Transistor device and manufacturing method thereof

Abstract

A transistor device and a manufacturing method thereof are provided. The transistor device includes a silicon carbide substrate, a silicon carbide epitaxial layer, a gate trench and a double-layer gate dielectric layer. The silicon carbide epitaxial layer is disposed on the silicon carbide substrate. The gate trench is disposed in the silicon carbide epitaxial layer. The double-layer gate dielectric layer has a bottom gate dielectric layer and a sidewall gate dielectric layer, wherein the bottom gate dielectric layer is disposed on a bottom surface of the gate trench, and the sidewall gate dielectric layer is disposed on a sidewall surface of the gate trench above the bottom gate dielectric layer, and a thickness of the bottom gate dielectric layer is greater than that of the sidewall gate dielectric layer.

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