Abstract
An investigation into the increased leakage currents and reduced blocking voltages associated with 1450°C lifetime enhancement oxidation for the 4H-SiC p-GTOs is presented. Roughening of the 4H-SiC surface due to localized crystallization of SiO2, or crystobalite formation, during the high temperature oxidation was identified as one of the main causes of this issue. A factor of 30 difference in permeability to O2 between amorphous SiO2 and crystobalite caused uneven oxidation, which resulted in significant roughness. This roughness, placed at the metallurgical junction between the gate and the drift layer, where the E-field is greatest, is believed to be responsible for the premature breakdown characteristics. A 2-step lifetime enhancement process, which moves this roughness to the lower E-field region of the device was introduced to alleviate this issue. A 15 kV 4H-SiC p-GTO with the 2-step lifetime enhancement process demonstrated a significant reduction in VF over the 1300°C oxidized devices, without any impact on blocking characteristics.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
