Shield gate trench field effect transistor structure and preparation method thereof

Abstract

The invention provides a shield gate trench field effect transistor structure and a preparation method thereof. The first deep grooves and the second deep grooves are arranged in different deep grooves at intervals, so that the problem that the transistor is not synchronously turned on or turned off is avoided, and a plurality of resistors RDS (on) with the same resistance are connected in parallel; the total resistance is equivalent to RDS (on) / n, and n is the number of cells, so that the on-resistance is greatly reduced, and the static loss of the device is reduced; the bottom region of the first deep groove is filled with a BSG material, so the gate-drain overlapping area of the device is reduced, the gate-drain capacitance is reduced, the switching speed of the device is improved, and the dynamic loss of the device is reduced; the first P-type annular layer and the second P-type annular layer are respectively depleted with the N-type epitaxial layer, and the depletion layers of the adjacent first deep trench and second deep trench are communicated with each other along with the increase of the voltage, so that the drain-source leakage current Idss of the device is further reduced, the static loss of the device is reduced, and the soft breakdown is prevented; and the process steps are simple and the cost is low.

Description

technical field [0001] The invention belongs to the field of semiconductor device design and manufacture, and in particular relates to a structure of a shielded gate trench field effect transistor and a preparation method thereof. Background technique [0002] With the continuous development of semiconductor technology, the structure of metal oxide semiconductor field effect transistor (MOSFET) has also been continuously improved. Shielded gate trench field effect transistor (Split Gate Trench MOSFET, referred to as SGT-MOSFET) is one of the improved structures. By introducing a shielded gate structure, the gate-drain overlap area of ​​the device is reduced, thereby reducing the gate-drain capacitance to increase the switching speed. The purpose of reducing the dynamic loss of the device. Therefore, shielded gate trench MOS devices are widely used in various power electronic systems. [0003] At present, the shielded gate trench field effect transistor is divided into two ...

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Problems solved by technology

[0004] In view of the shortcomings of the prior art described above, the purpose of the present invention is to provide a shielded gate trench field effect transistor structure and its preparation method, which is used to solve the problem of the preparation process of the shielded gate trench field effect transistor with the upper and lower structures in the prior art. Complex, and shielded gate trench field effect transistors with left and right structures have problems such as asynchronous turn-on and turn-off states

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