Yoshiyasu Yamada

Measurement of adsorbed F atoms on a HF treated Si surface using infrared reflection absorption spectroscopy

Si(111) surface treated with HF solution was studied using Fourier transform infrared reflection absorption spectroscopy for the observation of Si–Fx bond absorption and x‐ray photoelectron spectroscopy for the identification of the adsorbates on the Si surface. Two absorption peaks were observed in the range of 905–925 cm−1, and they were assigned to Si–F2 symmetric stretching mode at 918 cm−1 and Si–H2 bending mode at 910 cm−1. The absorption peak of Si–F2 distinctly decreased with de‐ionized water rinse, though the Si–H2 peak hardly changed. The absorption peak of Si–F was not observed in all spectra. This result indicates that F atoms selectively adsorbed at a step region rather than on a terrace region on Si(111) surface after HF treatment.

Electroless plating of Ni thin films using foam of electrolyte

Electroless plating of Ni thin films was achieved in foam of electroplating solution in place of electroplating liquid. Commercial hypophosphite-based solution for Ni electroless plating was added with a surfactant of sulfuric acid monododecyl ester sodium salt (SDS) and bubbled with nitrogen gas to produce airy foam. Ni thin films were deposited by immersing iron substrates in the foam. Although stationary foam was inconvenient for electrodeposition by itself, film growth was enhanced by generating a flow of foam using substrate rotation and by adding SDS to a concentration of 0.1 to 0.3 wt %. No defects attributed to pinholes were observed on the film surface. This method was effective in reducing the net amount of plating solution necessary for film deposition.

High Sensitivity FT-IR-Ras for Silicon Surface Study

A novel configuration for Fourier-transform infrared reflection absorption spectroscopy (FT-IR-RAS) has been devised to study the nature of silicon wafer surfaces in the wide IR irradiation region (especially below 1300 cm −1 ) with high sensitivity. The configuration is basically similar to a conventional one of FT-IR-RAS except that a optical-flat mirror is placed on a silicon wafer surface and the IR beam is incident on the back side of the wafer with a grazing angle. The sensitivity of the novel technique was estimated by the observation of the stretching vibration absorption of the Si-H x bond (2070-2150 cm −1 ) on HF/NH 4 F-treated Si(111) surfaces and Si-O bond (1000-1250 cm −1 ) of chemically oxidized layer ( ∼0.7 nm ) on Si(111) surfaces. The dependence of Si-H x absorption peaks intensities on the composition of HF/NH 4. F solutions was clearly observed. Furthermore, Si-O bond peak corresponding to the longitudinal optical phonon was also detected.

Novel technique of infrared reflection absorption spectroscopy for Si surface study

It is demonstrated that Fourier-transform infrared reflection absorption spectroscopy with a novel arrangement is a powerful technique to study the nature of Si surfaces. The technique was applied to the observation of the Si-H bond absorption (2083 cm-1) on HF- or NH4F-treated Si(111) surfaces and the Si-O-Si bond absorption (1000-1300 cm-1) of oxides on the Si surface formed by native oxidation in air. Both absorptions were clearly observed.

Azimuthal dependence of Auger electron spectra observed with a cylindrical mirror analyzer for Si single crystal and amorphous surfaces

Abstract The azimuthal dependence of Auger electron spectra for Si single crystal and amorphous surfaces, Si(LVV) and Si(KLL), observed with a cylindrical mirror analyzer (CMA) were studied in relation to their low-energy electron diffraction (LEED) patterns. For the Si(111)7 X 7 surface, the peak heights of the Si(LVV) Auger electron spectra were observed to have a variation of 15% (maxima to minima) with an azimuth-angle period of 60°, whereas those for the Si(111) and amorphous Si surfaces, displaying diffuse LEED patterns, showed a spectral deviation within 1.0% standard deviation for the azimuth. It was found that the sharp and diffuse LEED patterns had a close relation with the observed Auger spectra obtained by a conventional CMA having a considerably large detection area of Auger electrons.