AVS 52nd International Symposium
    Thin Films Monday Sessions
       Session TF-MoP

Paper TF-MoP43
Characteristics of High-k Gate Dielectric Formed by Oxidation of Multi-layered Metal Films Deposited Directly on the Si Substrate by Sputtering

Monday, October 31, 2005, 5:00 pm, Room Exhibit Hall C&D

Session: Aspects of Thin Films Poster Session
Presenter: M.T. You, Sungkyunkwan University, Korea
Authors: M.T. You, Sungkyunkwan University, Korea
S.-W. Jeong, Sungkyunkwan University, Korea
H.J. Lee, Sungkyunkwan University, Korea
Y.-H. Roh, Sungkyunkwan University, Korea
Correspondent: Click to Email
Recently, we demonstrated that the oxidation of the Hf metal film deposited directly on the Si substrate by sputtering results in the HfSi@sub x@O@sub y@/HfO@sub 2@ stack layer with excellent electrical properties and high thermal stability in direct contact with Si. In this work, we further investigated the physical and electrical properties of high-k oxide films obtained by the oxidation and annealing of the multi-layered metal films (e.g., Hf/Zr/Hf, Zr/Hf/Zr, etc.) Thin metal films with the typical thickness of 1-2nm were deposited on the Si substrate alternately by rf-magnetron sputtering. Oxidation was performed at 500°C for 120min using the conventional furnace under O@sub 2@ ambient. Post oxidation annealing was done at several temperatures (i.e., 500, 700, and 900°C) for 90sec using a rapid thermal processor(RTP) under either N@sub 2@ or O@sub 2@ ambient. Data of HF C-V, I-V and Fowler-Nordheim tunneling (FNT) electron injection were analysed. TEM and XPS techniques were used to investigate the structural changes of the high-k films due to post oxidation annealing. The multi-layered high-k oxide films were formed after oxidizing the multi-layered metal films deposited directly on the Si substrate. The subsequent RTP annealing at high temperature (700°C) not only results in the poly-crystallization of the multi-layered high-k oxide films, but also causes the inter-diffusion of either Hf or Zr, resulting in the multi-layered high-k gate oxide. For example, HfSi@sub x@O@sub y@/HfO@sub 2@/intermixed-layer(IL)/ZrO@sub 2@/intermixed-layer(IL)/HfO@sub 2@, films were formed, if the Hf/Zr/Hf metal films were oxidized and subsequently annealed. The inter-diffusion of metal atoms improves electrical properties in general. In addition, the data obtained from the FNT electron injection either from the gate electrode or from the Si substrate indicate that the defect density changes depending on the annealing conditions.