Wolfgang Henschel

Study of a high contrast process for hydrogen silsesquioxane as a negative tone electron beam resist

An extensive study of parameters pertinent to electron beam lithography with hydrogen silsesquioxane as a negative tone electron beam resist is presented. With higher developer concentrations contrast and reproducibility are improved significantly at the expense of lower sensitivity. In a similar way extended delays between the baking and exposure degrade the sensitivity but increase the contrast. In contrast, at higher baking temperatures the sensitivity is improved but the contrast and reproducibility deteriorate. These results are discussed within a microscopic model. Contrast values as high as 10 and good reproducibility have been obtained with a developer concentration of 25% tetramethyl ammonium hydroxide and a baking temperature of 90 °C. With these optimal parameters an experimental lithographic pattern of 50 nm lines and spaces could be resolved in 220 nm thick HSQ resist film exposed at 50 keV.

Large scale ultraviolet-based nanoimprint lithography

Limits in resolution and accuracy of large scale ultraviolet (UV)-based nanoimprint lithography using rigid quartz molds and spin coated UV curable resists are presented. The resolution and precisi ...

Influence of channel width on n - and p -type nano-wire-MOSFETs on silicon on insulator substrate

The fabrication and characterization of nanoscale n- and p-type multi-wire metal-oxide semiconductor field effect transistors (MOSFETs) with a triple gate stracture on silicon-on-insulator material (SOI) is described in this paper. Experimental results are compared to simulation with special emphasis on the influence of channel width on the subthreshold behavior. Experiment and simulation show that the threshold voltage depends strongly on the wire width at dimensions below 100 nm. It is further shown that the transition from partial to full channel depletion is dependent on channel geometry. Finally, an increased on-current per chip area is demonstrated for triple-gate SOI MOSFETs compared to planar SOI devices.

Characterization and operation of a mechanically actuated silicon microgripper

Since the manipulation of biological objects is usually performed in a life-sustaining environment, electrical fields or thermal gradients through the liquid may cause perturbations. The authors present a microgripper fabricated in silicon by a combination of bulk and surface micromachining processes that exhibits several advantages compared to previous reports. In order to avoid any possible perturbation caused by electrical fields, their microgripper is mechanically actuated. The complete system including the microgripper, a piezoactuator, and a nanomanipulator is described in detail together with manipulation of micrometer sized glass spheres.

Impact of supercritical CO2 drying on roughness of hydrogen silsesquioxane e-beam resist

Surface roughness (SR) and, especially, the closely related line-edge roughness (LER) of nanostructures are important issues in advanced lithography. In this study, the origin of surface roughness ...

Contactless capturing of particles in liquid using pulsed alternating dielectrophoresis

Dielectrophoresis is an effective method for manipulation of particles in a medium, which can be achieved by applying electrical potentials to appropriately arranged electrodes. In the case of positive dielectrophoresis, the particles will move to regions of strong electric field and be captured at the edge or the surface of the electrodes, usually. The drawback thereby is that the particles may attach to the electrodes, leading to unwanted side effects. Negative dielectrophoresis moves them away from high field regions. In this article, the authors present a new method for contactless capturing of particles by using pulsed alternating dielectrophoresis. A signal sequence consisting of two pulsed ac voltages of different frequencies is applied to the electrodes. Each of them generates either positive or negative dielectrophoresis, respectively. With appropriate settings of dwell times and amplitudes, the particles are attracted toward the electrodes without attaching to them. Furthermore, the average dist...

Fabrication of 12 nm electrically variable shallow junction metal–oxide–semiconductor field effect transistors on silicon on insulator substrates

Electrically variable shallow junction metal–oxide–semiconductor field effect transistors on silicon on insulator have been fabricated to evaluate the suitability of fabrication processes on a nanoscale. In addition, the limits of scalability have been explored reducing gate lengths down to 12 nm. Specific attention has been paid to the overlay accuracy as required for the fabrication of these double gate structures. The superior quality of hydrogen silsesquioxane (HSQ) as electron beam resist and as mask material is demonstrated. The transistor fabricated exhibits extremely low leakage currents and relatively high on currents. The 8 orders of magnitude difference between the on and off states demonstrates conclusively large potentials for metal–oxide–semiconductor structures with critical dimensions in the 10 nm regime.