IEC TR 62396-8:2020

IEC TR 62396-8 ®
Edition 1.0 2020-04
TECHNICAL
REPORT
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Process management for avionics – Atmospheric radiation effects –
Part 8: Proton, electron, pion, muon, alpha-ray fluxes and single event effects
in avionics electronic equipment – Awareness guidelines
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IEC TR 62396-8 ®
Edition 1.0 2020-04
TECHNICAL
REPORT
colourcolour
insinsiidede
Process management for avionics – Atmospheric radiation effects –

Part 8: Proton, electron, pion, muon, alpha-ray fluxes and single event effects

in avionics electronic equipment – Awareness guidelines

INTERNATIONAL
ELECTROTECHNICAL
COMMISSION
ICS 03.100.50; 31.020; 49.060 ISBN 978-2-8322-8010-2

– 2 – IEC TR 62396-8:2020 © IEC 2020
CONTENTS
FOREWORD . 5
INTRODUCTION . 7
1 Scope . 8
2 Normative references . 8
3 Terms, definitions, abbreviated terms and acronyms . 8
3.1 Terms and definitions . 9
3.2 Abbreviated terms and acronyms . 10
4 Technical awareness . 12
4.1 Basic knowledge of atmospheric secondary particles . 12
4.2 Four typical hierarchies of faulty conditions in electronic equipment: Fault –
error – hazard – failure . 15
4.3 General sources of radiation . 18
4.3.1 General sources of terrestrial radiation . 18
4.3.2 Atmospheric radiation particles . 19
4.3.3 Spectra at the avionics altitude . 22
4.4 Particle considerations . 25
4.4.1 General . 25
4.4.2 Alpha particles . 25
4.4.3 Protons . 26
4.4.4 Muons and pions . 30
4.4.5 Low-energy neutrons . 32
4.4.6 High-energy neutrons . 33
4.5 Conclusion and guidelines . 43
Annex A (informative) CMOS semiconductor devices . 45
Annex B (informative) General description of radiation effects . 48
B.1 Radiation effects in semiconductor materials by a charged particle – Charge
collection and bipolar action . 48
B.2 Radiation effects by protons . 49
B.3 Radiation effects by low-energy neutrons . 51
B.4 Radiation effects by high-energy neutrons . 52
B.5 Radiation effects by heavy ions . 53
Bibliography . 54

Figure 1 – Cosmic rays as origin of single event effects . 13
Figure 2 – Initial stage of secondary particle production . 14
Figure 3 – Differential high-energy neutron spectrum at sea level in NYC . 14
Figure 4 – Long-term cyclic variation in neutron flux measured at Moscow Neutron
Monitor Center . 15
Figure 5 – Differential proton spectra originating from solar-minimum sun, from big
flares on the sun, and from the galactic core . 15
Figure 6 – Typical hierarchy of fault conditions: Fault-error-failure . 18
Figure 7 – Sources of atmospheric ionizing radiation: Nuclear reactions and radioactive
decay . 19
Figure 8 – Differential flux of secondary cosmic rays at avionics altitude (10 000 m)
above NYC sea level . 22
Figure 9 – Differential flux of terrestrial radiation at NYC sea level . 23

Figure 10 – Measured differential flux of high-energy neutrons at NYC sea level and at
avionics altitudes (5 000 m, 11 000 m and 20 000 m) . 24
Figure 11 – Cumulative flux of terrestrial radiation at avionics altitude above NYC sea

level 25
Figure 12 – Comparison of measured cross section of memory devices irradiated by
high-energy protons and neutrons . 27
Figure 13 – Simplified scheme of muon/pion irradiation system . 30
Figure 14 – Nuclear capture of cross section of cadmium isotopes . 32
Figure 15 – Neutron energy spectra of monoenergetic neutron beam facilities . 35
Figure 16 – Neutron energy spectra from radioisotope neutron sources . 35
Figure 17 – Simplified high-energy neutron beam source in a quasi-monoenergetic
neutron source . 37
Figure 18 – Neutron energy spectra of quasi-monoenergetic neutron beam facilities . 38
Figure 19 – Conceptual illustration of cross section data obtained by (quasi-)
monoenergetic neutron sources and fitting curve by Weibull fit . 39
Figure 20 – Simplified high-energy neutron beam source in a spallation neutron source . 41
Figure 21 – Neutron energy spectra of spallation neutron sources and terrestrial field . 42
Figure A.1 – Basic substrate structure used for CMOSFET devices on the stripe
structure of p- and n-wells and cross sections of triple and dual wells . 45
Figure A.2 – SRAM function and layout . 46
Figure A.3 – Example of logic circuit . 46
Figure A.4 – Example of electronic system implementation . 47
Figure A.5 – Example of stack layers in an electronic system . 47
Figure B.1 – Charge collection in a semiconductor structure by funnelling . 48
Figure B.2 – Bipolar action model in a triple well n-MOSFET structure . 49
Figure B.3 – Charge deposition density of various particles in silicon as a function of
particle energy . 50
Figure B.4 – Total nuclear reaction cross section of high-energy proton and neutron in
silicon . 50
Figure B.5 – Microscopic fault mechanism due to spallation reaction of high-energy
neutron and proton in a SRAM cell . 51
Figure B.6 – (n,α) reaction cross section of low-energy neutrons with B . 52
Figure B.7 – Calculated energy spectra of Li and He produced by neutron capture
10 7
reaction with B(n,α) Li reaction . 52
Figure B.8 – Ranges of typical isotopes produced by nuclear spallation reaction of
high-energy neutron in silicon . 53
Figure B.9 – Calculated energy spectra of elements produced by nuclear spallation
reaction of high-energy neutrons in silicon at Tokyo sea level . 53

Table 1 – General modes of faults . 17
Table 2 – Properties of atmospheric radiation particles . 19
Table 3 – Selected data sources for spectra of atmospheric radiation particles . 22
Table 4 – Non-exhaustive list of methods for alpha-particle SEE measurements . 26
Table 5 – Non-exhaustive list of facilities for proton irradiation . 27
Table 6 – Non-exhaustive list of facilities for muon irradiation . 31
Table 7 – Non-exhaustive list of facilities for thermal/epi-thermal neutron irradiation . 33

– 4 – IEC TR 62396-8:2020 © IEC 2020
Table 8 – Non-exhaustive list of facilities for low-energy neutron irradiation . 36
Table 9 – Non-exhaustive list of facilities for quasi-monoenergetic neutron irradiation . 40
Table 10 – Non-exhaustive list of facilities for nuclear spallation neutron irradiation . 42

INTERNATIONAL ELECTROTECHNICAL COMMISSION
____________
PROCESS MANAGEMENT FOR AVIONICS –
ATMOSPHERIC RADIATION EFFECTS –

Part 8: Proton, electron, pion, muon, alpha-ray fluxes and single event
effects in avionics electronic equipment – Awareness guidelines

FOREWORD
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The main task of IEC technical committees is to prepare International Standards. However, a
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data of a different kind from that which is normally published as an International Standard, for
example "state of the art".
IEC TR 62396-8, which is a Technical Report, has been prepared by IEC technical committee
107: Process management for avionics.

– 6 – IEC TR 62396-8:2020 © IEC 2020
The text of this Technical Report is based on the following documents:
Draft TR Report on voting
107/355/DTR 107/365/RVDTR
Full information on the voting for the approval of this Technical Report can be found in the
report on voting indicated in the above table.
This document has been drafted in accordance with the ISO/IEC Directives, Part 2.
A list of all the parts in the IEC 62396 series, published under the general title Process
management for avionics – Atmospheric radiation effects, can be found on the IEC website.
The committee has decided that the contents of this document will remain unchanged until the
stability date indicated on the IEC website under "http://webstore.iec.ch" in the data related to
the specific document. At this date, the document will be
• reconfirmed,
• withdrawn,
• replaced by a revised edition, or
• amended.
IMPORTANT – The 'colour inside' logo on the cover page of this publication indicates
that it contains colours which are considered to be useful for the correct understanding
of its contents. Users should therefore print this document using a colour printer.

INTRODUCTION
Atmospheric radiation can be responsible for causing single event effects (SEEs) in electronic
equipment. Beside neutrons and protons, there are other atmospheric radiation sources (for
example electrons, pions and muons), which are currently regarded as minor sources, which
can also affect electronics in avionics and terrestrial applications. This is currently a new
emerging topic with a limited amount of test data and supporting information.
This document, as part of the IEC 62396 series, provides awareness on this new emerging topic
in order to inform avionics systems designers, electronic equipment manufacturers and
component manufacturers and their customers of the kind of ionising radiation environment that
their electronic devices can be subjected to in aircraft and the potential effects this radiation
environment can have on those electronic devices.
This awareness is unavoidable due to the aggressive scaling of electronic semiconductor
devices to smaller and smaller transistor feature sizes where the impact of these radiation
sources can become visible or even significant in the future. For example, some evidence of
muon effects has appeared in the literature, in which the impact of muons seems to be negligible
at present. This document gives a comprehensive survey on the nature of these particles,
atmospheric spectra, induced phenomena and possible testing facilities with their radiation
sources; it also provides orientation in order to prepare avionics in the future.

– 8 – IEC TR 62396-8:2020 © IEC 2020
PROCESS MANAGEMENT FOR AVIONICS –
ATMOSPHERIC RADIATION EFFECTS –

Part 8: Proton, electron, pion, muon, alpha-ray fluxes and single event
effects in avionics electronic equipment – Awareness guidelines

1 Scope
This part of IEC 62396 is intended to provide awareness and guidance with regard to the effects
of small particles (that is, protons, electrons, pions and muon fluxes) and single event effects
on avionics electronics used in aircraft operating at altitudes up to 60 000 feet (18 300 m). This
is an emerging topic and lacks substantive supporting data. This document is intended to help
aerospace or ground level electronic equipment manufacturers and designers by providing
awareness guidance for this new emerging topic.
Details of the radiation environment are provided together with identification of potential
problems caused as a result of the atmospheric radiation received. Appropriate methods are
given for quantifying single event effect (SEE) rates in electronic components.
NOTE 1 The overall system safety methodology is usually expanded to accommodate the single event effects rates
and to demonstrate the suitability of the electronics for application at the electronic component, electronic equipment
and system level.
NOTE 2 For the purposes of this document the terms "electronic device" and "electronic component" are used
interchangeably.
Although developed for the avionics industry, this document can be used by other industrial
sectors at their discretion.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements of this document. For dated references, only the edition cited applies.
For undated references, the latest edition of the referenced document (including any
amendments) applies.
IEC 62396-1:2016, Process management for avionics – Atmospheric radiation effects – Part 1:
Accommodation of atmospheric radiation effects via single event effects within avionics
electronic equipment
3 Terms, definitions, abbreviated terms and acronyms
For the purposes of this document, the terms, definitions, abbreviated terms and acronyms
given in IEC 62396-1 and the following apply.
ISO and IEC maintain terminological databases for use in standardization at the following
addresses:
• IEC Electropedia: available at http://www.electropedia.org/
• ISO Online browsing platform: available at http://www.iso.org/obp

3.1 Terms and definitions
3.1.1
AND
logic gate which produces, in digital electronics, an output that is true (1) if both inputs are true
(1) and an output false (0) if neither or only one input is true (1)
3.1.2
bipolar action
phenomenon whereby some electrons or holes stay in the bulk of the semiconductor and switch
on the parasitic transistor to change the data states in memory elements
3.1.3
charge collection
part of electrons or holes pairs collected into storage nodes
Note 1 to entry: Electrons or holes are generated along with the trajectory of high-energy charged particles. This
phenomenon is called charge deposition.
3.1.4
linear energy transfer
LET
rate of decrease with distance of the kinetic energy of an ionizing particle, due to the ionization
caused by that particle
Note 1 to entry: LET describes the action of radiation into matter. It is related to stopping power which in nuclear
physics is defined as the retarding force acting on charged particles, typically alpha and beta particles, due to
interaction with matter, resulting in loss of particle energy.
2 −1
Note 2 to entry: LET is typically quantified in units of MeV·cm ·mg , to account for the density of the material
through which the particle travels.
3.1.5
multi-node transient
MNT
multiple transients (SETs) produced along with a high-energy charged particle or in an area
affected by bipolar action
3.1.6
negative-AND
NAND
logic gate which produces, in digital electronics, an output that is false (0) only if all its inputs
are true (1) and an output true (1) if one or both inputs are false (0)
[SOURCE: IEC 62239-1:2018, 3.1.22]
3.1.7
negative-OR
NOR
logic gate which produces, in digital electronics, an output that is true (1) if both the inputs are
false (0) and an output false (0) if one or both inputs are true (1)
[SOURCE: IEC 62239-1:2018, 3.1.23]
3.1.8
OR
logic gate which produces, in digital electronics, an output that is true (1) if one of both inputs
is true (1) and an output false (0) if neither input is true (1)

– 10 – IEC TR 62396-8:2020 © IEC 2020
3.1.9
soft error rate
SER
rate at which a device or system encounters or is predicted to encounter soft errors
Note 1 to entry: Usually, this is expressed as either the number of failures-in-time (FIT) or mean time between
failures (MTBF). The unit adopted for quantifying failures in time is called FIT, which is equivalent to one error per
billion hours of device operation. MTBF is usually given in years of device operation; to put it into perspective, one
FIT equals approximately 1 000 000 000 / (24 × 365,25) = 114 077 times more than one-year MTBF.
3.1.10
radiation induced leakage current
RILC
cumulative effect of ion-induced defects in capacitors with ultra-thin oxides
Note 1 to entry: This phenomenon can be noted in floating gate memory with thin oxide layers; data is stored
depending on the number of electrons in the floating gate. When a high-energy charged particle passes through the
tunnel oxide between the floating gate and source-drain channel underneath, a conduction path is created along the
path and stored electrons flow away, resulting in V shift or SEU.
th
3.1.11
(quasi-) monoenergetic neutron
neutron from a well-defined distribution of energies obtained by bombarding high-energy
charged particles at a thin metallic target
Note 1 to entry: Monoenergetic neutron beams have a single narrow flux peak at a particular neutron energy. All
the neutrons in the beam have energies at or close to the nominal energy.
Note 2 to entry: Quasi-monoenergetic neutron beams have a narrow flux peak at a nominal neutron energy and a
tail covering a broad range of energies below the nominal energy. Typically, about half the neutrons have energy
close to the nominal energy and about half are in the low-energy tail.
3.2 Abbreviated terms and acronyms
ANITA Atmospheric-like Neutrons from thick Target
BNCT boron neutron capture therapy
BNL Brookhaven National Laboratory (USA)
BOX buried oxide
BPSG boron phosphorus silicate glass (also named borophosphosilicate glass)
CAM content addressable memory
CEA / CVA Atomic Energy Commission / Centre of Valduc (France)
CEA / DIF Atomic Energy Commission / “Direction” of military applications Ile de France
(France)
CMOS complementary metal oxide semiconductor
CMOSFET complementary metal oxide semiconductor field effect transistor
CMP chemical mechanical polishing
CNL Crocker Nuclear Laboratory (USA)
CNRF Cold Neutron Research Facility
CPU central processing unit
CYRIC CYclotron and RadioIsotope Center (Tohoku University, Japan)
DD displacement damage
DICE dual interlocked storage cell
DMR double modular redundancy
DRAM dynamic random access memory
DUT device under test
ECC error correction code / error checking and correction
ECU electronic control unit
EEPROM electrically erasable programmable read-only memory
EMI electro-magnetic interference
FD fully depleted
FET field effect transistor
FF flip-flop
FIT failure in time
FNL Fast Neutron Laboratory (Tohoku University, Japan)
FPGA field-programmable gate array
GPU graphic processing unit
HKMG high-k metal gate
HLA hyper low alpha
IGBT insulated gate bipolar transistor
INC intra nuclear cascade
IUCF Indiana University Cyclotron Facility (USA)
J-PARC Japan Proton Accelerator Research Complex (Japan)
L1 / L2 level 1 / level 2 (related to microprocessor cache memories, "level 1" cache
memory being usually built onto the microprocessor device itself, “level 2” cache
memory being usually on a separate device or expansion card) [SOURCE:
IEC TR 62396-7:2017, 3.2]
L3 level 3 (related to, “level 3” cache memory being usually built onto the CPU
module or motherboard and working together with L1 and L2 cache memories
for improving processing performance
LANSCE Los Alamos National Science Center (USA)
LAMPF Los Alamos Meson Physics Facility (USA)
LBNL Lawrence Berkeley National Laboratory (USA)
LENS low-energy neutron source (university-based pulsed neutron source at IUCF)
LET linear energy transfer
MBU multiple bit upset
MCU multiple cell upset
MCBI multi-coupled bipolar interaction
MF masking factor
MNT multi-node transient
MOSFET metal oxide semiconductor field effect transistor
MTBF mean time between failures
NAND negative-AND
NIST National Institute of Standards and Technology (USA)
NMIJ National Metrology Institute (Japan)
NOR negative-OR
NPL National Physical Laboratory (UK)
NYC New York City
PCB printed circuit board
PD partially depleted
PDSOI partially depleted SOI
– 12 – IEC TR 62396-8:2020 © IEC 2020
PLL phase locked loop
QMN quasi-monoenergetic
RAM random access memory
RCNP Research Center for Nuclear Physics (Japan)
RILC radiation induced leakage current
ROM read only memory
SBU single bit upset
SEB single event burnout
SEE single-event effect
SEFI single event functional interrupts
SEGR single event gate rupture
SEL single event latch-up
SER soft error rate
SET single event transient
SEU single event upset
SIMS secondary ion mass spectrometry
SOI silicon on insulator
SRAM static random access memory
SRIM stopping and range of ions in matter (related to a collection of softwarepackages
STI shallow trench insulator
TAMU Texas A&M University (USA)
TID total ionization dose
TMR triple modular redundancy
TSL The Svedberg Laboratory (Uppsala university, Sweden)
ULSI ultra large scale integration
4 Technical awareness
4.1 Basic knowledge of atmospheric secondary particles
Primary cosmic rays, which are ionizing particles with extremely high energies, come from the
galactic core and the sun to the atmosphere of Earth, where they generate secondary cosmic
radiation. The atmospheric radiation environment under normal conditions is described in
IEC 62396-1; extreme space weather conditions, which can occur at times of high solar activity,
are described in IEC TR 62396-6. Here, an abbreviated description is given, based on terrestrial
radiation effects in ULSI electronic components and electronic systems, see [1] .
Primary cosmic rays in outer space consist mainly of protons. Cosmic rays are charged particles
so that they twine around lines of geomagnetic or heliomagnetic forces as illustrated by Figure 1.
Some are trapped by geomagnetic force to form the Van Allen radiation belt. Cosmic rays with
energies less than a geomagnetic rigidity cut-off tend to be deflected before entering the
atmosphere. Some are, on the other hand, attracted into geomagnetic poles along with lines of
geomagnetic force sometimes accompanied by aurorae. Cosmic rays are deflected rather
strongly near the equator since the lines of geomagnetic force are roughly parallel to the surface
of Earth. Therefore, the strength of cosmic rays that reach the atmosphere differs depending
on geomagnetic latitude.
___________
Numbers in square brackets refer to the Bibliography.

Figure 1 – Cosmic rays as origin of single event effects
When primary cosmic rays enter the atmosphere (troposphere and stratosphere) of Earth, some
particles induce spallation reaction in nuclei in the atmosphere (mainly nitrogen and oxygen
nuclei) to produce a number of secondary particles including electrons, muons, pions, protons
and neutrons as illustrated by Figure 2. Since secondary neutrons in the atmosphere have a
longer range than protons, they can cause cascades of spallation reactions in the atmosphere
to make air showers that can reach the surface of Earth. Figure 3 shows an estimated
differential neutron spectrum at the NYC sea level based on the measured data in JEDEC
JESD89 [2]. As the air can shield neutrons, the strength (flux and energy) of neutrons depends
upon altitude with a slight dependency on atmospheric pressure [3].
As cosmic rays are also deflected by the heliomagnetic field, which is affected by cyclic solar
activity for a period of around eleven years, the strength of neutrons on the ground also has an
eleven-year cycle as illustrated by Figure 4. At solar maximum, neutron intensity on the ground
is weakest, while it is the strongest at the solar minimum. Under normal activity, the sun emits
a large quantity of protons but their energies are relatively low, as shown in Figure 5 for solar
maximum conditions, as protons from the sun do not cause air showers on the ground. However,
when big flares take place on the sun’s surface, a much larger quantity of protons is emitted
with comparable energies to galactic protons and can cause air showers.

– 14 – IEC TR 62396-8:2020 © IEC 2020

Figure 2 – Initial stage of secondary particle production

Figure 3 – Differential high-energy neutron spectrum at sea level in NYC

Figure 4 – Long-term cyclic variation in neutron flux measured
at Moscow Neutron Monitor Center

Figure 5 – Differential proton spectra originating from solar-minimum sun,
from big flares on the sun, and from the galactic core
4.2 Four typical hierarchies of faulty conditions in electronic equipment: Fault – error
– hazard – failure
Electronic equipment can be disrupted by a range of radiation effects [4, 5, 6, 7, 8]. The types
of faults caused by atmospheric radiation are summarized in Table 1. Other types of faults are
not considered here. Radiation effects can be categorized as cumulative or random, the former
comprising effects due to total ionizing dose (TID) and displacement damage (DD); the latter
comprising single-event effects (SEEs), of which there are many types. Unlike in space, where
electronic equipment encounters high radiation doses from primary cosmic rays and trapped
radiation belts, avionics electronic equipment is normally only affected by SEEs, which are
equally likely at any time during the operational lifetime of a product, largely irrespective of the
accumulated dose.
– 16 – IEC TR 62396-8:2020 © IEC 2020
SEEs originate from spurious transient charge generation in an electronic device well or
substrate, caused by the passage of an energetic ionizing particle. Starting from such transients,
a kind of hierarchy of fault conditions can be considered as illustrated by Figure 6. When a fault
is captured and causes data flips in memory devices such as SRAMs, DRAMs, flash memories
and FFs, it is regarded as an error at the electronic device or circuit level. A fault does not
always cause an error, depending mainly on the location and the amount of charge collected
by an active node. When an error propagates to the final output of an electronic equipment and
causes malfunction of the electronic equipment, this consequence is called a failure. An
incorrect output of the electronic equipment is called a hazard, especially where it has potential
to cause damage. Usually a failure is not recovered by the electronic equipment without physical
or economic damage. Failures include shut-down and abnormal operation of the electronic
equipment. Incorrect calculations can also be categorized as failures. An error does not always
cause an electronic equipment hazard or failure, because it can disappear or be masked during
propagation in the device or board by some masking effects. Some mitigation techniques like
parity, ECC, and memory interleaving can be applied to reduce the likelihood of error
propagation.
Single-event effects occur as a result of a single particle penetrating a device; such a single
particle can nonetheless cause more than one error. For example, a single bit-flip is known as
a single-event upset (SEU); when a single particle causes multiple bit-flips, this is known as a
multiple-cell upset (MCU). Nonetheless, an MCU is still defined as an SEE, because it was
caused by a single particle. The fact that single particles cause the effects under consideration
is central to the statistical analysis of SEEs. An important aspect to note is that the soft error
rate (SER) in this case is defined by the number of SEUs, not by the number of errors. See
IEC 62396-1 for more details.
NOTE 1 Informative Annex A describes the structure of CMOS semiconductor devices
NOTE 2 Informative Annex B describes the interaction of particles with CMOS semiconductor devices.

Table 1 – General modes of faults
In-situ recovery/
Affected In-situ detection
Type Definition Phenomenon Name Characteristics Source mitigation
area method
method
Single transient due to charge collected by the diffusion layer Time and/or space
Single event in the chip. Pulse width is below a few nanoseconds, and can redundancy such as
transient last more than two clock pulses. It can result in different effects double/triple
Time and/or space
(SET) (SEU, SET, SEFI, SEB…) depending on the electronic device modular redundancy
redundancy
and the usage conditions. (DMR/TMR)
Single event Data flip in memory elements (SRAM DRAM, flip-flop, flash Error correction
Random but
upset (SEU) memory etc.) by a single particle hit. code (ECC)/parity
Well/
limited to a
substrate
Simultaneous SETs in more than two diffusion layers. Mainly,
single well
Multi-node MNTs take place in a single well due to charge sharing or Monitoring the well
Transient/
transient bipolar action. Space redundancy techniques such as dual potential and/or Reboot
noise
Transient in
(MNT) interlocked storage cell (DICE) or TMR might not work against current
electric potential
MNTs.
and/or current in
Multiple cell Rewrite/
a chip
Data flips in multiple memory elements by a single particle hit. ECC/parity
upset (MCU) reboot
Radiation
When a charged particle passes through a thin tunnel oxide, a
Very thin oxide
induced Random but
leakage path is formed in the tunnel oxide and the potential in
Single-event under high
leakage limited to ECC/parity ECC
the oxide can rise, resulting in a change in the effective V
effects electrical
th
current tunnel oxide
(SEEs) stress
and causing a soft error.
(RILC)
Single event
functional Loss of functionality in an electronic circuit. It can be recovered Random in Instruction exception Restoring
Well/substrate
interrupt by restoring flip-flop (FF) data to default values. a small area at CPU level FF data
-
(SEFI)
(Not
Two-
deterministic)
Monitoring the well
Single event Current continues to flow flipping multiple cell data. It can be (Parasitic) dimensional Power
potential and/or
latchup (SEL) recovered by power cycling (power off and on). PNP junctions multiple cycling
current
cells
Large destructive
current in a Single event Monitoring the well
Destructive bipolar effect in a semiconductor channel Random in Derating operating
channel or burnout PNP junctions potential and/or
particularly in a power device. a small area voltage
through oxide (SEB) current
Permanent
film
Oxide films
effects
Single event
under high Random in Derating operating
aate rupture Destructive effect on oxide films particularly in a power device. -
electrical a small area voltage
(SEGR)
stress
Damage or interstitials in a crystal, which can deteriorate
Anywhere/ Random in Annealing
Lattice defects Displacement damage (DD) device functionality. Can cause bits to stick at “0/1”and can be -
tunnel oxide a small area can work
permanent.
Cumulative
effects
Hole
Total ionizing dose (TID) Parasitic levels due to traps/impurities can cause functional Random in Annealing
V measurement
trap/impurity Oxide
th
effects deterioration or potential shift. a small area can work
migration
– 18 – IEC TR 62396-8:2020 © IEC 2020

Figure 6 – Typical hierarchy of fault conditions: Fault-error-failure
SEE rates can be quantified by means of a cross section, σ , defined by:
SEE
N
SEE
σ = (1)
SEE
Φ
p
where:
N is the number of SEU events;
SEE
−2
Φ is the fluence of particles (cm ).
p
NOTE 1 Fluence means the total number of particles passing through a unit area.
2 2 −1
NOTE 2 σ is expressed in cm , which can be per device or, for memory devices, per bit (cm ·b ).
SEE
The cross section can be measured thanks to accelerator experiments and one can calculate a
corresponding failure in time (FIT) rate as follows:
(2)
FIT σφ×××1 10
SEE p
where:
-1 -2
φ is the flux of particles (particles h cm ).
p
NOTE 3 Flux means the number of particles passing through a unit area per unit time.
NOTE 4 FIT (failure in time) means the number of failures that can be expected in 10 h of operation.
4.3 General sources of radiation
4.3.1 General sources of terrestrial radiation
Figure 7 depicts two simplified mechanisms by which ionizing radiation can be produced.
=
a) b)
Figure 7 – Sources of atmospheric ionizing radiation:
Nuclear reactions and radioactive decay
4.3.2 Atmospheric radiation particles
The particles listed in Table 2 participate in cosmic radiation showers and can cause
interactions with electronic components.
Table 2 – Properties of atmospheric radiation particles

article Symbol Mass Charge Spin Mean lifetime Main decay

a
/MeV /s
mode
Photon 𝛾𝛾 0 0 1 stable not applicable
−
𝑒𝑒
Electron 0,511 −1 ½ stable not applicable

(𝛽𝛽)
Positron
+
𝑒𝑒 0,511 1 ½ stable not applicable

(anti-electron)
−  − −
−6
𝜇𝜇 105,66 −1 ½ 𝜇𝜇 →𝑒𝑒 +𝜈𝜈 +𝜈𝜈�
2,2 × 10 𝜇𝜇 𝑒𝑒
Muon
+ +
+
−6
𝜇𝜇 →𝑒𝑒 +𝜈𝜈� +𝜈𝜈
𝜇𝜇 105,66 1 ½
2,2 × 10 𝜇𝜇 𝑒𝑒
+ +
+  −8
𝜋𝜋 →𝜇𝜇 +𝜈𝜈
𝜋𝜋 139,57 1 0 2,6 × 10
𝜇𝜇
− −
−  −8
𝜋𝜋 →𝜇𝜇 +𝜈𝜈
Pion 𝜋𝜋 139,57 −1 0 2,6 × 10
𝜇𝜇
0  0
−17
𝜋𝜋 139,57 0 0 𝜋𝜋 →2𝛾𝛾
8,4 × 10
+
Proton 𝑝𝑝 938,27 1 ½ stable not applicable
0  0 + −
Neutron 𝑛𝑛 939,57 0 ½ 𝑛𝑛 →𝑝𝑝 +𝑒𝑒 +𝜈𝜈�
8,8 × 10
𝑒𝑒
𝛼𝛼
Alpha 3 733 2 0 stable not applicable
a
𝜈𝜈: neutrino, 𝜈𝜈̅ anti-neutrino.

– 20 – IEC TR 62396-8:2020 © IEC 2020
Charged particles, such as alpha particles, cause ionization directly and can cause SEE as they
do so. In general, for a given particle energy, particles are more highly ionizing if they carry
more charge, and the heavier they are. Ionizing particles are most highly ionizing at low
energies, close to their Bragg peaks. A high-energy particle is relatively low ionizing, because
its high velocity leads to a minor influence on the atoms it passes, and it slows down only
gradually as it passes through material, for example aircraft components or the semiconductor
material of an electronic device. As it slows, however, its ionizing power increases such that,
eventually, it reaches a
...