own equations.

## Software Features¶

• Documentation

• Python and Tcl scripting

• DC, small-signal AC, impedance field method, transient

• User specified partial differential equations (PDE).

• 1D, 2D, and 3D simulation

• 1D, 2D mesher

• Import 3D meshes.

• 2D cylindrical coordinate simulation

• ASCII file format with PDE embedded.

## Supported Platforms¶

• macOS 10.13

• Microsoft Windows

• Red Hat 7 (Centos Compatible)

DEVSIM is a registered trademark of DEVSIM LLC.

• Binaries

• Source Code

# Examples¶

In addition to the examples provided with the distribution, and listed in the documentation. The following examples are also available:

# Documentation¶

## Publications¶

### Project¶

• DEVSIM: A TCAD Semiconductor Device Simulator

Sanchez, J. E., “DEVSIM: A TCAD Semiconductor Device Simulator,” Journal of Open Source Software, 2022, doi: 10.21105/joss.03898.

• Element Edge Based Discretization for TCAD Device Simulation

J. E. Sanchez, and Q. Chen, “Element Edge Based Discretization for TCAD Device Simulation,” IEEE Transactions on Electron Devices, 2021, doi: 10.1109/TED.2021.3094776.

Preprint available from TechRxiv, doi: 10.36227/techrxiv.14129081.

### Using the Simulator¶

• Analytical model for donor like Gaussian traps in organic thin-film transistor

Q. Chen, J. E. Sanchez, D. Lin, Y. Lei, G. Zhu, “Analytical model for donor like Gaussian traps in organic thin-film transistor,” Organic Electronics, 2022 doi: 10.1016/j.orgel.2022.106464.

• Technology computer aided design based deep level transient spectra: Simulation of high-purity germanium crystals

J. Lauwaert, “Technology computer aided design based deep level transient spectra: Simulation of high-purity germanium crystals,” Journal of Physics D: Applied Physics, 2021, doi: 10.1088/1361-6463/ac34ad.

• The Impact of Contact Position on the Retention Performance in Thin-Film Ferroelectric Transistors

Q. Chen, D. Lin, Q. Wang, J. Yang, J. E. Sanchez, and G. Zhu, “The Impact of Contact Position on the Retention Performance in Thin-Film Ferroelectric Transistors,” Physica Status Solidi A 2100408, 2021, doi: 10.1002/pssa.202100408.

• Designing a Simulator for an Electrically-Pumped Organic Laser Diode

L. Hulbert, “Designing a Simulator for an Electrically-Pumped Organic Laser Diode,” Master’s Thesis, California Polytechnic State University, San Luis Obispo, CA, 2019, doi: 10.15368/theses.2019.60.

# Model Example¶

Solving the Poisson equation in a dielectric is:

$$\epsilon \int \nabla \psi \cdot \partial r = 0$$

which is equivalent to solving

$$\epsilon \int \vec{E} \cdot \partial \vec{s} = 0$$

In DEVSIM, the surface integral is performed by specifying an equation in the region with an edge model which is the negative gradient of the potential, $$\psi$$. An example implementation is located in 1

def CreateOxidePotentialOnly(device, region, update_type="default"):
'''
Create electric field model in oxide
Creates Potential solution variable if not available
'''
if not InNodeModelList(device, region, "Potential"):
print "Creating Node Solution Potential"
CreateSolution(device, region, "Potential")

efield="(Potential@n0 - Potential@n1)*EdgeInverseLength"
# this needs to remove derivatives w.r.t. independents
CreateEdgeModel(device, region, "ElectricField", efield)
CreateEdgeModelDerivatives(device, region, "ElectricField", efield, "Potential")
dfield="Permittivity*ElectricField"
CreateEdgeModel(device, region, "PotentialEdgeFlux", dfield)
CreateEdgeModelDerivatives(device, region, "PotentialEdgeFlux", dfield, "Potential")
equation(device=device, region=region, name="PotentialEquation", variable_name="Potential",
edge_model="PotentialEdgeFlux", variable_update=update_type)