3. Computer Simulation. - Device simulation. - Circuit simulation. 4. SET testing. â. Broad Beam of Protons and Heavy ions. â. Pulsed laser light. 5. Case Studies.
Single Event Transients in Linear Integrated Circuits Stephen Buchner QSS Group Inc./NASA GSFC
Dale McMorrow Naval Research Laboratory
L. Cohn A. Clark
K. LaBel S.Buchner, C.Poivey, J.Howard, R.Ladbury
A.Sternberg, Y.Boulghassoul, T.Holman L.Massengill J.Rowe
D.McMorrow, W.Lotshaw
R.Pease
M.Savage, T.Turflinger, J.Titus D. Platteter
1
Course Outline 1. Introduction 2. Fundamental Mechanisms – – –
Charge generation Charge collection Device Response
3. Computer Simulation -
Device simulation Circuit simulation
4. SET testing – –
Broad Beam of Protons and Heavy ions Pulsed laser light
5. Case Studies 6. Mitigation 7. Conclusions
1. Introduction
2
Introduction • Definition of a SET An SET is a temporary disruption to the output of a device (transistor) or circuit caused by an ionizing particle passing through the device.
• SETs occur in Digital and Analog circuits. DSETs and ASETs
• SETs occur in bipolar, CMOS, BiCMOS and compound semiconductor (III-V) technologies.
Introduction • This Short Course deals with ASETs in Linear Integrated Circuits. – – – – – – – –
Op-amps Comparators Voltage references Pulse width modulators Voltage controlled oscillators DC/DC Converters Phase Lock Loops Digital-to-Analog Converters
3
Introduction • SETs appear as voltage “glitches” at the outputs of: R1 – – – –
Op-amps, Comparators, Voltage refs, DACs
R2
Vin
Vout
+
10
Amplitude (V)
9 8 7 6 5 4 0
2
4
6
8
10
12
14
Time (µ µs)
Introduction • SETs, or voltage glitches, are just another form of noise. Effect on system determined by amplitude and width (∆Vmin,∆tmin). ∆Vout R1
R2
∆t
Vin
Follow-on Circuit
+ CLK
4
Introduction 6.5
Q2 Q4 Q5
6.0 5.5
ASETs in Op-amps (LM124)
5.0 6.0
• ASETs assume a wide variety of shapes. In the LM124 there are at least five different types. • Each ASET type also has a variety of amplitudes.
4.0
2.0
Q9 Q 19
Vout (V)
0.0 7.0
Q 18
6.5 6.0 5.5 5.0 10
Q 20
9
• Not all ASETs pose a threat. • Transient widths often related to circuit bandwidth.
8 7 6 5 8 7 6 5 4 3 2 1
Q 16
Buchner et al IEEE TNS 2004 0
5
10
15
T im e (m icrose co n ds)
Introduction ASETs in Voltage Compators (LM119) 5
• ASETs are all either positivegoing or negative-going depending on whether output is high or low.
4
Q6
3 2 1 0 5 4
Q3
3
• The shape stays the same as ∆V and ∆t change.
2 1 0 5 4
Q2
3 2 1 0 0
0.2
0.4
0.6
0.8
1
Buchner et al HEART 2001
µs) Time (µ
5
Introduction SETs appear as disruptions to the outputs of: Voltage Controlled Oscillators
Pulse Width Modulators
Chen et al IEEE TNS 2003
Howard et al Data Workshop 2003
Introduction Satellites Exhibiting ASETs (Partial List) • • • • • •
Topex/Poseidon (OP-15)………….. 1993 SOHO (LM/PM139)………………... 1996 Cassini (LM139)……………………. 1998-2002 TDRS (LM139)………………………1997 MPTB (LM124 and LM139) ………. 1997 MAP (LM139)………………………..2001
6
Introduction ASETs on MAP • Launched June 30, 2001. • A reset of the spacecraft processor occurred on November 5, 2001. • Caused the spacecraft to go into “safehold.” • Solar event on Nov. 5, 2001.
Poivey RADECS 2002
Introduction Processor Reset Circuit contains Comparators +5V (Min=4.3V)
+5V R=1k
R=3.6k 2.9V
EEP_RESET (∆ ∆=2.5V) LM139
R=5.1k
Vref=2.5V HW_RESET (∆ ∆=2.5V)
+5V R=100k
2.9V LM139 Vref=2.5V
5V
R=1.5k C=10 µF
R=10k
LM139 Vref=2.5V Poivey RADECS 2002
7
Introduction ASETs for the LM139 Comparator
Output Voltage (V)
Vt = 2.5 V
4
2
0
-2
-4 1.2 10
2
LM 139, V =+/-5, δ V =800m V, LET=18.7 M eV-cm /m g cc
-5
1.4 10
-5
1.6 10
-5
1.8 10
-5
i
2 10
-5
2.2 10
-5
2.4 10
-5
2.6 10
-5
2.8 10
-5
Tim e (s) Poivey RADECS 2002
Introduction Summary: • ASETs occur in a wide variety of linear devices. • The nature of the ASET depends on the device. • ASETs have caused problems in a number of spacecraft.
8
2. Fundamental Mechanisms
Fundamental Mechanisms Interaction of ions with matter Ionization 1. Coulomb interaction between nucleus and bound electrons. 2. It requires, on average, 3.6 eV to create 1 electron-hole pair in Si. 3. Energetic electrons (delta rays) create additional e-h pairs as they move through lattice. 4. Result is a track of charge with a diameter < 1 µm.
SILICON
9
Fundamental Mechanisms Interaction of ions with matter Ionization 1. Coulomb interaction between nucleus and bound electrons. 2. It requires, on average, 3.6 eV to create 1 electron-hole pair in Si. 3. Energetic electrons (delta rays) create additional e-h pairs as they move through lattice. 4. Result is a track of charge with a diameter < 1 µm. 5. Charge Track expands rapidly via diffusion.
SILICON
Fundamental Mechanisms Interaction of ions with matter Ionization 1. In the presence of a p-n junction charge is collected via drift in the junction electric field.
N-type
P-type
SILICON
10
Fundamental Mechanisms Unbiased p-n Junction. n-Type
E
p-Type
Depletion Layer
EC
EF
EV
Fundamental Mechanisms Forward-biased p-n junction. n-Type
E
-
p-Type
+ Depletion Layer
EC EV
11
Fundamental Mechanisms Reverse-biased p-n junction. n-Type
+
E
p-Type
-
Depletion Layer
EC EV
Fundamental Mechanisms Charge Collection via Drift Large electric field collects charge via drift, an efficient process. E +
-
n-Type
+
+
p-Type
-
-
n-Type EC
+
EV +
p-Type
12
Fundamental Mechanisms Charge Collection by Diffusion Electrons and holes generated far from the junction will diffuse slowly to the junction. +
100 µm
+
EC EV
-
E
-
n-Type p-Type
+
Fundamental Mechanisms ASETs Shapes
Electric Potential (V)
Fast (drift) and slow (diffusion) components. (Shape depends on applied bias).
Drift Component
Diffusion Component
Time (ps)
13
Fundamental Mechanisms Bipolar Transistor Two back-to-back p-n junctions. Emitter
Base
n
p
Collector n
EC
EF
EV
Emitter
Base
Collector
Fundamental Mechanisms Forward-active mode Holes injected into C/B junction drift into base and turn the transistor more on. Emitter
Base
n
p
Collector n
V2
V1 -
-
+ +
Emitter
Base
Collector
14
Fundamental Mechanisms Charge Collection in Vertical n-p-n Transistor. E
C n+
B p
n+
p+
p+
n-epi n+
p-substrate
Fundamental Mechanisms Differential pair: Used as inputs for op-amps and voltage comparators. V+
V2 V1
+
I2
I1 V1
If: V1 = V2 then I1 = I2 and Vout(1)=Vout(2)
R
R Vout(1)
Tr1
Tr2
Vout(2) V2
IE
15
Fundamental Mechanisms Differential pair: If: V1 > V2 then I1 > I2 and Vout(2) is high Vout(1) is low
V+
R
R Vout(1)
I2
I1 V1
Tr1
Vout(2) V2
Tr2
IE
Fundamental Mechanisms Differential pair: Assume V1 > V2 V+
R
R I2
I1 V1
As V1-V2 increases, more charge is needed to produce an ASET.
Tr1
Tr2
V2
IE
16
Fundamental Mechanisms LM111
• Input transistors are most sensitive to SETs. VIN
VOUT
• SETs propagate from input transistor to output.
Fundamental Mechanisms Summary • Particles passing through matter produce electronhole pairs. • Electric fields associated with p-n junctions separate the electrons and holes. • This causes a change in the potential at the node. • In a BJT the charge can make a transistor more conducting and that alters the internal potentials. • The potential disturbance travels through the circuit to the output where it appears as an ASET.
17
3. Computer Simulation
Computer Simulation • Device simulator – E.g. SILVACO, PISCES, etc (Only two published reports)
• Circuit simulator – E.g. SPICE.
18
Computer Simulation 1. Device Simulation Simulation of the device behavior by the solution of the following equations describing charge flow in the device. • Maxwell’s Equations • Poisson’s Equations • Continuity Equations • Carrier Transport Equations Non-linear differential equations cannot be solved analytically. A computer is used to solve the equations numerically in space and time.
Computer Simulation 1. Device Simulation B
E p
n+ n-epi
p+
400 µm
p+
p-substrate
Substrate p-n-p
VBE = -0.42 V – weakly on. Johnston IEEE TNS 2000
19
Computer Simulation 1. Device Simulation
B
E p
n+ n-epi
p+
400 µm
p+
Johnston IEEE TNS 2000
p-substrate
Substrate p-n-p
Emitter Base
Collector
Computer Simulation 1. Device Simulation Issues: • Device simulation does not include the circuit response. A circuit simulator (SPICE) would have to be included to model the propagation of the ASET through the circuit (Mixed Mode). • It is also impractical for doing an entire circuit that might have 50 transistors or more.
20
Computer Simulation 2. Circuit Simulation (SPICE): Require: • Circuit interconnects • Identities of devices (transistors, resistors, etc) • Gummel-Poon values for transistors
Validate SPICE Model for Normal Operation: • Calculate the circuit response (output) to various input signals to validate the model
Validate SPICE Model for ASETs: • Comparison of calculated ASETs with experimental ASETs using a feedback process until the transient shapes match.
Computer Simulation Identify Circuit Elements and Interconnects Q19
Q16
Q15
LM124 Q21
Q20 R1
Q5
Q17 Q2
Q4
Q3
C
Q9
21
Computer Simulation Identify Circuit Elements and Interconnects V+ Q16
Q15 Q14
Q19 Vin(+) C1
Q12
Q18 Q20
LM124
Vin(-)
Q13
R2 Q7
R1
Vout
Q6 Q11
Q17 Q21
Q9 Q5
Q2 Q3
Q8
Q10
Q4
V-
Computer Simulation Need SPICE Transistor Parameters LM124 • Obtain SPICE transistor parameters from data sheets or from manufacturer. • Otherwise, must isolate transistor with focused ion beam (FIB) milling and measure I-V curves to obtain Gummel-Poon parameters.
22
Computer Simulation SPICE Validation – Small and Large Input Signals
Input: 100 mV 10 µs +
-
Output
LM124 Sternberg IEEE TNS 2002
Computer Simulation Spice Model (LM124) Validation – Shape of I(t) does not affect ASET V+
I(t)
Q16
Q15 Q14
Q19 Vin(+)
C/B
C1
Q12
Q18 Q20 Vin(-)
R1
Vout
Q6 Q11
Q17
I(t)
Q21
E/B
Q13
R2 Q7
Q9 Q5
Q2 Q3
Q8
Q10
Q4
I(t) E/C
V-
23
Computer Simulation SPICE Simulation – ASET Validation via Iteration Compare SETs generated by pulsed laser or ion microprobe with those calculated using SPICE. Agreement? Poor
Good
Modify circuit and device parameters.
Stop.
Computer Simulation SPICE Simulation – ASET Validation
24
Computer Simulation ASET Dependence on Compensating Capacitance
Sternberg IEEE TNS 2002
Computer Simulation Constant Gain but Different Values of R1/R2 R1 Vin
R2
+
Gain =
R1 = 10 R2
Vin = -60 mV Vout = 600 mV Sternberg IEEE TNS 2002
25
Computer Simulation Summary • Device simulation provides detailed information about mechanisms responsible for ASETs. • Circuit simulation is suitable for studying ASETs with response times longer than the charge collection time. • The validity of the circuit model is established by comparing actual and calculated responses to input signals, but that is not sufficient……….. • The model must also be validated by comparing calculated ASET shapes with those obtained experimentally. • Circuit simulation can be used to study effects of circuit parameters on ASET shapes.
4. ASET Testing
26
ASET Testing Testing Approaches: 1. Broad beam of heavy ions or protons 2. Pulsed Laser 3. Ion micro-probe 4. Radioactive source (252Cf)
ASET Testing
1. Broad Beam of Heavy Ions
27
ASET Testing (Broad Beam) Standard Approach for SEU Testing
2. Irradiate Device with Ions having selected LET
1. Program Device
3. Read Number of Upsets
# of Upsets
σ = Fluence
4. Calculate Cross Section
σ(LET) 5. Irradiate Device with Ions having different LET
ASET Testing (Broad Beam) Standard Approach for SEU Testing
Cross-Section (cm2)
The goal is to predict the error rate in space
• Fit the data with a Weibull curve. • Use the curve as input in a program such as CREME96 to calculate SEU rate.
LET (MeV.cm2/mg)
28
ASET Testing (Broad Beam) Modifications for ASET Testing
DUT
Computer
Oscilloscope
Probe
1. Carefully establish device configuration (voltages, trigger levels etc). 2. Establish a method for counting the ASETs 3. Use active probe or test in actual application 4. Capture and store all transients for later analysis of ∆V vs ∆t.
ASET Testing (Broad Beam) Store all Transients 6 9
5 4
8 7 6
3 2
5 4 3
1 0
2 1
-5 0
1.6 1.4 1.2
8 1.4 7 1.2
1
6
0.8
5
1 0.6 0.4 0.2 0 -5 -0.2
0.8 4 0.6
Width
3 0.4 2
0 1
0.2 0
5
0
-5 0
10 5
10
0 -5 -0.2
15
5 0
-5
Amplitude 15 20 10 5
0
5
25 20
30 25
15 10
20
10
15
30 25
15
30 20
20
25 25
30
Adell et al. IEEE TNS 2000.
29
ASET Testing (Broad Beam) Analysis of Test Data – Pulse Height vs Pulse Width LM124 - LET = 2.8 MeV·cm2/mg 15
Output Signal, V
Pulse Amplitude (V)
10
5
5 0 -5 -10
-5
-15 0
10
20
30
Time, µs
-15
0
5
10
15
Pulse Width (µs)
ASET Testing (Broad Beam) Analysis of Test Data – Pulse Height vs Pulse Width
SET Amplitude, V
10 5
LM124
0
LET = 53.9 MeV·cm2/mg; Voltage Follower.
-5 -10 -15
0
5
10
15
SET Pulse Width, µs
30
ASET Testing (Broad Beam) Effect of Application on σ(LET) 2
Cross-Section (cm )
1.E-02
σsat
1.E-03
1.E-04
Rate ~ 1.E-05
σsat (LETth)2
1.E-06 0
20
40
60
80 2
LET (MeV.cm /mg)
100
120 Poivey GSFC Report
ASET Testing (Broad Beam) Factors that affect ASET Cross-Section 1. 2. 3. 4. 5.
Oscilloscope trigger level Input voltage Supply voltage Gain Output loading
31
ASET Testing (Broad Beam) Factors that affect ASET Cross-Section
Oscilloscope trigger level ∆VT = 50 mV o ∆VT = 300 mV ∆ ∆VT = 700 mV
LM111
Koga et al. IEEE TNS 1993
ASET Testing (Broad Beam) Factors affecting ASET Cross-Section: (V2-V1)
V2 LM139 V1
Koga et al. IEEE TNS 1997
32
ASET Testing (Broad Beam)
Cross Section (cm2/device)
Factors affecting ASET Cross-Section: Vs V+
LM111
V-
Vs = +/-15V, ∆Vin=50 mV
1.0E-03 Vs = +/-5V, ∆Vin=50 mV
1.0E-05
1.0E-07 0
10
20
30
40
50
60
70
LET (MeV.cm2/mg) Koga et al. IEEE TNS 1997
ASET Testing (Broad Beam) Factors affecting ASET Cross-Section: Output Loading 6
5.0 V V+
Amplitude (V)
5
R
4
R=0.17 kΩ Ω
3 2 1 0 -1
LM119
6
0
2
4
6
8
10
µs) Time (µ
V-
Amplitude (V)
5 4 3
R=1.7 kΩ Ω
2 1 0 0
2
4
6
8
10
µs) Time (µ
33
ASET Testing (Broad Beam) Effects of Ion Range
TAMU: • 15 MeV/amu has range ~ 150 µms • 25 MeV/amu has range ~ 400 µms • 40 MeV/amu has range ~ 1,000 µms BNL: • 2 - 8 MeV/amu has range ~ 50 µms
Poivey GSFC Report
ASET Testing
2. Pulsed Laser
34
ASET Testing (Heavy Ions) Pulsed Laser ASET Testing Technique •
Use light instead of particles to generate free carriers (electrons and holes). Particles
Absorption
Coulomb interaction between nucleus of incident particle and bound electrons of Si
Absorption of photons by bound electrons of Si
ASET Testing (Pulsed Laser) Comparison of Ion and Laser-light Induced Charge Tracks λ=800 nm
0
30 MeV Ar
2 µ
Depth in Material, µm
2
λ=590 nm
0
1/e Contour
4
6
w(z)
1/e Contour
4
6
w(z)
8
8
10
10 -4
-2
0 Distance, µm
2
4
-4
-2
0
2
4
Distance, µm
35
ASET Testing (Heavy Ions) Pulsed Laser ASET Testing Technique • • •
Can focus light to a diameter of ~ 1 µm to obtain spatial information – origins of ASETs. Light source must be a pulsed laser with pulse width shorter than the response time of the circuit ~ 1 ps. Particularly well suited for studying ASETs in linear devices because sensitive areas are large compared to size of beam and relatively little metal on surfaces to block beam.
ASET Testing (Pulsed Laser) Two Approaches: 10
5
10
4
10
3
10
2
10
1
10
0
One Photon:
Absorption Coefficient, cm
-1
600 nm
10
600 nm, 800nm, 1.06 µm
800 nm
Above band gap Single-photon absorption
1.06 µm
Two Photon: λ > 1.15 µm 1.26 µm
-1
400
600
800 1000 Wavelength, nm
1200
Sub-bandgap Two-photon absorption
1400
36
ASET Testing (Pulsed Laser) Two Approaches:
1-Photon
2-Photon -
Ec
Ec
600 nm
1260 nm
Eg=1.1eV
Ev
Ev
- - +-
-
-
+-
ASET Testing (Pulsed Laser) One-Photon Absorption SEE Experiment Carrier generation equation:
dN ( r , z ) αI ( r , z ) = dt ω 0
2
1 /e C o n to u r
w (z )
4
•
Carrier generation is proportional to the intensity of the incident laser pulse
•
Because the loss is linear in the incident pulse intensity, the pulse experiences exponential attenuation from the surface of the material:
6
I ( r , z ) = I o e −αz
8
10 -4
-2
0
2
4
P o s it io n , µ m
37
ASET Testing (Pulsed Laser) Two-Photon Absorption SEE Experiment Carrier generation equation:
•
0
dN ( r , z ) αI ( r , z ) β 2 I 2 ( r , z ) = + ω 2 ω dt
w (z )
20
10
2
1 /e C o n to u r 30
Depth in Material, µm
N α I
-4
-2
0 P o s itio n , µ m
2
Carriers are generated by nonlinear absorption at high pulse irradiances by the simultaneous absorption of two photons • Carriers are highly concentrated in the high irradiance region near the focus of the beam • Because of the lack of exponential attenuation, carriers can be injected at any depth in the semiconductor material
4
ASET Testing (Pulsed Laser) Carrier Density Distribution: 1-Photon vs. 2-Photon Absorption 0
0
800 nm
1/e Contour
4
6
w(z)
2
µ
w(z)
1/e Contour
30
Depth in Material, µm
2
Depth in Material, µm 20 10
NαI
8
10 -4
-2
0 Distance, µm
2
4
-4
-2
0 2 Position, µm
4
38
ASET Testing (Pulsed Laser) Pulsed Laser SEE Experimental Apparatus ps or fs laser source laser pulse
PD1
λ/2 Polarizer
DUT
xyz
ccd PD2 camera
ASET Testing (Pulsed Laser)
Validate Technique
39
ASET Testing (Pulsed Laser) Devices Sensitive to SETs (LM124) V+ Q16
Q15 Q14
Q19 Vin(+)
Q13
R2 Q7
C1
Q12
Q18 Q20
R1
Vout
Q6
Vin(-)
Q11
Q17 Q21
Q9 Q5
Q2 Q3
Q8
Q10
Q4
V-
ASET Testing (Pulsed Laser) SETs: Comparison of Pulsed Laser Light and Low LET Heavy Ions 1.5
Q18
1.2 1.4
Vout (V)
1.1
LM124 Inverting Configuration:
1.3
1.0
1.2
Q2
Vdd = +/-6 V Vin = 60 mV
1.2
1.2
1.1
1.1
1.0
1.0 40 MeV Cl 590 nm Laser
Q6 0
5 10 Time ( µ s)
0.9
15
40 MeV Cl 590 nm Laser
Q20 0
5
10
15
20
Time (µs) Buchner et al. IEEE TNS 2003
40
ASET Testing (Pulsed Laser) SETs: Comparison of Pulsed Laser Light and High LET Heavy Ions 6.5
5.5 Vout (V)
7.0
Q2 Q4 Q5
6.0
6.0
LM124 Voltage Follower:
5.5
5.0
5.0
6.0
10 9 8 7 6 5
4.0 2.0 0.0
Q18
6.5
Q9 Q19 0
5 Time, µs
10
15
Q20
0
5
10
Vdd = +/-15 V Vin = 5 V
15
Time, ms Pease et al. IEEE TNS 2002
ASET Testing (Pulsed Laser)
How do we handle these transients?
41
ASET Testing (Pulsed Laser) Generate Plots of Amplitude vs Width Q19
Q20, C1
Q16
Q15
Q21 R1
Q5
Q17 Q2
Q4
Q3
Q9
C
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q20 (C1) Q20 V∆t Plot 10
5
Output Signal, V
SET Amplitude, V
10
0 -5 -10
0 -5 -10
-15 -20
5
-15
0
5
10 Pulse Width, µs
15
20
0
10
20
30
Time, µs
42
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q20 (C1) Q20 V∆t Plot
10
5
Output Signal, V
SET Amplitude, V
10
0 -5 -10
0 -5 -10
-15 -20
5
-15 0
5
10
15
0
20
10
20
30
Time, µs
Pulse Width, µs
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q20 (C1) Q20 V∆t Plot
10
5
Output Signal, V
SET Amplitude, V
10
0 -5 -10
0 -5 -10
-15 -20
5
-15 0
5
10 Pulse Width, µs
15
20
0
10
20
30
Time, µs
43
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q20 (C1) Q20 V∆t Plot
10
5
Output Signal, V
SET Amplitude, V
10
0 -5 -10
0 -5 -10
-15 -20
5
-15 0
5
10
15
0
20
10
20
30
Time, µs
Pulse Width, µs
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q20 (C1) Q20 V∆t Plot
10
5
Output Signal, V
SET Amplitude, V
10
0 -5 -10
0 -5 -10
-15 -20
5
-15 0
5
10 Pulse Width, µs
15
20
0
10
20
30
Time, µs
44
ASET Testing (Pulsed Laser) Generate Plots of Amplitude vs Width Q19
Q20, C2
Q16
Q15
Q21 R1
Q5
Q17 Q2
Q4
Q3
Q9
C
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q20 (C2) Q20 V∆t Plot
SET Amplitude, V
10 5 0 -5 -10 -15 -20
0
5
10
15
20
Pulse Width, µs
45
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q20 (C2) Q20 V∆t Plot
10
5
Output Signal, V
SET Amplitude, V
10
0 -5 -10
0 -5 -10
-15 -20
5
-15 0
5
10
15
0
20
10
20
30
Time, µs
Pulse Width, µs
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q20 Q20 V∆t Plot
10
5
Output Signal, V
SET Amplitude, V
10
0 -5 -10
0 -5 -10
-15 -20
5
-15 0
5
10 Pulse Width, µs
15
20
0
10
20
30
Time, µs
46
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q20 Q20 V∆t Plot
10
5
Output Signal, V
SET Amplitude, V
10
0 -5 -10
0 -5 -10
-15 -20
5
-15 0
5
10
15
0
20
10
20
30
Time, µs
Pulse Width, µs
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q20 Q20 V∆t Plot
10
5
Output Signal, V
SET Amplitude, V
10
0 -5 -10
0 -5 -10
-15 -20
5
-15 0
5
10 Pulse Width, µs
15
20
0
10
20
30
Time, µs
47
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q20 Q20 V∆t Plot
10
5
Output Signal, V
SET Amplitude, V
10
0 -5 -10
0 -5 -10
-15 -20
5
-15
0
5
10
15
0
20
10
20
30
Time, µs
Pulse Width, µs
ASET Testing (Pulsed Laser) Generate Plots of Amplitude vs Width Q19
Q16
Q15
R1
Q21 Q5 Q17 Q2
Q4
Q3
C
Q9
48
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: R1 Q20 V∆t Plot
10
Output Signal, V
SET Amplitude, V
10
5
0
-5
5
0
-10 0.0
0.5
1.0
1.5
2.0
2.5
3.0
0
Pulse Width, µs
5
10
15
Time, µs
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: R1 Q20 V∆t Plot
10
Output Signal, V
SET Amplitude, V
10
5
0
-5
5
0
-10 0.0
0.5
1.0
1.5
2.0
Pulse Width, µs
2.5
3.0
0
5
10
15
Time, µs
49
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: R1 Q20 V∆t Plot 10 Output Signal, V
SET Amplitude, V
10
5
0
-5
5
0
-10 0.0
0.5
1.0
1.5
2.0
2.5
0
3.0
5
10
15
Time, µs
Pulse Width, µs
ASET Testing (Pulsed Laser) Generate Plots of Amplitude vs Width Q15 Q19 Q16 Q21 Q5 Q17 Q2
Q4
Q3
C
Q9
50
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q19 Q20 V∆t Plot
0 Output Signal, V
SET Amplitude, V
0 -5 -10 -15 -20
-5 -10 -15 -20
0
5
10
15
20
25
30
0
10
Pulse Width, µs
20
30
Time, µs
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: Q16 10
10
5
5
Output Signal, V
SET Amplitude, V
Q20 V∆t Plot
0 -5 -10
0 -5 -10 -15
-15 -20
-20 0.0
5.0
10.0
15.0
Pulse Width, µs
20.0
25.0
-5
0
5
10
15
20
25
30
35
Time, µs
51
ASET Testing (Pulsed Laser) 590 nm Pulsed Laser ASET Data: All Nodes Q5
R1,Q6,Q16
10
Q18
SET Pulse Amplitude, V
Q4
5
Q2
0 -5
Q20
-10 -15
Q9,Q16,Q19 Q20
-20 0
5
10
15
20
25
30
SET Pulse Width, µs
ASET Testing (Pulsed Laser) Comparison of Heavy Ion and Laser Data
Q5
R1,Q6,Q16
10
10
Q18
SET Pulse Amplitude, V
Q4
SET Amplitude, V
5 0 -5 -10 -15
5
Q2
0 -5
Q20
-10 -15
Q9,Q16,Q19 Q20
-20 0
5
10
SET Pulse Width, µs
15
0
5
10
15
20
25
30
SET Pulse Width, µs
52
ASET Testing (Pulsed Laser)
Sub-bandgap 2-photon absorption induced SEE: • Deposit charge at different depths • Backside irradiation
ASET Testing (Pulsed Laser) Comparison of 1-Photon and 2-Photon SET
Output Signal, V
5 4 3 2 1
LM119 Q6 1260 nm 590 nm
0 -0.1
0.0
0.1
0.2
0.3
0.4
0.5
Time, µs
53
ASET Testing (Pulsed Laser) LM124 Q20: General Characteristics
P (C2)
P (E)
N+ (B)
P (C1)
Overlayers
P
C1
C2
N (base)
E
12 µm
N+ (buried layer)
B
P+ (iso)
P+ (iso) P (substrate)
McMorrow et al. IEEE TNS 2003
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
P+ (iso) P (substrate)
6
P
Output Signal, V
P (C2)
4 2 0
Z = -15 µm -2 0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
54
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
6
P
P+ (iso)
Output Signal, V
P (C2)
4 2 0
Z = -6 µm -2
P (substrate)
0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
P+ (iso) P (substrate)
6
P
Output Signal, V
P (C2)
4 2 0
Z = -2 µm -2 0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
55
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
6
P
P+ (iso)
Output Signal, V
P (C2)
4 2
Z = 0 µm
0 -2
P (substrate)
0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
P+ (iso) P (substrate)
6
P
Output Signal, V
P (C2)
4 2
Z = 4 µm
0 -2 0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
56
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
6
P
P+ (iso)
Output Signal, V
P (C2)
4 2
Z = 7 µm
0 -2
P (substrate)
0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
P+ (iso) P (substrate)
6
P
Output Signal, V
P (C2)
4 2
Z = 13 µm
0 -2 0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
57
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
6
P
P+ (iso)
Output Signal, V
P (C2)
4 2
Z = 20 µm
0 -2
P (substrate)
0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
P+ (iso) P (substrate)
6
P
Output Signal, V
P (C2)
4 2
Z = 25 µm
0 -2 0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
58
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
6
P
P+ (iso)
Output Signal, V
P (C2)
4 2
Z = 38 µm
0 -2
P (substrate)
0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
P+ (iso) P (substrate)
6
P
Output Signal, V
P (C2)
4 2
Z = 44 µm
0 -2 0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
59
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
6
P
P+ (iso)
Output Signal, V
P (C2)
4 2 0
Z = 47 µm -2
P (substrate)
0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
ASET Testing (Pulsed Laser) Z” Dependence: LM124 Q20 C1-epi Junction (Inverting Configuration; gain of 20) Overlayers P (C1)
N (base)
12 µm
N+ (buried layer) P+ (iso)
P+ (iso) P (substrate)
6
P
Output Signal, V
P (C2)
4 2 0
Z = 53 µm -2 0
10
20
30
Time, µs McMorrow et al. IEEE TNS 2003
60
ASET Testing (Pulsed Laser) Overlayers P (C1)
P (C2)
P
0
-1
N (base) -2
N+ (buried layer)
“C1” Transient
-3
P+ (iso)
0
P+ (iso)
10
20
30
P (substrate) 6
C1-Sub “Shunt”
5
0.0
4 3
-0.5
2 1 0
-1.0
“C2” Transient -1.5
0
10
20
-1
0
10
20
30
30
ASET Testing (Pulsed Laser)
Sub-bandgap two-photon absorption - backside irradiation
61
ASET Testing (Pulsed Laser) Backside “Through-Wafer” TPA Illumination
Circuit Layer(s)
Substrate transparent to single photon sub-bandgap excitation
Tightly focused twophoton excitation source
Surface elements opaque to optical excitation
Region of 2 Photon Carrier Generation McMorrow et al. IEEE TNS 2004
ASET Testing (Pulsed Laser) Photomicrograph of Q20 in LM124 Captured with NIR InGaAs Camera
Back Side
Front Side
62
ASET Testing (Pulsed Laser) Backside “Through-Wafer” TPA Illumination LM124 Operational Amplifier 1.5
Q18
Front Side Back Side
Output Signal, V
1.0 0.5 0.0 Q18 2.0 1.0 0.0 0
5
10
15
20
McMorrow IEEE TNS 2004
Time, µs
ASET Testing (Pulsed Laser)
X-Y Scanning……..
63
ASET Testing (Pulsed Laser) 2D Scan of LM6144 Op-Amp
Area 1
V. Pouget, IXL, France
ASET Testing (Pulsed Laser) 2D Scan of LM6144 Op-Amp
10 9
Amplitude (V)
8 7 6 5 4 3 2 1 0 0.00
10.00
20.00
30.00
40.00
50.00
µs) Time (µ
V. Pouget, IXL, France
64
ASET Testing (Pulsed Laser) 2D Scan of LM6144 Op-Amp
V. Pouget, IXL, France
ASET Testing Summary • ASET testing has unique aspects. – Sensitivity to configuration – Need to capture transients – Analysis to determine which transients are of concern
• The approaches discussed in this section are in large part a result of the DTRA program. • The best approach is to use a number of different experimental methods including: – Broad beam of heavy ions – Focused beam of heavy ions – Pulsed laser (1-photon and 2-photon)
• ASET sensitivity depends critically on configuration.
65
5. Case Studies
ASETs Originating in Resistors in LM119 Voltage Comparator
66
Case Studies – LM119 LM119 Circuit
Sternberg, IEEE TNS 2002
Case Studies – LM119 Resistor R11 shows ASET sensitivity Laser
Simulation
Laser
Sternberg, IEEE TNS 2002
67
Case Studies – LM119 Comparison of experimental and simulated results
Sternberg, IEEE TNS 2002
Spreading Resistance for Input Transistors in LM111 Voltage Comparator
68
Case Studies – LM111 Validating the SPICE Model for the LM111 I(t) C/B
I(t) E/B
I(t) E/C
Pease et al. IEEE TNS 2002
CASE STUDIES LM111 Validating the SPICE Model for the LM111
Photomicrograph Of LM111 input
Location of ASETs in LM111 Induced by ion microprobe Pease et al. IEEE TNS 2002
69
Case Studies – LM111 Validating the SPICE Model for the LM111
Collector
Base
Emitter
Sternberg, IEEE TNS 2002
Case Studies – LM111 Validating the SPICE Model for the LM111
Pease, IEEE TNS 2002
70
ASETs originating in Resistor in LM124
Case Studies – LM124 Validating the SPICE Model for the LM124
Heavy Ion
71
Case Studies – LM124 Validating the SPICE Model for the LM124
“R1”
Case Studies – LM124 Validating the SPICE Model for the LM124 4
Amplitude (V)
3
2
1
0
-1 -10
-8
-6
-4
-2
0
2
4
6
8
10
Time (µ µs)
Heavy Ion
Pulsed Laser
72
Case Studies – LM124 Validating the SPICE Model for the LM124 V+ Q16
Q15 Q14
Q19 Vin(+) C1
Q12
Q18 Q20 Vin(-)
Q13
R2 Q7
R1
Vout
Q6 Q11
Q17 Q21
Q9 Q5
Q2 Q3
Q8
Q10
Q4
V-
Case Studies – LM124 Validating the SPICE Model for the LM124 SPICE
R1 has a transistor structure but the base is left floating and so it acts as a resistor.
Pease, SEE Symposium 2004
73
Long-Duration Pulses (LDPs)
Case Studies ASET width determined by device bandwidth. OP293
LMH6628 4.5 4
300 us
Ampltiude (V)
3.5 3
30 ns
2.5 2 1.5 1 0.5 0 0
50
100
150
200
250
300
350
400
Time (ns)
Unity gain bandwidth = 35 kHz
Unity gain bandwidth = 300 MHz
74
Case Studies – LM6144 Long-Duration Pulses observed in Heavy-Ion Testing of LM6144 Op-Amp.
Unity-gain bandwidth - 17 MHz (∆t < 1µs)
Only observed for LETs > 50 MeV.cm2/mg
Boughassoul et al. IEEE TNS 2004
Case Studies – LM6144 Laser Scan identified the origins of the LDPs
-9 V to –9.25 V
9.2 V to 9.8 V
Boughassoul et al. IEEE TNS 2004
75
Case Studies – LM6144 Laser Scan identified the origins of the LDPs Effect of light: • Illuminator • Scattered laser light • Room lights Strikes to other transistors • Stops the transient LDPs (in dark) depend on supply voltage: Vdd = ± 10V, ∆t=25 ms Vdd = ± 7.5V, ∆t=45 ms Vdd = ± 5.0V, ∆t=100 ms Boughassoul et al. IEEE TNS 2004
Case Studies – LM6144 Used SPICE to model effects • Able to simulate all effects • Pulse Length vs supply voltage
Boughassoul et al. IEEE TNS 2004
76
Case Studies – LM6144 Used SPICE to model effects
• Suggested hardening approach – adding capacitors across C/B of two transistors in the bias/startup circuit.
Boughassoul et al. IEEE TNS 2004
6. ASET Mitigation
77
ASET Mitigation Approaches • Repeat the Measurement Housekeeping measurement can be repeated three times
•Device Level Epitaxial layers (SOI) to limit charge collection
• Circuit Level Low bandpass filter to remove ASETs
• Circuit/Subsystem Level Triple Modular Redundancy (TMR)
ASET Mitigation Triple Modular Redundancy Rin
Cin
Van Vonno, IEEE TNS 2001
Rin Cin
78
ASET Mitigation Minimum Input Overdrive for ASET-free Operation - Depends on Input Resistance and Capacitance 160
Cin = 0 pF
Input Overdrive (mV)
140 120
9V 15 V 30 V
100 80
9V Cin = 100 pF 15 V 30 V
60 40 20 0 0
20
40
60
80
Input Resistance (Kohms)
100
120 Van Vonno, IEEE TNS 2001
7. Summary & Conclusions
79
Summary & Conclusions Which LM139 Caused Reset on MAP? +5V
+5V R=1k
R=3.6k 2.9V
EEP_RESET (∆ ∆=2.5V) LM139
R=5.1k
Vref=2.5V HW_RESET (∆ ∆=2.5V)
+5V R=100k
2.9V LM139 Vref=2.5V
5V
R=1.5k C=10 µF
R=10k
LM139 Vref=2.5V Poivey RADECS 2002
Summary & Conclusions • ASETs have caused anomalies in spacecraft. • They occur in linear devices when particle radiation passes through a sensitive node. • A powerful approach for studying ASETs is to use a combination of simulation, broad-beam and focusedbeam of heavy ions, and pulsed laser light. • Linear devices are unique in that their ASET sensitivity depends on configuration. Testing in one condition does not automatically mean the data is valid for another condition. • There is many different approaches to reducing the ASET sensitivity of linear devices.
80