3D Amorphous TFT simulation

tftex11.in : 3D Amorphous TFT simulation

Requires: Victory Process/Victory Mesh/Victory Device
Minimum Version Victory Process 7.30.4.R, Victory Mesh 1.4.6.R, Victory Device 1.14.1.R

By default Victory Process and Device run on just one processor. To ensure better perfomance on your computer the following simulation condition simflags="-P all" could be specidied in the go line starting Victory Process or Device. This means that all processors available will be used. If you want to use a smaller number of processors you can substitute "all" with a desired number, e.g. simflags="-P 4".

Although various design and physical effects have been successfully analyzed in 2D, it becomes important to start to analyze and predict device performance dependent on layout effect with 3D simulations. We will show in the following example here that a complete 3D process and device simulation solution is available to address future challenges in TFT design. Using SILVACO tools, designers can accelerate and optimize the development of for next generation display technologies.

This example demonstrates 3D A-Si:H TFT simulation using 3D process simulation Victory Cell and 3D device simulation Victory Device.

in order to create the 3D structure we used Victory Cell our 3D process simulator. Victory Cell is very suitable for 3D TFT devices simulation since it is layout driven, accurate, fast and easy to use. The 3D structure creation takes only few minutes. The particularity of the structure under test is that non 90 degree side-wall was used but 45 degree instead. After the process simulation is done a 3D structure is saved using a tetrahedron mesh to ensure that any shape created during 3D process simulation is well conserved and transferred to Victory Device for further device simulation.

Disordered materials contain a large number of defect states within the band gap of the material. To accurately model devices made of polycrystalline or amorphous materials, we need to take into account these defects. Victory Device can model interface states as well as defect states. Defect states is a combination of two exponentially decaying band tail states and two Gaussian distributions of mid-gap states. In addition to the defect models, band to band tunneling model was used to simulate accurately TFT devices in reverse. Device simulation were performed using 80 bits extended precision arithmetic to be sure to resolve accurately low current at low Vds. It is also very interesting to notice that due to the specific 3D effect the simulated IDVD curve when we reverse the source and the drain are different.

The e.field.derivs parameter causes Victory Device to consider the partial derivatives of the field-dependent band to band tunneling model with respect to the gradient of the potential. Including these derivatives slows down the computation and is usually not necessary, but in this case it helps the convergence.

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.