Low-energy electron-induced reactions in condensed matter

A bifocal lens of the Cohen lens design utilizing phase zone plate optics and a facet depth of one-half wavelength of the design wavelength, where the primary focal points are at two orders, specifically the 0 th and 1 st orders, and the brightness at each primary focal point is equal at about 0.40.

Diffractive multifocal optical device

A multifocal optical device is provided for focusing light traveling parallel to an optical axis of the device. The multifocal optical device comprises a multifocal phase zone plate including at least two annular zones disposed substantially concentrically about the optical axis and spaced in a radial dimension from the optical axis in proportion to the square root of q, where q is an integer zone number; and an absorbing material disposed on a portion of ones of the annular zones for absorbing a portion of the light.

Multifocal optical device with spurious order suppression and method for manufacture of same

A diffractive multifocal optical element comprising a phase zone plate of a Cohen lens design containing rotationally symmetrical, curved repetitive patterns designed to operate at a specific wavelength and which are also curved in r 2 space.

Multifocal optical device with novel phase zone plate and method for making

Photoexcited chemical‐vapor deposition (CVD) and etching using synchrotron radiation as an exciting light source were experimentally demonstrated. CVD of silicon nitride film and etching of Si and SiO2 by SF6+O2 gases are described in detail. In several reaction systems, it was found that the surface photoexcitation was an important mechanism. Reaction models for gas‐phase excitation and surface excitation were proposed.

Synchrotron radiation-excited chemical-vapor deposition and etching

The photochemical vapor deposition of SixNyHz films (y/x≤11) is demonstrated, using the vacuum UV (VUV) from synchrotron radiation (SR) for the first time In the configuration with the beam axis parallel to the substrate surface, the deposition rate achieved is about 005 nm/min for a 100 mA ring current and a 27/133 Pa SiH4/N2 pressure Values of about nine times larger are obtained in the perpendicular configuration It is shown that decomposition of adsorbed molecules by SR irradiation is the primary process involved in deposition in the perpendicular configuration

Synchrotron radiation‐excited chemical vapor deposition of SixNyHz film

It was found that a carbon film in an oxygen gas is etched by irradiation of synchrotron radiation (SR). The etching rate was about 3 nm/min for a 100‐mA ring current in an oxygen pressure of 26.7 Pa, and it increased in proportion to the square root of the oxygen pressure and the incident SR beam power. An analysis of the etched pattern indicates that the surface excitation induced by SR irradiation plays the predominant role in the described etching reaction.

Synchrotron radiation-induced etching of a carbon film in an oxygen gas

A new phase zone plate with suppressed higher-order flux is proposed and optimum design calculations are made for Al. While the first-order collecting efficiency is equal to that of conventional Fresnel zone plates (∼10%), the ratio of the higher-order flux energy to the first-order energy can be suppressed to <10−3–10−6 in the 300–600-A wavelength range.

Higher-order suppressed phase zone plates.

The dependence of the deposition rate on the radius of the synchrotron radiation (SR) beam, on the incident angle to the substrate and on substrate configuration to SR beam is investigated in SR-excited chemical vapor deposition of silicon nitride films. Through the experimental results and related analyses, the contribution of gas-phase excitation near the substrate surface to deposition is clarified. In addition, by evaluating the numbers of photoelectrons and secondary electrons emitted from the SR-irradiated substrate, the contribution of low-energy secondary electrons to the excitation of gas-phase and adsorbed molecules is discussed. Finally, a reaction model including the excitation of the core electrons of substrate constituent atoms and the contribution of the interaction between generated low-energy secondary electrons and gas-phase molecules and adsorbates near/at the surface is proposed to explain the material dependence of the film composition observed in the SiH4+NH3 gas system.

Role of low-energy secondary electrons in synchrotron radiation-excited chemical vapor deposition of silicon nitride films

This paper presents the dispersive characteristics of a Ta film one-dimensional Fresnel zone plate (FZP) measured using synchrotron radiation as a light source. Spectral spatial distributions of the FZP linear monochromator output beam are recorded on an X-ray film. The observed distributions are well explained by the FZP's chromatic aberration. The spectral bandwidth of the monochromator output beam decreases proportional to the slit width and saturates at approximately the value limited by the size of the focused image of the synchrotron radiation source.

Hakaru Kyuragi

Papers

Synchrotron radiation‐excited chemical vapor deposition of SixNyHz film

Synchrotron radiation-induced etching of a carbon film in an oxygen gas

Higher-order suppressed phase zone plates.

Role of low-energy secondary electrons in synchrotron radiation-excited chemical vapor deposition of silicon nitride films

Dispersive characteristics of one-dimensional Fresnel zone plates measured using synchrotron radiation