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This study introduces a method for copper film growth with Cl 2 plasma. The method consists of two stages: generation of the precursor, CuCl, by etching a bulk copper target, and reduction of CuCl adsorbed on a substrate surface. In both reactions, atomic chlorine ͑Cl*͒ generated from the same Cl 2 plasma played the leading role. Copper films were grown on a TaN film ͑50 nm͒ adhesively at a growth rate of 118 nm/min. The obtained copper films had a resistivity of 2.0 ⍀ cm and a Cl content of less than 15 ppm. This method also makes it possible to fill the 0.1 m gap with an aspect ratio of 10.

Passive-to-active oxidation transitions in chemical vapor deposited ͑CVD͒ SiC under low total pressures ͑0.8-440 Pa͒ in the temperature range 1250-1700°C have been investigated. A mass spectrometer sampling system equipped with a xenon image furnace was used to detect the transition points. As the temperature increased under fixed oxygen pressure, the ion current at m/e 28, which corresponds to the partial pressure of CO͑g͒ on the surface of CVD-SiC samples, indicated two distinct changes in the measured partial pressure of CO͑g͒. One can be assigned to a transition from the passive oxidation to bubble formation and the other can be assigned to a transition from bubble formation to active oxidation. An explanation is proposed based on available kinetic and thermodynamic data for these.

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We have studied rooted spiral trees in dimensions 2 , 3 and 4 by exact enumeration and by Monte Carlo methods. Numerical estimates of critical exponents thus obtained support the hypothesis that a dimensional reduction by four occurs in this problem. A possible mechanism of the origin of this dimensional reduction is proposed.