Anomalous Nickel Silicide Encroachment in n-Channel Metal–Oxide–Semiconductor Field-Effect Transitors on Si(110) Substrates and Its Suppression by Si+ Ion-Implantation Technique

概要

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A novel low-leakage-current nickel self-aligned-silicide (SALICIDE) process in n-channel metal–oxide–semiconductor field-effect transistors (nMOSFETs) on Si(110) substrates is reported. Anomalous nickel silicide encroachment in the $\langle 110\rangle$ direction in nMOSFETs on Si(110) substrates is found for the first time. This encroachment causes anomalous off-state leakage current ($I_{\text{off}}$) in nMOSFETs on Si(110) substrates. In particular, in the case of the $\langle 110\rangle$ channel on Si(110) substrates, Ni atoms easily diffuse in the $\langle 110\rangle$ direction, and nickel silicide preferentially grows in the $\langle 110\rangle$ direction. As a result, anomalous leakage current between the drain and the source occurs, and the leakage current seriously degrades transistor performance. In order to overcome these problems, we propose a method of suppressing anomalous $I_{\text{off}}$ on Si(110) substrates by Si+ ion-implantation technique prior to the nickel SALICIDE process. This method is effective for suppressing the encroachment of nickel silicide and realizing low-leakage complementary metal–oxide–semiconductor (CMOS) devices on Si(110) substrates.
Published by the Japan Society of Applied Physics through the Institute of Pure and Applied Physicsの論文
2009-06-25