© 2018 Cree, Inc. All rights reserved© 2018 Cree, Inc. All rights reserved

Dave Grider, Edward Van Brunt , Shadi Sabri,Jim Richmond, Brett Hull, Scott Allen, and John W. PalmourWolfspeed, a Cree Company; Research Triangle Park, NC 27709dave.grider@wolfspeed.com

Medium Voltage SiC MOSFETJEDEC Reliability Qualification

13th Annual SiC MOS Workshop, UMD, Aug. 16-17, 2018

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Overcoming Adversity

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• Packaged parts tested• 3 lots / 25 parts each, no failures allowed• Typically at or near rated voltage levels, rated temperature, 1000hrs• Automotive qualification (AEC) successful for E-Series 900V MOSFET and 1200V Diode

JEDEC Qualification of Wolfspeed SiC Power Devices

• HOWEVER, lifetime prediction requires taking parts to failure• Use accelerated (field, temperature,…) conditions• Extrapolate to use conditions for lifetime prediction

HTGB HTGS ESDThermal

ShockH3TRB

Gate Mechanical StructureActive Structure,Passivation, Edge

HTRB

Stressed Device Component

JEDEC Qualification Tests

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4

• Completed on PowerAmerica-BP1/BP2 –Fabrication & JEDEC Qualification ofNew Design 3.3kV/50mOhm SiC MOSFETs and10kV/300mOhm SiC MOSFETs on 100 mm 4HN-SiC Wafers

‒ High Temperature Reverse Bias (HTRB)

‒ High Temperature Gate Bias (HTGB)

‒ Time Dependent Dielectric Breakdown (TDDB)

‒ Thermal Shock (TS)

‒ Body Diode Operating Lifetime (BDOL)

‒ Electrostatic Discharge (ESD)

‒ High Humidity High Temperature Reverse Bias (H3TRB)

• Underway on PowerAmerica-BP3 –Fabrication & JEDEC Qualification of6.5kV/100mOhm SiC MOSFETs on 150 mm 4HN-SiC Wafers

‒ High Temperature Reverse Bias (HTRB)

‒ High Temp Gate Bias (HTGB)

‒ Time Dependent Dielectric Breakdown (TDDB)

New Design 3.3kV/50m SiC MOSFET8.1mm

8.1

mm

New Design 10kV/300m SiC MOSFET

New Design 6.5kV/100m SiC MOSFET

8.1mm

8.1

mm

Medium Voltage SiC Power MOSFET JEDEC Qualification

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HTRB In-Situ Monitor:3.3kV/50mOhm SiC MOSFETs

No fails post 1000 Hr HTRB testFor 3.3kV/50mOhm SiC MOSFETs (3x25 Group)– Passed JEDEC HTRB Qualification Test

No fails post 1000 Hr HTRB testFor 10kV/300mOhm SiC MOSFET (3x25 Group)– Passed JEDEC HTRB Qualification Test

HTRB at 80% of Vrated , 175°C , 3 Fab Lots x 25* Devices/LotHTRB In-Situ Monitor:10kV/300mOhm SiC MOSFETs

Lot II had 20/20 passing devicesdue to lower packaging yield

Completed HTRB JEDEC Qualification Testing of3.3kV/50mOhm SiC MOSFETs and 10kV/300mOhm SiC MOSFETs

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No fails post 1000 Hr HTRB testFor 3.3kV/50mOhm SiC MOSFETs (3x25 Group)– Passed JEDEC HTRB Qualification Test

No fails post 1000 Hr HTRB testFor 10kV/300mOhm SiC MOSFET (3x25 Group)– Passed JEDEC HTRB Qualification Test

Lot II had 20/20 passing devicesdue to lower packaging yield

HTRB Post Measurement:3.3kV/50mOhm SiC MOSFETs

HTRB at 80% of Vrated , 175°C , 3 Fab Lots x 25* Devices/Lot

HTRB Post Measurement:10kV/300mOhm SiC MOSFETs

Completed HTRB JEDEC Qualification Testing of3.3kV/50mOhm SiC MOSFETs and 10kV/300mOhm SiC MOSFETs

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HTGB In-Situ Monitor:10 kV/300 mOhm SiC MOSFETs

HTGB In-Situ Monitor:3.3 kV/50 mOhm SiC MOSFETs

HTGB at Vgs-ated = 15V , 175°C , 3 Fab Lots x 25 Devices/Lot

No HTGB Failures in 1000 hrsFor 3.3kV/50mOhm SiC MOSFETs (3x25 Group)– Passed JEDEC HTGB Qualification Test

No HTGB Failures 1000 hrsFor 10kV/300mOhm SiC MOSFET (3x25 Group)- Passed JEDEC HTGB Qualification Test

Repeated at Vgs = +19V for both voltage classes with no failures

Completed HTGB JEDEC Qualification Testing of3.3kV/50mOhm SiC MOSFETs and 10kV/300mOhm SiC MOSFETs

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TDDB Life Projection:10 kV/300 mOhm SiC MOSFETs

TDDB Life Projection:3.3 kV/50 mOhm SiC MOSFETs

1e+4

1e+5

1e+6

1e+7

1e+8

1e+9

1e+10

1e+11

1e+12

1e+13

1e+14

1e+15

15 20 25 30 35 40 45 50

Gate Voltage (V)

10%, 50%, 90%Projected Failures

10%, 50%, 90%

Projected Failures

TDDB at 175°C , 1 Fab Lot x 30 Devices/Lot

Completed TDDB Gate Dielectric Testing of3.3kV/50mOhm SiC MOSFETs and 10kV/300mOhm SiC MOSFETs

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No Failures per JEDEC Standards for Visual Standards of Thermal Shock Test- For 3.3kV/50mOhm SiC MOSFETs (3x25 Group)- For10kV/300mOhm SiC MOSFETs (3x25 Group)

Thermal Shock (TS) Test at -55°C/175°C , 3 Fab Lots x 25 Devices/Lot

TS Pre/Post Die Images:3.3 kV/50 mOhm SiC MOSFETs

TS Pre/Post Die Images:10 kV/300 mOhm SiC MOSFETs

Completed Thermal Shock (TS) JEDEC Qualification Testing of3.3kV/50mOhm SiC MOSFETs and 10kV/300mOhm SiC MOSFETs

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SiC MOSFET Body Diode Operating Lifetime (BDOL) Test System

• 2 systems Have Been Assembled for the BDOL Test• Forced-Air Cooling with LED Power Supplies• Each BDOL Test System Configured for Either 3.3 kV (40 A) or 10 kV (15 A) Current Rating• BDOL Test System has In-Situ, Per-Die Drain Voltage and Temperature Monitoring

Completed Body Diode Operating Lifetime BDOL Qualification TestingOf 3.3kV/50mOhm SiC MOSFETs and 10kV/300mOhm SiC MOSFETs

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No BDOL Failures in 1000 hrsFor 3.3kV/50mOhm SiC MOSFETs

- No BDOL Failures in 1000 hrsFor 10kV/300mOhm SiC MOSFETs- Steps in Data Due to Changes in

Room Temperature, Notably at Startupof 3.3kV BDOL System at ~ 240 hrs

BDOL In-Situ Monitor:10kV/300mOhm SiC MOSFET BD @ 15A

BDOL In-Situ Monitor:3.3kV/50mOhm SiC MOSFET BD @ 40A

Completed Body Diode Operating Lifetime (BDOL) Qualification TestingOf 3.3kV/50mOhm SiC MOSFETs and 10kV/300mOhm SiC MOSFETs

BDOL Qual at Irated , 3 Fab Lots x 25* Devices/Lot

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• Threshold voltage shift

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• Completed ESD Testing of 3.3kV/50mOhm SiC MOSFETSAnd 10kV/300mOhm A SiC MOSFETs‒ HBM rated class 3B (8kV) – highest classification

‒ CDM rated Class IV (1kV) – highest classification

• Completed H3TRB Testing of 3.3kV/50mOhm SiC MOSFETSAnd 10kV/300mOhm SiC MOSFETs‒ No In-Situ Monitor for H3TRB Test System

‒ H3TRB Complete for 3.3kV/50mOhm SiC MOSFETs

‒ 72/75 pass all specs

‒ 3 failures noted with significant damage to die in-package

‒ H3TRB Complete for 10kV/300mOhm SiC MOSFETs, 75/75 parts passing

Completed ESD and H3TRB JEDEC Qualification TestingOf 3.3kV/50mOhm SiC MOSFETs and 10kV/300mOhm SiC MOSFETs

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• 8.1 x 8.1 mm 6.5kV/100mOhmSiC MOSFET Developed onONR SiC HEPS Program‒Over 2x Number of Die

Fabricated on 150 mm4HN-SiC Wafer

• 6.5kV/100mOhm SiCMOSFETs on 150mm 4HN-SiCWafers - Fabrication LotsUnderway In Preparation forHTRB, HTGB, and TDDBQualification

• Automated High VoltagePackage AssemblyModifications Completed Established XHV-8 Packagefor 3.3kV, 6.5kV, & 10kV SiCMOSFETs 6.5kV/100mOhm SiC MOSFET

6.5kV/100mOhm SiC MOSFETShot Map on

150 mm 4HN-SoC Wafer

6.5kV/100mOhm SiC MOSFETShot Map on 100 mm

4HN-SoC Wafer

6.5kV/100m SiC MOSFET Fabrication Underway on150mm 4HN-SiC Wafers for HTRB, HTGB, and TDDB JEDEC Qualification

© 2018 Cree, Inc. All rights reserved© 2018 Cree, Inc. All rights reserved

Questions?