C. Podaru

National Institute for Research and Development in Microtechnologies

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E. Manea

National Institute for Research and Development in Microtechnologies

A. Coraci

National Institute for Research and Development in Microtechnologies

V.V.N. Obreja

National Institute for Research and Development in Microtechnologies

M. Purica

National Institute for Research and Development in Microtechnologies

C. Codreanu

National Institute for Research and Development in Microtechnologies

Cristian Ravariu

Universitatea Națională de Știință și Tehnologie Politehnica București

E. Budianu

National Institute for Research and Development in Microtechnologies

I. Cernica

National Institute for Research and Development in Microtechnologies

F. Babarada

Universitatea Națională de Știință și Tehnologie Politehnica București

Alina Popescu

National Research & Development Institute for Textiles and Leather

Cooperative Institutions

National Institute for Research and Development in Microtechnologies

Universitatea Națională de Știință și Tehnologie Politehnica București

University of Bucharest

Transylvania University of Brașov

National Institute of Research and Development for Technical Physics

National Institute For Chemical Pharmaceutical Research and Development

Alexandru Ioan Cuza University

Romanian Academy

National Institute for Laser Plasma and Radiation Physics

Gheorghe Asachi Technical University of Iași

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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)

Failure Analysis of Diode (Thyristor) Dice from Power Semiconductor Modules after Operation above the Maximum Specified Temperature

2006 1st Electronic Systemintegration Technology Conference (2006)

V.V.N. Obreja C. Podaru E. Manea Cosmin Obreja Paul Svasta

Reliability of power modules based on rectifier diode and thyristor devices, above the maximum junction temperature of 125 degC or 150 degC specified in the data sheets has been investigated. Excessive high level of the reverse (blocking current) causing electrical characteristic instability above 150 degC is still a limiting factor for module reliability. Diode and thyristor dice with glass passivation or silicone rubber passivation have been found after module package de-capsulation. Both junction passivation methods indicated excessive high leakage current at the junction edge in power modules. In some modules the level of reverse (blocking) current has been found significantly lower, due to better control of the leakage at the junction edge. Nonetheless continuous current increase may take place with the time above the maximum temperature due to mechanical stress in the package. For rectifier bridge modules with maximum junction temperature of 150 degC, significant increase of the reverse current level has been found after simple storage at 200 degC. Such change was observed especially for silicone rubber passivated junction devices incorporated in the module package. Reliable operation above 150 degC is possible with further advance in the junction passivation techniques and module packaging

Reverse leakage current

Passivation

10.1109/estc.2006.280167

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Citations (2)

Technological Methods for Low Temperature Microfluidic Devices Microfabrication

International Semiconductor Conference (2007)

A. Coraci C. Podaru E. Manea Erou Iancu Alina Ciuciumis

The microchannel based microfluidic devices were obtained using techniques assuming thermal treatments up to 1000°C affecting the processes previously realized on the IC chip. This paper aims to realize low temperature technological processes to obtain microfluidic devices used for biological applications, and in thermal transfer as micro-heat sinks, used in IC chip cooling. The both methods use the positive resist as a sacrificial layer, for the first one having thickness 2 μm obtaining semicircular channels with applications in biology, for second one 15-20 μm, obtaining near-rectangular channels having applications in thermal transfer for IC chip cooling.

Microchannel

Lab-on-a-Chip

10.1109/smicnd.2007.4519658

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Citations (1)

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)

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)

Front Surface Texturing Processes for Silicon Solar Cells

CAS proceedings (2007)

E. Manea E. Budianu M. Purica C. Podaru Alina Popescu

This paper presents the results of an experimental study regarding the increase in the efficiency of the silicon solar cells, using various methods for texturing the front surface. Designing, patterning and surface etching processes led to obtain reined structures with very low losses of the incident optical radiation. This paper aims to compare the fabrication method using the proposed textured surfaces with the standard method.

10.1109/smicnd.2007.4519678

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Citations (3)

MEMS switches: design and manufacturing

D. Vasilache C. Tibeică V. Moagar R. Enachescu M. Iordache

The aim of this paper is to present first MEMS switch structures designed and manufactured in IMT. Switch structures with different length were designed, manufactured and measured. Comparisons between simulated and measured results are also presented.

10.1109/smicnd.2004.1402831

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Citations (1)

EXPERIMENTALDRAINI-VCHARACTERISTICSOFPOWER MOS TRANSISTORSAND THE NATURE OFREVERSELEAKAGE CURRENT OFOXIDEPASSIVATEDPNJUNCTIONS

C. Podaru A. Coraci C. Codreanu

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An amperometric glucose biosensor

C. Podaru C. Bostam C. Malide O. Neagoe Monica Simion

In this paper a miniature, enzyme based, amperometric glucose biosensor is described. A new technology was developed: an Al/sub 2/O/sub 3/ porous anodic film, acting as a cathalytical membrane, assures a better adhesion of the polymeric films which contain the embedded enzyme. The experiments have shown a good linearity (nonlinearity less than 2%) in the range 10-20 mM glucose concentration.

Amperometry

Glucose oxidase

Linearity

10.1109/smicnd.1996.557315

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Citations (7)

Design and fabrication of diffractive optical elements

M. Kusko Dan Cojoc D. Apostol R. Müller E. Manea

In this paper is presented the design, fabrication and characterization of a binary phase-contrast transmission diffractive optical element made by wet etching of the glass substrate. The etch depth was controlled by profilometry measurement. The experimental result is close to the result obtained by simulations.

Characterization

Diffraction efficiency

10.1109/smicnd.2003.1251370

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Citations (6)