Datasheet - Excelitas

DATASHEET
Photon Detection
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Key Features
 High quantum efficiency: 77%
typical at 830 nm
 C30902SH and C30921SH can be
operated in Geiger mode
 C30902EH/SH-2 version with
built-in 905 nm filter
 C30902BH version with ball-lens
 Hermetically sealed package
 Low Noise at room temperature
 High responsivity – internal
avalanche gains in excess of 150
The C30902EH series of avalanche photodiodes is ideal for a wide range of applications,
including LIDAR, range-finding, small-signal fluorescence, photon counting and bar code
scanning.
Excelitas Technologies’ C30902EH series of avalanche photodiodes is fabricated
with a double-diffused “reach-through” structure. This structure provides high
responsivity between 400 and 1000 nm as well as extremely fast rise and fall times
at all wavelengths. The responsivity of the device is independent of modulation
frequency up to about 800 MHz. The detector chip is hermetically-sealed behind a
flat glass window in a modified TO-18 package. The useful diameter of the
photosensitive surface is 0.5 mm.
The C30921EH is packaged in a lightpipe TO-18 which allows efficient coupling of
light to the detector from either a focused spot or an optical fiber up to 0.25 mm in
diameter. The hermetically-sealed TO-18 package allows fibers to be mated to the
end of the lightpipe to minimize signal losses without fear of endangering detector
stability. The C30902EH-2 or C30902SH-2, with hermetic TO-18 package with inline
905nm passband filter and the C30902BH, with hermetic ball lens, complete the
C30902 family.
Both C30902SH and C30921SH are selected C30902EH and C30921EH photodiodes
having extremely low noise and bulk dark-current. They are intended for ultra-low
light level applications (optical power less than 1 pW) and can be used in either
their normal linear mode (Vr < Vbr) at gains up to 250 or greater, or as photon
counters in the “Geiger” mode (Vr > Vbr) where a single photoelectron may trigger
an avalanche pulse of about 108 carriers. In this mode, no amplifiers are necessary
and single-photon detection probabilities of up to approximately 50% are possible.
Photon-counting is also advantageous where gating and coincidence techniques are
employed for signal retrieval.
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 Spectral response range –
(10% Q.E. points) 400 to 1000 nm
 Time response – typically 0.5 ns
 Wide operating temperature
range -40°C to +70°C
 RoHS compliant
Applications
 LIDAR
 Range finding
 Small-signal fluorescence
 Photon counting
 Bar code scanning
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Table 1. Electro-optical Characteristics
Test conditions: Case temperature = 22˚C, unless otherwise specification, see notes on next page.
Detector Type
Parameter
Photosensitive area
active diameter
active area
Lightpipe characteristics (C30921)
Numerical aperture of light pipe
Index of refraction (n) of core
Core diameter
Field of view α (see Figure 15)
with standard/ball lens window
(-2) with built-in 905 nm filter
with lightpipe (in air)
Field of view α’ (see Figure 15)
with standard window/ball lens
(-2) with built-in 905 nm filter
Breakdown voltage, Vbr
Temperature coefficient of reverse bias,
Vr, voltage for constant gain
Detector Temperature (see note 2)
-TC
-DTC
Gain (see note 1)
Responsivity
at 830 nm (not applicable for -2)
at 900 nm
Quantum efficiency
at 830 nm (not applicable for -2)
at 900 nm
Dark current, id
-TC (at 0 °C)
-DTC (at -20 °C)
Noise current, in (see note 3)
-TC (at 0 °C)
-DTC (at -20 °C)
Capacitance
Rise/Fall time, RL=50 Ω
10% to 90% points
90% to 10% points
TEC maximal drive current
-TC
-DTC
TEC maximal bias voltage
-TC
-DTC
Dark count rate at 5% photon detection
probability (830 nm)
(see Figure 9 and note 4)
Voltage above Vbr for 5% photon
detection probability (830 nm)
(see Figure 7 and note 4)
After-pulse ratio at 5% photon detection
probability (830 nm) (note 5)
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C30902EH/C30902EH-2
C30902BH
C30921EH
Min
Typ
Max
0.5
C30902SH
C30902SH-2
C30921SH
Min
Typ
Max
Min
Typ
0.5
0.2
0.5
0.2
0.55
1.61
0.25
0.55
1.61
0.25
90
55
33
90
55
33
122
N/A
N/A
114
78
225
114
78
225
129
N/A
225
0.7
0.9
0.5
150
70
55
C30902SH-TC
C30902SH-DTC
77
65
117
92
0.7
0.5
0.2
Units
mm
mm²
[no units]
[no units]
mm
0.9
0.5
0.7
Degrees
Degrees
V
0.9
V/˚C
˚C
˚C
250
0
-20
250
128
108
128
108
A/W
A/W
30
77
60
15
2
1
0.2
77
60
15
30
77
60
15
0.23
0.5
0.11
1.6
2
1.6
2
0.04
0.02
1.6
0.5
0.5
0.75
0.75
0.5
0.5
0.75
0.75
0.5
0.5
5000
15000
2
2
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Max
15
1100 (-TC)
250 (-DTC)
2
%
%
nA
nA
nA
pA/Hz
pA/Hz
pA/Hz
pF
0.75
0.75
ns
ns
1.8
1.4
A
A
0.8
2.0
V
V
15000
cps
30
2
V
2
%
C30902 and C30921 Series-Rev.1-2014.09
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Notes:
1. At the specific DC reverse operating voltage, Vop or Vr,
supplied with each device and a light spot diameter of 0.25
mm (C30902EH, SH) or 0.10 mm (C30921EH, SH). Operated
at this voltage, between 180 and 250V, the device will meet
the electrical characteristic limits shown above.
2. The temperature of the thermistor in Kelvin can be
calculated using the following equation: [ ]
,
(
)
where
is the measured thermistor resistance in Ω,
,
,
and
3.
4.
5.
The theoretical expression for shot noise current in an avalanche photodiode is in =
(2q (Ids + (IdbM² + PORM) F) BW)½ where q is the electronic charge, Ids is the dark
surface current, Idb is the dark bulk current, F is the excess noise factor, M is the
gain, PO is the optical power on the device, and BW is the noise bandwidth. For
these devices F = 0.98 (2-1/M) + 0.02 M. (Reference: PP Webb, RJ McIntyre, JJ
Conradi, “RCA Review”, Vol. 35 p. 234, (1974)).
The C30902SH and C309021SH can be operated at a substantially higher detection
probability. (see Geiger Mode Operation section).
After-pulse occurring 1 µs to 60 seconds after main pulse.
.
Table 2 – Maximum Ratings
Parameter
Symbol Min Max Units
Storage temperature
Operating temperature
Soldering for 5 seconds (leads only)
Reverse current at room temperature
Average value, continuous operation
Peak value (1 s duration, non-repetitive)
TS
Top
Forward current at room temperature
Average value, continuous operation
Peak value (1 s duration, non-repetitive)
Maximum Total Power Dissipation
IF
-60
-40
100
70
200
°C
°C
°C
200
1
µA
mA
5
50
60
mA
mA
mW
Electro-Optical Characteristics
Figure 1 – Typical Spectral Responsivity at case temperature of 22 °C
1000
C30902EH/921EH
C30902SH/921SH
C30902EH-2
C30902SH-2
Responsivity [A/W]
100
10
1
400
500
600
700
800
900
1000
1100
Wavelength [nm]
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C30902 and C30921 Series-Rev.1-2014.09
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Figure 2 – Typical quantum efficiency vs. wavelength as a function of case temperature
100
-25 ⁰C
Quantum Efficiency [%]
25 ⁰C
10
1
500
550
600
650
700
750
800
850
900
950
1000
1050
Wavelength [nm]
Figure 3 – Typical responsivity @ 830nm vs. operating voltage as a function of case temperature
Responsivity [A/W]
1000
100
-40 ⁰C
10
+20 ⁰C
+60 ⁰C
1
140
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160
180
200
Bias Voltage [V]
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220
240
260
C30902 and C30921 Series-Rev.1-2014.09
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Figure 4 – Typical Noise current vs. Gain
Noise current [fA/√Hz]
1000
100
C30902EH
C30902SH
10
10
100
Gain, M [no units]
1000
Figure 5 – Typical dark current vs. operating voltage
Case temperature of 22 °C
1.E-06
Typical dark current [A]
C30902EH, C30921EH
C30902SH, C30921SH
1.E-07
1.E-08
150
160
170
180
190
200
210
220
230
DC operating voltage, Vop [V]
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C30902 and C30921 Series-Rev.1-2014.09
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Figure 6 – Typical Gain –Bandwidth Product as a function of Gain
Case temperature of 22 °C
400
Gain-Bandwidth product [GHz]
350
300
250
200
150
100
50
0
0
100
200
300
400
500
600
700
800
900
1000
Gain
Figure 7 – Geiger mode, photoelectron detection probability @ 830nm as a function of voltage above Vbr
Case temperature of 22 °C
Photoelectron detection probability (PDE) [%]
60
50
40
30
20
Ideal
Typical
10
0
0
5
10
15
20
25
Voltage above breakdown voltage (Vr - Vbr)
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C30902 and C30921 Series-Rev.1-2014.09
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Figure 8 – Load Line for C30921SH in the Geiger mode
500
High RL
450
Low RL
400
Conducting state (avalanching)
Dark current [mA]
350
300
250
Non-conducting state
(surface dark current only)
200
150
100
50
0
Vr
Vbr
Figure 9 – Typical Dark Count vs. Temperature at 5% Photon Detection Efficiency (830nm)
10000
Dark count [cps]
1000
100
10
-30
-25
-20
-15
-10
-5
0
5
10
15
20
25
30
Temperature [°C]
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C30902 and C30921 Series-Rev.1-2014.09
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Figure 10 – Probability of after-pulse within the next 100ns vs. delay-time in an active quenched circuit
(typical for C30902SH and C30921SH at Vbr, at a at case temperature of 22 °C)
Probability of after-pulsing [%]
100
10
1
0.1
50
100
150
200
Delay Time [ns]
250
300
350
Package Drawings (Other packages available upon request)
Figure 11 – C30902EH and C30902SH, reference dimensions shown in mm (inches)
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C30902 and C30921 Series-Rev.1-2014.09
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Figure 12 – C30921EH and C30921EH, package outline and cutaway of the lightpipe, reference dimensions
shown in mm [inches]
Figure 13 – C30902EH-2 and C30902SH-2 reference dimensions shown in mm [inches]
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C30902 and C30921 Series-Rev.1-2014.09
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Figure 14 – C30902BH, reference dimensions shown in mm
Figure 15– C30902SH-TC, C30902SH-DTC, TO-66 with flange package outline, reference dimensions shown
in mm (inches)
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C30902 and C30921 Series-Rev.1-2014.09
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Figure 16 – Approximate field of view – C30902 and C30921 Series
For incident radiation at angles
, the photosensitive surface is totally illuminated.
For incident radiation at angles
, but
, the photosensitive surface is partially illuminated
“- TC” and “- DTC” TE Cooled version
TE cooled APD can be used for different reason (Figure 15). Most applications benefits from a -TC (single) or -DTC (dual)
version for two reasons:
1. To reduce the thermal noise for very small signal detection as described previously. The -TC version has been design
to operate the APD down to 0C whereas the -DTC version can be operated at -20C when the ambient temperature is
22C.
2. To keep a constant APD temperature no matter the ambient temperature. Because APD breakdown voltage
decreases with a decrease of temperature, the TE cooler allows a single operating voltage. Also, this configuration
allows constant APD performance over an extended ambient temperature range.
The thermistor located inside the unit can be used to monitor the APD temperature and can be used to implement a TE cooler
feedback loop to keep the APD at a constant temperature or/and to implement a temperature compensation on the APD bias
voltage. A proper heat-sink is required to dissipate the heat generated by the APD and the TE cooler.
Custom Designs
Recognizing that different applications have different performance requirements, Excelitas offers a wide range of
customization of these APDs to meet your design challenges. Dark count selection, custom device testing and packaging are
among many of the application specific solutions available
Geiger mode operation
When biased above the breakdown voltage, an avalanche photodiode will normally conduct a large current. However, if the
current is such that the current is limited to less than a particular value (about 50A for these diodes), the current is unstable
and can switch off by itself. The explanation of this behavior is that the number of carriers in the avalanche region at any one
time is small and fluctuating wildly. If the number happens to fluctuate to zero, the current must stop. If subsequently
remains off until the avalanche pulse is retriggered by a bulk or photo-generated carrier.
The “S” versions are selected to have a small bulk-generated dark-current. This makes them suitable for low-noise operation
below VBR or photon-counting above Vbr in the Geiger mode. In this so-called Geiger mode, a single photoelectron (or
thermally-generated electron) may trigger an avalanche pulse which discharges the photodiode from its reverse operating
voltage Vr to a voltage slightly below VBR. The probability of this avalanche occurring is shown in Figure 7 as the
“Photoelectron Detection Probability” and as can be seen, it increases with reverse voltage V r. For a given value of Vr-Vbr, the
Photoelectron Detection Probability is independent of Temperature. To determine the Photon Detection Probability, it is
necessary to multiply the Photon Detection Probability by the Quantum Efficiency, which is shown in Figure 2. The Quantum
Efficiency also is relatively independent of temperature, except near the 1000 nm cut-off.
The “S” versions can be used in the Geiger mode using either “passive” or “active” pulse quenching circuits. The advantages
and disadvantages of each are discussed below.
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C30902 and C30921 Series-Rev.1-2014.09
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Passive-Quenching Circuit
The simplest, and in many case a perfectly adequate method of quenching a breakdown pulse, is through the use of a current
limiting load resistor. An example of such a “passive” quenching is shown in Figure 16. The load-line of the circuit is shown in
Figure 8. To be in the conducting state at Vbr two conditions must be met:
1.
2.
The Avalanche must have been triggered by either a photoelectron or a bulk-generated electron entering at the
avalanche region of the diode. (Note: holes are inefficient at starting avalanches in silicon.) The probability of an
avalanche being initiated is discussed above.
To continue to be in the conducting state a sufficiently large current, called the latching current I LATCH, must be passing
through the device so that there is always an electron or hole in the avalanche region. Typically in the C30902SH and
C30921SH, ILATCH = 50 A. For currents (Vr-Vbr)/RL, much greater than ILATCH, the diode remains conducting. If the
current (Vr-Vbr)/RL, is much less than ILATCH, the diode switches almost immediately to the non-conducting state. If
(Vr-Vbr)/RL is approximately equal to ILATCH, then the diode will switch at an arbitrary time from the conducting to the
non-conducting state depending on when the number of electrons and holes in the avalanche region statistically
fluctuates to zero.
When RL is large, the photodiode is normally conducting, and the operating point is at Vr-IDSRL in the non-conducting state.
Following an avalanche breakdown, the device recharges to the voltage Vr - IDSRL with the time constant RLC, where C is the
total device capacitance including stray capacitance. Using C = 1.6 pF and RL = 200 k a recharge time constant of 0.32 s is
calculated. The rise-time is fast, 5 to 50ns, and decreases as Vr - Vbr increases, and is very dependent on the capacitances of
the load resistors, leads, etc. The jitter at the half-voltage point is typically the same order of magnitude as the rise-time. For
timing purposes where it is important to have minimum jitter, the lowest possible threshold of the rising pulse should be used.
VR2 Output voltage [arb. units]
Figure 16 – Sample of passive quench circuit
0
200
400
600
800
1000
Time [ns]
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C30902 and C30921 Series-Rev.1-2014.09
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
Active-Quenching Circuit
Until the C30902SH is recharged, the probability of detecting another incoming photoelectron is relatively low. To avoid an
excessive dead-time when operating at a large voltage above Vbr, an “actively quenched” circuit can be used. The circuit
temporarily drops the bias voltage for a fraction of a microsecond following the detection of an avalanche discharge. This
delay time allows all electrons and holes to be collected, including most of those temporarily “trapped” at various impurity
sites in the silicon. When the higher voltage is reapplied, there are no electrons in the depletion region to trigger another
avalanche or latch the diode. Recharging can now be very rapid through a small load resistor. Alternatively, the bias voltage
can be maintained but the load resistor is replaced by a transistor which is kept off for a short time after an avalanche, and
then turned on for a period sufficient to recharge the photodiode.
Timing Resolution
For photon counting applications, the time of the TTL triggered pulse after detecting a photon, when plotted on a curve, and
with the FWHM averaged, is the timing resolution or time jitter. The jitter at the half-voltage point is typically the same order
of magnitude as the rise-time. For timing purposes where it is important to have minimum jitter, the lowest possible threshold
of the rising pulse should be used.
After-Pulsing
An after-pulse is an avalanche breakdown pulse which follows, and is induced by, a photon-generated pulse. An after-pulse is
8
usually caused by one of the approximately 10 carriers which pass through the diode during an avalanche. This electron or
hole is captured and trapped at some impurity site in the silicon, as previously described. When this charge-carrier is liberated,
usually in less than 100 ns but sometimes several milliseconds later, it may start another avalanche. The probability of an
after-pulse occurring more than one microsecond later is typically less than 1% at 2 volts above V br, using the circuit shown in
Figure 16.
After-pulsing increases with bias voltage. If it is necessary to reduce after-pulses, it is recommended that one keep Vr-Vbr low,
use an actively-quenched circuit with a long delay-line, or a passively-quenched circuit with a long RLC constant. Stray
capacitances must also be minimized. Electronic gating of the signal can be performed in certain situations. Should afterpulses be a serious complication in a particular application, operation below Vbr with a good amplifier might be considered.
Dark Current
“S” versions have been selected to have a low dark-count rate. Cooling to -25C can reduce this by a factor of about 50, since
the dependence of dark-count rate on temperature is exponential.
The dark-count increases with voltage following the same curve as the Photoelectron Detection Probability until a voltage
where after-pulsing is responsible for a feedback mechanism which dramatically increases the dark-count rate. This maximum
voltage is circuit dependent, and is not warranted other than the values listed on Table 1. In most cases, with a delay time of
300 ns, the diode can be used effectively at Vr up to Vbr + 25V.
The C30902 should not be forward biased or, when unbiased, exposed to strong illumination. These conditions result in a
greatly enhanced dark-count, which may require up to 24 hours returning to its nominal value.
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C30902 and C30921 Series-Rev.1-2014.09
C30902 and C30921 Series
High-speed solid state detectors for low light level applications
RoHS Compliance
The C30902 and C30921 series of avalanche photodiodes are designed and built to be fully compliant with the European Union
Directive 2011/65/EU – Restriction of the use of certain Hazardous Substances (RoHS) in Electrical and Electronic equipment.
Warranty
A standard 12-month warranty following shipment applies. Any warranty is null and void if the photodiode window has been
opened.
About Excelitas Technologies
Excelitas Technologies is a global technology leader focused on delivering innovative, customized solutions to meet the
lighting, detection and other high-performance technology needs of OEM customers.
Excelitas has a long and rich history of serving our OEM customer base with optoelectronic sensors and modules for more than
45 years beginning with PerkinElmer, EG&G, and RCA. The constant throughout has been our innovation and commitment to
delivering the highest quality solutions to our customers worldwide.
From aerospace and defense to analytical instrumentation, clinical diagnostics, medical, industrial, and safety and security
applications, Excelitas Technologies is committed to enabling our customers' success in their specialty end-markets. Excelitas
Technologies has approximately 3,000 employees in North America, Europe and Asia, serving customers across the world.
Excelitas Technologies
22001 Dumberry Road
Vaudreuil-Dorion, Quebec
Canada J7V 8P7
Telephone: (+1) 450 424 3300
Toll-free: (+1) 800 775 6786
Fax: (+1) 450 424 3345
[email protected]
Excelitas Technologies
GmbH & Co. KG
Wenzel-Jaksch-Str. 31
D-65199 Wiesbaden
Germany
Telephone: (+49) 611 492 430
Fax: (+49) 611 492 165
[email protected]tas.com
Excelitas Technologies Singapore, Pte. Ltd.
8 Tractor Road
Singapore 627969
Telephone: (+65) 6775 2022 (Main number)
Telephone: (+65) 6770 4366 (Customer Service)
Fax: (+65) 6778-1752
[email protected]
For a complete listing of our global offices, visit www.excelitas.com/locations
© 2014 Excelitas Technologies Corp. All rights reserved. The Excelitas logo and design are registered trademarks of Excelitas Technologies Corp. All other trademarks not owned by Excelitas Technologies or its
subsidiaries that are depicted herein are the property of their respective owners. Excelitas reserves the right to change this document at any time without notice and disclaims liability for editorial, pictorial or
typographical errors.
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C30902 and C30921 Series-Rev.1-2014.09