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Pt oxide thin films are prepared by sputtering Pt target in an atmosphere containing Ar and O2 gases. Polycrystalline PtO and α-PtO2 films are obtained in O2 flow ratio regions of 30–50% and 80–100%, respectively, at a substrate temperature of 300°C. Electrical resistivity of the PtO film is found to be 1–2 mΩcm and shows almost no temperature dependence. The metallic character of the PtO film is assumed to be suppressed by its poor crystallinity. The α-PtO2 film has a large resistivity of approximately 1 Ωcm with a negative temperature coefficient, which indicates semiconducting characteristics. Thermal stability of PtO and α-PtO2 films in air and in vacuum is studied. These films are stable up to 500°C and 250°C in air and in vacuum, respectively, and are reduced to Pt above these temperatures.

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RhO2 belongs to the family of conducting platinum group metal oxides, which have attracted attention as new capacitor electrode materials for dynamic random access memories (DRAMs) and nonvolatile ferroelectric random access memories (FeRAMs). Rh, Rh2O3, and RhO2 thin films were prepared by sputtering and their XPS spectra were collected with a monochromatic Al Kα x-ray source. This report includes XPS spectra of Rh 3d and O 1s core regions for these films.

Thermal stability of thin poly-Si/Ta2O5/TiN capacitors for dynamic random access memory applicationsThe properties of Ta 2 N and TaN compound films as a diffusion barrier between Cu and Si have been investigated by examining compositional depth profiles obtained by Auger electron spectroscopy. The use of a Ta 2 N barrier is effective for improving the thermal stability of the contact system by raising the silicide formation temperature as compared with the use of a Ta barrier. The contact system of Cu/TaN/Si is fairly stable due to annealing for 1 h even at 750°C. This is interpreted by the stability of the TaN compound, which is chemically inert to Si as well as Cu at this temperature. Eliminating the grain growth of TaN due to annealing is also effective for suppressing the physical diffusion through the barrier.

Ru and RuO2 thin films are considered to be new electrode materials for dynamic random access memories (DRAMs) and ferroelectric nonvolatile memories because of their low resistivity and good thermal and chemical stabilities. In this study these thin films were pepared by reactively sputtering a Ru metal target (99.9% purity) in an argon and oxygen atmosphere. XPS spectra were collected with a PHI 1600 spectrometer equipped with a monochromatic Al Kα x-ray source and a multichannel detector. This report includes XPS spectra of Ru 3d and O 1s core regions for these samples. The binding energy of Ru 3d5/2 is determined as 280.0 and 280.8 eV for Ru and RuO2 films, respectively. The presence of a small amount of Ru with higher oxidation states, such as Ru6+ and Ru8+, is shown at the surface of the RuO2 thin film.

Gallium nitride is grown by plasma-assisted molecular-beam epitaxy on (111) and (001) silicon substrates using sputter-deposited hafnium nitride buffer layers. Wurtzite GaN epitaxial layers are obtained on both the (111) and (001)

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