ASTM F773M-96(2003)

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Designation:F773M–96 (Reapproved 2003)
Standard Practice for
Measuring Dose Rate Response of Linear Integrated
Circuits (Metric)
This standard is issued under the fixed designation F773M; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope E668 Practice for Application of Thermoluminescence-
Dosimetry(TLD)SystemsforDeterminingAbsorbedDose
1.1 Thispracticecoversthemeasurementoftheresponseof
in Radiation-Hardness Testing of Electronic Devices
linear integrated circuits, under given operating conditions, to
F526 Test Method for Measuring Dose for Use in Linear
pulsed ionizing radiation.The response may be either transient
Accelerator Pulsed Radiation Effects Tests
or more lasting, such as latchup. The radiation source is either
a flash X-ray machine (FXR) or an electron linear accelerator
3. Terminology
(LINAC).
3.1 Definitions:
1.2 The precision of the measurement depends on the
3.1.1 dose rate—energy absorbed per unit time and per unit
homogeneity of the radiation field and on the precision of the
mass by a given material from the radiation to which it is
radiation dosimetry and the recording instrumentation.
exposed.
1.3 The test may be considered to be destructive either for
3.1.2 dose rate response—the change that occurs in an
further tests or for other purposes if the total radiation dose
observed characteristic of an operating linear integrated circuit
exceeds some predetermined level or if the part should latch
induced by a radiation pulse of a given dose rate.
up. Because this level depends both on the kind of integrated
circuit and on the application, a specific value must be agreed
4. Summary of Practice
upon by the parties to the test. (See 6.10.)
4.1 Thetestdeviceandsuitabledosimetersareirradiatedby
1.4 Setup,calibration,andtestcircuitevaluationprocedures
a pulse from either an FXR or a LINAC while the test device
are included in this practice.
is operating under agreed-upon conditions. The responses of
1.5 Procedures for lot qualification and sampling are not
the test device and of the dosimeters are recorded.
included in this practice.
4.2 The response of the test device to dose rate is recorded
1.6 Because response varies with different device types, the
over a specified dose rate range.
doseraterangeforanyspecifictestisnotgiveninthispractice
4.3 Anumber of factors are not defined in this practice, and
but must be agreed upon by the parties to the test.
must be agreed upon beforehand by the parties to the test.
1.7 This standard does not purport to address all of the
4.3.1 Total dose limit (see 1.3),
safety concerns, if any, associated with its use. It is the
4.3.2 Electrical parameters of the test device whose re-
responsibility of the user of this standard to establish appro-
sponses are to be measured (see 10.10),
priate safety and health practices and determine the applica-
4.3.3 Temperature at which the test is to be performed (see
bility of regulatory limitations prior to use.
6.7),
2. Referenced Documents 4.3.4 Details of the test circuit, including output loading,
2 power supply levels, and other operating conditions (see 7.4
2.1 ASTM Standards:
and 10.3),
4.3.5 Choice of radiation pulse source (see 6.9 and 7.9),
This practice is under the jurisdiction ofASTM Committee F01 on Electronics
4.3.6 Pulse width (see 6.9 and 7.9.2),
and is the direct responsibility of Subcommittee F01.11 on Nuclear and Space
4.3.7 Sampling (see 8.1),
Radiation Effects.
4.3.8 Need for total dose measurement (see 6.10, 7.8, and
Current edition approved June 10, 2003. Published June 2003. Originally
approved in 1982. Last previous edition approved in 1996 as F773M–96. DOI: 10.1.1),
10.1520/F0773M-96R03.
4.3.9 An irradiation plan which includes the dose rate range
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
andtheminimumnumberofdoseratevaluestobeusedinthat
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
range (see 10.6 and 10.9), and
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website.
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F773M–96 (2003)
4.3.10 Appropriate functional test (see 10.4 and 10.8). tion of the test device. Reasonable estimates of the expected
magnitudeofcurrentresultingfromsecondary-emissioneffects
5. Significance and Use
can be made based on the area of metallic target materials
5.1 There are many kinds of linear integrated circuits. Any irradiated.
givenlinearintegratedcircuitmaybeusedinavarietyofways
NOTE 1—For dose rates in excess of 10 Gy (Si)/s the photocurrents
and under various operating conditions within the limits of
developed by the package may dominate the device photocurrent. Care
performance specified by the manufacturer. The procedures of
should be taken in the interpretation of the measured photoresponse for
this practice provide a standardized way to measure the
these high dose rates.
dose-rate response of a linear integrated circuit, under operat-
Values of current density per unit dose rate generally range
ing conditions similar to those of the intended application,
−11 −10 2
between 10 and 10 A/cm per Gy/s. The use of a scatter
when the circuit is exposed to pulsed ionizing radiation.
plate (7.9.2) may increase these values.
5.2 Knowledge of the responses of linear integrated circuits
6.3 Orientation—The effective dose to a semiconductor
to radiation pulses is essential for the design, production, and
junction can be altered by changing the orientation of the test
maintenance of electronic systems that are required to operate
device with respect to the irradiating beam. Most integrated
in the presence of pulsed radiation environments.
circuits may be considered “thin samples” (in terms of the
6. Interferences range of the radiation). However, some devices may have
cooling studs or thick-walled cases that can act to scatter the
6.1 Air Ionization—A spurious component of the signal
incident beam, thereby modifying the dose received by the
measured during a test can result from conduction through air
semiconductor chip. Position such devices carefully with the
ionizedbytheradiationpulse.Suchspuriouscontributionscan
die normal to the beam.
be checked by measuring the signal while irradiating the test
6.4 Dose Enhancement—High atomic number materials
fixture in the absence of a test device.Air ionization contribu-
near the active regions of the integrated circuit (package,
tions to the observed signal are generally proportional to
metallization, die attach materials, etc.) can deliver an en-
applied field, while those due to secondary emission effects
hanced dose to the sensitive regions of the device when it is
(6.2)arenot.Theeffectsofairionizationexternaltothedevice
irradiatedwithanFXR.Thepossibilityandextentofthiseffect
may be minimized by coating exposed leads with a thick layer
should be considered.
of paraffin, silicone rubber, or nonconductive enamel, or by
making the measurement in a vacuum. 6.5 Electrical Noise—Since radiation test facilities are in-
6.2 Secondary Emission —Another spurious component of herent sources of r-f noise, good noise-minimizing techniques
the measured signal can result from charge emission from, or such as singlepoint ground, filtered dc supply lines, etc., must
charge injection into, the test device and test circuit. This may be used in these measurements (see Fig. 1).
be minimized by shielding the surrounding circuitry and
6.6 Dosimetry—Accurate, reproducible calibration of dose-
irradiating only the minimum area necessary to ensure irradia-
rate monitors is difficult. For this reason, dosimetry is apt to
provide the single most substantial source of error in dose-rate
determinations.
Sawyer, J.A., and van Lint, V.A. J., “Calculations of High-Energy Secondary
6.7 Temperature—Device characteristics are dependent on
Electron Emission,” Journal of Applied Physics , Vol 35, No. 6, June 1964, pp.
junction temperature; hence, the temperature of the test should
1706–1711.
FIG. 1 Example of a Test Circuit
F773M–96 (2003)
be controlled. Unless otherwise agreed upon by the parties to required by the test device during the radiation pulse. Its value
the test, measurements will be made at room temperature (23 must be large enough that the decrease in the supply voltage
6 5°C). during a pulse is less than 10%. Capacitor C should be
6.8 Beam Homogeneity and Pulse-to-Pulse Repeatability— paralleled by a small (approximately 0.1 µF) low-inductance
The intensity of a beam from an FXR or a LINAC is likely to capacitor, C , to ensure that possible inductive effects of the
vary across its cross section. Since the pulse-shape monitor is large capacitor are offset. Both capacitors must be located as
placed at a different location than the device under test, the close to the test device as possible, consistent with the space
measured dose rate may be different from the dose rate to needed for any shielding that may be necessary. The arrange-
which the device was exposed. The spatial distribution and ment of the grounding connections provides that no ground
intensity of the beam may also vary from pulse to pulse. The loops and only one ground exists. This reduces both the
beam homogeneity and pulse-to-pulse repeatability associated possibility of ground loops and common-mode signals present
with a particular radiation source should be established by a at the terminals of the measurement instruments.The resistors,
thorough characterization of its beam prior to performing a R , are terminations for the coaxial cables, and have values
measurement. within 2% of the characteristic impedances of their respective
6.9 Pulse Width—The response observed in a dose rate test cables. All unused inputs to the test device are connected as
maybedependentonthewidthoftheradiationpulse.Thisfact agreed upon by the parties to the test. The output(s) of the test
must be considered when selecting a radiation source, or when devicemaybeloaded,asagreeduponbythepartiestothetest.
comparingdatatakenatdifferenttimesoratdifferentradiation To prevent loading of the output of the test device by the
test facilities. coaxial cable, line drivers having a high input impedance and
6.10 Total Dose—Eachpulseoftheradiationsourceimparts adequatebandwidth,linearity,anddynamicrangemaybeused
a dose to both the device under test and the device used for to reproduce accurately at the output end of the coaxial cable
dosimetry. The total dose accumulated in a semiconductor the waveforms appearing at the line driver inputs.
device will cause permanent damage which can change its 7.5 Signal Sources, as required to provide the agreed-upon
operating characteristics. As a result, the response that is operating conditions of the test device and to perform suitable
measured after several pulses may be different from that functional tests.
characteristic of an unirradiated device. Care should be exer- 7.6 Radiation Pulse-Shape Monitor—One of the following
cisedtoensurethatthetotaldosedeliveredtothetestdeviceis todevelopasignalproportionaltothedoseratedeliveredtothe
less than the agreed-upon maximum value. Care must also be test device.
taken to ensure that the characteristics of the dosimeter have 7.6.1 Fast Signal-Diode in the circuit configuration of Fig.
not changed due to the accumulated dose. 2.Theresistors,R ,serveashighfrequencyisolationandmust
be at least 20 V. The capacitor, C (typically 10 µF), supplies
the charge during the current transient; its value must be large
7. Apparatus
enough that the decrease in voltage during a current pulse is
7.1 Regulated DC Power Supplies with floating outputs to
less than 10%. Capacitor C should be paralleled by a small
produce the voltages required to bias the integrated circuit
(approximately0.1µF)low-inductancecapacitor,C ,toensure
under test.
that possible inductive effects of the large capacitor are offset.
7.2 Recording Devices,suchasoscilloscopesequippedwith
The resistor, R , is to provide the proper termination (within
cameras,transientdigitizerswithappropriatedisplays,orother
62%)forthecoaxialcableusedforthesignallead.Thisisthe
suitable instruments.The bandwidth capabilities of the record-
preferred apparatus for this purpose.
ing devices shall be such that the radiation responses of the
7.6.2 P-I-N Diode in the circuit configuration of Fig. 2
integrated circuit and the pulse-shape monitor (7.6) are accu-
(7.6.1).Careshouldbetakentoavoidsaturationeffectsathigh
rately displayed and recorded.
dose rates and R-C charging effects at low dose rates.
NOTE 2—Depending on the kind of measurement, dc instruments,
7.6.3 Current Transformer, mounted on a collimator at the
spectrum analyzers, current transformers, or other instruments may be
output window of the linear accelerator so that the primary
required to measure and record the response of the test device.
electron beam passes through the opening of the transformer
7.3 Cabling to complete adequately the connection of the
after passing through the collimator. The current transformer
test circuit in the exposure area with the power supply and
recording devices in the data area. Shielded twisted pair or
coaxialcablesmaybeusedtoconnectthepowersuppliestothe
bias points of the test circuit; however, coaxial cables properly
terminated at the recording device inputs are required for the
signal leads.
7.4 Test Circuit, as shown in Fig. 1.Although the details of
test circuits for this test must vary depending on the kind of
electronic component tested and on the specific electrical
parameters of the test device to be measured, the example of
Fig. 1 provides the information necessary for the design of a
test circuit for most purposes. The capacitor, C (typically 10
µF), provides an instantaneous source of current as may be FIG. 2 Irradiation Pulse-Shape Monitor Circuit for Diodes
F773M–96 (2003)
must have a bandwidth that accurately displays the current 7.11 Temperature-Measuring Device to measure ambient
signal. The low frequency cutoff of some commercial current temperature in the vicinity of the device under test to 61°C.
transformers is such that significant droop may occur for pulse
8. Sampling
widths greater than 1 µs. Do not use a transformer for which
this droop is greater than 5% for the radiation pulse width
8.1 This method determines the properties of a single
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