Papers by Author: Giuseppe Condorelli

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Authors: Giuseppe D'Arrigo, Andrea Severino, G. Milazzo, Corrado Bongiorno, Nicolò Piluso, Giuseppe Abbondanza, Marco Mauceri, Giuseppe Condorelli, Francesco La Via
Abstract: 3C-SiC devices are hampered by the defect density in heteroepitaxial films. Acting on the substrate, it is possible to achieve a better compliance between Si and 3C-SiC. We present here an approach to favorite defect geometrical reduction in both [ ] and [ ] directions by creating Inverted Silicon Pyramids (ISP). A study of 3C-SiC growth on ISP is reported showing benefits in the film quality and a reduction in the linear density of stacking faults. Growth on ISP leads also to a decrease in the 3C-SiC residual stress as well as in the bow of the Si/SiC system.
Authors: Ruggero Anzalone, Andrea Severino, Giuseppe D'Arrigo, Corrado Bongiorno, Patrick Fiorenza, Gaetano Foti, Giuseppe Condorelli, Marco Mauceri, Giuseppe Abbondanza, Francesco La Via
Abstract: The aim of this work is to improve the heteroepitaxial growth process of 3C-SiC on Si substrates using Trichlorosilane (SiHCl3) as the silicon growth precursor. With this precursor it has been shown that it is possible to simultaneously increase the growth rate of the process and avoid the nucleation of silicon droplets in the gas phase. Growth experiments were conducted on three (3) Si substrate orientations in order to assess the impact of the Si substrate on the resulting 3C-SiC film. X-ray Diffraction (XRD), Atomic Force Microscopy (AFM) and Transmission Electron Microscopy (TEM) analysis show the important role of the substrate orientation for the growth process. The different orientation of the substrate modifies the morphology of the 3C-SiC crystalline structure, mostly by changing the density of micro-twins and stacking faults inside the film.
Authors: Andrea Severino, Massimo Camarda, Nicolò Piluso, M. Italia, Giuseppe Condorelli, Marco Mauceri, Giuseppe Abbondanza, Francesco La Via
Abstract: Growth of 3C-SiC films on an off-axis (111) Si substrate, with a miscut of 4° towards the <110> direction, is here reported. An extensive material characterization has been conducted by means of Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), X-Ray Diffraction (XRD) and Raman spectroscopy, indicating a very promising film quality with extremely flat surface and interface. Notwithstanding the excellent film quality, the wafer bow is still limiting its full employment in device realization.
Authors: Andrea Severino, Corrado Bongiorno, Stefano Leone, Marco Mauceri, Giuseppe Pistone, Giuseppe Condorelli, Giuseppe Abbondanza, F. Portuese, Gaetano Foti, Francesco La Via
Abstract: 3C-SiC/Si heteroepitaxy is hampered by large mismatches in lattice parameters (19.7%) and thermal expansion coefficient (8%) leading to 3C-SiC films containing high defects density. To reduce the presence of defects, a multi-step growth process in a CVD reactor is used. The aim of the work is to study the effect of carbonization on differently oriented Si surfaces, experiencing a 200°C-wide temperature range in a CVD reactor, to improve the crystalline quality. TEM analysis are carried out to evaluate thickness, crystal orientations and defects of carbonized layers with respect to the time-dependence of the process and to the different orientations of the Si substrate. It will be shown that process-related defects are strictly correlated to the substrate orientation either for size, density, occupied area, shape or thickness. Uniform, flat and crystalline thin SiC films are obtained with a low defect density.
Authors: Maurizio Masi, Alessandro Veneroni, A. Fiorucci, Francesco La Via, Gaetano Foti, Marco Mauceri, Stefano Leone, Giuseppe Pistone, Giuseppe Condorelli, Giuseppe Abbondanza, Gian Luca Valente, Danilo Crippa
Abstract: A simplified deposition model, involving both the description of the deposition and of the film morphology was adopted to quantitatively understand the experimental trends encountered in the epitaxial silicon carbide deposition in an industrial hot wall reactor. The attention was focused on the system involving chlorinated species because its really superior performances with respect the traditional silane/hydrocarbons process. The evolution of the crystalline structure (i.e., from poly to single) and of the surface roughness can be understood by simply comparing two characteristic times, like those inherent the surface diffusion and the matter supply to the surface.
Authors: Lucia Calcagno, Gaetano Izzo, Grazia Litrico, G. Galvagno, A. Firrincieli, Salvatore di Franco, Marco Mauceri, Stefano Leone, Giuseppe Pistone, Giuseppe Condorelli, F. Portuese, Giuseppe Abbondanza, Gaetano Foti, Francesco La Via
Abstract: High growth rate of 4H-SiC epitaxial layers can be reached with the introduction of HCl in the deposition chamber. The effect of the Cl/Si ratio on this epitaxial growth process has been studied by optical and electrical measurements. Optical microscopy shows an improvement of the surface morphology and luminescence measurements reveal a decrease of epitaxial layer defects with increasing the Cl/Si ratio in the range 0.05–2.0. The leakage current measured on the diodes realized on these wafers is reduced of an order of magnitude and DLTS measurements show a decrease of the EH6,7 level concentration in the same range of Cl/Si ratio. The value Cl/Si=2.0 allows to grow epitaxial layers with the lowest defect concentration.
Authors: Nicolò Piluso, Andrea Severino, Massimo Camarda, Ruggero Anzalone, Andrea Canino, Giuseppe Condorelli, Giuseppe Abbondanza, Francesco La Via
Abstract: Raman microscopy has been used to study transport properties in hetero-epitaxial 3C-SiC/Si thin films. By an accurate analysis of the Longitudinal Optic phonon-plasmon coupled (LOPC) modes in n-type doped 3C-SiC films, free carrier density and mobility has been determined. A study of doped 3C-SiC reveals a strong relationship between the calculated free carrier density and both the C/Si ratio used during the epitaxial process and Silicon substrates orientation on which 3C-SiC thin films were grown (maintaining the N2 gas flow rate). The free carrier density obtained is in the range between 5x1016 cm-3 and 4x1018 cm-3. Epitaxial films grown on (111) Si substrates show a higher free carrier density and a lower dependence on C/Si ratios as compared to films grown on (100) Si substrates.
Authors: Francesco La Via, Gaetano Izzo, Marco Mauceri, Giuseppe Pistone, Giuseppe Condorelli, L.M.S. Perdicaro, Giuseppe Abbondanza, F. Portuese, G. Galvagno, Salvatore di Franco, Lucia Calcagno, Gaetano Foti, Gian Luca Valente, Danilo Crippa
Abstract: The growth rate of 4H-SiC epi layers has been increased up to 100 µm/h with the use of trichlorosilane instead of silane as silicon precursor. The epitaxial layers grown with this process have been characterized by electrical, optical and structural characterization methods. Schottky diodes, manufactured on the epitaxial layer grown with trichlorosilane at 1600 °C, have higher yield and lower defect density in comparison to diodes realized on epilayers grown with the standard epitaxial process.
Authors: Giuseppe Condorelli, Marco Mauceri, Giuseppe Pistone, L.M.S. Perdicaro, Giuseppe Abbondanza, F. Portuese, Gian Luca Valente, Danilo Crippa, Filippo Giannazzo, Francesco La Via
Abstract: A process has been developed to grow multi-epy high doped structure. Trichlorosilane (TCS) and Ethylene have been used as precursor; Nitrogen (N2) and trimethylaluminum (TMA) as doping source. The SIMS and SCM analysis show that using this silicon precursor very abrupt N++/P+/N+ junctions (40-60 nm) can be obtained with low background doping concentration in a single epitaxial growth run.
Authors: Andrea Severino, Ruggero Anzalone, Corrado Bongiorno, M. Italia, Giuseppe Abbondanza, Massimo Camarda, L.M.S. Perdicaro, Giuseppe Condorelli, Marco Mauceri, Francesco La Via
Abstract: The choice of off-axis (111) Si substrates is poorly reported in literature despite of the ability of such an oriented Si substrate in the reduction of stacking faults generation and propagation. The introduction of off-axis surface would be relevant for the suppression of incoherent boundaries. We grew 3C-SiC films on (111) Si substrates with a miscut angle from 3° to 6° along <110> and <11 >. The film quality was proved to be high by X-Ray diffraction (XRD) characterization. Transmission electron microscopy was performed to give an evaluation of the stacking fault density while pole figures were conducted to detect microtwins. Good quality single crystal 3C-SiC films were finally grown on 6 inch off-axis (111)Si substrate. The generated stress on both 2 and 6 inch 3C-SiC wafers has been analyzed and discussed.
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