AVS 53rd International Symposium
    Thin Film Tuesday Sessions
       Session TF-TuP

Paper TF-TuP26
Ferroelectric Properties of Highly Oriented BLT Films using HfO@sub 2@ as Buffer Layers for Ferroelectric-Gate Field-Effect Transistors

Tuesday, November 14, 2006, 6:00 pm, Room 3rd Floor Lobby

Session: Thin Film Poster Session
Presenter: C.I. Lee, Ansan College of Technology, Korea
Authors: K.T. Kim, Chung-Ang University, Korea
G.H. Kim, Chung-Ang University, Korea
C.I. Lee, Ansan College of Technology, Korea
C.I. Kim, Chung-Ang University, Korea
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The bismuth layer-structured ferroelectrics (BLSFs) are attractive lead-free material for ferroelectric random access memory (FeRAM) application because of its relative fatigue free character.Metal-ferroelectric-semiconductor field-effect-transistors (MFSFETs) have advantages of high switching speed, nonvolatility, and high density. However, the MFSFETs have been problem such as interdiffusion between the film and Si. To suppress them, a metal-ferroelectric-insulator-semiconductor (MFIS) structure has been demonstrated. The most important thing in developing a MFIS structure is to find a good insulator that acts as a buffer between the Si substrate and the ferroelectric material, and have relative high dielectric constants, low leakage current, good interface characteristics, and compatibility. The buffer layers of HfO@sub 2@ were deposited as a buffer layer on Si and BLT thin films were used as a ferroelectric layer. The electrical and structural properties of the MFIS structure were investigated by varying the HfO@sub 2@ layer thickness. X-ray diffraction was used to determine the phase of the BLT thin films and the quality of the HfO@sub 2@ buffer layer. AES and TEM show no interdiffusion that suppressed by using the HfO@sub 2@ film as buffer layer. The width of the memory window in the C-V curves for the MFIS structure decreased with increasing thickness of the HfO@sub 2@ layer. The experimental results show that the BLT-based MFIS structure is suitable for non-volatile memory FETs with large memory window.