Plasma induced microstructural, compositional, and resistivity changes in ultrathin chemical vapor deposited titanium nitride films

R. Kröger*, M. Eizenberg, C. Marcadal, L. Chen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

Extremely thin titanium nitride (TiN) barrier layers for Cu based interconnects were deposited using metal organic chemical vapor deposition. The effect of the subsequently performed nitrogen/hydrogen plasma treatment on the microstructure, composition, and electrical properties of these films is studied using conventional and high resolution transmission electron microscopy, Auger electron spectroscopy, and four point probe resistivity measurements. In the studied system the crystallization of the TiN film starts from an amorphous matrix and a polycrystalline morphology is developed upon the H 2/N 2 plasma treatment. After a short plasma treatment, most of the film is already crystalline and consists of grains of a few nanometers in diameter. Continued plasma treatment leads to grain growth and a significant reduction of contaminants such as oxygen and carbon. The resistivity of the films drops with plasma treatment time, and a correlation between resistivity and oxygen content is found, which suggests that oxygen in the grain boundaries plays a decisive role for the resistivity of the films. It is shown that the oxygen in the grain boundaries leads to an electron reflectance of 0.9. Thus, the oxygen accumulation in the grain boundaries is the limiting factor for the reduction of film resistivity by plasma treatment.

Original languageEnglish
Pages (from-to)5149-5154
Number of pages6
JournalJournal of Applied Physics
Volume91
Issue number8
DOIs
StatePublished - 15 Apr 2002
Externally publishedYes

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