Dariusz Szmigiel

Decomposition of ammonia over potassium promoted ruthenium catalyst supported on carbon

The rate of NH3 decomposition has been measured over the K-Ru/C catalyst, the studies being accompanied by the N2-TPD experiment. The catalyst proved to be extraordinarily active in ammonia decomposition. The TOF values over K-Ru/C were almost 103 times higher than those for the triply promoted magnetite, both referred to the nitrogen chemisorption. The rate of nitrogen desorption was found to be significantly lower than the rate of NH3 decomposition under the comparable conditions. It is suggested that the adsorbate–adsorbate interaction is responsible for the higher rate of the latter. The modelling based on the Langmuir–Hinshelwood kinetics shows the coverage of Nad in high pressure NH3 synthesis to be very small.

Microfabricated resistive high-sensitivity nanoprobe for scanning thermal microscopy

In this article, a novel microfabricated thermoresistive scanning thermal microscopy probe is presented. It is a V-shaped silicon nitride cantilever with platinum lines and a sharp off-plane nanotip. The cantilever fabrication sequence incorporates standard complementary metal oxide semiconductor technology processes and therefore provides high reproducibility, while the tip is additionally processed by focused ion beam, enabling high-sensitivity and high-resolution thermal sensing. The nanoprobe is designed for scanning thermal microscopes, operating in standard atomic force microscope setup with an optical detection system. The measurement setup, which is also presented, takes advantage of the four-point design of the probe by inclusion of a Thomson bridge and a modified Wheatstone bridge measurement electronics.In this article, a novel microfabricated thermoresistive scanning thermal microscopy probe is presented. It is a V-shaped silicon nitride cantilever with platinum lines and a sharp off-plane nanotip. The cantilever fabrication sequence incorporates standard complementary metal oxide semiconductor technology processes and therefore provides high reproducibility, while the tip is additionally processed by focused ion beam, enabling high-sensitivity and high-resolution thermal sensing. The nanoprobe is designed for scanning thermal microscopes, operating in standard atomic force microscope setup with an optical detection system. The measurement setup, which is also presented, takes advantage of the four-point design of the probe by inclusion of a Thomson bridge and a modified Wheatstone bridge measurement electronics.

Potassium-Promoted Carbon-Based Iron Catalyst for Ammonia Synthesis. Effect of Fe Dispersion

Potassium-promoted iron catalysts supported on thermally modified, partly graphitized carbon were studied in the ammonia synthesis reaction. Iron nitrate was used as a precursor of the active phase and KOH or KNO3 were used as promoters. The kinetic studies of NH3 synthesis were carried out in a differential reactor under 63 bar and 90 bar pressure. Hydrogen chemisorption, X-ray diffraction and transmission electron microscopy experiments were performed to determine the dispersion of iron in the specimens. All the K+–Fe/C catalysts proved to be sensitive to ammonia, the NH3 partial pressure dependencies of their reaction rates being close to that of the commercial magnetite catalyst (KM I, H. Topsoe). The catalytic properties of the promoted Fe particles on carbon were shown to be dependent upon the iron dispersion, i.e. smaller particles exhibited higher turnover frequency in NH3 synthesis. It is suggested that either small Fe crystallites expose more highly active sites, e.g. C-7 (B-5) or the promotion of small crystallites by the alkali is more efficient.

Design and properties of silicon charged-particle detectors developed at the Institute of Electron Technology (ITE).

The paper discusses the design of charged-particle detectors commissioned and developed at the Institute of Electron Technology (ITE) in collaboration with foreign partners, used in international research on transactinide elements and to build personal radiation protection devices in Germany. Properties of these detectors and the results obtained using the devices are also presented. The design of the following epiplanar detector structures is discussed: ♦ 64-element chromatographic arrays for the COMPACT (Cryo On-line Multidetector for Physics And Chemistry of Transactinides) detection system used at the GSI Helmholtzzentrum für Schwerionenforschung in Darmstadt (GSI) for research on Hassium, Copernicium and Flerovium, as well as elements 119 and 120, ♦ 2-element flow detectors for the COLD (Cryo On-Line Detector) system used for research on Copernicium and Flerovium at the Joint Institute for Nuclear Research, Dubna, ♦ detectors for a radon exposimeter and sensors for a neutron dosimeter developed at the Institut für Strahlenschutz, Helmholtz Zentrum München. The design of planar detectors – single-sided and double-sided strip detectors for the Focal Plane Detector Box used at GSI for research on Flerovium and elements 119 and 120 is also discussed.

Polysiloxane Coatings on Biomedical Micro Devices: Plasma Etching and Properties of Protection Layer

We investigated the plasma etching of polysiloxane intended for use in cochlear implants as a protection layer. The processing was performed using fluorine-based chemistry ionized in RIE (Reactive Ion Etching) or ICP (Inductively Coupled Plasma) discharge. The effect of temperature on polysiloxane etch rate and the resulting surface morphology was examined. XPS was employed to determine chemical changes induced by plasma treatment. The cytotoxicity on a cell line was observed in order to estimate suitability of plasma processed silicone elastomer for use in biomedical applications. This paper presents the selected results, which reveals how the polysiloxane surface properties can change depending upon plasma treatment conditions. Exemplary micro devices encapsulated in plasma treated silicone elastomer are also shown.

A simple method for characterization of MOSFET serial resistance asymmetry

A method for a direct extraction of individual serial resistances of MOSFET source/drain electrodes is presented. It is based on the device I-V characteristics in a saturation range measured for two device configurations inverted with respect to source and drain electrodes. A threshold voltage necessary for the saturation range modeling is determined from the non-saturation range I-V characteristics. Based on the measurement data determined for the SOI MOSFETs fabricated in ITE the proposed method has been compared with other techniques.

Dedicated MEMS-based test structure for 3D SiP interconnects reliability investigation

This paper discusses important aspects of development process of dedicated test vehicles designed for investigation on thin metal layers reliability by a novel Accelerated Thermo-Mechanical Ageing method (ATMA) [1] being developed now. It is an ongoing research report presenting current state of the R&D works, investigation on ATMA usefulness and its applicability to interconnect reliability evaluation.

MOSFETs in the VeSTIC process - fabrication and characterization

A method for fabrication of VeSFETs, three-dimensional fin-type MOS transistors is presented. The VeSTIC process was developed and experimentally implemented in ITE. The test devics were manufactured, and their electrical characteristics were measured. Methods for extraction of a set of the VeSFET physical parameters are proposed based on the device compact model. The flat-band voltage, mobility and radius of the slit curvature are extracted from the I–V characteristics of a single device.

From Simulation to Manufacturing of Piezoelectric Micromachined AlN Membrane

The ongoing race in microelectronics results in increasing complexity of micro-electro-mechanical systems (MEMS) being developed. Recently, a growing interest is observed in piezoelectric layers and their application in MEMS transducers and sensors. Piezoelectric transducers move due to voltage excitation and usually have simple mechanical structure, with a sandwich of layers among which a piezoelectric layer occurs.

16-element photodiode array for the angular microdeflection detector and for stabilization of a laser radiation direction

In this paper, the design and technology of two types of 16-element photodiode arrays is described. The arrays were developed by the ITE and are to be used in detection of microdeflection of laser radiation at the Institute of Metrology and Biomedical Engineering in the Faculty of Mechatronics of Warsaw University of Technology. The electrical and photoelectrical parameters of the arrays are presented.