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Method for preparing silicon carbide super-junction structure through laser etching

A laser etching and silicon carbide technology, which is applied in semiconductor/solid-state device manufacturing, electrical components, circuits, etc., can solve the problems of high difficulty in groove shape adjustment, low SiC efficiency, poor groove uniformity, etc., and achieve groove The side wall is smooth, the uniformity is good, and the aspect ratio is improved

Active Publication Date: 2016-04-27
INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the traditional plasma etching method etches SiC with low efficiency, complex process, poor groove uniformity, and high difficulty in groove shape adjustment.

Method used

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  • Method for preparing silicon carbide super-junction structure through laser etching
  • Method for preparing silicon carbide super-junction structure through laser etching
  • Method for preparing silicon carbide super-junction structure through laser etching

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Experimental program
Comparison scheme
Effect test

Embodiment approach

[0034] According to one embodiment of the present invention, the method for preparing a silicon carbide superjunction structure includes:

[0035] S1, using laser etching to pattern the silicon carbide epitaxial wafer to form grooves on the surface of the silicon carbide epitaxial wafer;

[0036] S2, growing silicon carbide epitaxially in the trench to form a silicon carbide superjunction structure, wherein the silicon carbide epitaxial wafer is one of an N-type epitaxial layer, a P-type epitaxial layer, and an N-type P-type mixed epitaxial layer. The impurity concentration range is 1×10 13 ~1×10 18 cm -3 , the doping type of the epitaxially grown silicon carbide is different from the doping type of the silicon carbide epitaxial wafer, the crystal form of the silicon carbide epitaxial wafer is 4H-SiC or 6H-SiC, the crystal form of the epitaxially grown silicon carbide is the same as that of the silicon carbide The epitaxial wafers have the same crystal form.

[0037] Accor...

Embodiment 1

[0047] Deposit 5-10 groups of Si on 4H-SiC wafer with N-type epitaxial layer 3 N 4 / SiO 2 Laminated to form a highly reflective layer, the total thickness is 700nm ~ 2um, such as, image 3 shown.

[0048] Through photolithography, the pattern required for laser etching is projected onto the photoresist on the surface of the SiC wafer to form a mask pattern, as shown in the attached Figure 4 shown.

[0049] Subsequently, under the mask of the photoresist, the highly reflective layer is etched by the ICP dry etching process. After the etching is completed, the photoresist is removed by the plasma stripping method, such as Figure 5 shown.

[0050] Subsequently, under the mask of the highly reflective layer, use a picosecond laser with a wavelength of 532nm and a pulse width of 10-800ps to etch SiC to the required depth, as Image 6 with 7 shown.

[0051] Subsequently, epitaxial growth is carried out in the SiC epitaxial furnace, and the P-type layer is uniformly grown t...

Embodiment 2

[0054] Deposit 5-10 groups of Si on 4H-SiC wafer with N-type epitaxial layer 3 N 4 / SiO 2 Laminated to form a highly reflective layer, the total thickness is 700nm ~ 2um, such as image 3 shown.

[0055] Through photolithography, the pattern required for laser etching is projected onto the photoresist on the surface of the SiC wafer to form a mask pattern, such as Figure 4 shown.

[0056] Subsequently, under the mask of the photoresist, the highly reflective layer is etched by the ICP dry etching process. After the etching is completed, the photoresist is removed by the plasma stripping method, such as Figure 5 shown.

[0057] Subsequently, under the mask of the highly reflective layer, use a picosecond laser with a wavelength of 532nm and a pulse width of 10-800ps to etch SiC to the required depth, as Image 6 with 7 shown

[0058] Subsequently, the Si on the SiC surface was removed by hydrofluoric acid buffer solution. 3 N 4 / SiO 2 Highly reflective layers such ...

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Abstract

The invention provides a method for preparing a silicon carbide super-junction structure. The method comprises the following steps: firstly carrying out graphical etching on silicon carbide epitaxial wafers by adopting laser etching so as to form grooves in the surfaces of the silicon carbide epitaxial wafers; and then carrying out epitaxial growth on silicon carbide in the grooves so as to form the silicon carbide super-junction structure. According to the method, the silicon carbide super-junction structure is prepared through the laser etching, the efficiency of forming the grooves in SiC through etching is obviously increased, the depth-to-width ratio is obviously promoted, and the structure also has the advantages of good uniformity, groove side wall smoothness, simple technology, high operability and the like.

Description

technical field [0001] The invention belongs to the field of semiconductors, in particular to a method for preparing a silicon carbide superjunction structure by laser etching silicon carbide. Background technique [0002] As the third-generation semiconductor material, silicon carbide (SiC) material has the characteristics of high critical breakdown electric field, high thermal conductivity, high saturation electron drift velocity, superior mechanical performance and physical and chemical stability. High frequency, high power, radiation resistance and other fields. Since the critical breakdown electric field strength of SiC is about ten times that of silicon, and the saturation electron drift speed is equivalent to that of silicon, the withstand voltage of SiC power devices can be higher than that of silicon, and the specific on-state resistance under the same breakdown voltage Also about one percent of silicon. [0003] Due to the limitation of silicon material character...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H01L21/04
CPCH01L29/66053
Inventor 刘胜北何志刘兴昉刘敏杨香樊中朝王晓峰王晓东赵有梅杨富华孙国胜曾一平
Owner INST OF SEMICONDUCTORS - CHINESE ACAD OF SCI
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