The Status of GaN-on-Si based Power Device Development at

The Status of GaN-on-Si based
Power Device Development at
International Rectifier
Michael A. Briere
ACOO Enterprises LLC
Under contract to International Rectifier
APEC Exhibitor Presentation
March 19, 2013
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1
What limits adoption rate of new power devices ?
First: If quality, reliability and robustness is not provided :
THERE IS NO PRODUCT only a Science project – NO MARKET SHARE
The governing metric for market adoption is : performance / cost (P/C)
For power electronic systems : P/C = efficiency*density/cost
This translates for power semiconductor devices as:
P/C = Conduction loss* Switching Loss / cost
If P/C ratio to incumbant ≤ 1, NICHE MARKET, SAM < 2-5 % of TAM
IF P/C ratio to incumbant > 2-3 x, widespread adoption, SAM > 80 % of TAM
About $ 4 B between 20 and 40 V ( mostly electronic dc-dc power supply )
About $ 6 B between 400 and 900 V ( mostly inverters and motor drives)
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2
Requirements for commercially viable 600 V GaNpowIR® devices :
 Epi + substrate cost < $3/ cm2 (i.e. silicon)
 I leak < 0.1 µA / mm , Ion / Ioff > 106
 Robust gate control ( established interface, Vth > 4 V)
Stable electrical performance (eg: RDS(on), R*Qg, Isat, Vp, Ileak )
 > 5000 hrs
 Large diameter ( > 150 mm) substrates with < 50 µm bow after epi
growth on standard thickness substrates – truly crack free epi
 Yields >80% for 10mm2 devices
 High Volume ( > 10 k wafers/ wk) Si Wafer Fab Compatible
 Supply needed: >106 150 mm wafer equivalents (to support 10% total
power semiconductor market at current utilization rates)
 Performance/Cost (GaN) > 2-3 x Performance/Cost (Si)
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3
Dielectric Breakdown of 600 V rated device > 1000 V.
Wg > 100 mm
10 nA/mm
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4
GaN cascode switch Blocking voltage
Blocking
VGS = 0V
1E-5
ID/WGA
(A/mm)
I drain
/ mm
8E-6
6E-6
25°C
150°C
4E-6
2E-6
0E+0
0
200
400
600
800
1000
VDS (V)
GaN device shows leakage determined breakdown (not an avalanche
breakdown)
At VDS = 600V, the typical drain leakages of HV GaN cascodes at
 25 oC: < 50 nA/mm
 150 oC: < 400 nA/mm
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Large area ( AA =8 mm2) 600 V rated cascoded device Current Capability
Output, 25C
Ion/Off(600 V) > 107
90
900 A/cm2
80
250 mA/mm
15V
70
I D (A)
60
8V
50
7.5V
40
7V
30
20
6.5V
10
0
0
2
4
6
8
10
12
VDS (V)
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6
HV Cascoded GaN switch: A powerful Circuit
D
Depletion mode GaN
G
S
Enhancement mode Si
Cascoded Switch
Leverages > 30 years of reliable drive experience
• Normally Off operation
• Gate drive compatible with existing Silicon solutions: +/-10V, +/- 15V , etc.
• Vgs(th) set by low voltage Si FET:
• Select Vt (3 V vs SJ, 5 V vs. IGBT), high enough to avoid C*dV/dt induced turn on
• Anti-parallel diode included: much lower reverse recovery than Si switches
• Minimal compromise in GaN HEMT performance
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7
Large area ( AA =8 mm2) 600 V rated cascoded device Current Capability
Transfer
100
ID (A)
10
150C
25C
1
0.1
0.01
0
1
2
3
4
5
6
7
8
9
10
VGS (V)
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8
600V GaN Device Stability - Improvements
Ratio of Rds(on) post/Rds(on) pre stress
2.5
2007
May
2010
2.0
August 2010
1.5
Nov 2010
1.0
0
100
200
300
350
400
500
550
Voltage
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No Evidence of Inverse Piezo-Electric Effect in GaNpowIRTM devices
•TEM Image ( No physical damage) from stress :
•HTRB ( Vd=26 V, Vg=-14 V at 150 C ) > 3000 Hours.
•HTRB ( Vd=26 V, Vg=-7V at 175 C) > 3000 hrs
•HTRB (Vd = 34 V, Vg=-22V at 150 C) > 600 hrs
•HTGB of -50 V for > 3000 hrs
•Foward conduction (I=200 mA/mm, Vd= 25 V)
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10
> 9000 hrs/device on HTRB : 30 V discrete HEMTs
11814-1-HTRB
IGSS @ -7.5V VGSS
80.0E-9
IGSS in Amps
70.0E-9
60.0E-9
50.0E-9
40.0E-9
30.0E-9
20.0E-9
Test Hours
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11
IR 600 V GaNpowIR® Gate Dielectric Reliability
MTTF at 150 C and Vg = - 20 V : > 10 8 hours
Vg = -50 V
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12
Reliability of IR 600V GaN Devices
•
IR 600V GaN devices are inherently reliable
•
Source-drain resistance, Rdson of 600 V rated cascode switch for a population
of representative cascoded GaN-on-Si based HEMT devices with Wg = 120 mm,
under a drain bias of 480 V and 0 gate bias for 5000 hrs at 150 C.
13
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Rectifier. All Rights Reserved.
13
Reliability of IR 600V GaN Devices
IDSS (Amperes/ mm of Wg) Vds = 500V
1.0E‐6
100 nA/mm
1.0E‐7
1.0E‐8
1.0E‐9
PRE
168hr 500hr 1000hr 2000hr 3000hr 4000hr 5000hr
Time Source to drain leakage, Idss, current measured with 500 V drain bias on 600 V
rated cascode switch for a population of representative devices with Wg = 120 mm,
under a drain bias of 480 V for 5000 hrs at 150 C.
14
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Rectifier. All Rights Reserved.
14
600 V Cascode device – step stress at 650 V for > 72 hours
650 V stress
>72 hours
Wg > 100 mm
Id-s < 10 nA/mm
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15
Robust 600 V GaN cascode switch in PFC circuit
Vout = 550V, Iout = 0.6A, unnoticeable Rdson shift after 18 hours, 100 kHz
Vds 18th hour
Vds 1st min
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16
Scalable III-N on Si Technology – IR’s GaNpowIR® : Lower Cost
Compositionally Graded III-N Transition Layer(s), eg. X > Y > Z
III-N Device Layers
• IR’s III-N epi IP portfolio
(as of March 2012)
• 17 issued US patents
……..
(2000-2010)
AlzGa(1-z)N
• 10 issued outside US
patents
• 8 published pending US
patents
• 19 Unpublished US
Apps
• 5 Licensed
Patents/Pend.
III-N Buffer Layer
AlyGa(1-y)N
AlxGa(1-x)N
Nucleation and Intermediate layer(s)
Silicon Based Substrate
Copyright 2012.
2013. International Rectifier. All Rights Reserved.
17
Wafer Distortion maps 2 um epi - Reactor 4
6” (625 um)
Warp < 20 um,
Bow -7 +/- 10 um
8” (725 um)
Warp < 40 um,
Bow 12 +/- 10 um
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2013. International Rectifier. All Rights Reserved.
18
Yield and Bin Pareto
90
87.3
81.7
81.9
80
80.8
78.4
Yield
76.1
Die size = 10.7mm2
70
67.2
60
14
16
19
20
21
24
Wafer Number
40
30
y
11
20
10
5
10
15
20
25
30
35
40
x
Green is good!!
19
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Rectifier. All Rights Reserved.
19
Gold Free Contact Resistance- lower cost
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20
Performance FOM (V-uJ, 25C)
600 V Switch Performance vs. Current Density
Best in
class
IGBT
1000
900
800
700
600
500
400
IR GaN
Prototypes
300
200
100
0
0
0.5
1
1.5
2
2.5
Current Density (A/mm^2)
Performance FOM: Vds(on) * (Eon + Eoff)
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2121
GaN has 4x lower Power Dissipation
3-ph Inverter Losses
12
GaN Motor Drive has 6 x lower
conduction losses and 2 x lower
switching losses
Loss (W)
8
4
Switching Loss (6kHz)
GaN
GaN
Conduction Loss (25C)
IRAM (IGBT)
6A
IRAM 6A
0
Test Condition:
IC = 1.5A
Vbus = 300V
Output voltage = 160V
Output Power = 415W
Tc=150C
22
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Rectifier. All Rights Reserved.
22
3-4x Lower Losses in 1/10th the Volume
Loss (W)
• GaN solution has 3-4x
lower power loss
Loss Comparison (Fc=6kHz)
14.00
GaN Power Density
(module level) is 10x
higher than IGBT
module
12.00
10.00
• And GaN solution
does not require heat
sink
8.00
6.00
• GaN power Density
(including heatsink) is
>100X compared to
IGBT solution
4.00
2.00
IRAM 6A
Amps
0.00
0.5
1
1.5
GaN
2
23
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Rectifier. All Rights Reserved.
23
600 V rated device R-Q comparison table (RT)
Device type
R*Qoss (Ω-nC)
R*Qg(Ω-nC)
R*Qrr(Ω-nC)
Si SJ FET
4x
9x
224x
GaN cascode switch
1x
1x
1x
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24
600 V GaN vs Si SJ Switch in PFC Boost
Vin = 150 V, Vout= 400 V, Iav = 1 A, Freq= 100kHz, 25 C
10 ns / div, 100 V/ div
Turn on Switching Transient
160 mohm GaN
199 mohm Si
About 100 V/ns
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25
GaN vs Superjunction in Resonant DC:DC
®
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26
Synchronous Boost Efficiency 100 kHz
100kHz Boost
98.5%
Efficiency (%)
98.3%
98.0%
97.8%
97.5%
150
200
250
300
350
400
Vin = 150V
Vout = 400V
L = 500uH
Fsw = 100kHz
Forced air cooling
Pout (W)
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27
Synchronous Boost Efficiency 200 kHz
Vin = 150V
Vout = 350V
F = 200 kHz
L = 200uH
Fsw = 200kHz
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28
Efficiency of 5MHz GaN power supply
Efficiency of 5MHz GaN converter
100%
90%
80%
Efficiency
70%
95% Efficiency at 5 MHz
60%
50%
40%
30%
Vin=400V
Vo =200V
Po=100W
20%
10%
0%
0
20
40
60
80
100
120
140
Po (W)
with fan
29
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Rectifier. All Rights Reserved.
29
Potential GaNpowIR® Technology Roadmap
GaNpowIR® IC
600V
50-200
mOhm
600V
25-2000
mOhm
GaNpowIR®
System on
Chip
FETs and
Driver
Modules
Cascode
Discretes
2013
2014
2016
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2018
30
30
Summary
•
The development of the first Generation of 600 V GaN-on-Si based
power devices using International Rectifier’s GaNpowIR® technology
platform has been completed !
•
All required metrics for large scale commercial adoption have been
achieved !
•
There remains significant further improvement to reach the inherent
capability of this this technology.
•
An aggressive roadmap is in place at International Rectifier to drive
toward this maturity of GaN-on-Si based power devices.
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31
Dedication
Eric Lidow
Dec 1912 – Jan 2013
Founder of International Rectifier
And my Inspiration
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