Mos diode with termination structure and method for manufacturing the same

Abstract

A MOS diode includes a substrate with a mesa, a P-type semiconductor region with etched shallow trench surrounding the mesa, that cause an increasing metal contact area to reduce Vf value, a gate oxide layer arranged on the mesa, a polysilicon layer arranged on the gate oxide layer, and a shielding oxide layer arranged on the polysilicon layer. The termination structure includes a trench, an oxide layer arranged at least within the trench, at least one sidewall polysilicon layer arranged on the oxide layer within the trench. In the MOS diode, the shielding oxide layer is thicker than the gate oxide layer to prevent leaking current. The oxide layer and the sidewall polysilicon layer can enhance the reverse voltage tolerance of the MOS diode. A metal layer covers the polysilicon region, shielding oxide layer, semiconductor regions with etched shallow trench, termination region and some parts outside the termination region.