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 power semiconductor device includes a shielding electrode, a gate above the shielding electrode, and an interelectrode dielectric layer between the shielding electrode and the gate. Before forming the inter-electrode dielectric layer, the step of forming the trench gate structure at least includes: forming a stacked structure covering the inner wall surface of the device trench, wherein the stacked structure includes at least a semiconductor material layer and a covering semiconductor material layer forming a heavily doped semiconductor material in the lower half of the element trench; and removing a part of the initial inner dielectric layer located in the upper half of the element trench to expose an upper half of the semiconductor material layer part and the top of the heavily doped semiconductor material. In this way, sharp corners at the bottom of the gate formed in the subsequent manufacturing process can be avoided.

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

Images