Novel Pre-silicide Ion-implanted Impurity for N-type Si Contacts

Abstract

This work reports on the Schottky barrier height (SBH) modulation of various impurities on n‐type Si. Elements are selected from groups of lanthanide, chalcogen, and halogen implanted into silicon using conventional ion implantation method prior to nickel silicidation. The effects of incorporating such impurities are examined in terms of their Schottky barrier height modulation, silicide sheet resistance, and thermal stability. Significant Schottky barrier modulation is observed when impurities are incorporated, enabling the improvement of n‐contacts with nickel silicides. Preliminary results of various pre‐silicide impurity implants show SBH modulation to 0.25 eV using a low dose of Yb impurity (dose ∼1×1013/cm2). Impurity‐implanted NiSi is thus shown to have a SBH almost comparable to rare earth silicides but with less process complexity.