Mono-crystal strontium titanate substrate with atomic-scale step structure and preparation method of substrate

Abstract

The invention discloses a preparation method of a mono-crystal strontium titanate substrate with an atomic-scale step structure. The preparation method includes the steps: performing first ultrasonic cleaning on an untreated strontium titanate substrate; corroding the strontium titanate substrate cleaned for the first time by ammonium fluoride-hydrofluoric acid buffer solution; annealing the obtained strontium titanate substrate in high-temperature flowing oxygen atmosphere; performing second ultrasonic cleaning on the annealed strontium titanate substrate to obtain the mono-crystal strontium titanate substrate with the atomic-scale step structure; discharging the obtained mono-crystal strontium titanate substrate with the atomic-scale step structure. According to the preparation method, the mono-crystal strontium titanate substrate can be directionally corroded to form a titanium-oxygen ending surface with the step structure, power of hydrogen is proper, the surface is in an obvious step shape, surface root-mean-square roughness is low, and the whole step surface is free from corrosion holes.

Description

technical field [0001] The invention relates to the technical field of substrate materials, in particular to a single-crystal strontium titanate substrate substrate with an atomic-level step structure and a preparation method thereof. Background technique [0002] Strontium titanate (SrTiO 3 ) substrate is one of the most widely used excellent high temperature superconducting single crystal substrates. In the application of many high-temperature functional materials such as superconducting materials (such as yttrium barium copper oxide), ferroelectric or multiferroic thin film materials (such as bismuth ferrite), strontium titanate single crystal substrate has a good degree of lattice matching, no twins Crystal structure, and excellent physical and mechanical properties, therefore, strontium titanate single crystal substrate has extremely important application value in scientific and production activities. The properties and surface shape of the strontium titanate substrat...

AI Technical Summary

Problems solved by technology

[0004] Ammonium fluoride buffer chemical method is widely used, but the acid value and ion species configuration of the buffer in this method are rarely involved, so the optimal buffer corrosion solution conditions and chemical reaction time have not been explored, so that the preparation The strontium titanate substrate surface often has a coral-like step surface, and the defects and holes are obvious. High-quality functional films will have grain boundaries or non-ideal polycrystalline states at the defects, and the holes are easy to appear. The island-like growth mode of the film, not the layered growth mode, there will be screw dislocations in the island-like growth mode, which are all high-quality functional films to avoid

[0005] Another treatment method is the physical method of high-temperature annealing. This method is difficult to reconstruct the surface by simply relying on temperature control of the surface atoms of the substrate to overcome its own kinetic barrier. Steps, and white needle-like unknown objects are often precipitated on the surface, which is not conducive to the growth of high-quality functional films

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