Shield gate field effect transistor and forming method thereof

Abstract

The invention provides a shield gate field effect transistor and a forming method thereof. After a first dielectric layer and a shielding electrode are sequentially formed, the part, higher than the shielding electrode, of the first dielectric layer is directly etched, and thus, the thickness of the etched first dielectric layer is gradually reduced from bottom to top at the part higher than the shielding electrode, the morphology of the upper groove positioned above the shielding electrode can be modified, the filling difficulty of the insulation filling layer can be reduced, the filling performance of the insulation filling layer in the upper groove is improved, gaps are avoided, and when the insulation filling layer is subsequently etched to form the isolation layer, the isolation layerwithout gaps can be formed, and mutual isolation between the gate electrode and the shielding electrode is guaranteed.

Description

technical field [0001] The invention relates to the technical field of semiconductors, in particular to a shielded gate field effect transistor and a forming method thereof. Background technique [0002] A shielded gate field effect transistor (Shielded Gate Trench, SGT) is more conducive to the flexible application of semiconductor integrated circuits because of its low gate-to-drain capacitance Cgd, very low on-resistance, and high withstand voltage performance. Specifically, in the shielded gate field effect transistor, by setting the shielding electrode below the gate electrode, the gate-to-drain capacitance can be greatly reduced, and the drift region of the shielded gate field effect transistor also has a relatively high impurity carrier Concentration, can provide additional benefits to the breakdown voltage of the device, which can reduce the on-resistance accordingly. [0003] Compared with other trench field effect transistors, shielded gate field effect transistor...

AI Technical Summary

Problems solved by technology

[0004] The purpose of the present invention is to provide a method for forming a shielded gate field effect transistor to solve the problem of easy short circuit between the gate electrode and the shielding electrode in the existing shielded gate field effect transistor

Images