Method for detecting defect of single crystal structure of gallium arsenide in large size

Abstract

The invention is a defect detecting method for a large-size GaAs monocrystalline structure, comprising: grinding and polishing, i.e. mechanically or chemically polishing, where the formula of the adopted polishing solution is that the ratio of sulphuric acid to oxydol to water is 3 : 1 : 1; dislocation corroding, i.e. placing potassium hydroxide in a silver pot and heating to melt potassium hydroxide into a clear state and immediately placing the clear-state potassium hydroxide in a wafer sample for corroding, then taking out the sample and cooling, and then washing with water and blow-dry; selecting measuring direction, measuring point position and number of measuring points, observing visual field area, where the first measuring point is D / 10mm apart from the wafer edge and the others are selected at 10 mm intervals, each of which is a measuring visual field; calculating for the selected measuring points. The invention enlarges the range of dislocation density detection, convenient and simple to operate and saving time.

Description

[0001] Field [0002] The invention relates to a method for detecting structural defects of gallium arsenide single crystals applied in the field of semiconductors, in particular to a method for detecting dislocation density of large-scale gallium arsenide single crystals. Background technique [0003] Dislocations are revealed using selective chemical etching techniques. The lattice around the dislocation lines in the crystal is distorted, and the outcrops on the crystal surface are preferentially corroded by certain chemical etchants. Therefore, it is easy to form an angular corrosion pit or hillock with a specific shape composed of some low-index surfaces at the outcrop of defects on a certain crystal surface of the crystal. [0004] At present, the steps of the existing method for detecting the dislocation density of GaAs single crystal are as follows: grinding, polishing, etching, testing and calculating the cut GaAs single wafer. When etching the wafer, it needs to be h...

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Problems solved by technology

[0004] At present, the steps of the existing method for detecting the dislocation density of GaAs single crystal are as follows: grinding, polishing, etching, testing and calculating the cut GaAs single wafer. When etching the wafer, it needs to be heated by potassium hydroxide The sample can only be corroded when the temperature is 400°±5°C, which requires a thermometer to measure, so that the corrosion time of a large-scale gallium arsenide single wafer is controlled by the existing method, and the corrosion effect is not clear, not ideal, or even uncountable It will bring a large detection error, which directly affects the measurement accuracy, and also increases the measurement time and the complexity of the measurement operation; when testing after corrosion, the selection method of the measurement point in the existing method is D / 10mm, where D is the diameter of the gallium arsenide single chip, that is, a measurement point is selected every D / 10mm. When the diameter of the gallium arsenide single chip is small, this selection method is still acceptable, but when the diameter of the gallium arsenide single chip increases, This selection method causes the selection of measurement points to be too wide, the number of measurement points is reduced, and the detection accuracy cannot meet the requirements.

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