ASTM_F_397_-_93_1999.pdf

Designation:F 397 93(Reapproved 1999)DIN 50430Standard Test Method forResistivity of Silicon Bars Using a Two-Point Probe1This standard is issued under the fixed designation F 397;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 method2covers the measurement of the resis-tivity of single-crystal bars having cross sections that areuniform in area and square,rectangular or round in shape,andhaving resistivity between 0.0009 and 3000 Vcm.The resis-tivity of a silicon crystal is an important acceptance require-ment.1.2 This test method is intended for use on single crystals ofsilicon of either n-or p-type for which the uniformity of thecrystal cross section is such that the area can be accuratelycalculated.The specimen cross-sectional area shall be constantto within 61%of the average area as determined by measure-ments along the crystal axis(see 12.2).1.3 The ratio of the length to the maximum dimension of thecross section of the specimen shall not be less than 3:1(see12.1).The largest diameter tested by round robin was 3.75 cm(1.5 in.),and this is the largest diameter that can be measuredby this method.The specimen shall normally have a surfacefinish of 0.4 m(16 in.)rms or less(see ANSI B46).Othersurface finishes may be used if mutually acceptable;however,the multilaboratory precision figures of this test(see 16.1)thenmay no longer apply.1.4 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 9.2.Referenced Documents2.1 ASTM Standards:D 1193 Specification for Reagent Water3E 1 Specification for ASTM Thermometers4F 42 Test Methods for Conductivity Type of ExtrinsicSemiconducting Materials52.2Other Standard:ANSI B46 Surface Texture62.3SEMI Standard:C1Specifications for Reagents73.Terminology3.1 Definitions of Terms Specific to This Standard:3.1.1 resistivity,rVcmof a semiconductor,the ratio ofthe potential gradient(electric field)parallel with the current tothe current density.4.Summary of Test Method4.1 A direct current is passed through ohmic contacts at theends of a bar specimen and the potential difference is deter-mined between two probes placed along the current direction(see 7.3.1).The resistivity is calculated from the current andpotential values and factors appropriate to the geometry.Thistest method includes procedures for checking both the probeassembly and the electrical measuring apparatus.4.1.1 The spacing between the two probe tips is determinedfrom measurements of indentations made on a polished single-crystal surface.4.1.2 The accuracy of the electrical measuring equipment istested by means of an analog circuit containing a knownresistance together with other resistors which simulate theresistance at the contacts between the probe tips and thesemiconductor surface.4.2 Procedures for preparing the specimen,for measuringits size,and for determining the temperature of the specimenduring measurement are also given.A table of temperaturecoefficient of resistivity versus resistivity is included with themethod so that appropriate calculations can be made.5.Significance and Use5.1 This test method is recommended for material accep-tance and manufacturing control of single-crystal bulk silicon.It is also applicable to other semiconductor materials butneither the appropriate conditions of measurement nor theexpected precision have been experimentally determined.1This test method is under the jurisdiction of ASTM Committee F-1 onElectronicsand is the direct responsibility of Subcommittee F01.06 on SiliconMaterials and Process Control.Current edition approved Aug.15,1993.Published October 1993.Originallypublished as F 397 74 T.Last previous edition F 397 88.2DIN 50430 is an equivalent method.It is the responsibility of DIN CommitteeNMP 221,with which Committee F-1 maintains close technical liaison.DIN 50430,Testing Inorganic Semiconductor Materials:Measurement of the Specific ElectricalResistance of Bar-Shaped Monocrystals of Silicon or Germanium by the Two-ProbeDirect Current Method is available from Beuth Verlag GmbH,Burggrafenstrasse4-10,D-1000 Berlin 30,Federal Republic of Germany.3Annual Book of ASTM Standards,Vol 11.01.4Annual Book of ASTM Standards,Vol 14.03.5Annual Book of ASTM Standards,Vol 10.05.6Available from American National Standards Institute,11 West 42nd St.,13thFloor,New York,NY 10036.7Available from the Semiconductor Equipment and Materials International,805E.Middlefield Rd.,Mountain View,CA 94043.1Copyright ASTM,100 Barr Harbor Drive,West Conshohocken,PA 1942