Thermal Stability of Nickel Silicide and Shallow Junction Electrical Characteristics with Carbon Ion Implantation

In this work, we investigated the impact of carbon ion implantation on the thermal stability of nickel silicide film and nickel-silicide-contact n+/p shallow junctions. A higher carbon ion implantation dose can prevent the nickel silicide film from agglomeration and phase transformation. However, good thermal stability does not necessarily lead to excellent junction current--voltage characteristics owing to the diffusion of nickel atoms. When the carbon ion implantation dose increases to $5\times 10^{15}$ cm-2, many crystal defects are created. Then, numerous nickel atoms diffuse along these defects into the junction depletion region during the silicide formation process, resulting in poor junction characteristics. The trade-off between thermal stability and junction electrical characteristics is discussed in this paper. Finally, two methods are suggested to solve the serious leakage current problem.