Symmetrical GaN-based HEMT structure and preparation method thereof

Abstract

The invention discloses a symmetrical gallium nitride (GaN)-based high electron mobility transistor (HEMT) structure and a preparation method thereof. The HEMT structure comprises a GaN layer, a mask layer, a GaN three-dimensional triangular island, an Al < x > Ga < 1-x > N layer, an insulating dielectric layer and functional electrodes, wherein the upward crystal face of the GaN layer is a non-polar face. The GaN island of a three-dimensional structure is obtained by utilizing selective area epitaxy and combining lateral epitaxy, the GaN island naturally forms a bilaterally symmetrical structure due to the crystal attribute, HEMT prepared in pairs based on the characteristic has the consistency of an atomic level, bilaterally symmetrical semi-polar surface AlGaN / GaN heterojunctions can generate two-dimensional electron gas (2DEG) of which the concentration is convenient to control, and the HEMT has the advantages that the HEMT is simple in structure and high in efficiency. The paired GaN-based HEMT with high quality, high performance and high consistency is realized, and the GaN-based HEMT can be applied to a mirror current source circuit, a differential amplification circuit and the like, and has better consistency and stability compared with a traditional device.

Description

Technical Field

[0001] The invention relates to a symmetrical GaN-based HEMT structure and a preparation method thereof, and belongs to the fields of semiconductor epitaxial growth, GaN-based HEMT, etc. Background Art

[0002] GaN-based HEMTs are becoming increasingly important in modern electronic devices. As a wide bandgap semiconductor material, GaN's unique physical properties give GaN-based HEMTs significant advantages in many applications. On the one hand, GaN's wide bandgap (about 3.4eV) enables it to withstand higher voltages than traditional silicon materials (about 1.1eV). This property enables GaN-based HEMTs to operate stably under high voltage and high power density conditions, making them particularly suitable for power electronics and radio frequency (RF) applications. For example, in power converters and electric vehicle charging systems, GaN-based HEMTs can provide higher switching frequencies and efficiencies, significantly improving system performance and energy utilization. On the other hand, GaN has excellent electron mobility and a high saturation electron velocity, which enables GaN-based HEMTs to achieve high-performance operation at high frequencies. This feature is particularly suitable for high-speed RF communication systems and radar equipment, providing higher frequency response and greater bandwidth. Compared with silicon-based HEMTs, GaN-based HEMTs can better handle high-frequency signals, reduce signal distortion, and improve the overall performance of the system. In addition, the high thermal conductivity of GaN materials enables GaN-based HEMTs to effectively manage heat and reduce the impact of overheating on device performance. High thermal conductivity helps improve device reliability and lifespan and reduce the complexity and cost of heat dissipation systems.

[0003] In general, GaN-based HEMTs have shown significant advantages in high voltage, high power and high frequency applications due to their wide bandgap, high electron mobility and excellent thermal properties. With the advancement of technology and the improvement of manufacturing processes, GaN-based HEMTs are expected to be widely used in more fields and promote the development and innovation of electronic technology. Summary of the invention

[0004] Since the traditional polar surface heterojunction interface of GaN-based semiconductors is perpendicular to its polar axis, the generated 2DEG concentration is relatively large and difficult to control. The present invention provides a semi-polar surface AlGaN / GaN heterojunction structure formed by lattice symmetry, in which the angle between the interface and the polar axis is an acute angle, and the generated 2DEG concentration depends on the angle between the heterojunction interface and the polar axis, which is smaller and easier to control than the traditional polar structure. In the present invention, when Al x Ga 1-xWhen the thickness of the N-layer 104 is greater than 20 nm, the positions of the A electrode 106 and the common C electrode 108 are etched so that the above electrodes are in contact with the GaN islands, thereby generating sufficient current. At the same time, the size of the micropore diameter is specified to be the same as the size of the circumscribed circle diameter of the N-type GaN three-dimensional triangular island 103 in the plane, improving the crystal quality. The GaN three-dimensional triangular island structure is selected to fully release the stress of the epitaxial material while avoiding the negative impact of the etching operation on the crystal quality and weakening the influence of defects and polarization on the carriers. At the same time, the present invention uses selective area epitaxy combined with lateral epitaxy to obtain three-dimensional GaN islands. Due to its crystal properties, a left-right symmetric structure with high consistency is naturally formed, and a HEMT with atomic-level consistency can be prepared, thereby improving its consistency and stability in circuits such as mirror current sources and differential amplifiers, and having broad application prospects.

[0005] To achieve the above object, the present invention adopts the following technical solutions:

[0006] On the one hand, the present invention provides a symmetric GaN-based HEMT structure, characterized in that: the structure includes a GaN layer 101 with a non-polar surface as the upward crystal plane, a mask layer 102 containing a micropore array, a GaN three-dimensional triangular island 103, and an Al with an Al composition of 0.1 < x < 0.4 x Ga 1-x N layer 104, an insulating dielectric layer 105, an A electrode 106 below the GaN three-dimensional triangular island 103, a B electrode 107 on the insulating dielectric layer 105, and a common C electrode 108 on the top of the GaN three-dimensional triangular island 103; wherein, the bottom of the GaN three-dimensional triangular island 103 is epitaxially grown upward from the micropores of the mask layer 102, and except for the bottom, it includes two left-right symmetric triangular inclined planes and a triangular side perpendicular to the bottom surface; moreover, the Al x Ga 1-x N layer 104, the insulating dielectric layer 105, the A electrode 106 and the B electrode 107 are both symmetrically arranged on the inclined planes of the GaN three-dimensional triangular island 103, and the parameters of the same structure are exactly the same; the Al on the left x Ga 1-x N layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 constitute the HEMT structure L; the Al on the right x Ga 1-x N layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 constitute the HEMT structure R.

[0007] Preferably, the mask layer 102 containing the micropore array is a 5-50 nm thick dielectric film plated on the non-polar surface GaN layer 101, wherein the dielectric film is one of SiO2, SiN or hBN, and the micropore array is etched from top to bottom by process technology, and the underlying non-polar surface GaN layer 101 is exposed in the micropores; the diameter of the micropores is between 0.5 and 5 μm, and they are arranged in a close-packed form with the centers of the micropores, and the center distance between any micropore and the six adjacent micropores is equal, and can be adjusted according to actual needs.

[0008] Preferably, the upward crystal planes of the non-polar GaN layer 101 and the N-type GaN three-dimensional triangular island 103 are both (11-20) planes. At this time, the crystal planes of the left and right inclined planes are both one of the {1-101} or {1-102} crystal plane families. Since the crystal plane families {1-101} or {1-102} are lower potential energy planes, a regular triangular island can be formed, and the layer structure above can grow regularly and controllably; in addition, the upward crystal planes of the non-polar GaN layer 101 and the N-type GaN three-dimensional triangular island 103 can also be (1-100) planes at the same time. At this time, the crystal planes of the left and right inclined planes are both {20-21} crystal plane families; the side surfaces of the N-type GaN three-dimensional triangular island 103 perpendicular to the bottom surface are both (000-1) planes.

[0009] Preferably, when the diameter of the micropores of the mask layer 102 is not greater than 1.5 μm, the diameter of the circumscribed circle of the N-type GaN three-dimensional triangular island 103 in the plane is adjusted between 5 and 20 μm as needed, because when the micropores are small, regular islands are easily formed, and the size of the island can be controlled as needed; when the diameter of the micropores of the mask layer 102 is greater than 1.5 μm, the diameter of the circumscribed circle of the N-type GaN three-dimensional triangular island 103 in the plane is 3 to 4 times the diameter of the micropores, but not more than 15 μm at most, because when the micropores are large, the islands are easily irregular, so the size of the islands is limited. Setting the island structure of the N-type GaN three-dimensional triangular island 103 is conducive to releasing the stress of the epitaxial material, improving the crystal quality of the HEMT structure, and weakening the influence of defects and polarization on carriers.

[0010] Preferably, the Al x Ga 1-x The N layer 104 is on the left and right inclined surfaces of the GaN three-dimensional triangular island 103, close to the side of the GaN three-dimensional triangular island 103, and extends along the

[0001] axis and has a coverage rate of 30% to 50% on the GaN three-dimensional triangular island 103, wherein the

[0001] axis is perpendicular to the side of the GaN three-dimensional triangular island 103 and is in the direction of one side of the inclined surface of the GaN three-dimensional triangular island 103, and the description method is also applicable to the remaining

[0001] axes; when the upward crystal plane of the GaN three-dimensional triangular island 103 is the (11-20) plane and the left and right inclined surfaces are of the {1-101} crystal plane family, the Al x Ga1-x The Al composition of the N layer 104 is 0.15 < x < 0.4, and the thickness is: 2 / x ± 5 nm. Since the angle between the (1-101) plane and the (0002) plane is about 61.9°, the polarization effect is relatively low, so a higher Al composition or thickness is required; when the upward crystal plane of the GaN three-dimensional triangular island 103 is the (11-20) plane and the left and right inclined planes are the {1-102} crystal plane family, Al x Ga 1-x The Al composition of the N layer 104 is 0.1 < x < 0.3, and the thickness is: 1.5 / x ± 5 nm. Since the angle between the (1-102) plane and the (0002) plane is 43°, the polarization effect is acceptable, so the required Al composition or thickness can be slightly smaller; when the upward crystal plane of the GaN three-dimensional triangular island 103 is the (1-100) plane and the left and right inclined planes are the {20-21} crystal plane family, Al x Ga 1-x The Al composition of the N layer 104 is 0.15 < x < 0.4, and the thickness is: 3 / x ± 5 nm. Since the angle between the (20-21) plane and the (0002) plane is 75°, the polarization effect is very small, so a higher Al composition or a thicker thickness is required.

[0011] The left and right A electrodes 106 are respectively at the bottom of the left and right inclined planes of the GaN three-dimensional triangular island 103, close to the side surface of the GaN three-dimensional triangular island 103, and the length extending along the

[0001] axis is the same as that of Al x Ga 1-x N layer 104; the common C electrode 108 is at the top of the GaN three-dimensional triangular island 103, close to the side surface of the GaN three-dimensional triangular island 103, and the length extending along the

[0001] axis is the same as that of Al x Ga 1-x N layer 104.

[0012] Preferably, when the thickness of the Al x Ga 1-x N layer 104 is greater than 20 nm, the left and right A electrodes 106 and the common C electrode 108 are in contact with the GaN three-dimensional triangular island 103 and Al x Ga 1-x N layer 104 at the same time; when the thickness of the Al x Ga 1-x N layer 104 is less than 20 nm, the left and right A electrodes 106 and the common C electrode 108 are in contact with Al x Ga 1-x N layer 104 at the same time. When the thickness of the Al x Ga 1-x N layer 104 is less than 20 nm, the A electrode 106 and the common C electrode 108 are in contact with Al x Ga 1-xThe N-layer 104 can generate sufficient current, so only the A electrode 106 and the common C electrode 108 need to be covered on the Al x Ga 1-x N-layer 104; When the thickness of the Al x Ga 1-x N-layer 104 is greater than 20 nm, the A electrode 106 and the common C electrode 108 cannot generate sufficient current when contacting the Al x Ga 1-x N-layer 104. Therefore, the positions of the A electrode 106 and the common C electrode 108 must be etched to expose the underlying GaN island 103, and the A electrode 106 and the common C electrode 108 are brought into contact with the triangular island 103.

[0013] Preferably, the insulating dielectric layer 105 covers the Al x Ga 1-x N-layer 104, close to the side of the GaN three-dimensional triangular island 103, and the length extending along the

[0001] axis is the same as that of the Al x Ga 1-x N-layer 104; The left and right B electrodes 107 are respectively in contact with the left and right insulating dielectric layers 105, close to the side of the GaN three-dimensional triangular island 103, and the length extending along the

[0001] axis is the same as that of the Al x Ga 1-x N-layer 104.

[0014] Preferably, the insulating dielectric layer 105 covers the Al x Ga 1-x N-layer 104 from one side of the A electrode 106, with a coverage rate > 30%, and the B electrode 107 is close to the side of the A electrode 106; or the insulating dielectric layer 105 covers the Al x Ga 1-x N-layer 104 from one side of the common C electrode 108, with a coverage rate > 30%, and the B electrode 107 is close to the side of the common C electrode 108; or the insulating dielectric layer 105 completely covers the Al x Ga 1-x N-layer 104. At this time, the B electrode 107 is close to either the A electrode 106 or the common C electrode 108.

[0015] On the other hand, the present invention provides a method for preparing a symmetric GaN-based HEMT structure, which is characterized in that the structure includes a GaN layer 101 with a non-polar upward crystal plane, a mask layer 102 containing a microporous array, a GaN three-dimensional triangular island 103, and an Al with a thickness less than 20 nm and an Al component of 0.1 < x < 0.4, which are sequentially arranged from bottom to top x Ga 1-xN layer 104, insulating dielectric layer 105, and A electrode 106 below GaN three-dimensional triangular island 103, B electrode 107 on insulating dielectric layer 105 and common C electrode 108 on top of GaN three-dimensional triangular island 103; wherein the bottom of GaN three-dimensional triangular island 103 is obtained by epitaxial growth upward from the micro-hole of mask layer 102, and includes two left-right symmetrical triangular inclined surfaces and a triangular side surface perpendicular to the bottom surface except the bottom; and Al x Ga 1-x The N layer 104, the insulating dielectric layer 105, the A electrode 106, and the B electrode 107 are all symmetrically arranged on the inclined surface of the GaN three-dimensional triangular island 103, and the parameters of the same structure are exactly the same; the Al x Ga 1-x N layer 104, insulating dielectric layer 105, A electrode 106, B electrode 107 and common C electrode 108 constitute HEMT structure L; Al x Ga 1-x The N layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 constitute a HEMT structure R. The method for preparing the transistor structure includes the following steps: a) preparing a non-polar GaN template as the non-polar GaN layer 101, or epitaxially growing a non-polar GaN film on a sapphire, Si or SiC substrate as the non-polar GaN layer 101; b) preparing a dielectric film on the non-polar GaN layer 101, and using micro-machining technology to process a micro-pore structure on the dielectric layer to form a mask layer 102 containing a micro-pore array, exposing the non-polar GaN layer 101 below; c) using the selective epitaxial growth technology to perform selective epitaxy using the micropores, and then controlling the temperature of the epitaxial growth, The V / III ratio, the reaction chamber pressure, the carrier gas and the flow rate of the reactant source are adjusted to achieve lateral epitaxy to form GaN islands 103; d) Using one of the techniques of chemical vapor deposition, epitaxial growth, evaporation coating, and magnetron sputtering, combined with micromachining technology, to prepare Al on the GaN island 103 x Ga 1-x N layer 104; e) Use one of the following technologies: chemical vapor deposition, epitaxial growth, evaporation coating, magnetron sputtering, combined with micromachining technology, to produce Al x Ga 1-x An insulating dielectric layer 105 is formed on the N layer 104; f) Using thin film deposition technology combined with microfabrication technology, metal thin films are deposited at the corresponding positions of the A electrode 106, the B electrode 107, and the common C electrode 108 to prepare the A electrode 106, the B electrode 107, and the common C electrode 108, thus completing the preparation of this symmetric GaN-based HEMT structure.

[0016] The present invention also provides a method for preparing a symmetric GaN-based HEMT structure, which is characterized in that: the structure includes a GaN layer 101 with a non-polar upward crystal plane, a mask layer 102 containing a microporous array, a GaN three-dimensional triangular island 103, an AlGaN layer 104 with a thickness greater than 20 nm and an Al composition of 0.1 < x < 0.4, an insulating dielectric layer 105, which are sequentially arranged from bottom to top; and an A electrode 106 below the GaN three-dimensional triangular island 103, a B electrode 107 on the insulating dielectric layer 105, and a common C electrode 108 on the top of the GaN three-dimensional triangular island 103; among them, the bottom of the GaN three-dimensional triangular island 103 is epitaxially grown upward from the micropores of the mask layer 102, and except for the bottom, it includes two left and right symmetric triangular inclined planes and a triangular side perpendicular to the bottom surface; moreover, x Ga 1-x the AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, and the B electrode 107 are all symmetrically arranged on the inclined plane of the GaN three-dimensional triangular island 103, and the parameters of the same structure are exactly the same; the left AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107, and the common C electrode 108 form a HEMT structure L; the right AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107, and the common C electrode 108 form a HEMT structure R. The preparation method of this transistor structure includes the following steps: x Ga 1-x the AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, and the B electrode 107 are all symmetrically arranged on the inclined plane of the GaN three-dimensional triangular island 103, and the parameters of the same structure are exactly the same; the left AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107, and the common C electrode 108 form a HEMT structure L; the right AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107, and the common C electrode 108 form a HEMT structure R. x Ga 1-x the AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107, and the common C electrode 108 form a HEMT structure L; the right AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107, and the common C electrode 108 form a HEMT structure R. x Ga 1-x the AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107, and the common C electrode 108 form a HEMT structure R. The preparation method of this transistor structure includes the following steps: a) Prepare a non-polar GaN template as the GaN layer 101 with a non-polar surface, or epitaxially grow a non-polar GaN thin film on a sapphire, Si, or SiC substrate as the GaN layer 101 with a non-polar surface; b) Prepare a dielectric thin film on the GaN layer 101 with a non-polar surface. Using microfabrication process technology, a microporous structure is processed on the dielectric layer to expose the underlying GaN layer 101 with a non-polar surface; c) Use selective area epitaxial growth technology to perform selective area epitaxy using the above micropores, and then realize lateral epitaxy by controlling conditions such as the epitaxial growth temperature, V / III ratio, reaction chamber pressure, carrier gas, and the flow rate of the reactant source to form a GaN island 103; d) Using one of the techniques of chemical vapor deposition, epitaxial growth, evaporation coating, and magnetron sputtering, combined with micromachining technology, to prepare Al on the GaN island 103 x Ga 1-x N layer 104; e) Use one of the following technologies: chemical vapor deposition, epitaxial growth, evaporation coating, magnetron sputtering, combined with micromachining technology, to produce Al x Ga 1-x An insulating dielectric layer 105 is formed on the N layer 104; f) Using micromachining technology, the insulating dielectric layer 105 and Al x Ga 1-x N layer 104 in GaN three-dimensional triangle island The side of the triangle 103 perpendicular to the bottom surface and the location where the A electrode 106 and the common C electrode 108 are to be prepared are etched to expose the GaN island 103 below; then the A electrode 106 and the B electrode 107 are completed by using thin film deposition technology. and the preparation of the common C electrode 108 to complete the preparation of this symmetrical GaN-based HEMT structure.

[0017] Beneficial effects:

[0018] The present invention utilizes selective area epitaxy combined with lateral epitaxy to obtain a three-dimensional GaN island. The GaN island naturally forms a bilaterally symmetrical structure due to its crystal properties. Based on this feature, the HEMTs prepared in pairs have atomic-level consistency, and the bilaterally symmetrical semi-polar AlGaN / GaN heterojunction produces a 2DEG with easily controlled concentration, which can achieve high-quality, high-performance, and highly consistent paired GaN-based HEMTs. In circuit applications such as mirror current source and differential amplifier, the paired GaN HEMTs have better consistency and stability than traditional devices.

[0019] At the same time, the present invention sets Al x Ga 1-x When the thickness of the N layer 104 is greater than 20 nm, the positions of the A electrode 106 and the common C electrode 108 are etched so that the electrodes are in contact with the GaN islands, so that sufficient current is generated. x Ga 1-x When the thickness of the N layer 104 is less than 20 nm, there is no need to etch the positions of the A electrode 106 and the common C electrode 108, thereby reducing process operations.

[0020] It is stipulated that when the micropore diameter of the mask layer 102 is not greater than 1.5 μm, the circumscribed circle diameter of the N-type GaN three-dimensional triangular island 103 in the plane can be adjusted between 5 and 20 μm as needed. Because when the micropores are small, regular islands are easily formed, and at this time, the size of the islands can be controlled as needed; when the micropore diameter of the mask layer 102 is greater than 1.5 μm, the circumscribed circle diameter of the N-type GaN three-dimensional triangular island 103 in the plane is 3 to 4 times the micropore diameter, but not exceeding 15 μm at most. Because when the micropores are large, the islands are prone to be irregular, so the size of the islands is limited. And the island structure is beneficial to releasing the stress of the epitaxial material, improving the crystal quality of the HEMT structure, and weakening the influence of defects and polarization on carriers. When the upward crystal plane of the GaN three-dimensional triangular island 103 is the (11-20) plane and the left and right inclined planes are the {1-101} crystal plane family, since the angle between (1-101) and (0002) is 61.9°, the polarization effect is relatively low, so a higher Al component (0.15 < x < 0.4) or thickness (2 / x ± 5 nm) is required; when the upward crystal plane of the GaN three-dimensional triangular island 103 is the (11-20) plane and the left and right inclined planes are the {1-102} crystal plane family, since the angle between (1-102) and (0002) is 43°, the polarization effect is acceptable, so a lower Al component (0.1 < x < 0.3) or thickness (1.5 / x ± 5 nm) is required; when the upward crystal plane of the GaN three-dimensional triangular island 103 is the (1-100) plane and the left and right inclined planes are the {20-21} crystal plane family, since the angle between (20-21) and (0002) is 75°, the polarization effect is very small, so a higher Al component (0.15 < x < 0.4) or a thicker thickness (3 / x ± 5 nm) is required. By adjusting the Al x Ga 1-x N layer 104 with different components and thicknesses, the influence of the polarization effect can be reduced, the crystal quality can be improved, and the stability of the HEMT structure can be enhanced. Brief Description of the Drawings

[0021] Figure 1 A cross-sectional schematic view of a symmetric GaN-based HEMT structure provided by the present invention, where the upward crystal plane of the GaN layer is the (11-20) plane and the B electrode is placed on the top of the Al x Ga 1-x N layer.

[0022] Figure 2 A top view schematic diagram of a symmetric GaN-based HEMT structure provided by the present invention, where the upward crystal plane of the GaN layer is the (11-20) plane and the B electrode is placed on the top of the Al x Ga 1-x N layer.

[0023] Figure 3 A cross-sectional schematic view of a typical structure of a traditional GaN-based HEMT.

[0024] Figure 4 The present invention provides a GaN layer with a (1-100) upward crystal plane and a B electrode placed on an Al x Ga 1-x Schematic diagram of the cross-section of the symmetrical GaN-based HEMT structure at the bottom of the N layer

[0025] Figure 5 The present invention provides a GaN layer with a (1-100) upward crystal plane and a B electrode placed on an Al x Ga 1-x Schematic top view of the symmetrical GaN-based HEMT structure at the bottom of the N layer.

[0026] Among them, 101 is a GaN layer with a non-polar surface facing upward; 102 is a mask layer containing a microhole array; 103 is a GaN three-dimensional triangular island; 104 is an Al x Ga 1-x N layer; 105 is an insulating dielectric layer; 106 is an A electrode; 107 is a B electrode; 108 is a common C electrode; 201 is a substrate; 202 is a buffer layer; 203 is GaN; 204 is AlGaN; 205 is a source electrode; 206 is a gate electrode; and 207 is a drain electrode. DETAILED DESCRIPTION

[0027] The present invention will be further described below in conjunction with the accompanying drawings. The following embodiments are only used to more clearly illustrate the technical solution of the present invention, and cannot be used to limit the protection scope of the present invention.

[0028] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0029] Embodiment 1:

[0030] Embodiment 1 of the present invention provides a GaN layer with an upward crystal plane of (11-20) and a B electrode placed on an Al x Ga 1-x The cross-sectional view of the symmetrical GaN-based HEMT structure on the top of the N layer is shown in Figure 1 As shown, the top view diagram is as follows Figure 2As shown, the symmetrical GaN-based HEMT structure includes a non-polar GaN layer 101 with the upward crystal plane being the (11-20) plane, a mask layer 102 containing a microhole array, a GaN three-dimensional triangular island 103, an Al component x=0.15, and a GaN film 104. x Ga 1-x N layer 104, insulating dielectric layer 105, and A electrode 106 below GaN three-dimensional triangular island 103, B electrode 107 on insulating dielectric layer 105 and common C electrode 108 on top of GaN three-dimensional triangular island 103; wherein the bottom of GaN three-dimensional triangular island 103 is obtained by epitaxial growth upward from the micro-hole of mask layer 102, and includes two left-right symmetrical triangular inclined surfaces and a triangular side surface perpendicular to the bottom surface except the bottom; and Al x Ga 1-x The N layer 104, the insulating dielectric layer 105, the A electrode 106, and the B electrode 107 are all symmetrically arranged on the inclined surface of the GaN three-dimensional triangular island 103, and the parameters of the same structure are exactly the same; the Al x Ga 1-x N layer 104, insulating dielectric layer 105, A electrode 106, B electrode 107 and common C electrode 108 constitute HEMT structure L; Al x Ga 1-x The N layer 104 , the insulating dielectric layer 105 , the A electrode 106 , the B electrode 107 and the common C electrode 108 constitute a HEMT structure R.

[0031] The upward crystal planes of the GaN layer 101 and the GaN three-dimensional triangular island 103 are both (11-20) planes, the crystal planes of the left and right inclined planes are both {1-102} crystal plane family, and the diameter of the circumscribed circle of the GaN three-dimensional triangular island 103 within the plane is 10 μm.

[0032] A 30nm thick SiO2 dielectric film is plated on the GaN layer 101 with the upward crystal plane (11-20) as a mask layer 102, and a microhole array is etched from top to bottom through process technology, exposing the underlying GaN layer 101 in the microholes. The diameter of the microholes in the mask layer 102 is 1μm.

[0033] Al x Ga 1-x The N layer 104 covers the left and right inclined surfaces of the GaN three-dimensional triangular island 103, with an Al composition x=0.15 and a thickness of 15 nm.

[0034] The left and right A electrodes 106 are respectively at the bottom of the inclined surface on the left and right sides of the GaN three-dimensional triangular island 103, and the common C electrode 108 is at the top of the GaN three-dimensional triangular island 103. The left and right A electrodes 106 and the common C electrode 108 are connected to the Al x Ga 1-xN layer 104 is in contact.

[0035] The insulating dielectric layer 105 covers the Al x Ga 1-x On the N layer 104, the left and right B electrodes 107 are in contact with the left and right insulating dielectric layers 105 respectively. The insulating dielectric layer 105 covers the Al from one side of the common C electrode 108. x Ga 1-x The N layer 104 has a coverage rate of 50%, and the B electrode 107 is close to the common C electrode 108.

[0036] Embodiment 1 of the present invention provides a GaN layer with an upward crystal plane of (11-20) and a B electrode placed on an Al x Ga 1-x The method for preparing a symmetrical GaN-based HEMT structure on top of the N layer includes the following steps: a) preparing a non-polar (11-20) face GaN template as the non-polar face GaN layer 101, the non-polar face GaN layer The upward crystal planes of 101 and N-type GaN three-dimensional triangular island 103 are (11-20) planes, and the left and right inclined planes are {1-102} crystal plane family; b) a layer of SiO2 dielectric film is prepared on the non-polar GaN layer 101, and a micro-machining process is used to process a micro-pore structure on the dielectric layer to form a mask layer 102 containing a micro-pore array, wherein the diameter of the micro-pore is 1 μm, exposing the non-polar GaN layer 101 below; c) using the selective epitaxial growth technology to perform selective epitaxy using the micropores, and then controlling the temperature of the epitaxial growth, The V / III ratio, the reaction chamber pressure, the carrier gas and the flow rate of the reactant source are adjusted to achieve lateral epitaxy to form GaN islands 103. The diameter of the circumscribed circle of the N-type GaN three-dimensional triangular island 103 in the plane is 10 μm. d) epitaxial growth technology is used in combination with micromachining technology to prepare Al component x = 0.15 and thickness 15nm Al x Ga 1-x N layer 104; e) Chemical vapor deposition technology is used in combination with micromachining technology to x Ga 1-x An insulating dielectric layer is formed on the N layer 104 105. The insulating dielectric layer 105 covers the Al from one side of the common C electrode 108. x Ga 1-x N layer 104, with a coverage of 50%, and B electrode 107 close to the common C electrode 108; f) Using thin film deposition technology combined with micromachining technology, metal thin film deposition is performed at positions corresponding to the A electrode 106, the B electrode 107 and the common C electrode 108 to prepare the A electrode 106, the B electrode 107 and the common C electrode 108, thereby completing the preparation of this symmetrical GaN-based HEMT structure.

[0037] Embodiment 2:

[0038] Embodiment 2 of the present invention provides a GaN layer with a (1-100) upward crystal plane and a B electrode disposed on an Al x Ga 1-x The cross-sectional view of the symmetrical GaN-based HEMT structure at the bottom of the N layer is shown in Figure 4 As shown, the top view diagram is as follows Figure 5 As shown, the symmetrical GaN-based HEMT structure includes a non-polar GaN layer 101 with the upward crystal plane being the (1-100) plane, a mask layer 102 containing a microhole array, a GaN three-dimensional triangular island 103, an Al component x=0.16, and a GaN film 104. x Ga 1-x N layer 104, insulating dielectric layer 105, and A electrode 106 below GaN three-dimensional triangular island 103, B electrode 107 on insulating dielectric layer 105 and common C electrode 108 on top of GaN three-dimensional triangular island 103; wherein the bottom of GaN three-dimensional triangular island 103 is obtained by epitaxial growth upward from the micro-hole of mask layer 102, and includes two left-right symmetrical triangular inclined surfaces and a triangular side surface perpendicular to the bottom surface except the bottom; and Al x Ga 1-x The N layer 104, the insulating dielectric layer 105, the A electrode 106, and the B electrode 107 are all symmetrically arranged on the inclined surface of the GaN three-dimensional triangular island 103, and the parameters of the same structure are exactly the same; the Al x Ga 1-x N layer 104, insulating dielectric layer 105, A electrode 106, B electrode 107 and common C electrode 108 constitute HEMT structure L; Al x Ga 1-x The N layer 104 , the insulating dielectric layer 105 , the A electrode 106 , the B electrode 107 and the common C electrode 108 constitute a HEMT structure R.

[0039] The upward crystal planes of the GaN layer 101 and the GaN three-dimensional triangular island 103 are both (1-100) planes, the crystal planes of the left and right inclined planes are both {20-21} crystal plane family, and the diameter of the circumscribed circle of the GaN three-dimensional triangular island 103 within the plane is 10 μm.

[0040] A 30nm thick SiO2 dielectric film is plated on the GaN layer 101 with the upward crystal plane (1-100) as a mask layer 102, and a microhole array is etched from top to bottom through process technology, exposing the underlying GaN layer 101 in the microholes. The diameter of the microholes in the mask layer 102 is 1μm.

[0041] Al x Ga 1-x The N layer 104 covers the left and right inclined surfaces of the GaN three-dimensional triangular island 103, and has an Al composition x=0.16 and a thickness of 22 nm.

[0042] The left and right A electrodes 106 are respectively at the bottom of the inclined surface on the left and right sides of the GaN three-dimensional triangular island 103, and the common C electrode 108 is at the top of the GaN three-dimensional triangular island 103. The left and right A electrodes 106 and the common C electrode 108 are connected to the GaN three-dimensional triangular island 103 and the Al x Ga 1-x N layer 104 is in contact.

[0043] The insulating dielectric layer 105 covers the Al x Ga 1-x On the N layer 104, the left and right B electrodes 107 are in contact with the left and right insulating dielectric layers 105 respectively. The insulating dielectric layer 105 covers the Al electrode 106 from one side. x Ga 1-x The N layer 104 has a coverage rate of 50%, and the B electrode 107 is close to the A electrode 106 side.

[0044] Embodiment 2 of the present invention provides a GaN layer with a (1-100) upward crystal plane and a B electrode disposed on an Al x Ga 1-x The method for preparing a symmetrical GaN-based HEMT structure at the bottom of the N layer includes the following steps: a) preparing a non-polar (1-100)-plane GaN template as the non-polar GaN layer 101, the non-polar GaN layer 101 and the N-type GaN three-dimensional triangular island 103 have the (1-100) plane facing upward, and the left and right inclined planes are {20-21} crystal plane family; b) a SiO2 dielectric film is prepared on the non-polar GaN layer 101, and a micro-machining process is used to process a micro-pore structure on the dielectric layer, wherein the diameter of the micro-pore is 1 μm, exposing the non-polar GaN layer 101 below; c) using the selective epitaxial growth technology to perform selective epitaxy using the micropores, and then controlling the temperature of the epitaxial growth, The V / III ratio, the reaction chamber pressure, the carrier gas and the flow rate of the reactant source are adjusted to achieve lateral epitaxy to form GaN islands 103. The diameter of the circumscribed circle of the N-type GaN three-dimensional triangular island 103 in the plane is 10 μm. d) Using epitaxial growth technology and micromachining technology, an Al layer with an Al component x=0.16 and a thickness of 22 nm is prepared on the GaN island 103. x Ga 1-x N layer 104; e) Chemical vapor deposition technology is used in combination with micromachining technology to x Ga 1-x An insulating dielectric layer 105 is formed on the N layer 104. The insulating dielectric layer 105 covers the Al electrode 106 from one side. x Ga 1-x N layer 104, with a coverage of 50%, and B electrode 107 close to the A electrode 106; f) Using micromachining technology, the insulating dielectric layer 105 and Al x Ga 1-x The N layer 104 is etched on one side of the triangular side of the GaN three-dimensional triangular island 103 which is perpendicular to the bottom surface and where the A electrode 106 and the common C electrode 108 are required to be prepared, exposing the GaN island 103 below; then the A electrode 106 and the B electrode 107 are completed by using thin film deposition technology. and the preparation of the common C electrode 108 to complete the preparation of this symmetrical GaN-based HEMT structure.

Claims

1. A symmetrical GaN-based HEMT structure, characterized in that: It includes a GaN layer 101 with a non-polar surface as the upward crystal plane arranged from bottom to top, a mask layer 102 containing a microporous array, GaN three-dimensional triangular islands 103, an AlGaN layer 104 with an Al component of 0.1 < x < 0.4, an insulating dielectric layer 105, an A electrode 106 below the GaN three-dimensional triangular islands 103, a B electrode 107 on the insulating dielectric layer 105, and a common C electrode 108 on the top of the GaN three-dimensional triangular islands 103; among them, the bottom of the GaN three-dimensional triangular islands 103 is epitaxially grown upward from the micropores of the mask layer 102 and includes two symmetric triangular inclined planes and a triangular side perpendicular to the bottom surface except for the bottom; moreover, x , 1-x , x , 1-x , x , 1-x Ga 1-x the AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106 and the B electrode 107 are symmetrically arranged on the inclined planes of the GaN three-dimensional triangular islands 103, and the parameters of the same structure are exactly the same; the left AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 form a HEMT structure L; the right AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 form a HEMT structure R. x Ga 1-x the AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106 and the B electrode 107 are symmetrically arranged on the inclined planes of the GaN three-dimensional triangular islands 103, and the parameters of the same structure are exactly the same; the left x Ga 1-x the AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 form a HEMT structure L; the right x Ga 1-x the AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 form a HEMT structure R.

2. A symmetrical GaN-based HEMT structure according to claim 1, characterized in that: The mask layer 102 containing the microhole array is formed by etching a 5-50 nm thick SiO2, SiN or hBN dielectric film on the GaN layer 101 with the upward crystal surface being the non-polar surface, and then etching the microhole array from top to bottom through a process technology, so that the GaN layer 101 at the bottom is exposed in the microholes; The diameter of the micropores is between 0.5 and 5 μm, and the micropores are arranged in a close-packed form. The center distances of any micropore and the six adjacent micropores are equal and can be adjusted according to actual needs.

3. A symmetrical GaN-based HEMT structure according to claim 1, characterized in that: The upward crystal planes of the GaN layer 101 and the GaN three-dimensional triangular island 103 are both (11-20) planes, and the crystal planes of the left and right inclined planes are both {1-101} or {1-102} crystal plane families; in addition, the upward crystal planes of the GaN layer 101 and the GaN three-dimensional triangular island 103 can also be (1-100) planes, and the crystal planes of the left and right inclined planes are both {20-21} crystal plane families; the side surfaces of the GaN three-dimensional triangular island 103 perpendicular to the bottom surface are both (000-1) planes; when the micropore diameter of the mask layer 102 is not greater than 1.5μm, the diameter of the circumscribed circle of the GaN three-dimensional triangular island 103 within the plane is adjusted between 5 and 20μm according to needs; when the micropore diameter of the mask layer 102 is greater than 1.5μm, the diameter of the circumscribed circle of the GaN three-dimensional triangular island 103 within the plane is 3 to 4 times the diameter of the micropore, but the maximum does not exceed 15μm.

4. A symmetrical GaN-based HEMT structure according to claim 1, characterized in that: Al x Ga 1-x The AlGaN layer 104 is on the two left and right inclined planes of the GaN three-dimensional triangular island 103, adjacent to the side surfaces of the GaN three-dimensional triangular island 103, extends along the [0001] axis, and the coverage rate of the GaN three-dimensional triangular island 103 is between 30% and 50%; when the upward crystal plane of the GaN three-dimensional triangular island 103 is the (11-20) plane and the two left and right inclined planes are the {1-101} crystal plane family, Al x Ga 1-x The Al composition of the AlGaN layer 104 satisfies 0.15 < x < 0.4, and the thickness is: 2 / x ± 5 nm; when the upward crystal plane of the GaN three-dimensional triangular island 103 is the (11-20) plane and the two left and right inclined planes are the {1-102} crystal plane family, Al x Ga 1-x The Al composition of the AlGaN layer 104 satisfies 0.1 < x < 0.3, and the thickness is: 1.5 / x ± 5 nm; when the upward crystal plane of the GaN three-dimensional triangular island 103 is the (1-100) plane and the two left and right inclined planes are the {20-21} crystal plane family, Al x Ga 1-x The Al composition of the AlGaN layer 104 satisfies 0.15 < x < 0.4, and the thickness is: 3 / x ± 5 nm.

5. A symmetrical GaN-based HEMT structure according to claim 1, characterized in that: The left and right A electrodes 106 are respectively located at the bottom of the inclined surface on the left and right sides of the GaN three-dimensional triangular island 103, close to the side of the GaN three-dimensional triangular island 103, and the length extending along the [0001] axis is the same as that of the Al x Ga 1-x The common C electrode 108 is on the top of the GaN three-dimensional triangular island 103, close to the side of the GaN three-dimensional triangular island 103, and the length extending along the [0001] axis is the same as that of the Al x Ga 1-x N layer 104 is consistent; when Al x Ga 1- x When the thickness of the N layer 104 is greater than 20 nm, the two A electrodes 106 on the left and right and the common C electrode 108 are simultaneously connected to the GaN three-dimensional triangle island 103 and the Al x Ga 1-x N layer 104 contacts; when Al x Ga 1-x When the thickness of the N layer 104 is less than 20 nm, the two A electrodes 106 on the left and right and the common C electrode 108 are simultaneously connected to the Al x Ga 1-x N layer 104 is in contact.

6. A symmetrical GaN-based HEMT structure according to claim 1, characterized in that: The insulating dielectric layer 105 covers the Al x Ga 1-x The N layer 104 is close to the side of the GaN three-dimensional triangular island 103 and has a length extending along the [0001] axis equal to that of the Al x Ga 1-x The left and right B electrodes 107 are in contact with the insulating dielectric layers 105 on the left and right sides, respectively, close to the side of the GaN three-dimensional triangular island 103, and the length extending along the [0001] axis is the same as that of the Al x Ga 1-x The N layer 104 is consistent; the insulating dielectric layer 105 covers the Al from one side of the A electrode 106; x Ga 1-x N layer 104, coverage> 30%, B electrode 107 close to A electrode 106 side; or insulating dielectric layer 105 covers Al from the common C electrode 108 side x Ga 1-x N layer 104, coverage> 30%, B electrode 107 close to the common C electrode 108 side; or the insulating dielectric layer 105 completely covers Al x Ga 1-x N layer 104 , at this time, the B electrode 107 is close to any side of the A electrode 106 or the common C electrode 108 .

7. A method for preparing a symmetrical GaN-based HEMT structure, characterized in that: The structure includes a GaN layer 101 with a non-polar upward crystal plane arranged from bottom to top, a mask layer 102 containing a microporous array, GaN three-dimensional triangular islands 103, an Al x Ga 1-x N layer 104 with a thickness less than 20 nm and an Al component of 0.1 < x < 0.4, an insulating dielectric layer 105, an A electrode 106 below the GaN three-dimensional triangular islands 103, a B electrode 107 on the insulating dielectric layer 105, and a common C electrode 108 on the top of the GaN three-dimensional triangular islands 103; among them, the bottom of the GaN three-dimensional triangular islands 103 is obtained by epitaxial growth upward from the micropores of the mask layer 102, and except for the bottom, it includes two symmetric triangular inclined planes and a triangular side perpendicular to the bottom surface; moreover, Al x Ga 1-x The N layer 104, the insulating dielectric layer 105, the A electrode 106, and the B electrode 107 are all symmetrically arranged on the inclined planes of the GaN three-dimensional triangular islands 103, and the parameters of the same structure are exactly the same; the left Al x Ga 1-x The N layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107, and the common C electrode 108 form a HEMT structure L; the right Al x Ga 1-x The N layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107, and the common C electrode 108 form a HEMT structure R. The preparation method of this transistor structure includes the following steps: a) preparing a GaN template with a non-polar upward crystal plane as the non-polar GaN layer 101, or epitaxially growing a non-polar GaN film on a sapphire, Si or SiC substrate as the non-polar GaN layer 101; b) preparing a dielectric film on the GaN layer 101, and using micro-machining technology to process a micro-hole structure on the dielectric layer to form a mask layer 102 containing a micro-hole array, exposing the GaN layer 101 below; c) using the selective epitaxial growth technology to perform selective epitaxy using the micropores, and then achieving lateral epitaxy by controlling the epitaxial growth temperature, V / III ratio, reaction chamber pressure, carrier gas, and reactant source flow rates to form GaN islands 103; d) Using one of the techniques of chemical vapor deposition, epitaxial growth, evaporation coating, and magnetron sputtering, combined with micromachining technology, to prepare Al on the GaN island 103 x Ga 1-x N layer 104; e) Use one of the following technologies: chemical vapor deposition, epitaxial growth, evaporation coating, magnetron sputtering, combined with micromachining technology, to produce Al x Ga 1-x An insulating dielectric layer 105 is formed on the N layer 104; f) Using thin film deposition technology combined with micromachining technology, metal thin film deposition is performed at positions corresponding to the A electrode 106, the B electrode 107 and the common C electrode 108 to prepare the A electrode 106, the B electrode 107 and the common C electrode 108, thereby completing the preparation of this symmetrical GaN-based HEMT structure.

8. A method for preparing a symmetrical GaN-based HEMT structure, characterized in that: The structure includes a GaN layer 101 with a non-polar surface as the upward crystal plane arranged from bottom to top, a mask layer 102 containing a microporous array, GaN three-dimensional triangular islands 103, an AlGaN layer 104 with a thickness greater than 20 nm and an Al component of 0.1 < x < 0.4, an insulating dielectric layer 105, an A electrode 106 below the GaN three-dimensional triangular islands 103, a B electrode 107 on the insulating dielectric layer 105, and a common C electrode 108 on the top of the GaN three-dimensional triangular islands 103. It is necessary to etch the positions of the A electrode 106 and the common C electrode 108 to expose the underlying GaN islands 103. Among them, the bottom of the GaN three-dimensional triangular islands 103 is obtained by epitaxial growth upward from the micropores of the mask layer 102, and except for the bottom, it includes two symmetric triangular inclined planes and a triangular side perpendicular to the bottom surface. Moreover, x Ga 1-x the AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106 and the B electrode 107 are all symmetrically arranged on the inclined planes of the GaN three-dimensional triangular islands 103, and the parameters of the same structure are exactly the same. The left-side AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 form a HEMT structure L. The right-side AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 form a HEMT structure R. The preparation method of this transistor structure includes the following steps: x Ga 1-x the AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106 and the B electrode 107 are symmetrically arranged on the inclined planes of the GaN three-dimensional triangular islands 103, and the parameters of the same structure are exactly the same. The left-side AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 form a HEMT structure L. The right-side AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 form a HEMT structure R. The preparation method of this transistor structure includes the following steps: x Ga 1-x the AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 form a HEMT structure L. The right-side AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 form a HEMT structure R. The preparation method of this transistor structure includes the following steps: x Ga 1-x the AlGaN layer 104, the insulating dielectric layer 105, the A electrode 106, the B electrode 107 and the common C electrode 108 form a HEMT structure R. The preparation method of this transistor structure includes the following steps: a) preparing a GaN template with a non-polar upward crystal surface as the GaN layer 101, or epitaxially growing a GaN film with a non-polar upward crystal surface on a sapphire, Si or SiC substrate as the GaN layer 101; b) preparing a dielectric film on the GaN layer 101, and using micromachining technology to process a microporous structure on the dielectric layer to expose the GaN layer 101 below; c) using the selective epitaxial growth technology to perform selective epitaxy using the micropores, and then achieving lateral epitaxy by controlling the epitaxial growth temperature, V / III ratio, reaction chamber pressure, carrier gas, and reactant source flow rates to form GaN islands 103; d) Using one of the techniques of chemical vapor deposition, epitaxial growth, evaporation coating, and magnetron sputtering, combined with micromachining technology, to prepare Al on the GaN island 103 x Ga 1-x N layer 104; e) Use one of the following technologies: chemical vapor deposition, epitaxial growth, evaporation coating, magnetron sputtering, combined with micromachining technology, to produce Al x Ga 1-x An insulating dielectric layer 105 is formed on the N layer 104; f) Using micromachining technology, the insulating dielectric layer 105 and Al x Ga 1-x The N layer 104 is etched on one side of the triangular side surface of the GaN three-dimensional triangular island 103 which is perpendicular to the bottom surface and at the position where the A electrode 106 and the common C electrode 108 are required to be prepared, exposing the GaN island 103 below; then, a thin film deposition technique is used to complete the preparation of the A electrode 106, the B electrode 107 and the common C electrode 108, thereby completing the preparation of this symmetrical GaN-based HEMT structure.

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