Masaharu Watanabe

Hole Generation without Annealing in High Dose Boron Implanted Silicon: Heavy Doping by B12 Icosahedron as a Double Acceptor

A high hole concentration region of about 1×1021 cm-3 was generated without any post-annealing by the implantation of high doses of boron into silicon substrates. X-ray photoelectron spectroscopy (XPS) measurement and Fourier transform IR spectroscopy (FTIR) absorption spectra revealed that B12 icosahedra were created in as-implanted samples. A new model of the generation of holes is proposed in which B12 icosahedron acts as a double acceptor.

Effect of SiO2 Thickness on Dielectric Breakdown Defect Density Due to Surface Crystal-Originated Particles

Accidental dielectric breakdown defects in thermally grown SiO 2 films on p-type, Czochralski-grown, chemo-mechanically polished Si wafers with various optical precipitate profiling defect densities were investigated. The accidental oxide defect densities were estimated by time-zero and time-dependent dielectric breakdown measurements. In both dielectric breakdown measurements, the total accidental dielectric breakdown defect density in 10 nm thick oxide was almost the same as that of 25 nm thick oxide. The total accidental oxide dielectric breakdown defect density was almost consistent with the crystal originated particle (COP) density that appeared on the original wafer surface. This result indicates that only the COPs that are present on the wafer surface prior to gate oxidation are responsible for the accidental dielectric breakdown defects The results in this report were obtained by a round robin of measurements from six wafer vendors and two researchers.

A System for Detecting Metal Atoms Ejected from Solid Surfaces by Means of Multiphoton Resonance Ionization

A multiphoton resonance ionization system combined with a time-of-flight technique has been developed. It consists of an excimer laser-pumped dye laser, a SHG crystal for generation of the second harmonic radiation and a time-of-flight system for measuring the velocity of photoions. Using this system, the resonance wavelengths for multiphoton ionization of Ni and Fe atoms are determined, and the ionization efficiency for sputtered Ni is demonstrated to be saturated to 100%.

Invited) Controlled Oxygen Doping in Silicon

Oxygen concentration in as-grown silicon crystals was controlled by doping oxygen intentionally. Oxygen concentration depended linearly on the surface area of fused quartz pieces placed at the bottom of Si3N4 crucible which is made by CVD using SiCl4+NH3→Si3N4 reaction.