Integrated structure of trench gate mosfet and schottky diode with shielded gate

Abstract

The invention discloses an integrated structure of a trench gate MOSFET and a schottky diode based on a shielding gate, which is formed on a silicon substrate, and the formation areas of the trench gate MOSFET and the schottky diode are separated and adjacent. The trench gate MOSFET adopts a double-gate structure with a shielded gate, and the same trench structure as the trench gate is formed in the formation area of ​​the Schottky diode, and the front metal layer is filled to the top of the trench to form a Schottky diode Tertky contact, the front metal layer also forms a Schottky contact with the silicon epitaxial layer outside the trench, the structure of the trench side and the Schottky contact outside the trench can greatly increase the area of ​​the Schottky contact, and can greatly reduce The formation area of ​​the Schottky diode occupies the area of ​​the chip. At the same time, the Schottky diode of the present invention has nothing to do with the source contact hole using the trench contact hole, so the performance of the Schottky diode is not affected by the trench contact hole, and the process is relatively simple and easy to control.

Description

technical field [0001] The invention relates to a structure of a semiconductor integrated circuit device, in particular to an integrated structure of a trench gate MOSFET with a shield gate and a schottky diode. Background technique [0002] Integrating Schottky diodes in power MOS transistor devices can improve the cross-frequency characteristics of the devices, such as figure 1 Shown is a schematic diagram of the first integrated structure of an existing trench gate MOSFET with a shielded gate and a Schottky diode; the first integrated structure is formed on an N-type heavily doped silicon substrate, and on the silicon substrate The upper part is divided into a formation area 101 of a trench gate MOSFET and a formation area 102 of a Schottky diode. The formation area 101 of a trench gate MOSFET and the formation area 102 of a Schottky diode are separated and adjacent, and the adjacent positions are as figure 1 Shown at the dotted line AA in. [0003] The unit structure o...

AI Technical Summary

Problems solved by technology

[0020] The second type of integration structure is generally used in trench gate MOSFETs with small pitch and trench CT. Its advantage is that the Schottky diode is integrated in the contact hole, and no additional area or mask is required; its disadvantage is that the Schottky diode The leakage current and forward voltage drop (VF) of the tertiary diode are easily affected by the depth of the trench CT, and the process is difficult

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