The Process Window of a-Si/Ti Bilayer Metallization for an Oxidation-Resistant and Self-Aligned TiSi2 Process

Yung Song Lou, Ching Yuan Wu, Huang-Chung Cheng

Research output: Contribution to journalArticle

7 Scopus citations

Abstract

The dependences of both oxidation-resistant and self-aligned silicidation properties on the thicknesses of top amorphous-Si (a-Si) and Ti metal in an a-Si/Ti bilayer process are presented. It is shown that a thin silicide layer formed during the reaction between a-Si and Ti films becomes a stable oxidation and nitridation barrier for oxygen- and nitrogen-related impurities. Moreover, the formation sequence of the silicide phase depends on not only the annealing temperature but also the thickness of Ti film. In addition, the preferential orientation of the silicide phase after annealing at high temperature also shows a strong dependence of the thickness of Ti film, which is attributed to the difference of the grain size in the polycrystalline silicide film. The allowed process window for the a-Si thickness can be determined experimentally and a reproducible and homogeneous self-aligned TiSi2 film can be easily obtained by using the a-Si/Ti bilayer process in SALICIDE applications despite of high-level contaminations of oxygen impurities in both the as-deposited Ti film and the annealing ambient.

Original languageEnglish
Pages (from-to)1835-1843
Number of pages9
JournalIEEE Transactions on Electron Devices
Volume39
Issue number8
DOIs
StatePublished - 1 Jan 1992

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