Monolithically Integrated 4H-SiC MOSFET and JBS Diode (JBSFET) Using a Single Ohmic/Schottky Process Scheme

This letter reports a new 900 V 4H-SiC JBSFET containing an MOSFET with an integrated JBS diode in the center area of the chip. Both MOSFET and JBS diode structures utilize the same edge termination structure, which results in 30% reduction in SiC wafer area consumption in case of 10 A rating device. In order to form a Schottky contact for the JBS diode as well as ohmic contacts for n+ source and p+ body of the MOSFET, a simple metal process flow has been newly developed. It was found that Ni can simultaneously form ohmic contacts on n+ and p+ implanted regions while it remains a Schottky contact on the n-epitaxial drift layer when it is annealed at moderate temperature (900 degrees C for 2 min). The proposed JBSFET was successfully fabricated using a nine-mask on 6-in 4H-SiC wafers.