GaN-based HEMT (High Electron Mobility Transistor) epitaxial structure with novel GaN high-resistance layer design

Abstract

The invention relates to a GaN-based HEMT epitaxial structure with a novel GaN high-resistance layer design, and belongs to the technical field of semiconductor devices, the GaN-based HEMT epitaxial structure comprises a substrate, a buffer layer, a high-resistance layer and a channel layer, the high-resistance layer is positioned on the buffer layer, the high-resistance layer comprises a first functional sub-layer, a second functional sub-layer and a third functional sub-layer, the channel layer is positioned on the high-resistance layer, and the channel layer is positioned on the first functional sub-layer. The barrier layer is located on the high-resistance layer, and the cap layer is located on the barrier layer. After the structure is adopted, the GaN-based HEMT epitaxial structure has the following advantages that the design of the high-resistance layer effectively improves the voltage resistance performance and the longitudinal current blocking capability of the GaN-based HEMT epitaxial structure, so that the GaN-based HEMT epitaxial structure is suitable for a higher-voltage application scene, meanwhile, the on resistance of a device is relatively reduced, and the current transverse transmission performance of the device is improved.

Description

Technical Field

[0001] The invention relates to the technical field of semiconductor devices, and in particular to a GaN-based HEMT epitaxial structure with a novel GaN high-resistance layer design. Background Art

[0002] GaN-based high electron mobility transistors (HEMTs) are widely used in power electronics, high-frequency microwaves and other fields due to their high electron mobility, low on-resistance and good blocking capability.

[0003] For example, the existing patent, application number 202011174655.2, is a HEMT device, a HEMT epitaxial structure based on a GaN substrate, and a manufacturing method. The HEMT epitaxial structure based on a GaN substrate includes an interface treatment layer, a barrier layer, an isolation layer, a channel layer, and a contact layer sequentially formed on a semi-insulating GaN substrate with N-face polarity.

[0004] However, in practical applications, the voltage resistance and current blocking capability of the device cannot be improved, and the voltage resistance and current blocking capability of GaN-based HEMT devices still face certain challenges. Summary of the invention

[0005] The present invention aims to solve the above technical problems and provides a GaN-based HEMT epitaxial structure with a novel GaN high-resistance layer design.

[0006] In order to solve the above technical problems, the technical solution provided by the present invention is: A GaN-based HEMT epitaxial structure with a new GaN high-resistance layer design, including substrate; a buffer layer, located on the substrate; A high resistance layer is located on the buffer layer, the high resistance layer includes a first functional sublayer, a second functional sublayer and a third functional sublayer, the first functional sublayer is an electron blocking layer and is a wide bandgap material with a bandgap width higher than that of the buffer layer, and the structure of the first functional sublayer is an AlxGa1-xN / AlyGa1-yN superlattice structure; the second functional sublayer is a vertical insertion compensation layer and is a periodic vertical insertion compensation doping, and the doping source contains C or Fe compounds; the third functional sublayer is a carrier neutralization layer and is a gradient-increasing doping design; A channel layer, located on the high resistance layer; The barrier layer is located above the high resistance layer; Cap layer, located above the barrier layer.

[0007] Preferably, the AlxGa1-xN is designed as a barrier layer, wherein 30%≤x≤100%.

[0008] Preferably, the AlyGa1-yN is designed as a potential well layer, wherein 0≤y≤50%.

[0009] Preferably, the superlattice structure is composed of periodically alternating wide and narrow bandgap well barrier layers.

[0010] Preferably, the cap layer is a non-artificially doped GaN layer or a SiN layer or an artificially doped P-type GaN layer.

[0011] Preferably, the third functional sublayer forms a maximum doping step with the channel layer at a surface far away from the substrate.

[0012] Preferably, the barrier layer has a higher bandgap than the channel layer, forming a heterojunction two-dimensional electron gas.

[0013] After adopting the above structure, the present invention has the following advantages: The high-resistance layer design of the present invention effectively improves the voltage resistance and longitudinal current blocking capability of the GaN-based HEMT epitaxial structure, making it suitable for higher voltage application scenarios, while relatively reducing the on-resistance of the device and improving the lateral current transmission performance of the device.

[0014] The above summary is for illustrative purposes only and is not intended to be limiting in any way. In addition to the illustrative aspects, embodiments and features described above, further aspects, embodiments and features of the present invention will be readily apparent by reference to the accompanying drawings and the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or technical descriptions will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 It is the electron density diagram of the lateral transport electron channel of the present invention. DETAILED DESCRIPTION

[0017] Specific embodiments of the present invention will now be mentioned in detail. Although the present invention is described in conjunction with these specific embodiments, it should be appreciated that it is not intended to limit the present invention to these specific embodiments. On the contrary, these embodiments are intended to cover substitutions, changes or equivalent embodiments that may be included in the spirit and scope of the invention defined by the claims. In the following description, a large number of specific details are set forth in order to provide a comprehensive understanding of the present invention. The present invention can be implemented without some or all of these specific details. In other cases, in order not to make the present invention unnecessarily obscure, well-known process operations are not described in detail.

[0018] When used in conjunction with "including," "methods comprising," or similar language in this specification and the appended claims, the singular forms "a," "an," and "the" include plural references unless the context clearly dictates otherwise. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[0019] The present invention is further described in detail below in conjunction with the full text.

[0020] Combined with Figure 1 , a new GaN-based HEMT epitaxial structure with a GaN high-resistance layer design, including substrate; a buffer layer, located on the substrate; High resistance layer, located above the buffer layer, The high resistance layer includes a first functional sublayer, a second functional sublayer and a third functional sublayer, The first functional sublayer electron blocking layer is designed to be a wide bandgap material with a higher bandgap than the buffer layer, with high thermal stability and good electrical properties, which can provide ideal blocking properties. Its structure is designed as an AlxGa1-xN / AlyGa1-yN superlattice structure, which further improves the blocking properties and enhances the epitaxial withstand voltage performance, where 30%≤x≤100%, 0≤y≤50%; the AlxGa1-xN layer is designed as a barrier layer, and the AlyGa1-yN layer is designed as a well layer; the superlattice structure is composed of periodically alternating wide and narrow bandgap well barrier layers, and excellent electron blocking performance is achieved by modulating the layer thickness and component ratio.

[0021] The second functional sublayer is a vertical insertion compensation layer, and the second functional sublayer is designed as a periodic vertical insertion compensation doping, and the doping source contains C or Fe-containing compounds, not limited to C2H4, CP2Fe, as shown in Table 1; the vertically inserted high-doping compensation layer can annihilate the unintentionally introduced different energy level carriers in the gallium nitride material, and the low-doping compensation layer is usually used as a relaxation buffer for the vertically inserted high compensation layer. Low and high are relative concepts.

[0022] Table 1

[0023] The third functional sublayer is a carrier neutralization layer with a gradient doping design, forming a maximum doping step with the channel layer on the surface away from the substrate, as shown in Table 2; precise doping control in the high resistance layer can optimize the device's conductive performance and blocking characteristics. Gradient doping technology is used to gradually increase the doping concentration to achieve good rectification characteristics. The longitudinal current is limited, the lateral on-resistance is reduced, and the lateral current conduction characteristics of the device are improved.

[0024] Table 2

[0025] The channel layer is located on the high resistance layer and has different doping characteristics from the semiconductor material of the high resistance layer; The barrier layer is located on the high resistance layer; it has a higher bandgap than the channel layer, forming a heterojunction two-dimensional electron gas; The cap layer is located on the barrier layer; the cap layer is a non-artificially doped GaN layer or SiN layer or an artificially doped P-type GaN layer; it can be divided into a depletion type or an enhancement type device according to the characteristic requirements.

[0026] The first functional sublayer, the second functional sublayer and the third functional sublayer of the high-resistance layer effectively improve the voltage resistance and longitudinal current blocking capability of the GaN-based HEMT epitaxial structure, making it suitable for higher voltage application scenarios. At the same time, it relatively reduces the on-resistance of the device and improves the lateral current transmission performance of the device.

[0027] When the present invention is specifically implemented, Figure 1 As shown in the above invention, after the MOCVD equipment optimization experiment process, the epitaxial layer cross-section thickness-electron concentration curve was tested using CV equipment. The highest point of carrier concentration was 1E+19, which was also the position of the two-dimensional electron gas; when the epitaxial layer depth was about 0.7um, the carrier concentration (after intrinsic GaN compensation doping) was close to 1E+13; the electron transport layer (1E+19) / optimized high resistance layer (1E+13)>1E+6, which meets the high resistance characteristics without over-compensation. Specifically, when the gate is pressurized, the cross-sectional carrier distribution, the electron density of the lateral transmission electron channel is 1E+6 to 1E+7 times that of the high resistance layer, with good confinement characteristics, showing excellent lateral migration and longitudinal blocking characteristics.

[0028] Embodiment 1:

[0029] A GaN-based HEMT epitaxial structure with a new GaN high-resistance layer design, including substrate; a buffer layer, located on the substrate; A high resistance layer is located on the buffer layer. The high resistance layer includes a first functional sublayer, a second functional sublayer and a third functional sublayer. The first functional sublayer is an electron blocking layer and is a wide bandgap material with a bandgap width higher than that of the buffer layer. The structure of the first functional sublayer is an AlxGa1-xN / AlyGa1-yN superlattice structure. The superlattice structure is composed of periodically alternating wide and narrow bandgap well barrier layers, wherein AlxGa1-xN is designed as a barrier layer, wherein x is 31%, and AlyGa1-yN is designed as a well layer, wherein y is 2%; The second functional sublayer is a vertically inserted compensation layer and is a periodic vertically inserted compensation doping. The doping source contains C compounds. The vertically inserted high-doped compensation layer can annihilate the unartificially introduced carriers of different energy levels in the gallium nitride material. The low-doped compensation layer usually serves as a relaxation buffer for the vertically inserted high compensation layer; the third functional sublayer is a carrier neutralization layer and is designed with a gradient-increasing doping; the third functional sublayer forms a maximum doping step with the channel layer on the surface away from the substrate.

[0030] A channel layer, located on the high resistance layer; The barrier layer is located on the high resistance layer and has a higher bandgap width than the channel layer, forming a heterojunction two-dimensional electron gas.

[0031] The cap layer is located on the barrier layer, and the cap layer is a non-artificially doped GaN layer.

[0032] Embodiment 2:

[0033] A GaN-based HEMT epitaxial structure with a new GaN high-resistance layer design, including substrate; a buffer layer, located on the substrate; The high resistance layer is located on the buffer layer, and the high resistance layer includes a first functional sublayer, a second functional sublayer and a third functional sublayer. The first functional sublayer is an electron blocking layer and is a wide bandgap material with a bandgap width higher than that of the buffer layer. The structure of the first functional sublayer is an AlxGa1-xN / AlyGa1-yN superlattice structure; the superlattice structure is composed of periodically alternating wide and narrow bandgap well barrier layers, wherein AlxGa1-xN is designed as a barrier layer, wherein x is 98%, and AlyGa1-yN is designed as a well layer, wherein y is 46%.

[0034] The second functional sublayer is a vertically inserted compensation layer and is a periodic vertically inserted compensation doping. The doping source contains Fe compounds. The vertically inserted high-doped compensation layer can annihilate the unartificially introduced carriers of different energy levels in the gallium nitride material. The low-doped compensation layer usually serves as a relaxation buffer for the vertically inserted high compensation layer. The third functional sublayer is a carrier neutralization layer and is designed with a gradient-increasing doping; the third functional sublayer forms a maximum doping step with the channel layer on the surface away from the substrate.

[0035] A channel layer, located on the high resistance layer; The barrier layer is located on the high resistance layer and has a higher bandgap width than the channel layer, forming a heterojunction two-dimensional electron gas.

[0036] The cap layer is located on the barrier layer, and the cap layer is a SiN layer.

[0037] Embodiment three:

[0038] A GaN-based HEMT epitaxial structure with a new GaN high-resistance layer design, including substrate; a buffer layer, located on the substrate; The high resistance layer is located on the buffer layer, and the high resistance layer includes a first functional sublayer, a second functional sublayer and a third functional sublayer. The first functional sublayer is an electron blocking layer and is a wide bandgap material with a bandgap width higher than that of the buffer layer. The structure of the first functional sublayer is an AlxGa1-xN / AlyGa1-yN superlattice structure; the superlattice structure is composed of periodically alternating wide and narrow bandgap well barrier layers, wherein AlxGa1-xN is designed as a barrier layer, wherein x is 45%, and AlyGa1-yN is designed as a well layer, wherein y is 25%.

[0039] The second functional sublayer is a vertically inserted compensation layer and is a periodic vertically inserted compensation doping. The doping source contains C compounds. The vertically inserted high-doped compensation layer can annihilate the unartificially introduced carriers of different energy levels in the gallium nitride material. The low-doped compensation layer usually serves as a relaxation buffer for the vertically inserted high compensation layer; the third functional sublayer is a carrier neutralization layer and is designed with a gradient-increasing doping; the third functional sublayer forms a maximum doping step with the channel layer on the surface away from the substrate.

[0040] A channel layer, located on the high resistance layer; The barrier layer is located on the high resistance layer and has a higher bandgap width than the channel layer, forming a heterojunction two-dimensional electron gas.

[0041] The cap layer is located on the barrier layer, and the cap layer is an artificially doped P-type GaN layer.

[0042] Embodiment 4:

[0043] A GaN-based HEMT epitaxial structure with a new GaN high-resistance layer design, including substrate; a buffer layer, located on the substrate; The high resistance layer is located on the buffer layer, and the high resistance layer includes a first functional sublayer, a second functional sublayer and a third functional sublayer. The first functional sublayer is an electron blocking layer and is a wide bandgap material with a bandgap width higher than that of the buffer layer. The structure of the first functional sublayer is an AlxGa1-xN / AlyGa1-yN superlattice structure; the superlattice structure is composed of periodically alternating wide and narrow bandgap well barrier layers, wherein AlxGa1-xN is designed as a barrier layer, wherein x is 85%, and AlyGa1-yN is designed as a well layer, wherein y is 35.

[0044] The second functional sublayer is a vertically inserted compensation layer and is a periodic vertically inserted compensation doping. The doping source contains C compounds. The vertically inserted high-doped compensation layer can annihilate the unartificially introduced carriers of different energy levels in the gallium nitride material. The low-doped compensation layer usually serves as a relaxation buffer for the vertically inserted high compensation layer; the third functional sublayer is a carrier neutralization layer and is designed with a gradient-increasing doping; the third functional sublayer forms a maximum doping step with the channel layer on the surface away from the substrate.

[0045] A channel layer, located on the high resistance layer; The barrier layer is located on the high resistance layer and has a higher bandgap width than the channel layer, forming a heterojunction two-dimensional electron gas.

[0046] The cap layer is located on the barrier layer, and the cap layer is a non-artificially doped GaN layer.

[0047] Embodiment five:

[0048] A GaN-based HEMT epitaxial structure with a new GaN high-resistance layer design, including substrate; a buffer layer, located on the substrate; The high resistance layer is located on the buffer layer, and the high resistance layer includes a first functional sublayer, a second functional sublayer and a third functional sublayer. The first functional sublayer is an electron blocking layer and is a wide bandgap material with a bandgap width higher than that of the buffer layer. The structure of the first functional sublayer is an AlxGa1-xN / AlyGa1-yN superlattice structure; the superlattice structure is composed of periodically alternating wide and narrow bandgap well barrier layers, wherein AlxGa1-xN is designed as a barrier layer, wherein x is 15%, and AlyGa1-yN is designed as a well layer, wherein y is 12%.

[0049] The second functional sublayer is a vertically inserted compensation layer and is a periodic vertically inserted compensation doping. The doping source contains C compounds. The vertically inserted high-doped compensation layer can annihilate the unartificially introduced carriers of different energy levels in the gallium nitride material. The low-doped compensation layer usually serves as a relaxation buffer for the vertically inserted high compensation layer; the third functional sublayer is a carrier neutralization layer and is designed with a gradient-increasing doping; the third functional sublayer forms a maximum doping step with the channel layer on the surface away from the substrate.

[0050] A channel layer, located on the high resistance layer; The barrier layer is located on the high resistance layer and has a higher bandgap width than the channel layer, forming a heterojunction two-dimensional electron gas.

[0051] The cap layer is located on the barrier layer, and the cap layer is an artificially doped P-type GaN layer.

[0052] Embodiment six:

[0053] A GaN-based HEMT epitaxial structure with a new GaN high-resistance layer design, including substrate; a buffer layer, located on the substrate; The high resistance layer is located on the buffer layer, and the high resistance layer includes a first functional sublayer, a second functional sublayer and a third functional sublayer. The first functional sublayer is an electron blocking layer and is a wide bandgap material with a bandgap width higher than that of the buffer layer. The structure of the first functional sublayer is an AlxGa1-xN / AlyGa1-yN superlattice structure; the superlattice structure is composed of periodically alternating wide and narrow bandgap well barrier layers, wherein AlxGa1-xN is designed as a barrier layer, wherein x is 67%, and AlyGa1-yN is designed as a well layer, wherein y is 12%.

[0054] The second functional sublayer is a vertically inserted compensation layer and is a periodic vertically inserted compensation doping. The doping source contains Fe compounds. The vertically inserted high-doped compensation layer can annihilate the unartificially introduced carriers of different energy levels in the gallium nitride material. The low-doped compensation layer usually serves as a relaxation buffer for the vertically inserted high compensation layer; the third functional sublayer is a carrier neutralization layer and is designed with a gradient-increasing doping; the third functional sublayer forms a maximum doping step with the channel layer on the surface away from the substrate.

[0055] A channel layer, located on the high resistance layer; The barrier layer is located on the high resistance layer and has a higher bandgap width than the channel layer, forming a heterojunction two-dimensional electron gas.

[0056] The cap layer is located on the barrier layer, and the cap layer is a SiN layer.

[0057] Embodiment seven:

[0058] A GaN-based HEMT epitaxial structure with a new GaN high-resistance layer design, including substrate; a buffer layer, located on the substrate; The high resistance layer is located on the buffer layer, and the high resistance layer includes a first functional sublayer, a second functional sublayer and a third functional sublayer. The first functional sublayer is an electron blocking layer and is a wide bandgap material with a bandgap width higher than that of the buffer layer. The structure of the first functional sublayer is an AlxGa1-xN / AlyGa1-yN superlattice structure; the superlattice structure is composed of periodically alternating wide and narrow bandgap well barrier layers, wherein AlxGa1-xN is designed as a barrier layer, wherein x is 15%, and AlyGa1-yN is designed as a well layer, wherein y is 45%.

[0059] The second functional sublayer is a vertically inserted compensation layer and is a periodic vertically inserted compensation doping. The doping source contains Fe compounds. The vertically inserted high-doped compensation layer can annihilate the unartificially introduced carriers of different energy levels in the gallium nitride material. The low-doped compensation layer usually serves as a relaxation buffer for the vertically inserted high compensation layer; the third functional sublayer is a carrier neutralization layer and is designed with a gradient-increasing doping; the third functional sublayer forms a maximum doping step with the channel layer on the surface away from the substrate.

[0060] A channel layer, located on the high resistance layer; The barrier layer is located on the high resistance layer and has a higher bandgap width than the channel layer, forming a heterojunction two-dimensional electron gas.

[0061] The cap layer is located on the barrier layer, and the cap layer is a non-artificially doped GaN layer.

[0062] Embodiment eight:

[0063] A GaN-based HEMT epitaxial structure with a new GaN high-resistance layer design, including substrate; a buffer layer, located on the substrate; The high resistance layer is located on the buffer layer, and the high resistance layer includes a first functional sublayer, a second functional sublayer and a third functional sublayer. The first functional sublayer is an electron blocking layer and is a wide bandgap material with a bandgap width higher than that of the buffer layer. The structure of the first functional sublayer is an AlxGa1-xN / AlyGa1-yN superlattice structure; the superlattice structure is composed of periodically alternating wide and narrow bandgap well barrier layers, wherein AlxGa1-xN is designed as a barrier layer, wherein x is 65%, and AlyGa1-yN is designed as a well layer, wherein y is 23%.

[0064] The second functional sublayer is a vertically inserted compensation layer and is a periodic vertically inserted compensation doping. The doping source contains C compounds. The vertically inserted high-doped compensation layer can annihilate the unartificially introduced carriers of different energy levels in the gallium nitride material. The low-doped compensation layer usually serves as a relaxation buffer for the vertically inserted high compensation layer; the third functional sublayer is a carrier neutralization layer and is designed with a gradient-increasing doping; the third functional sublayer forms a maximum doping step with the channel layer on the surface away from the substrate.

[0065] A channel layer, located on the high resistance layer; The barrier layer is located on the high resistance layer and has a higher bandgap width than the channel layer, forming a heterojunction two-dimensional electron gas.

[0066] The cap layer is located on the barrier layer, and the cap layer is a SiN layer.

[0067] The present invention and its embodiments are described above, and such description is not restrictive. What is shown in the full text is only one of the embodiments of the present invention, and the actual structure is not limited thereto. In short, if ordinary technicians in the field are inspired by it, without departing from the purpose of the invention, they can design a structure and embodiment similar to the technical solution without creativity, which should belong to the protection scope of the present invention.

Claims

1. A GaN-based HEMT epitaxial structure with a novel GaN high-resistance layer design, characterized in that: include substrate; a buffer layer, located on the substrate; A high resistance layer is located on the buffer layer, the high resistance layer includes a first functional sublayer, a second functional sublayer and a third functional sublayer, the first functional sublayer is an electron blocking layer and is a wide bandgap material with a bandgap width higher than that of the buffer layer, and the structure of the first functional sublayer is an AlxGa1-xN / AlyGa1-yN superlattice structure; the second functional sublayer is a vertical insertion compensation layer and is a periodic vertical insertion compensation doping, and the doping source contains C or Fe compounds; the third functional sublayer is a carrier neutralization layer and is a gradient-increasing doping design; A channel layer, located on the high resistance layer; The barrier layer is located above the high resistance layer; Cap layer, located above the barrier layer.

2. According to claim 1, a GaN-based HEMT epitaxial structure with a novel GaN high-resistance layer design is characterized by: The AlxGa1-xN is designed as a barrier layer, wherein 30%≤x≤100%.

3. According to claim 2, a GaN-based HEMT epitaxial structure with a novel GaN high-resistance layer design is characterized in that: The AlyGa1-yN is designed as a potential well layer, wherein 0≤y≤50%.

4. According to claim 3, a GaN-based HEMT epitaxial structure with a novel GaN high-resistance layer design is characterized in that: The super lattice structure is composed of periodically alternating wide and narrow bandgap well barrier layers.

5. The GaN-based HEMT epitaxial structure according to claim 1, characterized in that: The cap layer is a non-artificially doped GaN layer or a SiN layer or an artificially doped P-type GaN layer.

6. The GaN-based HEMT epitaxial structure according to claim 1, characterized in that: The third functional sublayer forms a maximum doping step with the channel layer at a surface far away from the substrate.

7. The GaN-based HEMT epitaxial structure according to claim 1, characterized in that: The barrier layer has a higher bandgap than the channel layer, forming a heterojunction two-dimensional electron gas.

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