ASTM F448-18
(Test Method)Standard Test Method for Measuring Steady-State Primary Photocurrent
Standard Test Method for Measuring Steady-State Primary Photocurrent
SIGNIFICANCE AND USE
5.1 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.
5.2 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.
5.3 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.
5.4 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.
5.5 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, health, and environmental practices and determine the applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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This international standard was developed in accordance with internationally recognized principles on standardization established in the Decision on Principles for the
Development of International Standards, Guides and Recommendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
Designation: F448 − 18
Standard Test Method for
1
Measuring Steady-State Primary Photocurrent
This standard is issued under the fixed designation F448; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
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
1.1 This test method covers the measurement of steady-state 2.1 ASTM Standards:
primary photocurrent, I , generated in semiconductor devices E668 Practice for Application of Thermoluminescence-
pp
when these devices are exposed to ionizing radiation. These Dosimetry (TLD) Systems for Determining Absorbed
procedures are intended for the measurement of photocurrents Dose in Radiation-Hardness Testing of Electronic Devices
−9
greater than 10 A·s/Gy(Si or Ge), in cases for which the F526 Test Method for Using Calorimeters for Total Dose
relaxation time of the device being measured is less than 25 % Measurements in Pulsed Linear Accelerator or Flash
of the pulse width of the ionizing source. The validity of these X-ray Machines
8
procedures for ionizing dose rates as great as 10 Gy(Si or Ge)/s
3. Terminology
has been established. The procedures may be used for mea-
10
surements at dose rates as great as 10 Gy(Si or Ge)/s; 3.1 Definitions:
8
however, extra care must be taken. Above 10 Gy/s, the 3.1.1 fall time, n—the time required for a signal pulse to
package response may dominate the device response for any drop from 90 to 10 % of its steady-state value.
device. Additional precautions are also required when measur-
3.1.2 photocurrent relaxation time, n—the time required for
−9
ing photocurrents of 10 A·s/Gy(Si or Ge) or lower.
the radiation induced photocurrent to decrease to 1/e (0.368) of
its initial value. The relaxation time depends upon the
1.2 Setup, calibration, and test circuit evaluation procedures
recombination-controlled photocurrent decay in the media,
are also included in this test method.
which is often a semiconductor. The relaxation time can
1.3 Because of the variability between device types and in
depend upon the temperature and the strength of the
the requirements of different applications, the dose rate range
irradiation/illumination.
over which any specific test is to be conducted is not given in
3.1.3 primary photocurrent, n—the flow of excess charge
this test method but must be specified separately.
carriers across a p-n junction due to ionizing radiation creating
1.4 The values stated in SI units are to be regarded as
electron-hole pairs throughout the device. The charges associ-
standard. No other units of measurement are included in this
ated with this current are only those produced in the junction
standard.
depletion region and in the bulk semiconductor material
1.5 This standard does not purport to address all of the
approximately one diffusion length on either side of the
safety concerns, if any, associated with its use. It is the
depletion region (or to the end of the semiconductor material,
responsibility of the user of this standard to establish appro-
whichever is shorter).
priate safety, health, and environmental practices and deter-
3.1.4 pulse width, n—the time a pulse-amplitude remains
mine the applicability of regulatory limitations prior to use.
above 50 % of its maximum value.
1.6 This international standard was developed in accor-
3.1.5 rise time, n—the time required for a signal pulse to rise
dance with internationally recognized principles on standard-
from 10 to 90 % of its steady-state value.
ization established in the Decision on Principles for the
Development of International Standards, Guides and Recom-
4. Summary of Test Method
mendations issued by the World Trade Organization Technical
4.1 In this test method, the test device is irradiated in the
Barriers to Trade (TBT) Committee.
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 E10 on Nuclear
Technology and Applications and is the direct responsibility of Subcommittee
2
E10.07 on Radiation Dosimetry for Radiation Effects on Materials and Devices. For referenced ASTM standards, visit the ASTM website, www.astm.org, or
Current edition approved March 1, 2018. Published April 2018. Originally contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM
approved in 1975 as F448 – 75 T. Last
...
This document is not an ASTM standard and is intended only to provide the user of an ASTM 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 − 11 F448 − 18
Standard Test Method for
1
Measuring Steady-State Primary Photocurrent
This standard is issued under the fixed designation F448; the number immediately following the designation indicates the year of original
adoption or, in the case of revision, the year of last revision. A number in parentheses indicates the year of last reapproval. A superscript
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
1.1 This test method covers the measurement of steady-state primary photocurrent, I , generated in semiconductor devices
pp
when these devices are exposed to ionizing radiation. These procedures are intended for the measurement of photocurrents greater
−9
than 10 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
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 any device. Additional precautions are also required
−9
when measuring photocurrents of 10 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 safety, health, and healthenvironmental practices and determine the
applicability of regulatory limitations prior to use.
1.6 This international standard was developed in accordance with internationally recognized principles on standardization
established in the Decision on Principles for the Development of International Standards, Guides and Recommendations issued
by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
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 for Total Dose Measurements in Pulsed Linear Accelerator 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).
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 Space
Radiation Effects.
Current edition approved June 1, 2011March 1, 2018. Published July 2011April 2018. Originally approved in 1975 as F448 – 75 T. Last previous edition approved in
20052011 as F448 – 99F448 – 11.(2005). DOI: 10.1520/F0448-11.10.1520/F0448-18.
2
For referenced ASTM standards, visit the ASTM website, www.astm.org, or contact ASTM Customer Service at service@astm.org. For Annual Book of ASTM Standards
volume information, refer to the standard’s Document Summary page on the ASTM website.
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...
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