A preparation method of an n-type gallium nitride-based GAA-HEMT inverter

Abstract

The application discloses a preparation method of an n-type gallium nitride-based GAA-HEMT inverter, and comprises the following steps: S1, growing aluminum oxide on a GaN single crystal substrate, etching the middle part of the barrier layer and depositing a metal gate; S2, etching the middle part of the gate to form a groove, depositing aluminum oxide, etching the middle and both sides of the aluminum oxide, growing GaN nanosheets in the etching area, doping Si after growing AlGaN nanosheets, growing GaN nanosheets to form p-GaN nanosheets by doping Mg; S3, etching the p-GaN nanosheets to make the width of the p-GaN nanosheets same as that of the gate, evaporating a metal film in the thickness direction of the two layers of nanosheets to prepare a source electrode and a drain electrode, growing aluminum oxide on the surface of the device to cover the p-GaN nanosheets and the AlGaN nanosheets, depositing a metal gate to cover the aluminum oxide to form an E-mode GaN; and S4, growing aluminum oxide, etching the middle part of the aluminum oxide to deposit a metal gate, and preparing GaN nanosheets, AlGaN nanosheets, a source electrode and a drain electrode in the manner of S2 and S3, growing aluminum oxide to cover the AlGaN nanosheets, depositing a metal gate to cover the aluminum oxide to obtain a D-mode GaN with a GAA structure.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor technology, and particularly relates to a method for fabricating an n-type gallium nitride-based GAA-HEMT inverter. Background Technology

[0002] Silicon chips have a wide range of applications, but the electron and hole migration speeds of silicon materials are difficult to meet the demands of higher-performance semiconductor devices, especially high-speed, low-latency devices. Furthermore, the finned transistor structure, currently the most common type used in transistors, has become insufficient for gate control beyond the 5-nanometer node. Leakage becomes particularly pronounced as the size shrinks further, resulting in high static power consumption and significant heat generation. Gate all-around (GGA) structures can further enhance gate control, reduce leakage, and lower power consumption.

[0003] Gallium nitride (GaN) possesses a wide bandgap, strong atomic bonds, high thermal conductivity, stable chemical properties, strong radiation resistance, a wurtzite-like structure, and high hardness. GaN materials exhibit higher electron mobility, saturated electron velocity, and breakdown electric field, making them well-suited for applications in optoelectronics, high-temperature high-power devices, and high-frequency microwave devices. High Electron Mobility Transistors (HEMTs), as representatives of wide-bandgap power semiconductor devices, have enormous potential in high-frequency power applications. Due to the material's advantages, GaN power devices can achieve lower on-resistance and gate charge (meaning superior conduction and switching performance). Therefore, GaN power devices are more suitable for high-frequency applications, significantly improving converter efficiency and power density. Currently, GaN power devices are mainly used in power adapters, vehicle charging, and data centers, and are gradually becoming the optimal solution for 5G base station power supplies.

[0004] GaN devices can be classified into two types according to their operating modes: normally on (depletion-mode, D-mode) and normally off (enhancement-mode, E-mode). In the traditional lateral structure, the GaN HEMT structure composed of AlGaN / GaN heterojunctions includes a layer of high-mobility electrons: a two-dimensional electron gas (2DEG). The 2DEG forms a channel between the drain and source of the power device. There are two types of devices: normally on (depletion-mode, D-mode): When the gate-source voltage is zero, a 2DEG channel already exists between the drain and source, and the device is turned on. When the gate-source voltage is less than zero, the drain-source 2DEG channel is broken, and the device is turned off. Normally off (enhancement-mode, E-mode): When the gate-source voltage is greater than zero, a 2DEG channel is formed between the drain and source, and the device is turned on.

[0005] However, the electron and hole migration speeds of silicon are insufficient to meet the demands of higher-performance semiconductor devices, especially high-speed, low-latency devices. Gallium nitride (GaN) possesses advantages such as a wide bandgap, strong atomic bonds, high thermal conductivity, chemical stability, strong radiation resistance, a wurtzite-like structure, and high hardness, making it well-suited for applications in optoelectronics, high-temperature high-power devices, and high-frequency microwave devices. Due to these material advantages, GaN power devices can achieve lower on-resistance and gate charge. Therefore, GaN power devices are more suitable for high-frequency applications, significantly improving converter efficiency and power density. Currently, the finned transistor structure, commonly used in transistors, struggles to meet the required electrostatic control beyond the 5nm node. Leakage becomes more pronounced as the size shrinks further, resulting in high static power consumption and heat generation. The Gate All Around (GGA) structure further enhances gate control, reduces leakage, and lowers power consumption. Summary of the Invention

[0006] This invention provides a method for fabricating a GAA-HEMT inverter based on n-type gallium nitride, comprising:

[0007] S1. Alumina is grown on the surface of a semi-insulating self-supporting GaN single crystal substrate. After a barrier layer is fabricated, the middle part of the alumina is etched using reactive ion etching technology and a metal gate is deposited.

[0008] S2. Create a barrier layer by etching the middle part of the gate to form a groove, deposit aluminum oxide, create a barrier layer by etching the middle and both sides of the aluminum oxide, grow GaN nanosheets in the etched area, grow AlGaN nanosheets on the surface of GaN nanosheets and then dop Si, grow GaN nanosheets and dop Mg to form p-GaN nanosheets.

[0009] S3. Fabricate a barrier layer and etch p-GaN nanosheets so that the width of the p-GaN nanosheets is the same as that of the gate. Fabricate a barrier layer, deposit a metal film in the thickness direction of the two nanosheets to prepare the source and drain, and grow aluminum oxide on the surface of the formed device to cover the p-GaN nanosheets and AlGaN nanosheets. After depositing the metal gate, fabricate a barrier layer and cover it with aluminum oxide to form an E-mode GaN with a GAA structure.

[0010] S4. Alumina is grown on E-mode GaN to create a barrier layer. A metal gate is deposited in the middle of the alumina by etching. GaN nanosheets, AlGaN nanosheets, source and drain are prepared on the device surface in accordance with S2 and S3. Alumina is grown on the device surface and covered with AlGaN nanosheets to create a barrier layer. A metal gate is deposited to cover the alumina and form a D-mode GaN with a GAA structure.

[0011] Furthermore, the thickness of the p-GaN nanosheets is 10-30 nm.

[0012] Furthermore, the doping concentration of magnesium as a dopant is approximately 1-8 x 10⁻⁶. 17 cm -3 .

[0013] Furthermore, the thickness of the AlGaN nanosheets is 10-30 nm.

[0014] Furthermore, the doping concentration of silicon as a dopant is 1-8 x 10⁻⁶. 18 cm -3 .

[0015] Furthermore, the thickness of the gallium nitride substrate is 200-400 μm.

[0016] Furthermore, alumina is grown on the device surface using plasma-enhanced chemical vapor deposition or atomic layer deposition.

[0017] Furthermore, the thickness of the aluminum oxide gate insulating layer is 4-6 nm.

[0018] Furthermore, the GaN substrate can be replaced with a Si substrate, a SiC substrate, or a sapphire substrate.

[0019] Furthermore, the insulating layer can be replaced with silicon dioxide.

[0020] The beneficial effects of the embodiments of the present invention are as follows: The GAA-HEMT inverter based on n-type gallium nitride provided by the present invention has stronger channel control capability, lower leakage current, and lower static power consumption compared with traditional inverter structures. Compared with traditional silicon materials, gallium nitride materials and inverters made therefrom are more suitable for high-frequency applications, with lower on-resistance, which can increase switching frequency while reducing power density. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of fabricating a metal gate on a GaN single-crystal substrate.

[0023] Figure 2 This is a schematic diagram of the preparation of E-mode GaN.

[0024] Figure 3 A schematic diagram of the structure for preparing D-mode GaN.

[0025] Figure 4 This is a circuit connection diagram for an n-type gallium nitride (GaN) GAA-HEMT inverter.

[0026] Figure 5 This is a comparison chart showing the results of simulations of the traditional structure and this structure using simulation software. Detailed Implementation

[0027] To enable those skilled in the art to better understand the present invention, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0028] This invention provides a method for fabricating a GAA-HEMT inverter based on n-type gallium nitride, comprising:

[0029] S1. Alumina is grown on the surface of a semi-insulating self-supporting GaN single crystal substrate. After a barrier layer is fabricated, the middle part of the alumina is etched using reactive ion etching technology and a metal gate is deposited.

[0030] like Figure 1 As shown, Figure 1 This is a schematic diagram illustrating the fabrication of a metal gate on a GaN single-crystal substrate. In this embodiment of the invention, aluminum oxide (Al2O3) is grown on the device surface on a semi-insulating self-supporting GaN single-crystal substrate using plasma-enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD). A barrier layer is fabricated using photolithography, and the central aluminum oxide is etched using reactive ion etching (RIE) before the metal gate is deposited. Specifically, the thickness of the gallium nitride substrate is 200-400 μm. The thickness of the gate insulating layer aluminum oxide is 4-6 nm. The GaN substrate can be replaced with a Si substrate, a SiC substrate, or a sapphire substrate.

[0031] S2. Create a barrier layer by etching the middle part of the gate to form a groove, deposit aluminum oxide, create a barrier layer by etching the middle and both sides of the aluminum oxide, grow GaN nanosheets in the etched area, grow AlGaN nanosheets on the surface of GaN nanosheets and then dop Si, grow GaN nanosheets and dop Mg to form p-GaN nanosheets.

[0032] S3. Fabricate a barrier layer and etch p-GaN nanosheets so that the width of the p-GaN nanosheets is the same as that of the gate. Fabricate a barrier layer, deposit a metal film in the thickness direction of the two nanosheets to prepare the source and drain, and grow aluminum oxide on the surface of the formed device to cover the p-GaN nanosheets and AlGaN nanosheets. After depositing the metal gate, fabricate a barrier layer and cover it with aluminum oxide to form an E-mode GaN with a GAA structure.

[0033] like Figure 2 As shown, Figure 2 This is a schematic diagram of the preparation of E-mode GaN. In this embodiment of the invention, a barrier layer is fabricated using photolithography, the middle portion of the gate is etched to form a groove, and then aluminum oxide is deposited. The barrier layer is fabricated using photolithography, and the aluminum oxide in the middle and on both sides is etched. GaN nanosheets of 10 nm-200 nm, preferably 20 nm, are grown in the formed region using hydride vapor phase epitaxy (HVPE), molecular beam epitaxy (MBE), or metal-organic chemical vapor deposition (MOCVD).

[0034] AlGaN nanosheets of 10 nm–200 nm, preferably 20 nm, are grown on top of GaN nanosheets using hydride vapor phase epitaxy (HVPE), molecular beam epitaxy (MBE), or metal-organic chemical vapor deposition (MOCVD). Si is doped using diffusion or ion implantation to a doping concentration of approximately 1 x 10⁻⁶. 17 cm -3 -8x10 18 cm -3 Preferably 5x10 18 cm -3 GaN nanosheets of 10 nm–200 nm, preferably 20 nm, are grown on top of AlGaN nanosheets using hydride vapor phase epitaxy (HVPE), molecular beam epitaxy (MBE), or metal-organic chemical vapor deposition (MOCVD). Mg is doped using diffusion or ion implantation at a doping concentration of approximately 1 x 10⁻⁶. 17 cm -3 -8x10 18 cm -3 Preferably 5x10 18 cm -3 A p-GaN nanosheet is formed. A barrier layer is fabricated using photolithography, and the p-GaN nanosheet is etched to make the width of the p-GaN nanosheet the same as that of the gate.

[0035] A barrier layer was fabricated using photolithography. Metal films (e.g., Ni (25nm) / Au (25nm)) were deposited at both ends of the two nanosheets using methods such as thermal evaporation, magnetron sputtering, or electron beam evaporation to prepare the source and drain. Electrodes were formed using a lift-off process and then annealed at 650°C in an N2 environment. Aluminum oxide (Al2O3) was grown on the device surface using plasma-enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD) to cover the p-GaN and AlGaN nanosheets. A barrier layer was fabricated using photolithography, a metal gate was deposited, and then covered with aluminum oxide to form a GAA structure.

[0036] S4. Alumina is grown on E-mode GaN to create a barrier layer. A metal gate is deposited in the middle of the alumina by etching. GaN nanosheets, AlGaN nanosheets, source and drain are prepared on the device surface in accordance with S2 and S3. Alumina is grown on the device surface and covered with AlGaN nanosheets to create a barrier layer. A metal gate is deposited to cover the alumina and form a D-mode GaN with a GAA structure.

[0037] like Figure 3 As shown, Figure 3 This is a schematic diagram of the structure for fabricating D-mode GaN. In this embodiment of the invention, alumina (Al2O3) is grown above the E-mode using plasma-enhanced chemical vapor deposition (PECVD) or atomic layer deposition (ALD). A barrier layer is fabricated using photolithography, and the central alumina is etched using reactive ion etching (RIE) before depositing a metal gate. The fabrication methods in steps S1 and S2 are repeated to form GaN nanosheets and AlGaN nanosheets, as well as source and drain electrodes. Alumina (Al2O3) is then grown on the device surface using PECVD or ALD to cover the AlGaN nanosheets. Next, a barrier layer is fabricated using photolithography, a metal gate is deposited, and the alumina is covered to form a GAA structure. Specifically, the thickness of the p-GaN nanosheets is 10-30 nm. The thickness of the AlGaN nanosheets is 10-30 nm.

[0038] The n-type gallium nitride GAA-HEMT inverter structure prepared by this invention is as follows: Figure 3 As shown, 1. Gallium nitride substrate, 2. Gate, 3. Aluminum oxide, 4. GaN nanosheet, 5. AlGaN nanosheet, 6. p-GaN nanosheet, 7. Gate, 8. GaN nanosheet, 9. AlGaN nanosheet, 10. Aluminum oxide, 11. Metal electrode, 12. Aluminum oxide. Figure 4 This is a circuit connection diagram of an n-type gallium nitride (GaN) GAA-HEMT inverter. The device structure was simulated using simulation software, resulting in the following... Figure 5 The results shown, in which, Figure 5 The diagram shows the drain current test results for the conventional structure and the fully encircled gate (GAA) structure. It can be seen that the GAA structure has a smaller quiescent current compared to the conventional structure.

[0039] The GaA-HEMT inverter based on n-type gallium nitride (GaN) fabricated in this invention is characterized by the use of gallium nitride material and a fully all-around gate control nanosheet structure. Compared with conventional inverter structures, the fully all-around gate provides stronger channel control, lower leakage current, and lower quiescent power consumption. GaN material and the inverters fabricated thereon are more suitable for high-frequency applications, offering lower on-resistance, increased switching frequency, and reduced power density.

[0040] Obviously, the above embodiments are merely illustrative examples for clear explanation and are not intended to limit the implementation. Those skilled in the art will recognize that other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively list all possible implementations here. However, obvious variations or modifications derived therefrom are still within the scope of protection of this invention.

[0041] The above description is only a partial embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for fabricating a GAA-HEMT inverter based on n-type gallium nitride, characterized in that, include: S1. Alumina is grown on the surface of a semi-insulating self-supporting GaN single crystal substrate. After a barrier layer is fabricated, the middle part of the alumina is etched using reactive ion etching technology and a metal gate is deposited. S2. Create a barrier layer by etching the middle part of the gate to form a groove, deposit aluminum oxide, create a barrier layer by etching the middle and both sides of the aluminum oxide, grow GaN nanosheets in the etched area, grow AlGaN nanosheets on the surface of GaN nanosheets and then dop Si, grow GaN nanosheets and dop Mg to form p-GaN nanosheets. S3. Fabricate a barrier layer and etch p-GaN nanosheets so that the width of the p-GaN nanosheets is the same as that of the gate. Fabricate a barrier layer, deposit a metal film in the thickness direction of the two nanosheets to prepare the source and drain, and grow aluminum oxide on the surface of the formed device to cover the p-GaN nanosheets and AlGaN nanosheets. After depositing the metal gate, fabricate a barrier layer and cover it with aluminum oxide to form an E-mode GaN with a GAA structure. S4. Alumina is grown on E-mode GaN to create a barrier layer. A metal gate is deposited in the middle of the alumina by etching. GaN nanosheets, AlGaN nanosheets, source and drain are prepared on the device surface in accordance with S2 and S3. Alumina is grown on the device surface to cover the AlGaN nanosheets, creating a barrier layer. A metal gate is deposited to cover the alumina and form a D-mode GaN with a GAA structure.

2. The preparation method according to claim 1, characterized in that, The thickness of p-GaN nanosheets is 10-30 nm.

3. The preparation method according to claim 1, characterized in that, The doping concentration of Mg as a dopant is 1 x 10⁻⁶. 17 -8x10 18 cm -3 .

4. The preparation method according to claim 1, characterized in that, The thickness of AlGaN nanosheets is 10-30 nm.

5. The preparation method according to claim 1, characterized in that, The doping concentration using Si as the dopant is 1x10⁻⁶. 17 -8x10 18 cm -3 .

6. The preparation method according to claim 1, characterized in that, The thickness of the GaN single crystal substrate is 200-400 μm.

7. The preparation method according to claim 1, characterized in that, Alumina is grown on the device surface using plasma-enhanced chemical vapor deposition or atomic layer deposition.

8. The preparation method according to claim 1, characterized in that, GaN single crystal substrates can be replaced by Si substrates, SiC substrates, or sapphire substrates.

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