Shoji Miyake

Effect of Low-Energy Ion Flux Irradiation on Synthesis of Superhard Nanocomposite Films

Ti–Si–N films were deposited on the grounded Si(100) substrates by inductively coupled plasma (ICP)-assisted magnetron sputtering. The incident ion flux density at the substrate was varied by controlling the RF power. The effects of low-energy ion flux irradiation on the growth, microstructure and mechanical properties of the Ti–Si–N films have been investigated. An increase in ion flux density causes a transfer of the preferred orientation from TiN(111) to TiN(200). Under the conditions of high-density (~2.0 mA/cm2) low-energy (~20 eV) ion irradiation, low-stressed superhard nanocrystalline TiN/amorphous Si3N4 (nc-TiN/a-Si3N4) film was synthesized at the relatively low deposition temperature of 300 °C.

Roles of rare earth oxide additives in millimeter-wave sintering of AlN

Abstract Roles of rare earth oxide (RE 2 O 3 ) additives in millimeter-wave(MM) sintering of AlN were investigated from the standpoints of phase diagram, heating characteristics of rare earth oxides, and morphology of intergranular oxide phase. In the millimeter-wave sintering of AlN, densification temperature decreased with the decrease of the ionic radius of rare earth ion and was closely related with the eutectic temperature in the RE 2 O 3 -Al 2 O 3 binary system. The lowest densification temperature in the millimeter-wave sintering of AlN with Yb 2 O 3 additive was attributed to the largest heating rate of Yb 2 O 3 ·Al 2 O 3 binary oxide under millimeter-wave radiation. Furthermore, the lowest densification temperature could be attained while selecting the Yb 2 O 3 content so as to form the intergranular phase with the eutectic composition in the Yb 2 O 3 -Al 2 O 3 binary system. The result showed good agreement with the above mentioned during the sintering of Si 3 N 4 with Yb 2 O 3 -Al 2 O 3 additive. From TEM observation, it was verified that film-like intergranular oxide phase formed under millimeter-wave radiation was favorable for attaining high thermal conductivity in the Yb 2 O 3 added AlNs.

Intelligent Materials Synthesis Based on Millimeter-Wave Heating and SPS Methods

Characteristics of heating processing based on millimeter-wave or pulsed high current are discussed from the standpoint of the interaction between electromagnetic energy and solid materials. Capabilities of the electromagnetic processing are indicated by exemplifying several successful results such as millimeter-wave sintering of AlN, millimeter-wave post-annealing of aerosol-deposited PZT films and synthesis of single-phase nano-structured anatase by SPS (or pulsed high current heating). It is shown in these examples that well-characterized properties such as high thermal conductivity and preferential orientation are created by the inherent effect due to the electromagnetic field, which is called microwave or SPS effect in millimeter-wave or SPS processing.

Effects of Copper Doping on Structure and Properties of TiN Films Prepared by Magnetron Sputtering Assisted by Low Energy Ion Flux Irradiation

Ti–Cu–N films containing approximately 0–10 at. % Cu were deposited on Si(100) substrates with high-density low-energy ion flux irradiation by inductively coupled plasma (ICP)-assisted magnetron sputtering. The effects of Cu doping on film microstructures, morphology and properties were investigated. The addition of a small amount of Cu markedly modified the preferred orientation and morphology, and significantly increased film hardness. A Ti–Cu–N film containing 2 at. % Cu has a maximum hardness of approximately 42 GPa. This film was characterized as having a nanocomposite structure, consisting of nanocolumns of TiN crystallites with very small Cu crystallites inside the column boundaries. The hardness increase was attributed to a nanocomposite effect.

Effect of Low-Energy Ion Irradiation on Synthesis of Hard and Superhard Films

This article summarizes briefly our recent research on low-temperature synthesis of TiN, TiN/Cu and TiN/Si films by using inductively coupled plasma assisted magnetron sputtering method. It is shown that the incorporation of high-flux low-energy ion irradiation during deposition strongly affects film growth, structure evolution, morphology and mechanical properties. A main attention is devoted to the synthesis of superhard nanocomposite films at a low deposition temperature. In both TiN/Cu and TiN/Si films the maximum hardness reaches a value higher than 40 GPa.

Characteristics of PZT films fabricated by inductively coupled plasma-assisted aerosol deposition method

Lead zirconate titanate (PZT) films are deposited by an inductively coupled plasma (ICP)-assisted aerosol deposition (AD) method. The influence of RF power was investigated for the deposition rate, microstructure of the films. With our experimental deposition system, the deposition rate was approximately 1 mum/min when using the AD method without plasma assist. On the other hand, the deposition rate rose to over 10 mum/min using ICP -assisted AD method with an RF power of 800 W. The cross-sectional microstructure of the film was very while using an RF power of 800 W and that without plasma assistance.

Preparation of Super-Hard Nanocomposite Films by ICP Assisted Magnetron Sputtering

Super-hard nanocomposite films were deposited on Si(100) substrates with irradiation of a high-density (~2.0 mA/cm2) low-energy (~22 eV) ion flux by an inductively coupled plasma (ICP) assistance to magnetron sputtering process. Low-stress, super-hard nanocomposite Ti-Cu-N and Ti-Si-N films could be synthesized at low deposition temperatures below 300 oC. Prepared films exhibited a pronounced TiN(200) texture and the film hardness was significantly enhanced by the addition of Cu and Si, where a maximum value of 42 GPa at approximately 2 at% Cu addition and 48 GPa at approximately 5.8 at.% Si. Ti-Cu-N films were consisting of nanocolumns of TiN crystallites with dispersion of Cu crystallites around the columnar boundaries. While Ti-Si-N films were characterized as having a nanocolumns of TiN crystallites with amorphous Si3N4 inside the columnar boundaries. The residual compressive stresses of these films were lower than 1.5 GPa and no refinement of crystallite size by the addition of Cu and /or Si was observed, from which the hardness enhancement was attributed to a nanocomposite effect.