Trench type power semiconductor devices with gate protrusion structures and their preparation methods

Abstract

The present invention discloses a trench type power semiconductor device with a gate protrusion structure and its preparation method. The preparation method comprises: depositing an epitaxial layer on a silicon substrate; Sequentially preparing a silicon dioxide pad layer, a first mask layer, and a second mask layer on the epitaxial layer; Etching to form gate trenches; Forming a gate oxide layer; Deposition of gate polycrystalline silicon; Remove the gate polycrystalline silicon on the surface of the first mask layer by chemical mechanical polishing; Etch and remove the first mask layer, and adjust the morphology of the gate polycrystalline silicon on the silicon platform region; Formation of body and source regions through ion implantation; Prepare source contact holes and tungsten plugs. In the present invention, a gate protrusion structure is formed during the preparation process of trench type power semiconductor devices, which solves the problem of increasing channel leakage after etching polycrystalline silicon. By increasing the cross-sectional area of the gate polycrystalline silicon, the gate resistance is reduced, the switching speed and linear region capability are improved, and the device performance is optimized.

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