Investigation of TiO2-doped HfO2 thin films deposited by photo-CVD

THIN SOLID FILMS

卷:428

Article; Proceedings Paper

Fang, Q ; Zhang, JY ; Wang, ZM ; Wu, JX ; O'Sullivan, BJ ; Hurley, PK ; Leedham, TL ; Davies, H ; Audier, MA ; Jimenez, C ; Senateur, JP ; Boyd, IW

关键词: photo-CVD;    excimer lamp;    TiO2-doped HfO2 films;    high-k dielectrics;   

DOI  :  10.1016/S0040-6090(02)01221-X

来源: Elsevier

【 摘 要 】

TiO2-doped HfO2 thin films, as potential replacements for SiO2 as high-k gate dielectric material, have been grown by photo induced CVD using 222 nm excimer lamps at a temperature of 400 C. Vaporised titanium isopropoxide and hafnium (IV) tetrat-butoxide were used as the precursors. Films from approximately 45-70 nm in thickness with refractive indices from 1.850 to 2.424 were grown with various Ti:Hf ratios. The as-deposited films were found to be amorphous by X-ray diffraction when the Ti/(Ti+Hf) value was up to 33%, while the crystalline TiO2 anatase phase formed when the Ti/(Ti+Hf) was 41%. We also found that the refractive index increased sharply when the Ti/(Ti+Hf) was over 25%. Fourier transform infrared spectroscopy, XPS and TEM were also used to monitor as well as the presence of Ti, interface and microstructure of the films on Si-substrate. The effect of UV annealing on the electrical properties of these films will also be discussed. (C) 2002 Elsevier Science B.V. All rights reserved.

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