ASTM F1893-98(2003)
(Guide)Guide for Measurement of Ionizing Dose-Rate Burnout of Semiconductor Devices
Guide for Measurement of Ionizing Dose-Rate Burnout of Semiconductor Devices
SIGNIFICANCE AND USE
The use of FXR radiation sources for the determination of high dose-rate burnout in semiconductor devices is addressed in this guide. The goal of this guide is to provide a systematic approach to testing for burnout.
The different type of failure modes that are possible are defined and discussed in this guide. Specifically, failure can be defined by a change in device parameters, or by a catastrophic failure of the device.
This guide can be used to determine the survivability of a device, that is, that the device survives a predetermined level; or the guide can be used to determine the survival dose-rate capability of the device. However, since this latter test is destructive, the minimum dose-rate level for failure must be determined statistically.
SCOPE
1.1 This guide defines the detailed requirements for testing microcircuits for short pulse high dose-rate ionization-induced failure. Large flash x-ray (FXR) machines operated in the photon mode, or FXR e-beam facilities are required because of the high dose-rate levels that are necessary to cause burnout. Two modes of test are possible (1) survival test, and (2) A failure level test.
1.2 The values stated in International System of Units (SI) are to be regarded as standard. No other units of measurement are included in this standard.
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Designation:F1893–98 (Reapproved2003)
Guide for
Measurement of Ionizing Dose-Rate Burnout of
Semiconductor Devices
This standard is issued under the fixed designation F1893; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A
superscript epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope 3.1.2.1 Discussion—This effect strongly depends on the
mode of operation and bias conditions. Temperature may also
1.1 This guide defines the detailed requirements for testing
be a factor in damage to the device should latchup occur prior
microcircuits for short pulse high dose-rate ionization-induced
to failure. Latchup is known to be temperature dependent.
failure. Large flash x-ray (FXR) machines operated in the
3.1.3 failure condition—a device is considered to have
photon mode, or FXR e-beam facilities are required because of
undergone burnout failure if the device experiences one of the
the high dose-rate levels that are necessary to cause burnout.
following conditions.
Two modes of test are possible: (1) A survival test, and (2)A
(1) functional failure—a device failure where the device under
failure level test.
test, (DUT) fails the pre-irradiation functional tests following
1.2 The values stated in International System of Units (SI)
exposure.
are to be regarded as standard. No other units of measurement
(2) parametric failure—a device failure where the device
are included in this standard.
under test, DUT fails parametric measurements after exposure.
2. Referenced Documents
3.1.3.1 Discussion—Functional or parameteric failures may
becausedbytotalionizingdosemechanisms.Seeinterferences
2.1 ASTM Standards:
for additional discussion.
E666 PracticeforCalculatingAbsorbedDoseFromGamma
3.1.4 survival test—A “pass/fail” test performed to deter-
or X Radiation
mine the status of the device after being exposed to a
E668 Practice for Application of Thermoluminescence-
predetermined dose-rate level. The survival test is usually
Dosimetry(TLD)SystemsforDeterminingAbsorbedDose
considered a destructive test.
in Radiation-Hardness Testing of Electronic Devices
3.1.5 burnout level test—a test performed to determine the
3. Terminology
actual dose-rate level where the device experiences burnout.
3.1.5.1 Discussion—In such a test, semiconductor devices
3.1 Definitions:
are exposed to a series of irradiations of differing dose-rate
3.1.1 dose rate—energy absorbed per unit time per unit
levels. The maximum dose rate at which the device survives is
mass by a given material that is exposed to the radiation field
determined for worst-case bias conditions. The failure level
(Gy/s, rd/s).
test is always a destructive test.
3.1.2 high dose-rate burnout—permanent damage to a
semiconductor device caused by abnormally large currents
4. Summary of Guide
flowing in junctions and resulting in a discontinuity in the
4.1 Semiconductor devices are tested for burnout after
normal current flow in the device.
exposure to high ionizing dose-rate radiation. The measure-
ment for high-dose-rate burnout may be a survival test con-
ThisguideisunderthejurisdictionofCommitteeF01onElectronics,andisthe
sisting of a pass/fail measurement at a predetermined level; or
direct responsibility of Subcommittee F01.11 onNuclear and Space Radiation
itmaybeafailureleveltestwheretheactualdose-ratelevelfor
Effects.
burnout is determined experimentally.
Current edition approved Dec. 1, 2003. Published July 1998. DOI: 10.1520/
F1893-98R03.
4.2 The following quantities are unspecified in this guide
For referenced ASTM standards, visit the ASTM website, www.astm.org, or
and must be agreed upon between the parties to the test:
contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
4.2.1 The maximum ionizing (total dose to which the
Standards volume information, refer to the standard’s Document Summary page on
the ASTM website. devices will be exposed, and
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.
F1893–98 (2003)
4.2.2 Themaximumhighdoseratetowhichthedeviceswill 6.5.1 Input Bias—Unless otherwise specified, the input bias
be exposed. condition shall be chosen to provide the worst-case operating
conditions. For example, for digital devices, input pins that are
5. Significance and Use in the high state should be tied directly to the supply voltage.
For analog devices, input voltages generally should be at the
5.1 The use of FXR radiation sources for the determination
maximum levels expected to be used. For both digital and
of high dose-rate burnout in semiconductor devices is ad-
analog devices, it is desirable to perform the burnout test using
dressed in this guide. The goal of this guide is to provide a
at least two different input conditions, such as minimum input
systematic approach to testing for burnout.
levels and maximum input levels, or alternately with half the
5.2 The different type of failure modes that are possible are
inputs tied high and the remaining tied low.
defined and discussed in this guide. Specifically, failure can be
6.5.2 Output Loading—Unless otherwise specified, the
defined by a change in device parameters, or by a catastrophic
DUT outputs shall be chosen to provide the worst-case
failure of the device.
conditions for device operation. For digital devices, worst case
5.3 This guide can be used to determine the survivability of
conditions should include maximum fan-out. For analog de-
adevice,thatis,thatthedevicesurvivesapredeterminedlevel;
vices, worst-case conditions should include maximum output
or the guide can be used to determine the survival dose-rate
voltage or load current. For both digital and analog devices, it
capability of the device. However, since this latter test is
may be desirable to perform the burnout test using at least two
destructive, the minimum dose-rate level for failure must be
different output conditions.
determined statistically.
6.5.3 Operating Voltage—Unless otherwise specified, test-
ingshallbeperformedusingmaximumoperatingvoltages.The
6. Interferences
test setup shall be configured such that the transient power
6.1 There are several interferences that need to be consid-
supply photocurrent shall not be limited by the external circuit
ered when this test procedure is applied.
resistance or lead inductance. Power supply stiffening capaci-
6.2 Ionizing Dose Damage—Devices may be permanently
tors shall be included to keep the power supply voltage from
damaged by the accumulation of ionizing dose. This limits the
varying more than 10 % of the specified value during and after
number of radiation pulses that can be applied during burnout
the radiation pulse.
testing. The ionizing dose sensitivity depends on fabrication
6.6 Over-Stress—The high dose-rate burnout test should be
techniques and device technology. Metal oxide, semiconductor
considered destructive. Peak photocurrents in excess of 2 to 3
(MOS) devices are especially sensitive to ionizing dose dam-
amperes can occur during these tests. These large currents can
age, however, bipolar devices with oxide-isolated sidewalls
produce localized metalization, or semiconductor melting that
may also be affected by low levels of ionizing dose. The
is not readily detected by electrical testing, or both, but may
maximum ionizing total dose exposure of the test devices must
adversely affect device reliability. Devices that exceed manu-
not exceed fifty percent (50 %) of the typical ionizing dose
facturer’s absolute limits for current or power during burnout
failure level of the specific part type to ensure that a device
testing should not be used in high-reliability applications.
failure is caused by burnout, and not by an ionizing total dose.
6.7 Test Temperatures—Testing shall be performed at am-
6.2.1 Radiation Level Step Size—The size of the steps
bient temperature, or at a temperature agreed upon between the
between successive radiation levels limits the accuracy of the
parties to the test. If testing is performed in a vacuum,
determination of the burnout failure level.
overheating may be an issue, and temperature control is
6.3 Latchup—Some types of integrated circuits are suscep-
required.
tible to latchup during transient radiation exposure. If latchup
7. Apparatus
occurs, the device will not function correctly until power is
temporarily removed and reapplied. Permanent damage (burn-
7.1 General—The apparatus used for testing should include
out) may also occur during latchup, primarily caused by a
as a minimum, the radiation source, dosimetry equipment, a
substantial increase in power supply current that leads to
test circuit board, line drivers, cables and electrical instrumen-
increased power dissipation, localized heating, or both.
tation to measure the transient response, provide bias, and
Latchup is temperature dependent and testing at elevated
perform functional tests. Precautions shall be observed to
temperature is required to establish worst-case operating con- obtain an electrical measurement system with ample shielding,
ditions for latchup. Latchup testing is addressed elsewhere.
satisfactory grounding, and low noise from electrical interfer-
6.4 Charge Build-up Damage—Damage to a device may ence or from the radiation environment.
occurduetodirectelectronirradiationoftheDUTleads.When
7.1.1 Radiation Source—The most appropriate radiation
using direct electron irradiation of the DUT leads. When using source for high dose-rate burnout testing is a FXR machine.
direct electron irradiations, (see Section 7), all device leads
The required dose rate for burnout cannot usually be achieved
must be shielded from the electron beam to reduce charge using an electron linear accelerator (LINAC) because LINACs
pickup that could cause abnormally large voltages to be
typically cannot produce a sufficiently high dose rate over the
generated on internal circuitry and produce damage not related critical active area of the device under test. Linear accelerators
to ionizing dose-rate burnout.
shall be used only with agreement of all parties to the test.
6.5 Bias and Load Conditions—The objective of the test is 7.1.2 Flash X-ray (Photon Mode)—The choice of facilities
to determine the dose-rate survivability of the test devices depends on the available dose rate as well as other factors
when tested under worst case conditions. including photon spectrum, pulse width and end-point energy.
F1893–98 (2003)
The selection of the pulse width is affected by; (a), the dose isolation. A typical thermal decay time constant for such a
rate required, and (b), the ionizing dose accumulation per system is about 3 to 4 s and typical sensitivities are about 1000
pulse. Finally, the FXR end-point energy for the photon made
to 1500 rd(Si)/µV.
must be greater than 1 MeV to ensure device penetration.
7.2.3 PIN Diodes—APIN diode is the solid state equivalent
7.1.3 Flash X-ray (E-beam Mode)—An FXR operated in
of an ionization chamber. The magnitude of photo-charge
the e-beam mode generally provides a higher dose rate than
generated and collected in a back-biased diode is directly
similar machines operated in the photon mode. However,
proportional to the absorbed dose. Since the generation rate for
9 9
testing in the e-beam mode requires that appropriate precau-
silicon is 4.3 3 10 . . . rd(Si), 4.3 3 10 carrier pairs/rd (Si),
tions be taken and special test fixtures be used to ensure
these devices can be calibrated knowing only the detector
meaningful results. The beam produces a large magnetic field,
geometry.CalibrationdependsonthePINbiasandmaychange
which may interfere with the instrumentation, and can induce
with accumulated exposure. Most PIN diodes have a linear
large circulating currents in device leads and metals.The beam
response up to a dose rate of approximately 1 3 10 rd(Si)/s.
also produces air ionization, induced charge on open leads, and
(Warning—Care must be taken when using PIN diodes to
unwanted cable currents and voltages. E-beam testing is
ensure that the indicated PIN dose rate is equivalent to that
generally performed with the DUT mounted in a vacuum to
absorbedbytheDUT.Factorsthatcanaffectdosimetryinclude
reduce air ionization effects. Special dosimetry techniques are
theFXRphotonspectrum,themethodusedtocalibratethePIN
required to ensure propermeasurementofthedose.Finally,the
diode, and the location of the PIN diode relative to the DUT.)
FXR endpoint energy must be greater than 2 MeV to ensure
7.2.4 Opti-chromic Dosimeters—Opti-chromic dosimeters
device penetration. some necessary precautions are:
have many of the same advantages asTLDs.These devices are
7.1.3.1 The electron beam must be constrained to the region
relatively small, passive, inexpensive, and retain accurate dose
that is to be irradiated. Support circuits and components must
information for months between irradiation and measurement
be shielded.
of dose. The useful dose range of these devices is 400rd(Si) to
7.1.3.2 The electron beam must be stopped within the test
20Krd(Si). The device response is nearly linear with dose.
chamberandreturnedtotheFXRtopreventunwantedcurrents
Opti-chromic dosimeters are calibrated in a Co cell using
in cables and secondary radiation in the exposure room.
NISTtraceableexposures.Thedoseresponseisindependentof
7.1.3.3 All cables and wires must be protected from expo-
dose rate up to 10 rd(Si)/s.
sure to prevent extraneous currents. These currents may be
7.3 Test Circuit—The test circuit shall contain the device
caused by direct deposition of the beam in cables, or by
under test, wiring, and auxiliary components as required. It
magnetic coupling of the beams into the cable.
shall allow the application of power and bias signals at the
7.1.3.4 All cables and cable entries must be shielded from
device inputs and outputs. Power supply stiffening capacitors
electromagnetic radiation caused by the firing of the FXR
shall be included to keep the power supply voltage from
machine.
changingmorethan10 %ofitsspecifiedvalueduringandafter
7.1.3.5 An evacuated chamber for the test is required to
the radiation pulse (see 8.4). Capacitors placed across the
reduce the effects of air ionization.
supplyvoltageshallbelocatedasclosetotheDUTaspossible,
7.2 Dosimetry Equipment—Dosimetry equipment shall in-
but shall not be exposed to the radiation beam. The test circuit
clude the following:
shall allow the device under test to be tested under worst case
(a) a system for measuring ionizing dose, such as a
thermoluminescent dosimeter (TLD) or calorimeter, conditions (see 6.4).
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