ASTM F358-83(2002)

NOTICE: This standard has either been superseded and replaced by a new version or withdrawn.
Contact ASTM International (www.astm.org) for the latest information
Designation:F 358–83(Reapproved2002)
Standard Test Method for
Wavelength of Peak Photoluminescence and the
Corresponding Composition of Gallium Arsenide Phosphide
Wafers
This standard is issued under the fixed designation F 358; the number immediately following the designation indicates the year of
original adoption or, in the case of revision, the year of last revision.Anumber in parentheses indicates the year of last reapproval.A
superscript epsilon (e) indicates an editorial change since the last revision or reapproval.
1. Scope 1.7 This standard does not purport to address all of the
safety concerns, if any, associated with its use. It is the
1.1 This test method covers the techniques used to deter-
responsibility of the user of this standard to establish appro-
mine the wavelength of the photoluminescence peak and the
priate safety and health practices and determine the applica-
mole percent phosphorus content of gallium arsenide phos-
bility of regulatory limitations prior to use. Specific hazard
phide, GaAs P .
(1x) x
statements are given in Section 7.
1.2 Photoluminescence measurements indicate the compo-
sition only in the illuminated region and only within a very
2. Referenced Documents
short distance from the surface, a distance limited by the
2.1 ASTM Standards:
penetration of the radiation and the diffusion length of the
D 1125 Test Methods for Electrical Conductivity and Re-
photo-generated carriers, as contrasted to X-ray measurements
sistivity of Water
which sample a much deeper volume.
E 177 Practice for Use of the Terms Precision and Bias in
1.3 This test method is limited by the surface preparation
ASTM Test Methods
procedure to application to epitaxial layers of the semiconduc-
E 275 Practice for Describing and Measuring Performance
tor grown in a vapor-phase reactor on a flat substrate. It is
of Ultraviolet, Visible, and Near-Infrared Spectrophotom-
directly applicable to n-type GaAs P with the wavelength,
(1x) x
eters
l , of the photoluminescence peak in the range from 640 to
PL
2.2 SEMI Standard:
670 nm, corresponding to mole percent phosphorus in the
C1 Specifications for Reagents
range from 36 to 42% (x=0.36 to 0.42). The calibration data
provided for the determination of x from l is applicable to
PL
3. Summary of Test Method
material doped with tellurium or selenium at concentrations in
16 18 3 3.1 The photoluminescence spectrum is recorded for the
the range from 10 to 10 atoms/cm .
wavelength range from 600 to 750 nm and the wavelength,
1.4 The principle of this test method is more broadly
l , at which maximum luminescence occurs is determined by
PL
applicable. Other material preparation methods may require
means of a graphical construction. The phosphorus content is
differentsurfacetreatments.Extensiontootherdopants,doping
thendeterminedbymeansofacalibrationcurverelating l to
PL
ranges or composition ranges requires further work to relate
the amount of phosphorus as determined by X-ray measure-
l to the phosphorus content as determined by X-ray mea-
PL
ment of the precise dimension of the unit cell.
surementsoftheprecisedimensionsoftheunitcelluponwhich
the calibration data are based. It is essential that calibration
4. Interferences
specimens have uniform composition in the volume sampled.
4.1 The apparent position of the photoluminescence peak
1.5 This test method is essentially nondestructive. It re-
can be distorted by the spectral response characteristics of the
quires a light etching of the sample to be measured. The
detectionsystem,and,inparticular,bythespectralresponseof
removal of a layer of material approximately 0.5 to 1.0 µm in
the photomultiplier. Therefore, the detector to be used for
thickness is required. This etching does not degrade the
measurementsonaspecificrangeofalloycompositionsshould
specimen in that devices can still be fabricated from it.
be chosen so that the corresponding range of l falls in a
PL
1.6 This test method is applicable to process control in the
region where the detector response is changing slowly.
preparation of materials and to materials acceptance.
Annual Book of ASTM Standards, Vol 11.01.
1 3
This test method is under the jurisdiction of Committee F01on Electronics and Annual Book of ASTM Standards, Vol 14.02.
is the direct responsibility of Subcommittee F01.15 on Compound Semiconductors. Annual Book of ASTM Standards, Vol 03.06.
Current edition approved Nov. 28, 1983. Published July 1984. Originally AvailablefromSemiconductorEquipmentandMaterialsInstitute,625EllisSt.,
published as F358–72T. Last previous edition F358–73(1983). Suite 212, Mountain View, CA 94043.
Copyright ©ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA19428-2959, United States.
F 358–83 (2002)
4.2 The presence of strong background radiation and, in illuminating radiation be kept out of the monochromator either
particular,ofbackgroundradiationwhichchangesrapidlywith by filtration or by positioning of the specimen with respect to
wavelength can displace the apparent position of the photolu- the illuminating radiation so that the specularly reflected rays
minescence peak. Users should, therefore, assure themselves do not enter the collection system, or both. Fig. 1 shows a
that the background radiation is small by replacing the sample schematic diagram of a system in which the effects of the
with a mirror and scanning through the wavelength range of reflected illumination are minimized by suitable positioning.
interest. The resulting trace should be a small fraction of the
5.2.4 Monochromator, designed to operate in the 600 to
photoluminescence signal.
750-nm wavelength range with wavelength accuracy and
4.3 Since the energy of the band gap of most semiconduc-
repeatability of 0.5 nm as determined in accordance with
tors, and of GaAs P in particular, varies with temperature,
Practice E275.
(1x) x
the measurement of l can be perturbed if the incident power
PL
5.2.5 Detector—A photomultiplier tube with constant or
density from the illuminator is high enough to locally heat the
slowly varying spectral sensitivity throughout the range of
specimen. Users of this technique should, therefore, assure
interest.
themselves that they are not using too high a power density by
NOTE 1—In the absence of data to the contrary, a variation of no more
measuring l asafunctionofincidentpower,byusingneutral
PL
than 10% in sensitivity in any 10-nm region of the spectral range of
density filters or other means. There should be no variation if
interest as determined from the manufacturer’s published sensitivity
the power level is low enough; l will shift to longer
PL
curves for the tube shall be deemed acceptable.
wavelengths with increasing power if power is excessive.
5.2.6 Detector Electronics—Electronics capable of supply-
5. Apparatus
ing the high voltage required by the photomultiplier and of
detectingandamplifyingtheanodecurrentfromthephotomul-
5.1 For Specimen Preparation—Chemical laboratory appa-
tiplier so that it can drive the chart-recorder electronics.
ratus such as plastic beakers, plastic-coated tweezers suitable
for use with acids, and adequate facilities for handling and 5.2.7 Detection System Sensitivity—The detection system,
consisting of collection optics, monochromator, detector, and
disposing of acids and their vapors must be provided.
detector electronics, should be capable of responding to a
5.2 For Measurement of Specimen Photoluminescence (see
−6
luminescencesignalof10 mW/nmorlessascalculatedfrom
Fig. 1):
the following equation:
5.2.1 Light Source, a 200-W mercury or xenon arc lamp, a
laser, or other source, with suitable filtration and focusing lens 2
B 5Sf /~WmTDG!
to illuminate the specimen with radiation at a wavelength
shorter than 600 nm with a total incident energy of at least 1 where:
mW in an area 1 mm or less. B = luminescence signal, mW/nm,
S = minimum detectable signal at the output electronics,
5.2.2 Specimen Support—A holder that can support the
typically 10 times the detector dark current, mA,
specimeninsuchapositionthattheincidentradiationstrikesit
f = the lesser of t
...