Trench type power semiconductor element and manufacturing method thereof

Abstract

The invention discloses a trench type power semiconductor element and a manufacturing method thereof. The trench gate structure of the trench type power semiconductor element comprises a shielding electrode, a grid electrode located above the shielding electrode, and an inter-electrode dielectric layer located between the shielding electrode and the grid electrode. Before forming the inter-electrode dielectric layer, the step of forming the trench gate structure at least comprises the step that a laminated structure is formed to cover the inner wall surface of the element trench, wherein the laminated structure at least comprises a semiconductor material layer and an initial inner dielectric layer for covering the semiconductor material layer; a heavily-doped semiconductor material is formed at the lower half part of the element trench; and a part of the initial inner dielectric layer on the upper half part of the element trench is removed, so as to expose the upper half part of the semiconductor material layer and the top of the heavily-doped semiconductor material. Therefore, the bottom of the grid electrode formed in the subsequent manufacturing process can be prevented from having a sharp angle.

Description

technical field [0001] The invention relates to a power semiconductor element and a manufacturing method thereof, in particular to a trench type power semiconductor element with a shielding electrode and a manufacturing method thereof. Background technique [0002] The working loss of the existing trench power metal oxide semiconductor field effect transistor (Power Metal Oxide Semiconductor Field Transistor, Power MOSFET) can be divided into two categories: switching loss and conducting loss. The capacitance value of the drain (Cgd) is an important parameter affecting the switching loss. If the gate / drain capacitance value is too high, it will increase the switching loss, and then limit the switching speed of the power MOSFET, which is not conducive to the application in high frequency circuits. [0003] Accordingly, the existing trench power metal oxide half field effect transistor will have a shielding electrode (shielding electrode) located in the lower half of the gate...

AI Technical Summary

Problems solved by technology

The two sharp corners 101 and 102 at the bottom of the gate 10 will lead to an increase in the electric field and reduce the withstand voltage of the trench power metal oxide semiconductor field effect transistor, thereby reducing the reliability of the device

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