Transcript Characterization of laser diodes for analog parallel

Radiation damage and annealing in
1310nm InGaAsP/InP lasers
for the CMS Tracker
K. Gill, G. Cervelli, R. Grabit, F. Jensen, and F. Vasey.
CERN, Geneva
August 2000
Background

CMS Tracker readout and control project




Complex system with >50000 optical links
Harsh radiation environment
Extensive use of commercial off-the-shelf components (COTS)
Part-of series of on-going validation tests required
before components integrated into final system

Previous tests reported at SPIE and RADECS 97- 99
SPIE 4134-22 - Karl Gill et al, August 2000
CMS Tracker optical link technology
MT
Tx

single-mode fibre + array connectors

Transmitter
Fibres and connectors
Receivers
Electronics

COTS issues:



MT

lasers

MT
radiation damage:
 reliability:
Rx
photodiodes
- 1310nm InGaAsP edge-emitter
- single-mode Ge-doped fibre
- InGaAs p-i-n photodiode
- rad-hardened 0.25mm in radiation zones
up to 1014particles/cm2 + 100 kGy
10 year lifetime in radiation environment
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CMS Experiment
SPIE 4134-22 - Karl Gill et al, August 2000
CMS Tracker radiation environment

charged hadrons (p, p, K)
SPIE 4134-22 - Karl Gill et al, August 2000
(courtesy M. Huhtinen, CERN)
CMS Tracker readout and control links
Analogue Readout
50000 links @ 40MS/s
Detector Hybrid
APVamplifiers
Tx Hybrid
MUX
2:1
96

pipelines
128:1 MUX
12
FED
Rx Hybrid
12
PLL Delay DCU
Timing
A
D
C
processing
buffering
DAQ
TTCRx
TTC
Control
CCU
Digital Control
2000 links @40MHz

FEC
6
TTCRx
CCU
8
processing
buffering
CCU
CCU
Front-End
SPIE 4134-22 - Karl Gill et al, August 2000
Back-End
System specifications

Analogue readout links
operational
specifications
Number of channels
Rise / fall time
Crosstalk
electrical
specifications
Max. input current
Threshold current
Forward voltage
Reverse voltage
optical
specifications
Wavelength
Max output power
Slope efficiency
Relative non-linearity
RIN
min
typ
1
max
12
2
unit
specification
in/
meas
out
ns
min
min
60
typ
100
10
max
15
1.5
2
min
typ
max
1260
500
1310
1000
.06
1
-130
1360
unit
specification
in/out meas
mA
mA
V
V
unit
nm
µW
W/A
%
dB/Hz
SPIE 4134-22 - Karl Gill et al, August 2000
specification
in/out meas

Last 2 columns
filled in for each
device type after
testing
Objectives

Compare damage from different particles


Measure annealing characteristics


0.8MeV n and 6MeV n, 330MeV p, 24GeV p, 60Co g
Temperature and current dependence
Make prediction for damage expected in CMS tracker

10 years at -10°C, including LHC luminosity profile
SPIE 4134-22 - Karl Gill et al, August 2000
Experiment

Devices

Italtel/NEC 1310nm edge-emitting InGaAsP/InP MQW lasers
 mounted on Si-submounts
 compact mini-DIL packages, single-mode fiber pigtails
 no other components in the package, e.g. lenses

Pre-irradiation characteristics at 20°C :
 Laser threshold currents 8-13mA
 Output efficiencies (out of the fibre) 30-70mW/mA

This type of device previously studied
 6MeV n, 330MeV p, 24GeV p, 60Co g
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DCPBH-MQW lasers

double-channel-planarburied-heterostructure
laser
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Test Procedures

Test A: Irradiate 0.8MeV n - compare damage with other
particles
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

Test B: Irradiate 0.8MeV n - anneal at different T
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

4 lasers, irrad room T, biased 5-10mA above threshold, 1015n/cm2 in 6.5 hrs.
Anneal at room T, biased 5-10mA above threshold for 115 hrs
12 lasers, cooled -13°C, unbiased, 1015n/cm2 in 6.3 hrs.
Anneal in groups of 3 at 20, 40, 60, 80°C for 300 hrs.
Test C: Irradiate 0.8MeV n - anneal at different bias currents


8 lasers, irrad room T, unbiased, 1015n/cm2 in 6.5 hrs.
Anneal in groups of 2 at 0, 40, 60, 80mA bias for 115 hrs.
SPIE 4134-22 - Karl Gill et al, August 2000
Test setup for in-situ measurement
of radiation damage and annealing
Irradiation
Source or
oven
Control room
photodetector
signal
Mac + Labview
optical fibre
Datalogger
Unit
Iout
laser
under
test
I generator
current
I/O register
Vin
Vout
DAC
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MUX + DMM
set V
threshold increase, Ithr (mA)
Test A - 0.8MeV irradiation at room T
10
8
6
LD1
LD2
LD3
LD4
4
2
0
0
2
4
6
8
10
14
2
0.75MeV neutron fluence, (10 n/cm )

Damage approximately linear with fluence
SPIE 4134-22 - Karl Gill et al, August 2000
threshold increase,  Ithr (mA)
Test A - Comparison with other particles
0.75MeV n
40
~6MeV n
0
330MeV p
30
24GeV p
0
+
Data averaged over
devices then normalized
to 96 hour irradiation
with 5x1014particles/cm2.
+
20
10
0
0
1
2
4
3
14
5
2
fluence,  (10 /cm )

Relative damage factors for 0.8MeV n with respect to
~6MeVn (1/3.1), 330MeV p (1/11.4), 24GeV p (1/8.4).
SPIE 4134-22 - Karl Gill et al, August 2000
threshold current (mA)
T (°C)
Test B - cooled irradiation
0
-5
-10
-15
20
Irradiation fluence
1015 (0.8MeV n)/cm2
irrad
16
annealing
12
8
4
0
5
10
15
20
25
30
35
40
time (hrs)

Test made at -10°C, then devices stored at -35°C
SPIE 4134-22 - Karl Gill et al, August 2000
unannealed fraction of defects
Test B - Annealing versus temperature
0.90
Devices split into
4 groups of 3 and
annealing at different
temperatures.
0.80
0.70
0.60
20°C
40°C
60°C
80°C
0.50
0.40
0.30
1

Threshold damage
assumed to be
proportional to number
of defects
10
100
annealing time (hours)
Annealing generally linear with log (time)
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remaining damage,  Ithr(t)/  Ithr(  )
Test C - Annealing versus current

Irradiation to 1015n/cm2
at room T, unbiased,
then anneal in 4 groups of 2
at different bias currents
0.90
0.80
Enhancement caused by:
0.70
(i) ‘recombination enhanced
annealing’ (?)
- supposed to be unlikely in
InGaAsP/InP
dc bias
0
40mA
60mA
80mA
0.60
0.50
1
10
annealing time, t (hrs)
100
(ii) thermal acceleration due
to power dissipation. At 80mA
Tjunction ~ 8C.
Up to factor 10 enhancement in terms of annealing time
SPIE 4134-22 - Karl Gill et al, August 2000
fraction of remaining defects, N( t ,t)/N( t ,0)
Annealing model

activation energy, E a (eV)
0.8
0.9
1.0
1.1
1.2
1.3
1.4
1.0
 Ea 
t  A exp 
 kT 
annealing time
t=0.1hr
t=1hr
t=10hr
t=100hr
t=1000hr
t=10000hr
0.8
0.6
0.4
remaining fraction of defects:
t max
0.0
10
0
2
4
10
10
10
time constant, t (hrs)
6
t

N( t )
  r(t)e t dt
N( ) tmin
A=1e-12
T=20°C
0.2
Assume 1st order (exponential)
annealing obeying Arrhenius law:
10
8
where
N()  k
For defects with a uniform distribution of activation energies
r = N/(tmax-tmin), the annealing is linear with log (time)
SPIE 4134-22 - Karl Gill et al, August 2000
Activation energy spectrum
unannealed fraction of defects
0.8
20°C
40°C
60°C
80°C
fit
0.7
0.6
Data points for each
group of 3 devices
averaged.
0.5
Fit annealing model
to Test B data.
0.4
A=1e-12, E a = 0.66 to 1.76 eV
0.3
1
10
100
annealing time (hrs)

Activation energy spectrum for best fit is 0.66<Ea<1.76eV
SPIE 4134-22 - Karl Gill et al, August 2000
Damage prediction in 1yr in CMS tracker
100
LHC/CMS running
80
damage + annealing
60
40
20
0
0
1000
2000
3000
4000
exposure time (hrs)

unannealed fraction of remaining defects
fraction of total defects in 1 year (% )
Use model to predict annealing of defects at -10°C over 1 LHC year
1.00
LHC shutdown
0.95
annealing
0.90
0.85
0.80
10
0
10
1
10
2
10
3
10
4
annealing time (hrs)
32% of total defects introduced during 1 year are annealed
SPIE 4134-22 - Karl Gill et al, August 2000
Damage prediction 10yrs in CMS tracker
damage (% 10yrs full luminosity)
Extend to 10 years, taking into
account LHC luminosity profile
80
total damage
annual components
60
Based on damage of 0.8MeV n at
-10C (Test B) and relative
damage factors (Test A),
possible to estimate damage to
laser threshold in CMS Tracker:
LHC luminosity
profile:
year 1: 10%
year 2, 33%
year 3, 66%
years 4-10, 100%
40
20
in worst case, at low radii (and
no bias-enhancement included),
0
0
2
4
6
8
LHC operating time (years)
SPIE 4134-22 - Karl Gill et al, August 2000
10
Ithr = 14mA
Conclusions

‘Calibrated’ damage from 0.8MeV neutrons


Determined annealing dependence
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
uniform distribution of activation energy 0.66<Ea<1.76eV
Based on data, applied model to CMS Tracker to predict
laser threshold damage


temperature and forward bias current
Constructed a model to describe the annealing v T


relative to 6MeV n, 330MeV p, 24GeV p
In the worst case, at low radii: Ithr = 14mA
Further work:

extension of the study to include lasers from other manufacturers.
SPIE 4134-22 - Karl Gill et al, August 2000