ASTM_F_1366_-_92__1997e1.pdf

Designation:F 1366 92(l997)e1Standard Test Method forMeasuring Oxygen Concentration in Heavily Doped SiliconSubstrates by Secondary Ion Mass Spectrometry1This standard is issued under the fixed designation F 1366;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.e1NOTEKeywords were added editorially in April l998.1.Scope1.1 This test method covers the determination of totaloxygen concentration in the bulk of single crystal siliconsubstrates using secondary ion mass spectrometry(SIMS).1.2 This test method can be used for silicon in which thedopant concentrations are less than 0.2%(1 3 1020atoms/cm3)for boron,antimony,arsenic,and phosphorus(see TestMethod F 723).This test method is especially applicable forsilicon that has resistivity between 0.0012 and 1.0 V-cm forp-type silicon and between 0.008 and 0.2 V-cm for n-typesilicon(see Test Methods F 43).1.3 This test method can be used for silicon in which theoxygen content is greater than the SIMS instrumental oxygenbackground as measured in a float zone silicon sample,but thetest method has a useful precision especially when the oxygencontent is much greater(approximately 103 to 203)than themeasured oxygen background in the float zone silicon.1.4 This test method is complementary to infrared absorp-tion spectroscopy that can be used for the measurement ofinterstitial oxygen in silicon that has resistivity greater than 1.0V-cm for p-type silicon and greater than 0.1 V-cm for n-typesilicon(see Test Method F 1188).The infrared absorptionmeasurement can be extended to between 0.02 and 0.1 V-cmfor n-type silicon with minor changes in the measurementprocedure.21.5 In principle,different sample surfaces can be used,butthe precision estimate was taken from data on chemical-mechanical polished surfaces.1.6 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.2.Referenced Documents2.1 ASTM Standards:E 122 Practice for Choice of Sample Size to Estimate aMeasure of Quality for a Lot or Process3F 43 Test Methods for Resistivity of Semiconductor Mate-rials4F 723 Practice for Conversion Between Resistivity andDopant Density for Arsenic-Doped,Boron-Doped,andPhosphorus-Doped Silicon4F 1188 Test Method for Interstitial Atomic Oxygen Contentof Silicon by Infrared Absorption43.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 ion mass spectrometrythe separation and countingof ions by their mass-to-charge ratio.3.1.2 primary ionsions created and focussed by an iongun onto the specimen surface to sputter ionize surface atoms.3.1.3 secondary ionsions that leave the specimen surfaceas a result of the primary ion beam sputter ionizing thespecimen surface atoms.3.1.4 secondary ion mass spectrometrymass spectrometryperformed upon secondary ions from the specimen surface.4.Summary of Test Method4.1 SIMS is utilized to determine the bulk concentration ofoxygen in single crystal silicon substrate.Specimens of singlecrystal silicon(one float-zone silicon specimen,two calibrationspecimens,and the test specimen)are loaded into a sampleholder.The holder with the specimens is baked at 100C in airfor 1 h and then transferred into the analysis chamber of theSIMS instrument.A cesium primary ion beam is used tobombard each specimen.The negative secondary ions are massanalyzed.The specimens are presputtered sequentially toreduce the instrumental oxygen background.The specimensare then analyzed,in locations different from the presputteringlocations,for oxygen and silicon in a sequential mannerthroughout the holder.Three measurement passes are madethrough the holder.The ratio of the measured oxygen andsilicon secondary ion intensities(O/Si)is calculated for eachspecimen.The relative standard deviation(RSD)of the ratio is1This test method is under the jurisdiction of ASTM Committee F-01 onElectronics and is the direct responsibility of Subcommittee F01.06 on SiliconMaterials and Process Control.Current edition approved Jan.15,1992.Published March 1992.2Hill,D.E.,“Determination of Interstitial Oxygen Concentration in Low-Resistivity n-type Silicon Wafers by InfraredAbsorption Measurements,”Journal ofthe Electrochemical Society,Vol 137,1990,p.3926.3Annual Book of ASTM Standards,Vol 14.02.4Annual Book of ASTM Standards,Vol 10.05.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTMthen calculated for each specimen.If any specimen other thanthe float zone specimen has a RSD of the ratio greater than3%,more analyses are performed.Th