Flat-band voltage study of atomic-layer-deposited aluminum-oxide subjected to spike thermal annealing

V. R. Mehta, A. T. Fiory, N. M. Ravindra, M. Y. Ho, G. D. Wilk, T. W. Sorsch

Research output: Contribution to journalConference articlepeer-review

1 Scopus citations

Abstract

High-κ dielectrics based the oxide of Al were prepared by atomic layer deposition (ALD) on 200-mm p-type Si wafers. Films were deposited directly on clean Si or on 0.5-nm underlayers of rapid thermal oxide or oxynitrides grown in O2 and/or NO ambients. The purpose of the underlayer films is to provide a barrier for atomic diffusion from the crystal Si to high-κ dielectric film. Deposited Al-oxide films varied in thickness from 2 to 6 nm. Post deposition anneals were used to stabilize the ALD oxides. Equivalent SiO2-oxide thickness varied from 1.0 to 3.5 nm. In situ P-doped amorphous-Si 160 nm films were deposited over the oxides to prepare heavily doped n-type gate electrodes in MOS structures. Samples were rapid thermal annealed in N2 ambient at 800°C for 30 s, or spike annealed at 950, 1000, and 1050°C (nominally zero time at peak temperature). Flat band voltages, VFB were determined from C-V measurements on dot patterns. The 800°C anneals were used as a baseline, at which the poly-Si electrodes are crystallized and acquire electrical activation while subjecting the high-κ dielectrics to a low thermal budget. Positive shifts in VFB were observed, relative to a pure SiO2 control, ranging from 0.2 to 0.8 V. Spike annealing reduces the VFB shift for ALD films deposited over underlayer films. The VFB shift and the changes with annealing temperature show systematic dependence on the nitridation of the underlayer.

Original languageEnglish (US)
Pages (from-to)109-113
Number of pages5
JournalMaterials Research Society Symposium - Proceedings
Volume765
DOIs
StatePublished - Jan 1 2003
EventMATERIALS RESEARCH SOCIETY SYMPOSIUM PROCEEDINGS CMOS Front-End Materials and Process Technology - San Francisco, CA, United States
Duration: Apr 22 2003Apr 24 2003

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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