Kinetics and morphological stability in sublimation growth of 6H and 4H SiC epitaxial layers

Very high growth rates (>2 mm h−1) in SiC epitaxy have been achieved. The rate determining mechanism changes from diffusion to kinetics when the growth pressure decreases below 5–10 mbar. At low pressures it is shown that sublimation of the SiC source is the rate determining step and that there is a free molecular transport from source to substrate. The growth rate is constant during several hours of growth and Si losses from the crucible are very small. These facts show that our growth system is stable. The obtained apparent activation energy (130 kcal mol−1) is attributed to the sublimation rate of the SiC source material. The morphology is smooth and the surfaces are specular if the growth conditions are selected within the given parameter window for morphological stability. The origin of the growth disturbances is discussed.