Silicon carbide power device terminal and manufacturing method therefor

Abstract

The invention provides a manufacturing method of a silicon carbide power device terminal. The manufacturing method comprises the steps of 1, providing an N<+>-SiC substrate, and forming an N<->-SiC epitaxial layer on the N<+>-SiC substrate; 2, preparing P type main junctions, P type field limiting rings, a P-i-N structure and N type cut-off rings in the N<->-SiC epitaxial layer, wherein shallow grooves are etched in the P type main junctions and the P type field limiting rings, and the shallow grooves are filled with a dielectric layer; the P-i-N structure is positioned between the P type mainjunctions and the adjacent P type field limiting rings, and in the N<->-SiC epitaxial layer between adjacent P type field limiting rings; and the P-i-N structure comprises a P type doped region and an N type doped region which are distributed in a direction parallel to the terminal surface and parallel to the P type main junctions; and 3, depositing a passivation layer for covering the terminalsurface on the surface of the N<->-SiC epitaxial layer. The invention also provides the silicon carbide power device terminal. By virtue of the manufacturing method, the breakdown voltage and reliability of the device can be improved.

Description

Technical field [0001] The invention relates to the technical field of semiconductor devices, in particular to a silicon carbide power device terminal and a manufacturing method thereof. Background technique [0002] Modern technology continuously puts forward higher requirements on the volume, reliability, withstand voltage, and power consumption of semiconductor power devices. With the shrinking of the feature size of transistors, due to physical laws such as short-channel effects and restrictions on production costs, mainstream silicon-based materials and CMOS technologies are developing to the 10nm process node and it is difficult to continue to improve. [0003] The third-generation semiconductor material silicon carbide (SiC) has a larger band gap and a higher critical breakdown field strength than silicon. Compared with silicon power devices of the same withstand voltage level, SiC has a higher doping concentration and more The thickness of the epitaxial layer is small, so ...

AI Technical Summary

Problems solved by technology

[0005] However, due to the high surface electric field of SiC power devices, in order to improve the withstand voltage, it is necessary to reduce the surface peak electric field during device design, requiring the design of a large number of field limiting loops

Therefore, there are many factors to be considered in the design, such as the number of field limiting rings, the ring width, the distance between each field limiting ring, etc.; and the terminal with multiple field limiting rings occupies a large chip area, which is not conducive to increasing the current

However, there is a figure of merit concentration in the junction terminal extension structure and the breakdown voltage of the device is sensitive to the figure of merit concentration, so the design window is relatively small; and the junction terminal extension structure is very sensitive to the surface charge, which is easily caused by interface instability and oxide layer charge. Thus affecting the electric field distribution on the surface of the device, which in turn affects the breakdown voltage and reliability of the device

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