CS258709B1 - Method of visualizing crystallographic disorders in phosphite indite InP orientation (001) - Google Patents

Abstract

The solution concerns a method of visualizing crystallographic defects in indium phosphide of InP orientation (001) by the photoetching method. The essence of the solution is that indium phosphide is treated with a mixture of potassium hydroxide and potassium hexacyanoferrate in the form of an aqueous solution at a temperature of 15 to 50 °C for 1 and 20 min. under intensive stirring and illumination, while the solution contains 6.5 to 10 wt. % potassium hydroxide and 3 to 7 wt. % potassium hexacyanoferrate. The solution can be used to determine the suitability of indium phosphide for the production of microwave and optoelectronic elements.

Description

The invention relates to a method for visualizing crystallographic disturbances in phosphide by indite InP orientation (001), by means of photo-etching with a mixture composed of aqueous solutions of potassium hydroxide and potassium ferricyanide.

Indium phosphide compound InP with semiconductor properties is suitable for the preparation of microwave and optoelectronic elements. Crystallographic disturbances in the material cause degradation of these elements. One method to identify and visualize these disorders is photo-etching, ie chemical etching when irradiating the material with an external light source. So far, two types of etch have been used to photo-etch indium phosphide InP, which make visible crystallographic disturbances, in particular dislocations and growth lines. The etching composed of phosphoric acid 1 H 3 PO 4 and hydrogen peroxide H ₂ O _2, due to the etching rate, makes visible defects only on the surface of the material or defects on the surface of the oyster, such as dislocation.

An etch composed of chromium trioxide CrO ₃ , hydrofluoric acid 1 HF and water H ₂ O makes not only surface defects visible but also defects inside the material, thereby determining the geometric shape and arrangement of the defects in the material. As this etching agent contains hydrofluoric acid, working with it is dangerous and harmful to health. The second disadvantage is that the used containers, tools, appliances cannot be made of glass, because this acid and its vapors etch the glass.

The above-mentioned deficiencies are eliminated by the method of visualization of crystallographic disturbances in phosphide by indite InP orientation (001) by the photo-etching method, which is based on treating indium phosphide InP orientation (001) with a mixture of potassium hydroxide and potassium ferrocyanide 50 ° C for 1 to 20 min. with vigorous stirring and illumination, the solution containing 6.5 to 10 wt. % potassium hydroxide and 3 to 7 wt. potassium ferrocyanide. When photo-etched with this mixture, crystallographic disturbances are visible on the surface of the material for times less than 1 minute. For times longer than 1 minute, faults are also visible inside the material. The mixture is also characterized by a memory effect, that is, even after etching of the failure, there remains a trace of the material in the form of a hole, groove, scoop and the like on the surface of the material.

The etching solution and its vapors do not cause harmful burns and do not damage the glass containers in which they are stored.

Example

A shiny semiconductor pad of indium phosphide InP, orientation (001), thickness 500 μπι was etched in a mixture containing 5 wt. % potassium ferrocyanide, 10 wt. % potassium hydroxide and 85 wt. of deionized water for 1.5 to 10 minutes.

The illumination was realized by means of a microscope objective, a 50 W halogen bulb. P 1 minute etching at dislocation penetration sites! small wells were etched with the surface of the material. Also, the wells were etched at other crystallographic disorders. After etching for 5 and 10 minutes, the dislocation wells were enhanced when the shoe dislocation was perpendicular to the surface. If the dislocation was oblique to the surface, this was manifested by etching the groove that followed the direction of the dislocation.

Claims (1)

SUBJECT A method of visualizing crystallographic disturbances in phosphide by indite InP orientation (001) by photo-etching, characterized in that indium phosphide is treated with a mixture composed of potassium hydroxide and potassium ferrocyanide in the form of an aqueous solution at 15 to 50 ° C for 1 to 20 min. . with vigorous stirring and illumination, the solution containing 6.5 to 10 wt. % potassium hydroxide and 3 to 7 wt. potassium ferrocyanide.