Every software package contains a full set of examples suitable for that version and are installed with the software. If you see examples here that are not in your installation you should consider updating to a later version of the software. These examples can be used by beginners and advanced users for product evaluation, teaching purposes, and self-training.
Required Modules
Victory Process
- 2D Diffusion & Implantation
- 2D Oxidation
Victory Mesh
- 2D Remeshing
Victory Device
- 2D Simulator
This example demonstrates 2D process simulation and basic device tests for a U-shaped trench MOSFET or UMOS.
UMOS device belongs to family of the vertical MOSFET devices which differ from standard (horizontal) MOSFETs in that the gate is “vertical ” and the drain is on the bottom of the device. In UMOS, the vertical gate is formed by etching and oxidizing of a deep trench in the silicon. The device uses two connections to the source, resulting in a much larger area through which the current can flow. This reduces the on-resistance of the device, allowing to handle higher power than standard MOSFETs. The vertical nature of the UMOS structure allows good device characteristics to be achieved with a smaller “layout footprint ” than conventional power MOSFETs.
Since UMOS is a symmetrical device, only half of the structure is simulated in Victory Process. The full structure is later created using the MIRROR feature in Victory Mesh.
The key process step, trench formation, is simulated by combining two etch models:
Geometrical angled DRY etching
Geometrical WET etching with the curvature of the trench bottom
This deck takes advantage of Victory Process’ ability to adjust the volume mesh for specific IMPLANT/DIFFUSION steps. It starts with a very coarse volume mesh which allow to speed up the EPITAXY and trench formation steps. Then, additional volume mesh lines are placed in important areas around the trench as well as in the implanted areas by using the LINE statements. Also, the fine mesh initially required to capture a sharp peak of the n+ arsenic implant is later coarsened by using the LINE REMOVE feature of Victory Process.
In this example, the default analytical model is used for all implant steps to reduce simulation time. The Monte Carlo implant model is recommended for most real device simulations.
Several parameters of the device structure are extracted along the way and can be used for process optimization.
After process simulation, the full structure is prepared for device simulation using Victory Mesh. First, the final state of Victory process simulation is LOADed, then the structure is MIRRORed, and REMESHed and REFINEd using the Delaunay mesh. The finest refinement is performed along the gate to obtain reproducible Vth. The mesh is also refined at other interfaces and along the PN junction for accurate breakdown voltage simulation.
Finally, Victory Device is used to extract two basic device characteristics:
Threshold voltage Vth
Breakdown voltage BV.
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