A physical model based on the multiple charge state vacancy statistics is proposed to express the boron diffusivity in silicon during the deposition step using the BN disk as a diffusion source in an inert ambient. The diffusion equation with concentration dependent diffusivity is solved numerically. A universal shape of the normalized profiles is observed. The surface concentration of the deposited layer has been determined experimentally. The calculated sheet resistance as a function of deposited time and temperature is in good agreement with the measured data. With a slight modification, this simple vacancy statistics model can also be applied to other deposition sources.* Electrochemical Society Active Member.

We observe a relation between closed strings tachyons and one-loop instabilities in non-supersymmetric non-commutative gauge theories. In particular we analyze the spectra of type-IIB string theory on C 3 /Z N orbifold singularities and the non-commutative field theory that lives on D3 branes located at the singularity. We find a surprising correspondence between the existence or not of one-loop low-momentum instabilities in the noncommutative field theory and the existence or not of tachyons in the closed string twisted sectors. Moreover, the relevant piece of the non-commutative field theory effective action is suggestive of an exchange of closed string modes. This suggests that non-commutative field theories retain some information about the dynamics of the underlying string configuration. Finally, we also comment on a possible relation between closed string tachyon condensation and field theory tachyon condensation.

The sheet resistance and junction depth as a function of time at various temperatures have been obtained for the deposition of boron in silicon by using a BBr~ liquid source. A simulation program incorporating a more realistic moving boundary condition is developed to analyze the deposition process under oxidizing atmosphere. By fitting numerical solutions to experimental data, the moving interface velocity and diffusion coefficient are determined. The profile of deposited layers as a function of doping gas composition can be modeled by the change of silicon selfinterstitial concentration. The solid solubility of boron in silicon as a function of temperature has been determined. Different surface concentrations corresponding to different thicknesses of the boron-rich layer can be explained by the translation of the BRL-Si interface. * Electrochemical Society Active Member. Key words: diffusion, boron deposition, BBr8 source. ) unless CC License in place (see abstract). ecsdl.org/site/terms_use address. Redistribution subject to ECS terms of use (see 128.6.218.72 Downloaded on 2015-04-13 to IP

Gallium arsenide crystals were grown from Ga‐rich solutions having initial compositions near the 900°C isotherm of the Ga‐As‐Zn ternary phase diagram. They were grown over the temperature range from 900° to 700°C. The concentration of Zn in normalGaAs appears to vary linearly with the Zn atomic fraction in the liquid at lower doping levels and with the square root of the atomic fraction of Zn in the liquid at higher doping levels. In fitting the experimental data to the theoretical expression for the solid solubility, the intrinsic carrier concentration of normalGaAs was found to be about 8×1017 cm−3 . The corresponding temperature has been estimated to be 825°–850°C.

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