1、Designation: F 1190 99 (Reapproved 2005)Standard Guide forNeutron Irradiation of Unbiased Electronic Components1This standard is issued under the fixed designation F 1190; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of
2、 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.1. Scope1.1 This guide strictly applies only to the exposure ofunbiased silicon (SI) or gallium arsenide (GaAs) semiconduc-tor c
3、omponents (integrated circuits, transistors, and diodes) toneutron radiation from a nuclear reactor source to determinethe permanent damage in the components. Validated 1-MeVdamage functions codified in National Standards are notcurrently available for other semiconductor materials.1.2 Elements of t
4、his guide with the deviations noted mayalso be applicable to the exposure of semiconductors com-prised of other materials except that validated 1-MeV damagefunctions codified in National standards are not currentlyavailable.1.3 Only the conditions of exposure are addressed in thisguide. The effects
5、of radiation on the test sample should bedetermined using appropriate electrical test methods.1.4 This guide addresses those issues and concerns pertain-ing to irradiations with reactor spectrum neutrons.1.5 System and subsystem exposures and test methods arenot included in this guide.1.6 This guide
6、 is applicable to irradiations conducted withthe reactor operating in either the pulsed or steady-state mode.The range of interest for neutron fluence in displacementdamage semiconductor testing range from approximately 109to 1016n/cm2.1.7 This guide does not address neutron-induced single ormultipl
7、e neutron event effects or transient annealing.1.8 This guide provides an alternative to Test Method1017.3, Neutron Displacement Testing, a component of MIL-STD-883 and MIL-STD-750. The Department of Defense hasrestricted use of these MIL-STDs to programs existing in 1995and earlier.1.9 This standar
8、d 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 determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM
9、 Standards:2E 170 Terminology Relating to Radiation Measurementsand DosimetryE 264 Test Method for Determining Fast-Neutron ReactionRates by Radioactivation of NickelE 265 Test Method for Measuring Reaction Rates andFast-Neutron Fluences by Radioactivation of Sulfur32E 668 Practice for Application o
10、f Thermoluminescence Do-simetry (TLD) Systems for Determining Absorbed Dose inRadiation-Hardness Testing of Electronic DevicesE 720 Guide for Selection and Use of Neutron-ActivationFoils for Determining Neutron Spectra Employed inRadiation-Hardness Testing of ElectronicsE 721 Method for Determining
11、Neutron Energy Spectrawith Neutron-Activation Foils for Radiation-HardnessTesting of ElectronicsE 722 Practice for Characterizing Neutron Energy FluenceSpectra in Terms of an Equivalent Monoenergetic NeutronFluence for Radiation-Hardness Testing of ElectronicsE 1249 Practice for Minimizing Dosimetry
12、 Errors in Radia-tion Hardness Testing of Silicon Electronic Devices UsingCo-60 SourcesE 1250 Test Method for Application of Ionization Cham-bers to Assess the Low Energy Gamma Component ofCobalt-60 Irradiators Used in Radiation-Hardness Testingof Silicon Electronic DevicesE 1854 Practice for Ensuri
13、ng Test Consistency in Neutron-Induced Displacement Damage of Electronic PartsF 980 Guide for the Measurement of Rapid Annealing ofNeutron-Induced Displacement Damage in SemiconductorDevices.F 1892 Guide for Ionizing Radiation (Total Dose) EffectsTesting of Semiconductor Devices2.2 Other Documents:2
14、.2.1 The Department of Defense publishes every fewyears a compendium of nuclear reactor facilities that may besuitable for neutron irradiation of electronic components:1This guide is under the jurisdiction of ASTM Committee F01 on Electronicsand is the direct responsibility of Subcommittee F01.11 on
15、 Quality and HardnessAssurance.Current edition approved Jan. 1, 2005. Published January 2005. Originallyapproved in 1988. Last previous edition approved in 1999 as F 1190 99.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For
16、Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.DASIAC SR-94-009, April 1996, Guide to Nuclear Weap-ons Effects Simulati
17、on Facilities and Techniques32.3 The Office of the Federal Register, National Archivesand Records Administration publishes several documents thatdelineate the regulatory requirements for handling and trans-porting radioactive semiconductor components:Code of Federal Regulations: Title 10 (Energy), P
18、art 20,Standards for Protection Against Radiation4Code of Federal Regulations: Title 10 (Energy), Part 30,Rules of General Applicability to Domestic Licensing ofByproduct Material4Code of Federal Regulations: Title 49 (Transportation),Parts 100 to 17743. Terminology3.1 1 MeV equivalent fluencethis e
19、xpression is used bythe radiation-hardness testing community to refer to the char-acterization of an incident neutron energy fluence spectrum,F(E), in terms of the fluence of monoenergetic neutrons at 1MeV energy required to produce the same displacementdamage in a specified irradiated material as F
20、(E) (see PracticeE 722 for details).3.1.1 DiscussionHistorically, the material has been as-sumed to be silicon (Si). The emergence of gallium arsenide(GaAs) as a significant alternate semiconductor material,whose radiation damage effects mechanisms differ substan-tially from Si based devices, requir
21、es that future use of the 1MeV equivalent fluence expression include the explicit speci-fication of the irradiation semiconductor material.3.2 silicon damage equivalent (SDE)expression synony-mous with “1 MeV equivalent fluence in silicon.”3.3 equivalent monoenergetic neutron fluence(Feq,Eref, mat.)
22、an equivalent monoenergetic neutron fluencethat characterizes an incident energy-fluence spectrum, F(E),in terms of the fluence of monoenergetic neutrons at a specificenergy, Eref, required to produce the same displacementdamage in a specified irradiated material, mat (see PracticeE 722 for details)
23、.3.3.1 DiscussionThe appropriate expressions for com-monly used 1 MeV equivalent fluence are Feq, 1 MeV, Siforsilicon semiconductor devices and Feq, 1 MeV, GaAsfor galliumarsenide based devices. See Practice E 722 for a more thoroughtreatment of the meaning and significant limitations imposedon the
24、use of these expressions.4. Summary of Guide4.1 Evaluation of neutron radiation-induced damage insemiconductor components and circuits requires that the fol-lowing steps be taken:4.1.1 Select a suitable reactor facility where the radiationenvironment and exposure geometry desired are both availablea
25、nd currently characterized (within the last 15 months). Areasonably complete list is contained in DASIAC SR-94-009.Practice E 1854 contains detailed guidance to assist the user inselecting a reactor facility that is certified to be adequatelycalibrated.4.1.2 Prepare test plan and fixtures,4.1.3 Cond
26、uct pre-irradiation electrical test of the testsample,4.1.4 Expose test sample and dosimeters,4.1.5 Retrieve irradiated test sample,4.1.6 Read dosimeters,4.1.7 Conduct post-irradiation electrical tests, and4.1.8 Repeat 4.1.4 through 4.1.7 until the desired cumula-tive fluence is achieved or until de
27、gradation of the test devicewill not allow any further useful data to be taken.4.2 Operations addressed in this guide are only thoserelating to reactor facility selection, irradiation procedure andfixture development, positioning and exposure of the testsample, and shipment of the irradiated samples
28、 to the parentfacility. Dosimetry methods are covered in existing ASTMstandards referenced in Section 2, and many pre- and post-exposure electrical measurement procedures are contained inthe literature. Dosimetry is usually supplied by the reactorfacility.5. Significance and Use5.1 Semiconductor dev
29、ices are permanently damaged byreactor spectrum neutrons. The effect of such damage on theperformance of an electronic component can be determined bymeasuring the component electrical characteristics before andafter exposure to fast neutrons in the neutron fluence range ofinterest. The resulting dat
30、a can be utilized in the design ofelectronic circuits that are tolerant of the degradation exhibitedby that component.5.2 This guide provides a method by which the exposure ofsilicon and gallium arsenide semiconductor devices to neutronirradiation may be performed in a manner that is repeatable andw
31、hich will allow comparison to be made of data taken atdifferent facilities.5.3 For semiconductors other than silicon and galliumarsenide, this guide provides a method that can improveconsistency in the measurements and assurance that data fromvarious facilities can be compared on the same equivalenc
32、efluence scale when the applicable validated 1-MeV damagefunctions are codified in National standards. In the absence ofa validated 1-MeV damage function, the non-ionizing energyloss (NIEL) as a function incident neutron energy, normalizedto the NIEL at 1 MeV, may be used as an approximation. SeePra
33、ctice E 722 for a description of the method.6. Interferences6.1 Gamma Effects:6.1.1 All nuclear reactors produce gamma radiation coinci-dent with the production of neutrons. Gamma rays are pro-duced in the fission process directly and are emitted by fissionproducts and activated materials. Furthermo
34、re, these gammarays produce secondary gamma rays and fluorescence photonsin reactor fuel, moderator, and surrounding materials. Conse-quently, degradation in piecepart performance may be pro-duced by gamma rays as well as neutrons, and because of thesofter photon spectra dose enhancement may be a pr
35、oblem. If3Available from Defense Special Weapons Agency, Washington, DC 20305-1000.4Available from the Superintendent of Documents, U.S. Government PrintingOffice, Washington, DC 20402.F 1190 99 (2005)2a separation of neutron (n) and gamma ray (g) degradation isdesired, either the n/g ratio must be
36、increased to the point atwhich gamma effects are negligible or the test sample degra-dation must first be characterized in a “pure” gamma rayenvironment under zero bias conditions. The use of such datafrom a gamma ray exposure to separate neutron and gammaeffects obtained during a neutron exposure m
37、ay be a complextask. If this approach is taken, Guide F 1892 should be used asa reference. Guides E 1249 and E 1250 should be used toaddress dose enhancement issues.6.1.2 TRIGA-type reactors (Training Research and Isotopeproduction reactor manufactured by General Atomics) delivergamma dose during ne
38、utron irradiations that can vary consid-erably depending on the immediately preceding operatinghistory of the reactor. A TRIGA-type reactor that has beenoperating at a high power level for an extended period prior tothe semiconductor component neutron irradiation will containa larger fission product
39、 inventory that will contribute signifi-cantly higher gamma dose than a reactor that has had no recenthigh level operations. The experimenter must determine themaximum gamma dose his experiment can tolerate, and advisethe facility operator to provide sufficient shielding to meet thislimit.6.2 Temper
40、ature EffectsAnnealing of neutron damage isenhanced at elevated temperatures. Elevated temperatures mayoccur during irradiation, transportation, storage, or electricalcharacterization of the test devices.6.3 Dosimetry Errors Neutron fluence is typically re-ported in terms of an equivalent 1 MeV mono
41、energetic neutronfluence in the specified irradiated material (Feq, 1 MeV, SiorFeq, 1 MeV, GaAs) in units of neutrons per square centimeter.ASTM guidelines and standards exist for calculating this valuefrom measured reactor characteristics. However, reactor facili-ties may not routinely remeasure th
42、e neutron spectrum, (usingGuide E 720 and Method E 721) at the test sample exposuresites. A currently valid determination of the neutron spectrumis needed to provide the essential data to accurately ascertainthe equivalent 1 MeV monoenergetic neutron fluence in thespecified irradiated material. Lack
43、 of this critical data canresult in substantial error. Therefore the experimenter mustobtain a current valid determination of the 1 MeV equivalentfluence in silicon or GaAs, as needed, from the reactor facilityoperator. This may require a recharacterization of the reactortest facility, or the partic
44、ular test configuration.6.4 Recoil Ionization EffectsIonization effects from neu-tron recoils within a semiconductor device may be significantfor some device types at very high neutron fluences, althoughunder normal conditions, ionization due to the gamma radia-tion from the source will be much grea
45、ter than the ionizationfrom recoils.6.5 Test Configuration EffectsExtraneous materials in thevicinity of the test specimens can modify the environment atthe test sample location. Both the neutron spectrum and thegamma field can be altered by the presence of such materialeven if these materials are n
46、ot interposed between the reactorcore and the test devices.6.6 Thermal Neutron EffectsFast Burst Reactor (FBR)neutron spectra have a small thermal neutron component;however, TRIGA reactors inherently produce a very largethermal neutron flux. Neutrons interact with the materials ofthe devices being i
47、rradiated causing them to become radioac-tive. Thermal neutrons generally induce higher levels ofradioactivity. As a consequence, parts irradiated at TRIGAreactors to moderate or high levels should not be handled ormeasured soon after exposure. It is therefore common practiceat TRIGA reactors to shi
48、eld test parts from the thermalneutrons with borated polyethylene or cadmium shields. Cad-mium capture of thermal neutrons produces more gamma raysthan boron capture, thus producing a lower n/g ratio when sucha shield is used. For this reason, borated polyethylene shieldsare preferred. While most fa
49、cilities providing neutron irradia-tion for semiconductor parts will automatically provide thethermal neutron shields, it is the experimenters responsibilityto verify that such a shield is employed during the irradiation.7. Procedure7.1 Reactor Facility Selection:7.1.1 Reactor Operating Modes and Fluence LevelsTwotypes of reactors are generally used for evaluating the displace-ment effects of neutrons on electronic components. Thesereactors, the FBR and the TRIGA types, can be operated ineither a pulsed or a steady-state mode. The minimum pulsewidth for the FBR is approx
