Category Archives: DEVSIM

DEVSIM 1.4.0 Release


DEVSIM 1.4.0 is now available for download.  Please visit for more information about the software.  Documentation is available from  Binary releases are available from:

The devsim.custom_equation() and devsim.register_function() commands take Python functions, instead of the a string with the function name.

The following commands are available to store data on edges and element edges:

  • edge_solution()
  • set_edge_values()
  • element_solution()
  • set_element_values()

DEVSIM 1.3.0 Release


DEVSIM 1.3.0 is now available for download.  Please visit for more information about the software.  Documentation is availabe from  Binary releases are available from:

Python 3 Examples

All of the Tcl regression tests in the testing directory have been converted to Python 3. These tests serve as examples for features that were previously only tested using Tcl scripting.

Tcl Support Deprecated

Tcl support is deprecated and will be removed in a future release of the software.

Binary Releases

Scripting Languages

Python 3 is now the only scripting language in the releases available from:

Math Library

The Microsoft Windows version now uses Intel MKL Pardiso for direct matrix factorization. Both Linux and Apple macOS have been using Intel MKL Pardiso since November 1, 2015. Binary releases for all operating systems use BLAS/LAPACK routines from Intel Math Kernel Library.

DEVSIM 1.2.0 Release

DEVSIM releases now have better support for Python 3. Using the stable ABI, the software is able to run with newer Python 3 releases, without rebuilding the software.

Support for Python 2.7 has been removed.

The banner has been removed when the DEVSIM module is imported.

The symdiff python module is now part of the DEVSIM release. This module has additional features not available using the devsim.symdiff command from DEVSIM.

Please visit for information about downloading this software and its documentation. SYMDIFF is available from

DEVSIM 1.1.0 Release

With this version, the evaluation of the Bernoulli function and its derivative is improved. Users should expect changes in numerical results. Please visit for information about downloading this software and its documentation.

The Bernoulli function,

\textrm{B} \left( x \right) = \frac{x}{\mathrm{e}^x – 1}

and its derivative,

\textrm{dBdx} \left( x \right) = \frac{\mathrm{e}^x – 1 – x \mathrm{e}^x}{\left(\mathrm{e}^x – 1\right)^2}

have been refactored. They are used to calculate electron and hole current densities using the Scharfetter-Gummel method.

The Bernoulli function has numerical issues when x approaches 0 and requires special evaluation. In this release, DEVSIM takes advantage of C++ math library functions for evaluating the denominator.

In addition, these functions are evaluated with extended precision, when this mode is enabled in the simulator.

Users should expect that simulation results should change in the number of solver iterations and small differences in simulation results.

DEVSIM 1.0.0 Release

New release of the DEVSIM® Semiconductor Device Simulator

December 18, 2018: DEVSIM LLC announces the release of version 1.0 of the DEVSIM® TCAD Semiconductor Device Simulator. Open source since 2013, DEVSIM® uses finite volume methods to solve for the electrical behavior of semiconductor devices on a mesh. In addition to the standard drift-diffusion equations, the density-gradient method can be used to account for quantum effects near semiconductor insulator boundaries. This approach is suitable for:

  • Simulating Advanced Semiconductor Devices
  • Capacitance Extraction
  • Generalized PDE Simulation

In this release, the software has been extended to support easier integration into existing Python installations on macOS, Microsoft Windows, and Linux operating systems. In addition, the version numbering system has been adapted to reflect major and minor changes to the software.

DEVSIM® is available from The site include more information for those who wish to use or participate in development of this software.


DEVSIM LLC was founded in 2008 to provide TCAD simulation software and programming services. For more information, please visit

DEVSIM® is a registered trademark of DEVSIM LLC. All product names, trademarks and registered trademarks are property of their respective owners.

Density Gradient Method

The Density Gradient Method has been implemented as a simulation example for DEVSIM. This method is a quantum mechanical correction for carrier densities near a semiconductor/insulator interface.

The example scripts simulate both a 1D and 2D MOSCAP structure. The scripts generate plots to visualize the results.

It can be downloaded from

Semiconductor Device Simulation Using DEVSIM

Semiconductor Device Simulation Using DEVSIM is now available from our site.

DEVSIM is a technology computer aided design (TCAD) simulation software. It is released under an open source license. The software solves user defined partial differential equations (PDEs) on 1D, 2D, and 3D meshes. It is implemented in C++ using custom code and a collection of open source libraries. The Python scripting interface enables users to setup and control their simulations.

In this chapter, we present an overview of the tool. This is followed with a bipolar junction transistor (BJT) design and characterization example. A collection of open source tools were used to create a simulation mesh, and visualize results

The Python scripts for simulation are here:

DEVSIM under new open source license

The DEVSIM source code is now released under the Apache License, Version 2.0. It was previously under the LGPL 3.0. The license change is intended to promote adoption of the software and attract new contributors. A brief synopsis of the license is here.

The spirit of the Apache License is also more in line with the license terms packages that DEVSIM relies upon. More information about DEVSIM is available from