Proven Power Cycling Reliability of Ohmic Annealing Free SiC Power Device through the Use of SmartSiC^TM Substrate

Abstract

The Smart CutTM technology enables the combination of a high quality single crystal SiC layer onto a low resistivity handle wafer (<5mOhm.cm), allowing device optimization as well as the reduction of device’s conduction and switching losses. On this new SmartSiCTM substrate, the sheet resistance of the back side contact after metal deposition, without anneal, is about 10x lower than the annealed back side contact on 4H-SiC. Schottky-barrier vertical structures thinned down to 250μm were prepared for power cycling tests (PCT) measurements. Up to 250 k cycles, the devices remained within the specifications of AQG324 for samples prepared from SmartSiCTM substrates. We are demonstrating here that in addition to a higher current rating (up to 20%), the SmartSiCTM substrate enables a device fabrication simplification by skipping the annealing of the back-side ohmic contact, without compromising either the back-side contact resistance or the assembly PCsec reliability.