Abstract: The epitaxy sequentially includes from bottom to top a C-doped c-GaN high-resistance layer (11), an intrinsic u-GaN channel layer (12), an AlGaN barrier layer (13), a magnesium diffusion blocking layer (14), and a Mg-doped p-GaN cap layer (15) that are formed on a substrate (10). The magnesium diffusion blocking layer (14) includes a Mg-doped p-AlGaN layer (141). Mg in the Mg-doped p-AlGaN layer (141) is sufficiently passivated to in the Mg—H bond form, to reduce the activity of Mg. A doping concentration of Mg in the Mg-doped p-AlGaN layer (141) is greater than that of Mg in the Mg-doped p-GaN cap layer (15). A specific concentration difference of Mg is formed between them, so that Mg in the Mg-doped p-GaN cap layer (15) can be effectively blocked from diffusing downward into the AlGaN barrier layer (13) and the intrinsic u-GaN channel layer (12), thereby improving conducting performance of the device.

Abstract: The epitaxy sequentially includes from bottom to top a C-doped c-GaN high-resistance layer (11), an intrinsic u-GaN channel layer (12), an AlGaN barrier layer (13), a magnesium diffusion blocking layer (14), and a Mg-doped p-GaN cap layer (15) that are formed on a substrate (10). The magnesium diffusion blocking layer (14) includes a Mg-doped p-AlGaN layer (141). Mg in the Mg-doped p-AlGaN layer (141) is sufficiently passivated to in the Mg-H bond form, to reduce the activity of Mg. A doping concentration of Mg in the Mg-doped p-AlGaN layer (141) is greater than that of Mg in the Mg-doped p-GaN cap layer (15). A specific concentration difference of Mg is formed between them, so that Mg in the Mg-doped p-GaN cap layer (15) can be effectively blocked from diffusing downward into the AlGaN barrier layer (13) and the intrinsic u-GaN channel layer (12), thereby improving conducting performance of the device.

Abstract: The epitaxial structure sequentially includes from bottom to top a C-doped c-GaN high-resistance layer, a diffusion blocking layer, an intrinsic u-GaN channel layer, and an AlGaN barrier layer that are formed on a substrate. The diffusion blocking layer is a laminate structure or a superlattice structure; where the laminate structure comprises at least two layers selected from a group consisting of at least one Si3N4 layer, at least one AlN layer, and at least one GaN layer, and the laminate structure comprises at least one Si3N4 layer and also comprises at least one AlN layer or at least one GaN layer; where the superlattice structure is formed by periodically alternating laminate structures. The Si3N4 layer can block C atoms in the C-doped c-GaN high-resistance layer from diffusing into the intrinsic u-GaN channel layer. The AlN layer and the GaN layer provide growth transition for the diffusion blocking layer.