SiC Power Devices Vaibhav Ostwal 3-29-2017

Power Electronics Application and Desired Material Properties Ref. :IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 29, NO. 5, MAY 2014

WBG Materials Advantages of GaN and SiC among WBG: Matured technological processes Commercial availability of starting material i.e wafers and epitaxial layers GaN has better ON resistance Advantages of SiC over GaN: Higher thermal conductivity Availability of good quality bulk substrate (100-mm SiC wafers are in the market) Recent progress in Micro-pipe free material and screw & basal plane dislocations Ref.: IET Circuits Devices Syst., 2014, Vol. 8, Iss. 3, pp. 227–236

SiC Devices Progress Ref.: TIE.2017.2652401, IEEE Transactions on Industrial Electronics

SiC Power Rectifier Schottky Barrier Diode (SBD) junction barrier Schottky (JBS) diode P-I-N diode SBD and JBS Low turn-on voltage Turn-on voltage = 3V PIN diode High reverse biased current during ON to OFF transition high switching speed and low on-state losses lower blocking voltage and high leakage current Introducing p+ islands in this structure additionally shields the electric field from the Schottky contact thus reducing the leakage currents high-voltage operation and low leakage current reverse recovery charging during switching: Low speed Ref. :IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 29, NO. 5, MAY 2014

1200 V thinQ!™ SiC Diode Generation 5 design – Infineon Technologies Merged-Pin-Schottky (MPS) PIN MPS SBD Ref.: www.infineon.com

SiC P-I-N Diode: future smart grids and high-voltage power supplies Acceptor level of a carbon monovacancy was eliminated using thermal oxidation to enhance lifetime and achieve low differential on resistance Ref.: IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 62, NO. 2, FEBRUARY 2015

SiC Power Switching Devices Vertical SiC Devices SiC MOSFET Technology Operational voltage range: 600 V- 5 kV SiC IGBT Technology Over 5 kV voltage range SiC IGBT is more attractive DMOSFET (Double-implanted) UMOSFET Ref. :IEEE TRANSACTIONS ON POWER ELECTRONICS, VOL. 29, NO. 5, MAY 2014

UMOSFET ISSUE: Field Crowding at the trench corner Solution: P-trench implant Ref.: IEEE TRANSACTIONS ON ELECTRON DEVICES, VOL. 49, NO. 6, JUNE 2002 Using P-type trench implant ISSUE: Adding P+ trench implant creates RJFET

SiC Power Switch STEP TRENCH DEVICE Other progress in SiC MOSFETS: The highest blocking voltage of 15 kV was reported for SiC MOSFET (ref. : Proc. IEEE ECCE, 2014, pp. 449–454) Reliability of industry-leading 200°C-rated SiC MOSFET was reported by GE in 2014 (ref. : Proc. Int. Symp. Power Semicond. Devices ICs, 2014, pp. 297–300)

ROHM: 3rd Generation SiC MOSFET VGS-on = 18 V Ref.: http://www.rohm.co.jp

SiC Power Devices: Challenges Low electron mobility in the inversion channel layer: eliminate the SiC/SiO2 interface defects Gate oxide reliability with high temperature or high electric field Thermal management strategies: new package materials for high temperature application THANK YOU !