Atomic probe microscopy of 3C SiC films grown on 6H SiC substrates

The surface of 3C SiC films grown on 6H SiC substrates has been studied by atomic probe microscopy in air. Atomic-scale images of the 3C SiC surface have been obtained by scanning tunneling microscopy (STM). STM has confirmed the 〈111〉 orientation of the cubic 3C layer grown on the {0001} surface of the hexagonal 6H substrate. The nearest-neighbor atomic spacing for the 3C layer has been measured to be 3.29±0.2 Å, which is within 7% of the bulk value. Shallow terraces in the 3C layer have been observed by STM to separate regions of very smooth growth in the vicinity of the 3C nucleation point from considerably rougher 3C surface regions. These terraces are oriented at right angles to the growth direction. Atomic force microscopy has been used to study etch pits present on the 6H substrate due to high temperature HCl cleaning prior to chemical vapor deposition growth of the 3C layer. The etch pits have hexagonal symmetry and vary in depth from 50 nm to 1 μm.