MPS diode device and preparation method therefor

A preparation method of an MPS diode device, comprising:

• forming an epitaxial layer on a substrate, wherein a side of the epitaxial layer away from the substrate comprises an active layer formation region for forming an active region;
• forming the active region in the active formation region;
• annealing treatment;
• forming a buffer layer on a side of the epitaxial layer away from the substrate, and a band gap of the buffer layer being greater than a band gap of the epitaxial layer, and patterning a part of the buffer layer corresponding to the active region to form a first hole passing through the buffer layer;
• forming an ohmic metal layer in the first hole;
• forming a cathode electrode on a side of the substrate away from the epitaxial layer;
• and
• forming an anode electrode on a side of both of the buffer layer and the ohmic metal layer away from the epitaxial layer.