Impacts of Ge Preamorphization Implantation and Si Capping on the Specific Contact Resistivity of Ni(Pt)SiGe/p+-SiGe Contacts

Abstract

This article explores the impacts of both Ge preamorphization implantation (PAI) and Si capping on the specific contact resistivity ( $\rho _{c}$ ) of Ni(Pt)SiGe/p+-SiGe contacts elaborately. Both Ge PAI and Si capping are found to be beneficial in reducing the $\rho _{c}$ of Ni(Pt)SiGe/p+-SiGe contacts remarkably, with $\rho _{c}$ values reduced from the original ${20.03} \times {10}^{-{8}} \Omega $ -cm2 to ${9.92} \times {10}^{-{8}}\,\,\Omega $ -cm2 with Ge PAI and ${1.44} \times {10}^{-{8}} \Omega $ -cm2 with Si capping, respectively. Improved interfacial uniformity and morphology are thought to be primarily responsible for such significant reductions in $\rho _{c}$ since neither Ge PAI nor Si capping induces an obvious difference in B concentrations at the interface of Ni(Pt)SiGe/p+-SiGe. Moreover, by combining Ge PAI or Si capping with extra B implantation before germanosilicidation to intentionally introduce B dopant segregation (DS) at the interface of Ni(Pt)SiGe/p+-SiGe contacts, further reduction of $\rho _{c}$ values is accomplished as anticipated.