Impact of in situ NH3 preannealing on sub-100 nm tungsten polymetal gate electrode during the sealing nitride formation

Kwan Yong Lim, Jung Ho Lee, Heung Jae Cho, Jae Geun Oh, Byung Seop Hong, Se Aug Jang, Yong Soo Kim, Hong Seon Yang, Hyun Chul Sohn

Research output: Contribution to journalArticle

Abstract

We investigated the effects of in situ NH3 preannealing immediately before sealing nitride deposition on the wordline sheet resistance (Rs) of a tungsten polymetal gate electrode (W/WNx/poly- Si). While in situ NH3 preannealing is very effective for the suppression of W-O whisker formation, it was found that excessively long-time NH3 preannealing could cause an unexpectedly abnormal increase in the wordline Rs of short gate length electrodes, typically < 100 nm. Since X-ray diffraction (XRD) and secondary ion mass spectroscopy (SIMS) analyses reveal that long-time NH3 preannealing results in the nitridation of tungsten sidewall surfaces, the wordline Rs increase in a small-gate-length sample subjected to long-time NH3 preannealing is mainly due to tungsten sidewall nitridation, which is localized at the surface region of the tungsten sidewall. In addition, at a long-time NH 3-preannealed gate electrode, an abnormal inflation of the tungsten sidewall occurred due to a slight increment in lattice spacing by tungsten nitridation.

Original languageEnglish
Pages (from-to)1829-1832
Number of pages4
JournalJapanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers
Volume43
Issue number4 B
DOIs
Publication statusPublished - 2004 Apr

All Science Journal Classification (ASJC) codes

  • Engineering(all)
  • Physics and Astronomy(all)

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