Semiconductor device with field threshold MOSFET for high voltage termination

摘要

This invention discloses a semiconductor power device disposed in a semiconductor substrate comprising a lightly doped layer formed on a heavily doped layer and having an active cell area and an edge termination area. The edge termination area comprises a plurality P-channel MOSFETs. By connecting the gate to the drain electrode, the P-channel MOSFET transistors formed on the edge termination are sequentially turned on when the applied voltage is equal to or greater than the threshold voltage Vt of the P-channel MOSFET transistors, thereby optimizing the voltage blocked by each region.

主权项

1. A semiconductor power device disposed in a semiconductor substrate comprising a lightly doped layer formed on top of a heavily doped layer and having an active cell area and an edge termination area wherein:
said edge termination area comprises a plurality of termination trenches formed in said lightly doped layer and lined with a dielectric layer and filled with a conductive material therein; and a plurality of series connected MOSFET transistors, each of which comprises a trench gate region, a drain and source regions disposed on two opposite sides of each of said termination trenches, with said conductive material in each of said termination trenches functions as a trench gate for each of said MOSFET transistors, wherein each trench gate is electrically connected to said drain region.