Chemical etching method for bismuth selenide material

Abstract

The invention relates to a chemical etching method for a bismuth selenide material. The chemical etching method includes the following steps that 1, a mask is manufactured, wherein the mask is a photolithographic mask and is manufactured through standard lithography and attached to the bismuth selenide material on a silicon substrate; 2, an etching agent is prepared, wherein the etching agent is a compound potassium bichromate acid solution and is prepared by evenly mixing, by volume percent, 9% of a potassium dichromate saturated aqueous solution, 48% of concentrated hydrochloric acid and 98% of concentrated sulfuric acid in a certain proportion; 3, etching is conducted, wherein compound potassium bichromate acid solution etching liquid obtained in step 2 is utilized to conduct etching on the bismuth selenide material of the attachement photolithographic mask obtained in attachment step 1. The chemical etching method is simple in process, convenient and fast to operate, low in cost and remarkable in effect and has the advantages that the etched bismuth selenide material is smooth in surface and meets the stoichiometric ratio, and the etching rate is convenient to control.

Description

technical field [0001] The invention relates to a chemical etching method for bismuth selenide material. Background technique [0002] Bismuth selenide (Bi 2 Se 3 ) is a traditional thermoelectric material. In recent years, studies have found that it is a strong topological insulator quantum material, and its bulk energy band gap is wide (~0.3eV). It is one of the topological insulator materials that are most likely to be applied at room temperature. Etching is a very necessary step in the process of making bismuth selenide into various thermoelectric energy devices and micro quantum devices. At present, the etching technology is mainly divided into dry etching and wet etching. The plasma equipment required for dry etching is expensive, the operation is complicated, and there is no selectivity to the etching of materials, so the damage to the mask is relatively large. Large; wet etching is divided into electrochemical etching and chemical etching, etc. Among them, chemica...

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Problems solved by technology

[0003] However, there are certain technical limitations when using existing etchant to etch BiSe Bismuth oxide is used to etch the surface to reveal the morphology of defect etch pits; the second type - aqua regia etchant has the problems of too fast etching rate and uneven etching, and it is difficult to obtain a flat etching interface. Especially when etching bismuth selenide thin film materials, the etching rate at the film and substrate interface is too fast and easily causes the film layer to fall off; the (3) class——etching agent can obtain a smooth etching interface and can However, our recent research has found that with the different types of acid solutions in the potassium dichromate etchant, the etching rates of selenium and bismuth components are quite different, so it is easy to cause selenization as the etching progresses. Surface deviation of bismuth material from stoichiometric ratio

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