1、Designation: F 1192 00 (Reapproved 2006)Standard Guide for theMeasurement of Single Event Phenomena (SEP) Induced byHeavy Ion Irradiation of Semiconductor Devices1This standard is issued under the fixed designation F 1192; the number immediately following the designation indicates the year oforigina
2、l adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon (e) indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the Department of Defe
3、nse.1. Scope1.1 This guide defines the requirements and procedures fortesting integrated circuits and other devices for the effects ofsingle event phenomena (SEP) induced by irradiation withheavy ions having an atomic number Z $ 2. This descriptionspecifically excludes the effects of neutrons, proto
4、ns, and otherlighter particles that may induce SEP via another mechanism.SEP includes any manifestation of upset induced by a singleion strike, including soft errors (one or more simultaneousreversible bit flips), hard errors (irreversible bit flips), latchup(permanent high conducting state), transi
5、ents induced in com-binatorial devices which may introduce a soft error in nearbycircuits, power field effect transistor (FET) burn-out and gaterupture. This test may be considered to be destructive becauseit often involves the removal of device lids prior to irradiation.Bit flips are usually associ
6、ated with digital devices and latchupis usually confined to bulk complementary metal oxide semi-conductor, (CMOS) devices, but heavy ion induced SEP is alsoobserved in combinatorial logic programmable read onlymemory, (PROMs), and certain linear devices that may re-spond to a heavy ion induced charg
7、e transient. Power transitorsmay be tested by the procedure called out in Method 1080 ofMIL STD 750.1.2 The procedures described here can be used to simulateand predict SEP arising from the natural space environment,including galactic cosmic rays, planetary trapped ions and solarflares. The techniqu
8、es do not, however, simulate heavy ionbeam effects proposed for military programs. The end productof the test is a plot of the SEP cross section (the number ofupsets per unit fluence) as a function of ion LET (linear energytransfer, or ionization deposited along the ions path throughthe semiconducto
9、r). This data can be combined with thesystems heavy ion environment to estimate a system upsetrate.1.3 Although protons can cause SEP, they are not includedin this guide. A separate guide addressing proton induced SEPis being considered.1.4 The values stated in International System of Units (SI)are
10、to be regarded as standard. No other units of measurementare included in this guide.1.5 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is theresponsibility of the user of this standard to establish appro-priate safety and health practices and
11、 determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 Military Standard:2750 Method 10803. Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 DUTdevice under test.3.1.2 fluencethe flux integrated over time, expressed asions/cm2.3.1.3 fluxthe
12、 number of ions/s passing through a one cm2area perpendicular to the beam (ions/cm2-s).3.1.4 LETthe linear energy transfer, also known as thestopping power dE/dx, is the amount of energy deposited perunit length along the path of the incident ion, typicallyexpressed as MeV-cm2/mg.3.1.4.1 DiscussionL
13、ET values are obtained by dividingthe energy per unit track length by the density of the irradiatedmedium. Since the energy lost along the track generateselectron-hole pairs, one can also express LET as chargedeposited per unit path length (for example, picocoulombs/micron) if it is known how much e
14、nergy is required to generatean electron-hole pair in the irradiated material. (For silicon,3.62 eV is required per electron-hole pair.)A correction, important for lower energy ions in particular, is madeto allow for the loss of ion energy after it has penetrated overlayers1This guide is under the j
15、urisdiction of ASTM Committee F01 on Electronicsand is the direct responsibility of Subcommittee F01.11 on Nuclear however, in general, DUTs may be safely packed and trans-ported without delay after test.6.7 Ion Interaction Effects:6.7.1 The calculation of an effective LET (see discussion in3.1.4) h
16、inges on the thin slab approximation of the sensitivevolume, which is less likely to hold for high density, smallgeometry devices. This problem can be examined by investi-gating the device SEP response to two different ions having thesame effective LET.6.7.2 The proportion of length to width of the
17、sensitivevolume is also assumed equal to one. Rotating the device alongboth axes of symmetry during the test may provide a moremeaningful characterization.6.7.3 As geometries continue to scale down, the possibilityof multiple bit upsets increases. Hence, the nature of the ionsradial energy depositio
18、n becomes more important and itbecomes more likely that two different ions of equivalent LETdo not in fact have an equal SEP effect. In addition, the effectsof irradiating at an angle become much more complex when anion track overlaps two cells. The frequency of such overlap-ping upsets likewise dep
19、ends on the tracks radial energydeposition.6.7.4 Another assumption is that the ions energy depositionis in equilibrium at the device sensitive volume after the ionstrikes the device. This may not always be the case with a topsurface irradiation. One can investigate this possibility byirradiating th
20、e back of the device with highly energetic ions ofadequate range. In the latter case, it is known that the ionsenergy deposition will be in equilibrium when the ion reachesthe sensitive volumes located near the surface.6.7.5 Use of ions having adequate range is also important.Lower energy heavy ions
21、 lose LET as they slow down byattaching electrons and also show a contraction in the width ofthe radial energy deposition.7. Apparatus and Radiation Sources7.1 Particle Radiation SourcesThe choice of radiationsources is important. Hence source selection guidelines aregiven here. A test covering the
22、full range of LET values (bothhigh and low Z ions) will require an accelerator. Cost,availability, lead times, and ion/energy capabilities are allimportant considerations in selecting a facility for a given test.Three source types are commonly used for conducting SEPexperiments, each of which has sp
23、ecific advantages and disad-vantages. The selection of a proper source that meets the testobjectives in a cost-effective manner depends on test objectivesand device appraisal (see 8.1.).7.1.1 The three source types used for heavy ion SEPmeasurement are as follows:7.1.1.1 CyclotronsCyclotrons provide
24、 the greatest flex-ibility of test options because they can supply a number ofdifferent ions (including alpha particles) at a finite number ofdifferent energies. The maximum available ion energy of theheavy ion machines is usually greater than the energy (;2MeV/nucleon) corresponding to the maximum
25、LET. Hence, theions can be selected to have adequate penetration (range) in thedevice.7.1.1.2 Van de Graaff AcceleratorsThese acceleratorshave the important advantage of being able to pinpoint lowLET thresholds of sensitive devices where lower energy, lowerZ ions of continuously variable energies ar
26、e desirable. Thesemachines also offer a rapid change of ion species and aresomewhat less expensive to operate than cyclotrons. However,because van de Graaff machines have limited energy, it maynot be possible to obtain higher Z particles having an adequaterange in some machines.7.1.1.3 Alpha Emitter
27、s Naturally occurring radioactivealpha emitters provide a limited source for screening parts thatare very sensitive to SEU. Some alpha emitters (for example,americium) emit particles with a single energy so that they canbe used for establishing a precise LET threshold (of the orderof 1 MeV/(mg/cm2).
28、7.2 Test InstrumentationThe test instrumentation can bedivided into two categories: (1) Beam delivery, characteriza-tion and dosimetry, and (2) Device tester (input stimulusgenerator and response recorder) designed to accommodate thespecified devices. The details of item (1) above are spelled outF 1
29、192 00 (2006)4in 7.5.4, 7.5.5 and 7.5.6. The details of item (2) cannot bespelled out, but test philosophy and logic is sketched in 7.4. Forinformation on various test instrumentation systems refer toNichols.37.3 Test Boards The DUTs will be placed on a board,usually within a vacuum chamber, during
30、the test. To reducethe number of vacuum pump downs that will be required, it ishighly desirable to include sockets in the boards for severaldevices. The board must be remotely positionable to changefrom one DUT under test to another, and rotatable to permit thebeam to strike the DUT at oblique angle
31、s. Tester-to-DUT cardcabling should be made compatible with the vacuum chamberbulkhead connectors to facilitate checkout prior to chamberinstallation.7.4 DUT Tester:7.4.1 There are many ways to design a tester/counter tomeasure soft errors, with special features best suited to aspecified test applic
32、ation. However, there are certain generaldesirable features which any tester design should incorporate,and these will be addressed briefly.7.4.2 Except in the simplest of special cases where adedicated hardware tester is most desirable, the tests areperformed by a computer, which exercises the DUTs
33、directly,or alternatively makes use of an auxilliary “exerciser” orpattern operator. A tester whose design is based on the firstapproach, can be said to be “Computer Dominated,” while thesecond type of design has been termed “Computer Assisted.”Regardless of the test approach, the tester must be abl
34、e to carryout the following operations:7.4.2.1 Device initialization and functionality check,7.4.2.2 Device operation while under irradiation,7.4.2.3 Error detection and logging,7.4.2.4 Diagnostic display in real or near-real time, and7.4.2.5 Data processing, storage and retrieval for display.7.4.3
35、While an effectively infinite variety of testers can bebuilt to function adequately in any given set of circumstances,every tester, in addition to performing the operations listedabove, should possess most of the following characteristics:7.4.3.1 Adaptability to many device types. This generallyimpl
36、ies software control with programs written in a high-levellanguage,7.4.3.2 Well-defined duty factor (ratio of device “live” timeto total elapsed time). Without a knowledge of the duty factor,device vulnerability cannot be quantified,7.4.3.3 Speed of operation and high duty factor. This isespecially
37、important when tests are performed in a high particleflux. Generally, a computer-assisted tester design is implied bythis characteristic,7.4.3.4 Real-time diagnostic data display capability. Man-datory for immediate detection of anomalous test conditionsand data, and7.4.3.5 Capability for some data
38、reduction while tests are inprogress. Desirable for optimization of test procedures whiledata are being acquired.7.4.4 In summary, a tester will usually be of the computer-dominated or computer-assisted type. It should be program-mable to accommodate a variety of device types with aminimum need for
39、new, specialized hardware interfaces andminimum time required for reprogramming. The tester designshould be sufficiently flexible to meet the changing require-ments of new device technologies. Finally, the experimentermust understand the extent to which the device is being tested(its fault coverage)
40、 in order to arrive at a quantitative result. Hemust know what fraction of the time the device is in aSEP-susceptible mode and also what fraction of the chipssusceptible elements are omitted from testing altogether. Com-plex devices do not always permit easy testing access. In suchcases, a thorough
41、understanding of the untested elements mustbe obtained to permit extrapolation from data obtained by thetest.7.5 A Typical Cyclotron Test Set-Up:7.5.1 SchematicA schematic overview of a typical SEPtest set-up is provided in Fig. 1. The essential features are acollimated, spatially uniform beam of pa
42、rticles entering avacuum chamber which may be located in an area remote (forexample, behind shielded walls) from the tester/counter anddosimetry electronics. Test boards, shutters, and beam diagnos-tic detectors are in, or near, the vacuum chamber.7.5.2 Vacuum Chamber A typical vacuum chamber inte-r
43、ior is shown in Fig. 2. The essential features are the beamcollimators/shutters and sensors, and a rotatable and translat-able board for positioning the selected DUT at the selectedangle in the beam. Dosimetry may or may not be located in thevacuum chamber.7.5.3 DUT BoardA typical board showing sock
44、ets forseveral DUTs is shown in Fig. 3, together with the associateddriver logic. A device located outside the beam can be used asa reference device or sometimes one-half of a test device canbe used to compare with the other half when the likelihood ofboth sides being hit at the same time is low. Th
45、e round holepermits passage of the beam to the downstream silicon surfacebarrier (SSB) detectors located at the rear of the chamberinterior. The horizontal hole in the test frame is an opening toa SSB detector that may be used to check beam uniformityalong the vertical axis.7.5.4 Beam Dosimetry Syst
46、em:7.5.4.1 The flux and fluence of the selected heavy ion beammay be measured by passing it through a scintillator. The beammay pass through a very thin (microns) foil whose thickness ischosen to give the proper light amplitude to correspond withthe beams LET. An alternate method is to insert an ann
47、ularscintillator into the beam which admits part of the beamunimpeded onto the DUT while the outer portion is stopped bya thick scintillator. The light is then piped to a photomultipliertube (PMT) and counted as shown in Fig. 4. The source facilitytypically provides the dosimetry.7.5.4.2 The bias ap
48、plied to the PMT will be increasedgradually until pulses are of adequate amplitude to permitdiscriminator adjustment. The discriminator must reject all3Nichols, D. K., et al, “Trends in Parts Susceptibility to Single Event UpsetFrom Heavy Ions,” IEEE Transactions on Nuclear Science, Vol NS-32, No. 6
49、,December, 1985, p. 4187. (See updated addition by D. K. Nichols et al in IEEETransactions on Nuclear Science, Vol NS-34, No. 6, December, 1987, p. 1332, VolNS-36, December, 1989, p. 2388, Vol NS-38, December, 1991, p. 1529, Vol NS-40,December 1993, Vol NS-42, December 1995, IEEE Radiation Effects DataWorkshop, December, 1993, p. 1). Sections on Single Event Phenomena, IEEETransactions on Nuclear Science, all December issues dating from 1979.F 1192 00 (2006)5noise pulses and pass all pulses caused by the beam particles.The beam intensity (flux) should be kept low e
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