Present
PresentStatus
StatusAnd
AndFuture
FutureProspects
Prospectsof
ofSiC
SiCPower
PowerDevices
Devices
Contributors :
Gourab Majumdar
Chief Engineer,
Power Device Works, Mitsubishi Electric Corporation, Japan
John Donlon
Senior Application Engineer,
Powerex Inc., U.S.A.
Eric Motto
Principal Application Engineer,
Powerex Inc., U.S.A.
Tatsuo Ozeki
Project Manager, SiC Project Group,
Advanced Technology R & D Center, Mitsubishi Electric Corporation, Japan
Hidekazu Yamamoto
Manager, Power Device Development Dept.,
Power Device Works, Mitsubishi Electric Corporation, Japan
Makoto Seto
Manager, Power Electronics System Development Center,
Advanced Technology R & D Center, Mitsubishi Electric Corporation, Japan
Abstract:
At Mitsubishi, R & D work on SiC Power Devices has been continuing for several
years through implementation of in-house strategic projects and by active participation
in national projects in Japan. Through these activities, advanced high performance
MOSFET and Schottky Barrier Diode devices of 1200V-2000V class have been
developed.
In this presentation, the technical results of these activities will be briefly explained.
The conceptual aspects and performance-related evaluation results of some
experimental SiC-MOSFET and SiC-SBD device structures will be shown.
It will conclude with some discussion of existing issues and possibilities concerning
SiC power devices becoming the future de facto solution in the industry.
Present
PresentStatus
StatusAnd
AndFuture
FutureProspects
Prospectsof
ofSiC
SiCPower
PowerDevices
Devices
„
„
„
„
Introduction
Device Achievements & Needs
Future Prospects of SiC Power Devices
Conclusion
Evolution
Evolution of
of Power
Power Devices
Devices
1950
1970
First Wave
(Uncontrollable
Latching
Devices)
Triac
Thyristor
1980
1990
RC
Thyristor
Light Trig. Thyristor
Second Wave
(Controllable
Non-Latching
Devices)
GTO
Bipolar
Transistor
SIT
Bipolar Tr. Module
1991
1991 :: Second
Second Generation
Generation MOSFET
MOSFET &
& IGBT
IGBTPower MOSFET
(5μm
(5μm design
design rule).
rule).
Third Wave
(MOS-Gate
Controlled
Devices &
Power ICs)
2000
1993
1993 :: Third
Third Generation
Generation MOSFET
MOSFET &
& IGBT
IGBT
(3μm
(3μm design
design rule).
rule).
GCT
High β
Bip. Tr. Module
Power MOS.
Module
Trench MOS
Sub µm MOS
IGBT
1995
1995 :: Fourth
Fourth Generation
Generation MOSFET
MOSFET
IGBT
Module
(1.5μm
(1.5μm design
design rule).
rule).
1995
1995 :: Fourth
Fourth Generation
Generation IGBT
IGBT
(1μm
(1μm design
design rule;
rule; Trench
Trench Version).
Version).
1997
1997 :: Fifth
Fifth Generation
Generation MOSFET
MOSFET
(1μm
(1μm design
design rule).
rule).
1999
1999 :: Fourth
Fourth Generation
Generation IGBT
IGBT
(1μm
(1μm design
design rule;
rule; Planar
Planar Version).
Version).
*Note: ASIPM ≡ Mitsubishi’s Application Specific Intelligent Power Module.
TM
CSTBT ≡ Mitsubishi’s Carrier stored trench gated bipolar transistor.
“..Generation” ≡ The denominations refer to Mitsubishi’ s technologies.
Trench IGBT
Sub µm IGBT
CSTBTTM *Note
IPM;
ASIPM *Note;
System
DIP-IPM;
Integrated
HEV-IPM;
Solutions
HVIPM;
Power ICs New Devices
(SiC Devices)
IPM Introduction by Mitsubishi
Reduction of IGBT operation losses
1985
1st Gen
Power Loss
(W)
100W
IGBT
turn-off
loss
1990
2nd Gen.
E series
Ov
er a
ll p
o
75W
1995
3rd Gen.
H series
2000
4th Gen.
F series
5th Gen.
NF series
Power losses in
inverter application
we
r lo
ss
IGBT
conduction
loss
re d
uce
d
50W
to 1
40W
2nd Gen.
Planar gate
3rd Gen.
4th Gen.
Device using
new material
Simulated Conditions
Device Ratings = 75A, 600V
Application : VVVF Inverter Circuit
Inverter Output Current,Io = 45Ar.m.s.
Control Scheme = PWM, Sinusoidal
Carrier frequency,fc = 15kHz
Power factor, φ = 0.8
/3
33W CSTBTTM
IGBT
turn-on
loss
1st Gen.
2005
5th Gen.
Trench gate
Static characteristics of Si & SiC devices compared with theoretical limits
Relationship between specific on-resistance and breakdown voltage
Specific Ron (mohm-cm2)
1000
Silicon Unipolar Limit
HV-Thyristor/GTO family
Super Junction
MOSFET
HV-IGBT
IGBT-2G
100
IGBT-3G
Power MOSFET
10
CSTBTTM
Estimated
PiN Diode
Limit (Bipolar)
1
Super Junction
Unipolar Limit
4H-SiC Unipolar Limit
(Estimated for Jp=1μm）
Compared at Tj or Tch = 400K
0.1
10
100
1000
10000
Breakdown Voltage　(V)
In terms of power losses, the users have benefited from continuous improvement made by
various generations of IGBT families over the past 20 years
Power
PowerDensity
DensityEnhancement
Enhancementfor
forMedium
MediumPower
PowerPE
PEEquipment
Equipment
Power
Density (w/cc)
パワー密度　[W/cc]
100
M-Converter
Inverter
• Efforts toward
HEV Inverter SiC Application
• Integration
M-Converter
Technology
（RB-IGBT)
• New Packaging
Technologies
Gen-purpose Inverter
10
( DIP-IPM )
1
Note:
IPM: Intelligent Power Module
DIP-IPM: Dual In-line Package IPM
EV-IPM: IPM for EV and/or HEV applications
RB-IGBT: Reverse Blocking type IGBT
RC-IGBT: Reverse Conducting type IGBT
M-Converter: Matrix Converter
HEV Inverter: Inverter systems for hybrid vehicles
0 .1
0 .0 1
1980
HEV Inverter
( EV-IPM )
Gen-purpose Inverter
( IPM )
Gen-purpose Inverter
( Bipolar )
Gen-purpose Inverter
( RC-IGBT & others )
1990
2000
年
Year
2010
2020
Comparison
Comparison of
of Device
Device Structure
Structure and
and
Distribution
Distribution of
of Electric
Electric Field
Field
SiC
Si
source
Breakdown Electric Field x 10
source
source
gate
+
p n
n+ p
E
n-
SiC
Distribution of
electric field
n- Si drift layer
(very low carrier
concentration)
～
～
Si substrate
drain
Si
～
～
gate
+
p n
n-
source
n+ p
n-SiC drift layer
～
～
SiC substrate
drain
drift layer thickness: very thin
carrier concentration: very high
= Drastic reduction of On-state Loss
～
～
Merits of SiC Devices
6
Diamond
5
1.89Å
SiC Poly types
4
3
4H-SiC
3C-SiC
6H-SiC
On-state voltage [V]
Critical Electrical Breakdown Field [MV/cm]
Ideal SiC devices for power applications
10
Si-GTO
Si-IGBT
SiC-IGBT
1
Si-MOSFET
SiC-MOSFET
0.1
1
10
Breakdown voltage [kV]
2
Low loss, high voltage
SiC devices
Wide bandgap
High critical BV
1
2.35Å
Si
0
1
2
3
4
Bandgap [eV]
5
6
Physical
Physicalparameters
parametersof
ofdifferent
differentmaterials
materials
and
andexpectations
expectationsfrom
fromSiC
SiC
Material
Saturated
Breakdown
Thermal
FOM
Electron Drift
Electric Field
Conductivity 【λ＊Johnson FOM】
Velocity
Bandgap
Energy
Dielectric
Constant
Electron
Mobility
Eg
εr
μn
(dimension)
2
cm /Vｓ
10 Ｖ/cm
10 cm/s
W/cm.K
11.9
9.5
9.7
9.7
9.7
1500
900
800
1000
460
0.3
2.6
3.0
3.5
3.0
1.0
2.5
2.7
2.7
2.0
1.5
1.3
4.9
4.9
4.9
eV
1.1
3.4
2.2
3.0
2.9
4H-SiC : Silicon
Si
GaN
3C-SiC
4H-SiC
6H-SiC
Low On-resistance
(approx. 1/100 of Si）
Εc
νsat
6
λ
7
【 λ＊（Ec＊
‫ע‬sat）2 】
1
407
2381
3241
1307
• Higher voltage > 10kV
• Higher current density
High Breakdown Voltage (approx. 10x of Si)
High Thermal Conductivity (approx. 10x of Si)
System Merits
Loss reduction
Down sizing
Cost reduction
Capacity of applied system (VA)
High temp. operation (approx. 3x of Si)
• Voltage driven device (MOSgated)
• Higher voltage, higher current
• On-state resistive loss reduction
DC transmission
Steel mill
traction
• MOSFET-like fast switching speed
• Simple forced air cooling realized
by higher Tj operation
Automotive
Inverter
UPS
Operation frequency (Hz)
• MOSFET-like
fast speed
• Lower power loss
• Higher junction
temperature
Silicon
Silicon Carbide
Carbide RR && DD status
status
epi-layer
channel
Specific on-resistance (mΩcm2)
100
Si-limit 1/10 of Si-limit1/100 of Si-limit
source
gate
p-body
contact
Al-implanted p-body
Mitsubishi (2002)
n-drift layer
n-SiC substrate
drain
Previous work
4H-SiC(2002)
Double Implanted OSFET
VBr=1900V Ron=40mΩcm2
1. High voltage vertical
structure
2. Double implantation
3. Epilayer channel
-High quality
-Doping control
4. JTE termination
10
SiC
4H 6H
MOSFET
Schottky
Mitsubishi (2002)
SiC-limit
1
500
1000
2000
5000
Breakdown voltage (V)
High Temp
Epitaxial Growth
Previous work
(2002)
4H-SiC
Schottky Barrier Diode
VBr=1500V Ron=3mΩcm2
Electrical characteristics of initial
4H-SiC Power MOSFET test element
Initial work (2002)
Ron=40mΩcm2
ドレイン電流 (mA)
20
Drain current (mA)
Vg=20V
Vg=25V
10
1x10
-2
-3
8x10
-3
6x10
-3
Vg=15V 4x10
Vb=1900V
-3
2x10
Vg=10V
0
0
1
Vg=0.5V
2
Drain-Source Voltage (V)
Vg=0V
0
0
1000
2000
Drain-Source Voltage (V)
Ron = 40mOhm.cm2 BV = 1900V
Silicon
SiliconCarbide
CarbideRR&
&DDgoals
goals
Si-limit
Specific on-resistance (mΩcm2)
100
1/10 of Si-limit 1/100 of Si-limit
Mitsubishi 2001
mobility=20cm2/Vs channel length=3µm
Mitsubishi 2002
mobility=100cm2/Vs channel length=3µm
mobility=100cm2/Vs channel length=1µm
10
Mitsubishi
SiC-limit
MOSFET
Schottky
1
500
1000 2000
5000
Breakdown voltage (V)
Silicon
SiliconCarbide
CarbideRR&
&DDgoals
goals
New SiC High Voltage MOSFET Development
Present target (2004)
Gate Pad
Source Metal
Contact Hole
Poly Si Gate
Epitaxial Channel
p++
n+
p+
n+
p+
Channel Area
p++
Source Area
n- Epitaxial Layer
n+ SiC Substrate
Al source
electrodes
１mm
Drain Metal
２５μm
Gate length: 2μm
SiC MOSFET Cell Structure
4H-SiC High Voltage MOSFET
(Experimental chip)
(Performance :1200V, 13mΩ・cm2)
Performance of a 30A/600V
4HSiC-SBD chip (experimental)
SiC
SiCapplication
applicationexample
example(Future)
(Future)
High performance PFC-Inverter for Air-conditioning
PFC Circuit
(High frequency, Low loss requirement)
P
Inverter Circuit
DC 300-400V
(controllable)
P
DIP-IPM
Relay
N/F
R
LVIC
ACL
S
Q2
Co’
Co
M
Q1
AC 90-264V
N
(universal)
N2
Preferable device: SiC-SBD
N
HVIC HVIC HVIC
Control
Possible module packaging
●CompactPFC-Inverter
PFC-Invertersystem
system
●Compact
●Completeclear
clearofofharmonic
harmonic
●Complete
currentregulation
regulation
current
●
High
performance
PAMcontrol
control
● High performance PAM
Highsystem
systemefficiency
efficiency
●●High
Co’’
MCU
IC
DIP-PFC
Use of DIP-IPM concept
DIP-IPM
LVIC
- Predicted system benefits - based on simulation using 1200V device designs Conditions for Simulation:
Inverter Operation Loss ［Ratio］
1.20
Vcc=600V, Irms=31A, Modulation ratio=1.0
Power Factor=0.8, fc=20kHz (Sinusoidal PWM)
SiC-MOSFET Ron=5mΩcm2@25℃ (Note-2)
SiC-SBD Ron=3mΩcm2@25℃ (Note-2)
Note:
Si-CSTBT＋Si-FWDi
Device active area : 1
1.00
1) Exsisting Silicon-IGBT based system's device
loss at Tj=125℃/fc=20kHz operation is
referenced as unity for comparison.
2) Assumed values for simulation purpose.
0.80
0.60
0.16
0.40
0.25
0.50
0.20
SiC-MOSFET＋SiC-SBD
Device active area
0.00
75
100
125
150
175
200
225
250
275
Junction Temp. [℃]
High temp. operation will allow chip
size reduction and attribute to lower
power losses, simultaneously.
• Higher power density
• Simpler hardware for
thermal management
System Cost
Reduction
- Predicted system benefits - based on simulation using 1200V device designs Adoption of high
frequency control
1.20
Reduces size/weight of
peripheral components
Si-CSTBT＋Si-FWDi
Inverter Operation Loss ［Ratio］
1.00
Vcc=600V, Irms=31A, Modulation ratio=1.0
Power Factor=0.8, fc=Vriable (20-100kHz)
SiC-MOSFET Ron=5mΩcm2@25℃ (Note-2)
SiC-SBD Ron=3mΩcm2@25℃ (Note-2)
SiC device active area
= 25% of Si-IGBT device active area
Note:
1)Existing Silicon-IGBT based system's device loss
(limited to roughly 20kHz)
Device active area : 1
Conditions for Simulation:
System Cost
Reduction
at Tj=125℃/fc=20kHz operation is referenced as
unity for comparison.
2) Assumed values for simulation purpose.
100ｋHz
0.80
0.60
50ｋHz
0.40
20ｋHz
0.20
SiC-MOSFET＋SiC-SBD
Device active area ：0.25
0.00
75
100
125
150
175
200
Junction Temp. [℃]
225
250
275
- Predicted system benefits Si vs. SiC comparison for 460V/22kW/3-ph MC
(5th
Si-IGBT Module
Gen. Dual 100A/1200V)
Volume ratio
= 1/3
Power-loss ratio = 0.4
SiC-MOSFET Module
(Dual 100A/1200V)
Operating Tj = 125 deg. C
Operating Tj = 250 deg. C
Cooling fans
Forced air-cooling
Natural air-cooling
3-ph inverter using silicon
3-ph inverter using SiC
(state-of-the-art)
(Future prediction)
Predicted
PredictedMajor
MajorApplications
Applicationsof
ofSiC-MOSFET
SiC-MOSFET
Motor Controls and Power Supplies
Applications
Home Appliances
（refrigerator, air-conditioner, and washing
machines）
Automotive (EV, HEV, and FCV)
Elevators, UPS and Factory Automation,
Power supplies, Alternative energy sources
Electric Railway Systems, Metal Industries
Power network, Utilities
Voltage Ratings
600 V
600-1200 V
600-1700 V
1200-6500 V
> 10kV
The
Thekey
keyissues
issuesand
andprojections
projections
30
25
6
5
4
Diameter A
Diameter B
20
Diameter C
15
Pipe density (MPD) for A
3
10
2
5
1
1995
1997
1999
2001
2003
2005
2007
2009
2011
MPD (cm-2)
Wafer Diameter(inch）
(1) Pipe density reduction
(2) Wafer diameter increment
0
Year
(Data from ICSCRM 2001)
Scenario
Scenario for
for application
application of
of SiC
SiC devices
devices
Higher reliability, Simpler
system design, Safer Operation
High cost
Cost issue
Normally Off type preferred Higher power,
Higher voltage
> 5000V
Traction, Large
Motor Drives
>1700V
Motor Drives
for Industry
Lower cost
Home
Appliances
<600V
600V-1200V
Automotive
(EV,HEV,FCV)
600V-1000V
Uninterruptible
Power Supplies
(UPS)
Adequate performance in
harsh application surroundings
High voltage
High power
V-I rating issue
Power Transmission
600V-1200V
Low voltage
Low power
Low cost
Reliability issue
High grade
Power
PowerDevice
DeviceDevelopment
DevelopmentRoadmap
Roadmap
Functions / Performance
Key Power Devices
SiC-FET, SiC-SBD,
Intelligent devices
Key Power Devices
Reverse Conducting IGBT
Reverse Blocking IGBT
Intelligent devices
Key Power Devices
al
i
r
te
a
MKey Processes
w
Ne
SiC wafer process
Hi-speed epitaxial growth
Hi-grade oxide formation )
it y
l
i
t
a Key Processes
s
r
Deep-Trench Structure
Ve
LPT-CSTBT
MPS-Diode
Sub-micron MOSFET
Ultra-thin wafer
Backside diffusion
Multi-layered connections
e
n
i
f
e
R
s Key Processes
s
e
c
Sub-micron Cell-Trench Structure
o
r
P
Denominations :
LPT-CSTBT: Light Punch-through CSTBT
MPS-Diode : Merged PiN Schottky Diode
SiC-FET : Silicon Carbide FET
SiC-SBD : Silicon Carbide Schottky Barrier Diode
Thin wafer
2002
2003
2004
2005
2006
2007
2008
(FY)
and