Blackening method for lithium tantalite crystal substrate

A treatment method, lithium tantalate technology, applied in chemical instruments and methods, after treatment, crystal growth, etc., can solve the problems of difficult adjustment and control of mixed powder ratio, easy over-oxidation of active element, over-oxidation of Fe powder, etc. The chemical treatment method is simple and easy to implement, the resistivity control is easy, and the effect of strong deoxidation ability

Active Publication Date: 2016-04-06
上海召业申凯电子材料有限公司
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0012] Chinese patent CN200910017339 proposes the use of Li 2 CO 3 The powder mixed with Fe in a certain proportion is buried in LT or LN wafers and blackened in a nitrogen atmosphere to obtain LT substrates with high conductivity and no pyroelectricity. Although this technology has a simple process, it still uses high activity Fe powder, there are disadvantages such as difficult adjustment and control of mixed powder ratio, excessive oxidation of Fe powder, etc.
[0013] In summary, although the existing blackening reduction treatment technologies for lithium tantalate substrates can prepare LT blackened crystal substrates with high conductivity and no pyroelectricity, there are still complex processes, long process time, and excessive metal powder. The disadvantages of reducing lithium tantalate and active elemental substances are easy to over-oxidize and difficult to control the process.

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] A 4-inch LT crystal was prepared by the medium-frequency induction heating iridium crucible pulling method, and the growth atmosphere was 5% O by volume. 2 and 95% of N 2 In the mixed flow atmosphere, the grown LT crystals were pale yellow. High-temperature annealing is performed on the grown LT crystal to release the thermal stress, and then the LT crystal is polarized to obtain a monodomain crystal. LT crystals can prepare rough crystals with different crystal orientations according to needs (commonly used as Y36 degrees, Y42 degrees, Y38 degrees, X, etc.).

[0037] The above-mentioned 4-inch single-domain LT crystal is processed by orientation, cutting, and grinding to prepare a 4-inch LT crystal ingot, and then through multi-wire cutting and grinding to obtain a 4-inch LT crystal cut piece with a thickness of 0.2-0.5 mm. The substrate is colorless and transparent, and the resistivity of the unblackened 4-inch LT crystal substrate is as high as 3.4*10 13～ 1.4*10 ...

Embodiment 2

[0046] Embodiment 2: same as embodiment 1, except that the heat treatment temperature is 500 DEG C in the step 5) in the embodiment 1, and the processing time is 12 hours; all other steps and processes are the same.

[0047] The obtained 4-inch LT0.31mm thick Y36-degree LT substrate substrate is black, and its volume resistivity is 3.2*10 measured with a Keithley6517A special high-resistance meter. 11 Ωcm, the processed 4-inch LT crystal substrate can be used as the substrate of the SAW filter after grinding and polishing.

Embodiment 3

[0048] Embodiment 3: same as embodiment 1, except that the heat treatment temperature in the 5th) step is 595° C., and the heat treatment time is 10 hours, all other steps are the same. The obtained 4-inch LT0.31mm thick Y36-degree LT substrate substrate is black, and its volume resistivity is 4.9*10 measured by a Keithley6517A special high-resistance meter. 9 Ωcm, the processed 4-inch LT crystal substrate can be used as the substrate of the SAW filter after grinding and polishing.

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Abstract

The invention discloses a blackening method for a lithium tantalite crystal substrate. According to the method, a fluoride material and the to-be-treated lithium tantalite crystal substrate are contacted sufficiently, and the lithium tantalite crystal substrate is subjected to reductive heat treatment at the temperature of 450-600 DEG C in non-oxidative reducing atmosphere for 5-24 h. The volume resistivity of the lithium tantalite crystal substrate after blackening is 10<9>-10<12> omega cm. The method has the advantages that the method is simple, reliable and easy to operate, and the obtained lithium tantalite crystal substrate has good resistivity repeatability and low cost and is applicable to batch production.

Description

technical field [0001] The invention relates to a crystal material, in particular to a method for blackening a lithium tantalate crystal substrate. Background technique [0002] Lithium tantalate crystal (molecular formula LiTaO 3 , referred to as LT crystal), has an asymmetric central trigonal crystal structure (3m), crystal melting point of 1650 ° C, and Curie temperature of about 600 ° C, with excellent piezoelectric, ferroelectric, pyroelectric, acousto-optic, electro-optic, nonlinear As well as photorefractive properties, it has important application prospects in communication and optoelectronic fields such as surface acoustic wave (SAW) filters, pyroelectric detectors, optical modulators, and frequency conversion. As the substrate material of surface acoustic wave filter, LT crystal has outstanding advantages such as large electromechanical coupling coefficient, small frequency temperature coefficient and low insertion loss, and is widely used in high frequency (near ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C30B33/02C30B29/30
CPCC30B29/30C30B33/02
Inventor 赵广军万育仁杨胜裕姚诗凯
Owner 上海召业申凯电子材料有限公司
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