C. Codreanu

National Institute for Research and Development in Microtechnologies

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V.V.N. Obreja

National Institute for Research and Development in Microtechnologies

Marioara Avram

National Institute for Research and Development in Microtechnologies

Carmen Moldovan

National Institute for Research and Development in Microtechnologies

Bogdan Firtat

National Institute for Research and Development in Microtechnologies

E. Iliescu

Horia Hulubei National Institute for R and D in Physics and Nuclear Engineering

K. Nuttall

University of Liverpool

O. Buiu

National Institute for Research and Development in Microtechnologies

C. Voițincu

National Institute for Research and Development in Microtechnologies

Daniel Necula

École Polytechnique Fédérale de Lausanne

Rodica Iosub

National Institute for Research and Development in Microtechnologies

Cooperative Institutions

National Institute for Research and Development in Microtechnologies

Universitatea Națională de Știință și Tehnologie Politehnica București

University of Bucharest

Centre National de la Recherche Scientifique

Centro Nacional de Microelectrónica

Laboratoire d'Analyse et d'Architecture des Systèmes

University College Cork

Research Institute for Analytical Instrumentation

Université de Toulouse

Institut National des Sciences Appliquées de Toulouse

Author Statistics

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Low cost technology for high frequency bipolar integrated circuits

M. Bădilă C. Codreanu Gheorghe Brezeanu

A new low cost technology for high frequency bipolar circuits is proposed. It upgrades a classical "LISA" (Local Implantation Self Aligned) technology using a 14 masks process. The "basic" npn elementary transistor in the new technology has a 2.2 GHz cutoff frequency, and the parasitic elements in circuits are reduced. The performances of the new technology are verified by means of some demonstrator circuits: a "Gilbert" cell with a bandwidth of 700 MHz, and some broadband, high frequency amplifiers.

Cutoff frequency

Integrated injection logic

10.1109/asdam.1998.730164

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Experimental Drain I-V Characteristics of Power MOS Transistors and the Nature of Reverse Leakage Current of Oxide Passivated PN Junctions

International Semiconductor Conference (2006)

V.V.N. Obreja C. Podaru E. Manea A. Coraci C. Codreanu

Drain electrical characteristics for a 10 A and 400V MOS transistor have been measured and analyzed. At junction temperature as high as 200 degC and above this value, accentuated rise of the drain reverse (blocking) current takes place before the specified voltage of 400 V is reached, due to current leakage at the cells junction edge. Observed constant drain current, attributed to a primary diffusion current component is not undoubted evidence for the location of this current in the junction bulk. Similar behavior is observed when bias voltage below the threshold voltage is applied on the gate. Oxide-passivated junctions from bipolar devices may behave like those from MOSFETs at high temperature

Leakage (economics)

Drain-induced barrier lowering

Power MOSFET

10.1109/smicnd.2006.284004

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Citations (2)

Novel design structure for a dual-drain MOSFET magnetic sensor integrated in SOI

Marioara Avram C. Codreanu Cristian Ravariu

A new MOS magneto-transistor design structure is proposed. The device is intended to be fabricated in SOI-MOSFET technology and has a geometry design based on the traditional concept of dual-drain MOS magneto-transistor. In the present SOI-MOSFET variant, this configuration consists in symmetrically placing the source between gates and drains. To prevent the floating-body effect in SOI structure, a backside gate positively biased is used. Doping levels were chosen from SUPREM technology program simulations and dimensions are chosen to agree with the actually given technology in which this device could be fabricated. The device structure was simulated with PISCES program and the simulation results regarding device performance were compared with some experimental data for similar devices reported in literature.

10.1109/smicnd.2000.889139

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The operation temperature of silicon power thyristors and the blocking leakage current

2004 IEEE 35th Annual Power Electronics Specialists Conference (IEEE Cat. No.04CH37551) (2004)

V.V.N. Obreja C. Codreanu C. Podaru K. Nuttall O. Buiu

Typical experimental blocking I-V characteristics measured from room temperature up to high junction temperature for commercial thyristors available on the market at this time are presented. It is shown that the surface peripheral leakage current is a factor which prevents operation above 125 /spl deg/C. Further reduction of the surface component of the off - state blocking leakage current could enable reliable operation of power thyristors at higher junction temperature of at least 150 /spl deg/C.

Blocking (statistics)

Leakage (economics)

10.1109/pesc.2004.1355310

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Citations (9)

Enzymatic biosensor for insecticides detection

International Semiconductor Conference (2008)

Carmen Moldovan Rodica Iosub Cornel Radu Nita Codreanu Marian Ion

The detection of organophosphoric insecticides, in a simple manner was made using impedimetric enzyme biosensors, which allow determination in sub-micromolar concentration ranges. This type of measurement applies for monitoring of biocatalytic reactions based on irreversible inhibition of the enzyme (acetylcholinesterase). The reaction involves generation of charged species, which leads to a global change in the ionic composition of the tested solution.Our work has been focused on the development of an impedimetric microsensor for direct detection of dichorvos, because this kind of biosensor presents a number of advantages such as: miniaturized electrodes based on gold thin film; easy production using standard microtechnology; low cost; no reference electrode required; no light sensitivity and differential mode measurements possibile allowing elimination of interferences. In addition, dichlorvos is targeted to be detected considering that the commonest poisoning today is due to: Methyl Parathion (metacid), Dichorvos (Nuvan), Zinc Phosphide and Aluminium Phosphide (Celphos). The biosensor with interdigitated electrodes and immobilized acetylcholinesteraze (AChE) measures the impedance of the layer adjacent to the electrode surface. The impedimetric measurement consists of determining the conductivity and capacitance of the solution between two interdigitated electrodes. The chemistry of deposited enzymatic layer (concentration, enzymatic activity measuring, deposition protocol), the immobilization technique for AChE, the fabrication technique and the electrical characteristiques of the enzymatic sensor have been studied. AChE immobilization was performed by ionic adsorption on polyethylenglycol (PEG) bio-polymeric substrate, by including in the gel. The functionalized electrodes deposited with biomaterial were inserted into the microfluidic channels and tested from electrical andmicrofluidic point of view, achieving the micro-bio integration. Insertion of electrolyte plus acetilcholine into the channels leads to activation of the enzyme and the measurements are realized under the strict control of temperature and pH. The response time is about 10 minutes.

10.1109/smicnd.2008.4703353

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Bipolar magnetic microsensor for longitudinal and transversal magnetic fields

Sensors and Actuators A Physical (2005)

Marioara Avram Ciprian Iliescu O. Neagoe Corneliu Voitincu C. Codreanu

Transversal (combinatorics)

Magnetic reactance

10.1016/j.sna.2005.04.010

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I-V reverse characteristic instability of high voltage silicon PN junctions at high temperature

V.V.N. Obreja C. Codreanu C. Podaru

Typical experimental results are presented for silicon (Si) PN junctions with a potential reverse voltage higher than 1000 V, revealing reverse current-voltage (I-V) characteristic instability at temperature higher than 125/spl deg/C. High levels of the reverse current reached on behalf of the surface leakage current cause I-V characteristic instability accompanied by a looping effect when this is displayed by means of a curve tracer. For standard recovery silicon diodes stable I-V characteristics are possible up to 200/spl deg/C if enough reduction in the level of the reverse current is provided. For fast recovery high voltage junctions stable characteristics above 150/spl deg/C have not been found for commercial available devices. Although the surface current component is the secondary one for these diodes, it may have some contribution to characteristic instability.

Reverse leakage current

Reverse bias

Leakage (economics)

10.1109/smicnd.2004.1403003

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Citations (2)

Experimental Investigation on the Leakage Reverse Current Component Flowing at the Semiconductor PN Junction Periphery

V.V.N. Obreja C. Codreanu

Due to high level of the leakage reverse current, commercial power silicon diodes available at this time have no specification in the data sheets for operation above 200 degC junction temperature. An experimental method is presented to extract information about the uniformity of the reverse current flow over the silicon die area. The power diode with copper attached heat sink is placed in a hot chamber where the temperature is set, so that the level of reverse current to be enough for heat generation. For the same applied power dissipation at reverse and forward bias, the additional junction temperature increase is monitored by the level of reverse current or by the level of the forward current at constant voltage. Experiments have been performed on commercial silicon diode samples in metallic package. It has been found that the additional junction temperature increase is significantly different, when the same power dissipation is applied at reverse bias and then at forward bias voltage, with the device placed in hot chamber at 200degC or 250 degC, depending on the current level

Reverse leakage current

p–n junction

10.1109/esime.2006.1644014

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Citations (2)

Biosensor Array Based Platform for Pesticide Detection

Sensor Letters (2013)

Carmen Moldovan Rodica Iosub C. Codreanu Bogdan Firtat Daniel Necula

10.1166/sl.2013.2841

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Citations (4)

Edge current induced failure of semiconductor PN junction during operation in the breakdown region of electrical characteristic