GaN-based epitaxial material dislocation defect determination method

The invention discloses a GaN-based epitaxial material dislocation defect determination method. The GaN-based epitaxial material dislocation defect determination method comprises the following steps of heating a phosphoric acid solution or a mixed solution of phosphoric acid and sulfuric acid until the solution is boiling, putting a gallium nitride sample into the boiling acid for corrosion lasting for 20-30min, taking out the sample, carrying out chemical cleaning on the sample, carrying out drying, observing the sample by a fluorescence microscope, switching a light source of the fluorescence microscope into a powerful light source, setting a dark field mode, wherein the material surface observed by an eyepiece has a black color, inclined planes and bottoms of pits formed by dislocation and having different sizes reflect incident light so that light spots with different sizes are formed, calculating the number of the light spots on the sample to obtain the total numbers of different dislocations, and calculating corresponding dislocation density by dividing the corresponding total number of dislocation by the observation area at the amplification multiple. The method utilizes combination of boiling acid chemical etching and a dark field fluorescent microscope technology, and utilizes powerful light source-produced light spots with different sizes at different dislocation defect positions under the dark field condition to determine the dislocation.