1、Designation: F744M 16Standard Test Method forMeasuring Dose Rate Threshold for Upset of DigitalIntegrated Circuits (Metric)1This standard is issued under the fixed designation F744M; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision,
2、the year of last revision. A number in parentheses indicates the year of last reapproval. Asuperscript epsilon () indicates an editorial change since the last revision or reapproval.This standard has been approved for use by agencies of the U.S. Department of Defense.1. Scope1.1 This test method cov
3、ers the measurement of the thresh-old level of radiation dose rate that causes upset in digitalintegrated circuits only under static operating conditions. Theradiation source is either a flash X-ray machine (FXR) or anelectron linear accelerator (LINAC).1.2 The precision of the measurement depends o
4、n thehomogeneity of the radiation field and on the precision of theradiation dosimetry and the recording instrumentation.1.3 The test may be destructive either for further tests or forpurposes other than this test if the integrated circuit beingtested absorbs a total radiation dose exceeding some pr
5、edeter-mined level. Because this level depends both on the kind ofintegrated circuit and on the application, a specific value mustbe agreed upon by the parties to the test (6.8).1.4 Setup, calibration, and test circuit evaluation proceduresare included in this test method.1.5 Procedures for lot qual
6、ification and sampling are notincluded in this test method.1.6 Because of the variability of the response of differentdevice types, the initial dose rate and device upset conditionsfor any specific test is not given in this test method but must beagreed upon by the parties to the test.1.7 The values
7、 stated in SI units are to be regarded asstandard. No other units of measurement are included in thisstandard.1.8 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 safet
8、y and health practices and determine the applica-bility of regulatory limitations prior to use.2. Referenced Documents2.1 ASTM Standards:2E666 Practice for Calculating Absorbed Dose From Gammaor X RadiationE668 Practice for Application of Thermoluminescence-Dosimetry (TLD) Systems for Determining Ab
9、sorbedDose in Radiation-Hardness Testing of Electronic DevicesE1894 Guide for Selecting Dosimetry Systems for Applica-tion in Pulsed X-Ray SourcesF526 Test Method for Using Calorimeters for Total DoseMeasurements in Pulsed Linear Accelerator or FlashX-ray Machines3. Terminology3.1 Definitions:3.1.1
10、combinatorial logic circuitintegrated circuit whoseoutput is a unique function of the inputs; the output changes ifand only if the input changes (for example, AND- andOR-gates).3.1.2 dose rateenergy absorbed per unit time and per unitmass by a given material from the radiation to which it isexposed.
11、3.1.3 dose rate threshold for upsetminimum dose rate thatcauses either: (1) the instantaneous output voltage of anoperating digital integrated circuit to be greater than thespecified maximum LOW value (for a LOW output level) orless than the specified minimum HIGH value (for a HIGHoutput level), or
12、(2) a change of state of any stored data.3.1.4 sequential logic circuitintegrated circuit whose out-put or internal operating conditions are not unique functions ofthe inputs (for example, flip-flops, shift registers, and RAMs).4. Summary of Test Method4.1 The test device and suitable dosimeters are
13、 irradiated byeither an FXR or a linac. The test device is operating but under1This test method is under the jurisdiction of ASTM Committee F01 onElectronics and is the direct responsibility of Subcommittee F01.11 on Nuclear andSpace Radiation Effects.Current edition approved May 1, 2016. Published
14、May 2016. Originallyapproved in 1981. Last previous edition approved in 2010 as F744M 10. DOI:10.1520/F0744M-16.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Service at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the
15、standards Document Summary page onthe ASTM website.Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States1static conditions. The output(s) of the test device and of thedosimeters are recorded.4.2 The dose rate is varied to determine the rate
16、 whichresults in upset of the test device.4.3 For the purposes of this test method, upset is consideredto be either of the following:4.3.1 An output voltage transient exceeding a predeter-mined value, or4.3.2 For devices having output logic levels which are notunique functions of the input logic lev
17、els, such as flip-flops, achange in the logic state of an output.4.3.3 For sequential logic circuits, a change of state of aninternal storage element or node.4.4 A number of factors are not defined in this test method,and must be agreed upon beforehand by the parties to the test:4.4.1 Total ionizing
18、 dose limit (see 1.3),4.4.2 Transient values defining an upset (see 4.3.1),4.4.3 Temperature at which the test is to be performed (see6.7),4.4.4 Details of the test circuit, including output loading,power supply levels, type of package, and other operatingconditions (see 7.4, 10.3, and 10.4),4.4.5 C
19、hoice of radiation pulse source (see 7.7),4.4.6 Radiation pulse width and rise time (see 7.7.2),4.4.7 Sampling (see 8.1),4.4.8 Need for total ionizing dose measurement (see 6.8,7.6, and 10.1),4.4.9 Desired precision of the upset threshold (see 10.8),and4.4.10 Initial dose rate (see 1.6 and 10.5).5.
20、Significance and Use5.1 Digital integrated circuits are specified to operate withtheir inputs and outputs in either a logical 1 or a logical 0 state.The occurrence of signals having voltage levels not meetingthe specifications of either of these levels (an upset condition)may cause the generation an
21、d propagation of erroneous data ina digital system.5.2 Knowledge of the radiation dose rate that causes upsetin digital integrated circuits is essential for the design,production, and maintenance of electronic systems that arerequired to operate in the presence of pulsed radiation envi-ronments.6. I
22、nterferences6.1 Air IonizationA spurious component of the signalmeasured during a test can result from conduction through airionized by the radiation pulse. The source of such spuriouscontributions can be checked by measuring the signal whileirradiating the test fixture in the absence of a test devi
23、ce. Airionization contributions to the observed signal are generallyproportional to the applied field, while those due to secondaryemission effects (6.2) are not. The effects of air ionizationexternal to the device may be minimized by coating exposedleads with a thick layer of paraffin, silicone rub
24、ber, or noncon-ductive enamel or by making the measurement in a vacuum.6.2 Secondary EmissionAnother spurious component ofthe measured signal can result from charge emission from, orcharge injection into, the test device and test circuit.3This maybe minimized by shielding the surrounding circuitry a
25、ndirradiating only the minimum area necessary to ensure irradia-tion of the test device. Reasonable estimates of the magnitudeto be expected of current resulting from secondary-emissioneffects can be made based on the area of metallic targetmaterials irradiated (see Note 1). Values generally rangebe
26、tween 1011and 1010As/cm2Gy, but the use of a scatterplate for electrons with an intense beam may increase thiscurrent (7.7.2).NOTE 1For dose rates in excess of 108-Gy(Si)/s, the photocurrentsdeveloped by the package may dominate the device photocurrent. Careshould be taken in the interpretation of t
27、he measured photoresponse forthese high dose rates.6.3 OrientationThe effective dose to a semiconductorjunction can be altered by changing the orientation of the testdevice with respect to the irradiating beam. Most integratedcircuits may be considered “thin samples” (in terms of therange of the rad
28、iation). However, some devices may havecooling studs or thick-walled cases that can act to scatter theincident beam, thereby modifying the dose received by thesemiconductor chip. Care must be taken in the positioning ofsuch devices.6.4 Dose EnhancementHigh atomic number materialsnear the active regi
29、ons of the integrated circuit (package,metallization, die attach materials, etc.) can cause an enhanceddose to be delivered to the sensitive regions of the device whenit is irradiated with bremsstrahlung. Therefore, when an FXR isused as the radiation source, calculations should be performedto deter
30、mine the possibility and extent of this effect.6.5 Electrical NoiseSince radiation test facilities are in-herent sources of rf electrical noise, good noise-minimizingtechniques such as single-point ground, filtered dc supply lines,etc., must be used in these measurements.6.6 TemperatureDevice charac
31、teristics are dependent onjunction temperature; hence, the temperature of the test shouldbe controlled. Unless the parties to the test agree otherwise,measurements shall be made at room temperature (24 6 6C).6.7 Beam Homogeneity and Pulse-to-Pulse RepeatabilityThe intensity of a beam from an FXR or
32、a LINAC is likely tovary across its cross section. Since the pulse-shape monitor isplaced at a different location than the device under test, themeasured dose rate may be different from the dose rate towhich the device was exposed. The spatial distribution andintensity of the beam may also vary from
33、 pulse to pulse. Thebeam homogeneity and pulse-to-pulse repeatability associatedwith a particular radiation source should be established by athorough characterization of its beam prior to performing ameasurement.6.8 Total Ionizing DoseEach pulse of the radiation sourceimparts an ionizing dose to bot
34、h the device under test and the3Sawyer, J. A., and van Lint, V. A. J., “Calculations of High-Energy SecondaryElectron Emission,” Journal of Applied Physics, Vol 35, No. 6, June 1964, pp.17061711.F744M 162device used for dosimetry. The total ionizing dose deposited ina semiconductor device can change
35、 its operating characteris-tics. As a result, the response that is measured after severalpulses may be different from that characteristic of an unirra-diated device. Care should be exercised to ensure that the totalionizing dose delivered to the test device is less than theagreed-upon maximum value.
36、 Care must also be taken toensure that the characteristics of the dosimeter have notchanged due to the accumulated dose.7. Apparatus7.1 Regulated dc Power SupplyA power supply to pro-duce the voltages required to bias the integrated circuit undertest.7.2 Recording Devicessuch as digital storageoscil
37、loscopes, or other suitable instruments. The bandwidthcapabilities of the recording devices shall be such that theradiation responses of the integrated circuit and the pulse-shapemonitor (7.6) are accurately displayed and recorded.7.3 CablingTo adequately complete the connection of thetest circuit i
38、n the exposure area with the power supply andoscilloscopes in the data area. Shielded twisted pair or coaxialcables may be used to connect the power supplies to the biaspoints of the test circuit; however, coaxial cables properlyterminated at the oscilloscope input are required for the signalleads.7
39、.4 Test Circuit (see Fig. 1)Although the details of testcircuits for this test must vary depending on the kind ofintegrated circuit to be tested and on the specific parameters ofthe circuit which are to be measured, Fig. 1 provides theinformation necessary for the design of a test circuit for mostpu
40、rposes.The capacitor, C, provides an instantaneous source ofcurrent as may be required by the integrated circuit during theradiation pulse. Its value must be large enough that thedecrease in the supply voltage during a pulse is less than 10 %.The capacitor, C, should be paralleled by a small (approx
41、i-mately 0.01 F) low-inductance capacitor to ensure thatpossible inductive effects of the large capacitor are offset. Bothcapacitors must be located as close to the integrated circuitsocket as possible, consistent with the space needed forconnection of the current transformer and for any shielding t
42、hatmay be necessary. The switch, S, provides means to place theoutput of the integrated circuit (here a NAND gate) in either alogic LOW or a logic HIGH state. The arrangement of thegrounding connections provides that only one ground exists, atthe point of measurement. This eliminates the possibility
43、 ofground loops and reduces the common-mode signals present atthe terminals of the measurement instruments. The resistor, R0,is the termination for the coaxial cable and has a value within2 % of the characteristic cable impedance.All unused inputs tothe test device are connected as agreed upon betwe
44、en theparties to the test. The output of the test device may be loaded,as agreed upon between the parties to the test. To preventloading of the output of the test device by the coaxial cable,one may use a line driver that has a high input impedance andadequate bandwidth and voltage swing to reproduc
45、e accuratelyat the output end of the coaxial cable, the waveforms appearingat the line-driver input.7.5 Radiation Pulse-Shape MonitorUse one of the follow-ing to develop a signal proportional to the dose rate deliveredto the test device. (The carrier lifetime in any of these devicesshould be less th
46、an5%ofthepulse width of the radiation.)7.5.1 Fast Signal Diodein the circuit configuration of Fig.2. The resistors, R1, serve as high-frequency isolation and mustbe at least 20. The capacitor, C, supplies the charge duringthe current transient; its value must be large enough that thedecrease in volt
47、age during a current pulse is less than 10 %.FIG. 1 Example of a Test Circuit for a NAND GateF744M 163The capacitor, C, should be paralleled by a small (approxi-mately 0.01 F) low-inductance capacitor to ensure thatpossible inductive effects of the large capacitor are offset. Theresistor, R0, is to
48、provide the proper termination (within 62%)for the coaxial cable used for the signal lead. This is thepreferred apparatus for this purpose. The signal measured at R0should be less than 10 % of the applied voltage to prevent thedebiasing of the detector that will affect the measured response.7.5.2 P-
49、I-N Diodein the circuit configuration of Fig. 2 asdescribed in 7.5.1. Care should be taken to avoid saturationeffects.7.5.3 PCDa photoconductive detector. Diamond or GaAsare typical PCD active materials. This active dosimeter has avery rapid, picosecond response to the ionizing dose in theactive material.7.5.4 Current Transformer mounted on a collimator at theoutput window of the linear accelerator so that the primaryelectron beam passes through the opening of the transformerafter passing through the collimator. The current transformermust have a ban
