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
- 3D Diffusion & Implantation
Victory Mesh:
- 3D Meshing
Victory Device:
- 3D Simulator
This demonstrates Monte Carlo implantation, diffusion, activation and oxidation of a silicon carbide (SiC) CoolMOS device. A CoolMOS device is a modification of a standard trench gate design, but with added superjunction features to reduce the trade-off between maximum breakdown voltage and low on-resistance.
As with all superjunction based devices, the device breakdown and on current (I_on) characteristics are very sensitive to achieving the optimum charge balance in the superjunction region of the device. The charge balance depends on the active dopant, not just the implanted doping levels, so care must be taken to ensure that the activation levels are correctly simulated. If the superjunction charge balance pinches off the channel at too low a drain voltage, a high breakdown voltage can be achieved, but the on-resistance will be too high. Conversely, if the channel pinches off at too high a drain voltage, a high on-current can be achieved, but the breakdown voltage will suffer severely.
A secondary effect in these devices that must be considered is channel punch-through. This effect can be confused with early “soft ” breakdown, as the effects are similar, but is not the result of impact ionization, but merely the reduction of internal barrier heights to the point where significant current flow occurs. An additional critical part of the optimization of this device is therefore the engineering of the exact location of the superjunction regions near the active drain metallurgical junction. If the p-doped pillars are placed too close to the channel at the drain end, the on-current will suffer significantly. If the p-doped pillars are too far away from the channel at the drain end, early onset punch-through similar to soft breakdown will occur.
In addition, to ensure near-constant gate control of the channel, and to reduce the trade-off introduced by the trench angle, the p-doped pillar adjacent to the active channel was tapered to match the angle of the trench etch, resulting in a near-constant p- channel depth.
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