We have determined electron inelastic mean free paths (IMFPs) in C (graphite), Si, Cr, Fe, Cu, Zn, Ga, Mo, Ag, Ta, W, Pt and Au by elastic-peak electron spectroscopy (EPES) using Ni as a reference material for electron energies between 50 and 5000 eV. These IMFPs could be fitted by the simple Bethe equation for inelastic electron scattering in matter for energies from 100 to 5000 eV. The average root-mean-square (RMS) deviation in these fits was 9%. The IMFPs for Si, Cr, Fe, Cu, Ag, Ta, W, Pt and Au were in excellent agreement with the corresponding values calculated from optical data for energies between 100 and 5000 eV. While the RMS differences for graphite and Mo in these comparisons were large (27 and 17%, respectively), the average RMS difference for the other 11 elements was 11%. Similar comparisons were made between our IMFPs and values obtained from the TPP-2M predictive equation for energies between 100 and 5000 eV, and the average RMS difference for the 13 solids was 10.7%; in these comparisons, the RMS differences for Ta and W were relatively large (26% for each). A correction for surface-electronic excitations was calculated from a formula of Werner et al.; except for Si and Ga, the average correction was 5% for energies between 150 and 5000 eV. The satisfactory consistency between the IMFPs from our EPES experiments and the corresponding IMFPs computed from optical data indicates that the uncertainty of these IMFPs is about 11% for electron energies between 100 and 5000 eV. Similar comparisons with IMFPs from the EPES experiments of Werner et al. showed a consistency of 8% for energies between 200 and 5000 eV.

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A tip characterizer for atomic force microscopy (AFM) was developed based on the fabrication of multilayer thin films. Comb-shaped line and space (LS) and wedge-shaped knife-edge structures were fabricated on a GaAs substrate. GaAs∕InGaP superlattices were used to control the width of the structures precisely, and selective chemical etching was used to form sharp edges on the nanostructures. The minimum size of the LS structure was designed to be 10nm, and the radius of the knife edge was less than 5nm. These nanostructures were used as a well-defined tip characterizer to measure the shape of a tip on a cantilever from line profiles of AFM images.

Understanding the oxidation of silicon has been an ongoing challenge for many decades. Ozone has recently received considerable attention as an alternative oxidant in the low temperature, damage-free oxidation of silicon. The ozone-grown oxide was also found to exhibit improved interface and electrical characteristics over a conventionally dioxygen-grown oxide. In this review article, we summarize the key findings about this alternative oxidation process. We discuss the different methods of O(3) generation, and the advantages of the ozone-grown Si/SiO(2) interface. An understanding of the growth characteristics is of utmost importance for obtaining control over this alternative oxidation process.

Highly concentrated ͑Ͼ93 vol %͒ ozone (O 3) gas was used to oxidize silicon for obtaining high-quality SiO 2 film at low temperature. Compared to O 2 oxidation, more than 500°C lower temperature oxidation ͑i.e., from 830 to 330°C͒ has been enabled for achieving the same SiO 2 growth rate. A 6 nm SiO 2 film, for example, could be grown at 600°C within 3 min at 900 Pa O 3 atmosphere. The temperature dependence of the oxidation rate is relatively low, giving an activation energy for the parabolic rate constant of 0.32 eV. Furthermore, a 400°C grown SiO 2 film was found to have satisfactory electrical properties with a small interface trap density (5ϫ10 10 cm Ϫ2 /eV) and large breakdown field ͑14 MV/cm͒.

Ultra fine oxidized titanium (Ti) lines 18 nm wide and 3 nm high have been formed on the surface of a 4 nm Ti layer on a SiO2/Si substrate using the scanning tunneling microscope [STM] tip as a selective anodization electrode. The dependence of the size of the oxidized titanium line on the various parameters is investigated. The formed oxidized titanium line has resistivity of 2×104 ohm cm, which is a value seven orders of magnitude higher than that of the deposited Ti layer. The oxidized Ti line is used in the planar type metal-insulator-metal [MIM] diode, and works as an energy barrier for the electron. The energy barrier height of the oxidized Ti line is found to be δE g=0.25 eV.

Recent efforts to achieve global standardization of scanning probe microscopy (SPM) including noncontact atomic force microscopy (NC-AFM), especially through the International Organization for Standardization (ISO) and related research, are surveyed. Since the unification of terminology for SPM is a prerequisite for standardization, it should have the first priority, followed by the unification of data management and treatment, which will enable access to and processing of SPM data collected by different types of instrument. Among the various SPM analytical methods, the dimensional metrology of SPM is regarded to be the first priority for standardization. This requires solving two basic problems: calibrating the x, y, and z coordinate axes with traceability to the SI unit of length, and eliminating the morphological artefacts caused by the shape of the probe tip. Pre-standardization efforts on restoring distorted images and characterizing the tip shape during use are discussed.

Articles you may be interested inNeutralization of space charge on high-current low-energy ion beam by low-energy electrons supplied from silicon based field emitter arrays AIP Conf.Investigation of a rf inductively coupled plasma ion source capable of highly uniform and collimated ion-beam generation Rev. Sci. Instrum. 77, 03B515 (2006); 10.1063/1.2172349Experimental study of electron-and ion-beam properties on the BNL electron-beam ion source and comparison with theoretical models Rev. Sci. Instrum. 77, 03A910 (2006); 10.1063/1.2149377 Current research and development topics on gas cluster ion-beam processesTetrairidium dodecacarbonyl, Ir 4 ͑CO͒ 12 , is a metal cluster complex which has a molecular weight of 1104.9. Using a metal-cluster-complex ion source, it has been demonstrated that stable ion beams of Ir 4 ͑CO͒ 7 + were produced. Energy dependence of sputtering yield of silicon bombarded with Ir 4 ͑CO͒ 7 + ions was investigated at a beam energy from 2 to 10 keV at normal incidence. Experimental results showed that the sputtering yield varied substantially with beam energy. The sputtering yield at 10 keV was higher than that with SF 5 + or Ar + ions by a factor of 3-24, whereas the sputtering yield at 3 keV was lower than that with Ar + ions. In the case of 2 keV, deposition was found to occur. The substantial variation in the sputtering yields was examined using empirical equations for calculating sputtering yields. It was shown that the high sputtering yield at 10 keV would be due to what is called "nonlinear effect" unique to complex-projectile bombardment. It was also indicated that the substantial variation in the sputtering yield would result from lower kinetic energies of each atom constituting the cluster ions. Further, the deposition was explained by considering changes in surface properties caused by the irradiation of the cluster ions.