SiO 2 films deposited on Si and on thermal SiO2 by tetraethylorthosilicate [TEOS, Si(OC2H5)4]/O3 atmospheric-pressure chemical vapor deposition (APCVD) were analyzed by thermal desorption spectra (TDS). The TDS results show that more silanols were incorporated during deposition and more water was absorbed during and after deposition in films deposited on Si substrates than on thermal oxide substrates. The latter result indicates that the elimination of water by-products is not the limiting step in TEOS/O3 APCVD. Based on the former result, a silanol model was proposed for the surface processes. On surfaces with a uniform and high density of silanol sites, or on which silanols readily form under TEOS/O3 APCVD conditions, the active silanol groups in the gas phase contribute to film formation and replenish silanol sites, resulting in continuous, high growth rates. On surfaces with few silanol sites, it is difficult to form silanol sites and the nonsilanol-containing polysiloxanes contribute to film formation, resulting in continuous, low growth rate. This model explains well both the surface dependence and the memory effect of TEOS/O3 APCVD.

A plasma-enhanced atomic layer deposition (PEALD) process for the growth of tantalumbased compounds is employed in integration studies for advanced copper metallization on a 200- mm wafer cluster tool platform. This process employs terbutylimido tris(diethylamido)tantalum (TBTDET) as precursor and hydrogen plasma as the reducing agent at a temperature of 250°C. Auger electron spectrometry, X-ray photoelectron spectrometry, and X-ray diffraction analyses indicate that the deposited films are carbide rich, and possess electrical resistivity as low as 250νΔcm, significantly lower than that of tantalum nitride deposited by conventional ALD or CVD using TBTDET and ammonia. PEALD Ta(C)N also possesses a strong resistance to oxidation, and possesses diffusion barrier properties superior to those of thermally grown TaN.

A new structure of piezomotor using a flextensional coupler is proposed. Two longitudinal actuators and an elliptical shell constitute its frame. The basic structure and the operating mode are first presented. The coupling between a translation mode and a flexion mode generates an elliptic motion at shell tops. The design method based on a finite element model and an electromechanical equivalent circuit permits the structure dimensioning. Construction of motor prototypes indicates the reliability of the principle, a good agreement with design results and interesting motor performances. †

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We found that surface protrusions of chemical vapor deposited TiN films are caused by reactions between copper contaminants and the silicon substrate. Depending on the size of the copper contaminant, two kinds of defects were formed: copper silicide (CuSi) and silicon dioxide. The silicon dioxide is formed because of the catalytic role of copper silicide. The defects grow both into and out of the silicon substrate. In the formation of copper silicide and silicon dioxide, copper, silicon, and oxygen are the major participating species.