Silicon nitride films have been deposited using inductively-coupled plasma high-density plasma chemical vapor deposition (HDP CVD), plasma-enhanced chemical vapor deposition (PECVD), and low pressure chemical vapor deposition (LPCVD) methods. Characterization and comparison of the three films were performed using Fourier-transform infrared spectroscopy, secondary-ion mass spectroscopy, Rutherford backscattering spectrometry, and hydrogen forward-scattering spectrometry, in addition to wet-etch rate and stress measurement studies. It was found that silicon nitride films deposited using HDP CVD method have several advantages over the silicon nitride films that were deposited using the LPCVD and PECVD methods. The HDP CVD silicon nitride film can be deposited at much lower temperatures (⩽400 °C) than LPCVD silicon nitride, and has substantially less hydrogen (5.5 at. %) than the PECVD film. In addition, the PECVD film contains some oxygen in the film. The wet-etch rate of HDP CVD silicon nitride film is comparable to that of LPCVD film and is significantly less than that of PECVD film in both hot phosphoric acid and buffered HF solutions. The stress of the HDP CVD film is similarly compressive to the PECVD silicon nitride, and not as highly tensile as that of LPCVD silicon nitride.

High-energy ion scattering ͑HEIS͒, x-ray photoelectron spectroscopy, and x-ray photoelectron diffraction ͑XPD͒ were used to study the growth of thin Ti films on Al͑001͒ surfaces. The Al surface peak area in the backscattered ion spectrum of MeV He ϩ ions, incident along the ͓001͔ direction, was used to monitor the atomic structure of the Ti films during growth. An initial decrease in the area was observed indicating epitaxial film growth. This decrease continued up to a critical film thickness of about 5.5 ML, after which point the structure of the film changed. Titanium films 3, 5, and 9 ML thick were characterized using XPD in the same chamber. Both the HEIS and XPD results show that the Ti films grow with an fcc structure on Al͑001͒. A tetragonal distortion of 2.4% in the fcc Ti film was measured using ions incident along the ͓101͔ direction. Although there is a general similarity of fcc Ti growth on both Al͑001͒ and Al͑110͒, the submonolayer growth regime does show differences for the two surfaces.

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High-energy ion-scattering spectroscopy, x-ray-photoemission spectroscopy, and low-energy electron diffraction (LEED) were used to study the growth of very thin Ti films on Al(110) surfaces at room temperature. The Al surface peak areas in the backscattering spectra of 0.96-MeV He+ ions, incident along the [1 10] direction of AI(110), decreased sharply during the deposition of the first five monolayers of Ti.This suggests a growth model in which a pseudomorphic Ti film with a fcc structure forms, shadowing the Al surface atoms. This model is supported by LEED measurements where sharp diffraction spots persisted with the rectangular symmetry of the substrate lattice structure. Throughout this coverage regime, the attenuation of the Al photopeak intensities as a function of Ti coverage agrees with the attenuation rate calculated using a laminar growth mode. With additional Ti deposition the Al surface peak intensities increase while the Al photopeak intensities remain unchanged. A discussion of possible growth models for the high-coverage regime is presented.

We report the results of high-energy ion backscattering and channeling (HEIS) experiments together with x-ray photoemission spectroscopy (XPS) to determine the interface structure for thin Ni films deposited on Al(110) single crystal surfaces at room temperature. Measurements of the Al and Ni surface peak areas (SPA) show that the Ni atoms do not form a simple overlayer on the Al substrate, but react with and displace Al substrate atoms. The reaction continues with two different rates for a range of Ni coverage from 0 to 8 monolayers (ML) before Ni begins to cover the surface, which differs significantly from the thermally reacted Ni/Al systems. For the first 2.3 monolayers of deposited Ni, the NiAl phase is formed with additional displaced Al atoms at the interface, while for Ni depositions between 2.3 and 8.1 ML, a Ni3Al phase is formed. These phase identifications were made using XPS measurements of the Ni-2p3/2 peak chemical shifts and the shape and separation of the energy loss peak. The reaction at the interface is simulated using the embedded atom method to calculate the interaction between Al and Ni atoms. One ML of Ni atoms was initially distributed in small clusters on the Al surface, and a Monte Carlo approach was used to generate snapshots of the evolving interface. Computer simulations of the HEIS yield from these snapshots show an increase in the SPA of Al in good agreement with our experimental measurements.

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Measurements of the dielectric permittivities in the mixed proton-glass crystal Ko 6&(NH&)0 39H2PO4 are reported from 20 Hz to 200.8 MHz and for fields along both the a and c axes. Between 14 and 50 K, the c-axis permittivity outside the piezoelectric-resonance range shows a temperature-dependent spread in relaxation times but cannot be fit accurately with the Cole-Cole formula. Strong piezoelectric resonance for a field along the c axis was observed in the region between 100 kHz and 10 MHz.