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.
Improvement of RHIC warm beam vacuum for high intensity operation
With increasing ion beam intensity during recent RHIC operations, pressure rises of several decades were observed at a few warm vacuum sections. Improvement of the warm sections has been carried out in last year's shutdown. Extensive in-situ bakes, additional UHV pumping, electron detectors and beam tube solenoids have been implemented. Vacuum monitoring and interlock were enhanced to reduce premature beam aborts. The effectiveness of these measures in reducing the beam induced pressure bumps and in increasing the vacuum system reliability are discussed and summarized.