Articles you may be interested inDevelopment of a multifunctional surface analysis system based on a nanometer scale scanning electron beam: Combination of ultrahigh vacuum-scanning electron microscopy, scanning reflection electron microscopy, Auger electron spectroscopy, and x-ray photoelectron spectroscopy Rev.Conductive dots, wires, and supertips for field electron emitters produced by electron-beam induced deposition on samples having increased temperature

The nanometer-scale oxidation of Si(lQ0) surfaces in air is performed with an atomic force microscope working in tapping mode. Applying a positive voltage to the sample with respect to the tip, two kinds of modifications are induced on the sample: grown silicon oxide mounds less than 5 nm high and mounds higher than 10 run (which are assumed to be gold depositions). The threshold voltage necessary to produce the modification is studied as a function of the average tip-to-sample distance. Q 1995 American Institute of Ph.ysics.

No abstract

The first stages of platinum electroless deposition on (100) Si from hydrogen fluoride solutions are studied by tapping mode atomic force microscopy (AFM), transmission electron microscopy (TEM), and x‐ray photoelectron spectroscopy (XPS). Tapping mode AFM and TEM provide a morphological characterization of the samples, while XPS accounts for the compounds present on the surface. During immersion in an aqueous HF solution containing a platinum salt, platinum nucleates on the silicon substrate while the surface is etched. The deposited nuclei are polycrystalline, highly pure, and strongly silicidated at room temperature. Metal deposition takes place by means of a redox reaction in which silicon atoms oxidize, supplying the electrons for the metal to reduce. For all substrates, platinum silicide is formed during deposition at room temperature, suggesting a competition between the deposition of pure metal by an electrochemical mechanism and the formation of the silicide by direct reaction. For equal deposition times, more platinum deposits on p‐type substrates than in n+. p‐Type substrates, moreover, undergo a general increase in roughness in the bare silicon areas, while n‐type substrates present a lower and more local etching. This seems to indicate that electroless platinum deposition is somehow hindered on n+ substrates.

Atomic force microscopy, working in contact and tapping modes, has been used to probe the mechanical response of octadecyltrichlorosilane, CH3−(CH2)17−SiCl3 (OTS), self-assembled ultrathin films grafted on silicon-treated surfaces. To assess the adhesion hysteresis and the elasticity of the films, we have performed loading and unloading experiments in contact mode. The effect of compression is observed while the load is being applied to the film. Once the load is fully removed, the film remains compressed showing a clear deviation from perfect elasticity, with relaxation times in the range of 0.1 s. In the tapping mode, the loading/unloading experiments show again the deviation from perfect elastic recovery of the films. Upon loading, three different regions are encountered. These can be associated with an initial disorder of the chains produced by the indenting tip, followed by a smooth compression and a final hardening effect due to repulsive forces between the compressed chains. The tapping mode is also used to provide strong evidence of a “cushioning” effect. The tribological properties of our OTS layers seem to be influenced by molecular disorder of the alkyl chains.