Expanding the dose window of step-etched space-modulated JTE for ultrahigh voltage 4H-SiC devices

Abstract

A step-etched space-modulated junction termination extension (SE-SM-JTE) is proposed for ultrahigh voltage (≥10 kV) 4H-SiC devices in this work. The proposed structure creates a stepped effective JTE dose profile by introducing the step etching into space-modulated JTE (SM-JTE), which shows great merits in the compromises of the JTE dose window, termination efficiency, termination area, and the complexity of the fabrication process. According to the TCAD simulation results, the SE-SM-JTE with a length of 300 μm (3 times the drift layer thickness) obtains a wide implantation dose window of ±47 % above 12 kV, achieving a wide tolerance to JTE dose and surface fixed charge. The maximum breakdown voltage (BV) of the proposed SE-SM-JTE is 13.8 kV, exhibiting a termination efficiency of 92 %. Moreover, the proposed JTE structure requires only a single ion implantation and subsequent two etchings, which facilitates the fabrication feasibility in ultrahigh voltage 4H-SiC devices.