Composite ferroelectric film and low-temperature preparation method thereof

A ferroelectric thin-film, low-temperature technology, used in circuits, electrical components, semiconductor/solid-state device manufacturing, etc., can solve problems such as difficulty in meeting the requirements of micro-devices, high crystal growth temperature, affecting film performance, etc., to reduce leakage current, The effect of low preparation temperature and improved fatigue resistance

CN101054671AInactive Publication Date: 2007-10-17TONGJI UNIV
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2007-10-17
Estimated Expiration
Not applicable · inactive patent

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Abstract

The present invention belongs to the field for preparing composite ferro-electricity thin films by adopting sol-gel method.Said low temperature preparation method for composite thin films in accordance with the present invention is as follows: above all, preparing a precursor solution using sol-gal process and spin-coating a thin film with desirable thickness on the substrate Pt / Ti / SiO2 / Si and Ti at heat treating temperature of 300-400 DEG C for each thin film, then impregnating the thin film into a hydrothermal solution of 90-300 DEG C for 10-30 h, putting the thin film at a pure oxygen entironment of 1-35 MPa for a treatment for 10-30 hours, sputtering aurum on its surface for acting as an upper electrode. Said process in accordance with the present invention has a low preparing temperature and resolves the compatible technical problems of ferro-electricity film membrane and semi-conductor integrated circuit process. In addition, during thin film crystal grain growth at hydrothermal and high pressure oxygen conditions, the defect is reduced and then ferro-electricity thin film with high performances is obtained.
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Description

technical field

[0001] The invention belongs to the technical field of low-temperature preparation of composite ferroelectric thin films by sol-gel method. Background technique

[0002] In the past few decades, a variety of thin film preparation methods have been adopted to prepare ferroelectric thin films, including: different physical vapor deposition techniques plasma sputtering deposition (PSD) and ion beam sputtering deposition (IBSD ), pulsed laser flash deposition (PLAD), molecular beam evaporation epitaxy (MBE) in electron beam or electric furnace, metal organic vapor deposition (MOCVD), chemical dissolution (MOD such as: sol-gel process and metal organic deposition method ). Generally speaking, in the process of preparing thin films by these methods, the temperature of crystal growth is relatively high (≥550°C), which will cause interdiffusion at the interface of film / electrode / substrate, which will affect the performance of the film and is difficult to meet micro...

Examples

Embodiment 1

[0017] Embodiment 1: prepare BaTiO 3 Ferroelectric thin film

[0018] The chemical raw material used is barium acetate [Ba(CH 3 COO) 2 ] and titanium isopropoxide [Ti(OC 3 h 7 ) 1 ], the solvent is glacial acetic acid and ethylene glycol ether. First heat barium acetate (according to a certain stoichiometric ratio) in glacial acetic acid solution to boiling, stop heating after 5 minutes, and cool to room temperature, the molar ratio of Ba to glacial acetic acid is 1:10. Then add the mixed solution of titanium isopropoxide, ethylene glycol ethyl ether and acetylacetone (AcAc) into the barium-containing glacial acetic acid solution, wherein: the molar ratio of Ti to AcAc is 1:2, titanium isopropoxide: ethylene diacetone The molar ratio of alcohol to ether is 1:10. Finally, ethylene glycol ether was added to adjust the concentration of the final solution to 0.3M. After standing for 24 hours, it was used to prepare the film.

[0019] The substrate used is Pt / Ti / SiO 2 / Si...

Embodiment 2

[0021] Embodiment 2: preparation (Ba x Sr 1-x )TiO 3 , (x=0-0.9) ferroelectric thin film

[0022] The chemical raw material used is barium acetate [Ba(CH 3 COO) 2 ], strontium acetate [Sr(CH 3 COO) 4 ] and titanium isopropoxide [Ti(OC 3 h 7 ) 4 ], the solvent is glacial acetic acid and ethylene glycol ether. First heat barium acetate and strontium acetate (according to a certain stoichiometric ratio x=0.10) in glacial acetic acid solution to boiling, stop heating after 10 minutes, and cool to room temperature, the molar ratio of Ba+Sr to glacial acetic acid is 1: 10. Then the mixed solution of titanium isopropoxide, ethylene glycol ethyl ether and acetylacetone (AcAc) is added to the glacial acetic acid solution containing barium and strontium, wherein: the molar ratio of Ti to AcAc is 1: 2, titanium isopropoxide and The molar ratio of ethylene glycol ether is 1:10. Finally, ethylene glycol ether was added to adjust the concentration of the final solution to 0.3M. ...

Embodiment 3

[0025] Embodiment 3: preparation (Ba x Sr1-x )TiO 3 , (x=0-0.9) ferroelectric thin film

[0026] The film prepared by the sol-gel method is the same as in Example 2, the temperature of the hydrothermal treatment is changed to 300°C, and the immersion time is 12 hours. The film after hydrothermal treatment was placed in an autoclave at 100°C, the pressure of pure oxygen was 8 MPa, and it was taken out after heat treatment for 20 hours. Finally, a gold electrode was sputtered on the upper surface by DC sputtering method as the upper electrode, and its diameter was 0.5 mm, the thickness is about 100nm.