Epitaxial method for improving breakdown voltage of GaN-based power device

The invention relates to an epitaxial method for improving a breakdown voltage of a GaN-based power device. The epitaxial method comprises the steps of providing a substrate; forming a buffer layer on a surface of the substrate by an atomic layer deposition process; and forming a GaN layer on a surface of the buffer layer. With the method, the quality of formed GaN can be improved. 种提高氮化镓基功率器件击穿电压的外延方法，所述外延方法包括：提供衬底；采用原子层沉积工艺，在所述衬底表面形成缓冲层；在所述缓冲层表面形成氮化镓层。上述方法可以提高形成的氮化镓的质量。