Papers by Author: Sandrine Juillaguet

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Authors: Jean-Louis Robert, Sylvie Contreras, Jean Camassel, Julien Pernot, Sandrine Juillaguet, Lea Di Cioccio, Thierry Billon
Authors: Teddy Robert, Maya Marinova, Sandrine Juillaguet, Anne Henry, Efstathios K. Polychroniadis, Jean Camassel
Abstract: A new type of 6H zigzag faults has been identified from high resolution transmission electron microscopy (HRTEM) measurements performed on low-doped 4H-SiC homoepitaxial layer grown on off-axis substrates in a hot-wall CVD reactor. They are made of half unit cells of 6H with corresponding low temperature photoluminescence (LTPL) response ranging from about 3 eV to 2.5 eV at liquid helium temperature.
Authors: Teddy Robert, Sandrine Juillaguet, Maya Marinova, Thierry Chassagne, Ioannis Tsiaousis, N. Frangis, Efstathios K. Polychroniadis, Jean Camassel
Abstract: The electronic structure of in-grown 8H stacking faults in 4H-SiC matrix has been investigated in detail. After assessment of the structural properties by high resolution transmission electron microscopy, we focus on the electronic structure. We show that one unit cell of 8H does not behave like a single type-II quantum well but, rather, like two type-II quantum wells of 3C coupled by a thin hexagonal barrier. Using a transfer matrix method, we compute the corresponding transition energies, taking into account the effect of the valence band offset and built-in electric field. A good agreement is found with the experimental data collected from low temperature photoluminescence spectroscopy.
Authors: Marcin Zielinski, Marc Portail, Thierry Chassagne, Sandrine Juillaguet, Hervé Peyre, André Leycuras, Jean Camassel
Abstract: We report on recent advances in liquid phase epitaxial (LPE) conversion of a bulk Si wafer into self standing 3C-SiC. This includes the role of the stress control within the (100) oriented “crucibles”, the elaboration of crack-free (111) “crucibles” and the successful conversion of (100) and (111) oriented Si wafer. To date up to 100µm thick 3C-SiC(100) as well as 30µm thick crack-free 3C-SiC (111) materials have been obtained. The growth rate ranges from 20 to 100µm/h and locally can even reach ~1mm/h. In this work we focus on the structural, morphological and optical properties of the LPE-grown material.
Authors: Laurence Latu-Romain, Didier Chaussende, Carole Balloud, Sandrine Juillaguet, L. Rapenne, Etienne Pernot, Jean Camassel, Michel Pons, Roland Madar
Abstract: Because of the formation of DPB (Double Positioning Boundary) when starting from a hexagonal <0001> seed, DPB-free 3C-SiC single crystals have never been reported up to now. In a recent work we showed that, using adapted nucleation conditions, one could grow thick 3C-SiC single crystal almost free of DPB [1]. In this work we present the results of a multi-scale investigation of such crystals. Using birefringence microscopy, EBSD and HR-TEM, we find evidence of a continuous improvement of the crystal quality with increasing thickness in the most defected area, at the sample periphery. On the contrary, in the large DPB-free area, the SF density remains rather constant from the interface to the surface. The LTPL spectra collected at 5K on the upper part of samples present a nice resolution of multiple bound exciton features (up to m=5) which clearly shows the high (electronic) quality of our 3C-SiC material.
Authors: Tomasz Sledziewski, Svetlana Beljakowa, Kassem Alassaad, Pawel Kwasnicki, Roxana Arvinte, Sandrine Juillaguet, Marcin Zielinski, Véronique Soulière, Gabriel Ferro, Heiko B. Weber, Michael Krieger
Abstract: We have investigated the electrical properties of n-type 4H-SiC in-situ germanium-doped homoepitaxial layers grown by chemical vapor deposition. Germanium is an isoelectronic impurity and, therefore, not expected to contribute to the conductivity. However, Hall effect measurements taken on samples with and without germanium revealed an enhanced mobility by a factor of ≈2 at T ≈ 55 K in the germanium-doped sample despite equal free electron concentration and equal compensation. Deep level transient spectroscopy (DLTS) measurements taken on germanium-doped samples reveal negative peaks indicating the presence of charged extended defects.
Authors: Didier Chaussende, Carole Balloud, Laurent Auvray, Francis Baillet, Marcin Zielinski, Sandrine Juillaguet, Michel Mermoux, Etienne Pernot, Jean Camassel, Michel Pons, Roland Madar
Authors: Efstathios K. Polychroniadis, Carole Balloud, Sandrine Juillaguet, Gabriel Ferro, Yves Monteil, Jean Camassel, J. Stoemenos
Abstract: The evolution of defects versus thickness has been investigated in three different freestanding 3C-SiC samples, using TEM (Transmission Electron Microscopy) and LTPL (Low Temperature Photo-Luminescence) spectroscopy. In all samples, the stacking fault density reduces rapidly within the first 20 µm of the growth. Then it remains constant, at about 5x103 cm-1 up to the end. This behavior is attributed to the easy generation of stacking faults, even under a very low thermal stress, as in-situ experiments reveal. On the opposite the elimination of inversion domains, by bending boundaries during the growth, is found to be sample dependant. This is in good agreement with LTPL results.
Authors: C. Sartel, Carole Balloud, Véronique Soulière, Sandrine Juillaguet, Jacques Dazord, Yves Monteil, Jean Camassel, S. Rushworth
Authors: Pawel Kwasnicki, Roxana Arvinte, Hervé Peyre, Marcin Zielinski, Sandrine Juillaguet
Abstract: This paper presents a comparative optical and vibrational spectroscopy study of diversely n-type 4H-SiC epilayers. It is shown that in order to determine the nitrogen doping in a wide range (1016 up to few 1019cm-3) the two techniques are complementary. Moreover only the LTPL provides the information about the compensation and nature of the dopant species.
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