F01.15 - Compound Semiconductors

SIGNIFICANCE AND USE
4.1 In order to choose the proper material for producing semiconductor devices, knowledge of material properties such as resistivity, Hall coefficient, and Hall mobility is useful. Under certain conditions, as outlined in the Appendix, other useful quantities for materials specification, including the charge carrier density and the drift mobility, can be inferred.
SCOPE
1.1 These test methods cover two procedures for measuring the resistivity and Hall coefficient of single-crystal semiconductor specimens. These test methods differ most substantially in their test specimen requirements.  
1.1.1 Test Method A, van der Pauw (1) 2—This test method requires a singly connected test specimen (without any isolated holes), homogeneous in thickness, but of  arbitrary shape. The contacts must be sufficiently small and located at the periphery of the specimen. The measurement is most easily interpreted for an isotropic semiconductor whose conduction is dominated by a single type of carrier.  
1.1.2 Test Method B, Parallelepiped or Bridge-Type—This test method requires a specimen homogeneous in thickness and of specified  shape. Contact requirements are specified for both the parallelepiped and bridge geometries. These test specimen geometries are desirable for anisotropic semiconductors for which the measured parameters depend on the direction of current flow. The test method is also most easily interpreted when conduction is dominated by a single type of carrier.  
1.2 These test methods do not provide procedures for shaping, cleaning, or contacting specimens; however, a procedure for verifying contact quality is given.  
Note 1: Practice F418 covers the preparation of gallium arsenide phosphide specimens.  
1.3 The method in Practice F418 does not provide an interpretation of the results in terms of basic semiconductor properties (for example, majority and minority carrier mobilities and densities). Some general guidance, applicable to certain semiconductors and temperature ranges, is provided in the Appendix. For the most part, however, the interpretation is left to the user.  
1.4 Interlaboratory tests of these test methods (Section 19) have been conducted only over a limited range of resistivities and for the semiconductors, germanium, silicon, and gallium arsenide. However, the method is applicable to other semiconductors provided suitable specimen preparation and contacting procedures are known. The resistivity range over which the method is applicable is limited by the test specimen geometry and instrumentation sensitivity.  
1.5 The values stated in acceptable metric units are to be regarded as the standard. The values given in parentheses are for information only. (See also 3.1.4.)  
1.6 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.

SIGNIFICANCE AND USE
In order to choose the proper material for producing semiconductor devices, knowledge of material properties such as resistivity, Hall coefficient, and Hall mobility is useful. Under certain conditions, as outlined in the Appendix, other useful quantities for materials specification, including the charge carrier density and the drift mobility, can be inferred.
SCOPE
1.1 These test methods cover two procedures for measuring the resistivity and Hall coefficient of single-crystal semiconductor specimens. These test methods differ most substantially in their test specimen requirements.  
1.1.1 Test Method A, van der Pauw (1) —This test method requires a singly connected test specimen (without any isolated holes), homogeneous in thickness, but of  arbitrary shape. The contacts must be sufficiently small and located at the periphery of the specimen. The measurement is most easily interpreted for an isotropic semiconductor whose conduction is dominated by a single type of carrier.
1.1.2 Test Method B, Parallelepiped or Bridge-Type—This test method requires a specimen homogeneous in thickness and of specified  shape. Contact requirements are specified for both the parallelepiped and bridge geometries. These test specimen geometries are desirable for anisotropic semiconductors for which the measured parameters depend on the direction of current flow. The test method is also most easily interpreted when conduction is dominated by a single type of carrier.  
1.2 These test methods do not provide procedures for shaping, cleaning, or contacting specimens; however, a procedure for verifying contact quality is given.
Note 1—Practice F 418 covers the preparation of gallium arsenide phosphide specimens.  
1.3 The method in Practice F 418 does not provide an interpretation of the results in terms of basic semiconductor properties (for example, majority and minority carrier mobilities and densities). Some general guidance, applicable to certain semiconductors and temperature ranges, is provided in the Appendix. For the most part, however, the interpretation is left to the user.
1.4 Interlaboratory tests of these test methods (Section 19) have been conducted only over a limited range of resistivities and for the semiconductors, germanium, silicon, and gallium arsenide. However, the method is applicable to other semiconductors provided suitable specimen preparation and contacting procedures are known. The resistivity range over which the method is applicable is limited by the test specimen geometry and instrumentation sensitivity.
1.5 The values stated in acceptable metric units are to be regarded as the standard. The values given in parentheses are for information only. (See also 3.1.4.)
1.6 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.

SIGNIFICANCE AND USE
The use of GaAs for semiconductor devices requires a consistent atomic lattice structure. However, lattice or crystal line defects of various types and quantities are always present, and rarely homogeneously distributed. It is important to determine the mean value and the spatial distribution of the etch pit density.
SCOPE
1.1 This test method is used to determine whether an ingot or wafer of gallium arsenide is monocrystalline and, if so, to measure the etch pit density and to judge the nature of crystal imperfections. To the extent possible, it follows the corresponding test method for silicon, Test Method F47.  Test Method F47 also presents the definition of many crystallographic terms, applicable to this test method.  
1.2 This procedure is suitable for gallium arsenide crystals with etch pit densities between 0 and 200000/cm2.  
1.3 Gallium arsenide, either doped or undoped, and with various electrical properties, may be evaluated by this test method. The front surface normal direction of the sample must be parallel to the  within + 5° and must be suitably prepared by polishing or etching, or both. Unremoved processing damage may lead to etch pits, obscuring the quality of the bulk crystal.  
1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 8.

SCOPE
1.1 This destructive test method determines whether a given sample of semi-insulating gallium arsenide (GaAs) will remain semi-insulating after exposure to the high temperatures normally required for the activation of implanted layers.
1.2 The underlying assumption is that other wafers of GaAs, whose manufacturing history was the same as the wafer from which the test sample was taken, will respond to high temperatures in like manner.
1.3 The emphasis in this test method is on simplicity and safety of apparatus, and on securing a measurement that is independent of the apparatus used.
1.4 This test method is directly applicable to uncapped and unimplanted samples of GaAs. However, users of this test method may extend it to capped or implanted samples, or both, in which case a controlled test of capped versus uncapped samples, or implanted versus unimplanted samples, is recommended.
1.5 This test method detects impurities "from the bulk" (that is, from within the GaAs wafer) that will likely affect the electrical behavior of devices formed on the surface of the wafer. This test method is not sensitive to surface impurities or process-induced impurities, except as interferences (see Interferences).
1.6

SIGNIFICANCE AND USE
In order to choose the proper material for producing semiconductor devices, knowledge of material properties such as resistivity, Hall coefficient, and Hall mobility is useful. Under certain conditions, as outlined in the Appendix, other useful quantities for materials specification, including the charge carrier density and the drift mobility, can be inferred.
SCOPE
1.1 These test methods cover two procedures for measuring the resistivity and Hall coefficient of single-crystal semiconductor specimens. These test methods differ most substantially in their test specimen requirements.
1.1.1 Test Method A, van der Pauw (1) -This test method requires a singly connected test specimen (without any isolated holes), homogeneous in thickness, but of  arbitrary shape. The contacts must be sufficiently small and located at the periphery of the specimen. The measurement is most easily interpreted for an isotropic semiconductor whose conduction is dominated by a single type of carrier.
1.1.2 Test Method B, Parallelepiped or Bridge—TypeThis test method requires a specimen homogeneous in thickness and of specified  shape. Contact requirements are specified for both the parallelepiped and bridge geometries. These test specimen geometries are desirable for anisotropic semiconductors for which the measured parameters depend on the direction of current flow. The test method is also most easily interpreted when conduction is dominated by a single type of carrier.
1.2 These test methods do not provide procedures for shaping, cleaning, or contacting specimens; however, a procedure for verifying contact quality is given.
Note 1—Practice F 418 covers the preparation of gallium arsenide phosphide specimens.
1.3 The method in Practice F 418 does not provide an interpretation of the results in terms of basic semiconductor properties (for example, majority and minority carrier mobilities and densities). Some general guidance, applicable to certain semiconductors and temperature ranges, is provided in the Appendix. For the most part, however, the interpretation is left to the user.
1.4 Interlaboratory tests of these test methods (Section 19) have been conducted only over a limited range of resistivities and for the semiconductors, germanium, silicon, and gallium arsenide. However, the method is applicable to other semiconductors provided suitable specimen preparation and contacting procedures are known. The resistivity range over which the method is applicable is limited by the test specimen geometry and instrumentation sensitivity.
1.5 The values stated in acceptable metric units are to be regarded as the standard. The values given in parentheses are for information only. (See also 3.1.4.)
1.6 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.

SCOPE
1.1 These test methods cover two procedures for measuring the resistivity and Hall coefficient of single-crystal semiconductor specimens. These test methods differ most substantially in their test specimen requirements.
1.1.1 Test Method A, van der Pauw (1) -This test method requires a singly connected test specimen (without any isolated holes), homogeneous in thickness, but of  arbitrary shape. The contacts must be sufficiently small and located at the periphery of the specimen. The measurement is most easily interpreted for an isotropic semiconductor whose conduction is dominated by a single type of carrier.
1.1.2 Test Method B, Parallelepiped or Bridge—TypeThis test method requires a specimen homogeneous in thickness and of specified  shape. Contact requirements are specified for both the parallelepiped and bridge geometries. These test specimen geometries are desirable for anisotropic semiconductors for which the measured parameters depend on the direction of current flow. The test method is also most easily interpreted when conduction is dominated by a single type of carrier.
1.2 These test methods do not provide procedures for shaping, cleaning, or contacting specimens; however, a procedure for verifying contact quality is given.
Note 1—Practice F 418 covers the preparation of gallium arsenide phosphide specimens.
1.3 The method in Practice F 418 does not provide an interpretation of the results in terms of basic semiconductor properties (for example, majority and minority carrier mobilities and densities). Some general guidance, applicable to certain semiconductors and temperature ranges, is provided in the Appendix. For the most part, however, the interpretation is left to the user.
1.4 Interlaboratory tests of these test methods (Section 19) have been conducted only over a limited range of resistivities and for the semiconductors, germanium, silicon, and gallium arsenide. However, the method is applicable to other semiconductors provided suitable specimen preparation and contacting procedures are known. The resistivity range over which the method is applicable is limited by the test specimen geometry and instrumentation sensitivity.
1.5 The values stated in acceptable metric units are to be regarded as the standard. The values given in parentheses are for information only. (See also 3.1.4.)
1.6 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.

SCOPE
1.1 This test method covers the techniques used to determine the wavelength of the photoluminescence peak and the mole percent phosphorus content of gallium arsenide phosphide, GaAs(1 x)Px.
1.2 Photoluminescence measurements indicate the composition only in the illuminated region and only within a very short distance from the surface, a distance limited by the penetration of the radiation and the diffusion length of the photo-generated carriers, as contrasted to X-ray measurements which sample a much deeper volume.
1.3 This test method is limited by the surface preparation procedure to application to epitaxial layers of the semiconductor grown in a vapor-phase reactor on a flat substrate. It is directly applicable to n-type GaAs(1x)Px with the wavelength, PL, of the photoluminescence peak in the range from 640 to 670 nm, corresponding to mole percent phosphorus in the range from 36 to 42 % ( x = 0.36 to 0.42). The calibration data provided for the determination of x from P L is applicable to material doped with tellurium or selenium at concentrations in the range from 1016 to 1018 atoms/cm3.
1.4 The principle of this test method is more broadly applicable. Other material preparation methods may require different surface treatments. Extension to other dopants, doping ranges or composition ranges requires further work to relate PL to the phosphorus content as determined by X-ray measurements of the precise dimensions of the unit cell upon which the calibration data are based. It is essential that calibration specimens have uniform composition in the volume sampled.
1.5 This test method is essentially nondestructive. It requires a light etching of the sample to be measured. The removal of a layer of material approximately 0.5 to 1.0 m in thickness is required. This etching does not degrade the specimen in that devices can still be fabricated from it.
1.6 This test method is applicable to process control in the preparation of materials and to materials acceptance.
1.7 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. Specific hazard statements are given in Section 7.

SCOPE
1.1 This practice covers a procedure to be followed to free the constant composition region of epitaxially grown gallium arsenide phosphide, GaAs(1x)Px, from the substrate and graded region on which it was grown in order to measure the electrical properties of only the constant composition region, which is typically 30 to 100 m thick. It also sets forth two alternative procedures to be followed to make electrical contact to the specimen.
1.2 It is intended that this practice be used in conjunction with Test Methods F 76.
1.3 The specific parameters set forth in this recommended practice are appropriate for GaAs0. 62P0. 38, but they can be applied, with changes in etch times, to material with other compositions.
1.4 This practice does not deal with making or interpreting the Hall measurement on a specimen prepared as described herein, other than to point out the existence and possible effects due to the distribution of the free carriers among the two conduction band minima.
1.5 This practice can also be followed in the preparation of specimens of the constant composition region for light absorption measurements or for mass or emission spectrometric analysis.
1.6 This practice becomes increasingly difficult to apply as specimens become thinner.
1.7 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. For hazard statement, see Section 9 and 11.9.2.4.

SIGNIFICANCE AND USE
4.1 In order to choose the proper material for producing semiconductor devices, knowledge of material properties such as resistivity, Hall coefficient, and Hall mobility is useful. Under certain conditions, as outlined in the Appendix, other useful quantities for materials specification, including the charge carrier density and the drift mobility, can be inferred.
SCOPE
1.1 These test methods cover two procedures for measuring the resistivity and Hall coefficient of single-crystal semiconductor specimens. These test methods differ most substantially in their test specimen requirements.  
1.1.1 Test Method A, van der Pauw (1) 2—This test method requires a singly connected test specimen (without any isolated holes), homogeneous in thickness, but of  arbitrary shape. The contacts must be sufficiently small and located at the periphery of the specimen. The measurement is most easily interpreted for an isotropic semiconductor whose conduction is dominated by a single type of carrier.  
1.1.2 Test Method B, Parallelepiped or Bridge-Type—This test method requires a specimen homogeneous in thickness and of specified  shape. Contact requirements are specified for both the parallelepiped and bridge geometries. These test specimen geometries are desirable for anisotropic semiconductors for which the measured parameters depend on the direction of current flow. The test method is also most easily interpreted when conduction is dominated by a single type of carrier.  
1.2 These test methods do not provide procedures for shaping, cleaning, or contacting specimens; however, a procedure for verifying contact quality is given.  
Note 1: Practice F418 covers the preparation of gallium arsenide phosphide specimens.  
1.3 The method in Practice F418 does not provide an interpretation of the results in terms of basic semiconductor properties (for example, majority and minority carrier mobilities and densities). Some general guidance, applicable to certain semiconductors and temperature ranges, is provided in the Appendix. For the most part, however, the interpretation is left to the user.  
1.4 Interlaboratory tests of these test methods (Section 19) have been conducted only over a limited range of resistivities and for the semiconductors, germanium, silicon, and gallium arsenide. However, the method is applicable to other semiconductors provided suitable specimen preparation and contacting procedures are known. The resistivity range over which the method is applicable is limited by the test specimen geometry and instrumentation sensitivity.  
1.5 The values stated in acceptable metric units are to be regarded as the standard. The values given in parentheses are for information only. (See also 3.1.4.)  
1.6 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.  
1.7 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.
WITHDRAWN RATIONALE
These test methods covered two procedures for measuring the resistivity and Hall coefficient of single-crystal semiconductor specimens.
Formerly under the jurisdiction of Committee F01 on Electronics, these test methods were withdrawn in November 2023. This standard is being withdrawn without replacement because Committee F01 was disbanded.

SIGNIFICANCE AND USE
The use of GaAs for semiconductor devices requires a consistent atomic lattice structure. However, lattice or crystal line defects of various types and quantities are always present, and rarely homogeneously distributed. It is important to determine the mean value and the spatial distribution of the etch pit density.
SCOPE
1.1 This test method is used to determine whether an ingot or wafer of gallium arsenide is monocrystalline and, if so, to measure the etch pit density and to judge the nature of crystal imperfections. To the extent possible, it follows the corresponding test method for silicon, Test Method F 47. Test Method F 47 also presents the definition of many crystallographic terms, applicable to this test method.
1.2 This procedure is suitable for gallium arsenide crystals with etch pit densities between 0 and 200 000/cm2.  
1.3 Gallium arsenide, either doped or undoped, and with various electrical properties, may be evaluated by this test method. The front surface normal direction of the sample must be parallel to the 001> within ± 5° and must be suitably prepared by polishing or etching, or both. Unremoved processing damage may lead to etch pits, obscuring the quality of the bulk crystal.
1.4 This standard does not purport to address all of the safety problems, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and to determine the applicability of regulatory limitations prior to use. Specific hazard statements are given in Section 8.
WITHDRAWN RATIONALE
This test method is used to determine whether an ingot or wafer of gallium arsenide is monocrystalline and, if so, to measure the etch pit density and to judge the nature of crystal imperfections.
Formerly under the jurisdiction of Committee F01 on Electronics, this test method was withdrawn in January 2016 in accordance with section 10.6.3 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.

SIGNIFICANCE AND USE
The measurements described in this guide can significantly affect the function of the sapphire substrate.
Substrates with excessive form errors in the free state may cause processing errors in production.
The restrained state of the substrate is intended to simulate as closely as possible the form that the substrate will take in one of its intended uses. During processing, one surface of the substrate is sometimes forcibly restrained to a flat state through either vacuum or adhesion to a flat surface. The measurements in the clamped state are intended to model the form of the front surface of the substrate when the back surface is constrained to the reference plane. The form in the clamped state may have a direct impact on the performance of the substrate in use.
The user should determine whether the unrestrained or restrained measurements are most pertinent to the application and specify the appropriate parameters accordingly.
Knowledge of these characteristics can help the producer and consumer determine if the dimensional characteristics of a specimen substrate satisfy given geometrical requirements.
This guide is suitable for sapphire substrates in the as-sliced, lapped, polished, or other condition. Refer to SEMI M3 for substrate specifications.
Until the results of a planned interlaboratory evaluation of this guide are established, use of this guide for commercial transactions is not recommended unless the parties to the test establish the degree of correlation that can be obtained.
SCOPE
1.1 This guide covers a nondestructive procedure to determine the form of clean, dry sapphire substrates.
1.2 This guide is applicable to substrates 25 mm or larger in diameter, with a minimum thickness of 100 μm. This guide is independent of surface finish.
1.3 The measurements described in this guide may be applied to the entire global surface of the substrate, or to smaller localized areas.
1.4 The value of the measurements described in this guide will be affected by the amount of edge exclusion (that is, the area around the perimeter of the part which is ignored). The amount excluded should be agreed upon by the producer and consumer using 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 requirements prior to use.
WITHDRAWN RATIONALE
This guide covers a nondestructive procedure to determine the form of clean, dry sapphire substrates.
Formerly under the jurisdiction of Committee F01 on Electronics and Subcommittee F01.15 on Compound Semiconductors, this guide was withdrawn in July 2011 without replacement due to its limited use by the industry.

SCOPE
1.1 This test method covers the techniques used to determine the wavelength of the photoluminescence peak and the mole percent phosphorus content of gallium arsenide phosphide, GaAs(1 x)Px.
1.2 Photoluminescence measurements indicate the composition only in the illuminated region and only within a very short distance from the surface, a distance limited by the penetration of the radiation and the diffusion length of the photo-generated carriers, as contrasted to X-ray measurements which sample a much deeper volume.
1.3 This test method is limited by the surface preparation procedure to application to epitaxial layers of the semiconductor grown in a vapor-phase reactor on a flat substrate. It is directly applicable to n-type GaAs(1x)Px with the wavelength, PL, of the photoluminescence peak in the range from 640 to 670 nm, corresponding to mole percent phosphorus in the range from 36 to 42 % ( x = 0.36 to 0.42). The calibration data provided for the determination of x from P L is applicable to material doped with tellurium or selenium at concentrations in the range from 1016 to 1018 atoms/cm3.
1.4 The principle of this test method is more broadly applicable. Other material preparation methods may require different surface treatments. Extension to other dopants, doping ranges or composition ranges requires further work to relate PL to the phosphorus content as determined by X-ray measurements of the precise dimensions of the unit cell upon which the calibration data are based. It is essential that calibration specimens have uniform composition in the volume sampled.
1.5 This test method is essentially nondestructive. It requires a light etching of the sample to be measured. The removal of a layer of material approximately 0.5 to 1.0 m in thickness is required. This etching does not degrade the specimen in that devices can still be fabricated from it.
1.6 This test method is applicable to process control in the preparation of materials and to materials acceptance.
1.7 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. Specific hazard statements are given in Section 7.
WITHDRAWN RATIONALE
Formerly under the jurisdiction of Committee F01 on Electronics, this test method was withdrawn in June 2008 in accordance with section 10.5.3.1 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.

SIGNIFICANCE AND USE
The efficiency of light-emitting diodes is known to vary with the carrier density of the starting material. This procedure provides a technique to prepare specimens in which the Hall carrier density can be measured in a region typical of that in which devices are fabricated. This quantity, which is related to the carrier density, can be used directly as a quality control parameter.
Mobility is a function of a number of parameters of a semiconductor, including ionized impurity density, compensation, and lattice defects, some or all of which may be relatable to material quality as reflected in device quality. Use of this procedure makes the measurement of the mobility of the constant composition region possible.
Since in GaAs (1−x)Px with x near 0.38, as is most often used for light-emitting diodes, the direct (000 or Γ) minimum and the indirect (100 or X) minima are within a few millielectronvolts in energy of each other, both are populated with current-carrying electrons. The mobility in the two bands is significantly different, and the relative population of the two is dependent upon the precise composition (x value), doping level, and temperature. Therefore, both Hall coefficient and Hall mobility must be interpreted with care (2,3). In particular, a measurement of Hall carrier density will not agree with a carrier density measurement on the same specimen made by capacitance-voltage techniques. Nevertheless, if the intent of measuring the carrier density of purchased or grown specimens is to find those which are optimum for diode fabrication, Hall measurements can be of value because a curve of efficiency versus Hall carrier density can be derived for the device process to be used based upon data taken on specimens prepared in accordance with this procedure.
SCOPE
1.1 This practice covers a procedure to be followed to free the constant composition region of epitaxially grown gallium arsenide phosphide, GaAs(1x)Px, from the substrate and graded region on which it was grown in order to measure the electrical properties of only the constant composition region, which is typically 30 to 100 m thick. It also sets forth two alternative procedures to be followed to make electrical contact to the specimen.
1.2 It is intended that this practice be used in conjunction with Test Methods F 76.
1.3 The specific parameters set forth in this recommended practice are appropriate for GaAs0. 62P0. 38, but they can be applied, with changes in etch times, to material with other compositions.
1.4 This practice does not deal with making or interpreting the Hall measurement on a specimen prepared as described herein, other than to point out the existence and possible effects due to the distribution of the free carriers among the two conduction band minima.
1.5 This practice can also be followed in the preparation of specimens of the constant composition region for light absorption measurements or for mass or emission spectrometric analysis.
1.6 This practice becomes increasingly difficult to apply as specimens become thinner.
1.7 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. For hazard statement, see Section 9 and 11.9.2.4.
WITHDRAWN RATIONALE
Formerly under the jurisdiction of Committee F01 on Electronics, this practice was withdrawn in June 2008 in accordance with section 10.5.3.1 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.

SCOPE
1.1 This destructive test method determines whether a given sample of semi-insulating gallium arsenide (GaAs) will remain semi-insulating after exposure to the high temperatures normally required for the activation of implanted layers.
1.2 The underlying assumption is that other wafers of GaAs, whose manufacturing history was the same as the wafer from which the test sample was taken, will respond to high temperatures in like manner.
1.3 The emphasis in this test method is on simplicity and safety of apparatus, and on securing a measurement that is independent of the apparatus used.
1.4 This test method is directly applicable to uncapped and unimplanted samples of GaAs. However, users of this test method may extend it to capped or implanted samples, or both, in which case a controlled test of capped versus uncapped samples, or implanted versus unimplanted samples, is recommended.
1.5 This test method detects impurities "from the bulk" (that is, from within the GaAs wafer) that will likely affect the electrical behavior of devices formed on the surface of the wafer. This test method is not sensitive to surface impurities or process-induced impurities, except as interferences (see Interferences).
1.6
WITHDRAWN RATIONALE
Formerly under the jurisdiction of Committee F01 on Electronics, this practice was withdrawn in June 2008 in accordance with section 10.5.3.1 of the Regulations Governing ASTM Technical Committees, which requires that standards shall be updated by the end of the eighth year since the last approval date.