Method for epitaxial growth of GaN thin film material

A method for epitaxial growth of a GaN thin film material comprises the steps of providing a substrate; forming a buffer layer on a surface of the substrate; forming a GaN sub-layer on the buffer layer; etching a part of the GaN sub-layer; and repeating the steps of forming the GaN sub-layer and etching a part of the GaN sub-layer for many times, and forming a GaN layer on a surface of the buffer layer. With the method, the GaN layer with low dislocation density and high crystal quality can be formed. 种氮化镓薄膜材料外延生长的方法，包括：提供衬底；在所述衬底表面形成缓冲层；在所述缓冲层上形成氮化镓子层；刻蚀部分所述氮化镓子层；多次重复所述形成所述氮化镓子层以及刻蚀部分所述氮化镓子层的步骤，在所述缓冲层表面形成氮化镓层。上述方法可以形成低位错密度、高晶体质量的氮化镓层。