Structural defects in 3C-SiC grown on Si by supersonic jet epitaxy

3C-SiC thin films have been grown on Si(001) and Si(111) substrates by supersonic jet epitaxy. Cross-sectional high resolution scanning transmission electron microscopy (STEM) is used to study the SiC/Si interface structure and defects in the films. The occurrence of twins is evident in the selected area electron diffraction pattern taken from a SiC/Si(111) heterostructure. A 39 degrees angle between twinned and untwinned {111} planes in the [1 (1) over bar 0] projection is confirmed by x-ray pole figure. Twinning is attributed to the growth on the {111} planes. Pure edge misfit dislocations are found at the interface to accommodate the extreme lattice mismatch in SiC/Si(001) heterostructures. A schematic model of the STEM image reveals that a pair of 60 degrees dislocations intersect to form an edge misfit dislocation. A large number of stacking faults and microtwins are present in SiC thin films grown on both Si(001) and Si(111) substrates. The formation of planar defects is attributed to the coalescence of individual three-dimensional islands. Possible methods for the reduction of the planar defects are discussed. (C) 1999 American Institute of Physics. [S0021-8979(99)02817-0].