Production method of 8-inch lithium niobate crystal

Abstract

The invention relates to the technical field of optoelectronic materials, and discloses a production method of an 8-inch lithium niobate crystal, wherein the production method comprises the followingsteps: (1) preparation of a polycrystalline raw material: mixing and sintering lithium carbonate and niobium oxide raw materials, briquetting and crushing to obtain a polycrystalline raw material; (2)crystal growth: putting the polycrystalline raw material into a platinum crucible located in a multilayer temperature field, carrying out crystal growth by adopting a pulling method, and carrying outcrystal initiation, necking, shoulder extending, shoulder contracting, equal-diameter growth and pulling-out to obtain a multi-domain crystal; and (3) crystal annealing and polarizing: embedding themulti-domain crystal into the polycrystalline raw material, and annealing and polarizing to obtain the 8-inch lithium niobate crystal. In the crystal growth process, multiple layers of temperature fields are adopted, it is guaranteed that the temperature fields are uniform and free of mutation, crystal polycrystal and cracking are avoided, and crystal growth is easier to control; a powder buryingmethod is adopted for annealing polarization, so that crystals are not easy to crack; during preparation of the polycrystalline raw material, multiple times of mixing and sintering are performed, andstable Curie temperature of crystals can be ensured.

Description

technical field [0001] The invention relates to the technical field of optoelectronic materials, in particular to a production method of an 8-inch lithium niobate crystal. Background technique [0002] Lithium niobate single crystal is an excellent multifunctional artificial crystal, which is known as the ferroelectric with the highest Curie temperature and the largest spontaneous polarization, and exhibits a combination of electrical, optical, nonlinear and other properties. It is a rare and widely used artificial crystal with good piezoelectric properties, nonlinear optical properties, electro-optic and photorefractive properties, etc. It can be used to make various functional devices, such as: surface acoustic wave devices, Infrared detectors, laser modulators, optical switches, optical parametric oscillators, integrated optical components, high-frequency broadband filters, high-frequency high-temperature transducers, microacoustic devices, laser frequency doublers, self-...

AI Technical Summary

Problems solved by technology

[0006] The present invention is to overcome when using the method in the prior art to produce 8-inch lithium niobate crystals, because the crystal diameter becomes larger, the amount of crystallization in the crystal growth process is too large, the melt weight changes too fast, and the temperature of the whole crystal growth is also caused. If the gradient changes too fast, it is easy to cause polycrystalline and cracking of the crystal; at the same time, due to the increase of the crystal diameter, the temperature difference between each part of the crystal is also increased, which increases the difficulty of annealing and polarization, and is prone to uneven polarization. Phenomenon, if the current is too large, cracking may occur. A production method for 8-inch lithium niobate crystals is provided. By setting a multi-layer temperature field in the growth device, it is ensured that the temperature field is uniform and there is no sudden change during the entire crystal growth process. And the buried powder method is used for annealing and polarization, which can effectively avoid crystal cracking and obtain a fully polarized eight-inch large-scale qualified lithium niobate single crystal

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