Preparation method of Schottky diode

The invention discloses a Schottky diode preparation method, which comprises the following steps of: covering a first dielectric layer on the surface of a GaAs epitaxial wafer on which collector contact metal is deposited, and etching the first dielectric layer at a cathode position and an anode position to form a first through hole of the first dielectric layer; depositing first metal at the position of the cathode on the GaAs epitaxial wafer on which the first dielectric layer is formed; covering a second dielectric layer on the surface of the GaAs epitaxial wafer on which the first metal is deposited, and etching the second dielectric layer at the anode position to form a second through hole of the second dielectric layer; second metal is deposited at the position of the anode on the GaAs epitaxial wafer where the second dielectric layer is formed, a layer of Nitride is covered to isolate water vapor, a Schottky diode is formed, and the second metal is TPM capacitor upper pole plate metal; therefore, the t