Direct Epitaxial Nanometer-Thin InN of High Structural Quality on 4H-SiC by Atomic Layer Deposition

Indium nitride (InN) is a highly promising material for high frequency electronics given its
low band gap and high electron mobility. The development of InN-based devices is hampered
by the limitations in depositing very thin InN films of high quality. We demonstrate growth of
high-structural-quality nanometer thin InN films on 4H-SiC by atomic layer deposition (ALD).
High resolution X-ray diffraction and transmission electron microscopy show epitaxial growth
and an atomically sharp interface between InN and 4H-SiC. The InN film is fully relaxed already after a few atomic layers and shows a very smooth morphology where the low surface
roughness (0.14 nm) is found to reproduced sub-nanometer surface features of the substrate. Raman measurements show an asymmetric broadening caused by grains in the InN film. Our results show the potential of ALD to prepare high quality nanometer-thin InN films for subsequent formation of heterojunctions.