In vivo measurements with robust silicon-based multielectrode arrays with extreme shaft lengths

In this paper, manufacturing and in vivo testing of extreme-long Si-based neural microelectrode arrays are presented. Probes with different shaft lengths (15–70 mm) are formed by deep reactive ion etching and have been equipped with platinum electrodes of various configurations. In vivo measurements on rats indicate good mechanical stability, robust implantation, and targeting capability. High-quality signals have been recorded from different locations of the cerebrum of the rodents. The accompanied tissue damage is characterized by histology

Membrane Platforms for Sensors

AbstractIn the past half century the IC technology could produce an unprecedented growth and penetration into all segments of our daily life due to the achieved extreme productivity and reliability by using well established and continuously refined processing platforms. This uninterrupted trend continued also with the advent of the More than Moore-type MEMS technology allowing the combination of the signal processing capability of the mature IC technology with the exploitation of mechanical, thermal, optical properties of the materials used in IC technology in different sensing and actuation purposes. Mass producibility by monolithic integration required here also the development of appropriate unified set of techniques for the various applications, i.e. sort of standardised platforms to explore.In this paper we focus on the development of bulk micromachined membrane platforms, being exploited in such applications. At the same time this summary also offers a “case study”, a retrospective review of the development of integrable sensors from pressure measurement to nanopore-type, label-free biosensing at the Institute of Technical Physics & Materials Science - MFA, Budapest

Millimeter wave detection by thermopile antenna

AbstractIn this paper a novel MEMS thermopile structure is proposed, which consist of linearly arranged p- and n- type polysilicon strips instead of the conventional loop-like configuration. It is shown that these devices sense the millimeter wave radiation beyond the infrared. The polarity and frequency dependence of the sensitivity prove that these strips behave as absorbing antennas towards the microwave/millimeter wave radiation. The induced current is calculated having a maximum in the geometrical center of the antenna, exactly at the position where the hot end of the thermopair is located. The measured responsitivities to direct heating, infrared radiation, 13 GHz microwave radiation and 100 GHz millimeter-wave radiation are presented

Energy Harvesting Powered Wireless Vibration Analyser

In this work we present a complex, wireless, ambient energy powered and easy-to-use solution for vibration analysis. It is designed to incorporate the latest commercial technologies and achievements in the field of energy harvesting and wireless sensor networks with an emphasis on energy efficient spectrum estimation algorithms for embedded systems. This solution is realized on a small printed circuit board and contains all the necessary circuit components for hybrid energy harvesting; acceleration sensing; data acquisition, storing and analysis; and wireless communication. The on-board microcontroller was programmed to choose the most energy-efficient data handling algorithm (direct transfer or embedded analysis) based on the weighed combination of user settings and ambient energy. We tested and calibrated our system in laboratory environment with reference sensors, as well as in an engine room, simulating practical applications

Sensitivity tuning of A 3-axial piezoresistive force sensor

Design and development of a Si based full membrane piezoresistive 3D force sensor is presented in this paper. Four piezoresistors are formed by ion implantation on the back side of a thin Si membrane, while on the front side a 380 μm high Si mesa is produced by subtractive dry etching (deep reactive ion etching). The external force is applied on the top of the mesa. The applied force vector, i.e. its normal and shear force components are determined by combining the responses of the four piezoresistors. The effect of different parameters – the shape and thickness of the membrane, the cross section of the mesa – on the sensitivity of the sensor is analyzed systematically by finite element methods. Comparison of the characteristics of the different sensor designs obtained from simulations and from experimental measurements is also presented

Novel method for the production of SiC micro and nanopatterns

In this paper we report on a novel, large area method to produce SiC nano- and micro patterns at room temperature where the compound and pattern formation happens in one step. We have previously demonstrated that SiC can be produced by noble gas irradiation of a Si/C multilayer system utilizing the ion beam mixing (IBM) taking place at the interfaces. Here we show that by applying IBM in samples masked in any desired way patterned SiC surfaces, micro and nanostructures, result. Two different masking layers were applied to demonstrate the capabilities of the method; a Langmuir-Blodgett (LB) film of 590 nm silica nanoparticles and a lithographic grid, of 2 μm periodicity, mounted to the surface of a Si/C multilayer system. The systems were irradiated by Xe+ ions of 120 keV. The samples before and after IBM have been analyzed by AFM, SEM and AES depth profiling, proving that patterning occurred: the non-covered areas became SiC rich regions, while the covered areas remained untouched. As a possible application for the patterned samples, the gold-coated LB patterned nanostructure was used for surface enhanced Raman spectroscopic detection of an organic dye molecule (R6G) demonstrating the efficiency of IBM for producing SERS substrates consisting of a very stable compound like SiC

Ionsugaras módszerek a fizikai nanotechnológiában (IONNANO) = Ion beam modifications in near-to-physics nanotechnology

Témavezeto: Gyulai József - SiO2 mátrixban Si, Pd-Pt és SiC, valamint SiC-ben gyémánt nanokristályokat állítottunk elő és minősítettünk. - Szén nanocsöveket Ar+ ionokkal besugározva, ponthibákat, kiemelkedő klasztereket és szuperstrukturákat figyeltünk meg. - Ellipszometriával mértük a szilíciumkarbidban ionimplantációval létrejövő roncsoltságot. - Az ionsugaras kutatásaink alapján eljárást fejlesztettünk ki, amellyel külön-külön detektálható a Si-, valamint a C-alrács károsodása. - Ezzel sikerült megbecsülni a He ion c-tengelyi csatorna irányú és random irányú energiaveszteség arányát. - Optikai modelleket fejlesztettünk ferroelektromos anyagok mérésére, valamint továbbfejlesztettük a rácskárosodás ellipszometriai modelljét. - Extrém kis energiájú ionok folyamatainak kutatása a porlasztást alkalmazó felületvizsgáló módszerek kvantifikálását célozta: - új ionkeveredési mechanizmust javaslunk birétegekre - Molekula-dinamikai szimulációnkat kiterjesztettük több ion szukcesszív becsapódásának a vizsgálatára a Ti/Pt kettősrétegben. - Súrlódó beesésnél a szén porlasztási sebessége nagyobb, mint a fémeké. - Kerámiák nanoszerkezetének módosítása témában kiemelkedő eredményünknek tartjuk, hogy a világon elsőként nekünk sikerült előállítani karbon nanocső - szilícium-nitrid kompozitot, amelyben a nanocsövek nem degradálódnak a szinterelés során. | Principal investigator: Gyulai József - Nanocrystals were prepared and characterized: Si in SiO2, Pd-Pt, SiC in Si, and diamond in SiC. - Argon ion irradiation of carbon nanotubes resulted in point defects, clusters and superstructures, as detected with atomic resolution AFM. - Ellipsometry proved itself as efficient method to study radiation damage in SiC. - New version of ion beam analysis applied to implanted SiC allowed us to detect the damage of the carbon and silicon sublattice separately - With defects as markers, ratio of channeled to random stopping power of He ions could be deduced. - Optical model was developed for ellipsometry allowing also characterization of ferroelectric (high-k) materials. - Modeling and experimental studies of damaging and sputtering processes at impact of extreme low-energy resulted in better quantification of surface analysis techniques (Auger profiling): - MC simulation of bilayers led us to a new model of ion beam mixing. - MD simulations were extended to multiple ion impact on Ti/Pt bilayers. - Sputtering coefficient of carbon was found (and modeled) to be higher than that of a metal for sputtering at glancing angle incidence. - Nanostructure of ceramic materials, firstly, of Si3N4, resulted in the first Si3N4-carbon nanotube nanocomposite, where the nanotubes will not degrade during high-temperature sintering

Elektromágneses hullámok mesterséges periodikus szerkezetekben = Electromagnetic waves in artificial periodical structures

Pórusos szilícium mintákban egydimenziós fotonikus kristályok állítottunk elő. Az elvégzett mérésekről és a hullámterjedés FDTD modellezéséről megjelent publikációink a közleményjegyzék 4., 7., 8., 11. és 21. tételei. FDTD modellezéssel vizsgáltuk a hullámterjedést kétdimenziós fotonikus kristályokban és beépített hullámvezető hibavonalak mentén. A kétdimenziós számításokról a jegyzék 16., valamint 12., 14., 19 és 20. tételeit közöltük. Előkészületeket tettünk az MTA MFA nanomegmunkáló laborjában, az egybeépített elektronmikroszkóp és fókuszált ionnyaláb alkalmazásával kétdimenziós fotonikus kristályok előállítására. A BME Fizikai Kémia Tanszékének kutatóival együttműködést kezdeményeztünk a Langmuir-Blodgett kísérleti módszer alkalmazására kétdimenziós fotonikus kristályok előállítása céljából. Ez az "önszerveződő maszkolási" eljárás teljesen újszerűnek bizonyult és erre vonatkozó publikációinkat komoly szakirodalmi sikernek tekintjük (a jegyzék 22-28. tételei). A témakör népszerűsítésére vonatkozó publikációink a jegyzék 1., 2., 3., 5. és 13. tételei. Két munkatársunk Japánban kapott 2 éves munkalehetőséget: Szabó Zsolt a 3 dimenziós FDTD módszer programkódjának elkészítésén, Volk János a kétdimenziós fotonikus kristály szerű ZnO szerkezetek előállításán és kísérleti vizsgálatán dolgozik. A beruházási keretből ''Nanocube'' típusú nanométer felbontású pozicionáló berendezést vásároltunk. | One dimensional photonic crystals have been prepared in Porous silicon samples. The experimental observations and the FDTD modeling of wave propagation in such structures have been published as the 4., 7., 8., 11. and 21. items of the publication list. Wave propagation has been studied in two dimensional photonic crystals and along wave-guides built therein using FDTD modeling. Publications on two dimensional structures are the 16., as well as the 12., 14., 19. and 20. items. We have attempted the preparation of two dimensional photonic crystals by applying focused ion beam in the nanofabrication lab of our MTA MFA institute. In cooperation with the Physical Chemistry Depertment of BME (BTU) we have intended to apply the Langmuir-Blodgett technique for the preparation of two dimensional photonic crystals. Asa result the ''self-assembled masking'' procedure proved to be a genuine novelty and our publications of the method are considered as works attracting serious impact (22.-28.items). In several publications we intended to disseminate popularizing information for wider community (1., 2., 3., 5. and 13. items of the list) Two colleagues work in Japan, Zsolt Szabó on coding of three dimensional FDTD modeling, János Volk on preparation and experimental study of periodic ZnO two dimensional structures. We have purchased a "Nanocube" type positioning device of nanometer acccuracy