Pt hillock formation and decay

Scott R. Summerfelt*, Dave Kotecki, Angus Kingon, H. N. Al-Shareef

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

24 Scopus citations

Abstract

The formation of Pt hillocks during high temperature processing is a problem when using Pt as a bottom electrode for high dielectric constant materials. The hillock height is frequently larger than the dielectric thickness, degrading the leakage current of the device. In this work, Pt was deposited by electron beam evaporation on in-situ formed 40 nm ZrO2 coated SiO2/Si substrates. The samples were then annealed at temperatures between 400 °C and 700 °C for times ranging from 2 min to 40 min. The surface roughness was measured by atomic force microscopy (AFM). The surface was characterized using Ra, RMS and Zmax over 5 μm×5 μm regions. Zmax is sensitive to hillock formation and Ra is sensitive to changes in general surface roughness. Analysis of Zmax indicates that 100 nm Pt/ZrO2 deposited at 315 °C forms hillocks above 450 °C during initial heatup. Subsequently, the hillocks decay for temperatures of 600 °C and above such that they are almost gone after a 30 min air anneal. In-situ wafer stress measurements of Pt/ZrO2 were performed in O2 at temperatures up to 650 °C. The Pt relaxes above 500 °C in O2.

Original languageEnglish (US)
Pages (from-to)257-262
Number of pages6
JournalMaterials Research Society Symposium - Proceedings
Volume361
StatePublished - 1995
Externally publishedYes

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials

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