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The growth rate of 4H-SiC epi layers has been increased up to 100 OEºm/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. ¬© (2009) Trans Tech Publications, Switzerland.

A process has been developed to grow multi-epy high doped structure. Trichlorosilane (TCS) and Ethylene have been used as precursor; Nitrogen (N 2) 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. © (2009) Trans Tech Publications, Switzerland.

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. © (2009) Trans Tech Publications, Switzerland.

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 and . 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. ¬© (2009) Trans Tech Publications, Switzerland.

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.

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.

The growth rate of 4H-SiC epi layers has been increased by a factor 19 (up to 112 µm/h) with respect to the standard process with the introduction of HCl in the deposition chamber. The epitaxial layers grown with the addition of HCl have been characterized by electrical, optical and structural characterization methods. An optimized process without the addition of HCl is reported for comparison. The Schottky diodes, manufactured on the epitaxial layer grown with the addition of HCl at 1600 °C, have electrical characteristics comparable with the standard epitaxial process with the advantage of an epitaxial growth rate three times higher.

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.

The introduction of hydrogen chloride (HCl) in the deposition chamber during the growth of 4H-SiC epitaxial layers allows very high growth rates to be achieved. The properties of the epilayers and the growth rate depend on many parameters such as the growth temperature and the C/Si, Cl/Si, and Si/H-2 ratios. We have used optical and electrical measurements to investigate the effect of the Cl/Si and Si/H-2 ratio and growth temperature on the epitaxial growth process. The growth rate increases with increasing Si/H-2 ratio and higher growth rates are obtained when HCl is added to the gas flow. Optical microscopy shows an improvement of the surface morphology, and luminescence measurements reveal a decrease in the concentration of complex defects with increasing Cl/Si ratio in the range of 0.05-2.0 and with increasing growth temperature from 1550 degrees C to 1650 degrees C. The electrical measurements on the diodes realized on these epitaxial layers show a decrease of the leakage current with increasing Cl/Si ratio and growth temperature over the same range. Deep level transient spectroscopy measurements indicate that the deep level EH6/7, which is one of the main levels responsible for the high value of leakage current measured in the Schottky diodes, is greatly reduced using HCl as a growth additive.

This paper presents a new compliance substrate for heteroepitaxial growth of OE

The transition from Schottky to ohmic contact in the nickel silicide /SiC system during annealing from 600 to 950 °C was investigated by measuring the electrical properties of the contact and by analyzing the microstructure of the silicide /SiC interface. The graphite clusters formed by carbon atoms during silicidation are uniformly distributed into the silicide layer after annealing at 600 °C and they agglomerate into a thin layer far from the silicide /SiC interface after annealing at 950 °C. At this temperature an increase of the Schottky barrier height was measured, while deep level transient spectroscopy evidences the absence of the 0.5 eV peak related to the carbon vacancies.

Sixteen patients with RA (3 males, 13 females), diagnosed according to RA revised criteria, were selected and entered the study. They underwent six intra-articular injections of 750 mcg of SST14 at 15-day intervals. The thickness of the synovial membrane (SM) was measured with a 5-MHz linear sound with longitudinal and transversal scanning carried out on the upper patellar cavity. The contralateral knee was also assessed together with the injected knee in order to ascertain any systemic effect of the drug. A significant reduction of SM thickness was observed already at the first control (T3) in 14 out of 16 patients. At the 5th and 6th injections (T5 and T6) the reduction was still significant but to a lower extent. In 8 out of 16 cases a reduction of SM thickness was observed in the contralateral knee. Analysis of these data clearly shows that the intra-articular injection of SST14 is able to reduce the thickness of SM in patients with RA, and indicates that SST14 may directly reduce synovitis. This particularity has been detected in our work with a non-invasive technique such as the joint ultra-sound (US). In conclusion, our work confirms the efficacy of SST14 in the control of RA synovial hypertrophy and the reliability of US technique in the measurement of SM thickness.

Deep-Level Transient Spectroscopy (DLTS) and Low Temperature Photholuminescence (LTPL) were used to characterize the defects introduced in 6H-SiC epitaxial layer by 2.5 MeV He+ irradiation and their behaviour with thermal annealing in the temperature range 200 - 900 degreesC. The DLTS spectra of as irradiated sample show different levels at an energy of 0.40 eV (E-1/E-2), 0.51 eV (RD5) and 0.71 eV (Z(1)/Z(2)) from the bottom of the conduction band. The concentration of the E-1/E-2 level increases with annealing temperature, while the concentration of the remaining peaks decreases. The LTPL of the irradiated sample shows a series of sharp peaks and broad bands in the region 470-500 nm. A set of peaks (473-479 nm) related to carbon vacancies anneals at 600 degreesC, a second set (470 nm) is stable up to 900 degreesC and a third set (L-1-473 nm. and L-2-480 nm) anneals starting from 400 degreesC. The comparison of both measurements suggests that the Z(1)/Z(2) (0.71 eV) DLTS level and the L-1 (L-2) luminescence peaks can be related to the same defect center.