Dual-Sided Power Semiconductor Layout to Suppress Turn-Off Filaments

The patent applies local quality by creating a modified control area (AMC) at the second side of the semiconductor body where the properties of control electrodes are locally altered. In this AMC, either no second control electrodes are provided or they are less effective in removing free charge carriers compared to areas outside the AMC. This localized modification prevents current filaments from forming in critical regions while maintaining effective control in other areas, thus resolving the contradiction between reliable switching behavior and prevention of harmful current filaments.

The patent implements local quality by spatially differentiating the effectiveness of second control electrodes across the semiconductor body. The modified control area (AMC) is defined where second control electrodes are either absent or less effective, while outside this area they maintain full effectiveness. This allows the device to achieve high switching performance in non-AMC regions while ensuring device robustness in AMC regions where current filament formation would be harmful, thus resolving the contradiction between switching performance and device robustness.

The patent resolves this contradiction by applying local quality through the modified control area (AMC) concept. In the AMC, the reduced or absent second control electrodes compensate for the less precise control inherent in planar electrode geometry. Outside the AMC, full control precision is maintained with conventional control electrode structures. This allows the use of simpler planar electrodes in critical areas where precision is less critical, while maintaining manufacturing simplicity overall without sacrificing necessary control precision in active regions.