Trench DMOS device with improved termination structure for high voltage applications

摘要

A termination structure for a power transistor includes a semiconductor substrate having an active region and a termination region. The substrate has a first type of conductivity. A termination trench is located in the termination region and extends from a boundary of the active region to within a certain distance of an edge of the semiconductor substrate. A doped region has a second type of conductivity disposed in the substrate below the termination trench. A MOS gate is formed on a sidewall adjacent the boundary. The doped region extends from below a portion of the MOS gate spaced apart from the boundary toward a remote sidewall of the termination trench. A termination structure oxide layer is formed on the termination trench and covers a portion of the MOS gate and extends toward the edge of the substrate. A first conductive layer is formed on a backside surface of the semiconductor substrate. A second conductive layer is formed atop the active region, an exposed portion of the MOS gate, and extends to cover at least a portion of the termination structure oxide layer.

主权项

1. A termination structure for a power transistor, said termination structure comprising:
a semiconductor substrate having an active region and a termination region, the substrate having a first type of conductivity; a termination trench located in the termination region and extending from a boundary of the active region to within a certain distance of an edge of the semiconductor substrate; a doped region having a second type of conductivity disposed in the substrate below the termination trench; a MOS gate formed on a sidewall adjacent the boundary, wherein the doped region extends from below a portion of the MOS gate spaced apart from the boundary toward a remote sidewall of the termination trench; a termination structure oxide layer formed on the termination trench covering a portion of the MOS gate and extending toward the edge of the substrate, the termination structure oxide layer and the doped region being in contact with one another and defining an interface therebetween; a first conductive layer formed on a backside surface of the semiconductor substrate; and a second conductive layer formed atop the active region, an exposed portion of the MOS gate, and extending to cover at least a portion of the termination structure oxide layer.