Category Archives: TCAD

New Mobile App

DEVSIM LLC is pleased to announce the DEVSIM mobile app. The first of its kind, it is a TCAD semiconductor device simulator available for both Android and Apple devices. Its simulation engine is the DEVSIM open source TCAD simulator.

This release provides a 1 dimensional diode example, where you can experiment with different device parameters and visualize the results. Future versions will expand to include other textbook examples.

Quasi Fermi levels of 1D diode.

Get it on Google Play
Download on the App Store

Charon TCAD software open source release

The Charon simulator is now available under an open source software license:

This is an exciting development in the world of TCAD simulation, to have an open source TCAD simulator targeted toward large simulation problems.

From their website:

Charon is an open-source semiconductor device modeling code, widely referred to as a TCAD (technology computer-aided design) code, developed at Sandia National Laboratories. It is written in C++ and relies on another Sandia open-source project, Trilinos, for supporting code, such as nonlinear and linear solvers, finite-element and finite-volume libraries, I/O, etc. In addition to running on most Linux-based computers Charon also supports simulation of extremely large problems on massively parallel computing systems that support the MPI standard.

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.

SISPAD 2018 in Austin, TX

SISPAD 2018 will be September 24-26th in Austin, TX.

The SISPAD conference series provides an open forum for the presentation of the latest results and trends in process and device simulation. The conference is the leading forum for Technology Computer-Aided Design (TCAD) and is held alternatingly in the United States, Japan, and Europe in September.