Patterned substrate, formation method of patterned substrate and mask for producing patterned substrate

The invention provides a patterned substrate, which comprises a substrate and a periodic pattern which is arranged above the substrate. The periodic pattern consists of m+1 circular cone frustums, elliptical cone frustums or polygonal prism frustums which are sequentially stacked in steps from bottom to top, or consists of m circular cone frustums or elliptical cone frustums which are sequentially stacked in steps from bottom to top, and one circular cone frustum, elliptical cone frustum or polygonal prism frustum. Through the microstructure of the periodic pattern, stress caused by lattice mismatch between a GaN epitaxial layer or the like and the substrate, and dislocation density in the GaN epitaxial layer or the like can be reduced, the crystal quality of the GaN epitaxial layer or the like is improved and the brightness of an LED (light-emitting diode) is better improved. The invention additionally provides a mask consisting of a circular array, elliptical array or polygonal array. The internal part of each circular, elliptical or polygonal area in the array comprises m+1 concentric circular rings, concentric elliptical rings or concentric polygonal rings with different transmittances. The invention additionally provides a method for producing the patterned substrate by using the provided mask. The method is easy to realize and the cost is low.