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3907. Investigation of oxide growth in nickel thin films. (Germany)
Classified abstracts 3900-3907 pump tritium have presented significant design problems not ordinarily encountered in the design of ultra-high vacuum systems. The configuration and piping schematic of the preliminary design vacuum pumping system capable of fulfilling the requirements is discussed. The selection process for the high-vacuum pumps is reviewed and the rationale for the use of turbomolecular pumps, based on projected overall vacuum pumping system reliability, is presented. A computer was used t o predict vacuum system performance. Preliminary computer-generated pumpdown curves are presented for plasma pulsing operations and pumpdowns from atmospheric pressure. B D Abel, J Vac Sci Technol, 15 (2), 1978, 726-733. 33 3900. Turbomolecular pump vacuum system for the Princeton Large Torus. (USA) A turbomolecular pump vacuum system has been designed and installed on the Princeton Large Torus (PLT). Four vertical shaft, oilbearing, 1500 l/s turbomolecular pumps have been interfaced to the 6400 1 PLT vacuum vessel to provide a net pumping speed of 3000 l/s for H2. The particular requirements and problems of tokamak vacuum systems are enumerated. A vacuum control system is described which protects the vacuum vessel from contamination and protects the turbomolecular pumps from damage under a variety of possible failure modes. The performance of the vacuum system is presented in terms of pumping speed measurements and residual gas behaviour. H F Dyila, J Vac Sci Technol, 15 (2), 1978, 734-740. 33 3901. Cryosorption pumping of deuterium by MS-SA at temperatures above 4.2 K for fusion reactor applications. (USA) An excalibur CVR-1106 cryosorption pump was fitted with a special cooling system to permit measurement of deuterium pumping speeds at temperatures between 6 and 20 K. Pumping speeds were found to be a function of feed rate, loading prior to each run, loading during runs and thermal treatment between runs. At feed rates < 3 × 10 -4 torr 1 s - t c m -2, speeds were near 1 I s - ~ cm -2 initially and declined monotonically with loading. At high feed rates, speeds reached a higher maximum ( ~ 3 1 s -~ cm -2) but also generally declined with loading; however, after 50-100 torr 1 had accumulated, the pump underwent a spontaneous transition which effected a return to the original (high) pumping speed. This transition was accompanied by pressure spikes in the test chamber and temperature spikes in the sieve panel. Initial speeds for each consecutive run equaled the final speed for the preceding run if the pump was maintained at operating temperature; however, if it was warmed to 77 K and recooled, a restoration to the maximum speed was observed at the beginning of the next run. P W Fisher and J S Watson, J Vac Sci Technol, 15 (2), 1978, 741-744. 33 3902. Behaviour of sorb-ac wafer pumps in plasma machines. (USA) Vacuum pumps used in machines studying plasma physics are exposed to peculiar operating conditions. Especially the auxiliary pumps, such as cryopumps and getter pumps which are used in close proximity to the discharge or in injectors, can be exposed to very severe conditions. These pumps must exhibit very high pumping speeds and capacities, particularly for hydrogen, and must operate over a wide range of pressures. They must also be safe and reliable in use. Finally, their characteristics should not be influenced by energetic particle bombardment, radiation incidence, sputtered material on the sorbing surface and by the presence of radioactive substances. The behaviour of getter pumps based on the use of non-evaporable getter material and on a modular structure, known as sorb-ac wafer pumps, is reviewed and discussed here. The operating conditions and the behaviour under radiation, particle bombardment, vacuum breakage accidents, etc. of these pumps meet most of the requirements in nuclear fusion machines and make them particularly suitable for this field of application. (Italy). L Rosai et al, J Vac Sci Technol, 15 (2), 1978, 746--750.
dental prostheses or implants. The materials textured include 316 stainless steel, titanium-6% aluminium, 4~o vanadium and cobalt2 0 ~ chromium, 1 5 ~ tungsten. To determine the effect of ion texturing on the ultimate strength and yield strength, stainless steel. and C o - C r - W alloy samples were tensile tested to failure. Three types of samples of both materials were tested. One type was ion textured (the process also heats each sample to 300°C), another type was simply heated to 300°C in an oven and the third type was untreated. Stress-strain diagrams, 0.2%-offset yield strength data, total elongation data and area reduction data will be presented. Fatigue specimens of ion-textured and untextured 316 stainless steel and T i - 6 ~ AI-4% V were tested. Included as an ion-textured sample is a T i - 6 % A I - 4 ~ V sample which was ion machined by means of a Ni screen sputter mask so as to produce an array of 140 × 104 × 60 t~m deep pits. A table is presented that compares the fatigue characteristics of ion-textured and untextured samples. Scanning electron microscopy was used to characterize the ion-textured surfaces. An electronbeam microprobe was used to analyze the cross-sections of the iontextured samples. A J Weigand, J Vac Sci Technol, 15 (2), 1978, 718-724. 35 3904. Mass spectrometric study of plasma etching. (USA) A quadrupole mass spectrometer gives much useful information about plasma etching processes on silicon and its compounds. The present work confirms some of the known or postulated chemistry in the plasma and raises further questions about the understanding of the process. The instrument enables dynamic optimization of process parameters and provides a variety of diagnostic information. In particular, it allows the detection of etching endpoints and thl[eby provides a sensitive technique for controlling the etching p r ~ t s s . The technique appears to substantially reduce or eliminate the'need for calibration. The account discusses endpoints for polycrystalline silicon, silicon dioxide, silicon nitride and some cases involving photoresist. B A Rahy, J Vac Sci Technol, 15 (2), 1978, 205-208. 35 3905. Analysis of the imaging accuracy in reactive ion etching. (USA) In reactive ion etching the factors which have influence on imaging accuracy consist of the swell of the resist mask, the reduction of the mask, and the undercutting. We investigated these factors about polycrystalline Si, AI and Mo films on Si wafer. The undercutting depends on the overetching time and the ion current. In the case of etching poly-Si film, it corresponds with the change of the impedence of CF4 discharge. Also it was made clear by comparing the experimental results with the calculated field model that the size of undercutting depends on not only the radom motion of the ions but the lack of uniformity of the cathode fall caused from the ruggedness of the pattern on the substrate surface. This fact is consistent with the phenomenon that the dimensional change by etching within the substrate depends on the pattern size. (Japan). K Ukai and K Hanazawa, J Vac Sci Technol, 15 (2), 1978, 338-340. 35 3906. Profile control by reactive sputter etching. (USA) Reactive sputter etching in fluorocarbon gases (i.e. CF4, CHF3) not only results in a large increase of the etch rates, but it can also be used for a high fidelity pattern transfer from patterns delineated in positive photoresist into underlaying substrates (i.e. Si, SiO2, Si3N4). Square wave gratings with micron and submicron periodicities and etch depths of up to 3/~m have been etched. A relatively large etch selectivity of SiO2 over Si has been observed (etch rate ratio = 15 : 1). Reactive sputter etching is primarily a chemical process due to highly reactive species produced on the substrate surface by an ion-molecule reaction between ions from the plasma and neutral gas molecules impinging onto the substrate surface. (Switzerland). H W Lehmann and R Widmer, J Vac Sci Technol, 15 (2), 1978, 319-326. 36. V A C U U M I N T R U M E N T A T I O N FOR S U R F A C E STUDIES
35. PROCESSING O F MATERIALS 35 3903. Mechanical properties on ion-beam-textured surgical implant alloys. (USA) An electron-bombardment Hg ion thruster was used as an ion source to texture surfaces of materials used to make orthopedic and/or
36 3907. Investigation of oxide growth in nickel thin films. (Germany) The oxide growth in nickel thin films was studied by means of Auger electron spectroscopy and ion beam etching in the oxide thickness range 0-50 nm. The depth profiles of the oxygen concentration and 189
Classified abstracts 3908-3915 the changes in concentration due to the oxidation were determined. The evaporation of the film, the preparation of oxide layer and the measurement of the composition profiles were carried out as consecutive steps within the same ultra-high vacuum system without interrupting the vacuum. The shape of the depth profiles depends on the duration of the oxidation period and on the oxidation temperature. In the temperature range T = (5504-10) K the averaged oxide thickness can be described by a parabolic rate law. Von K R611 et al, Vakuum-Tech, 27 (4), 1978, 102-105 (in German). 36 3908. Description of a polarized source of He radiation for surface studies. (USA) A polarized radiation source has been designed and built for use in angular-resolved photoelectron spectroscopy on surfaces of single crystals under ultra-high vacuum. The light from a discharge in helium is polarized by a triplereflectionfrom a seriesof gold mirrors, producing a plane-polarized beam of H e I radiation (21.22 eV) with a polarization of 80 ~o. The plane of polarization can be rotated through more than 180 ° without breaking vacuum. Details of the construction of the lamps are given, together with h o w it is integrated into the overall operation of the electron spectrometer. As an illustrationof the lamp's potential, data are shown on the photoemission studies of the (l I0) and (I I I) faces of copper as a function of both the orientation angle of the crystal and the polarization vector. A brief discussion of the future development and possible uses of the lamp is included. T A Carlson et al, Rev scient lnstrum, 49 (6), 1978, 736-740. 36 3909. Determining the angles of incidence in a LEED experiment. (USA) A new method for determining the angles of incidence in a backreflection, post-acceleration, fluorescent display LEED apparatus is presented which uses the angles between the diffraction spots on a photograph of the LEED pattern. Absolute accuracies better than 0 × 1° for both incidence angles should be routinely available. S L Cunningham and W H Weinberg, Rev seient lnstrum, 49 (6), 1978, 752-755. 36 3910. Computer controlled ESCA for nondestructive surface characterization utilizing a TV-type position sensitive detector. (USA) A position sensitive detector system composed of a channel plate, a vidicon TV camera and a computer is utilized for multichannel detection of ESCA spectra. It is demonstrated that the system achieves a marked improvement of measurement speed, SIN ratio and sensitivity. The system also realized an improvement of spatial resolution while retaining energy resolution. (Japan). M Kudo et al, Rev scient Instrum, 49 (6), 1978, 756-759. 36 3911. Electrical properties of lead-zireonate-lead-titanate ferroelectric thin films and their composition analysis by Auger electron spectroscopy. (USA) Lead-zirconate-lead-titanate (PZT) thin films with perovskite and pyrochlore structures were successfully fabricated on several kinds of substrates by rf diode sputtering. Semiquantitative compositional analysis of the deposited thin films were made with Auger electron spectroscopy (AES). The films were deposited from targets consisting of mixed powder oxides. One target had a composition corresponding to 10 m o l ~ PbO-modified PZT 52/48 (Zr to Ti ratio in the PZT, target A), while the other had the composition corresponding to 10 molto PbO-modified PZT 42/58 (target B). The films in the perovskite structure had ferroelectricity, while the films in pyrochlore had none. The perovskite films deposited from target A had a dielectric constant of 751, a remanent polarization of 20.4/~C/cm 2 and a coercive field of 23.3 kV/cm. The films deposited from target B had a dielectric constant of 654, a remanent polarization of 6.37 t~C/cmz and a coercive field of 12.2 kV/cm. The composition of the former film was PZT 60/40 and the latter, PZT 47/53. The difference in the ferroelectric properties is believed to be in the difference in the compositional ratio of Zr/Ti in the film. (Japan). Akira Okada, J appl Phys, 49 (8), 1978, 4495--4499. 36 3912. Observation of phosphorus pile-up at the SiO2-Si interface. (USA) The Si oxidation rate at high temperatures is increased by heavy P 190
doping. Sputter ion-Auger techniques have been used to investigate the oxide thickness and P concentration after 900°C oxidation with an initial P surface concentration of between 2 × l0 is and 3.2 × 102°/ cm a. Phosphorus was found to pile up in the Si-SiO2 interface region. The maximum P concentration near the interface was found to depend on doping and was (at certain P concentrations) an order of magnitude larger than that predicted by redistribution theory. A vacancy-P-complex model is presented to explain the observed behaviour. A correlation between the selective pile-up of P at the interface and the current gain of planar bipolar transistors is reported. J S Johannessen et al, J appl Phys, 49 (8), 1978, 4453--4458. 36 3913. Electron-solid interactions: their nature and consequences. (USA) During the past two decades electron scattering and emission spectroscopies have become utilized almost universally to characterize the properties of solid surfaces. Two major trends have created this situation: the increasing availability of suitable, convenient experimental apparatus, and the recognition and exploitation of those features of electron-solid interactions which render these measurements sensitive to surface properties. Whereas prior Welch Award lectures have dealt with the former trend, the latter is examined herein. Three concepts are central to an understanding of the interaction of 'low-energy', 10 ~ E ~ I0 a eV electrons with the constituents of solids. First, their strong Coulombic interaction with the valence electrons of the solid renders their mean free paths for inelastic collisions of atomic dimensions, i.e. 2 ~ A ~ 20 A. Thus, elastically scattered or emitted electrons in this energy range must have emanated from the uppermost few atomic layers of the solid. Second, the interactions of these electrons with the core electrons are comparable to those with the valence electrons. Therefore, multiple~ elastic scattering as well as rapid energy loss characterizes their scattering and emission. Third, resonant processes associated with electronic states localized at a surface can be as important as inelastic processes in establishing surface sensitivity. Examples of this phenomenon are found in resonant field emission through adsorbates and resonant photoemission associated with the excitation of transitions characteristic of adsorbed complexes. The major portion of this article is devoted to an indication of how exploitations of these three concepts have led to quantitative surface analysis methodologies for metals and. covalent solids. In the case of polymers and molecular solids, however, one further concept is required: the localization of electronic states caused by fluctuations in relaxation energy. These fluctuations lead to localized molecular ion (or exciton) states rather than extended band states. The final portion of this article is devoted to exploring the consequences of this additional concept and how it led to the invention of yet another electron spectroscopy, contact charge exchange spectroscopy, for the examination of molecular ion states in polymers. C B Duke, J Vac Sci Technol, 15 (2), 1978, 157-169. 36 3914. High resolution Auger sputter profiling study of the effect of phosphorus pileup on the Si-SiO2 interface morphology. (USA) We have used Auger electron spectroscopy in conjunction with sputter etching and crater-edge profiling to study the distribution of phosphorus near the Si-SiO2 interface and the effect of the phosphorus distribution on the width of the interface transition region. The samples studied consisted of thermal oxides approximately 1000 A thick grown on Si (111) substrates with initial phosphorus concentrations up to 6×1020 cm -3. Phosphorus pileup at the Si-SiO2 interface was observed with the phosphorus peak (after correcting for electron excape depth effects) on the Si side within 5 A of the interface. The 1 0 - 9 0 ~ width of the Si-SiO2 transition region as measured by the SiLvv transition varies from 25 (low doping limit) to 38 A (bulk doping level of 6 × 1020 cm-3). Results are interpreted in terms of a recently proposed model for the Si-SiO2 interface. S A Schwarz et al, J Vac Sci Technol, 15 (2), 1978, 237-230. 36 3915. Atomic and electronic structure of semiconductor surfaces. (USA) The electronic structure of surfaces, which can be determined by various electron/ion spectroscopies including ultraviolet photoemission spectroscopy (UPS), is dependent on the surface atomic geometry. Thus, it is possible to determine the surface a t o m i c structure via structure-dependent theoretical analyses of these experimental spectra. Because of the complexity of such systems, a simple but accurate theoretical scheme is required. We show that the valence
dental prostheses or implants. The materials textured include 316 stainless steel, titanium-6% aluminium, 4~o vanadium and cobalt2 0 ~ chromium, 1 5 ~ tungsten. To determine the effect of ion texturing on the ultimate strength and yield strength, stainless steel. and C o - C r - W alloy samples were tensile tested to failure. Three types of samples of both materials were tested. One type was ion textured (the process also heats each sample to 300°C), another type was simply heated to 300°C in an oven and the third type was untreated. Stress-strain diagrams, 0.2%-offset yield strength data, total elongation data and area reduction data will be presented. Fatigue specimens of ion-textured and untextured 316 stainless steel and T i - 6 ~ AI-4% V were tested. Included as an ion-textured sample is a T i - 6 % A I - 4 ~ V sample which was ion machined by means of a Ni screen sputter mask so as to produce an array of 140 × 104 × 60 t~m deep pits. A table is presented that compares the fatigue characteristics of ion-textured and untextured samples. Scanning electron microscopy was used to characterize the ion-textured surfaces. An electronbeam microprobe was used to analyze the cross-sections of the iontextured samples. A J Weigand, J Vac Sci Technol, 15 (2), 1978, 718-724. 35 3904. Mass spectrometric study of plasma etching. (USA) A quadrupole mass spectrometer gives much useful information about plasma etching processes on silicon and its compounds. The present work confirms some of the known or postulated chemistry in the plasma and raises further questions about the understanding of the process. The instrument enables dynamic optimization of process parameters and provides a variety of diagnostic information. In particular, it allows the detection of etching endpoints and thl[eby provides a sensitive technique for controlling the etching p r ~ t s s . The technique appears to substantially reduce or eliminate the'need for calibration. The account discusses endpoints for polycrystalline silicon, silicon dioxide, silicon nitride and some cases involving photoresist. B A Rahy, J Vac Sci Technol, 15 (2), 1978, 205-208. 35 3905. Analysis of the imaging accuracy in reactive ion etching. (USA) In reactive ion etching the factors which have influence on imaging accuracy consist of the swell of the resist mask, the reduction of the mask, and the undercutting. We investigated these factors about polycrystalline Si, AI and Mo films on Si wafer. The undercutting depends on the overetching time and the ion current. In the case of etching poly-Si film, it corresponds with the change of the impedence of CF4 discharge. Also it was made clear by comparing the experimental results with the calculated field model that the size of undercutting depends on not only the radom motion of the ions but the lack of uniformity of the cathode fall caused from the ruggedness of the pattern on the substrate surface. This fact is consistent with the phenomenon that the dimensional change by etching within the substrate depends on the pattern size. (Japan). K Ukai and K Hanazawa, J Vac Sci Technol, 15 (2), 1978, 338-340. 35 3906. Profile control by reactive sputter etching. (USA) Reactive sputter etching in fluorocarbon gases (i.e. CF4, CHF3) not only results in a large increase of the etch rates, but it can also be used for a high fidelity pattern transfer from patterns delineated in positive photoresist into underlaying substrates (i.e. Si, SiO2, Si3N4). Square wave gratings with micron and submicron periodicities and etch depths of up to 3/~m have been etched. A relatively large etch selectivity of SiO2 over Si has been observed (etch rate ratio = 15 : 1). Reactive sputter etching is primarily a chemical process due to highly reactive species produced on the substrate surface by an ion-molecule reaction between ions from the plasma and neutral gas molecules impinging onto the substrate surface. (Switzerland). H W Lehmann and R Widmer, J Vac Sci Technol, 15 (2), 1978, 319-326. 36. V A C U U M I N T R U M E N T A T I O N FOR S U R F A C E STUDIES
35. PROCESSING O F MATERIALS 35 3903. Mechanical properties on ion-beam-textured surgical implant alloys. (USA) An electron-bombardment Hg ion thruster was used as an ion source to texture surfaces of materials used to make orthopedic and/or
36 3907. Investigation of oxide growth in nickel thin films. (Germany) The oxide growth in nickel thin films was studied by means of Auger electron spectroscopy and ion beam etching in the oxide thickness range 0-50 nm. The depth profiles of the oxygen concentration and 189
Classified abstracts 3908-3915 the changes in concentration due to the oxidation were determined. The evaporation of the film, the preparation of oxide layer and the measurement of the composition profiles were carried out as consecutive steps within the same ultra-high vacuum system without interrupting the vacuum. The shape of the depth profiles depends on the duration of the oxidation period and on the oxidation temperature. In the temperature range T = (5504-10) K the averaged oxide thickness can be described by a parabolic rate law. Von K R611 et al, Vakuum-Tech, 27 (4), 1978, 102-105 (in German). 36 3908. Description of a polarized source of He radiation for surface studies. (USA) A polarized radiation source has been designed and built for use in angular-resolved photoelectron spectroscopy on surfaces of single crystals under ultra-high vacuum. The light from a discharge in helium is polarized by a triplereflectionfrom a seriesof gold mirrors, producing a plane-polarized beam of H e I radiation (21.22 eV) with a polarization of 80 ~o. The plane of polarization can be rotated through more than 180 ° without breaking vacuum. Details of the construction of the lamps are given, together with h o w it is integrated into the overall operation of the electron spectrometer. As an illustrationof the lamp's potential, data are shown on the photoemission studies of the (l I0) and (I I I) faces of copper as a function of both the orientation angle of the crystal and the polarization vector. A brief discussion of the future development and possible uses of the lamp is included. T A Carlson et al, Rev scient lnstrum, 49 (6), 1978, 736-740. 36 3909. Determining the angles of incidence in a LEED experiment. (USA) A new method for determining the angles of incidence in a backreflection, post-acceleration, fluorescent display LEED apparatus is presented which uses the angles between the diffraction spots on a photograph of the LEED pattern. Absolute accuracies better than 0 × 1° for both incidence angles should be routinely available. S L Cunningham and W H Weinberg, Rev seient lnstrum, 49 (6), 1978, 752-755. 36 3910. Computer controlled ESCA for nondestructive surface characterization utilizing a TV-type position sensitive detector. (USA) A position sensitive detector system composed of a channel plate, a vidicon TV camera and a computer is utilized for multichannel detection of ESCA spectra. It is demonstrated that the system achieves a marked improvement of measurement speed, SIN ratio and sensitivity. The system also realized an improvement of spatial resolution while retaining energy resolution. (Japan). M Kudo et al, Rev scient Instrum, 49 (6), 1978, 756-759. 36 3911. Electrical properties of lead-zireonate-lead-titanate ferroelectric thin films and their composition analysis by Auger electron spectroscopy. (USA) Lead-zirconate-lead-titanate (PZT) thin films with perovskite and pyrochlore structures were successfully fabricated on several kinds of substrates by rf diode sputtering. Semiquantitative compositional analysis of the deposited thin films were made with Auger electron spectroscopy (AES). The films were deposited from targets consisting of mixed powder oxides. One target had a composition corresponding to 10 m o l ~ PbO-modified PZT 52/48 (Zr to Ti ratio in the PZT, target A), while the other had the composition corresponding to 10 molto PbO-modified PZT 42/58 (target B). The films in the perovskite structure had ferroelectricity, while the films in pyrochlore had none. The perovskite films deposited from target A had a dielectric constant of 751, a remanent polarization of 20.4/~C/cm 2 and a coercive field of 23.3 kV/cm. The films deposited from target B had a dielectric constant of 654, a remanent polarization of 6.37 t~C/cmz and a coercive field of 12.2 kV/cm. The composition of the former film was PZT 60/40 and the latter, PZT 47/53. The difference in the ferroelectric properties is believed to be in the difference in the compositional ratio of Zr/Ti in the film. (Japan). Akira Okada, J appl Phys, 49 (8), 1978, 4495--4499. 36 3912. Observation of phosphorus pile-up at the SiO2-Si interface. (USA) The Si oxidation rate at high temperatures is increased by heavy P 190
doping. Sputter ion-Auger techniques have been used to investigate the oxide thickness and P concentration after 900°C oxidation with an initial P surface concentration of between 2 × l0 is and 3.2 × 102°/ cm a. Phosphorus was found to pile up in the Si-SiO2 interface region. The maximum P concentration near the interface was found to depend on doping and was (at certain P concentrations) an order of magnitude larger than that predicted by redistribution theory. A vacancy-P-complex model is presented to explain the observed behaviour. A correlation between the selective pile-up of P at the interface and the current gain of planar bipolar transistors is reported. J S Johannessen et al, J appl Phys, 49 (8), 1978, 4453--4458. 36 3913. Electron-solid interactions: their nature and consequences. (USA) During the past two decades electron scattering and emission spectroscopies have become utilized almost universally to characterize the properties of solid surfaces. Two major trends have created this situation: the increasing availability of suitable, convenient experimental apparatus, and the recognition and exploitation of those features of electron-solid interactions which render these measurements sensitive to surface properties. Whereas prior Welch Award lectures have dealt with the former trend, the latter is examined herein. Three concepts are central to an understanding of the interaction of 'low-energy', 10 ~ E ~ I0 a eV electrons with the constituents of solids. First, their strong Coulombic interaction with the valence electrons of the solid renders their mean free paths for inelastic collisions of atomic dimensions, i.e. 2 ~ A ~ 20 A. Thus, elastically scattered or emitted electrons in this energy range must have emanated from the uppermost few atomic layers of the solid. Second, the interactions of these electrons with the core electrons are comparable to those with the valence electrons. Therefore, multiple~ elastic scattering as well as rapid energy loss characterizes their scattering and emission. Third, resonant processes associated with electronic states localized at a surface can be as important as inelastic processes in establishing surface sensitivity. Examples of this phenomenon are found in resonant field emission through adsorbates and resonant photoemission associated with the excitation of transitions characteristic of adsorbed complexes. The major portion of this article is devoted to an indication of how exploitations of these three concepts have led to quantitative surface analysis methodologies for metals and. covalent solids. In the case of polymers and molecular solids, however, one further concept is required: the localization of electronic states caused by fluctuations in relaxation energy. These fluctuations lead to localized molecular ion (or exciton) states rather than extended band states. The final portion of this article is devoted to exploring the consequences of this additional concept and how it led to the invention of yet another electron spectroscopy, contact charge exchange spectroscopy, for the examination of molecular ion states in polymers. C B Duke, J Vac Sci Technol, 15 (2), 1978, 157-169. 36 3914. High resolution Auger sputter profiling study of the effect of phosphorus pileup on the Si-SiO2 interface morphology. (USA) We have used Auger electron spectroscopy in conjunction with sputter etching and crater-edge profiling to study the distribution of phosphorus near the Si-SiO2 interface and the effect of the phosphorus distribution on the width of the interface transition region. The samples studied consisted of thermal oxides approximately 1000 A thick grown on Si (111) substrates with initial phosphorus concentrations up to 6×1020 cm -3. Phosphorus pileup at the Si-SiO2 interface was observed with the phosphorus peak (after correcting for electron excape depth effects) on the Si side within 5 A of the interface. The 1 0 - 9 0 ~ width of the Si-SiO2 transition region as measured by the SiLvv transition varies from 25 (low doping limit) to 38 A (bulk doping level of 6 × 1020 cm-3). Results are interpreted in terms of a recently proposed model for the Si-SiO2 interface. S A Schwarz et al, J Vac Sci Technol, 15 (2), 1978, 237-230. 36 3915. Atomic and electronic structure of semiconductor surfaces. (USA) The electronic structure of surfaces, which can be determined by various electron/ion spectroscopies including ultraviolet photoemission spectroscopy (UPS), is dependent on the surface atomic geometry. Thus, it is possible to determine the surface a t o m i c structure via structure-dependent theoretical analyses of these experimental spectra. Because of the complexity of such systems, a simple but accurate theoretical scheme is required. We show that the valence