power electronics chapter 2 power electronic devices
TRANSCRIPT
Power ElectronicsPower Electronics
Chapter 2
Power Electronic Devices
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OutlineOutline
2.1 An introductory overview of power electronic devices2.1 An introductory overview of power electronic devices
2.2 Uncontrolled device — power diode2.2 Uncontrolled device — power diode
2.3 Half-controlled device — thyristor2.3 Half-controlled device — thyristor
2.4 Typical fully-controlled devices2.4 Typical fully-controlled devices
2.5 Other new power electronic devices2.5 Other new power electronic devices
2.6 Power integrated circuits and integrated power 2.6 Power integrated circuits and integrated power
electronics moduleselectronics modules
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The concept and featuresThe concept and features
Configuration of systems using power electronic devicesConfiguration of systems using power electronic devices
ClassificationsClassifications
Major topicsMajor topics
2.1 An introductory overview of power 2.1 An introductory overview of power electronic devices electronic devices
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Power electronic devices:Power electronic devices:
In broad senseIn broad sense
Very often: Very often:
Major material used in power semiconductor devicesMajor material used in power semiconductor devices
—— Silicon—— Silicon
are the electronic devices that can be directly used in the power are the electronic devices that can be directly used in the power processing circuits to convert or control electric power.processing circuits to convert or control electric power.
The concept of power electronic devicesThe concept of power electronic devices
power electronic devicespower electronic devices
Vacuum devices: Mercury arc rVacuum devices: Mercury arc rectifier thyratron, etc. . ectifier thyratron, etc. . seldom in use todayseldom in use today
Semiconductor devices: Semiconductor devices: major power electronic devices major power electronic devices since late 1950ssince late 1950s
Power electronic devices = Power semiconductor devicesPower electronic devices = Power semiconductor devices
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Features of power electronic devicesFeatures of power electronic devices
The electric power that power electronic device The electric power that power electronic device deals with is usually much larger than that the deals with is usually much larger than that the information electronic device does.information electronic device does.
Usually working in switching states to reduce power Usually working in switching states to reduce power losseslosses
+ -v
ip=vi=0Off-state Current through the device is 0
i=0
p=vi=0On-state Voltage across the device is 0v=0
+ -v
i
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Features of power electronic devicesFeatures of power electronic devices
Need to be controlled by information electronic circuits.Need to be controlled by information electronic circuits.Very often, drive circuits are necessary to interface Very often, drive circuits are necessary to interface between information circuits and power circuits.between information circuits and power circuits.
Dissipated power loss usually larger than information Dissipated power loss usually larger than information electronic devices — special packaging and heat sink electronic devices — special packaging and heat sink are necessary.are necessary.
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Power losses on power semiconductor devicesPower losses on power semiconductor devices
On-state(conduction state)
turning-off
Off-state(blocking state)
turning-on
t
t
t
v
i
p
= conduction loss + turn-off loss + off-state loss + turn-on loss= conduction loss + turn-off loss + off-state loss + turn-on lossTotal power loss onTotal power loss on
a power semiconductor a power semiconductor devicedevice
Switching lossSwitching loss
(on-state loss)(on-state loss)
((usually very small usually very small and can be neglectedand can be neglected))
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Configuration of systems using power Configuration of systems using power electronic deviceselectronic devices
Co
ntro
l circuit
Detection(measurement)
circuit
drivecircuit
Power circuit(power stage,main circuit)
Control circuit (in a broad sense)
Power electronic system: Electric isolation:optical or magnetic
Protection circuit is also very often used in power electronic system especially for the expensive power semiconductors.
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Terminals of a power electronic deviceTerminals of a power electronic device
C
E
G
A power electronic device must have at least two terminals allowing power circuit current flow through.
A power electronic device usually has a third terminal ——control terminal to control the states of the device.
The control signal from drive circuit must be connected The control signal from drive circuit must be connected between the control terminal and a fixed power circuit between the control terminal and a fixed power circuit terminal (therefore called common terminal ).terminal (therefore called common terminal ).
Drive Circuit
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A classification of power electronic devicesA classification of power electronic devices
Uncontrolled device: diodeUncontrolled device: diode(Uncontrollable device)(Uncontrollable device)
Fully-controlled device: Power MOSFET, Fully-controlled device: Power MOSFET, IGBT,GTO, IGCT (Fully-controllable device)IGBT,GTO, IGCT (Fully-controllable device)
Half-controlled device: thyristorHalf-controlled device: thyristor(Half-controllable device)(Half-controllable device)
has only two terminals and can not be controlled by control signal. The on and off states of the device are determined by the power circuit.
is turned-on by a control signal and turned-off by the power circuit
The on and off states of the device are controlled by control signals.
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Other classificationsOther classifications
power electronic devicespower electronic devicesPulse-triggered devicesPulse-triggered devices
Level-sensitive (level-triggered) devicesLevel-sensitive (level-triggered) devices
power electronic devicespower electronic devices
power electronic devicespower electronic devicesCurrent-driven (current-controlled) devicesCurrent-driven (current-controlled) devices
Voltage-driven (voltage-controlled) devices Voltage-driven (voltage-controlled) devices (Field-controlled devices)(Field-controlled devices)
Unipolar devices (Majority carrier devices)Unipolar devices (Majority carrier devices)
Composite devicesComposite devices
Bipolar devices (Minority carrier devices)Bipolar devices (Minority carrier devices)
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Appearance, structure, and symbol Appearance, structure, and symbol
Physics of operationPhysics of operation
CharacteristicsCharacteristics
SpecificationSpecification
Special issuesSpecial issues
Devices of the same familyDevices of the same family
Major topics for each deviceMajor topics for each device
Switching characteristicsSwitching characteristics(Dynamic characteristics)(Dynamic characteristics)
Static characteristicsStatic characteristics
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Passive components in power electronic Passive components in power electronic circuitcircuit
Transformer, inductor, capacitor and resistorTransformer, inductor, capacitor and resistor These are called passive components in a These are called passive components in a power electronic circuit since they can not be power electronic circuit since they can not be controlled by control signal and their controlled by control signal and their characteristics are usually constant and linear.characteristics are usually constant and linear.
The requirements for these passive components The requirements for these passive components by power electronic circuits could be very different by power electronic circuits could be very different from those by ordinary circuits.from those by ordinary circuits.
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2.2 Uncontrolled device —Power diode2.2 Uncontrolled device —Power diode
AppearanceAppearance
StructureStructure SymbolSymbol
CathodeAnodeKKAA
Anode Cathode
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PN junctionPN junction
-。 -。 -。
-。 -。 -。
-。 -。 -。
-。 -。 -。
-。 -。 -。
+· +· +·
+· +· +·+· +· +·
+· +· +·+· +· +·
+-
+-
+-
+-
+-
p region n region
Direction ofinner electric field
Space charge region
(depletion region,potential barrier
region)
Semiconductor (Column IV element, Si)Semiconductor (Column IV element, Si) Electrons and holesElectrons and holes Pure semiconductor (intrinsic semiconductor)Pure semiconductor (intrinsic semiconductor) Doping, P-type semiconductor. N-type semiconductorDoping, P-type semiconductor. N-type semiconductor PN junctionPN junction Equilibrium of diffusion and driftEquilibrium of diffusion and drift
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PN junction with voltage applied in the PN junction with voltage applied in the forward directionforward direction
V
+
+
+
+
+
--
-
-
-
np
Wo
W+ -
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PN junction with voltage applied in the PN junction with voltage applied in the reverse directionreverse direction
+- V
+
+
+
+
+
--
-
-
-
-
-
-
+
+
+
np
Wo
W
Effective direction of electric field
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Construction of a practical power diodeConstruction of a practical power diode
Features different from low-power (information Features different from low-power (information electronic) diodeselectronic) diodes– – Larger size–– Vertically oriented structure–– n drift region (p-i-n diode)–– Conductivity modulation
250μm
Breakdown voltage dependent
10 μmp
Nd =10 cmn substrate -319
Na =10 cm-319+
n epi Nd =10 cm-314
p
Nd =10 cmn substrate -319+
Na =10 cm-319+
n epi-Nd =10 cm
-314
i
Anode
Cathode
+
-
V
-
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Forward-biased power diodeForward-biased power diode
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Reverse-biased power diodeReverse-biased power diode
BreakdownBreakdown –– Avalanche breakdown –– Thermal breakdown
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The positive and negative charge in the depletion The positive and negative charge in the depletion region is variable with the changing of external region is variable with the changing of external voltage.voltage.—–—–Junction capacitor CJunction capacitor CJJ . .
Junction capacitor CJunction capacitor CJJ
Junction capacitor influences the switching Junction capacitor influences the switching characteristics of power diode.characteristics of power diode.
Junction capacitorJunction capacitor
Diffusion capacitor Diffusion capacitor CCDD
Potential barrier capacitor Potential barrier capacitor CCBB
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Static characteristics of power diodeStatic characteristics of power diode
The I-V characteristics of power diode The I-V characteristics of power diode
I
O
IF
U TO U F U
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Switching (dynamic) characteristics Switching (dynamic) characteristics of power diodeof power diode
Reverse-recovery process:Reverse-recovery process:Reverse-recovery time, reverse-recovery charge, reverse-recovery peak current.
Turn-off transientTurn-off transient
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Switching (dynamic) characteristics Switching (dynamic) characteristics of power diodeof power diode
Forward recovery process:Forward recovery process: forward-recovery time
Turn-on transientTurn-on transient
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Specifications of power diodeSpecifications of power diode
Average rectified forward current IAverage rectified forward current IF(AV)F(AV)
Forward voltage UForward voltage UFF
Peak repetitive reverse voltage UPeak repetitive reverse voltage URRMRRM
Maximum junction temperature TMaximum junction temperature TJMJM
Reverse-recovery time tReverse-recovery time trrrr
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Types of power diodesTypes of power diodes
General purpose diode (rectifier diode):General purpose diode (rectifier diode):
Fast recovery diodeFast recovery diode
Schottky diode (Schottky barrier diode-SBD)Schottky diode (Schottky barrier diode-SBD)
standard recovery
Reverse recovery time and charge specified. trr is usually less than 1μs, for many less than 100 ns —— ultra-fast recovery diode.
– A majority carrier device– Essentially no recovered charge, and lower forward voltage.– Restricted to low reverse voltage and blocking capability
(less than 200V)
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Examples of commercial power diodesExamples of commercial power diodes
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History and applications of power diodeHistory and applications of power diode
Applied in industries starting 1950sApplied in industries starting 1950s
Still in-use today. Usually working with controlled devicStill in-use today. Usually working with controlled devices as necessary componentses as necessary components
In many circumstances fast recovery diodes or schottkIn many circumstances fast recovery diodes or schottky diodes have to be used instead of general purpose dy diodes have to be used instead of general purpose diodes.iodes.
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2.3 Half-controlled device—Thyristor2.3 Half-controlled device—Thyristor
Another name: SCR—silicon controlled rectifierAnother name: SCR—silicon controlled rectifier
Thyristor Opened the power electronics eraThyristor Opened the power electronics era– 1956, invention, Bell Laboratories1956, invention, Bell Laboratories– 1957, development of the 1st product, GE1957, development of the 1st product, GE– 1958, 1st commercialized product, GE1958, 1st commercialized product, GE– Thyristor replaced vacuum devices in almost every power Thyristor replaced vacuum devices in almost every power
processing area.processing area.
Still in use in very high power situation. Thyristor still Still in use in very high power situation. Thyristor still has the highest power-handling capability. has the highest power-handling capability.
HistoryHistory
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Appearance and symbol of thyristorAppearance and symbol of thyristor
SymbolSymbolAppearanceAppearance
KG
A
CathodeCathode
AnodeAnode
GateGate
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Structure and equivalent circuit of thyristorStructure and equivalent circuit of thyristor
• StructureStructure • Equivalent circuitEquivalent circuit
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Physics of thyristor operationPhysics of thyristor operation
Equivalent circuit: A pnp transiEquivalent circuit: A pnp transi
stor and an npn transistor intercstor and an npn transistor interc
onnected together.onnected together.
Positive feedbackPositive feedback
TriggerTrigger
Can not be turned off by control Can not be turned off by control
signalsignal
Half-controllableHalf-controllable
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Quantitative description of thyristor operationQuantitative description of thyristor operation
IIc1c1==11 I IAA + + I ICBO1CBO1 （（ 2-12-1））
IIc2c2==22 I IKK + + I ICBO2CBO2 （（ 2-22-2））
IIKK==IIAA++IIG G （（ 2-32-3））
IIAA==IIcc11++IIcc2 2 （（ 2-42-4））
)(1 21
CBO2CBO1G2A
IIII （（ 2-2-
55））
When IWhen IGG=0, =0, is small.is small.
When IWhen IGG>0, >0, will approach 1, and I will approach 1, and IAA will be very large. will be very large.
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Other methods to trigger thyristor Other methods to trigger thyristor
High voltage across anode and cathode— avalanchHigh voltage across anode and cathode— avalanche breakdowne breakdown
High rising rate of anode voltage — du/dt too highHigh rising rate of anode voltage — du/dt too high
High junction temperatureHigh junction temperature
Light activationLight activation
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Static characteristics of thyristorStatic characteristics of thyristor
Blocking when reverse Blocking when reverse biased, no matter if there biased, no matter if there is gate current appliedis gate current applied
Conducting only when Conducting only when forward biased and there forward biased and there is triggering current is triggering current applied to the gateapplied to the gate
Once triggered on, will be Once triggered on, will be latched on conducting latched on conducting even when the gate even when the gate current is no longer current is no longer applied applied
Turning off: decreasing Turning off: decreasing current to be near zero current to be near zero with the effect of external with the effect of external power circuitpower circuit
Gate I-V characteristicsGate I-V characteristics
O UAk
IA
IH
IG2
IG1
IG=0
Ubo
UDSM
UDRM
URRM
URSM
forward forward conductingconducting
avalanche avalanche breakdownbreakdown
reverse reverse blockingblocking
increasing IG
forward forward blockingblocking
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Switching characteristics of thyristorSwitching characteristics of thyristor
Turn-on transientTurn-on transient– Delay time tDelay time tdd
– Rise time tRise time trr
– Turn-on time tTurn-on time tgtgt
Turn-off transient Turn-off transient – Reverse recovery Reverse recovery
time ttime trrrr
– Forward recovery Forward recovery time ttime tgrgr
– Turn-off time tTurn-off time tqq
100%90%
10%
u AK
t
tO
0 td t r
t rr tgrU RRM
IRM
iA
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Specifications of thyristorSpecifications of thyristor
Peak repetitive forward blocking voltage UPeak repetitive forward blocking voltage UDRMDRM
Peak repetitive reverse blocking voltage UPeak repetitive reverse blocking voltage URRMRRM
Peak on-state voltage UPeak on-state voltage UTMTM
Average on-state current IAverage on-state current IT(AV)T(AV)
Holding current IHolding current IHH
Latching up current ILatching up current ILL
Peak forward surge current IPeak forward surge current ITSMTSM
du/dtdu/dt
di/dtdi/dt
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The family of thyristorsThe family of thyristors
Fast switching thyristor—FSTFast switching thyristor—FSTTriode AC switch—TRIAC Triode AC switch—TRIAC (Bi-directional triode thyristor)(Bi-directional triode thyristor)
Reverse-conducting thyristor Light-triggered (activited) thyristorReverse-conducting thyristor Light-triggered (activited) thyristor — —RCT —LTTRCT —LTT
KG
A
A
G
K
G
K
A
G
T1
T2
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2.4 Typical fully-controlled devices2.4 Typical fully-controlled devices2.4.1 Gate-turn-off thyristor —GTO2.4.1 Gate-turn-off thyristor —GTO
2.4.2 Giant transistor —GTR2.4.2 Giant transistor —GTR
2.4.3 Power metal-oxide-semiconductor field effect 2.4.3 Power metal-oxide-semiconductor field effect transistor — Power MOSFET transistor — Power MOSFET
2.4.4 Insulated-gate bipolar transistor —IGBT2.4.4 Insulated-gate bipolar transistor —IGBT
FeaturesFeatures
– Begin to be used in large amount in 1980sBegin to be used in large amount in 1980s– GTR is obsolete and GTO is also seldom used today. GTR is obsolete and GTO is also seldom used today. – IGBT and power MOSFET are the two major power IGBT and power MOSFET are the two major power semiconductor devices nowadays. semiconductor devices nowadays.
ApplicationsApplications– IC fabrication technology, fully-controllable, high frequencyIC fabrication technology, fully-controllable, high frequency
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A
G K G GK
N1
P1
N2N2 P2
b)a)
2.4.1 Gate-turn-off thyristor—GTO2.4.1 Gate-turn-off thyristor—GTO
Major difference from conventional thyristor:Major difference from conventional thyristor:
The gate and cathode structures are highly integrated, The gate and cathode structures are highly integrated, with various types of geometric forms being used to layout with various types of geometric forms being used to layout the gates and cathodes.the gates and cathodes.
StructureStructure SymbolSymbol
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Physics of GTO operationPhysics of GTO operationThe basic operation of GTO The basic operation of GTO is the same as that of the is the same as that of the conventional thyristor. conventional thyristor.
The principal differences lie The principal differences lie in the modifications in the in the modifications in the structure to achieve gate structure to achieve gate turn-off capability.turn-off capability.
– Large Large 22
– 11++22 is just a little larger is just a little larger than the critical value 1. than the critical value 1.
– Short distance from gate Short distance from gate to cathode makes it to cathode makes it possible to drive current possible to drive current out of gate.out of gate.
R
NPN
PNP
A
G
S
K
EG
IG
EAIK
Ic2Ic1
IA
V1
V2
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Characteristics of GTOCharacteristics of GTO
Static characteristicsStatic characteristics– Identical to conventional thyristor in the forward directionIdentical to conventional thyristor in the forward direction– Rather low reverse breakdown voltage (20-30V)Rather low reverse breakdown voltage (20-30V)
Switching characteristicsSwitching characteristics
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Specifications of GTOSpecifications of GTO
Most GTO specifications have the same meanings Most GTO specifications have the same meanings as those of conventional thyristor.as those of conventional thyristor.
Specifications different from thyristor’sSpecifications different from thyristor’s– Maximum controllable anode current IMaximum controllable anode current IATOATO
– Current turn-off gain Current turn-off gain ββoffoff
– Turn-on time tTurn-on time tonon
– Turn-off time tTurn-off time toffoff
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2.4.2 Giant Transistor—GTR2.4.2 Giant Transistor—GTR
GTR is actually the bipolar junction transistor that GTR is actually the bipolar junction transistor that can handle high voltage and large current. can handle high voltage and large current.
So GTR is also called power BJT, or just BJT.So GTR is also called power BJT, or just BJT.
Basic structureBasic structureSymbolSymbol
b
e
c
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Structure of GTR——different from its Structure of GTR——different from its information-processing counterpartinformation-processing counterpart
Multiple-emitter structureMultiple-emitter structure Darlington configurationDarlington configuration
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Physics of GTR operationPhysics of GTR operation
Same as information BJT deviceSame as information BJT device
holes
electronsEb
Ec
ib
ic=ib
ie=(1+ib
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Static characteristics of GTRStatic characteristics of GTR
cut-off region
Amplifying (active) region
O
I
ib3
ib2
ib1ib1<ib2<ib3
Uce
Sat
urat
ion
regi
on
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Switching characteristics of GTRSwitching characteristics of GTR
Turn-on transientTurn-on transient– Turn-on delay time tTurn-on delay time tdd
– Rise time tRise time trr
– Turn-on time tTurn-on time tonon
Turn-off transientTurn-off transient– Storage time tStorage time tss
– Falling time tFalling time tff
– Turn-off timeTurn-off time t toffoff
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Second breakdown of GTRSecond breakdown of GTR
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Safe operating area (SOA) of GTRSafe operating area (SOA) of GTR
SOA
O
Ic
IcMPSB
PcM
UceUceM
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2.4.3 Power metal-oxide-semiconductor field 2.4.3 Power metal-oxide-semiconductor field effect transistor—Power MOSFETeffect transistor—Power MOSFET
Basic structureBasic structure SymbolSymbol
G
S
D
P channel
A classification A classification
Field Effect Field Effect
TransistorTransistor (FET) (FET)
Metal-oxide-semiconductor FET (MOSFET)Metal-oxide-semiconductor FET (MOSFET) Power MOSFETPower MOSFET
Junction FET (JFET)Junction FET (JFET) Static induction transistor (SIT)Static induction transistor (SIT)
n channeln channelp channelp channel
G
S
D
N channel
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Structures of power MOSFETStructures of power MOSFET
Vertical structureVertical structure—VMOS—VMOS– VVMOS, VDMOSVVMOS, VDMOS
Multiple parallel cellsMultiple parallel cells– Polygon-shaped cellsPolygon-shaped cells
A structure of hexagon cellsA structure of hexagon cells
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Physics of MOSFET operationPhysics of MOSFET operation
p-n- junction is reverse-biased
off-state voltage
appears across n- region
Off-stateOff-state
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Physics of MOSFET operationPhysics of MOSFET operation
p- n- junction is slightly reverse biasedpositive gate voltage induces conducting channeldrain current flows through n- region and conducting channelon resistance = total resistances of n- region, conducting channel,source and drain contacts, etc.
On-stateOn-state
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Static characteristics of power MOSFETStatic characteristics of power MOSFET
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Switching characteristics of power MOSFETSwitching characteristics of power MOSFET
Turn-on transientTurn-on transient– Turn-on delay time tTurn-on delay time td(on)d(on)
– Current rising time tCurrent rising time triri
– Voltage falling time tVoltage falling time tfvfv
Turn-off transientTurn-off transient– Turn-off delay time tTurn-off delay time td(off)d(off)
– Voltage rising time tVoltage rising time trvrv
– Current falling time tCurrent falling time tfifi
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Miller capacitance and Miller plateauMiller capacitance and Miller plateau
Waveform details and length of Waveform details and length of time intervals will be dependent time intervals will be dependent on the power circuit topology, on the power circuit topology, control, snubber circuit and the control, snubber circuit and the parasitic of the power circuit.parasitic of the power circuit.
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Specifications of power MOSFETSpecifications of power MOSFET
Drain-source breakdown voltage UDrain-source breakdown voltage UDSDS
Continuous drain current IContinuous drain current IDD
Peak pulsed drain current IPeak pulsed drain current IDMDM
On (On-state) resistance ROn (On-state) resistance RDS(on)DS(on)
Inter-terminal capacitancesInter-terminal capacitances– – Short circuit input capacitance Short circuit input capacitance CCississ== C CGSGS++ C CGDGD
– – Reverse transfer capacitance Reverse transfer capacitance CCrssrss== C CGDGD
– – Short circuit output capacitance Short circuit output capacitance CCossoss== C CDSDS++ C CGDGD SOA of power MOSFETSOA of power MOSFET–– No second breakdownNo second breakdown
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Examples of commercial power MOSFETExamples of commercial power MOSFET
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Features and applications of power MOSFETFeatures and applications of power MOSFET
Voltage-driven device, simple drive circuitVoltage-driven device, simple drive circuit
Majority-carrier device, fast switching speed, high Majority-carrier device, fast switching speed, high operating frequency (could be hundreds of kHz)operating frequency (could be hundreds of kHz)
Majority-carrier device, better thermal stabilityMajority-carrier device, better thermal stability
On-resistance increases rapidly with rated blocking On-resistance increases rapidly with rated blocking voltagevoltage– Usually used at voltages less than 600V and power less Usually used at voltages less than 600V and power less
than 10kWthan 10kW– 1000V devices are available, but are useful only at low 1000V devices are available, but are useful only at low
power levels(100W)power levels(100W)
Part number is selected on the basis of on-Part number is selected on the basis of on-resistance rather than current ratingresistance rather than current rating
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The body diode of power MOSFETThe body diode of power MOSFET
The body diodeThe body diode Equivalent circuitEquivalent circuit
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2.4.4 Insulated-gate bipolar transistor 2.4.4 Insulated-gate bipolar transistor —IGBT—IGBT
FeaturesFeatures• On-state losses are much smaller than those of a power On-state losses are much smaller than those of a power
MOSFET, and are comparable with those of a GTRMOSFET, and are comparable with those of a GTR• Easy to drive —similar to power MOSFETEasy to drive —similar to power MOSFET• Faster than GTR, but slower than power MOSFETFaster than GTR, but slower than power MOSFET
ApplicationApplication• The device of choice in 500-4500V applications, at power The device of choice in 500-4500V applications, at power
levels of several kW to several MWlevels of several kW to several MW
Combination of MOSFET and GTRCombination of MOSFET and GTR
GTRGTR: low conduction losses (especially at larger blocking voltages),: low conduction losses (especially at larger blocking voltages),
longer switching times, current-drivenlonger switching times, current-driven
MOSFETMOSFET: faster switching speed, easy to drive (voltage-driven),: faster switching speed, easy to drive (voltage-driven),
larger conduction losses (especially for higher blocking voltages)larger conduction losses (especially for higher blocking voltages)
IGBTIGBT
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Structure and operation principle of IGBTStructure and operation principle of IGBT
Basic structureBasic structure Multiple cell structureMultiple cell structure
Basic structure similar to Basic structure similar to power MOSFET, except power MOSFET, except extra p regionextra p region
On-state: minority carriers On-state: minority carriers are injected into drift region, are injected into drift region, leading to conductivity leading to conductivity modulationmodulation
compared with power compared with power MOSFET: slower switching MOSFET: slower switching times, lower on-resistance times, lower on-resistance useful at higher voltages useful at higher voltages (up to 4500V)(up to 4500V)
E G
C
N +
N -
a )
PN + N +
PN + N +
P +
Em itter G ate
Collector
In jecting layer
Buffer layerDrift regionJ 3 J 2
J 1
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Equivalent circuit and circuit symbol of IGBTEquivalent circuit and circuit symbol of IGBT
Equivalent circuitEquivalent circuit Circuit symbolCircuit symbol
G
E
C
+
-
+-
+
-
ID R N
IC
V J1
ID R o n
D rift reg ionresistance
G
C
E
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Static characteristics of IGBTStatic characteristics of IGBT
O
Active region
Cut-off (forwardblocking) region
Saturation region(O n region)
Reverseblocking region
IC
U R M
U F M U C E
U G E (th )
U G E
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Switching characteristics of IGBTSwitching characteristics of IGBT
IGBT turn-on is similar to power MOSFET turn-on
The major difference between IGBT turn-off and power MOSFET turn-off:– There is current
tailing in the IGBT turn-off due to the stored charge in the drift region.
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Parasitic thyristor and latch-up in IGBTParasitic thyristor and latch-up in IGBT
Main current path pnp transistor and the parasitic npMain current path pnp transistor and the parasitic npn transistor compose a parasitic thyristor inside IGBT.n transistor compose a parasitic thyristor inside IGBT.High emitter current tends to latch the parasitic thyrisHigh emitter current tends to latch the parasitic thyristor on.tor on.Modern IGBTs are essentially latch-up proofModern IGBTs are essentially latch-up proof
Location of equivalent devicesLocation of equivalent devices Complete IGBT equivalent circuitComplete IGBT equivalent circuit
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Specifications of IGBTSpecifications of IGBT
Collector-emitter breakdown voltage UCollector-emitter breakdown voltage UCESCES
Continuous collector current IContinuous collector current ICC
Peak pulsed collector current IPeak pulsed collector current ICMCM
Maximum power dissipation PMaximum power dissipation PCMCM
Other issues:Other issues:
SOA of IGBTSOA of IGBT– The IGBT has a rectangular SOA with similar shape to the The IGBT has a rectangular SOA with similar shape to the
power MOSFET.power MOSFET.
Usually fabricated with an anti-parallel fast diodeUsually fabricated with an anti-parallel fast diode
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Examples of commercial IGBTExamples of commercial IGBT
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2.5 Other new power electronic devices2.5 Other new power electronic devices
Static induction transistor —SITStatic induction transistor —SIT
Static induction thyristor —SITHStatic induction thyristor —SITH
MOS controlled thyristor — MCTMOS controlled thyristor — MCT
Integrated gate-commutated thyristor —IGCTIntegrated gate-commutated thyristor —IGCT
Power electronic devices based on wide band gap sPower electronic devices based on wide band gap semiconductor materialemiconductor material
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Static induction transistorStatic induction transistor—SIT—SIT
Another name: power junction field effect transistorAnother name: power junction field effect transistor—power JFET—power JFET
FeaturesFeatures– Majority-carrier deviceMajority-carrier device– Fast switching, comparable to power MOSFETFast switching, comparable to power MOSFET– Higher power-handling capability than power MOSFETHigher power-handling capability than power MOSFET– Higher conduction losses than power MOSFETHigher conduction losses than power MOSFET– Normally-on device, not convenient (could be made Normally-on device, not convenient (could be made
normally-off but with even higher on-state losses)normally-off but with even higher on-state losses)
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Static induction thyristorStatic induction thyristor—SITH—SITH
other namesother names– Field controlled thyristorField controlled thyristor—FCT—FCT– Field controlled diodeField controlled diode
FeaturesFeatures– Minority-carrier device, a JFET structure with an additional Minority-carrier device, a JFET structure with an additional
injecting layerinjecting layer– Power-handling capability similar to GTOPower-handling capability similar to GTO– Faster switching speeds than GTOFaster switching speeds than GTO– Normally-on device, not convenient (could be made Normally-on device, not convenient (could be made
normally-off but with even higher on-state losses)normally-off but with even higher on-state losses)
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MOS controlled thyristorMOS controlled thyristor—MCT—MCT
Essentially a GTO with integrated MOS-driven Essentially a GTO with integrated MOS-driven gates controlling both turn-on and turn-off that gates controlling both turn-on and turn-off that potentially will significantly simplify the design of potentially will significantly simplify the design of circuits using GTO.circuits using GTO.
The difficulty is how to design a MCT that can be The difficulty is how to design a MCT that can be turned on and turned off equally well. turned on and turned off equally well.
Once believed as the most promising device, but Once believed as the most promising device, but still not commercialized in a large scale. The future still not commercialized in a large scale. The future remains uncertain. remains uncertain.
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Integrated gate-commutated thyristor Integrated gate-commutated thyristor — IGCT— IGCT
Introduced in 1997 by ABBIntroduced in 1997 by ABB
Actually the close packaging of GTO and the gate dActually the close packaging of GTO and the gate drive circuit with multiple MOSFETs in parallel providirive circuit with multiple MOSFETs in parallel providing the gate currentsng the gate currents
Short name: GCTShort name: GCT
Conduction drop, gate driver loss, and switching spConduction drop, gate driver loss, and switching speed are superior to GTOeed are superior to GTO
Competing with IGBT and other new devices to replCompeting with IGBT and other new devices to replace GTO ace GTO
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Power electronic devices based on wide Power electronic devices based on wide band-gap semiconductor materialband-gap semiconductor material
Energy band and band gapEnergy band and band gap
Energy levels of an independent atom( left ) and energy Energy levels of an independent atom( left ) and energy bands of an atom in a crystal structurebands of an atom in a crystal structure
Band gap
E4
E3
E2
E1
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Properties of semiconductor materials Properties of semiconductor materials with potential for power deviceswith potential for power devices
SiSi GaAsGaAs GaPGaP 2H-GaN2H-GaN AINAIN 3C-SiC3C-SiC 4H-SiC4H-SiC 6H-SiC6H-SiC DiamondDiamond
Band gap Band gap at 300K(eV)at 300K(eV)
1.121.12 1.431.43 2.262.26 3.443.44 6.286.28 2.362.36 3.263.26 3.13.1 5.455.45
Relative Relative dielectric dielectric constantconstant
11.811.8 12.812.8 11.111.1 9.59.5 8.58.5 9.69.6 10.310.3 10.310.3 5.55.5
Breakdown Breakdown electric field electric field ( )( )
0.30.3 0.40.4 1.31.3 3.33.3 1212 1.21.2 2.02.0 2.42.4 1010
Electron Electron mobility at mobility at 300K 300K ( )( )
13501350 85008500 350350 900900 300300 900900 720720 370370 22002200
Maximum Maximum operating operating temperaturtemperature (K)e (K)
300300 460460 873873 12401240 11001100
Melting Melting temperaturtemperaturee( ) ( )
14151415 12381238 SublimeSublime>>1800>>1800
SublimeSublime>>1800>>1800
Phase Phase changechange
610 /V cm
2 /cm V S
C
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Physical Properties of Silicon Carbide
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Wafer Production
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Infineon SiC overview
Unipolar devices
Existing products:
¬ Diode based: 300V …1200V (1700V can be realized on demand)
Under development:
¬ JFET based: 600V …1500V (discrete, cascodes in modules)
¬ Expansion to higher voltage classes (single chip / super-cascode) possible
Bipolar devices
No development activities at IFX
Solid volume forecasts and cost targets required
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GaN and diamondGaN and diamond
GaN has much more potential than SiC to achieve higher switcGaN has much more potential than SiC to achieve higher switching frequency. hing frequency.
Manufacturing of single crystal GaN material is still unsolved. Manufacturing of single crystal GaN material is still unsolved. But fabrication techniques of GaN devices based on substrateBut fabrication techniques of GaN devices based on substrates of other crystal material have major break enough in recent ys of other crystal material have major break enough in recent years.ears.
Commercialized GaN SBD has been available since 2007 and Commercialized GaN SBD has been available since 2007 and GaN MOSFET has been reported frequently by recent technicGaN MOSFET has been reported frequently by recent technical papers.al papers.
Diamond is the material with the greatest potential for power dDiamond is the material with the greatest potential for power devices.evices.
The state of diamond device technology is primitive compared The state of diamond device technology is primitive compared to that of SiC and GaN. The method of fabricating single crystto that of SiC and GaN. The method of fabricating single crystal wafer and the technique for doing selective diffusion of impal wafer and the technique for doing selective diffusion of impurities and selective etching are still major obstacles.urities and selective etching are still major obstacles.
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2.6 2.6 Power integrated circuit and power Power integrated circuit and power modulemodule
Integrationof power electronic devices
Monolithic integration:Monolithic integration: power integrated circuitpower integrated circuit
Packaging integration: Packaging integration: power modulepower module
Smart power integrated circuit (Smart power IC, SPIC, Smart switch)
High voltage integrated circuit (HVIC)
Ordinary power module:just power devices packaged together
Integrated power electronics Module(IPEM): power devices, drive circuit, protection circuit, control circuit
Intelligent power module (IPM):power devices, drive circuit, protection circuit
(Lateral high-voltage devices fabricated with conventional logic-level devices)
(Vertical power devices onto which additional components are added without changing the vertical power devices process sequence)
For a high power equipment, more than one module may be needed, in which case the modules are also called Power electronics building blocks (PEBB)
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Three major challenges to integrationThree major challenges to integration– Electrical isolation of high-voltage components frElectrical isolation of high-voltage components fr
om low-voltage componentsom low-voltage components– Thermal management—power devices usually at Thermal management—power devices usually at
higher temperatures than low-voltage deviceshigher temperatures than low-voltage devices– Electro-magnetic interference (EMI) of power cirElectro-magnetic interference (EMI) of power cir
cuit to information circuitcuit to information circuit
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Review of device classificationsReview of device classifications
power electronicpower electronicdevicesdevices
Pulse-triggered devices: thyristor, GTO Pulse-triggered devices: thyristor, GTO
Level-sensitive (Level-triggered) devices: Level-sensitive (Level-triggered) devices: GTR,power MOSFET, IGBT, SIT, SITH, GTR,power MOSFET, IGBT, SIT, SITH, MCT, IGCTMCT, IGCT
power electronicpower electronicdevicesdevices
power electronicpower electronicdevicesdevices
Current-driven (current-controlled) devices:Current-driven (current-controlled) devices: thyristor, GTO, GTR
Voltage-driven (voltage-controlled) devices Voltage-driven (voltage-controlled) devices (Field-controlled devices):power MOSFET, (Field-controlled devices):power MOSFET, IGBT, SIT, SITH, MCT, IGCTIGBT, SIT, SITH, MCT, IGCT
Uni-polar devices (Majority carrier devices): Uni-polar devices (Majority carrier devices): SBD, power MOSFET, SITSBD, power MOSFET, SIT
Composite devices: IGBT, SITH, MCTComposite devices: IGBT, SITH, MCT
Bipolar devices (MinorityBipolar devices (Minority carrier devices): carrier devices): ordinary power diode, thyristor, GTO, GTR, ordinary power diode, thyristor, GTO, GTR, IGCT, IGBT, SITH, MCTIGCT, IGBT, SITH, MCT
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Comparison of the major types of devicesComparison of the major types of devices
Power-handling capabilityPower-handling capability
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Comparison of the major types of devicesComparison of the major types of devices
Maximum allowed current density as a function of Maximum allowed current density as a function of the switching frequencythe switching frequency
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Resistance distribution of MOSFETResistance distribution of MOSFET
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Roadmap of HV MOSFETRoadmap of HV MOSFET
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Super Junction TheoremSuper Junction Theorem
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Donor and acceptor space charges cancel each other out!
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Trench technologyTrench technology
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Package contribution to Rds(on) for Best-in-Class LV MOSFET devices
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Package development
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Vertical IGBT conceptsVertical IGBT concepts
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Summary of major devicesSummary of major devices
Power MOSFET ( for power level less than 10KW)Power MOSFET ( for power level less than 10KW)
IGBT ( for power level from several KW up to 10 IGBT ( for power level from several KW up to 10 MW)MW)
Thyristor ( for power level higher than 10MW )Thyristor ( for power level higher than 10MW )
Devices based on wide band-gap materials are Devices based on wide band-gap materials are very promisingvery promising