ASTM F448-11
(Test Method)Test Method for Measuring Steady-State Primary Photocurrent
Test Method for Measuring Steady-State Primary Photocurrent
SIGNIFICANCE AND USE
PN Junction Diode—The steady-state photocurrent of a simple p-n junction diode is a directly measurable quantity that can be directly related to device response over a wide range of ionizing radiation. For more complex devices the junction photocurrent may not be directly related to device response.
Zener Diode— In this device, the effect of the photocurrent on the Zener voltage rather than the photocurrent itself is usually most important. The device is most appropriately tested while biased in the Zener region. In testing Zener diodes or precision voltage regulators, extra precaution must be taken to make certain the photocurrent generated in the device during irradiations does not cause the voltage across the device to change during the test.
Bipolar Transistor—As device geometries dictate that photocurrent from the base-collector junction be much greater than current from the base-emitter junction, measurements are usually made only on the collector-base junction with emitter open; however, sometimes, to obtain data for computer-aided circuit analysis, the emitter-base junction photocurrent is also measured.
Junction Field-Effect Device—A proper photocurrent measurement requires that the source be shorted (dc) to the drain during measurement of the gate-channel photocurrent. In tetrode-connected devices, the two gate-channel junctions should be monitored separately.
Insulated Gate Field-Effect Device—In this type of device, the true photocurrent is between the substrate and the channel, source, and drain regions. A current which can generate voltage that will turn on the device may be measured by the technique used here, but it is due to induced conductivity in the gate insulator and thus is not a junction photocurrent.
SCOPE
1.1 This test method covers the measurement of steady-state primary photocurrent, Ipp, generated in semiconductor devices when these devices are exposed to ionizing radiation. These procedures are intended for the measurement of photocurrents greater than 10−9 A·s/Gy(Si or Ge), in cases for which the relaxation time of the device being measured is less than 25 % of the pulse width of the ionizing source. The validity of these procedures for ionizing dose rates as great as 108Gy(Si or Ge)/s has been established. The procedures may be used for measurements at dose rates as great as 1010Gy(Si or Ge)/s; however, extra care must be taken. Above 108Gy/s, the package response may dominate the device response for any device. Additional precautions are also required when measuring photocurrents of 10−9 A·s/Gy(Si or Ge) or lower.
1.2 Setup, calibration, and test circuit evaluation procedures are also included in this test method.
1.3 Because of the variability between device types and in the requirements of different applications, the dose rate range over which any specific test is to be conducted is not given in this test method but must be specified separately.
1.4 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
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Designation: F448 − 11
Standard Test Method for
1
Measuring Steady-State Primary Photocurrent
ThisstandardisissuedunderthefixeddesignationF448;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.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. Scope 2. Referenced Documents
2
2.1 ASTM Standards:
1.1 Thistestmethodcoversthemeasurementofsteady-state
E668 Practice for Application of Thermoluminescence-
primary photocurrent, I , generated in semiconductor devices
pp
Dosimetry (TLD) Systems for Determining Absorbed
when these devices are exposed to ionizing radiation. These
DoseinRadiation-HardnessTestingofElectronicDevices
procedures are intended for the measurement of photocurrents
F526Test Method for Using Calorimeters for Total Dose
−9
greater than 10 A·s/Gy(Si or Ge), in cases for which the
Measurements in Pulsed Linear Accelerator or Flash
relaxation time of the device being measured is less than 25%
X-ray Machines
of the pulse width of the ionizing source. The validity of these
8
proceduresforionizingdoseratesasgreatas10 Gy(SiorGe)/s
3. Terminology
has been established. The procedures may be used for mea-
3.1 Definitions:
10
surements at dose rates as great as 10 Gy(Si or Ge)/s;
3.1.1 fall time, n—the time required for a signal pulse to
8
however, extra care must be taken. Above 10 Gy/s, the
drop from 90 to 10% of its steady-state value.
package response may dominate the device response for any
3.1.2 photocurrent relaxation time, n—the time required for
device.Additional precautions are also required when measur-
theradiationinducedphotocurrenttodecreaseto1/e(0.368)of
−9
ing photocurrents of 10 A·s/Gy(Si or Ge) or lower.
its initial value. The relaxation time depends upon the
1.2 Setup,calibration,andtestcircuitevaluationprocedures recombination-controlled photocurrent decay in the media,
which is often a semiconductor. The relaxation time can
are also included in this test method.
depend upon the temperature and the strength of the
1.3 Because of the variability between device types and in
irradiation/illumination.
the requirements of different applications, the dose rate range
3.1.3 primary photocurrent, n—the flow of excess charge
over which any specific test is to be conducted is not given in
carriers across a p-n junction due to ionizing radiation creating
this test method but must be specified separately.
electron-hole pairs throughout the device. The charges associ-
1.4 The values stated in SI units are to be regarded as ated with this current are only those produced in the junction
depletion region and in the bulk semiconductor material
standard. No other units of measurement are included in this
approximately one diffusion length on either side of the
standard.
depletion region (or to the end of the semiconductor material,
1.5 This standard does not purport to address all of the
whichever is shorter).
safety concerns, if any, associated with its use. It is the
3.1.4 pulse width, n—the time a pulse-amplitude remains
responsibility of the user of this standard to establish appro-
above 50% of its maximum value.
priate safety and health practices and determine the applica-
3.1.5 risetime,n—thetimerequiredforasignalpulsetorise
bility of regulatory limitations prior to use.
from 10 to 90% of its steady-state value.
4. Summary of Test Method
4.1 In this test method, the test device is irradiated in the
primary electron beam of a linear accelerator. Both the irradia-
tion pulse and junction current (Fig. 1) are displayed and
1
This test method is under the jurisdiction of ASTM Committee F01 on
Electronics and is the direct responsibility of Subcommittee F01.11 on Nuclear and
2
Space Radiation Effects. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
CurrenteditionapprovedJune1,2011.PublishedJuly2011.Originallyapproved contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
in1975asF448–75T.Lastpreviouseditionapprovedin2005asF448–99(2005). Standards volume information, refer to the standard’s Document Summary page on
DOI: 10.1520/F0448-11. the ASTM website.
Copyright © ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959. United States
1
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F448 − 11
FIG. 1 Ionization Radiation Pulse and Typical Primary Photocurrent Response
recorded. Placement of a thin, low atomic number (Z≤13) tetrode-connected devices, the two gate-channel junctions
scattering plate in the beam is recommended to improve beam should be monitored separately.
uniformity; the consequences of the use
...
This document is not anASTM standard and is intended only to provide the user of anASTM standard an indication of what changes have been made to the previous version. Because
it may not be technically possible to adequately depict all changes accurately, ASTM recommends that users consult prior editions as appropriate. In all cases only the current version
of the standard as published by ASTM is to be considered the official document.
Designation:F448–99(Reapproved2005) Designation: F448 – 11
Standard Test Method for
1
Measuring Steady-State Primary Photocurrent
ThisstandardisissuedunderthefixeddesignationF448;thenumberimmediatelyfollowingthedesignationindicatestheyearoforiginal
adoptionor,inthecaseofrevision,theyearoflastrevision.Anumberinparenthesesindicatestheyearoflastreapproval.Asuperscript
epsilon (´) indicates an editorial change since the last revision or reapproval.
1. Scope
1.1 This test method covers the measurement of steady-state primary photocurrent, I , generated in semiconductor devices
pp
whenthesedevicesareexposedtoionizingradiation.Theseproceduresareintendedforthemeasurementofphotocurrentsgreater
−9
than10 A·s/Gy(SiorGe),incasesforwhichtherelaxationtimeofthedevicebeingmeasuredislessthan25%ofthepulsewidth
8
of the ionizing source.The validity of these procedures for ionizing dose rates as great as 10 Gy(Si or Ge)/s has been established.
10
The procedures may be used for measurements at dose rates as great as 10 Gy(Si or Ge)/s; however, extra care must be taken.
8
Above 10 Gy/s the package response may dominate the device response for technologies such as complementary metal-oxide
semiconductor, (CMOS)/silicon-on sapphire (SOS). Additional precautions are also required when measuring photocurrents of
Gy/s, the package response may dominate the device response for any device. Additional precautions are also required when measuring photocurrents of10
−9
10 A·s/Gy(SiorGe)orlower.
1.2 Setup, calibration, and test circuit evaluation procedures are also included in this test method.
1.3 Because of the variability between device types and in the requirements of different applications, the dose rate range over
which any specific test is to be conducted is not given in this test method but must be specified separately.
1.4 ThevaluesstatedinInternationalSystemofUnits(SI)SIunitsaretoberegardedasstandard.Nootherunitsofmeasurement
are included in this standard.
1.5 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility
of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory
limitations prior to use.
2. Referenced Documents
2
2.1 ASTM Standards:
E668 Practice for Application of Thermoluminescence-Dosimetry (TLD) Systems for Determining Absorbed Dose in
Radiation-Hardness Testing of Electronic Devices
F526 Test Method for Using Calorimeters forTotal Dose Measurements in Pulsed LinearAccelerator or Flash X-ray Machines
3. Terminology
3.1 Definitions:
3.1.1 fall time, n—the time required for a signal pulse to drop from 90 to 10% of its steady-state value.
3.1.2 photocurrent relaxation time, n—the time required for the radiation induced photocurrent to decrease to 1/e (0.368) of its
initial value. The relaxation time depends upon the recombination-controlled photocurrent decay in the media, which is often a
semiconductor. The relaxation time can depend upon the temperature and the strength of the irradiation/illumination.
3.1.3 primary photocurrent, n—the flow of excess charge carriers across a p-n junction due to ionizing radiation creating
electron-hole pairs throughout the device. The charges associated with this current are only those produced in the junction
depletion region and in the bulk semiconductor material approximately one diffusion length on either side of the depletion region
(or to the end of the semiconductor material, whichever is shorter).
3.1.3
3.1.4 pulse width, n—the time a pulse-amplitude remains above 50% of its maximum value.
3.1.4
3.1.5 rise time, n—the time required for a signal pulse to rise from 10 to 90% of its steady-state value.
1
This test method is under the jurisdiction of ASTM Committee F01 on Electronics and is the direct responsibility of Subcommittee F01.11 on Quality and Hardness
Assurance.
Current edition approved Jan. 1, 2005. Published January 2005. Originally approved in 1975 as F448–75T. Last previous edition approved in 1999 as F448–99. DOI:
10.1520/F0448-99R05.on Nuclear and Space Radiation Effects.
CurrenteditionapprovedJune1,2011.PublishedJuly2011.Originallyapprovedin1975asF448–75T.Lastpreviouseditionapprovedin2005asF448–99(2005).DOI:
10.1520/F0448-11.
2
ForreferencedASTMstandards,visittheASTMwebsite,www.astm.org,orcontactASTMCustomerServiceatservice@astm.org.For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
Copyright © ASTM International, 100 Barr Har
...
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