‘LAST POWER’, the EU program to develop reliable and economical power
electronics, recently reported on the project’s achievements. The project was launched in
2010 through the European Nanoelectronics Initiative Advisory Council (ENIAC)
Joint Undertaking (JU), which links private companies, universities and public
research centers to study of wide bandgap semiconductors (SiC and GaN). ‘LAST POWER’ is an acronym for ‘Large Area silicon carbide Substrates and heTeroepitaxial GaN for POWER device applications’.
The main achievements stemmed from SiCrystal’s development of 150mm
diameter substrates with a cut-off angle of 2°-off axis with comparable quality
to the 100mm 4°-off material available at the project’s beginning. At
LPE/ETC, a novel CVD (Chemical Vapor Deposition) reactor was employed to
fabricate 600-1200V JBS (Junction Barrier Schottky) diodes and MOSFETs on 150mm
4H-SiC. The JBS diodes on 150 mm substrates had electrical performance
comparable with the state-of-the-art 4°-off material. Chemical mechanical
polishing (CMP) process, StepSiC ® reclamation and planarization from NOVASiC, enabled the JBS fabrication. The same company also developed epitaxial growth process for fabricating both MOSFET and JFET devices.
Acreo and FORTH with the support of CCR, jointly developed novel modules for
high-temperature 4H-SiC JFETs and MOSFETs. CCR studied molding compounds and
“lead-free” die-attach materials for reliable packaging.
ST Microelectronics also successfully produced AlGaN/GaN HEMTs epitaxial
structures with a 3 μm thickness and 200V breakdown. Last Power collaborated
with IMM-CNR, Unipress, and ST to develop ‘gold free’ production
for normally-off AlGaN/GaN HEMTs that is fully compatible with the fabrication
process at the ST production line.