SU1682417A1 - Etching solution for iron-yttrium garnet epitaxial films - Google Patents

Abstract

The invention relates to chemical compounds and is intended for precision etching of epitaxial films based on iron yttrium garnet. Elements of the required configuration made by etching from these films are used in radio engineering devices, such as gyromagnetic filters, delay lines, etc. The aim of the invention is to increase the etching rate while ensuring the high quality of the borders of selectively etched elements. To achieve the goal, a trailer containing concentrated nitric acid and phosphoric acid in a ratio of 5 and 95 wt.%, Respectively, is used. Etching is carried out at a temperature of about 175 ° C. At this temperature, nitric acid decomposes with the release of nitrogen dioxide, which causes an increase in the etching rate of epitaxial films with a thickness of 20 µm to 3-4 µm / min. When this concentration of nitric acid is exceeded, the etching rate increases even more, but at the same time the quality of the boundaries of the etched elements begins to deteriorate.

Description

The invention relates to chemical compounds and is intended for precision etching of epitaxial films based on iron yttrium garnet (YIG), obtained by liquid-phase epitaxy on monocrystalline gallium-halogen garnet substrates, produced by etching from these films, elements of the required configuration are used in radio engineering devices of radio engineering garnet, elements of the required configuration are obtained by etching from these films, elements of the required configuration are used in radio engineering devices of radio engineering garnet, and elements of the required configuration are etched from these films using the necessary configuration elements used in radio engineering devices using radio engineering technology. gyromagnetic filters, delay lines, etc.

The aim of the invention is to increase the etching rate while ensuring the high quality of the borders of selectively etched elements.

This goal is achieved by the fact that the etchant for YIG epitaxial films, containing orthophosphoric acid, additionally contains concentrated nitric acid in the following ratio of components, May. %: Nitric acid (concentrated) 5 Orthophosphoric

Acid Remaining

Etching is performed at a temperature of about 175 ° C, close to the boiling point of phosphoric acid. At this temperature, the nitric acid introduced into the herbal composition decomposes to release nitrogen dioxide. Nitrogen dioxide is a strong oxidizing agent, which causes

an increase in the rate of etching of epitaxial YIG films.

Experimental studies have shown that the introduction of nitric acid increases the etching rate. YIG films 20 µm thick are completely etched (with the exception of areas covered with a protective layer) in 5-7 minutes. The etching rate is at least 3-4 µm / min, i.e. more than 3 times the rate of etching in the famous etchant from orthophosphoric acid (without additives).

With the addition of nitric acid in an incomplete amount than the 5% indicated, the etching rate decreases. If the indicated value is exceeded, the etching rate

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five

increases even more, but at the same time the quality of the borders of the etched elements begins to deteriorate.

Claims (1)

Claims Etchant for epitaxial films based on iron yttrium garnet containing orthophosphoric acid, characterized in that, in order to increase the etching rate while ensuring the high quality of the boundaries of selectively etched elements, the etchant additionally contains concentrated nitric acid in the following ratio of components, wt.%: Concentrated nitric acid5 Orthophosphoric acid Else