CN116247082A - Preparation method of heavily doped P-type silicon carbide wafer ohmic contact electrode - Google Patents

Preparation method of heavily doped P-type silicon carbide wafer ohmic contact electrode Download PDF

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CN116247082A
CN116247082A CN202310256466.7A CN202310256466A CN116247082A CN 116247082 A CN116247082 A CN 116247082A CN 202310256466 A CN202310256466 A CN 202310256466A CN 116247082 A CN116247082 A CN 116247082A
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silicon carbide
type silicon
carbide wafer
metal layer
heavily doped
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张泽盛
龚春生
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Beijing Crystal Field Semiconductor Co ltd
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Beijing Crystal Field Semiconductor Co ltd
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/40—Electrodes ; Multistep manufacturing processes therefor
    • H01L29/401—Multistep manufacturing processes
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/02—Semiconductor bodies ; Multistep manufacturing processes therefor
    • H01L29/12—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
    • H01L29/16—Semiconductor bodies ; Multistep manufacturing processes therefor characterised by the materials of which they are formed including, apart from doping materials or other impurities, only elements of Group IV of the Periodic Table
    • H01L29/1608—Silicon carbide
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00—Semiconductor devices specially adapted for rectifying, amplifying, oscillating or switching and having potential barriers; Capacitors or resistors having potential barriers, e.g. a PN-junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof ; Multistep manufacturing processes therefor
    • H01L29/40—Electrodes ; Multistep manufacturing processes therefor
    • H01L29/43—Electrodes ; Multistep manufacturing processes therefor characterised by the materials of which they are formed
    • H01L29/45—Ohmic electrodes
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    • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
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Abstract

The invention relates to the technical field of silicon carbide production, in particular to a preparation method of a heavily doped P-type silicon carbide wafer ohmic contact electrode. The embodiment of the invention provides a preparation method of an ohmic contact electrode of a heavily doped P-type silicon carbide wafer, which comprises the following steps: performing first sputtering treatment on a heavily doped P-type silicon carbide wafer to prepare a first aluminum metal layer on the P-type silicon carbide wafer; performing second sputtering treatment on the P-type silicon carbide wafer to obtain a second aluminum metal layer on the first aluminum metal layer; and annealing treatment is carried out to obtain the ohmic contact electrode of the heavily doped P-type silicon carbide wafer. The embodiment of the invention provides a preparation method of a heavily doped P-type silicon carbide wafer ohmic contact electrode, which can provide a heavily doped P-type silicon carbide wafer ohmic contact electrode with lower cost.

Description

Preparation method of heavily doped P-type silicon carbide wafer ohmic contact electrode
Technical Field
The invention relates to the technical field of silicon carbide production, in particular to a preparation method of a heavily doped P-type silicon carbide wafer ohmic contact electrode.
Background
Silicon carbide has excellent physical properties such as large forbidden bandwidth, high critical breakdown field strength, high saturated electron velocity, high thermal conductivity, stable chemical properties and the like, and is considered as an ideal material for preparing high-temperature, high-frequency and high-power semiconductor devices. The aim to realize large-scale preparation and application of silicon carbide devices is to solve the problem of forming good ohmic contact. Silicon carbide can be classified into N-type and P-type silicon carbide according to its conductivity type.
In the prior art, the research on the crystal growth of N-type silicon carbide is relatively mature, and a certain industrialization is formed. There has also been great development in N-type silicon carbide ohmic contacts, such as N-type silicon carbide ohmic contacts made of Ni-based metal having a specific contact resistance value of less than 10 -5 Ωcm 2 Magnitude, and have found wide application in device fabrication. Obtaining high quality P-type silicon carbide ohmic contacts relative to mature N-type silicon carbide ohmic contacts remains a challenge. At present, the P-type silicon carbide ohmic contact electrode mainly adopts an aluminum-titanium metal system. However, titanium is costly and is not suitable for industrial mass production.
Accordingly, in view of the above shortcomings, it is desirable to provide a method for fabricating an ohmic contact electrode for heavily doped P-type silicon carbide wafers.
Disclosure of Invention
The embodiment of the invention provides a preparation method of a heavily doped P-type silicon carbide wafer ohmic contact electrode, which can provide a heavily doped P-type silicon carbide wafer ohmic contact electrode with lower cost.
In a first aspect, an embodiment of the present invention provides a method for preparing an ohmic contact electrode of a heavily doped P-type silicon carbide wafer, including:
performing first sputtering treatment on a heavily doped P-type silicon carbide wafer to prepare a first aluminum metal layer on the P-type silicon carbide wafer;
performing second sputtering treatment on the P-type silicon carbide wafer to obtain a second aluminum metal layer on the first aluminum metal layer;
and annealing treatment is carried out to obtain the ohmic contact electrode of the heavily doped P-type silicon carbide wafer.
In one possible design, the power of the first sputtering process is (0.28-0.34) KV× (0.24-0.28) A for 25-35 min.
In one possible design, the second sputtering process has a power of 0.72KV by 0.02A for a period of 8-12 min.
In one possible design, the annealing treatment is performed at a temperature of 750-850 ℃ for a time of 1-2min.
In one possible design, the P-type silicon carbide wafer may have a doping concentration greater than or equal to 1.18X10 20 cm -3 。
In one possible design, the first sputtering process and the second sputtering process are each performed by applying a high temperature to metallic aluminum to evaporate the metallic aluminum to the P-type silicon carbide wafer;
before the first sputtering process, the method further comprises:
and performing pre-sputtering treatment on the metal aluminum to remove oxidized impurities on the surface of the metal aluminum.
In one possible design, the pre-sputter treatment time is 13 to 17 minutes.
In one possible design, the P-type silicon carbide wafer is covered with a reticle that is etched by photolithographic techniques to form a hollowed-out structure that matches the electrode pattern.
In one possible design, the first sputtering process and the second sputtering process are performed in a vacuum environment.
In a second aspect, an embodiment of the present invention further provides a heavily doped P-type silicon carbide wafer ohmic contact electrode, which is prepared according to any one of the preparation methods in the first aspect.
Compared with the prior art, the invention has at least the following beneficial effects:
and forming a first aluminum metal layer and a second aluminum metal layer on the P-type silicon carbide wafer through sputtering deposition by a first sputtering process and a second sputtering process. The first aluminum metal layer is wrapped by the second aluminum metal layer, and the second aluminum metal layer plays a role in protecting the first aluminum metal layer. The preparation materials of the first aluminum metal layer and the second aluminum metal layer are aluminum, so that the cost for producing the heavily doped P-type silicon carbide wafer ohmic contact electrode is reduced.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings that are required in the embodiments or the description of the prior art will be briefly described, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings may be obtained according to these drawings without inventive effort for a person skilled in the art.
FIG. 1 is a flow chart of a method for preparing an ohmic contact electrode of a heavily doped P-type silicon carbide wafer according to embodiment 1 of the present invention;
FIG. 2 is a schematic diagram of an ohmic contact electrode structure of a heavily doped P-type silicon carbide wafer according to embodiment 1 of the present invention;
FIG. 3 is a graph of test results for the products provided in example 1 and comparative examples 1, 2 of the present invention;
FIG. 4 is a graph of the specific contact resistivity calculation provided in example 1 of the present invention.
In the figure:
1-a first aluminum metal layer;
2-a second aluminum metal layer;
3-silicon carbide wafer.
Detailed Description
For the purpose of making the objects, technical solutions and advantages of the embodiments of the present invention more apparent, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention, and it is apparent that the described embodiments are some embodiments of the present invention, but not all embodiments, and all other embodiments obtained by those skilled in the art without making any inventive effort based on the embodiments of the present invention are within the scope of protection of the present invention.
In the description of embodiments of the present invention, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying any relative importance unless explicitly specified or limited otherwise; the term "plurality" means two or more, unless specified or indicated otherwise; the terms "connected," "secured," and the like are to be construed broadly, and may be, for example, fixedly connected, detachably connected, integrally connected, or electrically connected; can be directly connected or indirectly connected through an intermediate medium. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In the description of the present specification, it should be understood that the terms "upper", "lower", and the like used in the embodiments of the present invention are described in terms of the angles shown in the drawings, and should not be construed as limiting the embodiments of the present invention. In the context of this document, it will also be understood that when an element is referred to as being "on" or "under" another element, it can be directly on the other element or be indirectly on the other element through intervening elements.
The embodiment of the invention provides a preparation method of an ohmic contact electrode of a heavily doped P-type silicon carbide wafer, which comprises the following steps:
performing first sputtering treatment on the heavily doped P-type silicon carbide wafer to prepare a first aluminum metal layer on the P-type silicon carbide wafer;
performing second sputtering treatment on the P-type silicon carbide wafer to obtain a second aluminum metal layer on the first aluminum metal layer;
and annealing treatment is carried out to obtain the ohmic contact electrode of the heavily doped P-type silicon carbide wafer.
And forming a first aluminum metal layer and a second aluminum metal layer on the P-type silicon carbide wafer through sputtering deposition by a first sputtering process and a second sputtering process. The first aluminum metal layer is wrapped by the second aluminum metal layer, and the second aluminum metal layer plays a role in protecting the first aluminum metal layer. The preparation materials of the first aluminum metal layer and the second aluminum metal layer are aluminum, so that the cost for producing the heavily doped P-type silicon carbide wafer ohmic contact electrode is reduced. In addition, the first aluminum metal layer and the second aluminum metal layer are both composed of aluminum, so that the matching degree and the bonding degree of the first aluminum metal layer and the second aluminum metal layer are high.
Although the first sputtering process and the second sputtering process both form the aluminum metal layer, the power and time of the first sputtering process and the second sputtering process are different, and the thicknesses and the internal microstructures of the obtained first aluminum metal layer and the obtained second aluminum metal layer are different, so that the beneficial effects which are not possessed by a single aluminum layer can be obtained, and the heavily doped P-type silicon carbide wafer ohmic contact electrode can be obtained.
In some embodiments of the invention, the power of the first sputtering process is (0.28-0.34) KV× (0.24-0.28) A for 25-35 min.
In this example, the power of the first sputtering treatment was (0.28 to 0.34) kv× (0.24 to 0.28) a for 25 to 35 minutes, and a thicker first aluminum metal layer could be obtained.
In some embodiments of the invention, the second sputtering process is performed at a power of 0.72KV by 0.02A for a period of 8 to 12 minutes.
In this example, the second sputtering process was performed at a power of 0.72kv×0.02A for a period of 8 to 12 minutes, and a thinner second aluminum metal layer was obtained.
In some embodiments of the invention, the annealing treatment is performed at a temperature of 750-850 ℃ for a time of 1-2 minutes.
In this embodiment, the annealing process is lower in temperature and more energy efficient than prior art titanium containing schemes.
It should be noted that, the annealing temperature lower than 750 ℃ is unfavorable for the bonding between Al and SiC, because the melting point of Al is 700 ℃, and the temperature higher than 850 ℃ may cause the Al metal layer to be detached due to the excessive temperature.
In some embodiments of the invention, the doping concentration of the P-type silicon carbide wafer is greater than or equal to 1.18X10 20 cm -3 。
In the prior art, the heavily doped P-type silicon carbide wafer is difficult to prepare a high-quality ohmic contact electrode, and the preparation method provided by the invention can be applied to the preparation method with the doping concentration of more than or equal to 1.18 multiplied by 10 20 cm -3 The heavily doped P-type silicon carbide wafer has lower production cost. The concentration was lower than 1.18X10 20 cm -3 The method can be applied to P-type silicon carbide as well.
In some embodiments of the invention, the first sputtering process and the second sputtering process are each performed by applying a high temperature to metallic aluminum to evaporate the metallic aluminum to a P-type silicon carbide wafer;
before the first sputtering process is performed, further comprising:
and performing pre-sputtering treatment on the metal aluminum to remove oxidized impurities on the surface of the metal aluminum.
In this embodiment, oxidation may occur on the surface of the metal aluminum, and in order to obtain the high-quality first aluminum metal layer and the high-quality second aluminum metal layer, the metal aluminum needs to be subjected to a pre-sputtering treatment to remove impurities.
It is understood that the first sputtering process and the second sputtering process may use the same metal aluminum target, or may use two metal aluminum targets, respectively.
In some embodiments of the invention, the pre-sputter treatment is performed for a period of 13 to 17 minutes.
In this example, the impurities can be removed by a pre-sputter treatment for 13-17 min.
In some embodiments of the invention, the P-type silicon carbide wafer is covered with a reticle, and the reticle is etched to have a hollowed-out structure matching with the electrode pattern by a photolithography technique.
In some embodiments of the invention, the first sputtering process and the second sputtering process are performed in a vacuum environment.
The embodiment of the invention also provides a heavily doped P-type silicon carbide wafer ohmic contact electrode, which is prepared by the preparation method according to any one of the above embodiments.
Example 1
As shown in fig. 1, step (1), preparing a P-type silicon carbide wafer 3 with a certain doping concentration, and cleaning the surface of the silicon carbide wafer 3;
preparing a mask plate with an ohmic contact electrode pattern with a certain size by a photoetching technology, and tightly covering the mask plate on a cleaned silicon carbide wafer 3, and fixing the silicon carbide wafer on a sample stage of a magnetron sputtering instrument;
step (3), rotating the sample table to the middle of the two target placing positions (the target A and the target B), covering a cover of the magnetron sputtering cavity, vacuumizing, starting to adjust the air flow in the cavity after the vacuum degree reaches a preset value, and respectively pre-sputtering the target A and the target B for 15min;
after the pre-sputtering is completed, the sample stage is respectively and sequentially rotated to the positions above the target B and the target A, and then a first aluminum metal layer 1 and a second aluminum metal layer 2 are deposited on the surface of the silicon carbide wafer 3 through a first sputtering process and a second sputtering process, wherein the sputtering power of the first sputtering process and the second sputtering process is P respectively 1 And P 2 The time is 30min and 10min respectively;
step (5), performing rapid annealing treatment on the sputtered heavily doped P-type silicon carbide wafer 3 to finish the manufacture of the heavily doped P-type silicon carbide ohmic contact electrode, and obtaining the contact resistivity rho by a linear transmission line method c ＝5.1×10 -6 Ωcm 2 。
In step (1), the doping concentration of the P-type silicon carbide wafer 3 is about 1.18X10 20 cm -3 。
In the step (1), the surface cleaning treatment of the silicon carbide wafer 3 is required to include the following five steps:
(1) placing industrial alcohol with the purity of 75 percent and the silicon carbide wafer 3 into a beaker together, and then carrying out ultrasonic cleaning for 5-10min at normal temperature;
(2) the silicon carbide wafer 3 is cleaned for 25-30min by ultrasonic at 60-80 ℃ by utilizing a cleaning solution A, deionized water, ammonia water and hydrogen peroxide in the cleaning solution A are mixed according to the proportion of 5:1:1, preparing the mixture in proportion;
(3) the silicon carbide wafer 3 is cleaned for 25-30min by ultrasonic at 60-80 ℃ by utilizing a cleaning solution B, wherein deionized water, hydrochloric acid and hydrogen peroxide are mixed in the cleaning solution B according to the proportion of 6:1:1, preparing the mixture in proportion;
(4) the silicon carbide wafer 3 is cleaned by ultrasonic at 30 ℃ for 25-30min by using a cleaning solution C, wherein deionized water and hydrofluoric acid in the cleaning solution C are mixed according to the ratio of 10:1, preparing the mixture in proportion;
(5) and (3) ultrasonically cleaning the silicon carbide wafer 3 by using deionized water at 40-70 ℃ for 25-30min, and then taking out and drying.
The lithography technique in step (2) is laser etching.
In the step (3), the targets of the target A and the target B are round Al metal blocks with the purity of 99.99 percent and the size of phi 60 multiplied by 3mm respectively. On the other hand, the vacuum degree of the instrument reaches 4 multiplied by 10 -5 Pa, air flow is40sccm。
In the step (4), the sputtering power of the B target and the A target is P respectively 1 ＝0.32KV×0.26A,P 2 ＝0.72KV×0.02A。
In the step (5), the rapid annealing temperature is 750-850 ℃ and the time is 1-2min.
FIG. 2 is a schematic view of the electrode structure prepared in example 1;
curve 1 in fig. 3 is an I-V curve formed by annealing the electrode prepared in example 1, and it can be seen from curve 1 in fig. 3 that an obvious ohmic contact structure is formed between aluminum and silicon carbide in example 1.
FIG. 4 is a graph showing the total resistance between ohmic contact electrodes with the distance between electrodes according to the above-mentioned embodiment 1, and we obtain the contact resistivity of the electrodes as ρ by the linear transmission line method c ＝5.1×10 -6 Ωcm 2 It was demonstrated that ohmic contact electrodes of low contact resistivity can be obtained by the present invention.
Comparative example 1
Step (1), preparing a P-type silicon carbide wafer with a certain doping concentration, and cleaning the surface of the wafer;
preparing a mask plate with an ohmic contact electrode pattern with a certain size by a photoetching technology, and then tightly covering the mask plate on a cleaned silicon carbide wafer, and fixing the silicon carbide wafer and the silicon carbide wafer on a sample stage of a magnetron sputtering instrument;
step (3), rotating the sample table to one side above the target A, covering a cover of the magnetron sputtering cavity, vacuumizing, starting to adjust the air flow in the cavity after the vacuum degree reaches a preset value, and pre-sputtering the target A for 15min;
after the pre-sputtering is finished, turning a sample stage to the position right above the A target, and then depositing an Al metal layer on the surface of the silicon carbide wafer, wherein the sputtering power is 0.72KV multiplied by 0.02A, and the time is 40min;
and (5) carrying out rapid annealing treatment on the sputtered heavily-doped P-type silicon carbide wafer, and thus completing the manufacture of the heavily-doped P-type silicon carbide electrode.
Results and discussion: the electrode obtained by this method had a remarkable rectifying property (shown in curve 2 of fig. 3) as compared with example 1, and an ohmic contact electrode having a linear property was not obtained.
Comparative example 2
Step (1), preparing a P-type silicon carbide wafer with a certain doping concentration, and cleaning the surface of the wafer;
preparing a mask plate with an ohmic contact electrode pattern with a certain size by a photoetching technology, and then tightly covering the mask plate on a cleaned silicon carbide wafer, and fixing the silicon carbide wafer and the silicon carbide wafer on a sample stage of a magnetron sputtering instrument;
step (3), rotating the sample table to one side above the target B, then covering a cover of the magnetron sputtering cavity, vacuumizing, starting to adjust the air flow in the cavity after the vacuum degree reaches a preset value, and pre-sputtering the target A for 15min;
after the pre-sputtering is finished, turning a sample stage to the position right above a B target, and then depositing an Al metal layer on the surface of the silicon carbide wafer, wherein the sputtering power is 0.32KV multiplied by 0.26A, and the time is 40min;
and (5) carrying out rapid annealing treatment on the sputtered heavily-doped P-type silicon carbide wafer, and thus completing the manufacture of the heavily-doped P-type silicon carbide electrode.
Results and discussion: the electrode obtained by this method had rectifying characteristics (shown in curve 3 of fig. 2) compared with example 1, and did not obtain an ohmic contact electrode having linear characteristics, but was better than comparative example 1.
Comparative example 3
Comparative example 3 is substantially the same as example 1 except that the power of the first sputtering treatment is 0.5kv×0.26A.
The thickness of the first aluminum metal layer is larger due to higher power, and electrodes are adhered together during annealing, so that the formation of the electrodes is not facilitated.
Comparative example 4
Comparative example 4 was substantially the same as example 1 except that the power of the first sputtering treatment was 0.12kv×0.26A.
The smaller power makes the thickness of the first aluminum metal layer smaller, the thinner Al layer is quickly consumed during annealing, and an interface layer with a certain thickness cannot be formed on the SiC surface.
Comparative example 5
Comparative example 5 is substantially the same as example 1 except that the power of the first sputtering treatment is 0.32kv×0.6a.
The effect was similar to that of comparative example 3.
Comparative example 6
Comparative example 6 is substantially the same as example 1 except that the power of the first sputtering treatment is 0.32kv×0.1A.
The effect was similar to that of comparative example 4.
Comparative example 7
Comparative example 7 was substantially the same as example 1 except that the power of the second sputtering treatment was 1.2kv×0.02A.
The second aluminum metal layer has larger thickness due to higher power, and electrodes are adhered together during annealing, so that the formation of the electrodes is not facilitated.
Comparative example 8
Comparative example 8 was substantially the same as example 1 except that the power of the second sputtering treatment was 0.45kv×0.02A.
Because the second aluminum metal layer has smaller thickness due to smaller power, the thinner Al layer is quickly consumed during annealing, and effective protection cannot be formed on the first aluminum metal layer.
Comparative example 9
Comparative example 9 is substantially the same as example 1 except that the power of the second sputtering treatment is 0.72kv×0.04A.
The effect was similar to that of comparative example 7.
Comparative example 10
Comparative example 10 was substantially the same as example 1 except that the power of the second sputtering treatment was 0.72kv×0.005A.
The effect was similar to that of comparative example 8.
Comparative example 11
Comparative example 11 is substantially the same as example 1 except that the temperature of the annealing treatment is 600 ℃.
Since the annealing temperature is too low, al is in a solid state and cannot react with the SiC surface, which would be detrimental to the bond between the first aluminum metal layer and SiC.
Comparative example 12
Comparative example 12 is substantially the same as example 1 except that the temperature of the annealing treatment is 900 ℃.
The aluminum metal layer is peeled off due to the excessively high annealing temperature.
The aluminum metal layer includes a first aluminum metal layer and/or a second aluminum metal layer.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present invention, and are not limiting; although the invention has been described in detail with reference to the foregoing embodiments, it will be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims (10)

1. The preparation method of the ohmic contact electrode of the heavily doped P-type silicon carbide wafer is characterized by comprising the following steps of:
performing first sputtering treatment on a heavily doped P-type silicon carbide wafer to prepare a first aluminum metal layer on the P-type silicon carbide wafer;
performing second sputtering treatment on the P-type silicon carbide wafer to obtain a second aluminum metal layer on the first aluminum metal layer;
and annealing treatment is carried out to obtain the ohmic contact electrode of the heavily doped P-type silicon carbide wafer.
2. The method according to claim 1, wherein the power of the first sputtering treatment is (0.28 to 0.34) kv× (0.24 to 0.28) a for 25 to 35 minutes.
3. The method according to claim 1, wherein the power of the second sputtering treatment is 0.72KV x 0.02A for 8 to 12 minutes.
4. The method according to claim 1, wherein the annealing treatment is performed at a temperature of 750 to 850 ℃ for a time of 1 to 2 minutes.
5. The method of claim 1, wherein the P-type silicon carbide wafer has a doping concentration of 1.18 x 10 or greater 20 cm -3 。
6. The method of claim 1, wherein the first sputtering process and the second sputtering process are each performed by applying a high temperature to metallic aluminum to evaporate the metallic aluminum to the P-type silicon carbide wafer;
before the first sputtering process, the method further comprises:
and performing pre-sputtering treatment on the metal aluminum to remove oxidized impurities on the surface of the metal aluminum.
7. The method according to claim 6, wherein the pre-sputtering treatment is performed for 13 to 17 minutes.
8. The method of claim 1, wherein the P-type silicon carbide wafer is covered with a reticle, and the reticle is etched to have a hollowed-out structure matching the electrode pattern by photolithography.
9. The method of manufacturing according to claim 1, wherein the first sputtering process and the second sputtering process are performed in a vacuum environment.
10. An ohmic contact electrode of a heavily doped P-type silicon carbide wafer, which is prepared by the preparation method according to any one of claims 1 to 9.
CN202310256466.7A 2023-03-16 2023-03-16 Preparation method of heavily doped P-type silicon carbide wafer ohmic contact electrode Pending CN116247082A (en)

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