Gallium nitride device
By employing a composite barrier layer structure in gallium nitride devices, and using a second barrier layer as an etch stop layer to protect the first barrier layer, the problem of insufficient barrier layer thickness under the gate is solved, and the electrical performance of the device is improved, especially the mobility and saturation current of the two-dimensional electron gas.
Patent Information
- Application Number
- CN202423295984.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-30
- Publication Date
- 2025-12-23
- Estimated Expiration
- 2034-12-30
AI Technical Summary
In the fabrication process of existing concave-gate enhancement gallium nitride devices, the thickness of the barrier layer under the gate cannot be guaranteed, resulting in poor electrical performance, especially low threshold voltage and low carrier mobility.
A composite barrier layer structure is adopted, including a first barrier layer, a second barrier layer and a third barrier layer. The second barrier layer acts as an etch stop layer to protect the first barrier layer from over-etching, ensuring that the heterogeneous structure of the channel layer and the first barrier layer is not affected. An appropriate accommodating space is formed through the etching process to accommodate the gate.
This improved the two-dimensional electron gas mobility and saturation current of gallium nitride devices, thereby enhancing the electrical performance of the devices.
Smart Images
Figure CN223714495U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of semiconductor technology, and in particular to a gallium nitride device. Background Technology
[0002] Gallium nitride devices possess excellent electrical performance due to the high concentration of two-dimensional electron gas (2DEG) in the heterojunction formed by the channel layer and the barrier layer.
[0003] In recessed gate enhancement gallium nitride (GaN) devices, the thickness of the barrier layer beneath the gate cannot be guaranteed after the gate-accommodating structure is fabricated, resulting in poor electrical performance of the GaN device. Utility Model Content
[0004] This invention provides a gallium nitride device that ensures the thickness of the barrier layer under the gate meets the device requirements, thereby improving the electrical performance of the gallium nitride device.
[0005] According to one aspect of the present invention, a gallium nitride device is provided, comprising:
[0006] Substrate;
[0007] A channel layer is located on one side of the substrate;
[0008] A composite barrier layer includes a first barrier layer, a second barrier layer, and a third barrier layer; the first barrier layer is located on the side of the channel layer away from the substrate; the second barrier layer is located on the side of the first barrier layer away from the channel layer, and the second barrier layer serves as an etch stop layer to protect the first barrier layer; the third barrier layer is located on the side of the second barrier layer away from the first barrier layer; a containment structure is provided in the central region of the third barrier layer;
[0009] The gate is located within the housing structure;
[0010] The source is located on the side of the third barrier layer away from the second barrier layer;
[0011] The drain is located on the side of the third barrier layer away from the second barrier layer.
[0012] Optionally, the second barrier layer includes an aluminum nitride second barrier layer.
[0013] Optionally, the second barrier layer includes an AlGaN second barrier layer, wherein the content of Al atoms in the AlGaN second barrier layer is greater than the content of Al atoms in the first barrier layer.
[0014] Optionally, the etching gas used to etch the containment structure includes a chlorine-based etching gas doped with oxygen (O) or fluorine (F).
[0015] Optionally, a groove is provided in the central region of the third barrier layer, and the depth of the groove is less than the thickness of the third barrier layer.
[0016] Optionally, a through-hole is provided in the central region of the third barrier layer, and the through-hole exposes the second barrier layer.
[0017] Optionally, the thickness of the second barrier layer is greater than or equal to 0.1 nm.
[0018] Optionally, the thickness of the second barrier layer is less than or equal to 3 nm.
[0019] Optionally, the bandgap width of the second barrier layer is greater than the bandgap width of the first barrier layer.
[0020] The technical solution provided in this embodiment of the invention includes a second barrier layer disposed between the first and third barrier layers. During the etching process of the third barrier layer, the second barrier layer acts as an etching barrier layer to protect the first barrier layer, thus preventing over-etching of both the second and first barrier layers. The depth of the accommodating space is less than or equal to the thickness of the third barrier layer, thereby not affecting the first barrier layer. This ensures that the two-dimensional electron gas concentration in the heterostructure of the channel layer and the first barrier layer is not affected, improving the mobility of the two-dimensional electron gas in the gallium nitride device, increasing the saturation current of the device, and thus improving the electrical performance of the gallium nitride device.
[0021] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of this utility model, nor is it intended to limit the scope of this utility model. Other features of this utility model will become readily apparent from the following description. Attached Figure Description
[0022] To more clearly illustrate the technical solutions in the embodiments of this utility model, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.
[0023] Figure 1 This is a schematic diagram of the structure of a gallium nitride device in the prior art;
[0024] Figure 2 This is a schematic diagram of another gallium nitride device provided by existing technology;
[0025] Figure 3 This is a schematic diagram of the structure of a gallium nitride device provided in an embodiment of the present invention;
[0026] Figure 4 This is a schematic diagram of another gallium nitride device provided in an embodiment of the present invention. Detailed Implementation
[0027] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.
[0028] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this utility model are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the utility model described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover a non-exclusive inclusion; for example, a process, method, system, product, or apparatus that includes a series of steps or apparatuses is not necessarily limited to those steps or apparatuses explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatuses.
[0029] As described in the background section above, in current recessed-gate enhancement-mode gallium nitride (GaN) devices, after the gate-accommodating structure is fabricated, the thickness of the barrier layer beneath the gate cannot be guaranteed, leading to poor electrical performance of the GaN device. Figure 1 As shown, Figure 1 This is a schematic diagram of a gallium nitride (GaN) device in the prior art. During the etching process of creating grooves in the barrier layer 102, although the grooves do not etch to the two-dimensional electron gas at the heterojunction of the barrier layer 102 and the channel layer 101, and a certain thickness of the barrier layer 102 is still retained, the consistency of the etching depth at the bottom of the grooves is difficult to guarantee. This can result in a low threshold voltage for the GaN device, and even make it difficult to achieve enhancement-mode GaN devices. Figure 2 As shown, Figure 2 This is a schematic diagram of another gallium nitride (GaN) device provided by existing technology. The trench completely etches the barrier layer 102, but the channel layer 101 is over-etched, resulting in very low carrier mobility below the gate 103 and a significant reduction in saturation current, severely impacting the electrical performance of the GaN device. Figure 1 and Figure 2The reference numerals in the figure are as follows: 100-substrate, 101-channel layer, 102-barrier layer, 103-gate, 104-source, 105-drain.
[0030] To solve the above-mentioned technical problems, the present invention provides the following technical solutions:
[0031] like Figure 3 As shown, Figure 3 This is a schematic diagram of a gallium nitride (GaN) device according to an embodiment of the present invention. The GaN device includes: a substrate 200; a channel layer 201 located on one side of the substrate 200; and a composite barrier layer 202, which includes a first barrier layer 2021, a second barrier layer 2022, and a third barrier layer 2023. The first barrier layer 2021 is located on the side of the channel layer 201 away from the substrate 200; and the second barrier layer 2022 is located on the side of the first barrier layer 2021 away from the channel layer 201. The second barrier layer 2022 serves as an etch barrier layer to protect the first barrier layer 2021; the third barrier layer 2023 is located on the side of the second barrier layer 2022 away from the first barrier layer 2021; a receiving structure is provided in the middle region of the third barrier layer 2023; the gate 203 is located within the receiving structure; the source 204 is located on the side of the third barrier layer 2023 away from the second barrier layer 2022; and the drain 205 is located on the side of the third barrier layer 2023 away from the second barrier layer 2022.
[0032] For example, such as Figure 2 As shown, the gallium nitride device also includes a buffer layer 206, which is used to alleviate the lattice mismatch problem between the substrate 200 and the channel layer 201. The channel layer 201 includes one or more of GaN, AlGaN, and InGaN layers.
[0033] The technical solution provided in this embodiment of the utility model includes a second barrier layer 2022 disposed between the first barrier layer 2021 and the third barrier layer 2023. During the etching process of the third barrier layer 2023, the second barrier layer 2022 acts as an etching barrier layer to protect the first barrier layer 2021, thus preventing over-etching of both the second barrier layer 2022 and the first barrier layer 2021. The depth of the accommodating space is less than or equal to the thickness of the third barrier layer 2023, thereby not affecting the first barrier layer 2021. This ensures that the two-dimensional electron gas concentration of the heterostructure of the channel layer 201 and the first barrier layer 2021 is not affected, improving the mobility of the two-dimensional electron gas in the gallium nitride device, increasing the saturation current of the device, and thus improving the electrical performance of the gallium nitride device.
[0034] Optionally, based on the above technical solution, the second barrier layer 2022 includes an aluminum nitride second barrier layer. Optionally, based on the above technical solution, the etching gas for etching the emulator structure includes a chlorine-based etching gas doped with oxygen (O) or fluorine (F).
[0035] Specifically, the second barrier layer 2022 includes an aluminum nitride second barrier layer, and the etching gas for etching the third barrier layer includes a chlorine-based etching gas doped with oxygen (O) or fluorine (F). The aluminum in the second barrier layer 2022 and the oxygen (O) in the etching gas form a dense and non-volatile Al2O3, and the aluminum in the second barrier layer 2022 and the fluorine (F) in the etching gas form a dense and non-volatile AlF3, which hinders the etching gas from etching the second barrier layer 2022. This allows the second barrier layer 2022 to act as an etching barrier layer to protect the first barrier layer 2021, thus preventing over-etching of the second barrier layer 2022 and the first barrier layer 2021.
[0036] Optionally, based on the above technical solution, the second barrier layer 2022 includes an AlGaN second barrier layer, wherein the content of Al atoms in the AlGaN second barrier layer is greater than the content of Al atoms in the first barrier layer 2021. Optionally, based on the above technical solution, the etching gas for etching the accommodating structure includes a chlorine-based etching gas doped with oxygen (O) or fluorine (F).
[0037] Specifically, the second barrier layer 2022 includes an AlGaN second barrier layer, in which the content of Al atoms is greater than that in the first barrier layer 2021. The etching gas used to etch the third barrier layer 2023 includes a chlorine-based etching gas doped with oxygen (O) or fluorine (F). The aluminum in the second barrier layer 2022 and the oxygen (O) in the etching gas form a dense and non-volatile Al2O3, and the aluminum in the second barrier layer 2022 and the fluorine (F) in the etching gas form a dense and non-volatile AlF3. This hinders the etching gas from etching the second barrier layer 2022, thus making the second barrier layer 2022 act as an etching barrier layer to protect the first barrier layer 2021. Therefore, it will not cause over-etching of the second barrier layer 2022 and the first barrier layer 2021.
[0038] Optionally, based on the above technical solutions, such as Figure 4 As shown, Figure 4 This is a schematic diagram of another gallium nitride device provided in this embodiment of the present invention. A groove is provided in the middle region of the third barrier layer 2023, and the depth of the groove is less than the thickness of the third barrier layer 2023.
[0039] The above technical solution provides that, during the etching process, the space to be accommodated is a groove, the depth of which is less than the thickness of the third barrier layer 2023. Since the second barrier layer 2022 is used as an etching barrier layer to protect the first barrier layer 2021, it will not cause over-etching of the second barrier layer 2022 and the first barrier layer 2021.
[0040] Optionally, based on the above technical solutions, such as Figure 3 As shown, a through-hole is provided in the central region of the third barrier layer 2023, exposing the second barrier layer 2022.
[0041] The above technical solution provides that, during the etching process, the space is a through hole. Even if the through hole exposes the second barrier layer 2022, since the second barrier layer 2022 is used as an etching barrier layer to protect the first barrier layer 2021, it will not cause over-etching of the second barrier layer 2022 and the first barrier layer 2021.
[0042] Optionally, based on the above technical solution, the thickness of the second barrier layer 2022 is greater than or equal to 0.1 nm and less than or equal to 3 nm. On the one hand, it can be used as an etching barrier layer to protect the first barrier layer 2021. On the other hand, it will not reduce the on-resistance of the device due to excessive thickness.
[0043] Optionally, based on the above technical solution, the bandgap of the second barrier layer 2022 is greater than the bandgap of the first barrier layer 2021.
[0044] The first barrier layer 2021 includes at least AlGaN. The fact that the bandgap of the second barrier layer 2022 is greater than that of the first barrier layer 2021 can further reduce gate leakage current and enhance device reliability. The second barrier layer 2022 is an aluminum nitride second barrier layer, or it includes an AlGaN second barrier layer. The Al atom content in the AlGaN second barrier layer is greater than that in the first barrier layer 2021, ensuring that the bandgap of the second barrier layer 2022 is greater than that of the first barrier layer 2021.
[0045] It should be understood that the various forms of the process shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this utility model can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this utility model can be achieved, and this is not limited herein.
[0046] The specific embodiments described above do not constitute a limitation on the scope of protection of this utility model. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this utility model should be included within the scope of protection of this utility model.
Claims
1. A gallium nitride device, characterized in that, include: Substrate; A channel layer is located on one side of the substrate; A composite barrier layer includes a first barrier layer, a second barrier layer, and a third barrier layer; the first barrier layer is located on the side of the channel layer away from the substrate; the second barrier layer is located on the side of the first barrier layer away from the channel layer, and the second barrier layer serves as an etch stop layer to protect the first barrier layer; the third barrier layer is located on the side of the second barrier layer away from the first barrier layer; a containment structure is provided in the central region of the third barrier layer; The gate is located within the housing structure; The source is located on the side of the third barrier layer away from the second barrier layer; The drain is located on the side of the third barrier layer away from the second barrier layer.
2. The gallium nitride device according to claim 1, characterized in that, The second barrier layer includes an aluminum nitride second barrier layer.
3. The gallium nitride device according to claim 1, characterized in that, The second barrier layer includes an AlGaN second barrier layer, wherein the content of Al atoms in the AlGaN second barrier layer is greater than the content of Al atoms in the first barrier layer.
4. The gallium nitride device according to claim 2 or 3, characterized in that, The etching gas used to etch the containment structure includes a chlorine-based etching gas doped with oxygen (O) or fluorine (F).
5. The gallium nitride device according to claim 1, characterized in that, A groove is provided in the middle region of the third barrier layer, and the depth of the groove is less than the thickness of the third barrier layer.
6. The gallium nitride device according to claim 1, characterized in that, A through-hole is provided in the central region of the third barrier layer, and the through-hole exposes the second barrier layer.
7. The gallium nitride device according to claim 1, characterized in that, The thickness of the second barrier layer is greater than or equal to 0.1 nm.
8. The gallium nitride device according to claim 7, characterized in that, The thickness of the second barrier layer is less than or equal to 3 nm.
9. The gallium nitride device according to claim 2 or 3, characterized in that, The bandgap width of the second barrier layer is greater than that of the first barrier layer.