Energy Distribution in Hostile
Environment:
Power Converters and Devices
Mauro Citterio
on behalf of the INFN-APOLLO project
Mauro Citterio
ICATPP Como – 10/4/2011
1
INDEX
• The ATLAS LAr Calorimeter System …. a test case
• The Proposed Power Distribution for an Upgraded LAr
System
• Characteristics of Power MOSFETs under irradiation
•
- exposed to ionizing radiation (gamma 60Co)
•
- exposed to heavy ions (75Br at 155 MeV)
•
- exposed to protons (216 MeV)
• Conclusions
Mauro Citterio
ICATPP Como – 10/4/2011
2
The ATLAS experiment
LAr barrel calorimeter
The power distribution
and conversion scheme
in the detector area
Mauro Citterio
ICATPP Como – 10/4/2011
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ATLAS Experiment: Lar Barrel Calorimeter
Details of the Front End Electronics and Main Power Converter
The required qualification doses for this application are:
4.5 x 104 rad and 2 x 1012 particles/cm2 (> 20 MeV)
 Ten times higher for Hi-LHC scenario (70 safety factor)!!!
Mauro Citterio
ICATPP Como – 10/4/2011
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ATLAS Experiment: Present Status
LAr Calorimeter Front-End Board (FEB) Power Distribution
19 LDO regulators/FEB
Mauro Citterio
ICATPP Como – 10/4/2011
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Proposed Power Supply Distribution Scheme for a LAr Upgrade
MORE INFO  TAKE A LOOK
AT THE DEDICATED POSTER !!!
CRATE
Card #3
Card #2POL
LDO
Converter
Card #1
POL
LDO
Converter LDO
280 Vdc
niPOL
ConverterLDO
Main
DC/DC
Converter
POL
Converter
POL
POL
Converter
LDO
Converter
POL
niPOL
Converter
LDO
Converter
Regulated DC bus
niPOL
Converter
POL
POL
POL
POL Converter with high step-down ratio
Characteristics:
•
•
•
Main isolated converter with N+1 redundancy
High DC bus voltage (12V or other)
Distributed Non-Isolated Point of Load Converters (niPOL) with high step-down ratio
Mauro Citterio
ICATPP Como – 10/4/2011
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Critical Elements for a LAr Upgrades
The Main Converter
The Point of Load
C+
4
C+
V
3
in
C+
2
C+
1
L T
iL 1
S
S
L
4
1
2
1
Q
T
C
3
3
o
+
V
- ou
t
+ S
C UC 4
-1
1
Uin
Q T
iT
2
Q
T
2
2
Q
1
C
L
R
Uo
-
o
2
S
4
3
Vout = 12V
D<50% Uo = UinD/2
POL Specifications:
Switched In Line Converter SILC
-
Required Mosfet Voltage
Breakdown: ~ 200 Volt or higher
-
Mosfets, diodes and controller must
be qualified against radiation
Mauro Citterio
+
Input voltage:
Output voltage:
Output current:
Operating frequency:
Ug = 12 V
Uo = 2.5 V
Io = 3A
fs = 1 MHz
350 nH air core inductors
ICATPP Como – 10/4/2011
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Power Mosfets exposed to gamma rays
Devices under test:
30V STP80NF03L-04
30V LR7843
200V IRF630
For each type of device 20 samples
were tested, 5 for each dose value
(tested at the ENEA Calliope Test
Facility)
Measurements :
Used doses:
Breakdown Voltage @ VGS=-10V
I 1600 Gray
Threshold Voltage @ VDS=5V
II 3200 Gray
ON Characteristic @ VGS=10V
III 5890 Gray
Gate Leakage @ VDS=10V
IV 9600 Gray
Mauro Citterio
ICATPP Como – 10/4/2011
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30 V Mosfet: STP80NF03L-04
Mauro Citterio
ICATPP Como – 10/4/2011
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30 V Mosfet: LR7843
Mauro Citterio
ICATPP Como – 10/4/2011
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200 V Mosfet: IRF630
Mauro Citterio
ICATPP Como – 10/4/2011
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Mosfet Exposed to Heavy Ions.
The SEE framework
Destructive Single Event Effects in Power MOSFETS
(tested at INFN Catania)
Source
Gate
Source
Body
Gate
Body
N+N+
P
P
_
N+N+
+
_
_
+
P
_
N
N
P
N
+
N
+
Drain
Drain
Single Event Burnout
Single Event Gate Rupture
Mauro Citterio
ICATPP Como – 10/4/2011
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The SEE experimental set-up
Gate Leakage Current [ A ]
The IGSS evolution during irradiation
0
-0.5
-1.0
-1.5
-2.0
0
500
1000
Time [s]
Source
1500
2000
Vgs
Gate
Vds
Parameter Analyzer
1 MW
1 MW
Body
Cd
N+N+
P
_
P
+
Impacting Ion DUT
The current pulses
Cg
15
Current [mA]
50 W
50 W
1
5
_
N
0
20
N
+
40
60
80
Time [ns]
100
120
Fast Sampling Oscilloscope
Drain
Mauro Citterio
ICATPP Como – 10/4/2011
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The SEE analysis
TIME DOMAIN WAVEFORMS
SCATTER PLOT
0
1.5
Current [mA]
1
0.5
0
1.5
1
0.5
0
20
x 10
40
60
Time [ns]
80
100
120
11
5
16
Charge [pC]
1.5
0.5
14
4
12
3.5
3
10
2.5
8
50
1
10
4.5
2.5
2
x 10
100
Vds [V]
150
2
1.5
Vds
1
0.5
0
0
10
30
40
10
Charge [pC]
MEAN CHARGE vs BIAS VOLTAGE
Mauro Citterio
20
30
40
10
Charge [pC]
20
30
40
Γ-LIKE DISTRIBUTION FUNCTION
ICATPP Como – 10/4/2011
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The SEE experimental results
200 V Mosfet: IRF630
Devise TID
D21
D22
D06
D10
D14
D16
D17
Mauro Citterio
0Gy
0Gy
1600Gy
3200Gy
5600Gy
5600Gy
9600Gy
Bias Conditions during
Irradiation
Vds=20V-110V vgs=-2V
Vds=20V-120V vgs=-6V
Vds=20V-70V vgs=-2V
Vds=20V-50V vgs=-6V
Vds=20V-55V vgs=-6V
Vds=20V-50V vgs=-6V
Vds=20V-45V vgs=-6V
Drain Damage
Gate Damage
Vds=100V-110V
Vds=110V-120V
Vds=60V-70V
Vds=40V-50V
Vds=50V-55V
Vds=45V-50V
Vds=40V-45V
Vds=100V-110V
Vds=100V-110V
Vds=60V-70V
Vds=40V-50V
Vds=40V-50V
Vds=40V-45V
Vds=40V-45V
ICATPP Como – 10/4/2011
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The SEE experimental results
D21 0Gy Vds=110V Vgs=-2V
0.4
0.35
Current [mA]
0.3
0.25
0.2
0.15
0.1
0.05
0
0
20
40
60
80
100
120
Time [ns]
140
160
180
200
D21 0Gy Vds=110V Vgs=-2V
35
30
25
Current [mA]
2.8
2.6
Charge [pC]
2.4
2.2
20
15
10
2.0
5
1.8
0
1.6
0
20
40
1.4
20
30
Mauro Citterio
40
50
60
Vds [V]
70
80
90
60
80
100
120
Time [ns]
140
160
180
200
100
ICATPP Como – 10/4/2011
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The SEE experimental results
Scatter-plot Vds=50V
120
100
Current [A]
80
D21
0Gy
D10 3200Gy
D14 5600Gy
D17 9600Gy
60
40
20
0
-20
0
Mauro Citterio
20
40
ICATPP Como – 10/4/2011
60
80
100
120
Time [ns]
140
160
180
200
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Mosfet Exposed to Protons
SEB characterization
Characterization requires that an SEB circumvention method be utilized
SEB characterization produces a cross-sectional area curve as a function of LET for a fixed VDS
and VGS.


Generally SEB is not sensitive to changes in the gate bias, VGS.
However, the VGS bias shall be sufficient to bias the DUT in an “off” state (a few volts below
VTH), allowing for total dose effects that may reduce the VTH.
The only difference in the test
set-up was that the current probe
was on the Mosfet Source
Mauro Citterio
ICATPP Como – 10/4/2011
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Mosfet Exposed to Protons
The results are still preliminary. Only the 200V Mosfets (IRF 630, samples from two
different manufacturers) were exposed
Proton energy: 216 MeV
Ionizing Dose: < 30 Krads
(facility at Massachusetts General Hospital, Boston)
An “absolute” cross section will require the knowldege of the area of the Mosfet die which is
unknown.
IRF630 - International Rectifier
IRF630 - ST
-7
10
-7
10
-8
10
-8
Cross Section [cm-2]
Cross Section [cm-2]
10
-9
10
-10
10
-9
10
-10
10
-11
10
-11
10
-12
10
-12
10
175
180
185
190
190
195
182
186
188
190
192
194
196
VDS [Volt]
VDS [Volt]
Mauro Citterio
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ICATPP Como – 10/4/2011
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Mosfet Exposed to Protons
Work still in progress ……………..
 The number of SEB events recorded at each VDS was small
 less then 30 events for the ST
 less than 150 events for the IR devices
 Large statistical errors affect the measurements
 The cross section at VDS = 150 V (“de-rated” operating voltage) can not be
properly estimated
 Dependence from manufacturer
 “Knee” not well defined
• To effectively qualify the devices for 10 years of operation at Hi-LHC, the
cross section has to be of the order of 10-17/ cm2, which puts the failure rate at
<1 for 10 years of operation
• Proton irradiation campaigns with increased fluences and more samples are
planned.
Mauro Citterio
ICATPP Como – 10/4/2011
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Conclusions
 Distributed Power Architecture has been proposed
 Main converter (SILC topology)
 Point of load converter (IBDV topology)
 Critical selcction of components to proper withstand radiation
 Controller, Driver and Isolator
 FPGA for overall monitoring
 MOSFETS
 MOSFETS, both for main converter and POL have been selected and tested
 Gamma ray
 Heavy ions
 Protons
 Some results are encouraging, however more systematic validation is on-going
 Novel devices based on SiC and GaN, are also under investigation
Mauro Citterio
ICATPP Como – 10/4/2011
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