Patrick Shea
University of Central Florida
Subject Listing - Engineering
Advisor: Dr. Z. John Shen
Friday, Oral Session 4, Presentation 3, Health & Fitness Center 203
MODELING AND SIMULATION OF EDGE TERMINATION IN SUPERJUNCTION SEMICONDUCTOR DEVICES
Superjunction power semiconductor devices are a new type of high voltage switches used in power electronic systems. The term "superjunction" refers to a PN junction structure made of alternating P and N columns. When compared to conventional 1-D PN structures, the superjunction allows higher drift region doping for a given breakdown voltage, which can translate into a 5X reduction in on-resistance. This improvement in the trade-off between on-resistance and breakdown voltage offers significant opportunity for the development of high-efficiency power semiconductor devices.
Edge termination consumes significant wafer area, but is required to provide maximum breakdown voltage. The scientific community has little published literature on the design methodology of edge termination for superjunction devices. The objective of this research is to design a termination structure for superjunction devices that is compatible with an innovative MEMS fabrication technology, offering breakdown voltages as close as possible to ideal and allowing reasonable fabrication costs and efficient use of wafer area.
This research utilizes ISE TCAD software to design radically different termination structures for a superjunction diode with ideal breakdown voltage of 740 Volts. The software simulates the behavior of each structure during avalanche breakdown. The resulting data is used to obtain an IV characteristic plot and observe properties such as electric field distribution. Simulations show a breakdown voltage of 84% of ideal for a manufacturable structure with a termination width of only 55 microns. This particular design consists of a refilled trench which is partially covered by a terminal extension (field plate). The doping profile, dimensions, and refill material of this design are being optimized.
This research has taken an innovative approach to semiconductor device simulation and has revealed interesting data regarding the physical behavior of superjunction semiconductor devices.
Advisor: Dr. Z. John Shen, Associate Professor, Department of Electrical and Computer Engineering, University of Central Florida, Orlando, FL