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Trench field ring limiting terminal structure with variable side wall angle and preparation method

A terminal structure and field limiting ring technology, applied in the field of microelectronics, can solve the problems of high electric field and affecting device reliability, etc.

Inactive Publication Date: 2017-05-31
XIDIAN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In order to solve the above-mentioned problems existing in the prior art, the present invention provides a trench field-limiting ring termination structure with variable sidewall angles for silicon carbide power devices and a manufacturing method thereof to mainly solve the problem of the traditional planar surface of silicon carbide. The problem that the electric field at the edge of the terminal junction of the field limiting ring is too high and affects the reliability of the device

Method used

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  • Trench field ring limiting terminal structure with variable side wall angle and preparation method
  • Trench field ring limiting terminal structure with variable side wall angle and preparation method
  • Trench field ring limiting terminal structure with variable side wall angle and preparation method

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Embodiment 1

[0026] A trench field limiting ring termination structure with variable sidewall angles, specifically as figure 1 As shown, the silicon carbide substrate layer 101 is included, and the substrate layer has a doping concentration of 5×10 18 cm -3 Made of N-type SiC material with a thickness of 400 μm; the first semiconductor layer 102 is formed on the silicon carbide substrate layer 101, the first semiconductor layer 102 has the first conductivity type, and the doping concentration is 5×10 15 cm -3 , with a thickness of 15 μm; the surface of the first semiconductor layer 102 is provided with a plurality of trench structures, the angle between the trench sidewall 104 and the trench bottom 105 of each trench structure is 100°, and the upper part of each trench structure The width is 3 μm, the depth is 1 μm, and the distance between two adjacent trenches is 2 μm; a field-limiting ring structure 103 is provided under each trench structure, and the field-limiting ring structure 103...

Embodiment 2

[0035] A trench field limiting ring termination structure with variable sidewall angles, specifically as figure 2 As shown, the silicon carbide substrate layer 101 is included, and the substrate layer has a doping concentration of 5×10 18 cm -3Made of N-type SiC material with a thickness of 400 μm; the first semiconductor layer 102 is formed on the silicon carbide substrate layer 101, the first semiconductor layer 102 has the first conductivity type, and the doping concentration is 7×10 15 cm -3 , with a thickness of 10 μm; the surface of the first semiconductor layer 102 is provided with a plurality of groove structures, the angle between the groove sidewall 104 and the groove bottom 105 of each groove structure is 145°, and the upper part of each groove structure The width is 3.5 μm, the depth is 0.8 μm, and the distance between two adjacent trenches is 3 μm; a field limiting ring structure 103 is provided under each trench structure, and the field limiting ring structure...

Embodiment 3

[0039] A trench field limiting ring termination structure with variable sidewall angles, specifically as image 3 As shown, the silicon carbide substrate layer 101 is included, and the substrate layer has a doping concentration of 5×10 18 cm -3 Made of N-type SiC material with a thickness of 400 μm; the first semiconductor layer 102 is formed on the silicon carbide substrate layer 101, the first semiconductor layer 102 has the first conductivity type, and the doping concentration is 1×10 16 cm -3 , with a thickness of 5 μm; the surface of the first semiconductor layer 102 is provided with a plurality of groove structures, the angle between the groove sidewall 104 and the groove bottom 105 of each groove structure is 105°, and the upper part of each groove structure The width is 1.5 μm, the depth is 0.9 μm, and the distance between two adjacent grooves is 2.5 μm; a field limiting ring structure 103 is provided under each groove structure, and the field limiting ring structure...

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Abstract

The invention provides a trench field ring limiting terminal structure with a variable side wall angle. The trench field ring limiting terminal structure comprises a substrate layer and a first semiconductor layer which are sequentially stacked, a plurality of trench structures are arranged on the surface of the first semiconductor layer at intervals, an included angle between the trench side wall and the trench bottom of each trench structure is 90-145 degrees, a passivation layer covers the upper portions of the trench structures, a field ring limiting structure is arranged on the lower portion of each trench structure and arranged in the first semiconductor layer, field ring limiting structure below each trench structure is arranged and close to the trench side wall and the trench bottom and encircles the upper corresponding trench structure, and an active area is arranged in the first semiconductor layer and partially contacts with the passivation layer. According to the terminal structure, the trench structures of the variable side wall angle are added based on a traditional plane field ring limiting structure, the junction depth and the shape of a P-N junction of a field limiting ring is changed, junction edge curvature is improved, electric field concentration effect of the junction edge is relieved, and reliability of the field ring limiting terminal structure in reverse voltage resistance is improved.

Description

technical field [0001] The invention belongs to the technical field of microelectronics and relates to semiconductor devices, in particular to a trench field-limiting ring terminal structure with variable sidewall angles for silicon carbide power devices and a preparation method thereof. Background technique [0002] In recent years, with the continuous development of microelectronics technology, the application of Si-based power electronic devices in extreme environments such as high temperature, high pressure, and high humidity has become more and more restricted. As a representative of the third-generation semiconductor material, silicon carbide (SiC) material has a bandgap that is about three times that of silicon, a breakdown electric field that is eight times that of silicon, and thermal conductivity that is three times that of silicon. The withstand voltage capacity and current density of SiC devices are improved. Due to the different characteristics of the two mater...

Claims

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Application Information

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IPC IPC(8): H01L29/06H01L21/04
CPCH01L29/0619H01L21/0445
Inventor 宋庆文袁昊汤晓燕元磊张艺蒙张玉明
Owner XIDIAN UNIV