A kind of chemical etching method of bismuth selenide material

Abstract

The present invention relates to a chemical etching method for bismuth selenide material, which comprises the following steps: (1) making a mask: the mask is a photolithography mask, which is made by standard photolithography technology and attached to a silicon substrate (2) preparation of etchant: the etchant is a potassium dichromate complex acid solution, and its preparation method is that the following components are mixed according to a certain proportion, and the volume percentage Be 9% potassium dichromate saturated aqueous solution, the concentrated hydrochloric acid that volume percentage is 48%, the concentrated sulfuric acid that volume percentage is 98%; (3) etching: utilize the potassium dichromate compound acid solution that step (3) makes The etchant is used to etch the bismuth selenide material attached to the photolithography mask prepared in the attaching step (1). The invention has the advantages of simple process, convenient operation, low cost and remarkable effect. The surface of the etched bismuth selenide material is smooth, conforms to the stoichiometric ratio, and the etching rate is easy 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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