Octavian Buiu - Academia.edu (original) (raw)
Papers by Octavian Buiu
2022 International Semiconductor Conference (CAS)
Sensors, 2015
The current paper reports on a sonochemical synthesis method for manufacturing nanostructured (ty... more The current paper reports on a sonochemical synthesis method for manufacturing nanostructured (typical grain size of 50 nm) SrTi0.6Fe0.4O2.8 (Sono-STFO40) powder. This powder is characterized using X ray-diffraction (XRD), Mössbauer spectroscopy and Scanning Electron Microscopy (SEM), and results are compared with commercially available SrTi0.4Fe0.6O2.8 (STFO60) powder. In order to manufacture resistive oxygen sensors, both Sono-STFO40 and STFO60 are deposited, by dip-pen nanolithography (DPN) method, on an SOI (Silicon-on-Insulator) micro-hotplate, employing a tungsten heater embedded within a dielectric membrane. Oxygen detection tests are performed in both dry (RH = 0%) and humid (RH = 60%) nitrogen atmosphere, varying oxygen concentrations between 1% and 16% (v/v), at a constant heater temperature of 650 °C. The oxygen sensor, based on the Sono-STFO40 sensing layer, shows good sensitivity, low power consumption (80 mW), and short response time (25 s). These performance are
Journal of The Electrochemical Society, 2008
ABSTRACT In this work, we present experimental results examining the energy distribution of the r... more ABSTRACT In this work, we present experimental results examining the energy distribution of the relatively high (> 1 X 10(11) cm(-2)) electrically active interface defects which are commonly observed in high-dielectric-constant (high-k) metal-insulator-silicon systems during high-k process development. This paper extends previous studies on the Si(100)/SiOx/HfO2 system to include a comparative analysis of the density and energy distribution of interface defects for HfO2, lanthanum silicate (LaSiOx), and Gd2O3 thin films on (100) orientation silicon formed by a range of deposition techniques. The analysis of the interface defect density across the energy gap, for samples which experience no H-2/N-2 annealing following the gate stack formation, reveals a peak density (similar to 2 X 10(12) cm(-2) eV(-1) to similar to 1 X 10(13) cm(-2) eV(-1)) at 0.83-0.92 eV above the silicon valence bandedge for the HfO2, LaSiOx, and Gd2O3 thin films on Si (100). The characteristic peak in the interface state density (0.83-0.92 eV) is obtained for samples where no interface silicon oxide layer is observed from transmission electron microscopy. Analysis suggests silicon dangling bond (P-bo) centers as the common origin for the dominant interface defects for the various Si(100)/SiOx/high-k/metal gate systems. The results of forming gas (H-2/N-2) annealing over the temperature range 350-555 degrees C are presented and indicate interface state density reduction, as expected for silicon dangling bond centers. The technological relevance of the results is discussed. (c) 2007 The Electrochemical Society.
Microelectronics Reliability, 2003
ABSTRACT Operation of power silicon devices above the maximum permissible specified junction temp... more ABSTRACT Operation of power silicon devices above the maximum permissible specified junction temperature can lead to device catastrophic failure that is usually caused by an electrical short-circuit located at the junction peripheral surface. It is shown that a noticeable surface leakage reverse current found in the available commercial devices may cause I-V reverse characteristic instability through thermal runaway and finally device failure. Suitable junction passivation can reduce further the surface component, so that reliable operation above 200 oC junction temperature to be possible at least for standard recovery PN junction devices.
Proceedings of the 12th International Symposium on the Physical and Failure Analysis of Integrated Circuits, 2005. IPFA 2005.
The aim of the paper is to provide experimental results and analysis relating to the failure mech... more The aim of the paper is to provide experimental results and analysis relating to the failure mechanism of the junction at operation near or in the breakdown region of electrical characteristic.
Solid-State Electronics, 2007
From experimental literature data on metal oxides combined with theoretical estimates, we present... more From experimental literature data on metal oxides combined with theoretical estimates, we present empirical relations for k-values and energy band offset values, that can be used in the search for gate dielectric materials fulfilling the needs of future CMOS generations. Only a few materials investigated so far have properties meeting the demands for k and energy band offset values in the development of CMOS down to 22 nm.
1997 International Semiconductor Conference 20th Edition. CAS '97 Proceedings
The dry etch of polysilicon doped with phosphorus using a parallel plate etcher was studied. A st... more The dry etch of polysilicon doped with phosphorus using a parallel plate etcher was studied. A standard dry etching process program (used in CMOS 3 μm technology) was compared with a proposed modified program in order to obtain a better anisotropy and lower values for underetching and dimensional dispersion on the wafer
Thin Solid Films, 1999
Plasma oxidation represents a good alternative method of obtaining low temperature. good electric... more Plasma oxidation represents a good alternative method of obtaining low temperature. good electrical quality thin dielectric films. By using light irradiation during growth an enhancement in the growth rates may be obtained. even at low temperatures t95-140°C). The experimental results are compared with typical values. obtained from a system without any irradiation during processing. For both cases a linear-parabolic growth law is valid: however in order to esplain the experimental results. we show that the charge carriers generated by the light heating system generate an important increase in the electric field at the interface. leading to a significant increase of oxidation reaction rate. The resultj are important both for the theoretical understanding of plasma oxidation and for the design of very low temperature t< 100°C) plasma anodisation equipment.
Microelectronic Engineering, 2009
The optical dielectric functions for hafnium oxide and hafnium silicate films were extracted from... more The optical dielectric functions for hafnium oxide and hafnium silicate films were extracted from spectroscopic ellipsometry measurements and the density then calculated using a previously proposed method. The values obtained were then compared to those obtained using X-ray reflectometry. The optical dielectric functions for gadolinium oxide films deposited under various conditions were also extracted from spectroscopic ellipsometry measurements. It was found using medium energy ion scattering that gadolinium oxide films deposited using Gd[N(SiCH 3) 2 ] 3 and H 2 O as precursors, contained significant levels of silicon and the silicon concentration was directly proportional to the wafer deposition temperature. This effect was also observed in the density measurements extracted from spectroscopic ellipsometry data.
Materials Science in Semiconductor Processing, 2006
It is shown that the high base current and associated low-frequency noise typical for the SiGe HB... more It is shown that the high base current and associated low-frequency noise typical for the SiGe HBTs prepared by the selective epitaxial growth of the collector and non-selective epitaxial growth of the base and emitter (SEG/NSEG technology), can be related to the mechanical stress between the collector and the field oxide surrounding the collector in these devices. The reason is that such stress provokes the viscous flow of the surface oxide producing an ''action-atdistance'' effect which results in the creation of additional fast and slow surface centers at the single crystal emitter and passivating oxide interface and in the oxide, respectively. The increase of fast center density increases the recombination base current component while the increase of slow center density increases the intensity of the 1/f noise source. As a result, any factor that promotes the reduction of the stress or the decrease of the intensity of the surface oxide viscous flow serves to decrease the base current and its 1/f noise. Thus we have found that we can mitigate the undesirable effects by the following solutions: increasing the temperature of the SEG of the collector T SEG , decreasing the temperature of the rapid thermal activation T RTA , implantation of BF 2 into the field oxide before the collector and base layers are grown, replacement of the bulk substrate by SOI. It is shown that the maximal decreases of the base current I B and of the spectral density of the 1/f noise S IB are as high as factors of 30 and 8000, respectively. Therefore, the technology conditions have been identified to guarantee a sufficiently low level of both excess base current noise and base current.
IEEE Electron Device Letters, 2006
A simple process for the fabrication of shallow drain junctions on pillar sidewalls in sub-100-nm... more A simple process for the fabrication of shallow drain junctions on pillar sidewalls in sub-100-nm vertical MOSFETs is described. The key feature of this process is the creation of a polysilicon spacer around the perimeter of the pillar to connect the channel to a polysilicon drain contact. The depth of the junction on the pillar sidewall is primarily determined by the thickness of the polysilicon spacer. This process is CMOS compatible and, hence, facilitates the integration of a sub-100-nm vertical MOSFET in a planar CMOS technology using mature lithography. The fabricated transistors have a subthreshold slope of 95 mV/dec (at V DS = 1 V) and a drain-induced barrier lowering of 0.12 V.
IEEE Transactions on Electron Devices, 2005
A technology is described for fabricating SiGe heterojunction bipolar transistors (HBTs) on wafer... more A technology is described for fabricating SiGe heterojunction bipolar transistors (HBTs) on wafer-bonded silicon-oninsulator (SOI) substrates that incorporate buried tungsten silicide layers for collector resistance reduction or buried groundplanes for crosstalk suppression. The physical structure of the devices is characterized using cross section transmission electron microscopy, and the electrical properties of the buried tungsten silicide layer are characterized using sheet resistance measurements as a function of bond temperature. Possible contamination issues associated with the buried tungsten silicide layer are investigated by measuring the collector/base reverse diode tics. A resistivity of 50 cm is obtained for the buried silicide layer for a bond anneal of 120 min at 1000 C. Collector/base reverse diode tics show a voltage dependence of approximately 1 2 , indicating that the leakage current is due to Shockley-Read-Hall generation in the depletion region. Fitting of the current-voltage tics gives a generation lifetime of 90 ns, which is as expected for the collector doping of 7 10 17 cm 3. These results indicate that the buried tungsten silicide layer does not have a serious impact on junction leakage.
The paper looks into the use of Nanostructured metal oxides as sensing layer for ethanol. Using t... more The paper looks into the use of Nanostructured metal oxides as sensing layer for ethanol. Using the HSAB rules for analyzing the chemiresistive ethanol sensor based on semiconducting metal oxides, three different cases have been identified and are discussed in the paper.
CAS 2010 Proceedings (International Semiconductor Conference), 2010
The Hard Soft Acid Base (HSAB) theory is introduced as a new tool to select or design sensitive m... more The Hard Soft Acid Base (HSAB) theory is introduced as a new tool to select or design sensitive materials for carbon dioxide detection with SAW-BAW (Surface Acoustic Waves - Bulk Acoustic Waves) devices. According to HSAB, CO2 is hard acid, thus small organic or inorganic molecules, or polymers which can act as hard bases could be suitable candidates as sensing
2008 International Semiconductor Conference, 2008
The synthesis of two new types of nanocomposite matrices, the first based on polyallylamine (PAA)... more The synthesis of two new types of nanocomposite matrices, the first based on polyallylamine (PAA) and aminocarbon nanotubes, the second on polyethyleneimine (PEI) and aminocarbon nanotubes, are reported. The surface acoustic wave (SAW) sensors, coated with the two selected nanocomposites, showed good sensitivities when varying the CO2 concentrations in the range (500-5000) ppm. The sensor sensitivity is larger when using
CAS 2012 (International Semiconductor Conference), 2012
ABSTRACT This paper introduces a pressure sensing structure configured as a stress sensitive diff... more ABSTRACT This paper introduces a pressure sensing structure configured as a stress sensitive differential amplifier (SSDA), built on a Silicon-on-Insulator (SOI) membrane. Theoretical calculation show the significant increase in sensitivity which is expected from the pressure sensors in SSDA configuration compared to the traditional Wheatstone bridge circuit. Preliminary experimental measurements, performed on individual transistors placed on the membrane, exhibit state-the-art sensitivity values (1.45mV/mbar).
Ceramics International, 2014
Multilayered titania (TiO 2) films have been prepared via sol-gel dip-coating method from a tetra... more Multilayered titania (TiO 2) films have been prepared via sol-gel dip-coating method from a tetraethyl-orthotitanate solution that contains 2 g of polyethylene glycol (PEG) with different molecular weight (6000, 20,000 and 35,000). The films were deposited on fluorine doped tin oxide (FTO) coated glass and annealed by a thermal treatment at 450 1C for 30 min. We demonstrated how the structure, the morphology and the optical properties of the films can be controlled by varying the PEG molecular weight and number of depositions. The correlation between these parameters and the film properties was investigated. Sol-gel deposited and PEG doped TiO 2 films demonstrate better properties for their use in solar cell applications, by enhancing the transmittance value in the 380-540 nm range.
2016 International Semiconductor Conference (CAS), 2016
Li-ion batteries are the most popular energy storage choice for a wide range of applications, esp... more Li-ion batteries are the most popular energy storage choice for a wide range of applications, especially electric and hybrid electric vehicles, because of their superior characteristics in comparison to the other energy storage technologies. It has been observed that there are significant differences regarding parameters within the same batch of batteries manufactured and that mainly due to technological barriers which cannot be over passed without expensive efforts. To avoid additional stress and battery premature destruction it is necessary to develop a new approach for balancing between cells during electrical or hybrid-electrical vehicles driving cycles. This paper presents a thorough behavioral study of Li-ion cells during the ageing phenomenon, as well as the possibility of employing electrochemical impedance spectroscopy for assessing the batteries state-of-health. The latter can be used to further develop a coherent algorithm to be employed in a smart adaptive balancing system.
2022 International Semiconductor Conference (CAS)
Sensors, 2015
The current paper reports on a sonochemical synthesis method for manufacturing nanostructured (ty... more The current paper reports on a sonochemical synthesis method for manufacturing nanostructured (typical grain size of 50 nm) SrTi0.6Fe0.4O2.8 (Sono-STFO40) powder. This powder is characterized using X ray-diffraction (XRD), Mössbauer spectroscopy and Scanning Electron Microscopy (SEM), and results are compared with commercially available SrTi0.4Fe0.6O2.8 (STFO60) powder. In order to manufacture resistive oxygen sensors, both Sono-STFO40 and STFO60 are deposited, by dip-pen nanolithography (DPN) method, on an SOI (Silicon-on-Insulator) micro-hotplate, employing a tungsten heater embedded within a dielectric membrane. Oxygen detection tests are performed in both dry (RH = 0%) and humid (RH = 60%) nitrogen atmosphere, varying oxygen concentrations between 1% and 16% (v/v), at a constant heater temperature of 650 °C. The oxygen sensor, based on the Sono-STFO40 sensing layer, shows good sensitivity, low power consumption (80 mW), and short response time (25 s). These performance are
Journal of The Electrochemical Society, 2008
ABSTRACT In this work, we present experimental results examining the energy distribution of the r... more ABSTRACT In this work, we present experimental results examining the energy distribution of the relatively high (> 1 X 10(11) cm(-2)) electrically active interface defects which are commonly observed in high-dielectric-constant (high-k) metal-insulator-silicon systems during high-k process development. This paper extends previous studies on the Si(100)/SiOx/HfO2 system to include a comparative analysis of the density and energy distribution of interface defects for HfO2, lanthanum silicate (LaSiOx), and Gd2O3 thin films on (100) orientation silicon formed by a range of deposition techniques. The analysis of the interface defect density across the energy gap, for samples which experience no H-2/N-2 annealing following the gate stack formation, reveals a peak density (similar to 2 X 10(12) cm(-2) eV(-1) to similar to 1 X 10(13) cm(-2) eV(-1)) at 0.83-0.92 eV above the silicon valence bandedge for the HfO2, LaSiOx, and Gd2O3 thin films on Si (100). The characteristic peak in the interface state density (0.83-0.92 eV) is obtained for samples where no interface silicon oxide layer is observed from transmission electron microscopy. Analysis suggests silicon dangling bond (P-bo) centers as the common origin for the dominant interface defects for the various Si(100)/SiOx/high-k/metal gate systems. The results of forming gas (H-2/N-2) annealing over the temperature range 350-555 degrees C are presented and indicate interface state density reduction, as expected for silicon dangling bond centers. The technological relevance of the results is discussed. (c) 2007 The Electrochemical Society.
Microelectronics Reliability, 2003
ABSTRACT Operation of power silicon devices above the maximum permissible specified junction temp... more ABSTRACT Operation of power silicon devices above the maximum permissible specified junction temperature can lead to device catastrophic failure that is usually caused by an electrical short-circuit located at the junction peripheral surface. It is shown that a noticeable surface leakage reverse current found in the available commercial devices may cause I-V reverse characteristic instability through thermal runaway and finally device failure. Suitable junction passivation can reduce further the surface component, so that reliable operation above 200 oC junction temperature to be possible at least for standard recovery PN junction devices.
Proceedings of the 12th International Symposium on the Physical and Failure Analysis of Integrated Circuits, 2005. IPFA 2005.
The aim of the paper is to provide experimental results and analysis relating to the failure mech... more The aim of the paper is to provide experimental results and analysis relating to the failure mechanism of the junction at operation near or in the breakdown region of electrical characteristic.
Solid-State Electronics, 2007
From experimental literature data on metal oxides combined with theoretical estimates, we present... more From experimental literature data on metal oxides combined with theoretical estimates, we present empirical relations for k-values and energy band offset values, that can be used in the search for gate dielectric materials fulfilling the needs of future CMOS generations. Only a few materials investigated so far have properties meeting the demands for k and energy band offset values in the development of CMOS down to 22 nm.
1997 International Semiconductor Conference 20th Edition. CAS '97 Proceedings
The dry etch of polysilicon doped with phosphorus using a parallel plate etcher was studied. A st... more The dry etch of polysilicon doped with phosphorus using a parallel plate etcher was studied. A standard dry etching process program (used in CMOS 3 μm technology) was compared with a proposed modified program in order to obtain a better anisotropy and lower values for underetching and dimensional dispersion on the wafer
Thin Solid Films, 1999
Plasma oxidation represents a good alternative method of obtaining low temperature. good electric... more Plasma oxidation represents a good alternative method of obtaining low temperature. good electrical quality thin dielectric films. By using light irradiation during growth an enhancement in the growth rates may be obtained. even at low temperatures t95-140°C). The experimental results are compared with typical values. obtained from a system without any irradiation during processing. For both cases a linear-parabolic growth law is valid: however in order to esplain the experimental results. we show that the charge carriers generated by the light heating system generate an important increase in the electric field at the interface. leading to a significant increase of oxidation reaction rate. The resultj are important both for the theoretical understanding of plasma oxidation and for the design of very low temperature t< 100°C) plasma anodisation equipment.
Microelectronic Engineering, 2009
The optical dielectric functions for hafnium oxide and hafnium silicate films were extracted from... more The optical dielectric functions for hafnium oxide and hafnium silicate films were extracted from spectroscopic ellipsometry measurements and the density then calculated using a previously proposed method. The values obtained were then compared to those obtained using X-ray reflectometry. The optical dielectric functions for gadolinium oxide films deposited under various conditions were also extracted from spectroscopic ellipsometry measurements. It was found using medium energy ion scattering that gadolinium oxide films deposited using Gd[N(SiCH 3) 2 ] 3 and H 2 O as precursors, contained significant levels of silicon and the silicon concentration was directly proportional to the wafer deposition temperature. This effect was also observed in the density measurements extracted from spectroscopic ellipsometry data.
Materials Science in Semiconductor Processing, 2006
It is shown that the high base current and associated low-frequency noise typical for the SiGe HB... more It is shown that the high base current and associated low-frequency noise typical for the SiGe HBTs prepared by the selective epitaxial growth of the collector and non-selective epitaxial growth of the base and emitter (SEG/NSEG technology), can be related to the mechanical stress between the collector and the field oxide surrounding the collector in these devices. The reason is that such stress provokes the viscous flow of the surface oxide producing an ''action-atdistance'' effect which results in the creation of additional fast and slow surface centers at the single crystal emitter and passivating oxide interface and in the oxide, respectively. The increase of fast center density increases the recombination base current component while the increase of slow center density increases the intensity of the 1/f noise source. As a result, any factor that promotes the reduction of the stress or the decrease of the intensity of the surface oxide viscous flow serves to decrease the base current and its 1/f noise. Thus we have found that we can mitigate the undesirable effects by the following solutions: increasing the temperature of the SEG of the collector T SEG , decreasing the temperature of the rapid thermal activation T RTA , implantation of BF 2 into the field oxide before the collector and base layers are grown, replacement of the bulk substrate by SOI. It is shown that the maximal decreases of the base current I B and of the spectral density of the 1/f noise S IB are as high as factors of 30 and 8000, respectively. Therefore, the technology conditions have been identified to guarantee a sufficiently low level of both excess base current noise and base current.
IEEE Electron Device Letters, 2006
A simple process for the fabrication of shallow drain junctions on pillar sidewalls in sub-100-nm... more A simple process for the fabrication of shallow drain junctions on pillar sidewalls in sub-100-nm vertical MOSFETs is described. The key feature of this process is the creation of a polysilicon spacer around the perimeter of the pillar to connect the channel to a polysilicon drain contact. The depth of the junction on the pillar sidewall is primarily determined by the thickness of the polysilicon spacer. This process is CMOS compatible and, hence, facilitates the integration of a sub-100-nm vertical MOSFET in a planar CMOS technology using mature lithography. The fabricated transistors have a subthreshold slope of 95 mV/dec (at V DS = 1 V) and a drain-induced barrier lowering of 0.12 V.
IEEE Transactions on Electron Devices, 2005
A technology is described for fabricating SiGe heterojunction bipolar transistors (HBTs) on wafer... more A technology is described for fabricating SiGe heterojunction bipolar transistors (HBTs) on wafer-bonded silicon-oninsulator (SOI) substrates that incorporate buried tungsten silicide layers for collector resistance reduction or buried groundplanes for crosstalk suppression. The physical structure of the devices is characterized using cross section transmission electron microscopy, and the electrical properties of the buried tungsten silicide layer are characterized using sheet resistance measurements as a function of bond temperature. Possible contamination issues associated with the buried tungsten silicide layer are investigated by measuring the collector/base reverse diode tics. A resistivity of 50 cm is obtained for the buried silicide layer for a bond anneal of 120 min at 1000 C. Collector/base reverse diode tics show a voltage dependence of approximately 1 2 , indicating that the leakage current is due to Shockley-Read-Hall generation in the depletion region. Fitting of the current-voltage tics gives a generation lifetime of 90 ns, which is as expected for the collector doping of 7 10 17 cm 3. These results indicate that the buried tungsten silicide layer does not have a serious impact on junction leakage.
The paper looks into the use of Nanostructured metal oxides as sensing layer for ethanol. Using t... more The paper looks into the use of Nanostructured metal oxides as sensing layer for ethanol. Using the HSAB rules for analyzing the chemiresistive ethanol sensor based on semiconducting metal oxides, three different cases have been identified and are discussed in the paper.
CAS 2010 Proceedings (International Semiconductor Conference), 2010
The Hard Soft Acid Base (HSAB) theory is introduced as a new tool to select or design sensitive m... more The Hard Soft Acid Base (HSAB) theory is introduced as a new tool to select or design sensitive materials for carbon dioxide detection with SAW-BAW (Surface Acoustic Waves - Bulk Acoustic Waves) devices. According to HSAB, CO2 is hard acid, thus small organic or inorganic molecules, or polymers which can act as hard bases could be suitable candidates as sensing
2008 International Semiconductor Conference, 2008
The synthesis of two new types of nanocomposite matrices, the first based on polyallylamine (PAA)... more The synthesis of two new types of nanocomposite matrices, the first based on polyallylamine (PAA) and aminocarbon nanotubes, the second on polyethyleneimine (PEI) and aminocarbon nanotubes, are reported. The surface acoustic wave (SAW) sensors, coated with the two selected nanocomposites, showed good sensitivities when varying the CO2 concentrations in the range (500-5000) ppm. The sensor sensitivity is larger when using
CAS 2012 (International Semiconductor Conference), 2012
ABSTRACT This paper introduces a pressure sensing structure configured as a stress sensitive diff... more ABSTRACT This paper introduces a pressure sensing structure configured as a stress sensitive differential amplifier (SSDA), built on a Silicon-on-Insulator (SOI) membrane. Theoretical calculation show the significant increase in sensitivity which is expected from the pressure sensors in SSDA configuration compared to the traditional Wheatstone bridge circuit. Preliminary experimental measurements, performed on individual transistors placed on the membrane, exhibit state-the-art sensitivity values (1.45mV/mbar).
Ceramics International, 2014
Multilayered titania (TiO 2) films have been prepared via sol-gel dip-coating method from a tetra... more Multilayered titania (TiO 2) films have been prepared via sol-gel dip-coating method from a tetraethyl-orthotitanate solution that contains 2 g of polyethylene glycol (PEG) with different molecular weight (6000, 20,000 and 35,000). The films were deposited on fluorine doped tin oxide (FTO) coated glass and annealed by a thermal treatment at 450 1C for 30 min. We demonstrated how the structure, the morphology and the optical properties of the films can be controlled by varying the PEG molecular weight and number of depositions. The correlation between these parameters and the film properties was investigated. Sol-gel deposited and PEG doped TiO 2 films demonstrate better properties for their use in solar cell applications, by enhancing the transmittance value in the 380-540 nm range.
2016 International Semiconductor Conference (CAS), 2016
Li-ion batteries are the most popular energy storage choice for a wide range of applications, esp... more Li-ion batteries are the most popular energy storage choice for a wide range of applications, especially electric and hybrid electric vehicles, because of their superior characteristics in comparison to the other energy storage technologies. It has been observed that there are significant differences regarding parameters within the same batch of batteries manufactured and that mainly due to technological barriers which cannot be over passed without expensive efforts. To avoid additional stress and battery premature destruction it is necessary to develop a new approach for balancing between cells during electrical or hybrid-electrical vehicles driving cycles. This paper presents a thorough behavioral study of Li-ion cells during the ageing phenomenon, as well as the possibility of employing electrochemical impedance spectroscopy for assessing the batteries state-of-health. The latter can be used to further develop a coherent algorithm to be employed in a smart adaptive balancing system.