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.