We have grown compositionally graded GexSi1−x layers on Si at 900 °C with both molecular beam epitaxy and rapid thermal chemical vapor deposition techniques. Triple-crystal x-ray diffraction reveals that for 0.10<x<0.53, the layers are totally relaxed. GexSi1−x cap layers grown on these graded layers are threading-dislocation-free when examined with conventional plan-view and cross-sectional transmission electron microscopy. Electron beam induced current images were used to count the low threading dislocation densities, which were 4×105±5×104 cm−2 and 3×106±2×106 cm−2 Eq. 2×106 cm−2 for x=0.23 and x=0.50, respectively. Photoluminescence spectra from the cap layers are identical to photoluminescence from bulk GexSi1−x.

The preparation of Ru and RuO2 thin films by organometallic chemical vapor deposition and an investigation of the films' properties are reported. Ru is of interest for metallization in integrated circuit fabrication because its thermodynamically stable oxide, RuO2 , also exhibits metallic conductivity. As a result, oxidation during processing of Ru is a less critical concern than in current metallization technology. Taking advantage of the benefits of chemical vapor deposition, such as conformal coverage and low temperature, damage‐free deposition, we have deposited Ru, RuO2 , and normalRu/RuO2 by pyrolysis of three organoruthenium complexes. Films of a given phase composition were deposited under a wide variety of conditions and exhibited large variations in electrical resistivity and carbon content. The best Ru film, produced from Ru3false(CO)12 at 300°C in vacuum, had a resistivity of 16.9 μΩ‐cm and exhibited excellent adhesion to Si and SiO2 substrates. The best RuO2 film, produced from normalRufalse(C5H5)2 at 575°C in O2 , had a resistivity of 89.9 μΩ‐cm and similarly exhibited excellent adhesion. Rutherford backscattering studies show that Ru and RuO2 films are effective diffusion barriers between Al and Si up to annealing temperatures of about 550° and 600°C false(1/2 normalh exposurefalse) , respectively. Thus, they are significantly better than the currently used W films, which are only effective to about 500°C.

Oxynitrides can suppress the diffusion of boron from the polycrystalline silicon gate electrode to the channel region of an ultralarge scale integrated device, and are therefore important potential substrates for thin SiO2 gates. Direct oxynitridation of Si in N2O is a simple and manufacturable N incorporation scheme. We have used rapid thermal oxidation to grow O2- and N2O-oxides of technological importance (∼10 nm thick) in the temperature range 800–1200 °C. Accurate measurements of the N content of the N2O-oxides were made using nuclear reaction analysis. N content increases linearly with oxidation temperature, but is in general small. A 1000 °C N2O-oxide contains about 7×1014 N/cm2, or the equivalent of about one monolayer of N on Si (100). Nonetheless, this small amount of N can retard boron penetration through the dielectric by two orders of magnitude as compared to O2-oxides. The N is contained in a Si-O-N phase within about 1.5 nm of the Si/SiO2 interface, and can be pushed away from the interface by O2-reoxidation. We have measured Si/SiO2 interfacial roughness by x-ray reflectometry, and found that it decreases with increasing oxidation temperature for both O2- and N2O-oxides, although the N2O-oxides are smoother. The enhanced smoothness of N2O-oxides is greater the greater the N content. N2O-oxides are promising candidates for thin ultralarge scale integrated circuit gate dielectrics.

Thermally grown Si(001)/SiO2 samples were studied by x-ray reflectivity. Fits of model electron density profiles to the data reveal the existence of an interfacial layer at the Si/SiO2 interface up to 15-Å-thick, with density higher than either the crystalline Si or the main oxide layer. This density of the layer is reduced by a postoxidation anneal.

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