The growth rate of a 4H-SiC epitaxial layer has been increased by a factor of 19 (up to 112 lm h -1 ) with respect to the standard process, with the introduction of HCl in the deposition chamber. The epitaxial layers grown with the addition of HCl has been characterized by electrical, optical, and structural characterization methods. The effects of various deposition parameters on the epitaxial growth process have been described, and an explanation of this behavior in terms of the diffusion coefficient on the surface, D s , and the ratio between the characteristic times, s D :s G , has been provided. The diodes, manufactured on the epitaxial layer grown with the addition of HCl at 1600°C, have electrical characteristics comparable with the standard epitaxial process. This process is very promising for high-power devices with a breakdown voltage of 10 kV.

The results of a new epitaxial process using an industrial 6x2” wafer reactor with the introduction of HCl during the growth have been reported. A complete reduction of silicon nucleation in the gas phase has been observed even for high silicon dilution parameters (Si/H2>0.05) and an increase of the growth rate until about 20 µm/h has been measured. No difference has been observed in terms of defects, doping uniformity (average maximum variation 8%) and thickness uniformity (average maximum variation 1.2 %) with respect to the standard process without HCl.

4H-SiC epitaxial layers have been grown using trichlorosilane (TCS) as the silicon precursor source together with ethylene as the carbon precursor source. A higher C/Si ratio is necessary compared with the silane/ethylene system. This ratio has to be reduced especially at higher Si/H2 ratio because the step-bunching effect occurs. From the comparison with the process that uses silane as the silicon precursor, a 15% higher growth rate has been found using TCS (trichlorosilane) at the same Si/H2 ratio. Furthermore, in the TCS process, the presence of chlorine, that reduces the possibility of silicon droplet formation, allows to use a high Si/H2 ratio and then to reach high growth rates (16 *m/h). The obtained results on the growth rates, the surface roughness and the crystal quality are very promising.

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.

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.