Preparation of strontium-barium titanate film material

A strontium barium titanate thin film and substrate technology, which is applied in metal material coating process, gaseous chemical plating, coating, etc., can solve the problems of slow growth rate, deviation of film composition, and large distance of process compatibility, etc. , to achieve excellent ferroelectric properties, uniform particle size, and eliminate the effect of crystal nucleus formation and diffusion process

Active Publication Date: 2008-10-29
上海太阳能电池研究与发展中心
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Problems solved by technology

Chinese patent: CN1932080A "A Preparation Method of Barium Strontium Titanate Thin Film Material", this patent introduces the magnetron sputtering preparation method of barium strontium titanate thin film material. The film prepared by this method has the disadvantage of growing The speed is slow, and there is a certain deviation between the film composition and the target material
However, due to the complex structure and elemental composition of BST ferroelectric thin films, the quality and process compatibility of BST ferroelectric thin films grown by MOCVD systems still have a long way to go with practical requirements. The deposition process of BST ferroelectric thin films , microstructure, dielectric properties and other aspects need to be further studied

Method used

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  • Preparation of strontium-barium titanate film material

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Comparison scheme
Effect test

Embodiment 1

[0025] The cleaned (001)SrTiO 3 The substrate is placed in the reaction chamber, and argon gas is introduced to keep the pressure in the reaction chamber at 1 Torr, and the cooling water of the system is connected, and the water temperature is kept at 25°C. The temperature of the substrate was raised to 1000° C. and maintained for 1 minute, and the substrate was cleaned. Then the temperature of the substrate was lowered to 900° C., kept for 2 minutes and oxygen was introduced at the same time, the flow rate was 120 sccm, the pressure was stabilized at 2 Torr, and the substrate was oxidized under a mixed atmosphere of argon and oxygen.

[0026] One-stage growth of BST film: In situ, the oxidized substrate is lowered to 650°C for 50 minutes, and the precursor Ba(dfhd) is introduced at the same time 2 (tetraglyme), Sr (dfhd) 2 (tetraglyme) and TTIP-Ti(OC3H7) 4 , respectively as sources of Ba, Sr and Ti; the flow rates were 60 sccm, 60 sccm, and 20 sccm; the temperatures of the...

Embodiment 2

[0028] The rest of the growth conditions are the same as in Example 1, except that the growth of the film is a two-stage growth, that is, the nucleation stage is 650°C, and after holding for 20 minutes, the temperature is rapidly raised at a rate of 200°C / s, and the temperature is raised to 800°C. 30 minutes for film growth. Then the oxygen was turned off, and the BST film sample in the reaction chamber was lowered to room temperature in an argon atmosphere. Finally, the BST film samples were heat-treated according to the above method §6.

[0029] See figure 1 , it can be seen from the figure that the diffraction peak intensity (curve 1) of the BST film grown in one stage at 650°C is weaker than that of the BST film grown in two stages (curve 2), indicating that BST is in the growth stage at 650°C. The nuclear stage is in the growth stage at 800°C.

Embodiment 3

[0031] The cleaned (001)SrTiO3 The substrate is placed in the reaction chamber, and argon gas is introduced to keep the pressure in the reaction chamber at 3 Torr, and the cooling water of the system is connected to keep the water temperature at 25°C. The temperature of the substrate was raised to 1000° C. and maintained for 3 minutes, and the substrate was cleaned. Then the temperature of the substrate was lowered to 900° C., kept for 2 minutes and oxygen gas was introduced at the same time, the flow rate was 150 sccm, the pressure was stabilized at 4 Torr, and the substrate was oxidized under a mixed atmosphere of argon and oxygen.

[0032] Then lower the temperature to 650°C and keep it for 20 minutes while feeding the precursor Ba(dfhd) 2 (tetraglyme), Sr (dfhd) 2 (tetraglyme) and TTIP-Ti(OC3H7) 4 , respectively as sources of Ba, Sr and Ti; the flow rates were 60 sccm, 60 sccm, and 20 sccm; the temperatures of the sources were 125°C, 125°C, and 70°C, respectively. The t...

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Abstract

The invention provides a method for preparing barium strontium titanate thin film material. The method adopts Ba(dfhd)2(tetraglyme), Sr(dfhd)2(tetraglyme) and TTIP-Ti(OC3H7)4 as the precursors; oxygen is taken as the reacting gas; argon is taken as the carrier gas; barium strontium titanate (BST) thin film is rapidly deposited by adopting a two-stage growth method, namely the arium strontium titanate (BST) thin film is in nucleation stage at the temperature of 650 to 700 DEG C, and is in growth stage at the temperature of 800 to 850 DEG C; then heat treatment is performed in an oxygen atmosphere at the temperature of 400 to 600 DEG C. Because quick temperature rise is adopted from the nucleation stage to the growth stage, non ideal nucleation and diffusion process can be eliminated. BST thin film with high orientation and even granule size is obtained by adopting the method. The thin film is an ideal material used for the dynamic random access memory, the monolithic microwave integrated circuit, the dielectric phase shifter and the uncooled infrared focal plane array.

Description

technical field [0001] The invention relates to a growth method of a ferroelectric thin film material, in particular to a method for preparing a barium strontium titanate thin film material based on a chemical vapor deposition method. Background technique [0002] Ferroelectric thin film materials refer to thin film materials with ferroelectric properties and a thickness ranging from tens of nanometers to several microns. It has a series of excellent properties such as ferroelectricity, piezoelectricity, pyroelectricity, electricity, and optics. Ferroelectric thin film materials are mainly used in three fields: microwave devices (such as filters, phase shifters), memories (such as ferroelectric RAM), and microsystems (such as microsensor arrays). Partial substitution of Sr atoms for BaTiO 3 Ba atom in, we can get barium strontium titanate (Ba, Sr)TiO 3 (referred to as BST). BST ferroelectric film has the characteristics of large dielectric coefficient, strong nonlinearity...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C23C16/18C23C16/455C23C16/30C23C16/52C23C16/56
Inventor 褚君浩江锦春石富文
Owner 上海太阳能电池研究与发展中心
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