Papers by Author: Gabriel Ferro

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Authors: Tony Abi-Tannous, Maher Soueidan, Gabriel Ferro, Mihai Lazar, Berangère Toury, Marie France Beaufort, Jean François Barbot, J. Penuelas, Dominique Planson
Abstract: In order to form Ti3SiC2 on 4H-SiC(0001) 8°-off, 200 nm of Ti30Al70 was deposited onto SiC substrates by magnetron sputtering from pure Ti30Al70 targets. The samples were then annealed at 1000°C for 10 min under Ar atmosphere in a Rapid Thermal Annealing (RTA) furnace. Structural analyses reveal the formation of epitaxial hexagonal Ti3SiC2 (0001) oriented. Elemental analyses show that high amount of Al and O elements are present inside the deposit. Obviously, the formation of Ti3SiC2 is accompanied by parasitic Al oxide, probably due to some unwanted oxygen residual in the RTA chamber. By using proper backing steps before the annealing, the deposit is not anymore composed of only Ti3SiC2 but accompanied with other compounds (Al3Ti, and Al). On the oxide-free sample, the specific contact resistance ρc of the Ti3SiC2 based contact on p-type 4H-SiC (having Na= 2×1019 cm-3) was measured to be as low as 6×10-5 Ω.cm2.
Authors: Jean Lorenzzi, Nikoletta Jegenyes, Mihai Lazar, Dominique Tournier, Davy Carole, François Cauwet, Gabriel Ferro
Abstract: In this work we report on the study of twin boundary (TB) evolution during heteroepitaxial growth of 3C-SiC on patterned 4H-SiC(0001) substrate by vapour-liquid-solid (VLS) mechanism. Ge50Si50 melt was used at a temperature of 1450°C. 3C-SiC deposit was obtained on top and outside the mesas. Some lateral enlargement of these mesas was observed but it was systematically homoepitaxial. Elimination of TBs inside the 3C-SiC deposit on top of the mesas was observed for specific mesa shape and/or orientation of the sidewalls. Though three–fold or six-fold symmetry mesas are recommended for TB elimination, originally circular mesas lead also to the same result due to initial faceting toward hexagonal shape.
Authors: Gabriel Ferro
Abstract: In this paper, the issues related to in-situ doping of silicon carbide (SiC) semiconductor during epitaxial growth are reviewed. Some of these issues can find solution by using an original approach called vapour-liquid-solid (VLS) mechanism. In this technique, the SiC seed is covered by a Sibased melt and is fed by propane in order to growth the epitaxial film. Using Al-Si melts and temperatures as low as 1100°C, very high p type doping was demonstrated, with a record value of 1.1021 It leads to very low contact resistivity and even to metallic behaviour of the SiC deposit even at low temperature. Using Ge-Si melts, non intentionally low doped n type layers are grown. By forming Si-containing liquid droplets on a SiC seed, one can extrapolate this VLS growth to selective epitaxial growth (SEG). Such approach was successfully applied for both Al and Ge-based systems in order to form p+ and n doped areas respectively.
Authors: Patrik Ščajev, Pavels Onufrijevs, Georgios Manolis, Mindaugas Karaliūnas, Saulius Nargelas, Nikoletta Jegenyes, Jean Lorenzzi, Gabriel Ferro, Milena Beshkova, Remigijus Vasiliauskas, Mikael Syväjärvi, Rositza Yakimova, Masashi Kato, Kęstutis Jarašiūnas
Abstract: We applied a number of time-resolved optical techniques for investigation of optical and photoelectrical properties of cubic SiC grown by different technologies on different substrates. The excess carriers were injected by a short laser pulse and their dynamics was monitored by free-carrier absorption, light-induced transient grating, and photoluminescence techniques in a wide excitation range. Combining an optical and electrical probe beam delay, we found that free carrier lifetimes in differently grown layers vary from few ns up to 20 μs. Temperature dependences of carrier diffusivity and lifetime revealed a pronounced carrier trapping in thin sublimation grown layers. In free-standing layers and thick sublimation layers, the ambipolar mobility was found the highest (120 cm2/Vs at room temperature). A linear correlation between the room-temperature band edge emission and carrier lifetime in differently grown layers was attributed to defect density, strongly dependent on the used growth conditions.
Authors: Ghassan Younes, Maher Soueidan, Gabriel Ferro, Khaled Zahraman, Bilal Nsouli
Abstract: In this work the capability of the proton induced X-ray emission (PIXE) technique to monitor a rapid, non-destructive and accurate quantification of Al on or inside SiC is discussed. Optimization of PIXE acquisition parameters was performed using as reference, a thin Al film (2.5 nm) thermally evaporated onto silicon carbide substrate. In order to improve the sensitivity for Al detection and quantitative determination, a systematic study was undertaken using proton ion beam at different energies (from 0.2 to 3 MeV) with a different tilting angle (0°, 60°, and 80°). The limit of detection (LOD) was found to be lower than 0.02 nm. The optimum PIXE conditions (energy, angle) were applied for determining the Al doping concentration in thin (1 µm) 4H-SiC homoepitaxial layer. The Al concentration as determined by PIXE was found to be 3.9x1020 at/cm3 in good agreement with SIMS measurements, and the LOD was estimated to be 6x1018 at/cm3.
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