Technology, Device and Application CoolSiC SiC MOSFET TM

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CoolSiC ^TM SiC MOSFET

Technology, Device and Application

Kwokwai Ma

Infineon Technologies Hong Kong Ltd

Revolution to rely on.

Copyright © Infineon Technologies AG 2016. All rights reserved.

Abstract

l Silicon Carbide (SiC) had excellent material properties as the base material for next generation of power semiconductor. In developing SiC MOSFET, gate oxide reliability issues had to be first overcome before commercial application. Besides, a high and stable gate-source voltage threshold V

GS(th)

is also an important parameter for operation robustness. SiC MOSFET with such characteristics can directly use existing high-speed IGBT gate driver IC's.

l The linear voltage drop characteristics of SiC MOSFET will bring lower conduction loss averaged over full AC cycle compared to similarly rate IGBT.

Lower switching loss enable higher switching frequency. Using package with auxiliary source terminal for gate driving will further reduce switching losses. Dynamic characteristics can fully controlled by simple gate resistors.

l The low switching losses characteristics of SiC MOSFET can substantially reduce power losses in high switching frequency operation. Significant power loss reduction is also possible even at low switching frequency and low switching speed. in T-type 3-level topology, SiC MOSFET solution enable three times higher switching freqeuncy at same efficiency.

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Topics

l Technology

l Device characteristics l Application

l Product

Silicon-Carbide

Benefits from material properties

Benefits

l Higher blocking voltage and better Ron

l Unipolar operation possible even for high voltage à reduced power loss and better efficiency l Faster switching at higher voltages

à leaner system design l Higher radiation robustness

physical properties 4H-SiC Si GaN

band gap [eV] 3.26 1.12 3.2

break through field [MV/cm] 2 0.25 ~2

thermal conductivity [W/cm/K] ~3.4 1.5 1.3 ideal bulk mobility [cm²/V/s] 800/115 1400/450 440/2DEG/- electron saturation vel. [cm/s] 2e7 1e7 2.2e7

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SiC- vs Si-power semiconductor devices

l Lower switching losses with unipolar operation

CoolSiC™ MOSFET

SiC benefits and target applications

… the ongoing major trend in designs is the increase of power density based on a reduction of switching losses, enabling smaller heatsinks, and also allowing higher operating frequencies, enabling smaller magnetics.

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SiC MOSFET Technology background

Basic challenge of planar SiC MOSFETs

l Defect density on the planar SiC – SiO 2 interface is very high in 4H-SiC

o Scattering of electrons in MOSFET channelà Reduction of electron channel mobility (µ e,ch )

à Reduced performance: channel resistance Ý. power losses Ý, channel current ß

e- e- e-

e- e-

e- e- e- e-

e- e-

e- e- e- e-

e- e-

2 nm SiO

2

4H- SiC

R_K

1

R_K2 Rn+

Rn+ RKanal

Metal

SiC (p-doped) SiC (n-doped) Silicon dioxide +V

_G

+V

_DS

HRTEM-image of the SiC/SiO

2

– interface.

Only solution : Apply high field across the

oxide for turn on - by higher V

_GS

or thinner oxide

Infineon solution to SiC MOSFET

- Trench-based structure Trench-MOS devices

lNo need to overdrive the gate oxide in forward mode

lNeed design measures to reduce electric field in blocking mode

Oxide stress in blocking mode due to the high internal field in SiC

Less critical because

- E-field reduction by design measures possible

- Full blocking voltage is applied only in exceptional cases during operation Oxide stress in forward mode due to

the need to compensate for the high channel defect density

Very critical because

lIn each on state the full stress is applied lNo possibility to use design measures

TMOS

n

^-

p

^ee

DMOS

n

^-

e e e e

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CoolSiC ^TM SiC MOSFET

Achieve safe oxide operation with low R on x A together

l SiC Trench-MOSFET: lowest Ron*A

l Restricted maximum operating electric field in gate oxide is key for assuring lowest failure rate in MOS-based devices

CoolSiC

^TM

trade-off curve for oxide stress in reverse mode

SiC MOSFET gate oxide reliability verification

Reference：Menia Beier-Moebius, Josef Lutz, "Breakdown of Gate Oxide of 1.2 kV SiC-MOSFETs Under High Temperature and High Gate voltage", PCIM Europe, 2016

Definition of SiC MOS gate oxide

intrinsic and extrinsic failure Gate test voltage profile

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Key characteristics of CoolSiC ^TM MOSFET

l R

_DS,on

*A=3mΩcm² (typical)

l R

_DS,on

=45mΩ @T

_vj

=25°C

l Increase by 50% @ 150°C l V

_GS,th

=4V (typical) @I

_D

=1mA, V

_DS

=V

_GS

l V

_F

=3.5V (typical) @I

_D

=10A, V

_GS

=-5V l Gate control window: 15V/-5V

l Gate charge: 45nC

Unique for SiC MOSFETs

Topics

l Technology

l Device characteristics l Application

l Products

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CoolSiC ^TM SiC MOSFET gate threshold V _GS(TH)

- Voltage range and temperature-dependencies

I

D

= 10 mA V

DS

=V

GS

栅极阈值电压VGS(th) (V)

结温：T

_j

(°C)

Gate-source threshold voltage I

D

= 10mA, V

DS

= V

GS

T

j

= 25°C 3.5 4.5 5.5

T

j

=175°C - 3.6 -

V

GS(th)

V

(tested after I

GSS

+15V XXX m s as precondition pulse)

l High V _GS(TH) provides high noise immunity ruggedness against switching transients

150 mil slim body package 1EDI20N12AF (2A) 1EDI60N12AF (6A)

CoolSiC ^TM SiC MOSFET Gate Driver IC

- 1EDI Compact Family

l CoolSiC ^TM SiC MOSFET gate characteristics compatible with IGBT gate drive windows : R DS(ON) specified at V GS = +15V

l High-speed IGBT gate driver can thus be used for CoolSiC ^TM SiC MOSFET l Coreless transformer designed for highest dv/dt – CMTI 100kV/µs l Short propagation delay (125 ns) and filter time for up to 4MHz switching

(D=0.5)

GND1 IN+

IN- VCC1

OUT+

VCC2

GND2 OUT-

+3V3

SGND IN

+15V

2R2 100n 4µ7

3R3

4µ7

-5V 0V

300 mil wide body package

1EDI20H12AH (2A) 1EDI60H12AH (6A)

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CoolSiC™ MOSFET loss characteristics

Benchmark in switching losses Threshold-free ON-state characteristic

0.0 10.0 20.0 30.0 40.0 50.0 60.0 70.0 80.0

0 1 2 3 4 5 6 7 8 9 10

On-State Current ID/ICinA

On-State Voltage VDS/VCEin V

Output Characteristic

Conduction losses comparison

- 1200V CoolSiC™ MOSFET vs H3 IGBT & 1000V/30A Si MOS

SiC TMOS

IMW120R45T1 TO247

H3 IGBT

IKW40N120H3 TO247

actual Irms

Comparison to a 1200V IGBT

l Resistive output characteristic for SiC TMOS versus, the diode-like voltage drop Vcesat of IGBT (typically1V~2V) increase logarithmically with current.

l Lower conduction losses below the rated current (25A at 175°C)

l For component selection, lower current derating applied for SiC MOSFET compared to Si IGBT due to low switching losses

Si MOS 1000V 30A

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Switching Losses: E _on and E _off

Comparison with a H3 IGBT

(same SiC SBD used for commutation!) o Temperature dependency of

MOSFET relatively small oE off drastically lower – Factor 5 at low temperature – Factor 10 at high temperature

(due to bipolar nature of IGBTs) oE on around 25-50% lower when commutating against the same SBD

Temperature dependency

Note: Commutation against the same SiC SBD

TO247-4pin: Extra driver source pin enable further switching loss reduction

CoolSiC™ MOSFET 45 mW – 4pin

CoolSiC™ MOSFET 45 mW – 3pin

Tj=175°C, Vds=800V, Rg=4.5 Ohm, Vgs=-5/+15V, FWD=SiC 20A

Eoff -10%

Eon -40%

l The right package is key to a full utilization of SiC benefits

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Switching characteristics

l Switching characteristics are controllable by R _G,ext (4.5Ω and 10.2Ω in the examples)

turn-on 20 A / 800V turn-off

Dynamic characteristics E _sw vs Rg

- Very good controllability with Rg

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Dynamic characteristics dv/dt vs Rg

- Very good controllability by Rg

dv/dt is fully controllable by R _G

Summary

Features and key benefits

Unique SiC MOSFET characteristics vs traditional 1200 V silicon devices l Low Q

g

and device capacitances

l Almost no reverse recovery losses of body diode

l Temperature independent switching losses l Knee-voltage free on-state characteristic compared to IGBT

CoolSiC

^TM

unique SiC MOSFET advantage

l Superior gate oxide reliability

l Best-in-class switching and conduction losses l Higher transconductance gm (gain)

à simple gate drive

l High threshold voltage V

th

=4 V

l Application-oriented short-circuit robustness l IGBT compatible gate driving: +15/-5 V

Key Benefits

l Best in class system performance l Highest efficiency for reduced

cooling effort

l Higher frequency operation l Reduction in system cost l Increased power density l Reduced system complexity l Longer lifetime and higher

reliability

l Ease of design and implementation

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Topics

l Technology

l Device characteristics l Application

l Product

Switching loss reduction possibility

› Hybrid solution – Recovery loss

reduction – Eon reduction

› Full SiC solution – Recovery loss

reduction – Eon reduction – No tail current – Reduced on state

losses

Switching loss reduction by 80% possible with fast switching SiC MOSFET

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Loss reduction possible even with slow switching speed

l Hybrid solution – Recovery loss

reduction – Eon reduction

l Full SiC solution – Recovery loss

reduction – Eon reduction – No tail current – Reduced ON-state

losses

50% loss reduction feasible even with IGBT-like slow dv/dt (<5kV/µs) operating at 5 kHz

H3 + Rapid 1 TMOS + Rapid 1 TMOS + Gen 5

C ir cu it

1200V

Switch

1200V 40A H3 IGBT

IKW40N120H3 1200V 45mΩ SiC TMOS

IMW120R045T1 1200V 45mΩ SiC TMOS IMW120R045T1

650V

Switch

650V 30A S5 IGBT

IKW30N65ES5 650V 30A S5 IGBT

IKW30N65ES5

650V

Diode

650V 30A Rapid1 Diode

co-packed w/ IKW30N65ES5 650V 30A Rapid1 Diode

co-packed w/ IKW30N65ES5 650V 16A Gen5 SBD IDH16G65C5

fsw

24kHz 24kHz

48kHz 72kHz

24kHz 48kHz 72kHz

Performance comparison in NPC2 (3-level T-Type topology

Conditions

IKW40N120H3

IKW30N65ES5

IMW120R045T1

IKW30N65ES5

IMW120R045T1

30A S5 IGBT 16A Gen5 SBD

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IMW120R045T1/IKW40N120H3 w/ IKW30N65ES5(+IDH16G65C5): V_IN=700V-740V, VOUT=230V, VGS=-5/15V, R_G=2.2Ω; T-NPC application test, Villach (K. Sobe)

Performance in a 3L T-Type Topology

All solutions at 24kHz

› Drastically higher efficiency with SiC based solutions (at 4 kW output power) – 0.5% with TMOS+S5+Rapid1 – 0.7% with TMOS+S5+Gen5

› Drastically higher output power with SiC based solutions (for T

max

=100°C) – 1.0 kW with TMOS+S5+Rapid1 – 1.5 kW with TMOS+S5+Gen5

H3+Rapid1

TMOS+Gen5 TMOS+Rapid1

Replacing the outer 1200V H3 IGBT with a 1200V SiC TMOS results in drastically higher efficiency and output power!

!

Performance in a 3L T-Type Topology

SiC@48kHz vs. Si@24kHz

› SiC-based solutions enable to go to higher frequencies compared to a pure IGBT solution

– TMOS+S5+Rapid1@48kHz gives a similar efficiency as the pure IGBT solution at 24kHz!

– TMOS+S5+Gen5@48kHz gives a 0.4-0.5% better efficiency then the pure IGBT solution at 24kHz

H3+Rapid1

@24kHz

TMOS+Gen5

@48kHz

TMOS+Rapid1

@48kHz

IMW120R045T1/IKW40N120H3 w/ IKW30N65ES5(+IDH16G65C5): VIN=700V-740V, VOUT=230V, VGS=-5/15V, RG=2.2Ω; T-NPC application test, Villach (K. Sobe) Replacing the outer 1200V H3 IGBT with a 1200V SiC TMOS allows to double the switching frequency without giving up on efficiency!

!

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Performance in a 3L T-Type Topology

SiC@72kHz vs. Si@24kHz

› SiC-based solutions are still

competitive at 72kHz, especially with SBDs in the NPC path

› TMOS+S5+Gen5 @72kHz still gives a better efficiency (~0.2%) than the pure IGBT solution at 24kHz

H3+Rapid1

@24kHz TMOS+Gen5

@72kHz

TMOS+Rapid1

@72kHz

IMW120R045T1/IKW40N120H3 w/ IKW30N65ES5(+IDH16G65C5): V_IN=700V-740V, VOUT=230V, VGS=-5/15V, R_G=2.2Ω; T-NPC application test, Villach (K. Sobe) Using a 1200V SiC TMOS as outer switch and Gen5 SBDs in the NPC path allows to triple the switching frequency and gives a better eff.

!

Conclusion

With latest CoolSiC

^TM

SiC MOSFET technology

lSiC MOSFET gate-oxide reliability problem overcome by trench-gate structure lSiC MOSFET with IGBT-compatible gate characteristics offer operational robustness

lThreshold-free conduction loss

lAuxiliary source pin for gate drive further reduce switching losses lDynamic characteristics fully-controllable by Rg

lSignificant loss reduction possible even at low switching frequency of 5kHz lSiC MOS @72kHz still gives better efficiency than pure IGBT solution at 24kHz in NPC-2 topologies

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Topics

l Technology

l Device characteristics l Application

l Product

CoolSiC™ MOSFET First products

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Demo and reference design

Standard BUCK or Boost

demo kit 20KW B6 High frequency Bi-directional inverter reference design

12pcs IMZ120R041M1

Product information

› Special webpage for CoolSiC™ MOSFET – www.infineon.com/coolsic

› Product brief CoolSiC™ MOSFET – lead product promotion

› CoolSiC™ Brochure

– SiC… MOSFET, Driver, Diode

› Different publications

– The future of power semiconductors – CoolSiC MOSFET revolution to rely on – Various conference papers

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Upcoming information and material

CoolSIC™

MOSFET overall

Evaluation Board Discrete

TO-247

Evaluation Board Module Easy1B FF11

Application Notes and Evaluation Boards

Gate drivers for SiC MOSFETs

› Documentation material and Boards available for PCIM Shanghai

Infineon‘s SiC-MOSFET status: we are going to combine safe oxide operation with low R _on x A

IFX trade off for oxide stress in reverse mode

l IFX SiC-Trench-MOSFET: lowest R _on *A PLUS lowest oxide field in on state l Restricted maximum operating field for the oxide is key for assuring lowest

FIT rates in MOS based devices è use of thick oxides !!

Revolution to rely on.

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Technology, Device and Application CoolSiC SiC MOSFET TM

CoolSiC TM SiC MOSFET