Thermal stability of amorphous-like WNx/W bilayered diffusion barrier for chemical vapor deposited-tungsten/p+-Si contact system

Kow-Ming Chang*, I. Chung Deng, Ta Hsun Yeh, Kuen Der Lain, Chao Ming Fu

*Corresponding author for this work

Research output: Contribution to journalArticle

4 Scopus citations

Abstract

The barrier characteristics of tungsten nitride/tungsten (WNx/W) bilayer formed by an in situ nitridation on a thin chemical vapor deposited amorphous-like tungsten (CVD a-W) film in CVD-W/Si contact system have been investigated. The thickness of WNx layer after a 5 min of N2 plasma exposure at 300°C approximated 50 nm and the atomic ratio of W to N in WNx layer was 2 1. In the CVD-W/a-WNx/a-W/Si multilayered sample, no discernible tungsten suicide was detected by X-ray diffractometer (XRD) at W/Si interface after annealing at 750°C. Meanwhile, with the Rutherford backscattering spectroscopy (RBS) analysis and the measurement of p+n junction leakage current, the CVD-W/a-WNx/a-W/Si multilayer maintained the integrity of interface and the CVD-W/a-WNx/a-W/p+n diode kept the reverse leakage current density less than 9 × 10-9 A/cm2 while the post annealing was carried out at 700°C for 30 min. As the experimental results, the effectiveness of amorphous-like WNx/W bilayered diffusion barrier is attributed to stuff grain boundary with N atoms as well as to eliminate the rapid diffusion paths by using CVD a-W material.

Original languageEnglish
Pages (from-to)1343-1351
Number of pages9
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume38
Issue number3 A
DOIs
StatePublished - 1 Dec 1999

Keywords

  • Bilayer
  • CVD-W
  • Diffusion barrier
  • Gas phase nucleation
  • Nitridation

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