A new type of standard channel electron multiplier (CEM) for quantitative Auger electron spectroscopy has been developed by members of Hardware Subcommittee, VAMAS-SCA-JAPAN. This was designed to provide a function of selfcalibration with dualoperating mode of CEM and Faradaycup. In preliminary AES measurements of a polycrystalline Au sheet by use of the so-called VAMAS-type standard CEM, it was demonstrated that the instrument could be operated well in both CEM and Faradaycup modes. The good agreement of both spectra except in the low kinetic energy region suggested that the energy dependency of the standard CEM was almost flat in the energy range from about 100eV to 2500eV. From these results it could be said that the use of the VAMAStype standard CEM will make the calibration of the intensity scale of AES easier and more practicable.
The atomic structure of (NH4)2 Sx-treated and annealed GaAs surface has been investigated using scanning tunneling microscopy (STM) and atomic force microscopy (AFM). STM observation revealed that most of the GaAs flat surfaces showing 2×1 structure are terminated with Ga-S bonds and that the sulfur monolayer forms dimers after being annealed at 510°C. Surface structural parameters such as S-S dimer bond length and Ga-S distance in the  direction are determined and found to be in good agreement with the theoretically calculated values. A sulfur overlayer is also observed. The second S layer has a 2x structure in both  and  directions, but the third layer does not show any ordered structures. AFM observation shows that the S-treated and annealed GaAs is covered with a thin S layer in a wide area and that many circular S residuals reside on the surface. These results reveal that the surface is covered not only with an S monolayer but also with an S multilayer even with high-temperature annealing at 510°C.
Two kinds of the resonant-Auger (spectator and participator) decay processes were studied for 2P3/2(L3)→4d(unoccupied) in Y2O3, ZrO2 and Nb2O5. The L3M4, 5M4, 5 Auger peaks are split into spectator and normal Auger peaks around the resonant photon energy. It is also found that the kinetic energy of the former peak shifts with the incident photon energy. This can be explained in connection with the broad band structure of the unoccupied orbitals. Furthermore the branching ratios of 3d5/2 to 3d3/2 were found to fluctuate drastically around the absorption edge. This is due to the participator Auger (direct-recombination) process and was interpreted in terms of the symmetry restriction between the initial and the final state which includes the photoelectron wave.
Photon-stimulated ion desorption (PSD) from chlorine-adsorbed GaAs(100) and GaAs(111)B surfaces is investigated by using synchrotron radiation. Ga+ desorption was observed only from the Cl-adsorbed GaAs(100) surface while Cl+ desorption was observed from the both surfaces. These results are explained from the viewpoints of the difference in bonding state of chlorine atom at two types of GaAs surfaces. The photon energy dependence of Cl+ desorption yield suggests that the photo-ionization of Cl core levels is much more effective for the ion desorption than that of As core levels.
Under the condition of low chemical potential, a 2×3 and other new superstructures, the axes of which are in directions different from crystal axes, were observed for Se-treated GaAs(001) surface by scanning tunneling microscopy (STM). These structures were explained by the dimer model where buckling structures of the Se dimers play important roles. The controversial 2×1 dimer structure was also observed; however, the corrugation in the 2×1 cluster was very small (-0.01nm), which is considered to have caused difficulties in the observation of this surface by STM.
Strain in GaAs island grown on GaP (001) substrate was calculated by a model proposed by Keating. This model assumed that the interaction between atoms was composed of two terms, central and noncentral forces. The calculations were performed by assuming the island shape to be a plate 0 of 2 to 10 ML in height and 8 to 46Å in length. Minimization of the strain energy was computed with a simplex method. The results show that the strain relaxes at the free edge of the island, and the degree of the relaxation depends on the width of the island. The relaxation is larger in a narrower island. This is consistent with the coherent island model recently proposed by Snyder et al.
Two prototype inner-magnet type micro-sputtering apparatus, named “KA-Jr.” and “HAMSA” by the authors, have been constructed. The concept of this inner-magnet type apparatus is quite different from that of the conventional sputtering apparatus into which substrates must be inserted. These new apparatus are suitable to make deposition or etching on any area of the substrate that is too large to insert into the vacuum chamber or on biological materials. The “KA-Jr.” can be applied to repair a damaged part of a thin film coated on a large window glass or defects of electrode lines formed on a photo mask or a liquid crystal panel by selecting either deposition or etching mode by chanin the anode position in this apparatus. On the other hand, “HAMSA” is very small and easy to handle. Therefore it is useful for forming dental caries preventing films on teeth in vivo and in making micro-marking on curved surfaces of shells and fishes.
A high resolution angle-resolved electron spectrometer (HR-ARES) system with extremely high vacuum and extremely low residual magnetic field has been developed. This system can be used for the precise measurements of angular distribution of elastically or inelastically scattered electrons (photoelectrons, Auger electrons) excited by the incidence probes of X-ray (Mg Kα) and electron beams. Since the main chamber was made of 5 mm-thick mu-metal alloy which has high magnetic-shieldng ability, the residual magnetic field in the inner space was found to be decreased to less than 4 mG. This extremely low magnetic field enables the precise angle-resolved measurements of ultralow energy electrons of about 1 eV. Using our sophisticated UHV techniques, the HR-ARES system with many equipments for surface analysis and treatment has attained the extremely high vacuum of less than 10-9 Pa.
Ethene adsorption on Cu(110) surfaces was investigated by infrared reflection absorption spectroscopy (IRAS) and temperature programmed desorption (TPD). The end-on and tilted type species of adsorbed ethene were observed on clean Cu (110) surface at 110K. The layer of the end-on ethene on Cu (110) surface was drastically changed by annealing the surface above 160 K followed by cooling to 110 K under ethene atmosphere. The π-adsorption took place on oxygenmodified Cu (110) surface, where the oxygen induced (2×1) reconstructed phase was formed. It was suggested that the surface structure was more essential for orientation of the π-adsorbed ethene than the long range effect. The heat of adsorption of π-bonded ethene on the (2×1)-O/Cu (110) surface was estimated to be 32±7 kJ/mol from the analysis of the adsorption isobar obtained by IRAS.
The discrete variational (DV)-Xα cluster model is used to study the surface structure of Ge film which developed on Si (001) substrate using Te as a surfactant. The X-ray photoelectron spectra were calculated and compared with experimental data. From the comparison, it is found that Te dimers adsorb on the hollow site of Ge (001) -2×1 surface and their bonding direction is perpendicular to that of Ge dimers. The results suggest that the Te dimers terminate the dangling bonds of Ge film surface and exchange their site with evaporated Ge atoms at the adsorption site.