Process method for improving cell density of trench MOSFET and trench MOSFET structure

A process method and groove technology, applied in the direction of electrical components, transistors, electric solid devices, etc., can solve the problem of large on-resistance, and achieve the best avalanche current characteristics, uniform threshold voltage and on-resistance effects

CN112103186AActive Publication Date: 2020-12-18深圳市芯电元科技有限公司
6 Cites 4 Cited by

Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2020-12-18

Smart Images

  • Figure 1
    Figure 1
  • Figure 2
    Figure 2
  • Figure 3
    Figure 3
Patent Text Reader

Abstract

The invention discloses a process method for improving the cell density of a trench MOSFET and a trench MOSFET structure. The method comprises the following steps: depositing polycrystalline silicon,removing the polycrystalline silicon outside a trench, removing first silicon nitride, forming a first doped region and a third doped region in an epitaxial layer, depositing second silicon nitride, etching the second silicon nitride, and forming side walls on the side walls of the polycrystalline silicon, wherein the widths of the side walls formed by the left side wall and the right side wall ofthe polycrystalline silicon are equal; injecting boron atoms or phosphorus atoms into the first doped region to form a second doped region, wherein the doping concentration of the second doped regionis 20-100 times that of the first doped region, removing the side walls, removing polycrystalline silicon protruding out of the surface of the first oxide layer, depositing a dielectric layer, removing the dielectric layer and silicon in a set region, and forming source region contact holes. The process method for improving the cell density of the trench MOSFET and the trench MOSFET structure provided by the invention have the advantages of being capable of realizing more uniform threshold voltage and conduction resistance and the like.
Need to check novelty before this filing date? Find Prior Art

Description

technical field

[0001] The invention relates to the technical field of semiconductors, in particular to a process method for increasing the cell density of a trench MOSFET and a trench MOSFET structure. Background technique

[0002] The MOSFET chip is a discrete device, which belongs to the category of semiconductor power devices, and belongs to the field of semiconductor chips with integrated circuits. The most critical index parameters of MOSFETs include breakdown voltage (especially drain-source breakdown voltage), on-resistance and threshold voltage ( It is also called turn-on voltage in spoken language), usually, the larger the breakdown voltage, the better, and the smaller the on-resistance, the better. In order to achieve its nominal breakdown voltage, the internal structure of the MOSFET chip uses an epitaxial layer with a specific resistivity and a specific thickness to bear the pressure. Usually, the higher the breakdown voltage required to achieve, the resistivity...

Examples

Embodiment Construction

[0046] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are some of the embodiments of the present invention, but not all of them. Based on the embodiments of the present invention, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present invention.

[0047] It should also be understood that the terminology used in the description of the present invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the present invention. As used in this specification and the appended claims, the singular forms "a", "an" and "the" are intended to include plural referents unless the context clearly dictates otherwise.

[0048] It should also be further unders...