TY - JOUR
T1 - Lateral grain size enlargement and surface flattening of Cu thin films by using adequate underlayers and by thermal annealing in ultra high vacuum
AU - Imakita, Kenichi
AU - Tsunoda, Masakiyo
AU - Takahashi, Migaku
PY - 2004
Y1 - 2004
N2 - The effects of body centered cubic (BCC) solid solution underlayers on the metallurgical size and flatness of Cu thin films, fabricated on them, were investigated. As the underlayer materials, Cr80Al20, Cr90Ni10, Cr80Fe20, Fe 75Cr25 and Fe were examined. Lateral grain size of the Cu films fabricated on the Cr-Al, Cr-Ni, Cr-Fe, Fe-Cr under layer was enlarged, comparing to that on the Fe underlayer. The difference between the surface energy (γSX) and the interfacial energy (γSLX-Cu) of these underlayer is close to the surface energy of Cu at the melting point (γS Cu(Tm)). However, the surface roughness of Cu films simultaneously increased with increasing the lateral grain size. In order to suppress the surface roughening of Cu films, post-thermal annealing procedure was applied under the ultra-high vacuum for the films fabricated on the Cr-Ni and Cr-Ni-Fe underlayers. We finally succeeded to enlarge the lateral grain diameter more than 100 nm for 50-nm-thick Cu films, maintaining a fiat surface (Ra = 0.32 nm).
AB - The effects of body centered cubic (BCC) solid solution underlayers on the metallurgical size and flatness of Cu thin films, fabricated on them, were investigated. As the underlayer materials, Cr80Al20, Cr90Ni10, Cr80Fe20, Fe 75Cr25 and Fe were examined. Lateral grain size of the Cu films fabricated on the Cr-Al, Cr-Ni, Cr-Fe, Fe-Cr under layer was enlarged, comparing to that on the Fe underlayer. The difference between the surface energy (γSX) and the interfacial energy (γSLX-Cu) of these underlayer is close to the surface energy of Cu at the melting point (γS Cu(Tm)). However, the surface roughness of Cu films simultaneously increased with increasing the lateral grain size. In order to suppress the surface roughening of Cu films, post-thermal annealing procedure was applied under the ultra-high vacuum for the films fabricated on the Cr-Ni and Cr-Ni-Fe underlayers. We finally succeeded to enlarge the lateral grain diameter more than 100 nm for 50-nm-thick Cu films, maintaining a fiat surface (Ra = 0.32 nm).
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U2 - 10.3131/jvsj.47.124
DO - 10.3131/jvsj.47.124
M3 - Article
AN - SCOPUS:33750805728
VL - 47
SP - 124
EP - 127
JO - Shinku/Journal of the Vacuum Society of Japan
JF - Shinku/Journal of the Vacuum Society of Japan
SN - 0559-8516
IS - 3
ER -