CN115679451A - Method for ion-assisted chemical etching of silicon carbide - Google Patents
Method for ion-assisted chemical etching of silicon carbide Download PDFInfo
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- CN115679451A CN115679451A CN202211096214.4A CN202211096214A CN115679451A CN 115679451 A CN115679451 A CN 115679451A CN 202211096214 A CN202211096214 A CN 202211096214A CN 115679451 A CN115679451 A CN 115679451A
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Abstract
The invention provides a method for ion-assisted chemical etching of silicon carbide, which comprises the following steps: a) After annealing treatment is carried out on the single crystal silicon carbide, high-energy inert gas ions are injected into a specific pattern region on the surface of the single crystal silicon carbide by adopting an ion injection method to obtain ion-injected single crystal silicon carbide; b) And carrying out wet etching on the ion-implanted monocrystalline silicon carbide, and then cleaning and drying to obtain the etched silicon carbide. The invention provides a method for ion-assisted chemical etching of silicon carbide. The ion implantation modification and the chemical wet etching process are combined to realize the ion-assisted wet etching of the silicon carbide. The method can process the silicon carbide etching structure with micron and nanometer scale, has high manufacturing precision, only needs one time of ion implantation and one time of chemical wet etching, has simple manufacturing process and high efficiency, does not need to prepare a mask, does not need the matching of conditions such as vacuum, voltage, special gas and the like, and has low process complexity and high reliability.
Description
Technical Field
The invention belongs to the technical field of silicon carbide etching processing, and particularly relates to a method for chemically etching silicon carbide by ion assistance.
Background
Silicon carbide (SiC) is a third generation semiconductor material with superior performance. Compared with traditional semiconductor materials such as germanium and silicon, the silicon carbide has the advantages of wide band gap, high thermal conductivity, high saturation drift rate, high critical electric field intensity and other electrical properties. In addition, silicon carbide has excellent chemical stability, and thus is resistant to high temperature and corrosion. This makes silicon carbide based semiconductor devices have great potential for applications in harsh environments such as high temperature, high frequency, high voltage, high power, and strong radiation.
However, silicon carbide belongs to a hard and brittle material, the hardness of the silicon carbide is second to that of diamond, and the machining difficulty is high. Meanwhile, since silicon carbide has good chemical stability, it is still a relatively difficult problem to perform chemical etching on silicon carbide: the traditional wet etching method cannot effectively process the silicon carbide, and currently, a dry etching method is mostly adopted to process the silicon carbide, but the dry etching needs to be matched with a plurality of factors such as vacuum, voltage, special gas and the like, has high requirements on equipment structure, engineering technology level, matched experimental conditions and the like, and needs to manufacture an etching mask through previous procedures such as photoetching, film coating and the like, and has the disadvantages of high process flow complexity, more processing limiting conditions, and high cost and quality control difficulty. Therefore, it is desirable to provide a novel etching method with simple operation, effective control and low cost for processing silicon carbide.
Disclosure of Invention
In view of the above, the technical problem to be solved by the present invention is to provide a method for ion-assisted chemical etching of silicon carbide, which is simple, effective, controllable and low in cost.
The invention provides a method for ion-assisted chemical etching of silicon carbide, which comprises the following steps:
a) After annealing treatment is carried out on the single crystal silicon carbide, high-energy inert gas ions are injected into a specific pattern region on the surface of the single crystal silicon carbide by adopting an ion injection method to obtain ion-injected single crystal silicon carbide;
b) And carrying out wet etching on the ion-implanted monocrystalline silicon carbide, and then cleaning and drying to obtain the etched silicon carbide.
Preferably, the annealing temperature is 800-1500 ℃, and the annealing time is 2 min-2 h.
Preferably, the ion energy of the ion implantation is 1-200 keV; the energetic inert gas ions are selected from helium ions, neon ions or argon ions.
Preferably, the wet etchant of the wet etching is 40% HF and 33% H 2 O 2 The volume ratio of the mixed solution is 100. The corrosion time is 0.5 to 72 hours, preferably 1 to 10 hours; the temperature of the solution is between room temperature and 100 ℃ during corrosion.
Preferably, the wet etchant of the wet etching is 40% HF and 68% HNO 3 The volume ratio of the mixed solution is 50. The corrosion time is 0.5 to 72 hours, preferably 1 to 10 hours; the temperature of the solution is between room temperature and 100 ℃ during corrosion.
Preferably, the wet etchant for wet etching is a mixture of 40% by volume of HF and 37% by volume of HCl, in a volume ratio of 50. The corrosion time is 0.5 to 72 hours, preferably 1 to 10 hours; the temperature of the solution is between room temperature and 100 ℃ during corrosion.
Preferably, the wet etchant of the wet etching is 40% HF and 85% H 3 PO4 mixed solution, volume ratio 50. The corrosion time is 0.5 to 72 hours, preferably 1 to 10 hours; the temperature of the solution is between room temperature and 180 ℃ during corrosion.
Preferably, the cleaning is cleaning by sequentially soaking pure water, isopropanol or alcohol. The drying mode is nitrogen blow-drying or natural drying.
Compared with the prior art, the invention provides an ion-assisted chemical etching method for silicon carbide, which comprises the following steps: a) After annealing treatment is carried out on the single crystal silicon carbide, high-energy inert gas ions are injected into a specific pattern region on the surface of the single crystal silicon carbide by adopting an ion injection method to obtain ion-injected single crystal silicon carbide; b) And carrying out wet etching on the ion-implanted monocrystalline silicon carbide, and then cleaning and drying to obtain the etched silicon carbide. The invention provides a method for ion-assisted chemical etching of silicon carbide. The ion implantation modification and the chemical wet etching process are combined to realize the ion-assisted wet etching of the silicon carbide. The method can process the silicon carbide etching structure with micron and nanometer scale, has high manufacturing precision, only needs one ion injection and one chemical wet etching, and has simple manufacturing process, high efficiency, no need of preparing a mask, no need of matching conditions such as vacuum, voltage, special gas and the like, low process complexity and high reliability compared with the current common silicon carbide dry etching process.
Drawings
FIG. 1 is a flow chart of a method of ion-assisted etching of silicon carbide according to the present invention;
FIG. 2 is a schematic diagram of the process steps of the ion-assisted silicon carbide etching method provided by the present invention;
FIG. 3 is a photograph of a high resolution image after completion of the process of example 1;
FIG. 4 is a photograph of a high resolution image after completion of the process of example 2;
FIG. 5 is a photograph of a high resolution image after completion of the process of example 3.
Detailed Description
The invention provides a method for ion-assisted chemical etching of silicon carbide, which comprises the following steps:
a) After annealing treatment is carried out on the single crystal silicon carbide, high-energy inert gas ions are injected into a specific pattern region on the surface of the single crystal silicon carbide by adopting an ion injection method to obtain ion-injected single crystal silicon carbide;
b) And carrying out wet etching on the ion-implanted monocrystalline silicon carbide, and then cleaning and drying to obtain the etched silicon carbide.
The invention selects the single crystal silicon carbide as the substrate, and firstly carries out annealing treatment on the single crystal silicon carbide. The annealing apparatus according to the present invention is not particularly limited, and may be an annealing furnace, a rapid thermal annealing machine, an oxidation furnace, or LPCVD. In the present invention, the annealing temperature is 800 to 1500 ℃, preferably 800, 900, 1000, 1100, 1200, 1300, 1400, 1500, or any value between 800 and 1500 ℃; the annealing time is 2min to 120min, preferably 2, 3, 4, 5, 8, 10, 30, 60, 90, 120, or any value between 2min to 120 min.
Then, high-energy inert gas ions are implanted into the specific pattern region on the surface of the single crystal silicon carbide by adopting an ion implantation method to obtain the ion-implanted single crystal silicon carbide.
The ion beam implantation method is to implant high-energy inert gas ions with certain energy into a specific pattern region of a sample through an ion implantation device. The ion implantation equipment is selected from a focused ion beam microscope or an ion implanter, and the focused ion beam microscope is preferably a helium ion microscope; the shape of the specific pattern region of the injection sample can be a straight line, a curve, a rectangle, a circle, a ring, a polygon or an irregular shape, and the plane size can be 10nm to 500 μm, preferably 10nm, 50nm, 100nm, 500nm, 1 μm, 5 μm, 10 μm, 50 μm, 100 μm, 200 μm, 500 μm, or any value between 10nm and 500 μm. The ion energy is between 1 and 200keV, preferably 1, 5, 10, 20, 30, 40, 50, 60, 70, 80, 90, 100, 120, 140, 160, 180, 200, or any value between 1 and 200 keV. The energetic inert gas ions are selected from helium ions, neon ions or argon ions. The etching depth/ion implantation depth is determined by ion energy, and in the present invention, the etching depth corresponding to the ion energy of 1 to 200keV is 1 to 800nm, preferably 1, 5, 10, 50, 100, 200, 500, 800, or any value between 1 and 800 nm.
And after the ion implanted monocrystalline silicon carbide is obtained, carrying out wet etching on the ion implanted monocrystalline silicon carbide. Preferably, the wet etching is chemical wet etching.
In some embodiments of the invention, the wet etchant of the wet etch is 40% HF and 33% H 2 O 2 The volume ratio of the mixed solution is 100. The corrosion time is 0.5 to 72 hours, preferably 1 to 10 hours; the temperature of the solution is between room temperature and 100 ℃ during corrosion.
In some embodiments of the invention, the wet etchant of the wet etch is 40% HF and 68% HNO 3 The volume ratio of the mixed solution is 50. The corrosion time is 0.5 to 72 hours, preferably 1 to 10 hours; the temperature of the solution is between room temperature and 100 ℃ during corrosion.
In some embodiments of the present invention, the wet etchant for wet etching is a mixture of 40% hf and 37% hcl in a volume ratio of 50. The corrosion time is 0.5 to 72 hours, preferably 1 to 10 hours; the temperature of the solution is between room temperature and 100 ℃ during corrosion.
In some embodiments of the invention, the wet etchant of the wet etch is 40% HF and 85% H 3 PO4 mixed solution, volume ratio 50. The corrosion time is 0.5 to 72 hours, preferably 1 to 10 hours; the temperature of the solution is between room temperature and 180 ℃ during corrosion.
Finally, the single crystal silicon carbide is washed and dried. The method of washing and drying is not particularly limited in the present invention, and a method of washing and drying known to those skilled in the art may be used.
In the present invention, the cleaning is cleaning by sequentially immersing in pure water, isopropyl alcohol, or alcohol. The drying mode is nitrogen blow-drying or natural drying.
The invention provides a novel silicon carbide etching method, which combines ion implantation modification with a wet chemical etching process to realize ion-assisted chemical etching of silicon carbide. Can be used for processing and manufacturing silicon carbide micro-nano structures and devices.
Referring to fig. 1-2, fig. 1 is a flow chart of a method for ion-assisted etching of silicon carbide according to the present invention. Fig. 2 is a schematic process diagram of the ion-assisted silicon carbide etching method provided by the invention. Specifically, the single crystal silicon carbide substrate 1 is first annealed, and then implanted with a high energy inert gas ion beam 2 at a desired position and pattern on the surface of the silicon carbide, and the single crystal silicon carbide immediately below the implantation point is denatured due to the interaction of the inert gas ions with the silicon carbide, to form the amorphized region 3. And selectively corroding the region 3 by using a wet etching agent, cleaning and drying the sample to remove the residual wet etching agent, and finally obtaining an etched structure 4.
The invention provides a method for ion-assisted chemical etching of silicon carbide. The ion implantation modification and the chemical wet etching process are combined to realize the ion-assisted wet etching of the silicon carbide. The method can process the silicon carbide etching structure with micron and nanometer scale, has high manufacturing precision, only needs one time of ion implantation and one time of chemical wet etching, has simple manufacturing process and high efficiency compared with the prior common silicon carbide dry etching process, does not need to prepare a mask, does not need the matching of conditions such as vacuum, voltage, special gas and the like, and has low process complexity and high reliability.
For further understanding of the present invention, the method for ion assisted chemical etching of silicon carbide provided by the present invention is described below with reference to the following examples, and the scope of the present invention is not limited by the following examples.
Example 1:
step 1: the single crystal silicon carbide is annealed.
Step 2: the ion implantation method is used for implanting high-energy inert gas ions into a specific position area of the surface of the single crystal silicon carbide.
And step 3: and (3) corroding the sample obtained in the step (1) by using a wet etching agent to form an etching structure corresponding to the shape of the ion implantation area.
And 4, step 4: and (4) cleaning and drying the sample obtained in the step (3) to remove the residual wet etching agent.
Wherein, the annealing treatment of the single crystal silicon carbide in the step 1 is to anneal the silicon carbide by using a rapid thermal annealing machine, the annealing temperature is 900 ℃, and the annealing time is 4min.
The ion beam implantation method in step 2 is to implant high-energy helium ions into a specific position area of the sample by using a helium ion microscope. The ion energy was 30keV. The substrate material is single crystal silicon carbide.
Wherein the wet etchant in step 3 is 40% HF and 33% H 2 O 2 The solution was mixed in a volume ratio of 1:5. The etching time was 3 hours and the temperature was 80 ℃, the resulting etched structure is shown in fig. 3, fig. 3 is a high resolution image photograph of example 1 after processing, and the ion implanted region is a square with a side length of 1 μm.
Wherein, the cleaning mode in the step 4 is to soak pure water and isopropanol in sequence for cleaning. The drying mode is nitrogen blow drying.
Example 2:
step 1: the single crystal silicon carbide is annealed.
Step 2: the ion implantation method is used for implanting high-energy inert gas ions into a specific position area of the surface of the single crystal silicon carbide.
And step 3: and (3) corroding the sample obtained in the step (1) by using a wet etching agent to form an etching structure corresponding to the shape of the ion implantation area.
And 4, step 4: and (4) cleaning and drying the sample obtained in the step (3) to remove the residual wet etching agent.
Wherein, the annealing treatment of the single crystal silicon carbide in the step 1 is to anneal the silicon carbide by using a rapid thermal annealing machine, the annealing temperature is 900 ℃, and the annealing time is 4min.
The ion beam implantation method in step 2 is to implant high-energy helium ions into a specific position area of the sample by using a helium ion microscope. The ion energy was 10keV. The substrate material is single crystal silicon carbide.
Wherein the wet etchant in step 3 is 40% HF and 33% H 2 O 2 Mixing the solution in a volume ratio of 1. The etching time is 8h, the temperature is 80 ℃, the obtained etched structure is shown in figure 4, the figure 4 is a high-resolution imaging photo after the processing of the embodiment 2, and the ion implantation area is a straight line which is widened from left to right in a range of 10nm to 200nm (the line edge has certain widening after etching) and is 5 micrometers long.
Wherein, the cleaning mode in the step 4 is to soak pure water and isopropanol in sequence for cleaning. The drying mode is nitrogen blow drying.
Example 3:
step 1: the single crystal silicon carbide is annealed.
And 2, step: the ion implantation method is used for implanting high-energy inert gas ions into a specific position area on the surface of the single crystal silicon carbide.
And step 3: and (3) corroding the sample obtained in the step (1) by using a wet etching agent to form an etching structure corresponding to the shape of the ion implantation area.
And 4, step 4: and (3) cleaning and drying the sample obtained in the step (2) to remove the residual wet etching agent.
Wherein, the annealing treatment of the single crystal silicon carbide in the step 1 is to anneal the silicon carbide by using a rapid thermal annealing machine, the annealing temperature is 900 ℃, and the annealing time is 4min.
The ion beam implantation method in step 2 is to implant high-energy neon ions into a specific position region of the sample by using a focused ion beam microscope. The ion energy was 40keV. The substrate material is single crystal silicon carbide.
Wherein the wet etchant in step 3 is 40% HF and 68% HNO 3 Mixing the solution in a volume ratio of 10. The etching time was 0.5h, the temperature was 95 ℃, the resulting etched structure was as shown in FIG. 5, FIG. 5 is a photograph of a high resolution image after the processing of example 3 was completed, and the ion implanted regions were squares 2 μm in length and rectangles 2 μm × 1 μm in length.
Wherein, the cleaning mode in the step 4 is to soak pure water and absolute ethyl alcohol sequentially for cleaning. The drying mode is natural drying.
Example 4:
step 1: the single crystal silicon carbide is annealed.
Step 2: the ion implantation method is used for implanting high-energy inert gas ions into a specific position area of the surface of the single crystal silicon carbide.
And step 3: and (3) corroding the sample obtained in the step (1) by using a wet etching agent to form an etching structure corresponding to the shape of the ion implantation area.
And 4, step 4: and (4) cleaning and drying the sample obtained in the step (3) to remove the residual wet etching agent.
Wherein, the annealing treatment of the single crystal silicon carbide in the step 1 is to anneal the silicon carbide by using a rapid thermal annealing machine, the annealing temperature is 900 ℃, and the annealing time is 4min.
The ion beam implantation method in step 2 is to implant high-energy helium ions into a specific position area of the sample by using an ion implanter. The ion energy was 150keV. The substrate material is single crystal silicon carbide.
Wherein the wet etching agent in step 3 is 40% by volume of a mixed solution of HF and HCl 37% by volume of 1:1. The etching time is 1h, and the temperature is 70 ℃.
Wherein, the cleaning mode in the step 4 is soaking pure water and IPA cleaning in sequence. The drying mode is nitrogen blow drying.
Example 5:
step 1: the single crystal silicon carbide is annealed.
Step 2: the ion implantation method is used for implanting high-energy inert gas ions into a specific position area of the surface of the single crystal silicon carbide.
And step 3: and (3) corroding the sample obtained in the step (1) by using a wet etching agent to form an etching structure corresponding to the shape of the ion implantation area.
And 4, step 4: and (4) cleaning and drying the sample obtained in the step (3) to remove the residual wet etching agent.
Wherein, the annealing treatment of the single crystal silicon carbide in the step 1 is to anneal the silicon carbide by using a rapid thermal annealing machine, the annealing temperature is 900 ℃, and the annealing time is 4min.
The ion beam implantation method in step 2 is to implant high-energy argon ions into a specific position area of the sample by using an ion implanter. The ion energy was 80keV. The substrate material is single crystal silicon carbide. The implanted region was a 200 μm square.
Wherein the wet etchant in step 3 is 40% HF and 33% H 2 O 2 The solution was mixed in a volume ratio of 1:1. The etching time is 24h, and the temperature is 85 ℃.
Wherein, the cleaning mode in the step 4 is soaking pure water and IPA cleaning in sequence. The drying mode is nitrogen blow drying.
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (8)
1. A method for ion-assisted chemical etching of silicon carbide, comprising the steps of:
a) After annealing treatment is carried out on the single crystal silicon carbide, high-energy inert gas ions are injected into a specific pattern region on the surface of the single crystal silicon carbide by adopting an ion injection method to obtain ion-injected single crystal silicon carbide;
b) And carrying out wet etching on the ion-implanted monocrystalline silicon carbide, and then cleaning and drying to obtain the etched silicon carbide.
2. The method according to claim 1, wherein the annealing temperature is 800-1500 ℃ and the annealing time is 2 min-2 h.
3. The method of claim 1, wherein the ion implantation has an ion energy of 1 to 200keV; the energetic inert gas ions are selected from helium ions, neon ions or argon ions.
4. The method according to claim 1, wherein the wet etching agent of the wet etching is 40% of HF and 33% 2 O 2 The volume ratio of the mixed solution is 100. The corrosion time is 0.5 to 72 hours, preferably 1 to 10 hours; the temperature of the solution is between room temperature and 100 ℃ during corrosion.
5. The method according to claim 1, wherein the wet etching is carried out with a wet etchant which is 40% HF and 68% HNO 3 The volume ratio of the mixed solution is 50. The corrosion time is 0.5 to 72 hours, preferably 1 to 10 hours; the temperature of the solution is between room temperature and 100 ℃ during corrosion.
6. The method according to claim 1, wherein the wet etchant for wet etching comprises 40% by volume of a mixed solution of HF and 37% by volume of HCl, in a ratio of 50. The corrosion time is 0.5 to 72 hours, preferably 1 to 10 hours; the temperature of the solution is between room temperature and 100 ℃ during corrosion.
7. The method of claim 1, wherein the wet etching isThe wet etchant was 40% HF and 85% H 3 PO4 mixed solution, volume ratio 50. The corrosion time is 0.5 to 72 hours, preferably 1 to 10 hours; the temperature of the solution is between room temperature and 180 ℃ during corrosion.
8. The method according to claim 1, wherein the cleaning is a pure water, isopropyl alcohol or alcohol cleaning in sequence. The drying mode is nitrogen blow-drying or natural drying.
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| CN117393422A (en) * | 2023-12-11 | 2024-01-12 | 青禾晶元(天津)半导体材料有限公司 | Method for manufacturing silicon carbide composite substrate |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN117393422A (en) * | 2023-12-11 | 2024-01-12 | 青禾晶元(天津)半导体材料有限公司 | Method for manufacturing silicon carbide composite substrate |
| CN117393422B (en) * | 2023-12-11 | 2024-03-01 | 青禾晶元(天津)半导体材料有限公司 | Method for manufacturing silicon carbide composite substrate |
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