Journal Article

PreJuSER-31595

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png SrBi 2Ta 2O 9 ferroelectric thin film capacitors: degradation in a hydrogen ambient

Hartner, W. ; Bosk, P. ; Schindler, G. ; Bachhofer, H. ; Mört, M. ; Wendt, H. ; Mikolajick, D. A. B. ; Dehm, C. ; Schroeder, H.FZJ* ; Waser, R.FZJ*

2003
Springer Berlin

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Please use a persistent id in citations: doi:10.1007/s00339-002-1500-y

Abstract: The effects of annealing in forming gas 5% hydrogen, 95% nitrogen; FGA) are studied on spin-coated SrBi2Ta2O9 (SBT) thin films. SBT films on a platinum bottom electrode are characterized with and without a platinum top electrode. Films are characterized by residual stress measurements, scanning electron microscopy (SEM), Auger electron spectroscopy (AES), high-temperature X-ray diffraction (HT-XRD) and secondary ion mass spectrometry (SIMS). To determine the degree of strain, lattice constants of Pt are measured by X-ray diffraction (XRD). HT-XRD of blanket SBT/Pt/Ti films in forming gas revealed that the bismuth-layered perovskite structure of SBT is stable up to approximately 500 degreesC. After formation of an intermediate phase between 550 degreesC and 700 degreesC, SBT changes its structure to an amorphous phase. SIMS analysis of Pt/SBT/Pt samples annealed in deuterated forming gas (5% D-2, 95% N-2) showed that hydrogen accumulates in the SBT layer and at the platinum interfaces next to the SBT. After FGA of blanket SBT films, tall platinum-bismuth whiskers are seen on the SBT surface. It is confirmed that these whiskers originate from the platinum bottom electrode and grow through the SBT layer. FGA of the entire Pt/SBT/Pt/Ti stack shows two different results. For the samples with a high-temperature annealing (HTA) step in oxygen after top electrode patterning, peeling of the top electrode is observed after FGA. For the samples without a HTA step, no peeling is observed after FGA. The residual stress at room temperature is measured for blanket platinum wafers deposited at different temperatures. It is found that an increase in tensile stress caused by the HTA step in oxygen is followed by a decrease in stress caused by the hydrogen in the forming gas. Without HTA, however, an increase of stress is observed after FGA.

Keyword(s): J

Note: Record converted from VDB: 12.11.2012

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Contributing Institute(s):

1. Elektrokeramische Materialien (IFF-EKM)

Research Program(s):

1. Materialien, Prozesse und Bauelemente für die Mikro- und Nanoelektronik (I01)

Appears in the scientific report 2003

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Database coverage:
JCR ; Science Citation Index Expanded ; Thomson Reuters Master Journal List ; Web of Science Core Collection

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