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Presents information on a study which described the use of a gold cluster compound as precursor for direct writing with a focused gallium ion beam. Methods; Results; Discussion.

Plasma Immersion Ion Implantation (PIII) is a promising alternative to beam line implantation to produce a single layer of nanocrystals (NCs) in the gate insulator of metal-oxide semiconductor devices. We report herein the fabrication of two-dimensional Si-NCs arrays in thin SiO2 films using PIII and rapid thermal annealing. The effect of plasma and implantation conditions on the structural properties of the NC layers is examined by transmission electron microscopy. A fine tuning of the NCs characteristics is possible by optimizing the oxide thickness, implantation energy, and dose. Electrical characterization revealed that the PIII-produced-Si NC structures are appealing for nonvolatile memories. [ABSTRACT FROM AUTHOR]

Abstract: In this paper, the sputtering-grown [Au 6nm/Co 0.5nm]×10 and [Pt 6nm/Co 0.5nm]×15 superlattices are irradiated using N+ 150keV ions with fluences ranging from 1012 up to 3×1016 N+/cm2. The effect of this ion irradiation experiment on perpendicularly magnetized Co/Au and Co/Pt superlattices is presented. Combining structural and magneto-optical measurements, we reveal the differences in the ion induced mixing between miscible Co–Pt and immiscible Co–Au layered systems. For Co/Pt ones, the progressive ballistic intermixing between Co and Pt leads to a decrease of perpendicular anisotropy and to an in-plane reorientation of the easy axis of magnetization. Although, for Co/Au superlattices the mixing occurs but a thermodynamic phase separation is observed. The structural investigations show that for high fluences the Co layers are disrupted in islands with few nanometer size embedded in Au layers. The perpendicular magnetic anisotropy decreases with fluence but no anisotropy reorientation appears. [Copyright &y& Elsevier]

Abstract: We propose an original approach called a “stencil-masked ion implantation process” for performing a spatially localized synthesis of a limited number of Si nanocrystals within a thin SiO2 layer. In this process, the SiO2 layer is irradiated with 1 keV silicon ions through a stencil mask containing apertures (from 100 nm to 2 μm), and subsequently thermally annealed to create Si nanocrystals. Scanning electron microscopy images show that the implanted areas mimic the mask geometry. Energy-filtered transmission electron microscopy and photoluminescence spectroscopy studies confirm that only the implanted areas are Si nanocrystal rich and light emitting. The smaller nanocrystal size detected near the edges of the implanted areas is attributed to dose reduction effects. This feature leads to a blueshift of the PL energy. Electrical properties of the structures produced are investigated using Al gate MOS capacitors. Room temperature and characteristics exhibit discrete current peaks that are associated with single-electron charging of the nanocrystals and electrostatic interaction of the trapped charges with the tunnelling current. [Copyright &y& Elsevier]

Abstract: This work presents an alternative method for the formation of the top oxide in oxide-nitride-oxide structures. The method utilizes low-energy (1 keV) Si ion implantation into thin oxide-nitride stacks, followed by low temperature wet oxidation. Transmission electron microscopy examination clearly indicates the formation of a three-layer structure, verified also by Time-of flight secondary ion mass spectrometry. The electrical characteristics of the oxide-nitride-oxide stacks exhibit strong trapping effects and excellent retention characteristics resulting to a 1.5 V 10-year memory window at 125 °C. [Copyright &y& Elsevier]

Abstract: In this work, we show how to manipulate two-dimensional arrays of Si NCs in thin (⩽10nm) SiO2 layers by ultra-low-energy (⩽1keV) ion implantation and subsequent thermal annealing. The influence of implantation parameters (dose, energy), annealing conditions (temperature, duration, ambient) and oxide thickness on the NCs characteristics (position, size, density) is reported. Particular emphasis is placed upon post-implantation thermal treatments performed in nitrogen-diluted-oxygen ambient that significantly improve the integrity of the oxide and allow for the fabrication of non-volatile memory devices operating at low-gate voltages. Thermal oxidation in N2-diluted-O2 of high-temperature pre-formed silicon NCs has been also examined and modeled using an extended three-dimensional Deal–Grove model. This model reveals that stress effects, due to the deformation of the oxide, slow down the chemical oxidation rate and lead to a self-limiting oxidation of NCs. The model predictions are in agreement with the experimental results. [Copyright &y& Elsevier]