Preparation method for power diode

Abstract

A preparation method for a power diode, comprising: providing a substrate (), the substrate () having a front surface and a back surface opposite to the front surface, an N-type layer () growing on the front surface of the substrate (), and the N-type layer () having a first surface deviating from the substrate (); forming a terminal protection ring (); forming an oxide layer (), and performing knot pushing on the terminal protection ring (); conducting photoetching using a photoetching plate of an active region and etching the oxidation layer () of the active region, and forming a gate oxide layer () on the first surface of the N-type layer () of the active region; depositing on the gate oxide layer () to form a polysilicon layer (); conducting photoetching using a polysilicon photoetching plate, taking a photoresist () as a mask layer to inject P-type ions into the N-type layer (), and forming a P-type body region () beneath the polysilicon layer () through ion scattering; forming an N-type heavily doped region; forming a P+region; conducting thermal annealing, activating injected impurities and removing the photoresist (); and conducting metallization processing on the first surface and the back surface of the substrate ().