Shielding gate field effect transistor and forming method thereof and semiconductor device

Abstract

The invention provides a shielding gate field effect transistor and a forming method thereof and a semiconductor device. A sacrificial layer is used for forming a first dielectric layer in a lower trench of a trench to form a trench with a wide upper part and a narrow lower part, so that the generated gap can be controlled to be positioned in the lower trench part when an electrode material layeris filled, the influence of the gap on the etching process of the electrode material layer is avoided, and the performance of the formed transistor device is guaranteed. Furthermore, according to theforming method provided by the invention, as a gap can be allowed to be generated in the electrode material layer, the side wall of the trench can be a vertical side wall or a side wall close to the vertical side wall, and the size reduction of a transistor device is facilitated.

Description

technical field [0001] The invention relates to the technical field of image sensors, in particular to a shielded gate field effect transistor, a forming method thereof, and a semiconductor device. 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] Wherein, the forming method of the shielded gate field effect tran...

AI Technical Summary

Problems solved by technology

[0005] The object of the present invention is to provide a method for forming a shielded gate field effect transistor, so as to solve the problem of uneven etching caused by the existence of gaps in the preparation process of the shielded electrode, which affects the morphology of the shielded electrode.

Images