Epitaxial Growth Of Al-cr-n Thin Films On Mgo(111)

摘要

Cubic rock salt structure Al_(0.60)Cr_(0.40)N and Al_(0.68)Cr_(0.32)NN films of different thicknesses were grown epitaxially onto MgO(111) substrates by reactive unbalanced magnetron sputtering at 500 ℃. Rutherford backscattering spectroscopy reveals stoichiometric nitrides with Al/Cr ratios close to the ones of the used compound targets of 60/40 and 70/30. High resolution X-ray diffraction proves epitaxial growth over the whole film thickness up to thicknesses of ～ 1.8 μm. Reciprocal space maps and selected area electron diffraction show that the Al_xCr_(1-x)N films grow fully relaxed. Scanning and transmission electron microscopy imaging reveals columnar microstructures with column widths between 12-16 nm and {001} surface faceting on individual columns. The fully relaxed growth and the columnar structure can be attributed to limited ad-atom mobility on the initial Al_xCr_(1-x)N(111) growth surface.