This PDF file contains the front matter associated with SPIE Proceedings Volume 6591, including the Title Page, Copyright information, Table of Contents, Introduction (if any), and the Conference Committee listing.

The Research European Programmes have paid attention to the area of microsystems since the early 90's when the Research was focused on Micro-Electro-Mechanical Systems. Since then the interest has grown into an area of Microsystems and Micro Nano Technology for a wide set of applications in which the multidiscipline and the convergence of technologies play an important role. Systems combining sensing, processing and actuating are increasingly complex involving different disciplines and integrating different technologies, and making the field of Microsystems technology expands to the field of 'Smart Integrated Systems'. Today the attention is focused in the increasing complexity and miniaturization of the systems, networking capabilities and autonomy. The recently launched 7th Framework Programme and the coordination of national or regional research initiatives will help to realise the research agenda for this strategic field for Europe. This paper will give some results of ongoing initiatives, some visions and an outlook for the future with focus in micro and nanosytems.

In recent years the standard lithography reached its limits due to the diffraction effects encountered and the necessary complexity of compatible masks and projection optics. The restrictions on wavelength, in combination with high process and equipment costs make low cost, simple imprinting techniques competitive with next generation lithography methods. There are several Nanoimprint Lithography (NIL) techniques which can be categorized depending on the process parameters and the imprinting method - either step & repeat or full wafer imprinting. A variety of potential applications has been demonstrated using NIL (e.g. SAW devices, vias and contact layers with dual damascene imprinting process, Bragg structures, patterned media) [1,2]. In this work UV-NIL has been selected for the fabrication process of 3D-photonic crystals. Results with up to three layers will be demonstrated.

One of the rapidly advancing femtosecond laser technologies is three-dimensional micro- and nanostructuring by two-photon polymerization (2PP) technique. This technique allows the fabrication of any computer-generated 3D structure by direct laser "recording" into the volume of a photosensitive material. Because of the threshold behavior and nonlinear nature of the 2PP process, a resolution beyond the diffraction limit can be realized by controlling the laser pulse energy and number of applied pulses. Many different applications of 2PP technique are discussed.

The ability to pattern materials in three dimensions is critical for several emerging technologies, including photonics, μfluidics, MEMS, and biomaterials. Electrospinning allows one to functionalized and rapidly fabricate materials in complex three-dimensional shapes without the need for expensive tooling, dies, or lithographic masks. Here, recent advances in functionalization techniques are reviewed with an emphasis on the push toward patterning finer feature sizes. Effects of material and process parameters on the diameter of electrospun Poly Ethylene Oxide (PEO) fibers were experimentally investigated. Experiments were conducted at the settings of solution flow rate, voltage and the collector distance. It also imparted the evaluation of the significance of each parameter on the resultant fiber diameter. All the factors were found statistically significant in the production of nanoscale fibers. Opportunities and challenges associated with electrospinning of polyacrylonitrile fibers are also highlighted.

Subwavelength dielectric and metallic gratings embedded in vacuum can act as highly-resonant spectral filters. We review the theoretical principles for the design of symmetric dielectric and metal gratings to conceive efficient optical filters in the mid and far infrared range, and we show how both resonance width and resonance wavelength can be tuned. We describe an original process for the fabrication of free-standing SiC gratings, and we present the first samples obtained with 10 &mgr;m period. Experimental angularly resolved transmission spectra show evidences of their filtering properties.

A study of the non-linear optical properties of Si-nc embedded in SiO₂ has been performed by using the z-scan method in the nanosecond and femtosecond ranges. Substoichiometric SiO_x films were grown by plasma-enhanced chemical-vapor deposition (PECVD) on silica substrates for Si excesses up to 24 at. %. An annealing at 1250 °C for 1 hour was performed in order to precipitate Si-nc, as shown by EFTEM images. Z-scan results have shown that, by using 5-ns pulses, the non-linear process is ruled by thermal effects and only a negative contribution can be observed in the non-linear refractive index, with typical values around -10^-10 cm²/W. On the other hand, femtosecond excitation has revealed a pure electronic contribution to the nonlinear refractive index, obtaining values in the order of 10^-12 cm²/W. Simulations of heat propagation have shown that the onset of the temperature rise is delayed more than half pulse-width respect to the starting edge of the excitation. A maximum temperature increase of ΔT = 123.1 °C has been found after 3.5 ns of the laser pulse maximum. In order to minimize the thermal contribution to the z-scan transmittance and extract the electronic part, the sample response has been analyzed during the first few nanoseconds. By this method we found a reduction of 20 % in the thermal effects. So that, shorter pulses have to be used to obtain just pure electronic non-linearities.

The electrical activity of nitrogen related defects are investigated in ultra-nanocrystalline diamond (UNCD) films achieved using different N₂% in the gas phase by transient photocurrent technique at λ = 193 nm, and by steady state photocurrent measurements in the photon energy range 1-6 eV. In undoped UNCD films, spectrally resolved photocurrent measurements reveal a threshold at about 1 eV, related to the absorption of non diamond carbon phases, followed by a monotonic increase by more than one order of magnitude up to about the diamond energy gap, where a steep rise occurs due to band to band transitions. In nitrogen doped UNCD films a clear onset of the spectral photocurrent signal is hardly detectable, although an apparent shift towards higher energies is evidenced, in agreement with a possible nitrogen induced Fermi level shift upward in the band gap. The main N-related feature of the spectra is however a sharp peak at about 4 eV, which is also observed in polycrystalline diamond films grown in a nitrogen rich gas mixture, particularly close to the boundary of the deposition area. On the other hand, photocurrent pulse shape analysis gives carrier lifetime values in the 6-10 ns range, almost independent of nitrogen content. Instead, N-related defects appear mainly responsible for trapping processes, which slow down carrier transport and give rise to long transit times. Such results are discussed in terms of photoionization of N-related defects formed in the non diamond carbon phase.

The electron transport properties of different Silicon on Insulator (SOI) devices have been studied. We have considered two type of semiconductor structures: i) quantum-well SOI structures and ii) quantum-wire devices. In the first group, Qwell-based devices, the electron mobility in double-gate SOI devices as the silicon thickness, decreases was compared with the mobility in Single-Gate SOI structures. Thus, we determined the existence of a range of silicon layer thicknesses in which electron mobility in DGSOI inversion layers is significantly improved as compared to bulk-silicon or SGSOI inversion layers, due to the volume inversion effect. With regard to QWire-based devices, we have analyzed the phonon-limited mobility in silicon quantum wires by means of a one-particle Monte Carlo simulator. It has been observed that the increasing of the phonon scattering produces a noticeable reduction of the electron mobility observed when the device dimensions are reduced. Therefore, we have observed that the transition from a 2D to a 1D electron gas produces a degradation of the electron transport properties.

Optical spectroscopic characterization of silica layers containing silicon nanocrystals (Si-nc) is described in detail. Red- NIR photoluminescence (PL) is studied and correlations of the PL with optical and structural properties are analyzed. The surface mechanism of PL involving Si=O bonds is supported by our results. Wavelength-selective optical waveguiding by Si-nc/SiO₂ layers is studied. The found spectral filtering allows optical properties of Si-nc/SiO₂ layers to be measured. Laser-induced thermal effects on structural and optical properties of free-standing Si-nc/SiO₂ films are reported. The obtained results suggest very efficient Si-SiO₂ phase separation by intense laser light. Laser-controlled stress of Si-nc in silica is demonstrated. The laser manipulations with Si-nc stress offer an approach to Si-nc memory with an extremely long retention time, which can be written, read, and erased by optical means.

Porous SnO₂ nanoribbons, with their width and thickness of around 20&mgr;m and 20nm, respectively, have been fabricated from the metallo-organic dimethyldineodecanoate tin using electrospinning and thermal decomposition techniques. The electrical conductance of one synthesized single ribbon has been measured using the two-probe method in atmosphere following a cycle of heating from 300 to 660K and subsequent cooling from 660K to 300K. During the heating, the conductance, G is not so sensitive to the temperature below 380K and, above that, follows an Arrhenius relation with a thermal activation energy of 0.918±0.004 eV until 660K; upon cooling, G follows the same Arrhenius relation until 570K and, below that, observes another Arrhenius relation with its activation energy decreasing to 0.259±0.006eV down to 300K. After a cycle of heating and cooling, G returns to a value higher than its initial one. The Arrhenius relations are attributed to the surface adsorption and desorption of moisture and oxygen, and the G hysteresis between 300 and 380K is attributed to the partial replacement of adsorbed oxygen by moisture because of the porous nature of the surface.

Tin oxide is a binary semiconductor with a wide band gap (E_g = 3.6 eV at 300 K) and has been used, mostly in the form of thin films, as the active element in gas sensing applications. As a fiber it is expected to have improved sensitivity as the surface-to-volume ratio increases. The authors fabricated undoped tin oxide and antimony-doped tin oxide nanofibers using electrospinning and metallorganic decomposition techniques. The precursor solution for the undoped fibers was based on a tin (IV) chloride and a viscous solution based on poly(ethylene oxide) (PEO). The antimonydoped precursor solution had an additional antimony trichloride solution made from isopropanol to obtain a Sb concentration of 1.5 %. To study the sensitivity of the fibers to gas exposure, both single nanofibers and nanofiber mats were electrospun onto Si/SiO₂ wafers. The changes in the nanofiber resistance with exposure and removal of methanol were measured as a function of time and gas concentration. In both configurations, the undoped nanofibers show higher sensitiviy to the presence and removal of methanol. Both the undoped and antimony-doped tin oxide single nanofibers show faster response times than the nanofiber mats. Of all the configurations tested, the antimony-doped single fiber gives more stable and faster response.

In this paper we investigate an in situ measurement of polymer and lithographic resist film mechanical properties on a silicon substrate, with a Dynamical Mechanical Analysis tool (DMA). This technique allows the measure of the glass transition temperature (Tg) of the resist film (thickness range: several μm to few nm) and its elastic and viscous modulus variations with a high precision and reproducibility. Indeed, DMA appears to be more sensitive than other thermal analysis methods like Differential Scanning Calorimetry (DSC), to monitor Tg variations induced by film thickness reduction. First we will discuss the performance of the tool and present the variations of the glass transition temperature of a PMMA (PolyMethylMethAcrylate) layer as a function of its thickness: we observe a shift towards higher temperatures up to 30°C when the film thickness decreases from one micrometer to 10nm. This behavior highlights the importance of surface properties versus bulk. We will also discuss the interest of the DMA technique applied to more complex chemistries, as it is the case for lithographic resist formulations, i.e. a blend of polymer with grafted functionalities, photoactive compounds and various additives. We successfully applied this technique to characterize different resist film thicknesses and we observed the effect of the thickness on the thermal events. Such kind of change is important to take into account in the optimization of material performance for thin film applications. This material understanding allows to better define the process conditions and can be applied to different microelectronic topics such as: thermal flow treatment of positive tone photo resists, hot-embossing nanoimprint, cross linking reactions with negative tone resists or so called "hardening" processes.

Diamond like-carbon films were fabricated by pulsed laser ablation of a liquid target (vacuum oil) in a very small (volume below 1 cm³) vacuum chamber, where the film was deposited onto the inner surface of the chamber window. The synthesis was carried out at room temperature using 248 nm KrF excimer laser. The sp³ hybridization carbon formation was additionally promoted by gaseous H₂O₂ flow through the reaction chamber. Deposited diamond-like carbon films were characterized by Raman scattering spectroscopy, optical and atomic force microscopy. The results indicated that higher sp³ content was present in the film areas exposed to the laser irradiation during the deposition. The surface roughness of these areas was lower compared with that of the non-irradiated areas. Optical microscopy observations indicated that the films had interference-colored regions on laser irradiated areas. These colored regions were significantly different from their surroundings, which were grey or brown. Thus, the interferencecolored regions have very wide band gap (&Dgr;E > 3 eV) and accordingly, high sp³ hybridized carbon content.

By the use of a chemical vapour deposition technique a series of metal wires (W, Ta, Steel ) with differently shaped tips have been coated by arrays of single wall carbon nanotubes (SWNT). The field emission properties of the SWNT deposits have been measured by a home made apparatus working in medium vacuum (10^-6- 10^-7 mbar) and the SWNT-coated wires have been used to fabricate tiny electron sources for X-ray tubes. To check the efficiency of the nanotube coated wires for X-ray generation has, a prototype X-ray tube has been designed and fabricated. The X-ray tube works at pressures about 10^-6 mbar. The target ( Al film) is disposed on a hole in the stainless steel sheath: this configuration makes unnecessary the usual Be window and moreover allows us to use low accelerating potentials (< 6 kV).