Structure for improving PN junction breakdown voltage and manufacturing method thereof

The invention provides a structure for improving PN junction breakdown voltage. The structure comprises a substrate; the N well and the P well are formed on the substrate, and the shallow trench isolation is used for isolating the N well from the P well. And the field plate structure is formed on the shallow trench isolation and is used for improving an electric field line at a PN junction so as to increase the breakdown voltage of the PN junction. The field plate structure is introduced, and the electric field line at the PN junction is improved, so that the junction isolation breakdown voltage is increased. 本发明提供一种提高PN结击穿电压的结构，包括衬底；形成于所述衬底上的N阱和P阱，以及用于隔离所述N阱和所述P阱的浅沟槽隔离；形成于所述浅沟槽隔离上的场板结构，其用于改善PN结处的电场线，以增加所述PN结的击穿电压。本发明引入场板结构，改善在PN结处的电场线，从而增加结隔离击穿电压。