ECSEL 2014 RIA OSIRIS Ascatron AB
|Funding from Vinnova||SEK 1 933 992|
|Project duration||May 2015 - January 2019|
Purpose and goal
The project goal of OSIRIS was to grow SiC material using isotope enriched precursors to improve the performance of SiC power devices and GaN RF devices through improvements in thermal conductivity of the base material. SiC growth with isotope enriched precursors was successfully demonstrated and several wafers with thick layers were provided to the device partners Ascatron and III-V LAB. With these wafers 10kV SiC-PiN diodes, 1.2kV SiC Schottky diodes of JBS-type, and GaN RF devices were fabricated, evaluated, and perform as expected.
Expected results and effects
SiC PiN diodes blocking 14kV and SiC Schottky diodes blocking 1.4kV were demonstrated by Ascatron using OSIRIS wafer material. The electrical device performance was similar to devices based on commercially available wafers. Thermal measurements showed a bit lower temperature on the surface of the devices made on OSIRIS material, in accordance to simulation results. The difference is however too small to have any decisive influence on the performance at normal operation since the main part of thermal resistance originates from packaging of the SiC chip.
Planned approach and implementation
Ascatron fabricated 10kV SiC PiN diodes and 1.2kV Schottky diodes using wafers grown by the OSIRIS material partners Norstel and Linköping University. The wafer fabrication for the second batch of PiN diodes got delayed due to the availability of isotope enriched precursors. This affected the device wafer fabrication, which will be finished after the project end, and used in a MISTRA financed project with GE. The manufacturing of devices for evaluation of the SiC material developed in the Project also lead to improvement of Ascatron own process technology for very high voltage devices.