Grain Boundary Generation : Grain Boundary Generation

Requires: Victory Mesh/Victory Device
Minimum Versions: Victory Mesh 1.4.7.R / Victory Device 1.14.1.R
Laser Annealing processes, such as Excimer Laser Annealing (ELA) are used to convert amorphous silicon to polycrystalline silicon and enhance carrier mobility. The poly-Si structure (grain boundary) is dependant on the laser wavelength, pulse width and spatial beam.
Victory Mesh can emulate grain boundaries formation using a Voronoi discretization. This example will show how a region of a 3D structure can be converted to a polycrystalline region (it is also possible to create 2D grains and save into a layout file for use with the process simulator; Victory Process). This example extends beyond the work published in the Simulation Standard article: 3D TFT Simulation of Grains and Grain Boundaries, Vol 29, No. 1 Jan-Mar 2019. Here the grain sizes are varied in all directions.
The example begins by generating a simple layered TFT device using the layers command. The grain command is then used to convert the polysilicon region into polycrystalline silicon. The grain size, spacing and standard deviation can all be chosen, via the size, delta and sigma parameters respectively.
The final structure is then remeshed and refined. It can be seen that this device has fully 3D grain profile (something not possible using the layout driven approach). Following the definition of the electrodes the device can be imported into Victory Device.
Forward and reverse bias transfer characteristics of the device with the polycrystalline silicon region are performed in the Victory Device simulation.