Controllable fabrication of amorphous Si layer by energetic cluster ion bombardment

• Energetic C60 cluster ion impacts on Si(100) creates amorphous Si surface layer.
• Thickness of amorphous Si layer is controlled by energy of C60 cluster ions.
• Structure of modified Si layer elucidates main effects induced by cluster impact.

We report on the fabrication of an amorphous Si (a-Si) thin layer by means of bombardment of a Si(100) surface using monoenergetic C60 cluster ions with energies from 50 keV to 400 keV. The C60 cluster implantation produces nanogranules on the surface of a-Si layer detected by atomic force microscopy. The structural disorder and thickness of the modified layer were identified using Raman spectrometry, ion channelling, spectroscopic ellipsometry (SE) and transmission electron microscopy (TEM). According to SE and TEM data the thickness of a-Si layer gradually increases with cluster ion energy reaching to about 30 nm in the 200 keV C60-bombarded Si sample. There is also thin layer of nanocrystalline Si found between the a-Si layer and pristine Si crystal. The obtained results represent an attractive method for creation of the a-Si layer as a functional material for opto- and nano-electronics. The study describes nanostructure created by cluster ion implantation as well as demonstrates the structural consequences of fast cluster energy dissipation in solids such as local heating and shock waves.