ASTM_F_358_-_83_2002.pdf

Designation:F 358 83(Reapproved 2002)Standard Test Method forWavelength of Peak Photoluminescence and theCorresponding Composition of Gallium Arsenide PhosphideWafers1This standard is issued under the fixed designation F 358;the number immediately following the designation indicates the year oforiginal adoption or,in the case of revision,the year of last revision.A number in parentheses indicates the year of last reapproval.Asuperscript epsilon(e)indicates an editorial change since the last revision or reapproval.1.Scope1.1 This test method covers the techniques used to deter-mine the wavelength of the photoluminescence peak and themole percent phosphorus content of gallium arsenide phos-phide,GaAs(1x)Px.1.2 Photoluminescence measurements indicate the compo-sition only in the illuminated region and only within a veryshort distance from the surface,a distance limited by thepenetration of the radiation and the diffusion length of thephoto-generated carriers,as contrasted to X-ray measurementswhich sample a much deeper volume.1.3 This test method is limited by the surface preparationprocedure to application to epitaxial layers of the semiconduc-tor grown in a vapor-phase reactor on a flat substrate.It isdirectly applicable to n-type GaAs(1x)Pxwith the wavelength,lPL,of the photoluminescence peak in the range from 640 to670 nm,corresponding to mole percent phosphorus in therange from 36 to 42%(x=0.36 to 0.42).The calibration dataprovided for the determination of x from lPLis applicable tomaterial doped with tellurium or selenium at concentrations inthe range from 1016to 1018atoms/cm3.1.4 The principle of this test method is more broadlyapplicable.Other material preparation methods may requiredifferent surface treatments.Extension to other dopants,dopingranges or composition ranges requires further work to relatelPLto the phosphorus content as determined by X-ray mea-surements of the precise dimensions of the unit cell upon whichthe calibration data are based.It is essential that calibrationspecimens have uniform composition in the volume sampled.1.5 This test method is essentially nondestructive.It re-quires a light etching of the sample to be measured.Theremoval of a layer of material approximately 0.5 to 1.0 m inthickness is required.This etching does not degrade thespecimen in that devices can still be fabricated from it.1.6 This test method is applicable to process control in thepreparation of materials and to materials acceptance.1.7 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 safety and health practices and determine the applica-bility of regulatory limitations prior to use.Specific hazardstatements are given in Section 7.2.Referenced Documents2.1 ASTM Standards:D 1125 Test Methods for Electrical Conductivity and Re-sistivity of Water2E 177 Practice for Use of the Terms Precision and Bias inASTM Test Methods3E 275 Practice for Describing and Measuring Performanceof Ultraviolet,Visible,and Near-Infrared Spectrophotom-eters42.2SEMI Standard:C1 Specifications for Reagents53.Summary of Test Method3.1 The photoluminescence spectrum is recorded for thewavelength range from 600 to 750 nm and the wavelength,lPL,at which maximum luminescence occurs is determined bymeans of a graphical construction.The phosphorus content isthen determined by means of a calibration curve relating lPLtothe amount of phosphorus as determined by X-ray measure-ment of the precise dimension of the unit cell.4.Interferences4.1 The apparent position of the photoluminescence peakcan be distorted by the spectral response characteristics of thedetection system,and,in particular,by the spectral response ofthe photomultiplier.Therefore,the detector to be used formeasurements on a specific range of alloy compositions shouldbe chosen so that the corresponding range of lPLfalls in aregion where the detector response is changing slowly.1This test method is under the jurisdiction of Committee F01on Electronics andis the direct responsibility of Subcommittee F01.15 on Compound Semiconductors.Current edition approved Nov.28,1983.Published July 1984.Originallypublished as F 358 72 T.Last previous edition F 358 73(1983).2Annual Book of ASTM Standards,Vol 11.01.3Annual Book of ASTM Standards,Vol 14.02.4Annual Book of ASTM Standards,Vol 03.06.5Available from Semiconductor Equipment and Materials Institute,625 Ellis St.,Suite 212,Mountain View,CA 94043.1Copyright ASTM International,100 Barr Harbor Drive,PO Box C700,West Conshohocken,PA 19428-2959,United States.4.2 The presence of strong background radiation and,inparticular,of background radiation which changes rapidly withwavelength can displace the apparent position of the photolu-minescence peak.Users should,therefore,assure themselvesthat the background radiation is small by replacing the samplewith a mirror and scanning through the wavelength range ofinterest.The result