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Hillock Formation in Platinum Films

Published online by Cambridge University Press:  25 February 2011

Philip D. Hren ,
H. Al-Shareef ,
S. H. Rou ,
A. I. Kingon ,
P. Buaud  and
E. A. Irene
Philip D. Hren
Affiliation:
North Carolina State University, Dept. of Materials Science and Engineering, Raleigh, NC 27695–7907
H. Al-Shareef
Affiliation:
North Carolina State University, Dept. of Materials Science and Engineering, Raleigh, NC 27695–7907
S. H. Rou
Affiliation:
North Carolina State University, Dept. of Materials Science and Engineering, Raleigh, NC 27695–7907
A. I. Kingon
Affiliation:
North Carolina State University, Dept. of Materials Science and Engineering, Raleigh, NC 27695–7907
P. Buaud
Affiliation:
University of North Carolina, Department of Chemistry, Chapel Hill, NC 27599–3290
E. A. Irene
Affiliation:
University of North Carolina, Department of Chemistry, Chapel Hill, NC 27599–3290
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Abstract

Hillocks, surface protrusions from thin metal films, have been observed in Al, Al/Cu, Pb, and other materials. Platinum films are widely used as substrates for the deposition of ferroelectric thin films because of their superior oxidation resistance. However, hillock formation in platinum films has not been reported in the literature. In this work, we report the appearance of hillocks in platinum in Pt/Ti bilayers on oxidized silicon wafers. Platinum films 250 to 300 nra were deposited by ion beam sputter deposition at 25°C and 300°C onto a 70 nm Ti film on oxidized Si wafers. The wafers were then heated in flowing argon to 600°C, held 1 hr at 600°C, and cooled to room temperature while the wafer curvature (and hence the film stress) was measured with a laser beam deflection technique. At 600°C, compressive stresses of 0.1 to 0.4 GPa, due to thermal expansion mismatch, developed in the metal films. The platinum surface, initially flat, showed strong hillocking after the anneal. Cross-sectional TEM revealed that severe Ti/Pt interdiffusion occurred, in one case leading to a Ti layer on the top surface.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 260: Symposium C – Advanced Metallization and Processing for Semiconductor Devices and Circuits , 1992 , 575
Copyright
Copyright © Materials Research Society 1992

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References

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