We have investigated the dependence of leakage current and capacitance of Pt/Ba0.5Sr0.5TiO3/Pt capacitors on annealing temperature under high vacuum conditions. It is observed that leakage currents increase asymmetrically for negative and positive bias voltage with increasing annealing temperature. A model of leakage current and capacitance characteristics has been proposed on the assumption of generation of oxygen vacancies by annealing at the interfaces of the dielectric film adjacent to the Pt electrodes. The model predicts the oxygen vacancies of about 1020 cm−3.

It has been found that selective thermal desorption of SiO2 on Si (111) substrate is induced by electron-beam irradiation. By using this selective thermal desorption, a nanofabrication technique has been realized by focused electron beams. Open windows of 10 nm width in a SiO2 film have been fabricated by this technique. A pattern transfer from the open windows to thin Si films has also been performed by Si growth and subsequent heating. This has produced Si wires of 10 nm width.

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A scanning reflection electron microscope (SREM) combined with a scanning tunneling microscope (STM) has been developed for the purpose of nanoscale structure fabrication under ultrahigh vacuum conditions. A STM unit consists of a piezoelectric tube scanner and an inch runner for coarse and fine approach of a STM tip. A sample holder and the STM unit have six drive axes relative to an electron gun for simultaneous observation by SREM and STM. Energy-dispersive x-ray spectroscopy equipment is also installed for surface sensitive elemental analysis. It has been demonstrated that on a Si(111)7×7 surface atomic steps and 7×7 unit, cells can be observed in the SREM and STM images, respectively, and that surface elements with less than 1 ML thickness are detectable.

We have found that terrace contrast of oxidized Si(001) substrate observed with a scanning reflection electron microscopy (SREM) is reversed by progress in thermal oxidation by one atomic layer of Si. The cause for such terrace contrast reversion is that reflection electron intensity depends on Si-bond direction at oxide/Si interface. This fact was confirmed by calculations based on a multiple scattering theory. The motion of oxide/Si-bulk interface can be, thus, observed by SREM. The reversion and continuous change of the terrace contrast indicate that oxidation occurs monolayer by monolayer on Si(001) substrate.