Alumina based dielectric film for high energy storage density capacitor and preparation method

[0029] Example 1

[0030] Fabrication of 210nm-thick alumina-based thin films:

[0031] The steps for making an alumina-based thin film are as follows:

[0032] A 210nm hydrated alumina dielectric film was prepared on the surface of the Pt-plated silicon wafer by spin coating, and the following process steps were used:

[0033] First grind 0.02mol aluminum isopropoxide, then add 50ml ethylene glycol ether to ultrasonic for 10min, stir at 70°C for 30min; add 0.005mol bismuth nitrate pentahydrate, stir at 70°C for 30min; add 0.02mol ethyl orthosilicate, Stir at 70°C for 30 minutes; 0.02mol acetylacetone, continue stirring for 30 minutes; finally add 10ml of glacial acetic acid, stir at 90°C for 30 minutes, gradually cool to room temperature, and finally filter to obtain 60ml of sol precursor. Thermal analysis of the prepared colloids, data such as figure 1 shown. The crystallization temperature of the sample is 924°C, indicating high structural stability. The Pt-plated silicon wafer sample with clean and dry surface was placed on a glue spinner, and then the sol precursor was dropped on the surface of the substrate, and the sol was uniformly coated on the surface of the substrate at a speed of 3000 rpm, and then the sample was placed on the surface of the substrate. The rapid heat treatment furnace performs drying heat treatment. The process conditions of the pre-drying treatment are 150 ° C for 2 minutes, 350 ° C for 2 minutes, and 450 ° C for 2 minutes. After reaching 7 layers, the prepared amorphous alumina with the required thickness is placed in the Heat treatment in a muffle furnace for 3 hours, the required annealing equipment is a muffle furnace, the annealing system is a heating rate of 3 °C/min, and the temperature is kept at 450 °C for 3 hours.

[0034] The aluminum film with a diameter of 1 mm and a thickness of 120 nanometers was prepared on the surface of the aluminum oxide-based film sample by vacuum evaporation equipment, and the breakdown field strength and leakage conductance of the aluminum oxide-based film were studied.

[0035] figure 2 Shown is the atomic force microscopic surface topography of the sample. There are no obvious grains in the figure, and the fluctuation is small (between -1.3nm and 1.4nm), indicating that the prepared thin film is dense and uniform. (The surface of the film is dense and uniform, and it is not easy to see the difference. Here I replace it with the atomic force surface topography of the surface)

[0036] image 3 Shown is the I-V characteristic curve of the sample. In the figure, the leakage current increases gradually with the increase of voltage, and the current reaches about 1μA at about 60V. Thereafter the current did not change significantly with voltage until breakdown at 140V. The film prepared on the surface has high pressure resistance and low leakage conductance.

[0037] Example 2

[0038] Fabrication of 210nm-thick alumina-based thin films:

[0039] The steps for making an alumina-based thin film are as follows:

[0040] A 210nm hydrated alumina dielectric film was prepared on the surface of the Pt-coated silicon wafer by spin coating, as follows:

[0041] First grind 0.04mol of aluminum isopropoxide, then add 100ml of ethylene glycol ether to ultrasonic for 10min, stir at 70°C for 30min; add 0.01mol bismuth nitrate pentahydrate, stir at 70°C for 30min; add 0.04mol ethyl orthosilicate, Stir at 70°C for 30 minutes; 0.04mol acetylacetone, continue stirring for 30 minutes; finally add 20ml of glacial acetic acid, stir at 90°C for 30 minutes, gradually cool to room temperature, and finally filter to obtain 120ml of sol precursor.

[0042] A thin film was obtained by spun colloid heat treatment, and an aluminum film of 120 nm was plated on the surface of the obtained thin film for testing the breakdown field strength and leakage conductance. The above steps are the same as in Example 1.

[0043] Example 3

[0044] Fabrication of 270nm-thick alumina-based thin films:

[0045] The steps for making an alumina-based thin film are as follows:

[0046] A 270 nm hydrated alumina dielectric film was prepared on the surface of the Pt-coated silicon wafer by spin coating. details as follows:

[0047] 1) The preparation of alumina-based colloid is the same as in Example 2

[0048] 2) Preparation of alumina-based thin films:

[0049] The film preparation steps are as follows:

[0050]The Pt-plated silicon wafer sample with clean and dry surface was placed on a glue spinner, and then the sol precursor was dropped on the surface of the substrate, and the sol was uniformly coated on the surface of the substrate at a speed of 3000 rpm, and then the sample was placed on the surface of the substrate. The rapid heat treatment furnace performs drying heat treatment. The process conditions of the pre-drying treatment are 150 ° C for 2 minutes, 350 ° C for 2 minutes, and 450 ° C for 2 minutes. After reaching 9 layers, the prepared amorphous alumina with the required thickness is placed in the Heat treatment in a muffle furnace for 3 hours, the required annealing equipment is a muffle furnace, the annealing system is a heating rate of 3 °C/min, and the temperature is kept at 450 °C for 3 hours.

[0051] A thin film was obtained by spun colloid heat treatment, and an aluminum film of 120 nm was plated on the surface of the obtained thin film for testing the breakdown field strength and leakage conductance. The steps of spinning the film and making the gold film are the same as in Example 1.