Atomic Layer Deposition of Oxide Thin Films with Metal Alkoxides as Oxygen Sources
Mikko Ritala,
1*
Kaupo Kukli,
1
Antti Rahtu,
1
Petri I. Räisänen,
1
Markku Leskelä,
1
Timo Sajavaara,
2
Juhani Keinonen
2
A chemical approach to atomic layer deposition (ALD) of
oxide thin films is reported here. Instead of using water or other compounds for an oxygen source, oxygen is obtained from a metal alkoxide, which serves as both an oxygen and a metal source when it
reacts with another metal compound such as a metal chloride or a metal
alkyl. These reactions generally enable deposition of oxides of many
metals. With this approach, an alumina film has been deposited on
silicon without creating an interfacial silicon oxide layer that
otherwise forms easily. This finding adds to the other benefits of the
ALD method, especially the atomic-level thickness control and excellent
uniformity, and takes a major step toward the scientifically
challenging and technologically important task of replacing silica as
the gate dielectric in the future generations of metal oxide
semiconductor field effect transistors.
1 Department of Chemistry, University of
Helsinki, Post Office Box 55, FIN-00014 University of Helsinki,
Finland.
2 Accelerator Laboratory, University of
Helsinki, Post Office Box 43, FIN-00014 University of Helsinki,
Finland.
*
To whom correspondence should be addressed. E-mail:
Mikko.Ritala{at}Helsinki.fi
Permanent address: Institute of Experimental Physics
and Technology, University of Tartu, Tähe 4, EE51010 Tartu,
Estonia.
