CN114784096A - GaN-based high electron mobility transistor, ohmic metal electrode and preparation method thereof - Google Patents

GaN-based high electron mobility transistor, ohmic metal electrode and preparation method thereof Download PDF

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CN114784096A
CN114784096A CN202210230849.2A CN202210230849A CN114784096A CN 114784096 A CN114784096 A CN 114784096A CN 202210230849 A CN202210230849 A CN 202210230849A CN 114784096 A CN114784096 A CN 114784096A
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layer
gan
metal electrode
ohmic metal
ohmic
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刘明远
郑英奎
康玄武
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Institute of Microelectronics of CAS
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    • H01L21/28—Manufacture of electrodes on semiconductor bodies using processes or apparatus not provided for in groups H01L21/20 - H01L21/268
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    • H01L29/66446—Unipolar field-effect transistors with an active layer made of a group 13/15 material, e.g. group 13/15 velocity modulation transistor [VMT], group 13/15 negative resistance FET [NERFET]
    • H01L29/66462—Unipolar field-effect transistors with an active layer made of a group 13/15 material, e.g. group 13/15 velocity modulation transistor [VMT], group 13/15 negative resistance FET [NERFET] with a heterojunction interface channel or gate, e.g. HFET, HIGFET, SISFET, HJFET, HEMT
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Abstract

The invention relates to a GaN-based high electron mobility transistor and a preparation method thereof, wherein the topmost layer of the transistor is a nitride layer, and nitrogen vacancies are formed in the nitride layer by performing plasma treatment on the surface of the nitride layer, so that heavy doping is formed, and the ohmic contact resistance between a GaN-based substrate and an ohmic metal electrode is reduced. The invention also relates to an ohmic metal electrode and a preparation method thereof, the ohmic metal electrode has a Ti/Al/Ti/Al/Ti/Al/Ni/Au layer structure, the contact area of Ti and Al can be increased, Al plays a role in catalyzing each layer, the reaction of Ni and the barrier layer is more sufficient, and the ohmic contact resistance can be obviously reduced. In addition, the invention also relates to a semiconductor structure and a preparation method thereof.

Description

GaN-based high electron mobility transistor, ohmic metal electrode and preparation method thereof
Technical Field
The invention relates to the field of semiconductor microwave power devices, in particular to a GaN-based high electron mobility transistor, an ohmic metal electrode, a preparation method of the GaN-based high electron mobility transistor and the ohmic metal electrode, a semiconductor structure comprising the GaN-based high electron mobility transistor and the ohmic metal electrode, and a preparation method of the semiconductor structure.
Background
Because the GaN material has the advantages of large forbidden band width, high breakdown electric field, high electron saturation drift velocity, high melting point and the like, the GaN material becomes the hot first choice of the next generation of wireless infrastructure. High Electron Mobility Transistors (HEMTs) based on group III-N heterostructures are considered to be the most promising devices for high power and high frequency applications due to the ability of GaN materials to form heterostructures, the spontaneous and piezoelectric polarization effects of the materials to generate very high two-dimensional electron gas concentrations. However, the ohmic contact technology has become one of the key technologies affecting the performance of GaN-based microwave semiconductor devices, and the large ohmic contact resistance between HEMTs and ohmic metal electrodes causes problems of excessive power loss and reduced device reliability.
Therefore, it is highly desirable to develop structures and methods that can reduce ohmic contact resistance.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a GaN-based high electron mobility transistor and a preparation method thereof.
Another object of the present invention is to provide an ohmic metal electrode and a method for manufacturing the same, wherein the ohmic metal electrode has a Ti/Al/Ni/Au layer structure, which can increase the contact area between Ti and Al, and Al plays a role in catalysis at each layer, so that Ni reacts with a barrier layer more sufficiently, thereby significantly reducing ohmic contact resistance.
It is another object of the present invention to provide a semiconductor structure and a method for fabricating the same.
In order to achieve the above object, the present invention provides the following technical solutions.
A GaN-based high electron mobility transistor, the topmost layer of which is a nitride layer for forming ohmic contact with an ohmic metal electrode, wherein the nitride layer has nitrogen vacancies.
The invention also provides a preparation method of the GaN-based high electron mobility transistor, which comprises the following steps:
and carrying out plasma treatment on the surface of the topmost layer of the GaN-based high electron mobility transistor so as to form nitrogen vacancies inside the topmost layer.
The invention also provides a preparation method of the ohmic metal electrode, which comprises the following steps:
patterning the photoresist by photoetching to form an ohmic metal electrode window;
after patterning, sequentially forming a first Ti layer, a first Al layer, a second Ti layer, a second Al layer, a third Ti layer, a third Al layer, a Ni layer and an Au layer from bottom to top so as to cover the ohmic metal electrode window;
and stripping metal to remove the residual photoresist and the first Ti layer part, the first Al layer part, the second Ti layer part, the second Al layer part, the third Ti layer part, the third Al layer part, the Ni layer part and the Au layer part which are positioned on the upper surface of the photoresist, thereby obtaining the ohmic metal electrode.
The invention also provides an ohmic metal electrode obtained by the preparation method.
The invention also provides a preparation method of the semiconductor structure, which comprises the following steps:
coating photoresist on the upper surface of the topmost layer of the GaN-based high electron mobility transistor and patterning through photoetching to expose partial upper surface of the topmost layer so as to form an ohmic metal electrode window;
after patterning, sequentially forming a first Ti layer, a first Al layer, a second Ti layer, a second Al layer, a third Ti layer, a third Al layer, a Ni layer and an Au layer from bottom to top so as to cover the ohmic metal electrode window;
carrying out metal stripping to remove the residual photoresist and the first Ti layer part, the first Al layer part, the second Ti layer part, the second Al layer part, the third Ti layer part, the third Al layer part, the Ni layer part and the Au layer part which are positioned on the upper surface of the photoresist;
after metal stripping, annealing the obtained structure to form ohmic contact; and
mesa isolation is performed to obtain a semiconductor structure.
The invention also provides a semiconductor structure obtained by the preparation method.
Compared with the prior art, the invention has the beneficial effects that:
1. the invention provides a GaN-based high electron mobility transistor and a preparation method thereof, wherein the topmost layer of the transistor is a nitride layer, and the invention forms nitrogen vacancy in the nitride layer by carrying out plasma treatment on the surface of the nitride layer, thereby forming heavy doping, and further reducing ohmic contact resistance between the GaN-based high electron mobility transistor and an ohmic metal electrode.
2. The invention also provides an ohmic metal electrode and a preparation method thereof, wherein the ohmic metal electrode has a Ti/Al/Ti/Al/Ni/Au layer structure. Compared with the existing Ti/Al/Ni/Au ohmic metal electrode, the ohmic metal electrode has larger contact area of Ti and Al, so that the reaction of Ti and the barrier layer is more sufficient under the more effective catalytic action of Al, and the ohmic contact resistance is obviously reduced.
Drawings
Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. Also, like reference numerals are used to refer to like parts throughout the drawings. In the drawings:
fig. 1 is a schematic structural view of an exemplary GaN-based high electron mobility transistor of the present invention.
Fig. 2 to 4 are schematic structural views obtained at each step in the method for manufacturing an ohmic metal electrode according to the present invention.
Fig. 5 is a partial structural diagram of a semiconductor structure according to the present invention.
Description of the reference numerals
100 is a substrate, 200 is a GaN buffer layer, 300 is a GaN channel layer, 400 is an AlN insertion layer, 500 is an InAlN barrier layer, 600 is a GaN cap layer, 700 is an AlN nucleation layer, 800 is an ohmic metal electrode window, 900 is a first Ti layer, 1000 is a first Al layer, 1100 is a second Ti layer, 1200 is a second Al layer, 1300 is a third Ti layer, 1400 is a third Al layer, 1500 is a Ni layer, and 1600 is an Au layer.
Detailed Description
Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be understood that these descriptions are illustrative only and are not intended to limit the scope of the present disclosure. Moreover, in the following description, descriptions of well-known structures and techniques are omitted so as to not unnecessarily obscure the concepts of the present disclosure.
Various structural schematics according to embodiments of the present disclosure are shown in the figures. The figures are not drawn to scale, wherein certain details are exaggerated and possibly omitted for clarity of presentation. The shapes of various regions, layers, and relative sizes and positional relationships therebetween shown in the drawings are merely exemplary, and deviations may occur in practice due to manufacturing tolerances or technical limitations, and a person skilled in the art may additionally design regions/layers having different shapes, sizes, relative positions, as actually required.
In the context of the present disclosure, when a layer/element is referred to as being "on" another layer/element, it can be directly on the other layer/element or intervening layers/elements may be present. In addition, if a layer/element is "on" another layer/element in one orientation, then that layer/element may be "under" the other layer/element when the orientation is reversed.
Because the existing GaN-based microwave semiconductor device has larger ohmic contact resistance, the performance of the GaN-based microwave semiconductor device is seriously influenced. Accordingly, the present invention provides an improved GaN-based high electron mobility transistor.
The topmost layer of the GaN-based high electron mobility transistor is a nitride layer which is used for forming ohmic contact with an ohmic metal electrode, wherein the nitride layer has nitrogen vacancies.
Because nitrogen vacancies are formed in the nitride layer, and heavy doping is further formed, the ohmic contact resistance between the GaN-based high electron mobility transistor and the ohmic metal electrode is reduced.
The GaN-based hemt of the present invention may be any of the existing GaN-based hemts as long as the uppermost layer is a nitride layer.
Preferably, the nitride layer is a cap layer or a barrier layer, wherein the cap layer is GaN, and the barrier layer is one or a combination of InAlN, AlGaN and AlN.
In some embodiments, as shown in fig. 1, the GaN-based high electron mobility transistor of the present invention comprises: the GaN-based light-emitting diode comprises a substrate 100, a GaN buffer layer 200, a GaN channel layer 300, an AlN insert layer 400, an InAlN barrier layer 500 and a GaN capping layer 600 which are sequentially stacked from bottom to top, wherein the GaN capping layer 600 has nitrogen vacancies. In other embodiments, the GaN-based hemt of the present invention may comprise: the GaN-based light-emitting diode comprises a substrate, a buffer layer, a GaN channel layer, an AlN insert layer and an InAlN barrier layer which are sequentially stacked from bottom to top, wherein the InAlN barrier layer is provided with nitrogen vacancies.
Preferably, in these embodiments, the GaN-based high electron mobility transistor of the present invention further comprises: an AlN nucleation layer 700 is disposed between the substrate 100 and the GaN buffer layer 200.
Preferably, the GaN capping layer 600 is n+-GaN。
Preferably, in these embodiments, the substrate 100 may be a sapphire substrate or a SiC substrate.
Preferably, in these embodiments, the thickness of the GaN buffer layer 200 may be 1-3 μm, such as 1.5-2.5 μm; the thickness of the GaN channel layer 300 may be 200-600nm, such as 300-500 nm; the AlN insert layer 400 may have a thickness of 0.5 to 1.5nm, for example, 0.8 to 1.2 nm; the InAlN barrier layer 500 may have a thickness of 5-15nm, for example 8-12 nm; the thickness of the GaN capping layer 600 may be 4-12nm, for example 6-10 nm; the AlN nucleation layer 700 may have a thickness of 80-160nm, such as 100-140 nm.
The invention also provides a preparation method of the GaN-based high electron mobility transistor, which comprises the step of carrying out plasma treatment on the topmost surface of the GaN-based high electron mobility transistor so as to form nitrogen vacancies inside the topmost layer.
Preferably, the plasma treatment may be argon plasma, SiCl4And plasma or oxygen plasma treatment is carried out, the chemical property of the argon plasma is stable, and the argon plasma does not react with nitrogen after bombardment, so that the influence of external factors is reduced.
Preferably, the pressure of the plasma may be 2 to 4 times atmospheric pressure, preferably 2 times atmospheric pressure. The flow rate of the plasma may be 40 to 85sccm, preferably 40 sccm. The plasma treatment time may be 10 to 15min, preferably 13 min. The RF power for the plasma treatment may be 20 to 50W, preferably 30W. The ICP power for the plasma treatment may be 200 to 280W, preferably 250W.
Preferably, the GaN-based hemt is cleaned and baked before the plasma treatment.
Preferably, the cleaning comprises: and sequentially using acetone, ethanol and deionized water to carry out ultrasonic cleaning, thereby removing dirt and oxides on the surface of the GaN-based high electron mobility transistor.
Preferably, after washing, drying is performed immediately. Preferably, the drying is hot plate drying.
The invention also provides a preparation method of the ohmic metal electrode, and the preparation process is shown in figures 2-4 and specifically comprises the following steps.
Patterning is performed by photolithography using photoresist, thereby forming an ohmic metal electrode window 800, as shown in fig. 2.
In the present invention, a photoresist may be first coated on an upper surface of a topmost layer of the GaN-based hemt, and a portion of the photoresist may be removed by photolithography, thereby forming the ohmic metal electrode window 800. The ohmic metal electrode window 800 may be formed in a suitable shape and size according to the actual requirements of the ohmic metal electrode.
Preferably, the photoresist remaining at the ohmic metal electrode window 800 is removed after patterning and before forming the first Ti layer 900.
Since photoresist may remain at the ohmic metal electrode window 800 during photolithography development, the photoresist that needs to be removed but cannot be removed affects the formation of the ohmic metal electrode and the ohmic contact resistance, and therefore, the residual photoresist needs to be removed before the metal layer is formed.
Preferably, the removal method may be performed by one or a combination of both of the following first and second methods.
The method comprises the following steps: soaking the structure shown in fig. 2 in a heated organic solvent; taking out, and sequentially carrying out ultrasonic treatment on N-methylpyrrolidone, isopropanol and water; and blow-drying with nitrogen. The heating temperature may be 50-70 deg.C. The organic solvent may be N-methylpyrrolidone. The soaking time can be 20-40 min. Preferably, each sonication time may be 3-7 min.
The second method comprises the following steps: the structure shown in fig. 2 is washed with water and dried with nitrogen; and sequentially utilizing hydrochloric acid water solution and water for cleaning, and drying by nitrogen. The soaking time can be 50-70 s. The time for washing with the aqueous hydrochloric acid solution may be 30 to 60 seconds.
In some embodiments, the first method and the second method may be performed first, so as to remove the photoresist remaining at the ohmic metal electrode window 800.
After patterning, a first Ti layer 900, a first Al layer 1000, a second Ti layer 1100, a second Al layer 1200, a third Ti layer 1300, a third Al layer 1400, a Ni layer 1500, and an Au layer 1600 are sequentially formed from bottom to top, so as to cover the ohmic metal electrode window 800, as shown in fig. 3.
In some embodiments, the total thickness of the first Ti layer 900, the second Ti layer 1100, and the third Ti layer 1300 may be 16-26nm, preferably 19-23nm, most preferably 21 nm; the total thickness of the first Al layer 1000, the second Al layer 1200 and the third Al layer 1400 can be 145-155nm, preferably 148-152nm, and most preferably 150 nm; the thickness of the Ni layer 1500 can be 50-60nm, preferably 53-57nm, most preferably 55nm, and the thickness of the Au layer 1600 can be 40-50nm, preferably 43-47nm, most preferably 45 nm. In the present invention, as long as the total thickness of the first Ti layer 900, the second Ti layer 1100, and the third Ti layer 1300 satisfies the above-described condition, the specific thicknesses of each may be arbitrarily combined. Likewise, as long as the total thickness of the first Al layer 1000, the second Al layer 1200, and the third Al layer 1400 satisfies the above condition, the specific thicknesses of each may be arbitrarily combined.
In some embodiments, the total thickness of the first Ti layer 900, the second Ti layer 1100, and the third Ti layer 1300 is 21 nm; the total thickness of the first Al layer 1000, the second Al layer 1200, and the third Al layer 1400 is 150 nm; the thickness of the Ni layer 1500 is 55nm and the thickness of the Au layer 1600 is 45 nm.
In one embodiment, the thickness of the first Ti layer 900 may be 7nm, the thickness of the first Al layer 1000 may be 50nm, the thickness of the second Ti layer 1100 may be 7nm, the thickness of the second Al layer 1200 may be 50nm, the thickness of the third Ti layer 1300 may be 7nm, the thickness of the third Al layer 1400 may be 50nm, the thickness of the Ni layer 1500 may be 55nm, and the thickness of the Au layer 1600 may be 45 nm. Compared with the existing Ti/Al/Ni/Au (thickness: 21nm/150nm/55nm/45nm) ohmic metal electrode, the total amount and proportion of Ti and Al in the ohmic metal electrode are kept unchanged, but the contact area of Ti and Al is larger, so that the reaction of Ti and a barrier layer is more sufficient under the more effective catalytic action of Al, and the ohmic contact resistance is obviously reduced.
Preferably, the first Ti layer 900, the first Al layer 1000, the second Ti layer 1100, the second Al layer 1200, the third Ti layer 1300, the third Al layer 1400, the Ni layer 1500, and the Au layer 1600 are all formed by electron beam evaporation.
And then, carrying out metal stripping to remove the residual photoresist and the first Ti layer 900 part, the first Al layer 1000 part, the second Ti layer 1100 part, the second Al layer 1200 part, the third Ti layer 1300 part, the third Al layer 1400 part, the Ni layer 1500 part and the Au layer 1600 part which are positioned on the upper surface of the photoresist, thereby obtaining the ohmic metal electrode, as shown in FIG. 4.
Preferably, the metal stripping is performed in an organic solvent. Preferably, the organic solvent is ethanol, acetone or a mixture thereof. Preferably, the temperature of the metal stripping can be 60-80 ℃, and the time of the metal stripping can be more than 30 min.
The invention also provides a preparation method of the semiconductor structure, which specifically comprises the following steps.
First, a photoresist is coated on the top surface of the topmost layer of the GaN-based hemt and patterned by photolithography such that a portion of the top surface of the topmost layer is exposed, thereby forming an ohmic metal electrode window 800.
Preferably, before coating the photoresist, performing plasma treatment on the topmost surface of the GaN-based high electron mobility transistor so as to form nitrogen vacancies inside the topmost layer. As described above, the formation of nitrogen vacancies causes the formation of heavy doping inside the topmost layer, thereby reducing the ohmic contact resistance between the GaN-based high electron mobility transistor and the ohmic metal electrode.
After patterning, a first Ti layer 900, a first Al layer 1000, a second Ti layer 1100, a second Al layer 1200, a third Ti layer 1300, a third Al layer 1400, a Ni layer 1500, and an Au layer 1600 are sequentially formed from bottom to top, so as to cover the ohmic metal electrode window 800.
Then, metal stripping is performed to remove the remaining photoresist and the first Ti layer 900 portion, the first Al layer 1000 portion, the second Ti layer 1100 portion, the second Al layer 1200 portion, the third Ti layer 1300 portion, the third Al layer 1400 portion, the Ni layer 1500 portion, and the Au layer 1600 portion on the upper surface of the photoresist.
After metal stripping, the resulting structure is annealed to form ohmic contacts.
Preferably, the annealing temperature is 750 ℃ to 850 ℃, preferably 800 ℃ to 850 ℃. Preferably, the annealing time is 30-70s, preferably 40-60 s.
Finally, mesa isolation is formed, thereby obtaining the semiconductor structure.
Preferably, the mesa isolation may be formed by photolithography and etching. The etching may be dry etching or the like.
The invention will be further illustrated with reference to specific embodiments and the accompanying drawings.
Example 1
First, a GaN-based high electron mobility transistor sample is provided, which includes: the substrate 100, the AlN nucleation layer 700, the GaN buffer layer 200, the GaN channel layer 300, the AlN insert layer 400, the InAlN barrier layer 500 and the GaN cap layer 600 are sequentially stacked from bottom to top.
And then, ultrasonically cleaning the sample by using acetone, ethanol and deionized water in sequence to remove dirt and oxides on the surface of the sample.
After the cleaning, hot plate drying is immediately carried out.
Then, argon plasma pressure, flow rate, time, RF power, and ICP power are set, and argon plasma treatment is performed on the surface of the GaN cap layer 600, thereby forming nitrogen vacancies inside the GaN cap layer 600.
Thereafter, patterning is performed by photolithography using a photoresist, thereby forming an ohmic metal electrode window 800, and the resultant structure is shown in fig. 2.
Next, the structure shown in fig. 2 is washed with deionized water, dried with nitrogen, and examined under a microscope for the alignment condition, the photoresist morphology, whether there is photoresist residue, and repeated defects. A mixed solution of hydrochloric acid (the concentration is 12mol/L) and water is prepared in a ratio of 1:3, and the sample is cleaned for 40s, washed by deionized water and dried by nitrogen.
Then, EVA450 electron beam evaporation of Ti/Al/Ti/Al/Ni/Au (7/50/7/50/7/50/55/45nm) as ohmic metal electrode, the resulting structure is shown in FIG. 3.
Then soaking in an acetone box at 70 deg.C for more than 30min, performing ultrasonic treatment in the acetone box for 5min, performing ultrasonic treatment in an ethanol box for 5min, rinsing with deionized water, and drying with nitrogen. The metal stripping was carried out for 30min, and the resulting structure is shown in fig. 4.
Next, the structure shown in fig. 4 was placed in an annealing furnace and annealed rapidly at 820 ℃ for 50 seconds in a nitrogen atmosphere to form an ohmic contact.
Finally, the active region of the device is isolated by photolithography and etching to form mesa isolation, and the resulting structure is shown in fig. 5.
The ohmic contact resistance of the semiconductor structure obtained in example 1 was measured to be 0.37 Ω · mm.
Example 2
A semiconductor structure was fabricated as in example 1, except that no argon plasma treatment was performed.
The ohmic contact resistance of the semiconductor structure obtained in example 2 was measured to be 0.56 Ω · mm.
Comparative example 1
A semiconductor structure was fabricated as in example 1, except that argon plasma treatment was not performed, and EVA450 electron beam evaporation of Ti/Al/Ni/Au (21/150/55/45nm) as an ohmic metal electrode was performed.
The ohmic contact resistance of the semiconductor structure prepared in comparative example 1 was measured to be 0.72 Ω · mm.
The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope of the present invention are included in the scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the appended claims.

Claims (13)

1. A GaN-based HEMT, wherein the topmost layer is a nitride layer for forming an ohmic contact with an ohmic metal electrode, wherein the nitride layer has nitrogen vacancies.
2. The GaN-based hemt of claim 1, wherein said nitride layer is a cap layer or a barrier layer, wherein said cap layer is GaN and said barrier layer is a combination of one or more of InAlN, AlGaN and AlN.
3. The method of fabricating the GaN-based high electron mobility transistor of any of claims 1-2, comprising:
and carrying out plasma treatment on the surface of the topmost layer of the GaN-based high electron mobility transistor so as to form nitrogen vacancies inside the topmost layer.
4. A production method according to claim 3, characterized in that the plasma treatment is an argon plasma treatment.
5. A manufacturing method according to claim 3 or 4, characterized in that the GaN-based HEMT is cleaned and baked before the plasma treatment.
6. A method for preparing an ohmic metal electrode, comprising:
patterning the photoresist by photoetching to form an ohmic metal electrode window;
after patterning, sequentially forming a first Ti layer, a first Al layer, a second Ti layer, a second Al layer, a third Ti layer, a third Al layer, a Ni layer and an Au layer from bottom to top so as to cover the ohmic metal electrode window; and
and stripping metal to remove the residual photoresist and the first Ti layer part, the first Al layer part, the second Ti layer part, the second Al layer part, the third Ti layer part, the third Al layer part, the Ni layer part and the Au layer part which are positioned on the upper surface of the photoresist, thereby obtaining the ohmic metal electrode.
7. The method of claim 6, wherein the first Ti layer, the first Al layer, the second Ti layer, the second Al layer, the third Ti layer, the third Al layer, the Ni layer, and the Au layer are all formed by electron beam evaporation.
8. The production method according to claim 6 or 7, characterized by further comprising:
and after patterning and before forming the first Ti layer, removing the residual photoresist at the window of the ohmic metal electrode.
9. An ohmic metal electrode, characterized in that it is obtained by the production method according to any one of claims 6 to 8.
10. A method of fabricating a semiconductor structure, comprising:
coating photoresist on the upper surface of the topmost layer of the GaN-based high electron mobility transistor and patterning through photoetching to expose partial upper surface of the topmost layer so as to form an ohmic metal electrode window;
after patterning, sequentially forming a first Ti layer, a first Al layer, a second Ti layer, a second Al layer, a third Ti layer, a third Al layer, a Ni layer and an Au layer from bottom to top so as to cover the ohmic metal electrode window;
carrying out metal stripping to remove the residual photoresist and the first Ti layer part, the first Al layer part, the second Ti layer part, the second Al layer part, the third Ti layer part, the third Al layer part, the Ni layer part and the Au layer part which are positioned on the upper surface of the photoresist;
after metal stripping, annealing the obtained structure to form ohmic contact; and
mesa isolation is formed, thereby obtaining a semiconductor structure.
11. The method of claim 10, further comprising:
and before coating photoresist, carrying out plasma treatment on the topmost surface of the GaN-based high electron mobility transistor so as to form nitrogen vacancies inside the topmost layer.
12. The method of claim 10 or 11, wherein the annealing temperature is 750 ℃ to 850 ℃; the annealing time is 30-70 s.
13. A semiconductor structure obtained by the production method according to any one of claims 10 to 12.
CN202210230849.2A 2022-03-09 2022-03-09 GaN-based high electron mobility transistor, ohmic metal electrode and preparation method thereof Pending CN114784096A (en)

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Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116544275A (en) * 2023-04-18 2023-08-04 山东大学 GaN HEMTs and method for reducing ohmic contact resistance of device

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN116544275A (en) * 2023-04-18 2023-08-04 山东大学 GaN HEMTs and method for reducing ohmic contact resistance of device
CN116544275B (en) * 2023-04-18 2024-06-11 山东大学 GaN HEMTs and method for reducing ohmic contact resistance of device

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