Method for improving uniformity and wavelength concentration degree inside 4-inch GaN-based epitaxy epitaxial wafer

A method for improving the uniformity and wavelength concentration degree inside a 4-inch GaN-based epitaxy epitaxial wafer is provided. The growth method of a buffer layer in the GaN-based epitaxy epitaxial wafer comprises the following steps that: (1) after high-temperature cleaning is performed on the surface of a 4-inch substrate under hydrogen atmosphere, nitridation treatment is performed on the surface of the 4-inch substrate; (2) after the nitridation treatment, the growth of an ALxGa1-xN buffer layer with a fixed AL component is carried out, and the thickness of the ALxGa1-xN buffer layer is maintained from 0 nm to 10 nm; (3) after the growth of the ALxGa1-xN buffer layer with the fixed AL component is finished, the growth of a GaN thin layer is carried out, and the thickness of the GaN thin layer is maintained from 0 nm and 5 nm; (4) the growth of the ALxGa1-xN buffer layer with the fixed AL component which is carried out in the step (2) and the growth of the GaN thin layer which is carried out in the step (3) are performed alternately for 5 to 20 cycles; and (5) after the growth of the buffer layer is finished, the growth of the other layers is performed. With the method adopted, the defect density of a quantum well region can be effectively reduced, and a high-uniformity and high-wavelength concentration degree epitaxial wafer can be obtained.