1、Designation: E 1634 02 (Reapproved 2007)Standard Guide forPerforming Sputter Crater Depth Measurements1This standard is issued under the fixed designation E 1634; the number immediately following the designation indicates the year oforiginal adoption or, in the case of revision, the year of last rev
2、ision. 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 guide covers the preferred procedure for acquiringand post-processing of sputter crater depth measurements. Thisguide is
3、 limited to stylus-type surface profilometers equippedwith a stage, stylus, associated scan and sensing electronics,video system for sample and scan alignment, and computerizedsystem.1.2 This standard does not purport to address all of thesafety concerns, if any, associated with its use. It is there
4、sponsibility 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:2E 673 Terminology Relating to Surface AnalysisE 1162 Practice for Reporting Sputter Depth
5、 Profile Data inSecondary Ion Mass Spectrometry (SIMS)3. Terminology3.1 Definitions:3.1.1 Terms used in surface analysis are defined in Termi-nology E 673.4. Significance and Use4.1 Sputter crater depth measurements are performed inorder to determine a sputter rate (depth/time) for each matrixsputte
6、red during a sputter depth profile or similar in-depth typeanalyses. From sputter rate values, a linear depth scale can becalculated and displayed for the sputter depth profile.4.2 Data obtained from surface profilometry are useful inmonitoring instrumental parameters (for example, raster size,shape
7、, and any irregularities in topography of the sputteredcrater) used for depth profiles.5. General Procedure5.1 Upon completing a sputter depth profile, mark the craterfor future identification (one can mark the exterior corner(s) ofa crater with features, for example, lines, holes, etc., producedusi
8、ng an unrastered ion beam). Note the x- and y-position withrespect to the rastered ion beam and sample geometry orsuitable device feature(s).5.2 Place the sample on the profilometer stage surface. Ifsample has an area of less than 1 cm2, mount the sample ontoanother larger flat surface to prevent sa
9、mple movement whenprofilometry is performed. The system should be reasonablyleveled; for details on instrumental adjustments, see manufac-turers operational manual(s). Keep the environment as dust-free as possible and dust-off the sample surface with cleanair/gas jet before performing the measuremen
10、t.5.3 Pre-select surface profilometer operational settings;computerized models are commonly used. Most surface pro-filometers commonly permit selection of the following param-eters:5.3.1 Stylus type (for example, diamond stylus),5.3.2 Stylus radius (for example, 5 m; various stylus radiiare availabl
11、e depending upon desired resolution of measure-ment, and to a certain degree the strength of the stylus tip forvarying hardness of materials),5.3.3 Stylus force (that is, force exerted on the analyticalsample during operation, for example, 15 mg; this is animportant variable when profiling sample wi
12、th high hardnesslevels; damage to the stylus may occur, and hence damage tothe instrumentation or errors in profilometry measurements, orboth, may result),5.3.4 Scan speed (for example, 50 m/s; this value isdependent upon permissible noise levels, accuracy, etc., and istypically determined experimen
13、tally),5.3.5 Scan length (one typically uses twice the crater size toallow for scanning over the level areas about the sputteredcrater, and5.3.6 Number of scans for signal averaging (for example,three repetitive scans averaged to improve the signal-to-noiseratio).5.4 Lower the stylus in an area outs
14、ide the sputtered crater,at a distance from the crater edge of approximately one-half theactual crater size, and in a reasonably smooth area to traversethe entire crater length. The scan path is typically chosen across1This guide is under the jurisdiction of ASTM Committee E42 on SurfaceAnalysis and
15、 is the direct responsibility of Subcommittee E42.06 on SIMS.Current edition approved June 1, 2007. Published June 2007. Originallyapproved in 2002. Last previous edition approved in 2002 as E 1634 02.2For referenced ASTM standards, visit the ASTM website, www.astm.org, orcontact ASTM Customer Servi
16、ce at serviceastm.org. For Annual Book of ASTMStandards volume information, refer to the standards Document Summary page onthe ASTM website.1Copyright ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959, United States.the center of the sputtered crater in one dir
17、ection with arepetitive measurement in the perpendicular direction, notingthe symmetry with respect to the previously marked craterdirections (see 5.1).6. Interpretation of Results6.1 In general, a plot representative of a sputtered crater willresult (see Fig. 1). The data may then need post-process
18、ing,including leveling, rescaling, zeroing of surface depth, averag-ing top and bottom surface(s), etc. In the leveling process, onenormally chooses a cursor position on the top left and right(outer surface of the crater). Upon leveling, rescaling, andzeroing, the full crater shape should be visible
19、 on the graph,with both top surfaces at the same zero point and the bottomsurface of the crater relatively flat. Some systems permit cursorlocation at several points on the top and bottom surfaces of thecrater. The computer would then average and calculate thedifferences to determine an accurate spu
20、tter crater depthmeasurement.7. Modified Procedure for Large-Area Craters7.1 For larger diameter ion beam sputter craters, such as arefrequently used for Auger electron spectroscopy and x-rayphotoelectron spectroscopy, it may be too difficult to define theoriginal surface height and crater depth fro
21、m the profilometerscan. In these cases, sputter crater depths have been success-fully measured by sputtering the specimen thorugh a metalmesh, such as a 3mm TEM grid with 500 m openings, thenusing the stylus profilometer to measure the heights of thereplicated mesh pattern on the sputtered specimen
22、surface (1).An example is shown in Fig. 2.7.2 It is important for an accurate step-height measure of theoriginal surface and the crater depth that the mesh grid bepositioned directly onto the specimen surface, with no gapseparating the two. Additionally, the mesh material must beselected so that spu
23、ttered contamination from the mesh doesnot interfere with signal from the elements of interest in thespecimen material. This sputtered contamination from themesh will also modestly alter the sputter rate of the specimenmaterial, which may be a concern in some experiments.8. Precision and Accuracy8.1
24、 PrecisionThe precision is determined by repeatingmeasurements several times and reporting the standard devia-tion between values.8.2 AccuracyThe accuracy of the measurement can bedetermined by measuring a calibrated depth standard typicallysupplied with commercial surface profilometers, and calcula
25、t-ing a percent difference from the measured value. Bias oftendepends upon stylus limited point size, scan speeds/distances,vibration during measurement(s), condition of apparatus; cali-bration of surface profilometer equipment, etc., and should beconsidered carefully when measuring sputtered crater
26、 depthand reporting subsequent data.9. Keywords9.1 Auger electron spectroscopy; secondary ion mass spec-trometry; stylus profilometry; surface analysis; x-ray photo-electron spectroscopyFIG. 1 A Typical Stylus Profilometer Scan of a Sputtered CraterFIG. 2 (a) Scanning electron photomicrograph showin
27、greplication of mesh grid pattern on a specimen after sputtering.(b) Stylus profilometry scan across replicated grid pattern tomeasure sputtercrater depth. Crater depth is marked by double-headed arrow. From (1).E 1634 02 (2007)2REFERENCES(1) Suzuki, M., Mogi, K., and Ando, H., “Technical Proposal f
28、or mea-surement of Sputtered Depth Using a MeshEspecially for AugerDepth Profiling,” J. Surf. Anal., Vol. 5, 1999, pp. 188 191.ASTM International takes no position respecting the validity of any patent rights asserted in connection with any item mentionedin this standard. Users of this standard are
29、expressly advised that determination of the validity of any such patent rights, and the riskof infringement of such rights, are entirely their own responsibility.This standard is subject to revision at any time by the responsible technical committee and must be reviewed every five years andif not re
30、vised, either reapproved or withdrawn. Your comments are invited either for revision of this standard or for additional standardsand should be addressed to ASTM International Headquarters. Your comments will receive careful consideration at a meeting of theresponsible technical committee, which you
31、may attend. If you feel that your comments have not received a fair hearing you shouldmake your views known to the ASTM Committee on Standards, at the address shown below.This standard is copyrighted by ASTM International, 100 Barr Harbor Drive, PO Box C700, West Conshohocken, PA 19428-2959,United States. Individual reprints (single or multiple copies) of this standard may be obtained by contacting ASTM at the aboveaddress or at 610-832-9585 (phone), 610-832-9555 (fax), or serviceastm.org (e-mail); or through the ASTM website(www.astm.org).E 1634 02 (2007)3
