M. Halbwax - Academia.edu (original) (raw)

Papers by M. Halbwax

Research paper thumbnail of Electrical and Chemical Studies on Al2O3 Passivation Activation Process

Energy Procedia, 2014

Al2O3 deposited using Atomic layer Deposition (ALD) technique is known as an excellent material f... more Al2O3 deposited using Atomic layer Deposition (ALD) technique is known as an excellent material for p-type silicon surface passivation. However a post-deposition annealing step is needed to make the passivation effective. Thanks to coupled electrical measurements (capacitance and photoconductance) and chemical analyses (X-ray Photoelectron Spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS)) carried out on the same p-type Cz silicon sample, a closer explanation of this activation process is given. The presence of hydrogen and oxygen is correlated to the evolution of the electrical parameters and the minority carrier lifetime for 0 to 60 min 450°C annealing.

Research paper thumbnail of <title>Femtosecond laser for black silicon and photovoltaic cells</title>

Commercial and Biomedical Applications of Ultrafast Lasers VIII, 2008

We have prepared absorbing structures for photovoltaic cells with different nano-texturization, o... more We have prepared absorbing structures for photovoltaic cells with different nano-texturization, obtained by means of a femtosecond laser, without the use of corrosive gas (i.e. under vacuum). To take in account the 3D structured front surface, the emitter doping has been realized by using Plasma Immersion Ion Implantation (so-called PULSION). The results show a photocurrent increase up to 60 % in the laser texturized zones.

Research paper thumbnail of Kinetics of the heteroepitaxial growth of Ge layer at low temperature on Si(001) in UHV-CVD

The Ge growth at 330 °C by ultrahigh vacuum chemical vapour deposition is investigated in real ti... more The Ge growth at 330 °C by ultrahigh vacuum chemical vapour deposition is investigated in real time by reflection high energy electron diffraction (RHEED) in combination with atomic force microscopy and Rutherford back scattering spectrometry (RBS). The Stranski-Krastanov-related 2D to 3D transition is avoided at low temperature and the major part of the relaxation process occurs during the deposition of

Research paper thumbnail of Ultra-short pulsed laser for nano-texturization associated to plasma immersion implantation for 3D shallow doping: Application to silicon photovoltaic structures

Research paper thumbnail of Femtosecond laser texturization for improvement of photovoltaic cells: Black Silicon

Research paper thumbnail of Formation and properties of selectively grown Ge/Si quantum dots

Superlattices and Microstructures, 2004

The selective epitaxial growth of Si layers and Ge quantum dots in windows patterned in oxidized ... more The selective epitaxial growth of Si layers and Ge quantum dots in windows patterned in oxidized Si(001) was investigated. The selectively deposited Si layers were found to develop towards truncated pyramids limited by {113} facets until the (001) top face disappears. By this way, the Ge dot formation on the (001) surface can then be controlled by adjusting the height of the truncated Si(001) pyramids grown prior to Ge deposition. By monitoring the facet formation during the growth of the Si layers, we showed that it is possible to form single or several Ge dots per window. We have then investigated the formation of Ge dots in stacked selectively grown layers. The Ge dots exhibit a vertical ordering along the growth direction. The optical and electrical properties of Ge dots grown both by selective growth and by self-assembly were investigated. The photoluminescence measurements showed a blue shift of the PL signal from selective Ge dots and the absence of PL from wetting layers as a result of dot size reduction and restricted surface. The forward current-voltage characteristics of Schottky contacts with Ge dots just below the interface exhibit some idealities which can be related to the presence of these dots and indicate that the inhomogeneities are stronger for samples with multilayers of Ge dots.

Research paper thumbnail of UHV-CVD growth and annealing of thin fully relaxed Ge films on (001)Si

Research paper thumbnail of Kinetics of selective epitaxial growth of Si and relaxed Ge by ultrahigh vacuum chemical vapor deposition in Si(001) windows

Materials Science in Semiconductor Processing, 2006

Relaxed germanium was deposited following a low temperature-high temperature procedure by ultrahi... more Relaxed germanium was deposited following a low temperature-high temperature procedure by ultrahigh vacuum chemical vapor deposition in Si trenches opened through a SiO 2 mask. The resulting growth is selective, the germanium fills the Si trenches and evolves towards a roof-shaped morphology limited by (0 0 1), {1 1 3} and {1 1 1} facets. The evolution in height of the Ge structure depends on the trench width, and can be understood by considering a growth rate in the /1 1 3S direction equal to 22% of that measured along the /0 0 1S axis. At last, a surprisingly strong Ge diffusion under the SiO 2 mask was revealed by selective chemical etching. Such a phenomenon was unexpected because no diffusion through the Si/Ge interface was previously observed on plain wafer. r

Research paper thumbnail of Selective epitaxial growth of Ge quantum dots on patterned SiO2/Si(0 0 1) surfaces

Applied Surface Science, 2004

... It was shown that the growth of the Si buffer layers evolved towards truncated pyramids whose... more ... It was shown that the growth of the Si buffer layers evolved towards truncated pyramids whose top area can be controlled via the Si growth time. ... As can be seen from the figure, for window dimension of about 150 nm, only one Ge dot was formed near the center of a window (Fig. ...

Research paper thumbnail of Localized laser thermal annealing of nanometric SiGe layers protected by a dielectric Bragg mirror

Thin Solid Films, 2008

ABSTRACT The use of Ge nanostructures in microelectronic devices requires quite low thermal budge... more ABSTRACT The use of Ge nanostructures in microelectronic devices requires quite low thermal budget processes. In this paper, we report on the development of a technique which enables the localization of laser thermal annealing. Dielectric layers have been deposited on a sample which contains stacks of Ge islands in order to obtain a maximum reflectivity at the wavelength of an XeCl laser (308 nm). We demonstrate that the damage threshold of the dielectric mirror highly depends on the presence of hydrogen in the stack. Last but not least, we demonstrate that localized melting of the surface can be achieved.

Research paper thumbnail of Electrical and Chemical Studies on Al2O3 Passivation Activation Process

Energy Procedia, 2014

Al2O3 deposited using Atomic layer Deposition (ALD) technique is known as an excellent material f... more Al2O3 deposited using Atomic layer Deposition (ALD) technique is known as an excellent material for p-type silicon surface passivation. However a post-deposition annealing step is needed to make the passivation effective. Thanks to coupled electrical measurements (capacitance and photoconductance) and chemical analyses (X-ray Photoelectron Spectroscopy (XPS) and Secondary Ion Mass Spectrometry (SIMS)) carried out on the same p-type Cz silicon sample, a closer explanation of this activation process is given. The presence of hydrogen and oxygen is correlated to the evolution of the electrical parameters and the minority carrier lifetime for 0 to 60 min 450°C annealing.

Research paper thumbnail of <title>Femtosecond laser for black silicon and photovoltaic cells</title>

Commercial and Biomedical Applications of Ultrafast Lasers VIII, 2008

We have prepared absorbing structures for photovoltaic cells with different nano-texturization, o... more We have prepared absorbing structures for photovoltaic cells with different nano-texturization, obtained by means of a femtosecond laser, without the use of corrosive gas (i.e. under vacuum). To take in account the 3D structured front surface, the emitter doping has been realized by using Plasma Immersion Ion Implantation (so-called PULSION). The results show a photocurrent increase up to 60 % in the laser texturized zones.

Research paper thumbnail of Kinetics of the heteroepitaxial growth of Ge layer at low temperature on Si(001) in UHV-CVD

The Ge growth at 330 °C by ultrahigh vacuum chemical vapour deposition is investigated in real ti... more The Ge growth at 330 °C by ultrahigh vacuum chemical vapour deposition is investigated in real time by reflection high energy electron diffraction (RHEED) in combination with atomic force microscopy and Rutherford back scattering spectrometry (RBS). The Stranski-Krastanov-related 2D to 3D transition is avoided at low temperature and the major part of the relaxation process occurs during the deposition of

Research paper thumbnail of Ultra-short pulsed laser for nano-texturization associated to plasma immersion implantation for 3D shallow doping: Application to silicon photovoltaic structures

Research paper thumbnail of Femtosecond laser texturization for improvement of photovoltaic cells: Black Silicon

Research paper thumbnail of Formation and properties of selectively grown Ge/Si quantum dots

Superlattices and Microstructures, 2004

The selective epitaxial growth of Si layers and Ge quantum dots in windows patterned in oxidized ... more The selective epitaxial growth of Si layers and Ge quantum dots in windows patterned in oxidized Si(001) was investigated. The selectively deposited Si layers were found to develop towards truncated pyramids limited by {113} facets until the (001) top face disappears. By this way, the Ge dot formation on the (001) surface can then be controlled by adjusting the height of the truncated Si(001) pyramids grown prior to Ge deposition. By monitoring the facet formation during the growth of the Si layers, we showed that it is possible to form single or several Ge dots per window. We have then investigated the formation of Ge dots in stacked selectively grown layers. The Ge dots exhibit a vertical ordering along the growth direction. The optical and electrical properties of Ge dots grown both by selective growth and by self-assembly were investigated. The photoluminescence measurements showed a blue shift of the PL signal from selective Ge dots and the absence of PL from wetting layers as a result of dot size reduction and restricted surface. The forward current-voltage characteristics of Schottky contacts with Ge dots just below the interface exhibit some idealities which can be related to the presence of these dots and indicate that the inhomogeneities are stronger for samples with multilayers of Ge dots.

Research paper thumbnail of UHV-CVD growth and annealing of thin fully relaxed Ge films on (001)Si

Research paper thumbnail of Kinetics of selective epitaxial growth of Si and relaxed Ge by ultrahigh vacuum chemical vapor deposition in Si(001) windows

Materials Science in Semiconductor Processing, 2006

Relaxed germanium was deposited following a low temperature-high temperature procedure by ultrahi... more Relaxed germanium was deposited following a low temperature-high temperature procedure by ultrahigh vacuum chemical vapor deposition in Si trenches opened through a SiO 2 mask. The resulting growth is selective, the germanium fills the Si trenches and evolves towards a roof-shaped morphology limited by (0 0 1), {1 1 3} and {1 1 1} facets. The evolution in height of the Ge structure depends on the trench width, and can be understood by considering a growth rate in the /1 1 3S direction equal to 22% of that measured along the /0 0 1S axis. At last, a surprisingly strong Ge diffusion under the SiO 2 mask was revealed by selective chemical etching. Such a phenomenon was unexpected because no diffusion through the Si/Ge interface was previously observed on plain wafer. r

Research paper thumbnail of Selective epitaxial growth of Ge quantum dots on patterned SiO2/Si(0 0 1) surfaces

Applied Surface Science, 2004

... It was shown that the growth of the Si buffer layers evolved towards truncated pyramids whose... more ... It was shown that the growth of the Si buffer layers evolved towards truncated pyramids whose top area can be controlled via the Si growth time. ... As can be seen from the figure, for window dimension of about 150 nm, only one Ge dot was formed near the center of a window (Fig. ...

Research paper thumbnail of Localized laser thermal annealing of nanometric SiGe layers protected by a dielectric Bragg mirror

Thin Solid Films, 2008

ABSTRACT The use of Ge nanostructures in microelectronic devices requires quite low thermal budge... more ABSTRACT The use of Ge nanostructures in microelectronic devices requires quite low thermal budget processes. In this paper, we report on the development of a technique which enables the localization of laser thermal annealing. Dielectric layers have been deposited on a sample which contains stacks of Ge islands in order to obtain a maximum reflectivity at the wavelength of an XeCl laser (308 nm). We demonstrate that the damage threshold of the dielectric mirror highly depends on the presence of hydrogen in the stack. Last but not least, we demonstrate that localized melting of the surface can be achieved.