Controlled growth of 15R-SiC single crystals by the modified Lely method

Bulk single crystals of the 15R-polytype of SiC have been grown by the sublimation physical-vapor-transport technique. 15R-SiC crystal growth was stabilized on a 15R-SiC seed using near-thermal-equilibrium growth conditions and a stoichiometric SiC sublimation source material. The polarity of the seed surface is shown to be an important factor in preparation of the 15R-polytype. The dual seed method (simultaneous growth on the Si- and C-face) was employed to demonstrate that 15R-polytype growth occurred only on the Si-face, while 6H- and 4H-polytype growth occurred on the C-face. The incorporation of nitrogen donors and boron accepters was also shown to be a function of seed polarity, with nitrogen incorporation on the C-face two times that on the Si-face, and boron incorporation on the C-face one-half that on the Si-face.