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Thick (111) oriented β-SiC layers have been grown by hetero-epitaxy on a (0001) a-SiC substrate with the Continuous Feed-Physical Vapour Transport (CF-PVT) method. The growth rate was 68 µm/h at a pressure of 2 torr and a temperature of 1950°C. The nucleation step of the β-SiC layer during the heating up of the process was studied in order to manage first the a to b heteropolytypic transition and second the selection of the b-SiC orientation. With a adapted seeding stage, we grew a 0.4mm thick layer almost free of Double Positioning Boundaries on a 30mm diameter sample. First observations of the layer by cross-polarised optical Microscopy are presented both in planar view and in cross section geometry.

In the classical sublimation growth of silicon carbide (SiC) single crystals, the supersaturation in the surrounding of the seed is mainly controlled by pressure and temperature distributions within the growth cavity. Precise control of the supersaturation is difficult, especially if it needs to be adjusted during the process. In the first part of the paper, an experimental study performed in a continuous feed-physical vapor transport reactor (CF-PVT) is shown. This process combines CVD for the feeding of the SiC source and PVT for the growth of the single crystal. It is shown that the feeding gas flow rate (TMS diluted in argon) and/or the temperature allow precise control of the supersaturation close to the seed, much more easily than in the classical sublimation process. In the second part of the paper, the application of the supersaturation control to SiC polytype engineering is demonstrated.

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