Study of the packaging effect on blocking voltage of power devices during durability test
We investigated why the blocking voltages of a power device are lowered during a durability test through a device simulation called Technology Computer Aided Design (TCAD) and measurements using the optical beam induced current (OBIC) method. We found that the spread of the depletion layer caused by the bonding wire is what decreased the blocking voltage.
An Improved Methodology for the CAD Optimization of Multiple Floating Field-Limiting Ring Terminations
We derive an efficient and accurate computer-aided-design-based design methodology for the optimization of floating field-limiting ring terminations. The proposed approach is based on an iterative optimization of the ring-to-ring spacings starting from the outermost ring and proceeding back toward the main junction. Physics-based simulations show that each optimization step does not impair the previous one, thus allowing to easily identify the minimum number of rings needed to achieve the desired termination efficiency yet minimizing the number of simulation steps. The accuracy of the method is thoroughly discussed on the basis of comparisons against either literature results or experimental data.
Planar terminations in 4H-SiC Schottky diodes with low leakage and high yields
Various planar termination techniques were analyzed that extend the maximum blocking voltage in SIC devices while giving low leakage currents and high yields. Among various techniques analyzed, it was found that: guard ring termination is more effective than unterminated; field plate termination is more effective than guard ring termination; and field plate, double implanted field rings, single and double trench rings are similar in their effectiveness in the 500-800 V range. Single implanted field rings gave the highest average breakdown voltage as well as the highest voltage (805 V) device. While the yield among all devices was 22%, the yield among the ones with only a single implanted floating field ring was 67%.