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(114) Price, C., Forget, J., Booth, C., Polymer, 18, 526-7 (1977). (115) Quinn, H. M., J . Chromatogr. Sci., 15, 424-33 (1977). (116) Rahlwes, D., Roovers, J. E., Bywater, S., Macromolecules, 10, 604-9 (1977). (117) Rapoport, E. L., Lopatina, I. V.. Shmeleva, L. Y., Konoshchenok, T. V., Int. Polym. Sci. Tecbnol., 4(8), T91-2 (1977). (118) Rappaport, S. M., Fraser, D. M., Am. Ind. Hyg. Assoc. J., 38, 205-10 (1977). (119) Sanchez, I . C., J . Polym. Sci., Polym. Symp., 59, 109-20 (1977). (120) Scholte, T. G., Meijerink, N. L. J.. Br. Polym. J., 9(2), 133-9 (1977); Chem. Abstr., 8 8 , 51254 (1978). (121) Shagov, V. S., Stepanova. N. N.. Yakubchik, A. I., Vestn. Leningr. Univ., f i z . , Khim.. 1976(3), 148-51; Chem. Abstr., 85, 1 9 3 8 7 3 ~(1976). (122) Shapiro. Y. E., Dozorova, N. P., Turov, B. S., Shuetsov, 0. K., Zh. Anal. Khim., 3 3 , 393-6 (1978); Chem. Abstr., 8 8 , 137660b (1978). (123) Sheth, P. J., Johnson, J. F., Porter, R. S., Polymer, 18,741-2 (1977). (124) Shibata, C., Yamazaki, M.. Takeuchi, T., Bull. Chem. SOC. Jpn.. 5 0 , 311-2 (1977). (125) Shimada, S., Japanese Patent 76 147389, Dec. 17, 1976; Chem. Abstr., 86, 1227219 (1977). (126) Simha, R., Ann. N . Y . Acad. Sci., 279, 2-14 (1976). (127) Sircar. A. K.. Lamond, T. G., Rubber Chem. Technol., 51, 647-54 (1978). (128) Smith, R. W., Folt, V. L.. ibld.. 5 0 , 835-41 (1977). (129) Spitz, J. J., Laurence, R. L., Chappelear, D. C., AIChE Symp. Ser., 72 (160), 86-101 (1976); Chem. Abstr., 86, 172122h (1977). (130) Srnensky, J., Swiss Patent 583421, Dec. 31, 1976; Chem. Abstr., 86, 73366) (1977). (131) Stacy, C. J., Kraus, G., Polym. Eng. Sci., 17, 627-33 (1977). (132) Strazielle. C., Czionkowska-Kohutnicka, Z . , J . Appl. Polym. Sci., 2 2 , 1135-42 (1978).
(133) Su, T. K., Mark, J. E., Rubber Chem. Techno/., 51, 285-96 (1978). (134) Tanaka, T., Kotaka, T.. Ban, K.. Hattori, M.. Inaaaki. H.. Macromolecules. IO, 960-7 (1977) (135) Tanaka, Y., Sato, H., Polymer, 17, 113-6 (1976) (136) Ibid., pp 413-8. (137) Tanaka, Y., Sato, H., Hatada, K., Terawaki, Y., Okuda, H., Rubber Chem. Technol., 51, 168-79 (1978). (138) Tidd, B. K., Plast. Rubber: Mater. Appl., 2 , 100-6 (1977). (139) Tsuge, K., Hashimoto, K. M., Int. Polym. Sci. Technol., 3(11), T71-4 ( 1976). (140) Tung, L. H., Moore, J. C., fractionation Synth. Polym., 545-647 (1977). (141) Tuzar. Z . , Sikova, A,, Petrus, V., Kratochvil, P., Makromol. Chem., 178, 2743-6 (1977). (142) Ural'skii, M. L.. Makarova, S. A., Gorelik, R. A., Tikhonov, G. P., Bukanov, A. M., I n t . Polym. Sci. Technol. 4(4), T107-9 (1977). (143) Urbanski, J., Czerwinski, W., Janicka, K., Majewska, F., Zowall, H., Handbook of Analysis of Synthetic Polymers and Plastics", Halstec Press, New York, 1977. (144) Vanderhoff, B. M. E., Gall, C. E., J . Macromol. Scl. Chem., 9, 1739-58 (1977). (145) Vaughn, M. F., Francis, M. A,, J . Appl. Polym. Sci., 21,2409-18 (1977). (146) Vinogradov, G. V., Polymer, 18, 1275-85 (1977). (147) Vozka, S., Kubin, M., J . Chromatogr., 139, 225-35 (1977). (148) Wadelin, C . W., Morris, M. C., Anal. Chem., 49, 133R-9R (1977). (149) Wancheck, P. L., Wolfram, L. E., Appl. Spectrosc., 30, 542-4 (1976). (150) Waters Associates, Maple Street, Milford, Mass. 01757. (151) Williams, R. L., Cadie, S. H.. Rubber Chem. Techno/.,51, 7-25 (1978). (152) Yeager, F. W., Becker, J. W., Anal. Chem., 49, 722-4 (1977). (153) Yan, W. W., Stoklosa, H. J., Bly, D. D., J. Appl. Polym. Sci., 21, 1911-20 (1977).
Surface Characterization Philip F. Kane" and Graydon B. Larrabee Materials Characterization Laboratory, Texas Instruments Incorporated, Dallas, Texas 75265
This Applications Review follows the format established in the first of this particular series (217) published in 1977. T h e references are limited t o English-language journals or easily available translations and the surface is defined as the gas-solid interface. T h e format, as before, sorts the information into the substrates on which the surfaces form. Again, we have made extensive use of abbreviations for the techniques employed. Most of these are well-known and are given in Table I. During 1977, a new journal (323)appeared, Applications of Surface Science, which will publish papers in the field covered by this review, i.e., the application of characterization t o the solution of problems involving surface studies, such as corrosion and catalysis. This is expected to be a prime source for future reviews.
METALS Metal surfaces have received considerable attention and again during this review period account for over half of the total references. While this is probably due in part to the fact that metals are excellent subjects for the most commonly used characterization techniques, it also reflects their importance buth as engineering materials and as catalysts. In both areas, surface reactions with gases are highly significant. An excellent review covering the application of surface characterization techniques to chemisorption and catalysis on metals has recently been published (134). A!.kali Metals. The reaction of oxygen with potassium films was determined by a gravimetric method (220). Light Metals. T h e absorption of oxygen on evaporated magnesium was studied by AES, XPS, and UPS (148) and on polycrystalline magnesium and aluminum films by synchroton source X P S (310). Oxidation of evaporated alumiunum films was followed by AES (227)and by gravimetry and A$ (32).;studies on a 1% Mg alloy using AES and MS showed formation of MgO on the surface to increase the electron multiplication 10- to 15-fold (171). Oxide formation in air on 0003-2700/79/035 1-308R$O 1.0010
Table I. Abbreviations Auger Electron Spectroscopy Appearance Potential Spectroscopy Change in Work Function 40 Ellipsometry ELL EELS Electron Energy Loss Spectroscopy EMP Electron Microprobe Analysis Electron Paramagnetic Resonance EP R Electron Stimulated Desorption ES D Electron Spin Resonance ESR FEM Field Emission Microscopy FIM Field Ion Microscopy IMMA Ion Microprobe Mass Analysis Ion Scattering Spectroscopy ISS LEED Low Energy Electron Diffraction Mass Spectroscopy MS Nuclear Magnetic Resonance NMR Rutherford Backscattering RBS RHEED Rpflection High-Energy Electron Diffraction SAM Scanning Auger Microscopy Scanning Electron Microscopy SEM Secondary Ion Mass Spectroscopy SIMS Thermal Desorption TD TEM Transmission Electron Microscopy UHV Ultra High Vacuum UV Photoelectron Spectroscopy UPS X-ray Photoelectron Spectroscopy (ESCA) XPS X-ray Diffraction XRD X-rav Fluorescence XRF AES APS
single crystal aluminum was examined by XPS, AES, A$, ELL and surface plasma spectroscopy (51) and by IR reflectance (288);oxidation by water and oxygen was compared using XPS (127). The composition of the passivation films on aluminum formed in chromate solution was shown by X P S (232)to be a mixture of hydrated chromium and aluminum oxides. The 1979 American Chemical Society
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Phllllp F. Kane's long career with chemical analysis began in 1938 at the quality control labmatones of Standard Telephones and Cables Ltd., London While there he studied part time at London University and was graduated in 1948. The following year he joined Laporte Chemicals Ltd., Luton, England, where he developed methods for trace determinations in hydrogen peroxide and organic peroxides I n 1957 he joined the Chemagro Corp in Kansas City, Mo., to direct a group developing methods for the analysis of organophosphorus pesticdes Since 1959 he has been wrth Texas Instruments in Dallas and has concentrated his research efforts in the characterization of semiconductor matenals. He is currently drector of their Mater& Charactenzakm CWMIS~Y, Laboratmy. Mr. Kane has published a number of articles in ANALYTICAL Journal of Agrcuffurai ami F& ChemLstry, and Chemical Technology. &-author of the book ' Characterization of Semiconductor Materials and co-edrtor of the book, 'Characterization of Solid Surfaces ', he is also a contributor to ' Standard Methods of Chemical Analysis' and Annual Reviews of Materials Science Mr Kane is a member of the Society for Applied Spectroscopy (National Presdent-Elect) and the Chemical Society (London) and a Fellow of the Royal Instttute of Chemistry He is currently serving on ~e Advisory Boara of ANALYTICAL CHEMISTRY Gravdon B. Larrabee has received his M.Sc. in Chemistry. McMaster University. Hamilton, Ontario, Canada, and B Sc in Chemistry, University of Bishop's College, Lennoxville, Quebec, Canada He is author of articles published in The Analyst(London), ANALYTICAL CHEMISTRY, Journal of the Nectrochemcai Socety, and Zertsehrfi iir Analytiscke Cheme, "Surface Contaminaton ' in Preparation of the 111-V Compounds , Reinhold Publishing Co , New York, 1962, co-author with P F Kane on the characterization of Semiconductor Materials , McGraw-Hill, New York, 1970, co-editor with P F Kane on The Characterization of Solid Surfaces ', Plenum Press, # :A . New York, 1974, and co-author with P F Kane, ' Trace Analysis Techniques for Solids , in 'Annual Reviews of Materials Science ', Annual Reviews, 1974 Mr Larrabee is Manager of the Characterization Branch in the Materials Characterization Laboratory of Texas Instruments He joined Texas Instruments in 1959 as a radiochemist, engaged in the application of radioactive tracer techniques to diffusion, crystal growth, etching, and surface studies of semiconductors Current work in this branch is directed toward developing advanced techniques for the characterizattonof electronic materials including ion microprobe analysis, Auger spectroscopy, X-ray topography, and optical spectroscopy The development of minicomputer automated techniques is an integral part of this program Mr Larrabee has worked extensively on silicon and GaAs transistor process development, silicon integrated circufi and tantalum electrotytic capacttors From 1954 to 1956, he was employed at the Canadian Atomic Energy Establishment at Chalk River. Ontario, where he carried out extensive work on the trans-uranium elements fission product analysis and the use of tracers in anatytical studles As an anawcal chemist at Canadlan Westinghouse, he worked in the fields of ukravokt, visible, and infrared spectroscopy, vacuum fuson anabsis for gases in metals, and emission spectroscopy He is a member of Electrochemical Society, Society for Applied Spectroscopy (North Texas Section President), and Dallas Society of Analytical Chemists
thickness of the native oxide on aluminum was determined by resonant a scattering (309). T h e adsorption of CO on aluminum was examined by AES (368) and of propane by S I M S (105). Monolayers of lead and tin on single-crystal aluminum, alone and in binary mixtures, were investigated by LEED and AES (11). The surface of 2024 aluminum alloy was characterized by AES (381). H 2 and CO absorption on polycrystalline titanium was determined by T D M S (353). The absorption of oxygen, CO and CO, on titanium was studied by SIMS (33,106) and also by AES and X P S (33),of CO by LEED (363) and gravimetrically (219) and of oxygen, CO, and nitrogen by changes in t h e secondary electron yield spectrum (151). T h e oxides formed electrolytically on thin titanium film electrodes were characterized by AES and X P S (12). Additional information on CO reactions with titanium was obtained using A@ (382) and AES (200). Diffusion of sulfur, carbon, and chlorine into powdered a-titanium was followed by AES (262). Copper. L E E D analysis of the copper(ll0) surface indicated the outer layer contracted by about 1070 (307). Argon ion bombardment of both single and polycrystalline metal produced pyramids on the surface as seen by SAM (425).
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T h e oxygen layer adsorbed on single crystal copper was examined by LEED and AES (286) and by EELS, AES, and secondary electron emission (30). Both oxygen and H,S exposures were followed on copper(ll0) by LEED and AES (308). Oxide thicknesses on electrolyte copper films used in printed circuit boards were determined coulometrically (228) and oxide films on evaporated copper characterized by IR spectroscopy (44). A study of the atmospheric corrosion of copper by AES and coulometry showed oxygen, chlorine, and sulfur to be the major contaminants (358). A similar study in solution (167) showed the addition of palladium up to 30% to greatly reduce corrosion. AES has shown (254)that during plasma anodization, oxides of both Cu and the cathode material (Ta, Nb, Al, C) form on the surface. Carbon monoxide adsorption of polycrystalline copper was determined by SIMS (19) and by UPS and X P S (313). On various single-crystal surfaces, CO adsorption has been studied by AES, LEED, EELS, 14,and TDMS (223) and by LEED, 14,and IR spectroscopy (202). A study of the stay time for Xe on polycrystalline copper was carried out using a pulsed molecular beam (428). The reactions of chlorine with a C u ( l l 1 ) surface were studied by AES, LEED, A 4 , and T D (168) and of various phosphorus compounds on C u ( l l 0 ) (138). T h e segregation of Sn on (111)and (110) surfaces was measured by AES and LEED (131) and these same techniques were applied to the deposition of P b and Bi vapors on the (100) face (10). T h e oxidation of ethanol on C u ( l l 0 ) was determined by T D M S (407). Several studies have been made of the surface composition of Cu-Ni alloys using AES (175,231,237,414),AES and UPS (260),and ISS (57). AES was used to identify impurities in the protective oxide films obtained on Cu-Ni by etching or anodizing (283). The adsorption of CO on Cu-Ni (and on the individual metals) was examined by SIMS, A@, TD, and MS (31). The surface composition and structure of Cu-Au alloy were determined by LEED and AES (150). The surfaces of Cu-Au (27) and Cu-Pt (57) were analyzed by ISS. Chromium. The oxide structure of chromium was studied by AES, XPS, and SIMS (92) and by a combined XPS, AES, and SIMS technique (91). The interaction of the C r ( l l 1 ) surface with oxygen was determined by X P S , UPS, and A 4 (159). T h e behavior of the oxide layers on a number of Cr alloys in varying environments was followed by X P S (378). Iron, Cobalt, and Nickel. Oxide films on iron, cobalt, and nickel have been examined by resonant a-scattering (309)and on finely divided iron by Mossbauer spectroscopy and XRD (185). The reaction of oxygen with iron films was studied by X P S and U P S (58) and of oxygen and water by X P S (164). Iron oxidized a t 250 "C in air was examined by Raman spectroscopy (390). Combined XPS, AES, and SIMS were conducted on oxidized high purity iron foil (91). Carbon monoxide adsorption on polycrystalline iron was determined by resistance changes, A@, and T D (416) and by using SIMS on both iron and nickel (19);its coadsorption with hydrogen was also studied by resistance, A@, and T D (415). The adsorption of CO, C 0 2 , C2H2,C,H,, H P ,and NH, on single crystal iron surfaces was monitored by LEED and T D (441). A calorimetric method was used to measure heat of adsorption of H, on polycrystalline iron (417 ) and its adsorption on single crystal surfaces examined by LEED, A@, and U P S (47). Nitrogen and NH3 adsorption on polycrystalline iron have been followed by X P S and UPS (225). Sulfur and carbon diffusion into a-iron was determined bv AES (384). The surface structure of a 1% Si-Fe crystal was analyzed by AES and LEED (405). Steel surfaces have been extensively studied. Weathered steel was characterized by SEM ( 5 )and a stainless steel surface analyzed by AES and Auger APS (224)and by ISS (27). The cleaning of a stainless steel by Ar discharge was followed by pressure changes (65)and the secondary ion and photon yield from Ar+ ion bombardment used to determine the surface composition (270). The surface of a stainless steel exposed to liquid Na was analyzed by E M P and IMMA (406)and two studies used AES to characterize passive films formed on ferritic stainless steels (28,439). AES was also applied in the preparation of stainless steel surfaces for deuterium-tritium storage ( 4 5 ) . Atom probe FIM revealed the segregation of Cr atoms on the surface of Stainless 410 (304).
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In some other ferrous alloys, oxide formation on an Fe -Ni-Cr alloy was examined by AES, XPS, and SIMS (92) and on an Fe-Pd film by AES and XPS (250). Distribution of oxygen on the surface of steels was determined by IMMA (366) and the distribution of nonmetallic inclusions by SEM (431). T h e oxidation of cobalt was investigated using AES, XPS, and SIMS (33, 91). T h e chemisorption of CO on Co(OOO1) and polycrystalline metal was studied by AES, LEED, and T D (52),and on the Co(lO12) surface by AES, LEED, Ad, and T D (332). The adsorption and decomposition of CO on cobalt was demonstrated by AES and X P S (200). Self-diffusion on a Ni(l1O) crystal was studied by LEED (46). Preparation of the surface of nickel for electroplating was followed by ELL, AES, XPS, surface potential, and contact angle (372). Several studies of oxygen interaction with single crystal nickel have been published using X P S (312), RHEED (291),LEED and T D (2411, AES and SIMS ( 3 4 0 ) , XPS, LEED, and SIMS (145);clean and contaminated (with 0 and S)surfaces of Ni(ll0) were compared by ISS (399). The sticking coefficient of hydrogen on a sulfur and oxygen contaminated polycrystalline nickel was determined by AES and LEED (339). The oxide formed on high purity nickel foil was characterized by X P S , AES, and SIMS (91). The corrosion of nickel in air was examined by AES (240, 358) and of permalloy by AES and X P S (249). Oxidation of Inconel was determined by X P S (285) and AES (284). T h e adsorption of CO on single crystal nickel was studied by AES, LEED, and T D (133),LEED ( 7 ) ,EELS (39),and ISS (188);an investigation of nickel and Cu-Ni alloy surfaces was carried out with SIMS, A@, and T D (31). Stay times on polycrysta!line nickel were determined for Xe, Kr, and C 0 2 using a pulsed molecular beam (428). Segregation of sulfur in the Ni(OO1) surface was found by ISS (56) and an X P S analysis of ion-bombarded nickel sheet determined the surface composition (190). Clean and sulfur-saturated crystalline surfaces were examined by X P S (305) and the desorption of adsorbed sulfur from polycrystalline metal was followed by AES (432). Dissolution of carbon through the Ni(ll0) surface was studied by AES and LEED (348)and chlorine adsorption 011 N i ( l l 1 ) hy AES, LEED, A$, and T D (132). Several papers dealt with reactions of organics a t nickel surfaces. Acetylene on Ni(ll1) was examined by EELS (112) and by UPS, LEED, and T D (110), ethylene and acetylene on Ni(1OO) by UPS (201),ethylene on N i ( l l 1 ) by CPS and T D (111).ethylene on Ni(l1O) by AES and MS (444) and on nickel sheet by autoradiography (239). Formic acid interactions with the nickel surface were investigated by AES, LEED, and T D (213)and by AES, SIMS, and T D (294). The adsomtion of sulfur-containing alkanes was studied bv X P S and T D (24) and that of benzene on single crystal niikel by LEED and EELS (38). Refractory Metals. The absorption of CO on both niobium and tantalum was studied by AES (200)and of CO and C 0 2 on tantalum (29) by a combined FEM-MS technique. AES showed that anodes of tantalum and niobium formed oxides of the electrode material and of the cathode material (Ta, Nb, AI, C) during plasma anodization ( 2 5 4 ) . The oxidation of molybdenum was investigated by AES, SIMS, and X P S (33, 91). T h e adsorption of CO on single crystal molybdenum was studied by TD, ESD, A$, LEED, and AES (137)and by AES and LEED (162,163). CO adsorption on polycrystalline Mo was investigated by SIMS (107). The growth of silver clusters on Mo(100) was followed by SEM (187). T h e structure of the tungsten(ll0) surface wa5 examined by AES ( 4 3 4 ) . The reaction of oxygen with single crystal tungsten surfaces has been determined by several workers using LEED (82),14 ( 6 3 , ESD, AES, LEED, and ISS (25, 330), LEED, AES, Ad, and T D (130) and ISS (329);adsorption on a polycrystalline surface was examined using ESD (331). A gravimetric technique and Ad measurement were applied to the study of the coadsorptioii of oxygen and CO on single crystal tungsten (412) and AES to that of oxygen and nitrogen (206);AES, LEED, A@>and T D were applied to the coadsorption of oxygen and copper (26). Carbon monoxide adsorption on various single crystal tungsten surfaces was the subject of investigations using AES (205),EELS ( 3 ) ,AES, LEED, and X P S (3771, ISS (188), ESD, T D , and A4 (255);polycrystalline
tungsten was examined by SIMS (19) and AES (200). T h e reaction of tungsten with C 0 2 and D 2 0 was determined with MS (70) and of acetylene on W(100) by AES, EELS, TD, MS, 14,and LEED (334). Barium on single crystal tungsten was studied by LEED, augmented by A$, TD, and surface plasma losses ( 1 7 4 , palladium by FEM and RBS (343),silver by 14 (230),gallium by a molecular beam-MS method (147), and the decomposition of formaldehyde by MS (158). F E M studies involved the adsorption on single crystal tungsten of methane (360), potassium (3561, iron and lead (215), copper (2141, and mercury (216);FIM studies involved halogens 1136) and the deposition of iron (296). LEED, AES, and T D were used to investigate the adsorption of CO on single crystal rhenium (203)and this last technique was also applied to the adsorption of acetylene and ethylene on both single crystal and polycrystalline metal (121) and of the coadsorption of oxygen and N 2 0 with CO (157). Precious Metals. The adsorption and desorption of several gases on single crystal ruthenium have been investigated, including hydrogen (102),nitrogen (102),and ammonia (102, 103) by TD, AES, and LEED; CO by AES, UPS, and X P S (149);hydrogen, CO and formaldehyde by T D and UPS (144);and the coadsorption of CO and oxygen by TD, AES, and LEED (336). Studies of the reaction of nitric oxide with Ru(lO1O) have used F E M (226) and T D (337),with oxygen LEED and AES (319)and with CO LEED, AES and T D (235). Cycloparaffins on single crystal ruthenium have been investigated by LEED, T D , and ESD MS (271). The structure of the clean rhodium(ll1) surface was determined by LEED (74). LEED, AES, and T D were applied (72)to the sludy of hydrogen, oxygen, CO, C 0 2 , nitric oxide, acetylene, ethylene, and carbon chemisorbed on single crystal rhodium. Hydrogen and CO adsorption on evaporated rhodium was investigated by IR spectroscopy and T D (420) and CO on the rhodium(ll0) face by LEED, AES, T D , and surface potential (273). The adsorption of CO on polycrystalline rhodium, palladium, iridium, and platinum was examined by AES (200)and the interaction of nitric oxide and CO with polycrystalline metal has been studied by flash desorption and a titration technique (66). Hydrogen adsorption on thin palladium films was followed by a quantitative technique (60) and by ISS (2). An interesting method for determining hydrogen adsorption on both palladium and platinum used the voltage characteristics of an MOS structure built with a P d or Pt gate (265). Oxygen adsorption on polycrystalline palladium and its effect during the catalysis of CO to C 0 2 was determined by AES (280). The reaction of single crystal palladium surfaces with CO was investigated by LEED and EELS (16), by LEED and IR spectroscopy (50) and, in interaction with oxygen, by I,EED, UPS, and T D (93);on polycrystalline surfaces, it was studied by SIMS (19) and, for both P d and Pt, by IR spectroscopy (298). The interactions of nitric oxide and oxygen on P d ( l l 1 ) were examined by UPS, LEED, and T D (94, 95). lJPS was used to monitor the decomposition of methanol, dimethyl ether, formaldehyde, acetaldehyde, and acetone at the polycrystalline palladium surface (267). The surface of powdered platinum -palladium alloys was reported by AES to be rich in Pd (2.?8),and of gold-palladium alloys to he rich in Au (211). Similar AES studies (352) on silver-palladium alloys showed silver enrichment at the surface although co-segregation with sulfur reduced this; another AES investigation (153)showed untreated alloys to be surface rich in P d and the Ag t G segregate on thermal anneal. No segregation could be detected by AES in a vanadium-palladium alloy (62). The chemisorption of CO on palladium particles evaporated onto mica could be monitored by T D (393). The structure of the iridium(ll0) surface was determined by a LEED study of a '/,-monolayer oxygen film (73). This same surface was reacted with hydrogen, oxygen, nitrogen, ethylene, and benzene and examined by LEED, AES, and TDMS (306);an additional study with CO used TDMS (338). Some adsorbants have been examined on I r ( l l 1 ) ; oxygen by LEED and UPS (96),CO by UPS and X P S (4431, and nitric oxide by LEED, UPS. and T D (218). The oxidation of CO by NO on this surface was determined by XPS and UPS ( 142). CO was also studied on iridium and platinum foil by UPS and X P S (443) and nitric oxide on Ir(100) by UPS, LEED, and T D (218).
ANALYTICAL CHEMISTRY, VOL. 51, NO. 5, APRIL 1979
T h e structure of platinum(ll1) and (100) surfaces was determined by RRS (311). Hydrogen adsorption on single crystal platinum was examined by EELS (209),AES and T D (282),T D (89),and UPS (90);these last two also include work on polycrystalline metal. On P t ( l l l ) ,t h e adsorption of nitrogen was studied by IR spectroscopy (361) and by LEED, AES, and T D (351). T h e reaction of oxygen with single crystal platinum has been investigated using T D (89),UPS (M),AES, LEED, and T D (166, 303, 350, 426). Oxidation of polycrystalline platinum has been characterized by AES (279),T D ( 8 9 ) ,U P S ( g o ) , and, in the presence of CO, by an electrical resistance technique (35). Reactions of CO with single crystal metal have been reported using IR spectroscopy (99,362),T D (89),UPS (M),AES, LEED, T D MS, and A@ (303),AES and T D MS (282),LEED, T D , and A@ ( I % ) , LEED and XPS (551, a n d electron backscattering enhancement (2811, and with polycrystalline metal, using T D (89) and UPS (90). Nitric oxide on Pt(ll1) has been studied using EELS, LEED, and T D (210) and AES, LEED, and T D (165);this latter study also included ammonia. Cyanogen adsorbed on single crystal surfaces was investigated by EELS (427),LEED, AES, and T D MS (53)and AES, LEED, T D MS, and A 4 (303). A study of H2Sadsorption on Pt(100) and the subsequent distribution of sulfur was followed by LEED, A 4 , and X P S (140). Acetylene adsorbed layers on Pt(ll1) were analyzed by L E E D (222) and E E L S (209). Acetylene and ethylene adsorbed species were determined by EELS (208)and acetylene and benzene by AES, LEED, UPS, and T D MS (142),all on single crystal metal. Ethylene reactions with single crystal faces have been observed by UPS (141), EELS (209),and AES, LEED, T D MS, and A@ (303). Ethylene, allylamine, dylacetic acid, chlorotrifluoroethylene, and thiophene were all examined for their reactions with the Pt(100) surface by LEED and AES (347). T h e surface diffusion of carbon on Pt(ll1) could be measured by AES (277) and that of single atoms of platinum, iridium, and gold on various platinum faces demonstrated by FIM (21). No segregation could be detected by FIM in Pt-BYc W and Pt-5% Ru alloys (304) b u t Pt enrichment was found by AES in Pt-Ir (236). Carbon was detected on the (111) surface of carbon doped platinum single crystal by LEED and AES (183) but this was attributed to precipitation. Tungsten-platinum and platinum-platinum mechanical contacts were examined for damage by F I M (411). T h e electrolytic deposition of silver and copper on platinum was observed by AES and X P S (284). T h e surface of polycrystalline silver was characterized by SIMS and X P S (193). Hydrogen adsorption was determined on polycrystalline surfaces by ISS ( 2 ) and its atmospheric corrosion followed by AES and coulometry (358). On single crystal surfaces, oxygen adsorption and the reaction of oxygen with CO were studied by AES and LEED ( 4 ) ;the oxidation of methanol (408) and ethanol (407)were determined by MS. T h e coadsorption of oxygen and chlorine and their reactions were investigated by T D MS and LEED (274);other halogen studies, all on A g ( l l l ) , include chlorine by LEED and AES (398),chlorine (168) and bromine (169) by LEED, AES, T D MS, and A@. This last also included studies on sodium treated Ag(ll1) and similar experiments were performed with nitric oxide ( I 70). The formation of silver sulfide on an evaporated silver film was followed by attenuated total reflection and electron microscopy (233). An AES characterization of the surface of silver--gold alloys indicated slight silver enrichment after annealing and heavy gold enrichment after ion bombardment (438). T h e adsorption of oxygen on polycrystalline gold was determined by AES (128) and of CO by UPS and X P S (313). T h e adsorption of iodide anions from solution was shown by admittance- potential curves to be dependent on the crystal face of a gold electrode (182). AES was applied to the determination of Cr in Cr-Au alloys (197) and to the surface analysis of oxidized Cu-Au and Ni-Au alloys (181). Characterization of the surface of gold-tin alloys by AES indicated tin segregation increasing from 50 at. % up to 86 at. % Au (320). T h e adsorption of lead on various gold single crystal faces was examined by AES and L E E D (40). Other Metals. The oxidation of tin has been investigated by X P S (246) and both tin and indium by X P S and AES (2Ei8). XPS was applied to the determination of the oxidation state of the oxide -hydroxide surface after polarization of tin
311 R
electrodes in sodium hydroxide solution (8). The passive film on electroplated Sn-Ni alloy was characterized by X P S (391) and the native oxide on a Sn-Co alloy by X P S and AES (3%92). T h e reaction of oxygen with evaporated films of calcium, strontium, and barium was studied by APS (314) and the oxidation of polycrystalline lead by SIMS and X P S ( 1 9 4 . XPS analysis of cerium, lanthanum, and yttrium foils showed surface oxides with composition a function of depth (20). Oxygen in the gadolinium surface was determined by resonance a-scattering (309). T h e presence of CO adsorbed on erbium was demonstrated by A@ (382). T h e reactions of oxygen and CO on single crystal thorium were measured by LEED and AES (23) and the diffusion of carbon and oxygen a t the thorium surface was determined by AES (22).
SEMICONDUCTORS Silicon. LEED continues to be the principal tool utilized for studying surface structure and atomic rearrangements on silicon (318, 328, 395, 422). LEED has also been employed to characterize hydrogen chemisorption (9.423,424),cesium adsorption (410),silver deposition (252. 418), and gold deposition (251)on silicon surfaces. AES was used (204) to follow the deposition of Ag on S i ( l l 1 ) . A linear Auger signal with time was observed until the silver surface concentration was 7.6 f 0.9 X l0l4 atoms/cm2, which is in close agreement with the silicon surface state density of 8 to 10 X 10"/cm2. Both AES and transmission electron diffraction were used t o understand the interaction of very thin nickel deposits ol? silicon. Annealing a 15-A film a t 400 "C produces 6-Ni;Si (345). Both Nisi and NisSi polycrystals were observed for a 120-A deposited film. The adsorption of " 2 1 and HBr on Si(ll1) was investigated with AES, EELS, ESD, and 1 4 1 i2.921. The average sticking probability for HCl and HBr was -0.7. The adsorption of CO on polished and oxygen etched S i ( l l 1 ) surfaces was studied using SEM, AES, and ESD (126); C O was found to have a low sticking probability. AES analvsis of oxygen adsorption on silicon showed that oxygen saturation occurred a t 0.3 monolayer without Si02 formation (299). Thicknesses of oxides up to 120 A on silicon (and aluminum) were determined with AES, without ion-mill depth profiling (76)by using the ratio of the chemically shifted and unshifted Auger peaks from the oxide and substrate, respectively. Surface analysis of a silicon target was performed by ion-electron spectroscopy (373). The energy spectrum of secondary electrons emitted due to 6-keV HeC and 02+ ion bombardment was shown to provide a good indication of the degree of coverage of the silicon surface with contaminant ions. SIMS (374,386),neutron activation (325),and RRS (436)were applied to surface analysis of silicon. Mechanical stress at the Si(ll1) surface when covered with S i 0 2 and A1-Si02 was measured (212) using a Michelscjn interferometer; the tension was a function of the oxide thickness. AES was employed to study the effect of phosphorus pileup at the Si-SiOs interface (354). SiOs surface defect centers were studied with AES (355) on electron radiation damaged quartz; the absolute energy level of localized. occupied surface defect states was determined. Dissociation of the S i 0 2 surface under electron beam irradiation \vas followed using AES (71). Silanol groups on various silicon oxide materials were measured using free radical spin labels (409). Low coverages of vacuum deposited palladium on amorphous silica substrates were examined using X P S and SEM (385). Silicon nitride films have been analyzed using X P S (49) and combined AES-XPS (335);S P S data showed that there was no measurable elemental silicon (i.e., 5 3 % ) in the film. AES analysis of Si,N+ (394)yielded a composition of Sij8Nl2- a significant deviation. This deviation was due to preferential sputtering during the analvsis and not inherent nonstoichiometry of the chemical vapor deposited film. AES was used to characterize the transition-metal/Si and silicide/ Si interfaces of nine different transition metals (342). Oxide layers on silicon carbide crystals were studied using AES and E L L (
