Showing papers by "James W. Mayer published in 1990"

Electronic Materials Science: For Integrated Circuits in Si and GaAS

Abstract: For an advanced undergrad/first grad course in materials science, covering thin film materials.

Selective deposition of tungsten on TiSi2

Abstract: An improved process for preparing selective deposition of conductive metals on disilicide encroachment barriers allows the construction of integrated circuit components wherein the metal/disilicide interface is substantially free of O and/or F contamination. The level of interfacial oxygen and/or fluorine contamination in the selective W deposition on the TiSi 2 was substantially reduced or eliminated by first forming a C49 TiSi 2 phase on a substrate, selectively depositiong W on the C49 TiSi 2 phase and thereafter annealing a a (minimum) temperature sufficient to convert the high resistivity phase C49 TiSi 2 to the low resistivity phase C54 TiSi 2 .

Resistivity and morphology of TiSi2 formed on Xe+‐implanted polycrystalline silicon

Abstract: Xe ion irradiation of polycrystalline silicon before Ti deposition is found to affect subsequent silicide formation. Silicide films were prepared by implanting 60, 100, or 240 keV Xe+ ions into 500‐nm‐thick undoped polycrystalline silicon before depositing Ti and annealing in vacuum. Preimplantation altered the subsequent silicide resistivity, x‐ray diffraction patterns, and morphology as compared to films prepared on unimplanted polycrystalline Si substrates. We found that minimal TiSi2 resistivities were achieved at lower temperatures with preimplantation, indicating that the Xe‐implanted substrate promotes a lower temperature transition from the metastable C49 phase to the low‐resistivity equilibrium C54 phase of TiSi2. X‐ray diffraction results confirmed the lower temperature formation of the C54 phase with preimplantation. Low‐temperature annealing (650 °C, 30 min) of 6×1016 cm−2, 240 keV Xe+‐implanted samples yielded low‐resistivity (∼22 μΩ cm) silicide films, while simultaneously annealed samples w...

Observation of multiple precipitate layers in MeV Au++‐implanted silicon

Abstract: Room‐temperature MeV Au++ implantation into silicon with energies above 1.8 MeV shows a splitting of the Au concentration profile in the Rutherford backscattering spectrometry (RBS) spectra. Cross‐section transmission electron microscopy micrographs show two distinct regions of Au precipitates corresponding to the peaks in the RBS spectra. The double peaks can be explained by the segregation of Au into the highly damaged region near the end of the implant range and Au segregation along a dislocation network. These dislocations arise from dynamic beam annealing during the implant and act as paths for rapid diffusion. Precipitation occurs when the Au concentration exceeds the solubility limit. Lower energy implants resulted in the expected Gaussian distributions.

Characterization of BaTiO3 Thin Films Deposited by Pulsed-Laser Ablation

Abstract: Thin films of barium titanate (BaTiOs) have been deposited by pulsed-laser ablation onto (001)-oriented MgO substrates. The films were epitactic as evidenced by both x-ray diffraction and ion-channeling techniques. The film surface appeared smooth and contained a low density of particulates. This latter feature is believed to be due to the formation of target pellets having a very high density.