ASTM_F_673_-_90_1996e1.pdf

Designation:F 673 90(Reapproved 1996)e1Standard Test Methods forMeasuring Resistivity of Semiconductor Slices or SheetResistance of Semiconductor Films with a NoncontactEddy-Current Gage1This standard is issued under the fixed designation F 673;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 January 1996.INTRODUCTIONThis test method is intended to outline the principles of eddy-current measurements as they relateto semiconductor substrates and certain thin films fabricated on such substrates as well as requirementsfor setting up and calibrating such instruments for use particularly at a buyer-seller interface.Becausesuch eddy-current measurements for semiconductor materials are made almost exclusively withcommercial instrumentation from one of several suppliers,some details included here such as specificrange limits and manner of entering slice/wafer thickness values to obtain resistivity values may notapply strictly to all instruments.In all such cases,the owners manual for the particular instrumentshall be considered to contain the correct information for that instrument.It is to be noted that aneddy-current instrument directly measures conductance of a specimen.Values of sheet resistance andresistivity are calculated from the measured conductance,with the resistivity values also requiring ameasurement of specimen thickness.1.Scope1.1 These test methods cover the nondestructive measure-ment of bulk resistivity of silicon and certain gallium-arsenideslices and of the sheet resistance of thin films of silicon orgallium-arsenide fabricated on a limited range of substrates atthe slice center point using a noncontact eddy-current gage.1.1.1 The measurements are made at room temperaturebetween 18 and 28C.1.2 These test methods are presently limited to single-crystal and polycrystalline silicon and extrinsically conductinggallium-arsenide bulk specimens or to thin films of silicon orgallium-arsenide fabricated on relatively high resistivity sub-strates but in principle can be extended to cover other semi-conductor materials.1.2.1 The bulk silicon or gallium-arsenide specimens maybe single crystal or poly crystal and of either conductivity type(p or n)in the form of slices(round or other shape)that are freeof diffusions or other conducting layers that are fabricatedthereon,that are free of cracks,voids or other structuraldiscontinuities,and that have(1)an edge-to-edge dimension,measured through the slice centerpoint,not less than 25 mm(1.00 in.);(2)thickness in the range 0.1 to 1.0 mm(0.004 to0.030 in.),inclusive,and(3)resistivity in the range 0.001 to200 Vcm,inclusive.Not all combinations of thickness andresistivity may be measurable.The instrument will fundamen-tally be limited to a fixed sheet resistance range such as givenin 1.2.2;see also 9.3.1.2.2 The thin films of silicon or gallium-arsenide may befabricated by diffusion,epitaxial or ion implant processes.Thesheet resistance of the layer should be in the nominal rangefrom 2 to 3000 V per square.The substrate on which the thinfilm is fabricated should have a minimum edge to edgedimension of 25 mm,measured through the centerpoint and aneffective sheet resistance at least 1000 3 that of the thin film.The effective sheet resistance of a bulk substrate is its bulkresistivity(in Vcm)divided by its thickness in cm.1.2.3 Measurements are not affected by specimen surfacefinish.1.3 These test methods require the use of resistivity stan-dards to calibrate the apparatus(see 7.1),and a set of referencespecimens for qualifying the apparatus(see 7.1.2).1.4 The values stated in SI units are to be regarded as thestandard.The values given in parentheses are for informationonly.1.5 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.1This test method is under the jurisdiction of ASTM Committee F-1 onElectronics and is the direct responsibility of Subcommittee F01.06 on Electricaland Optical Measurement.Current edition approved April 27,1990.Published June 1990.Originallypublished as F673 80.Last previous edition F673 89.1AMERICAN SOCIETY FOR TESTING AND MATERIALS100 Barr Harbor Dr.,West Conshohocken,PA 19428Reprinted from the Annual Book of ASTM Standards.Copyright ASTM2.Referenced Documents2.1 ASTM Standards:E 1 Specification for ASTM Thermometers2F 81 Test Method for Measuring Radial Resistivity Varia-tion on Silicon Slices3F 84 Test Method for Measuring Resistivity of SiliconSlices with an In-Line Four-Point Probe3F 374 Test Method for Sheet Resistance of Silicon Epi-t