The initial growth of non-epitaxial thin films was studied and discussed using the concept that thermodynamics controls the unit-structure within the surface diffusion length of deposits, whereas kinetics controls the ensemble-structure on a large scale. Three basic topics, growth mode (island shape), crystalline (island inner) structure, time-dependent properties of island ensemble (island size, distance, and density), are summarized based on the investigation of thin film growth of metals on TiO2, Cu on SiO2 and Ti/SiO2. This study provides fundamental understanding of structural control during thin film growth, and further can be applied to various advanced devices for electronics, photonics, catalysis, and energy applications.

Fine features of the dust distribution in the central region of NGC 4151 have been studied from high resolution images obtained by the Subaru Telescope. The two dust lanes lying along a circum-nuclear ellipse of 40“ ×20” have been recognized to consist of a number of fine filaments and knots. In the inner region, there has been found dust distributed in a bipolar cone region extending to 5” from the nucleus. This cone is exactly complementary to the well-known bipolar ionized gaseous region. A dense knot is seen at 2” SE from the nucleus, but no torus-like feature is recognized. The masses of neutral gas in the outer lanes and in the inner region are estimated as 106M⊙ and 105M⊙ respectively. These observational results are compared with results of numerical simulations of gas dynamics.

TiN films deposited by CVD utilizing TiCl4 and NH3 are widely used in ULSI processes. The residual chlorine in the film is one of the major issues of TiCl4 based chemistry [1–5]. We have examined the kinetics of TiN-CVD using TiCl4 and NH3 as precursors to determine method for controlling the residual chlorine concentration.

We analyzed the deposition rate profiles obtained from a simple tubular isothermal reactor. Deposition was performed over the temperature range from 300°C to 500°C and with varying initial concentrations of TiCl4 and NH3. We found that the deposition rate was independent of the TiCl4 concentration at higher concentrations. The deposition rate was proportional to the TiCl4 concentration in the low concentration range. This phenomenon can be well explained by a Langmuir-Hinshelwood type mechanism. Examination of the deposition rate dependence on the concentration of NH3 showed that both the maximum deposition rate at high TiCl4 concentrations and the first order kinetic rate constant in the lower TiCl4 concentration range were proportional to the NH3 concentration. These results indicate that the deposition was controlled by the Eley-Rideal mechanism. The residual chlorine concentration was found to be proportional to the surface coverage factor of adsorbed TiCl4. We conclude that the best way to obtain good quality TiN films can be obtained theoretically through these kinetic studies.

Several kinds of zeolites, crystal-SiO2 (α-quartz), arnorphous-SiO2 (quartz glass and ultrafine particles) and α-Al2O3, were ablated by an Nd:YAG laser. Generated positive ions from the targets were measured by TOF-MS (time-of-flight mass spectrometry). In the TOF mass spectra of ablated zeolites, TOx (x=0–2, T = tetrahedral atom, e.g., Si, Al), T2Ox (x=1) and T3Ox (x=4,5) were observed up to m/z=170 (m = mass, z = plus charge of clusters). In the spectra due to the oc-quartz, quartz glass and an α-Al2O3 plate, smaller species, T+, TO+ and TO2+, were mainly detected. These results demonstrate that the clusters from zeolites reflect the characters of the mother structure.

In situ measurements of optical absorption and x-ray diffraction for small supported silver particles were performed under defined atmospheres at temperatures below 723 K. We found, for the first time, reversible changes both in optical absorption spectrum and lattice parameter of silver particles against the cyclic exchange of ambient gases between 5% H2/He and 1% 02/He. The present data indicate that the adsorption of oxygen results in a reduction in surface stress of silver particles, leading to a change in the shape of particles.

Submicrometer-size TiO2 powders were continuously produced by vapor-phase hydrolysis of titanium tetraisopropoxide, TTIP, in a tubular-flow reactor. Particle size increased with increasing inlet TTIP concentration, and with decreasing inlet water concentration and temperature. At high water concentrations, primary particles form by instantaneous chemical reactions and particle growth occur by collision and coalescence of the particles. Brownian collision and coalescence theory could predict the experimental effect of inlet TTIP concentration on particle size. The experimental deviations occurred from the theory with increasing temperature were attributed to the changing particle properties with temperature.