THE ORIGIN OF 3C POLYTYPE INCLUSIONS IN EPITAXIAL LAYERS OF SILICON-CARBIDE GROWN BY CHEMICAL-VAPOR-DEPOSITION

Formation of 3C silicon carbide (SiC) inclusions in 4H SiC epitaxial l ayers has been investigated using defect revealing techniques and tran smission electron microscopy. The nucleation mechanism of 3C is shown to relate to the formation of triangular stacking faults (TSFs) induce d by substrate imperfections and surface defects. The TSFs modify the surface morphology by forming large (0001) surface terraces, A high lo cal supersaturation at the TSF regions results in the spontaneous nucl eation of 3C, in a manner similar to that which occurs on on-axis SiC substrates. Depending on the defect that gives rise to the TSF, the 3C inclusions may be completely overgrown by 4H polytype only leaving a striation at the edge. (C) 1997 Elsevier Science S.A.