Epitaxy of Ultrathin NiSi2 Films with Predetermined Thickness

This letter presents a proof-of-concept process for tunable, self-limiting growth of ultrathin epitaxial NiSi 2 films on Si (100). The process starts with metal sputter-deposition, followed by wet etching and then silicidation. By ionizing a fraction of the sputtered Ni atoms and biasing the Si substrate, the amount of Ni atoms incorporated in the substrate after wet etching can be controlled. As a result, the thickness of the NiSi 2 films is increased from 4.7 to 7.2 nm by changing the nominal substrate bias from 0 to 600 V. The NiSi 2 films are characterized by a specific resistivity around 50 μ Ω cm.