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D'Alessandro V.,University of Naples Federico II | La Spina L.,Iszgro Diodes BV | Nanver L.K.,Technical University of Delft | Rinaldi N.,University of Naples Federico II
IEEE Transactions on Electron Devices | Year: 2011

An extensive experimental and theoretical analysis of bipolar differential pairs subject to radical electrothermal feedback is presented. Measurements demonstrate that considerable thermally-induced degradation of circuit characteristics may occur, eventually turning into the full disappearance of a linear region, which is replaced by a hysteresis behavior under voltage-controlled conditions. An analytical model is derived for a simple yet reliable prediction of the distortion of I-V curves. A more elaborated circuit approach is employed to accurately quantify the concurrent destabilizing action of electrothermal and impact ionization effects, as well as to evaluate the impact of layout asymmetries and examine the beneficial influence of emitter degeneration resistors. Simulation results are found to compare favorably with experiments performed on silicon-on-glass test structures with various layouts and isolation schemes, from which the benefits of thermally coupling the two devices become evident. © 2011 IEEE. Source


La Spina L.,Iszgro Diodes BV | D'Alessandro V.,University of Naples Federico II | Russo S.,University of Naples Federico II | Nanver L.K.,Technical University of Delft
IEEE Transactions on Electron Devices | Year: 2010

In this paper, design guidelines are provided to improve the thermal stability of three- and four-finger bipolar transistors. Experiments and simulations are first performed on silicon-on-glass (SOG) three-finger bipolar junction transistors (BJTs) with self-heating and mutual thermal resistances varying in a large range of values, depending on the silicon area, presence of heat spreaders, isolation, and distance between fingers. To avoid strong asymmetries between the mutual thermal resistances of two adjacent fingers as compared to nonadjacent fingers, a "hexagonal" topography is proposed. It is demonstrated that, due to the nature of this solution, the onset of thermal instability can be shifted to a higher value of dissipated power. The key role of metal lines and bondpads in fully isolated devices is also highlighted. Subsequently, the electrothermal behavior of SOG four-finger BJTs is investigated and the thermally induced current nonuniformity over the individual fingers is experimentally monitored for the first time. Thermal-only and electrothermal simulations are employed to conceive and analyze more thermally robust layout topographies, referred to here as "rhombus" and "square." © 2006 IEEE. Source


Spirito M.,Technical University of Delft | Galatro L.,Technical University of Delft | Lorito G.,Iszgro Diodes BV | Zoumpoulidis T.,Iszgro Diodes BV | And 2 more authors.
86th ARFTG Microwave Measurement Conference: Microwave Measurements with Applications to Bioengineering and Biomedicine, ARFTG 2015 | Year: 2015

In this contribution we analyze the accuracy improvements of Reciprocal SOL planar calibrations when employing full-wave EM simulation to extract the standard's models. The calibration accuracy is benchmarked with the conventional (polynomial fit) standard definitions as well as with calibration techniques employing standards with partially-unknown parameters, as the LRM. Moreover, an outlook at a technology based on integrated circuit fabrication, employing fused silica substrates is described in terms of the achievable spread of its conductive and resistive layers. Such technology, in combination with the proposed EM modelling of the standards would allow to reduce the residual errors of planar calibrations. © 2015 IEEE. Source


Borrielli A.,CNR Institute of Materials for Electronics and Magnetism | Borrielli A.,National Institute of Nuclear Physics, Italy | Bonaldi M.,CNR Institute of Materials for Electronics and Magnetism | Bonaldi M.,National Institute of Nuclear Physics, Italy | And 21 more authors.
Microsystem Technologies | Year: 2014

The interaction of the radiation pressure with micro-mechanical oscillators is earning a growing interest for its wide-range applications and for fundamental research. In this contribution we describe the fabrication of a family of opto-mechanical devices specifically designed to ease the detection of ponderomotive squeezing and of entanglement between macroscopic objects and light. These phenomena are not easily observed, due to the overwhelming effects of classical noise sources of thermal origin with respect to the weak quantum fluctuations of the radiation pressure. A low thermal noise background is required, together with a weak interaction between the micro-mirror and this background (i.e. high mechanical quality factors). In the development of our opto-mechanical devices, we heve explored an approach focused on relatively thick silicon oscillators with high reflectivity coating. The relatively high mass is compensated by the capability to manage high power at low temperatures, owing to a favourable geometric factor (thicker connectors) and the excellent thermal conductivity of silicon crystals at cryogenic temperature. We have measured at cryogenic temperatures mechanical quality factors up to 10 5 in a micro-oscillator designed to reduce as much as possible the strain in the coating layer and the consequent energy dissipation. This design improves an approach applied in micro-mirror and micro-cantilevers, where the coated surface is reduced as much as possible to improve the quality factor. The deposition of the highly reflective coating layer has been carefully integrated in the micro-machining process to preserve its low optical losses. © 2014 Springer-Verlag Berlin Heidelberg. Source

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