Multi-floating-zone JTE for 4.5 kV SiC power devices with exponentially modulated dimensions

Abstract

We propose a new multi-floating-zone junction-termination-extension (MFZ-JTE) using an exponentially modulated space and width for 4.5 kV SiC power devices to effectively spread out the electric field in reverse blocking mode and improve the tolerance against imprecise process control. A modified MFZ-JTE design with an exponential model was also proposed considering a stable patterning process. The blocking characteristics of the proposed MFZ-JTE using various exponential coefficients (alpha) in the model were evaluated for undesirable variations in the fabrication processes through TCAD simulations. The modified design for a 4.5 kV MFZ-JTE with alpha = 0.046 exhibited a low breakdown voltage deviation of 0.13% when the space variation ranged from -0.2 to +0.2 mu m and 0.14% when the variation in the surface charge density at the SiO2/SiC interface was within the range of 0 to -1 x 10(12) cm(-3).