Growth of pinhole-free epitaxial Yb and Er silicide thin films on atomically clean (111)Si

The growth of pinhole-free epitaxial Yb and Er silicide thin films on (111)Si has been achieved by capping appropriate amorphous Si(a-Si) layer at room temperature followed by annealing at 700°C in an ultrahigh vacuum chamber. The thickness of the a-Si capping layer was selected to be such that the consumption of Si atoms from the substrate is minimized. The design and reimplementation of the scheme involving appropriate thickness of a-Si capping layer was based on an understanding of the formation mechanism of the pinholes with epitaxial rare-earth islands as diffusion barriers for Si diffusion at the silicide∕Si interfaces.