• TCAD Examples

    TCAD Examples

powerex24.in : Silicon Carbide (SiC) CoolMOS using Realistic Processing.

Requires: Victory Process - Victory Mesh - Victory Device Minimum Versions: Victory Process 7.76.1.R, Victory Mesh 1.9.0.R, Victory Device 1.20.0.R

In this example, we demonstrate realistic 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 super-junction features to reduce the compromise between maximum breakdown voltage and low on resistance.

As with all super-junction based devices, the device breakdown and on current (I_on) characteristics are very sensitive to achieving the optimum charge balance in the super-junction region of the device. Charge balance depends on the ACTIVE dopant, not just the implanted doping levels, so care has to be taken to ensure activation levels are correctly simulated. If the super-junction 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 taken into consideration, is channel punch through. This effect can be mistaken for early "soft" breakdown, since the effects are similar, but is not the result of impact ionization, merely the reduction of internal barrier heights, to the point where significant current flow occurs. An additional critical part of optimizing this device, was therefore engineering the exact location of the super-junction regions near the active drain metallurgic junction. If the p-doped pillars are located too close to the channel at the drain end, then on current suffers significantly. Place the p-doped pillars too far from the channel at the drain end and early onset punch-through occurs, which looks similar to a soft breakdown.

Also, to ensure near constant gate control of the channel, and to reduce the compromise arising from the angle of the trench, 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.

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.

Input Files
Output Results
These examples are for reference only. 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.
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