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Making method of lithium tantalate black wafer

A production method, lithium tantalate technology, applied in chemical instruments and methods, single crystal growth, polycrystalline material growth, etc., can solve the problem of low pyroelectricity, unstable chemical properties of chloride and fluoride, and difficult control of blackening degree and other problems, to achieve the effect of simple and easy production method, easy control of reduction degree, and elimination of pyroelectric effect

Inactive Publication Date: 2017-03-29
CHINA ELECTRONICS TECH GRP NO 26 RES INST
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Although the method of above-mentioned reduction treatment is easy to obtain the lithium tantalate black sheet of low resistivity and low pyroelectricity, above-mentioned chloride, hydride, fluoride are chemically unstable, and poisonous, safety is not high, and its waste material is harmful to environment. harm
[0010] Chinese patent CN201610660753.4 proposes to use a kind of glue mixed with lithium carbonate and Zn powder to uniformly coat both sides of the lithium tantalate substrate to be processed by screen printing, and to apply it under flowing nitrogen at a temperature of 400-600°C. Blackening treatment, similarly, due to the strong oxidation ability of Zn powder, the degree of blackening is not easy to control
Moreover, the melting point of zinc is about 420°C, and processing at its melting point temperature will easily cause problems such as uneven blackening
At the same time, the method of coating is adopted, which is cumbersome to operate and low in efficiency
[0011] In summary, although the lithium tantalate black flakes produced by the existing reduction treatment have the characteristics of low resistivity, low transmittance, and low pyroelectricity, they have complex processes, low efficiency, excessive oxidation, unsafety, and incomplete blackening. Disadvantages such as uniformity

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0043] Example 1: Mix carbon powder and lithium carbonate powder evenly at a mass ratio of 0.1:1 to make an investment. Then put the lithium tantalate wafer to be processed into the crucible container one by one, add the embedding material, completely embed the wafer in it, and then put it into the heat treatment furnace. Vacuum down to below 50Pa, then heat up to 450°C at a rate of 120°C / h for reduction treatment for 15 hours. After the heat preservation is over, the temperature is lowered to room temperature at a rate of 120°C / h, and the lithium tantalate wafers are taken out one by one, and the black wafers are completed. The resistivity of the prepared lithium tantalate black sheet is about 5×10 11 Ω.cm or so.

Embodiment 2

[0044] Example 2: Mix carbon powder and lithium carbonate powder evenly at a mass ratio of 0.2:1 to make an investment. Then put the lithium tantalate wafer to be processed into the crucible container one by one, add the embedding material, completely embed the wafer in it, and then put it into the heat treatment furnace. Vacuum down to below 50Pa, then heat up to 500°C at a rate of 100°C / h for reduction treatment for 20 hours. After the heat preservation is over, the temperature is lowered to room temperature at a rate of 100°C / h, and the lithium tantalate wafers are taken out one by one, and the black wafers are completed. The resistivity of the prepared lithium tantalate black sheet is about 6×10 10 Ω.cm or so.

Embodiment 3

[0045] Example 3: Mix carbon powder and lithium carbonate powder evenly at a mass ratio of 0.3:1 to make an investment. Then put the lithium tantalate wafer to be processed into the crucible container one by one, add the embedding material, completely embed the wafer in it, and then put it into the heat treatment furnace. Vacuum down to below 50Pa, then heat up to 550°C at a rate of 50°C / h for reduction treatment for 25 hours. After the heat preservation is over, the temperature is lowered to room temperature at a rate of 50°C / h, and the lithium tantalate wafers are taken out one by one, and the black wafers are completed. The resistivity of the prepared lithium tantalate black sheet is about 2×10 10 Ω.cm or so.

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Abstract

The invention discloses a making method of a lithium tantalate black wafer. The method comprises the following steps: 1, weighing IV group nonmetal element powder and carbonate powder according to a certain ratio, and uniformly mixing the weighed powders to obtain an embedding material; 2, placing a lithium tantalate wafer to be processed in a crucible container, adding the embedding material to completely embed the wafer, and placing the crucible in a heat treatment furnace; 3, heating the lithium tantalate wafer to a heat insulation temperature in vacuum or inert or reducing flow atmosphere; 4, keeping the heat insulation temperature unchanged for 10-40 h; and 5, cooling the obtained wafer to room temperature after the heat insulation ends, and taking out the lithium tantalate wafer to obtain the black wafer. The method greatly reduces the electric resistivity of the wafer without influencing the piezoelectric performances or the single domain property of lithium tantalite, weakens and even eliminates the self pyroelectric effect of the wafer, enhances the absorption ability in the visible light region, and improves the lithography precision in the device making process.

Description

technical field [0001] The invention relates to a crystal material, in particular to a method for manufacturing a lithium tantalate black sheet, and belongs to the field of crystal post-processing. Background technique [0002] With the rapid development of the current wireless Internet, the rapid popularization of 4G networks and smart phones, the demand for surface acoustic wave (SAW) filters has increased significantly, and the requirements for frequency and bandwidth have also become higher and higher, and a large number of them require high frequency and large bandwidth. SAW filters, among which high-performance RF SAW filters are key components that are urgently needed by the market, and the market space is broad. In the future, with the continuous evolution of 4G to 5G networks and the application of new technologies such as carrier aggregation (CA), multiple transmission and multiple reception (MIMO), and micro base stations (Small Cell), the number of filters requir...

Claims

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Application Information

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IPC IPC(8): C30B29/30C30B33/02
CPCC30B29/30C30B33/02
Inventor 龙勇石自彬于明晓李和新
Owner CHINA ELECTRONICS TECH GRP NO 26 RES INST
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