TRENCH POWER MOSFET WITH REDUCED ON-RESISTANCE

摘要

PURPOSE: A trench power MOSFET(Metal Oxide-Semiconductor Field Effect Transistor) having reduced on-resistance is provided to produce rugged trench power MOSFET devices by forming a thick dielectric layer between a gate and a shield poly. CONSTITUTION: An active trench(215) is extended to the inside of a drift region through a well region. Sidewalls of the active trench and a part of a lower surface are lined with a dielectric material. A shield portion(225) is separated from the sidewalls of the active trench by the dielectric material. A gate(235) is arranged on the shield portion and separated by the dielectric material between electrodes. A source region(240) is formed within the well region which is contiguous to the active trench. The gate is separated from the sidewalls of the active trench by the dielectric material. The shield portion and the gate are composed of materials having different work functions.