Here, 250nm-thick AlN layers without a nucleation layer were grown directly onto

6H-SiC(00•1) with 3-bilayer-height steps by rf-plasma-assisted molecular-beam

epitaxy. The structure and morphology of the AlN layers were studied using atomic

force microscopy, X-ray diffraction and transmission electron microscopy. Two

different types of unique defect structure were observed. Rows of pure edge-type

threading dislocations were observed along the pre-existing step-edges of the SiC

substrate for AlN grown onto as-gas-etched SiC substrates, while planar defects

threading through the AlN layer were observed at the step-edges of the substrate

for AlN on SiC with sacrificial oxidation. It was concluded that these planar

defects were stacking mismatch boundaries due to the difference in stacking

sequence of AlN layers on different SiC terraces.

Observation of Novel Defect Structure in 2H-AlN Grown on 6H-SiC(0001)

Substrates with 3-Bilayer-Height Step-and-Terrace Structures. H.Okumura,

M.Horita, T.Kimoto, J.Suda: Physica Status Solidi A, 2009, 206[6], 1187-9