Formation of Si wells and pyramids on (1Â 0Â 0) surface as a result of Zn-Si interaction

Interaction between metallic zinc and Si wafer at moderately high temperatures was found to generate either concave wells or hollow pyramid-shaped protrusions on the (1 0 0) wafer surface. The formation of the wells is attributed to the dissolution of silicon at temperatures much lower than its melting point in the form of Zn-Si eutectic. When the temperature was raised, Zn atoms in the eutectic droplets evaporated and Si atoms in them precipitated accordingly. If a droplet contained plenty of Si atoms, these Si atoms could encounter each other during precipitation at the surface of the droplet and condense into a hollow pyramid-shaped protrusion.