Berlin 2008 – wissenschaftliches Programm

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DS: Fachverband Dünne Schichten

DS 22: High-k Dielectric Materials - Synthesis, Properties, Applications

DS 22.1: Hauptvortrag

Mittwoch, 27. Februar 2008, 16:45–17:15, H 2032

Development of novel processes for atomic layer deposition of high-k dielectrics — •Jaakko Niinistö, Kaupo Kukli, Mikko Ritala, and Markku Leskelä — Laboratory of Inorganic Chemistry, Department of Chemistry, P.O. Box 55, FI-00014 University of Helsinki, Finland

Atomic layer deposition (ALD) has gained considerable interest in the recent years as a thin film deposition method to overcome many technological problems faced by the semiconductor industry. Deposition of high-k materials for CMOS and DRAM applications are the main application areas for ALD.

The success of ALD is built on chemistry. The unique characteristics of ALD can be achieved and benefited only with precursors that provide the self-limiting film growth through the saturative surface reactions. For high-k materials the leading solutions include the oxides of Hf and Zr. For ALD of these materials, alkylamides have gained wide interest as precursors. However, thermal decomposition of the alkylamides at rather low temperatures prevent the ALD-type growth mode. The need for process development and existing ALD processes of ZrO2 and HfO2 with recent advancements are discussed.

In this presentation, recent research with cyclopentadienyl-precursors, which offer high thermal stability, is reviewed. In addition, we introduce mixed alkylamido-cyclopentadienyl precursors of Zr and Hf. With ozone as the oxygen source, the process yields ZrO2 films with high permittivity cubic phase and low leakage current density. Finally, results of doping the ZrO2 and HfO2 films are presented.