Wide band-gap Power Semiconductor Devices
Silicon Carbide
for Power Semiconductor Devices
Philippe Godignon
Centro Nacional de Microelectrónica, CNM
CNM-CSIC, Campus Universidad Autónoma de Barcelona,
08193 Bellaterra, Barcelona, Spain
SAAIE’06, Gijón , 15th September 2006
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Wide band-gap Power Semiconductor Devices
Outline
• Introduction
• SiC properties
• 10V-300V: SiC or Si
• 300V-3500V : Unipolar devices:
• > 3500V: Bipolar devices ?
• Future Trends
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Wide band-gap Power Semiconductor Devices
Introduction
What is Driving Future Power Electronics?
• Power electronics holds the key to annual energy savings of
around $400 billion!
• Lightweight, high performance products such as mobile
computing, home entertainment and power tools
• High efficiency, high power density electric drives in
products such as air conditioning
• Proliferation of automotive and aerospace electronic systems
• Increased use of power electronics in transmission and
distribution systems
• Energy storage systems
• …
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Wide band-gap Power Semiconductor Devices
•
•
•
•
•
•
Introduction
Increased power densities
Lower electromagnetic emissions
Plug-and-go systems
Extreme operating environments
Higher levels of integration
Lower cost
Moore law for power devices:
Doubling frequency and power
density every 4.5 years
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Wide band-gap Power Semiconductor Devices
Introduction
Why SIC ?
• Si devices are generally limited to operation at junction
temperatures in the range of 200ºC.
• Si power devices not suitable at very high frequencies.
• SiC, GaN and Diamond offer the potential to overcome both the
temperature, frequency and power management limitations of
Si.
• At present, SiC is considered to have the best trade-off between
properties and commercial maturity with considerable potential
for both HTE and high power devices.
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Introduction
Wide band-gap Power Semiconductor Devices
Why SIC ?
Physical properties of various semiconductors for power devices
Material
Eg (eV)
@300K
(cm²/V.s)
µn
(cm²/V.s)
µp
vsat
(cm/s)
Ec
(V/cm )
(W/cm.K)
εr
Si
1.12
1450
450
107
3×105
1.3
11.7
GaAs
1.4
8500
400
2 × 107
4×105
0.54
12.9
3C – SiC
2.3
1000
45
2.5 × 107
2 × 106
5
9.6
6H – SiC
2.9
415
90
2 × 107
2.5 × 106
5
9.7
4H - SiC
3.2
950
115
2 × 107
3 × 106
5
10
GaN
3.39
1000
350
2 × 107
5 × 106
1.3
8.9
GaP
2.26
250
150
107
1.1
11.1
Diamond
5.6
2200
1800
5.6 × 107
20
5.7
3 × 107
λ
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Introduction
Wide band-gap Power Semiconductor Devices
Why SIC ?
Physical properties of various semiconductors for power devices
Material
Eg (eV)
@300K
(cm²/V.s)
µn
(cm²/V.s)
µp
vsat
(cm/s)
Ec
(V/cm )
(W/cm.K)
εr
Si
1.12
1450
450
107
3×105
1.3
11.7
GaAs
1.4
8500
400
2 × 107
4×105
0.54
12.9
3C – SiC
2.3
1000
45
2.5 × 107
2 × 106
5
9.6
6H – SiC
2.9
415
90
2 × 107
2.5 × 106
5
9.7
4H - SiC
3.2
950
115
2 × 107
3 × 106
5
10
GaN
3.39
1000
350
2 × 107
5 × 106
1.3
8.9
GaP
2.26
250
150
107
1.1
11.1
Diamond
5.6
2200
1800
5.6 × 107
20
5.7
3 × 107
λ
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Introduction
Wide band-gap Power Semiconductor Devices
Why SIC ?
Physical properties of various semiconductors for power devices
Material
Eg (eV)
@300K
(cm²/V.s)
µn
(cm²/V.s)
µp
vsat
(cm/s)
Ec
(V/cm )
(W/cm.K)
εr
Si
1.12
1450
450
107
3×105
1.3
11.7
GaAs
1.4
8500
400
2 × 107
4×105
0.54
12.9
3C – SiC
2.3
1000
45
2.5 × 107
2 × 106
5
9.6
6H – SiC
2.9
415
90
2 × 107
2.5 × 106
5
9.7
4H - SiC
3.2
950
115
2 × 107
3 × 106
5
10
GaN
3.39
1000
350
2 × 107
5 × 106
1.3
8.9
GaP
2.26
250
150
107
1.1
11.1
Diamond
5.6
2200
1800
5.6 × 107
20
5.7
3 × 107
λ
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Introduction
Wide band-gap Power Semiconductor Devices
SiC
xFET
SiThyristor
Potential of the
CoolMOS
Technology
Si- IGBT
(low loss)
50
Blocking voltage
1000 V
Chipsize
Current (A)
40
30
spec. Resistance
achieved with
Infineon VJFET (fast
topology) 2004
1 cm2
Losses at 50A
Si-MOSFET
P=UxI
20
500W
10
200W
75W
0
1
2
Voltage (V)
3
4
5
50W
25W
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Introduction
Specific on-resistance (mOhmcm2)
Wide band-gap Power Semiconductor Devices
1000
SIAFET (Kansai/Cree)
SIAFET (Kansai/Cree)
DMOSFET (Cree)
DMOSFET (Cree)
TI-JFET (Rutgers)
SEMOSFET (Kansai/Cree)
trench MOSFET (Purdue)
SEJFET (Kansai/Cree) trench MOSFET (Purdue)
VJFET (Siemens)
DMOSFET (Siemens)
DMOSFET (Siemens) TI-JFET (Rutgers)
100
trench ACCUFET (Purdue)
10
VJFET (Siemens)
VJFET (Siemens)
trench ACCUFET (DENSO)
4H-SiC limit
Si limit
1
100
TI-JFET (Rutgers)
1000
V
BR
10000
(V)
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Introduction
Wide band-gap Power Semiconductor Devices
SiC Material
• Achievements in SiC bulk material growth and in SiC process technology.
− 3” SiC wafers with very low micropipe density (0.75 cm-2) available in
the market → high yield manufacturing process of large area SiC power
devices.
− 4” SiC wafers are already in the market and it is expected that the very
low micropipe density target will be achieved soon.
− 6” SiC wafers in 2008
• GaN: 2” wafers
(poor quality, high cost)
Diamond: 1cm x 1cm samples
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Wide band-gap Power Semiconductor Devices
Wafer ∅ 75 mm
CNM large area diodes
2.56 < diodes area < 25 mm2
Introduction
Wafer ∅ 75 mm
SiCED-Infineon commercial JFETs
1 < JFETs area < 1.25 mm2
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Introduction
Wide band-gap Power Semiconductor Devices
Commercially available SiC devices and testing samples
Schottky diodes, MESFETs
Schottky diodes
JFETs testing samples
JFETs and hybrid cascode testing samples
Advanced R&D programs
DENSO
Kansai Electric Power (Kepco)
Acreo
Rockwell
United Silicon Carbide Inc
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Introduction
Wide band-gap Power Semiconductor Devices
Si power devices
10V – 200V : Schottky, MOSFET
300V-1000V: PiN
MOSFET/CoolMOS
IGBT
1200V – 6500V
PiN
IGBT
GTO
> 6500V
Fast switching
Gate control
High current
Serie connections
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 10V-200V
Low voltage range:
10V -200V
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 10V-200V
• Difficult to compete with Si
• High temperature applications could be
covered by SOI
• High power - high frequency RF
devices in SiC and GaN
• Low on resistance GaN switch
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Unipolar devices: 300V-3500V
Wide band-gap Power Semiconductor Devices
Medium voltage range:
300V – 3500V
• SMPS
• Motor integrated drives
• Hybrid cars (300-500V – 250C)
• More electric aircraft (270-800V – 300C)
• Space power applications
SiC Unipolar devices
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Unipolar devices: 300V-3500V
Wide band-gap Power Semiconductor Devices
SiC Schottky Diodes
• SiC SBDs commercially available since 2001. They range from the
initial 300 V-10 A and 600 V- 6 A to 20 A and recently 1.2 kV.
• SBDs can be advantageously
applied for blocking voltages
up to 3.5kV.
• Large area 3.5 kV – 10/20A
SBDs demonstrated at CNM
The 25 mm2 SBDs exhibit a
leakage current of 100 µA @
2 kV.
Manufac-turer
VBR
IN
IR
Vf
CREE
600V
1200V
1200V
10A
5A
20A
2V@175ºC
2.6V@150ºC
2.5V@150ºC
100uA
100uA
20uA
Infineon
300V
600V
600V
10A
4A,
16A
1.5V@150ºC
2V@150ºC
1.7V@150ºC
20uA
4uA
10uA
Microsemi
200V600V
1A
4A
1.6V@25ºC
1.7V@25ºC
20uA
20uA
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Unipolar devices: 300V-3500V
Wide band-gap Power Semiconductor Devices
300
3
Current (A)
HT package from Semelab
200
1.2 kV SBD
1.2 kV PN-Si
T = 20ºC
1
150
100
Voltage (V)
250
2
0
50
3
SBD
Current (A)
2
3
2
1
1
0
0
-1
-1
150n
300n
450n
600n
750n
0
900n
time (s)
-1
25ºC SiC
100ºC SiC -2
140ºC SiC
150ºC SiC -3
175ºC SiC
180ºC SiC
190ºC SiC -4
-2
-3
-4
-5
100n
PN-Si
200n
time (s)
-5
300n 100n
25ºC Si
50ºC Si
100ºC Si
120ºC Si
150ºC Si
200n
1.2kV Schottky
300n
time (s)
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 300V-3500V
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 300V-3500V
3.5kV: a limit for SiC Schottky diodes
IF (20ºC)
IF (125ºC)
104
JF(A) (per die)
IF(A) (module)
16
12
78
8
52
4
26
0
1
2
3
4
VF(V)
5
6
0
4.5kV Si IGBT +
SiC Schottky module
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 300V-3500V
SiC Junction Barrier Schottky diode
• Mixed Schottky diode + PiN diode:
The reverse leakage well maintained closer to the PiN
diode level but showing forward current densities reasonably
lower (20-30%) than those of the SBDs.
In forward mode at high temperature, the bipolar mode
allows a moderate current decreases unlike in pure Schottky.
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Unipolar devices: 300V-3500V
Wide band-gap Power Semiconductor Devices
SiC Junction Barrier Schottky diode
Design 2/3
Design 3/4
15
586
200ºC
0
195
200ºC
1
2
3
0
4
IA (A)
IA (A)
25ºC
0
586
10
391
JA (A.cm-2)
391
JA (A.cm-2)
10
5
15
25ºC
25ºC
5
195
200ºC
0
VAK (V)
S = 2.56 mm2
0
1
2
3
0
4
VAK (V)
- 1.2kV - 6A packaged JBS
- Good performance in temperature
- Temperature behaviour depends of the JBS diode design
- 10 A diodes have been realised
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Unipolar devices: 300V-3500V
Wide band-gap Power Semiconductor Devices
SiC Junction Barrier Schottky diode
10
1µ
T = 25ºC
T = 100ºC
T = 200ºC
T = 300ºC
JBS : LN = 4 µm, LP = 3 µm
5
10n
IA (A)
IK (A)
100n
1n
2
100p
10p
0
D1 JBS A : 0.64 mm
2
D2 JBS A : 0.16 mm
2
D3 Schottky A : 0.16 mm
2500
5000
VKA (V)
Reverse characteristics of the 4H-SiC JBS
of various areas fabricated at CNM.
0
-5
0
100n
200n
300n
400n
time (s)
Turn-off current waveforms of the JBS
diode (2.56 mm2, Ln=4µm, Lp=3µm) at
different temperatures.
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 300V-3500V
SiC Junction Barrier Schottky diode
- Interest in reverse mode (lower leakage current +
avalanche mode operation)
- Interest at high temperature: on-state is lower than
equivalent Schottky at 200ºC
- Interest for its surge current capability
- Interest for the 2.5-5kV range compared to pure Schottky
- Problem of forward mode degradation (Stacking faults) ??
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 300V-3500V
SiC Junction Barrier Schottky diode
- Interest in reverse mode (lower leakage current +
avalanche mode operation)
- Interest at high temperature: on-state is lower than
equivalent Schottky at 200ºC
- Interest for its surge current capability
- Interest for the 2.5-5kV range compared to pure Schottky
- Problem of forward mode degradation (Stacking faults) ??
New generation of Infineon “Schottky“ diodes
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Unipolar devices: 300V-3500V
Wide band-gap Power Semiconductor Devices
SiC Power Switches
Basic types of power switching devices
unipolar
MOSFET
bipolar
JFET
number of pn junctions
Non even
IGBT
Ö potential in SiC very high
Ö fast and low loss devices
possible
Ö technological maturity
achieved
Ö applications with high volume
already today visible
SCR
number of pn
Junctions even
BJT
Ö potential for SiC
only for very high Vbr (> 4 ... 10...kV)
Reasons :
1. Band gap approx. 3eV
Ö high threshold (IGBT, SCR , BJT)
2. P-Type acceptors with Ea >200meV
Ö high p-resistivity
Ö low current gain
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Unipolar devices: 300V-3500V
Wide band-gap Power Semiconductor Devices
INFINEON - SICED
50A 1200V SiC VJFET
Ron @25°C typ. 50mΩ
160
150A
VG: 0 .. -20 V, Step -2V
140
• very low Ron-values possible
• rugged Gate-structure
120
• excellent short circuit capability
100
Current (A)
JFET
• high temperatures possible
80
60
• unconventional technology
40
• normally on (?)
20
0
• new gate control
0
5
10
15
20
Voltage (V)
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Unipolar devices: 300V-3500V
Wide band-gap Power Semiconductor Devices
SiCED hybrid Si/SiC cascode electronic switch
Turn-off energy losses (J/cm2)*10
-4
Single switch fly-back converter built
using Si/SiC cascode
14
12
10
8
6
4
2
0
B
Trench
Normally-off
MOSFET
Multiple Hybrid JFET
Multiple
Si/SiC
"integrated" "discrete"
cascode cascode
cascode
1
2
3
4
5
The hybrid Si/SiC cascode combination is
the most efficient one
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 300V-3500V
SiCED hybrid Si/SiC cascode electronic switch
Compared to a COOLMOS-based
converter, the SiC-based one offers the
highest efficiency (about 90%)
All SiC sparse matrix converter: 100KHz – 1.5kW – efficiency 94%
1300V 4A SiCED Cascodes + 1200V 5A CREE Schottky diodes
More Electric Aircraft: 3 phases PWM rectifier 10kW – 500KHz – 480V
CoolMOS + SiC Schottky diodes : efficiency higher than 96%
Volume: 30% power circuit + cooling / 30% electrolitic capacitors /
30% EMC filter
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Wide band-gap Power Semiconductor Devices
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 300V-3500V
JFETs for Current Limiting for Power System Protection
•
•
•
Efficiency of both devices checked under working conditions: connected to
the mains.
The current limiter is plugged in series with the power supply and the load
(230V/5w bulbs).
SiC VJFET experimental response to a short-circuit.
CNM VJFET
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 300V-3500V
Short circuit protection demonstration :Transient
wave form (measurements)
(SC)
Short circuit (SC)
Fast current stabilisation : 1.4 µs
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 300V-3500V
INTEGRATION
2D-Directional current
limiter made of two devices
monothically integrated
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Unipolar devices: 300V-3500V
Wide band-gap Power Semiconductor Devices
INTEGRATION
2D-Directional current
limiter made of two devices
monothically integrated
Current sensor integrated
with VJFET
300m
6,6m
Symbole : JFET
Line
: Sensing Pad
250m
RT
5,5m
IDS (A)
200m
4,4m
TJ=190°C
150m
3,3m
100m
2,2m
50m
1,1m
0
0
1
2
3
4
5
6
VDS (V)
7
8
9
0,0
10
Current sensor reflect
perfectly the main
current of the JFET
Current sensor can be
also used as temperature
sensor
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 300V-3500V
MOSFET
• Simple planar structrue
• Voltage gate control
• Extensively used in Si technology
• Normally off
• Low channel mobility in SiC
• High temperature operation ?
• Gate reliability ?
CNM 3.5KV MOSFET
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Wide band-gap Power Semiconductor Devices
Unipolar devices: 300V-3500V
SiC Power MOSFET
CREE:
• 2.3KV-5A Ron=0.48 ohm (25ºC) 13.5mohm.cm2 , Ir=200uA
Cin=380pF, Cout=100pF, reverse transfer C=19pF (Vgs=0,
Vds=25V, 1MHz)
Infineon:
• 1200V-10A, Ron=0.27 ohm (25ºC) 12mohm.cm2
Denso:
• 1200V-10A, 5 mohm.cm2 (25ºC),
• 8.5mohm.cm2 (150ºC)
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Unipolar devices: 300V-3500V
Wide band-gap Power Semiconductor Devices
1200 V MOSFET (SICED):
Built-in Diode Turn-off
SiC-MOSFET
Halfbridge
SiCED
40
Reverse Current (A)
20
400
10
0
Qrr
-1 0
-2 0
-3 0
-4 0
1 3 ,9 0
di/dt = 850 A/µs
Tcase = 125°C
Qrr = 370 nC
(COOLMOS: 15 µC)
1 3 ,9 5
1 4 ,0 0
1 4 ,0 5
200
Drain Source Voltage (V)
600
30
0
1 4 ,1 0
T im e (µ s )
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Wide band-gap Power Semiconductor Devices
Bipolar devices: 3500V-6500V
> 3.5 KV
• Utilities / Power distribution
• Military platforms
• Traction / Transport
Bipolar devices ?
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Wide band-gap Power Semiconductor Devices
Bipolar devices: 3500V-6500V
SiC Rectifiers-PiN Diodes
• Main problem: reliability due to VF drift created by stacking
faults
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Wide band-gap Power Semiconductor Devices
Bipolar devices: 3500V-6500V
SiC Rectifiers-PiN Diodes
• Main problem: reliability due to VF drift created by stacking
faults
• The state-of-the-art device is a Cree 4.5 kV 4H-SiC PiN diode:
− VF = 3.2 V at 180 A (100 A/cm2)
− IR = 1 µA @ 4.5 kV
− Chip area = 1.5 cm × 1.5 cm
− At a dI/dt = 300 A/µs, the diode shows a reverse recovery
time of 320 ns.
− 57% of diodes show no measurable increase in VF following
a 120 hours DC stress at 90 A.
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Wide band-gap Power Semiconductor Devices
Bipolar devices: 3500V-6500V
SiC Bipolar Transistor
• Unlike Si BJTs, SiC BJTs do not suffer from secondary breakdown.
• State-of-the-art BJT [S. Krishnaswami et al., ISPSD’2006, pp. 289-292]
− 4 kV, 10 A BJT
− βmax = 34
− Chip area = 4.24 mm × 4.24 mm
− IR =50 µA @ 4.7 kV
− turn-on time = 168 ns @ RT
− turn-off time = 106 ns @ RT
It will take some time to industrialize HV bipolar SiC switches
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Wide band-gap Power Semiconductor Devices
Bipolar devices: 3500V-6500V
SiC Bipolar Transistor
• Unlike Si BJTs, SiC BJTs do not suffer from secondary breakdown.
• State-of-the-art BJT [S. Krishnaswami et al., ISPSD’2006, pp. 289-292]
− 4 kV, 10 A BJT
− βmax = 34
− Chip area = 4.24 mm × 4.24 mm
− IR =50 µA @ 4.7 kV
− turn-on time = 168 ns @ RT
− turn-off time = 106 ns @ RT
− β ⇓50% under forward stress:
stacking faults in the base-emitter
region
It will take some time to industrialize HV bipolar SiC switches
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Bipolar devices: 3500V-6500V
Wide band-gap Power Semiconductor Devices
SiC Thyristor
• State-of-the-art SiC Thyristor
− 4.5 kV, 120 A SICGT (SiC Commutated Gate turn-off Thyristor)
− Chip area 1cm x 1cm
− IR < 5×10-6 A/cm2 @ 4.5 kV and 250ºC
− turn-on time = 0.2 µs - turn-off time = 1.7 µs
− Coated with a new high heat resistive resin capable of operating
at 400ºC
• 110 kVA PWM 3 phase inverter demonstrator using six SICGT
modules (one SICGT + two 6 mm × 6 mm SiC pn diodes in a
metal package). 2us turn-off time – No snubber
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Bipolar devices: 3500V-6500V
Wide band-gap Power Semiconductor Devices
SiC JFET Multi-cascode
Example: 4.5kV, 3-stage device
((1.15 Ω) 8,2mm² active SiC area
in each stack, ECSCRM 02)
10
2,0
Vgs=10V, 8V
1,5
Current (mA)
Current (A)
8
6
4
1,0
0,5
2
Vgs = 0V..6V
0
4
8
Voltage (V)
12
0
1000
2000
3000
4000
5000
Voltage (V)
Semikron switch: 8KV – 10A – 2 ohms
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Bipolar devices: 3500V-6500V
Wide band-gap Power Semiconductor Devices
SiC Bipolar-JFET
100
Gate
p Channel
+
p- Drift region
n-Collector
4H-SiC n+ Substrat
p+
T=25°C
T=150°C
80
n
2.4
2
p+
Current-Density (A/cm )
n
3.0
BIFET
Anode
70A/cm²
60
1.8
1.2
40
0.6
20
4kV JFET
0.0
0
Cathode
Current (A)
Anode
0
3
6
9
12
Voltage (V)
Carrier lifetime in p - epilayers has to be increased well above 1 µs to reduce
the forward voltage
Tail current turn-off behaviour shows a long relaxation time increasing with
temperature due to the not yet optimised gate control region.
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Wide band-gap Power Semiconductor Devices
Bipolar devices: 3500V-6500V
10kV SiC Power MOSFET
• State-of-the-art SiC power MOSFET [S-H. Ryu, et al., ISPSD’2006]
10 kV, 5 A 4H SiC power DMOSFET
− 100 µm thick n-type epilayer (6×1014 cm-3)
− Thermally grown gate oxide, NO annealed
− Peak effective channel mobility: 13 cm2/V.s
− Active area: 0.15 cm2
− Ron = 111 mΩ.cm2 @ RT and VG = 15 V
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Wide band-gap Power Semiconductor Devices
Bipolar devices: 3500V-6500V
SiC IGBT ???
Problems of MOSFETS (Channel mobility, reliability)
+ Problems of Bipolar (current gain, degradation (stacking faults)
+ Problems of highly doped P substrate growth
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Wide band-gap Power Semiconductor Devices
Bipolar devices: 3500V-6500V
SiC IGBT ???
Problems of MOSFETS (Channel mobility, reliability)
+ Problems of Bipolar (current gain, degradation (stacking faults)
+ Problems of highly doped P substrate growth
September 2006: CREE 10kV P-channel IGBT
•
•
•
3V + 20 mΩ x cm2
VF =3.9V at 10A instead of 4.4V for the VDMOS
Improvement of channel mobility and conductivity
modulation possible
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Wide band-gap Power Semiconductor Devices
Conclusions
Future Trends
Question was: Will SiC be useful for power electronics ?
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Wide band-gap Power Semiconductor Devices
Conclusions
Future Trends
Question was: Will SiC be useful for power electronics ?
Question is: When SiC will enter in power electronic ?
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Wide band-gap Power Semiconductor Devices
Conclusions
Future Trends
Question was: Will SiC be useful for power electronics ?
Question is: When SiC will enter in power electronic ?
Source: ECPE “Sic User Forum” march 2006 – Complete presentation available
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Conclusions
Wide band-gap Power Semiconductor Devices
Future Trends
Question was: Will SiC be useful for power electronics ?
Question is: When SiC will enter in power electronic ?
Expected roadmap: > 3.5 KV
1 cm2 10kV IGBT and PiN Diode chips affordable for
prototypes will be available by 2008
Production of degradation-free bipolar SiC devices by
2009
Stabilised production grade SiC devices available in 2010
Source: ECPE “Sic User Forum” march 2006 – Complete presentation available
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Wide band-gap Power Semiconductor Devices
Conclusions
Future Trends
SiC rectifiers
• Schottky and now JBS diodes are commercially available up to
1.2 kV.
• PiN diodes will be only relevant for BV over 3kV.
- Need to overcome its reliability problem (forward
voltage drift) before commercialisation
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Conclusions
Wide band-gap Power Semiconductor Devices
Future Trends
SiC Switches
• Commercialization of the cascode pair (a high-voltage,
normally-on SiC JFET + a low-voltage Si MOSFET).
• BJTs/Darlingtons are promising, they also suffer from
reliability problems.
• A normally-off SiC switch is expected. It could be the SiC
MOSFET (<5kV) or the SiC IGBT (>5kV).
• A normally-off SiC power transistor commercially available
within next two years in the BV range of 600V-1200V.
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Wide band-gap Power Semiconductor Devices
Conclusions
Future Trends
SiC MEMS
Higher young modulus (x3)
Higher yield strength (x3)
0.8um
3.2um
1um
150um
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Wide band-gap Power Semiconductor Devices
Conclusions
Future Trends
SiC advantages for biomedical devices
Biocompatibility – higher hardness – higher resistivity
transparency
6H-SiC
In-vivo measurement of impedance
and pH of tissues in organs
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Wide band-gap Power Semiconductor Devices
Conclusions
Conditions affecting the market volume for SiC power devices:
Technical advantages and realised device performance
Improved system efficiency by using SiC power devices
Higher device costs (mainly dominated by substrate costs)
New packaging development (material, technology & reliability)
Application of new circuit concepts
Silicon answers to the challenges of SiC (CoolMOS; Trench IGBT…)
The development of future power electronics with higher power
densities will cause an increasing market penetration of SiC power
devices.
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Wide band-gap Power Semiconductor Devices
ECSCRM 2008
7th European Conference
on Silicon Carbide and
Related Materials
Barcelona
September 7th – 11th 2008
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