Fumiyoshi Miyashita

Compositional structure of dual TiNO layers deposited on SUS 304 by an IBAD technique

Abstract Surfaces of stainless steel SUS 304 were coated with dual titanium oxynitride (TiNO) layers using a nitrogen ion beam-assisted deposition technique. The N ions were accelerated at energy of 0.5–2.0 keV with an intensity of 0.1 mA/cm 2 on the substrate surface. First, a TiNO film was deposited on substrates at 700 °C, and subsequently, another TiN film was deposited on the previous TiNO film surface at 400 °C. Hydrogen carbon nitride, CrFe, and metal carbide M 23 C 6 were produced in the near-surface region of stainless steel during the TiNO deposition at 700 °C, and three characteristic layers consisting of iron nitride, chromium nitride and nickel nitride were formed between the TiNO films deposited and the stainless steel. These characteristic layers disappeared during deposition of the TiNO layer at a temperature of 400 °C.

Preparation of titanium-oxide films by solid-state reactions of titanium/silicon-oxide/silicon structures

Abstract Titanium films were deposited in a vacuum on thermally oxidized silicon. When the titanium/silicon-oxide/silicon structures were heated in oxygen to temperatures of 800–1000°C, titanium oxide films grew on the silicon substrates by a solid-state reaction that involved titanium atoms substituting silicon atoms in silicon oxide. The thickness of the titanium oxide films increased proportionally to that of deposited titanium films. The dielectric constant, resistivity, and breakdown field strength were significantly influenced by treating temperature. The 1000°C-prepared TiO2 films had the dielectric constant of (15–25) eo, the resistivity of 1010 Ω cm, and the breakdown field strength around 106 V/cm.

Plasma-assisted low temperature boridation of pure iron and steels

Abstract An investigation was conducted on the boridation of pure iron and alloy steels, such as S45C, SCM415, SK3 and SKH55. These materials were boridized in a glow discharge of Ar and BCl3 at temperatures as low as 500 °C. Results show that the thickness of boridation increases with increasing substrate temperature and boridation time. The addition agent Mn reduces the boridation rates of pure iron and alloy steels, but C enhances the boridation rates.

Relationship between hardness and lattice parameter for TiN films deposited on SUS 304 by an IBAD technique

Abstract Titanium nitride films were deposited on SUS 304 stainless steel using an ion beam-assisted deposition technique. The N ions were accelerated at energy of 0.5–2.0 keV with an intensity of 0.1 mA/cm 2 on the substrate. Substrates were held at temperatures of 400–770 °C during deposition. For the TiN films, hardness was in the range from 350 to 550 GPa, depending on the N ion-beam energy, while the lattice parameter was dependent on the N ion-beam energy and substrate temperature. The lattice parameter dependence of hardness for the TiN films deposited at temperatures lower than 600 °C differed from that for films deposited at temperatures above 700 °C.

An effect of preheat-treatment on the formation of titanium-oxide films by sintering a titanium/silicon-oxide structure in an oxygen atmosphere

Titanium-dioxide (TiO 2 ) films with a rough surface was grown on silicon by heating a structure of titanium/silicon-oxide/silicon in oxygen at 1000°C. The TiO 2 film growth is attributed to differences in the Gibbs free energy between the titanium-dioxide and the silicon-oxide. Lower temperature preheating of the titanium/silicon-oxide/silicon structure before the solid-phase reaction was favorable for preparing TiO 2 films with a smooth surface on silicon. The grown films were preferentially (110) orientated rutile-TiO 2 polycrystals containing TiSi and TiO phases. A titanium-silicide layer formed near the interface between titanium-oxide and the silicon was employed as a suitable electrode of the capacitors fabricated with the titanium-oxide films. Titanium-oxide films formed by preheating at 400°C had high dielectric constants e 0 of (20-25), resistivities of about 4 X 10 10 Ω cm, and a breakdown field around 10 6 V/cm.

Dual arsenic and boron ion implantation in silicon

Arsenic (As) and boron (B) ions were implanted into silicon (Si) at energies such that their projected ranges coincided. The implanted Si was annealed in argon gas at a temperature of 950 °C for 30 or 300 min. The activation efficiency of the implanted As atoms decreased with an increase in the implant dose of the B ions, and the diffusivity of the As atoms decreased. On the other hand, the diffusivity of the B atoms decreased with an increase in annealing time.

Annealing of Hydrogenated Diamond-like Carbon Films Deposited on Ground Electrode of Plasma Enhanced Chemical Vapor Deposition System

Hydrogenated diamond-like carbon (g-DLC:H) films were deposited on silicon on the grounded electrode of plasma enhanced chemical vapor deposition system and then annealed in Ar gas at temperatures of 300–700 °C for 7.2×103 s after being treated in H2 atmosphere at a temperature of 100 °C for 14.2×103 s. The H2-treated g-DLC:H films had approximately the same thickness, density, and refractive index as the as-deposited DLC:H films; however, their dielectric constants increased slightly with an increase in H2 gas flow rate. The thicknesses, H contents and dielectric constants of the g-DLC:H films annealed at temperatures above 500 °C became very small, even though their densities and refractive indexes of the films increased with an increase in annealing temperature. The properties of the H2-treated g-DLC:H films had approximately the same annealing temperature dependence as those of g-DLC:H films.

Reliability of shallow n+-type layers formed in dual As and B implanted silicon by rapid thermal annealing

Abstract Czochralski-grown 20 Ω cm, B-doped, (100) Si wafers were implanted with combinations of As + and B + ions at energies such that their respective projected ranges coincide at a position of about 30 nm. The implanted dose of As + ions was 1 × 10 16 cm −2 and those of B + ions were in the range of 2.4 × 10 14 – 5 × 10 15 cm −2 . The samples were annealed at 950°C for 10 s using halogen lamps. The junction was formed at a depth of about 120 nm for Si implanted with doses below 2.4 × 10 15 cm −2 of B + ions. The junction, however, could not be formed for Si implanted with a dose of 5 × 10 15 cm −2 of B + ions. The sample changed to n-type by subsequent furnace annealing at 950°C for 30–300 min. The junction depth became shallower with dose of B + ions because an inactive and immobile complex such as AsB is formed in the surface region.

Neutralization and Discharge of Electron Traps in Hydrogenated Diamond-Like Carbon Films Deposited on Ground Electrode by Plasma-Enhanced Chemical Vapor Deposition

Low-dielectric-constant hydrogenated diamond-like carbon (DLC:H) films were deposited on p-type Si substrates on a grounded electrode by plasma-enhanced chemical vapor deposition. The capacitance–voltage (C–V) curves for a returning sweep of bias voltages from positive to negative was positioned above that for a going sweep of bias voltages from negative to positive because many electron traps were present in the DLC:H films. The C–V curve for the going bias voltage sweep first approached that for the returning bias voltage sweep with time, and then such curves separated from each other.

Annealing of TiO2 Films Deposited on Si by Irradiating Nitrogen Ion Beams

Thin TiO2 films were deposited on Si at a temperature of 600 °C by an ion beam assisted deposition (IBAD) method. The TiO2 films were annealed for 30 min in Ar at temperatures below 700 °C. The as‐deposited TiO2 films had high permittivities such 200 eo and consisted of crystallites that were not preferentially oriented to the c‐axis but had an expanded c‐axis. On the annealed TiO2 films, permittivities became lower with increasing annealing temperature, and crystallites were oriented preferentially to the (110) plane.