Ubiq Semiconductor Corp.

Chien-Ling Chan

Chi-Hsiang Lee

A trench gate MOSFET is provided. An epitaxial layer is disposed on a substrate. A body layer is disposed in the epitaxial layer. The epitaxial layer has a first trench therein, the body layer has a second trench therein, and the first trench is disposed below the second trench. A first insulating layer is disposed on a surface of the first trench. A second insulating layer is disposed in the first trench. A first conductive layer is disposed between the first and second insulating layers. A second conductive layer is disposed in the second trench. A third insulating layer is disposed between the second conductive layer and the body layer and between the second conductive layer and the first conductive layer. A dielectric layer is disposed on the epitaxial layer and covers the second conductive layer. Two doped regions are disposed in the body layer respectively beside the second trench.

Trench gate MOSFET

A trench gate MOSFET is provided. An epitaxial layer is disposed on a substrate. A body layer is disposed in the epitaxial layer. The epitaxial layer has a first trench therein, the body layer has a second trench therein, and the first trench is disposed below the second trench. A first conductive layer is disposed in the first trench. A first insulating layer is disposed between the first conductive layer and the epitaxial layer. A second conductive layer is disposed on a sidewall of the second trench. A second insulating layer is disposed between the second conductive layer and the body layer, and between the second conductive layer and the first conductive layer. A dielectric layer is disposed on the epitaxial layer and fills up the second trench. Two doped regions are disposed in the body layer respectively beside the second trench.

A method of forming a trench gate MOSFET is provided. An epitaxial layer is formed on a substrate. A trench is formed in the epitaxial layer. A first insulating layer is conformally formed on surfaces of the epitaxial layer and the trench. A first conductive layer is formed at the bottom of the trench. A portion of the first insulating layer is removed to form a second insulating layer exposing an upper portion of the first conductive layer. An oxidation process is performed to oxidize the first conductive layer to a third insulating layer, wherein a fourth insulating layer is simultaneously formed on the surface of the epitaxial layer and on the sidewall of the trench. A second conductive layer is formed in the trench. Two body layers are formed in the epitaxial layer beside the trench. Two doped regions are formed in the body layers respectively beside the trench.

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Hsinchu County, Taiwan

Chien-Ling Chan