We report the writing of very high resolution tungsten containing dots in regular arrays by electron beam-induced deposition (EBID). The size averaged over 100 dots was 1.0 nm at fwhm. Because of the statistical spread in the dot size, large and small dots are present in the arrays, with the smallest having a diameter of only 0.7 nm at fwhm. To date these are the smallest features fabricated by EBID. We have also fabricated lines with the smallest having a width at fwhm of 1.9 nm and a spacing of 3.2 nm.

We report on the statistical analysis of the variations in the size and position of sub-5nm tungsten-containing dots in regular arrays deposited by electron-beam-induced deposition. Full widths at half maximum of the dots are 4.2 and 2.0nm in average. It can be observed in the recorded annular dark-field images that there is a variation in intensity for these dots. We have analyzed these variations and it is found that the relative standard deviation for the mass per dot is 0.092 for the 4.2nm dots and 0.26 for the 2.0nm dots. Comparing this to a relative standard deviation in the estimated number of precursor molecules that are pinned down per dot of 0.041 for the 4.2nm dots and 0.11 for the 2.0nm dots, it appears that the dot-to-dot variation in mass for both dot sizes compares reasonably well with the values expected from Poisson statistics on the number of molecules per dot. It can be concluded that at these dimensions, the statistics on the number of pinned precursor molecules dominates the control of feature sizes.

No abstract

No abstract

Electron energy distributions arising from 2-6-keV protons grazingly incident on an Al͑111͒ surface are reported for two different azimuthal angles of incidence and for a range of observation angles. Although the protons have energies that are an order of magnitude below the generally accepted threshold for plasmon excitation, the spectra strongly suggest that excitation and subsequent decay of bulk plasmons takes place. To explain this remarkable observation we propose that a subthreshold proton may excite a bulk plasmon in a process in which not only energy and momentum are transferred to the plasmon but also, mainly momentum, to the target.