Manufacturing method of HEMT device and HEMT device
The radio frequency loss problem of silicon-based gallium nitride radio frequency devices is solved by removing the parasitic conductive layer of the Si/AlN interface and combining the SiO2 dielectric layer with the new Si substrate by back grinding, which significantly improves performance and fabrication efficiency.
Patent Information
- Application Number
- CN202510615776.2
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-14
- Publication Date
- 2025-08-12
AI Technical Summary
The parasitic conductive layer at the Si/AlN interface in silicon-based gallium nitride radio frequency devices causes radio frequency loss problems, and the existing methods have not been effectively solved.
The parasitic conductive layer is removed by back grinding, and combined with the bonding process of the SiO2 dielectric layer and the new Si substrate, a complete device structure is formed, abandoning the traditional epitaxial suppression method.
The RF loss problem is completely solved, significantly improves device performance and improves production efficiency.
Smart Images
Figure CN120475731A_ABST
Abstract
Description
Technical Field
[0001] The present application relates to the field of semiconductor technology, and in particular to a method for manufacturing a HEMT device and a HEMT device. Background Art
[0002] GaN is currently the only material capable of simultaneously achieving high frequency, high efficiency, and high power. It is a key material supporting satellite internet, the upgrade of 5G communication base stations, the prioritized deployment of 6G communication base stations, and high-performance military radar. To further improve the performance and reduce the cost of RF GaN devices, the future development direction is to use large-scale Si-based wafers as GaN HEMT device substrates instead of SiC substrates, achieve compatibility with CMOS processes, and realize "Si-based compound" + 3D "heterogeneous integration" of multifunctional modules.
[0003] However, the RF loss problem of silicon-based gallium nitride devices is one of the issues that restricts their performance and application. The parasitic conductive layer at the AlN / Si interface is the main source of RF loss. Trapped charges introduced by doping in the buffer layer (GaN HEMT epitaxial growth requires the introduction of additional acceptor dopants such as Fe to compensate for background carriers such as Si and O in the GaN to achieve high-resistance GaN growth, but this inevitably introduces deep-level trapped charges, which capture and release carriers after being subjected to electrical stress step signals) are the main source of transient behavior leading to RF loss.
[0004] To address the aforementioned RF loss issues, existing methods include: (1) using vacancy engineering to grow a thick (7.7 μm) buffer layer during GaN epitaxy to achieve a low dislocation density and suppress RF signal coupling to the lossy Si substrate; (2) controlling the flow rate of trimethylaluminum during MOCVD growth to reduce the diffusion of Al into the Si substrate; and (3) implanting a high dose of C into the Si substrate to suppress self-interstitial-assisted Al diffusion into the Si substrate during growth. However, existing methods all focus on how to suppress Al diffusion into the Si substrate during epitaxial growth, but the parasitic conductive layer at the Si-AlN interface still exists. Summary of the Invention
[0005] In view of this, the embodiments of this specification provide a method for manufacturing a HEMT device and a HEMT device, which significantly improves device performance and enhances manufacturing efficiency by removing the parasitic conductive layer through back grinding and combining the bonding process of the SiO2 dielectric layer and the new Si substrate.
[0006] The embodiments of this specification provide the following technical solutions:
[0007] In a first aspect, an embodiment of the present specification provides a method for manufacturing a HEMT device, comprising the following steps: front-side bonding a silicon-based gallium nitride radio frequency device that has completed the front-side process; mechanically grinding the back side of the device to remove the Si substrate region containing the parasitic conductive layer; growing a SiO2 dielectric layer on the bonding surface of the new Si substrate by chemical vapor deposition, the SiO2 dielectric layer serving as a bonding medium; and combining the new Si substrate with the SiO2 dielectric layer with the ground back side of the device by a plasma activation bonding process to form a complete device structure.
[0008] In combination with the first aspect, in a possible implementation, the depth of the back grinding is controlled to stop at 2±0.5 microns from the original AlN / Si interface to completely remove the parasitic conductive layer.
[0009] In combination with the first aspect, in a possible implementation, the thickness of the SiO2 dielectric layer is 10-50 nm, which is used to relieve the lattice mismatch stress of Si-Si direct bonding and block the Al diffusion path in subsequent processes.
[0010] In combination with the first aspect, in a possible implementation, the plasma activated bonding process is performed under the conditions of a bonding temperature ≤ 200° C. and a bonding pressure range of 5-20 MPa.
[0011] In a second aspect, an embodiment of this specification provides a HEMT device, which is manufactured by the method described in any of the above solutions.
[0012] In combination with the second aspect, in a possible implementation, the back side of the device has a new Si substrate with the parasitic conductive layer completely removed, and a SiO2 dielectric layer is provided between the new Si substrate and the original device.
[0013] In combination with the second aspect, in a possible implementation, the SiO 2 dielectric layer is formed by chemical vapor deposition.
[0014] In combination with the second aspect, in a possible implementation, the thickness of the SiO2 dielectric layer is 10-50 nm, which is used to relieve lattice mismatch stress and block the Al diffusion path.
[0015] In combination with the second aspect, in a possible implementation, the device is prepared by a plasma activated bonding process, wherein the bonding temperature is ≤200° C. and the bonding pressure ranges from 5 MPa to 20 MPa.
[0016] Compared with the prior art, the at least one technical solution adopted in the embodiments of this specification can achieve the following beneficial effects:
[0017] This application performs front-side bonding on a silicon-based gallium nitride RF device that has completed the front-side process; then mechanically grinds the back of the device to remove the Si substrate area containing the parasitic conductive layer; and grows a SiO2 dielectric layer on the bonding surface of the new Si substrate by chemical vapor deposition; finally, the new Si substrate with the SiO2 dielectric layer is combined with the grinded back of the device through a plasma activation bonding process to form a complete device structure. By using the "physical removal of the parasitic conductive layer + dielectric bonding interface + substrate reconstruction" method, the traditional epitaxial suppression method is abandoned, and the RF loss problem caused by the parasitic conductive layer at the Si / AlN interface in silicon-based gallium nitride RF devices is completely solved, significantly improving device performance and increasing manufacturing efficiency. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] Figure 1 is a flow chart of a method for manufacturing a HEMT device provided in this application;
[0019] Figure 2 This is a schematic structural diagram of the front-side process of the silicon-based gallium nitride radio frequency device provided by this application;
[0020] Figure 3 This is a schematic diagram of the structure of the silicon-based gallium nitride radio frequency device provided by this application after front-side bonding is completed;
[0021] Figure 4 This is a schematic diagram of the structure of the silicon-based gallium nitride radio frequency device provided by this application after back grinding;
[0022] Figure 5 This is a schematic structural diagram of a HEMT device obtained by bonding the silicon-based gallium nitride radio frequency device provided by the present application to a new Si substrate;
[0023] Figure 6 This is a schematic diagram of the structure of the HEMT device provided in this application after the Si substrate is thinned;
[0024] Figure 7 This is a schematic diagram of the structure of the HEMT device provided in this application after front-side debonding. DETAILED DESCRIPTION
[0025] The embodiments of the present application are described in detail below with reference to the accompanying drawings.
[0026] The following describes the embodiments of the present application through specific examples, and those skilled in the art can easily understand other advantages and effects of the present application from the contents disclosed in this specification. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. The present application can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present application. It should be noted that, in the absence of conflict, the features in the following embodiments and embodiments can be combined with each other. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without making creative work are within the scope of protection of this application.
[0027] It should be noted that various aspects of the embodiments within the scope of the appended claims are described below. It should be apparent that the aspects described herein can be embodied in a wide variety of forms, and any specific structure and / or function described herein is merely illustrative. Based on this application, it should be understood by those skilled in the art that an aspect described herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number and aspect described herein can be used to implement an apparatus and / or practice a method. In addition, other structures and / or functionalities other than one or more of the aspects described herein can be used to implement this apparatus and / or practice this method.
[0028] It should also be noted that the illustrations provided in the following embodiments are only schematic illustrations of the basic concept of the present application. The illustrations only show components related to the present application and are not drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component can be changed at will, and the component layout type may also be more complicated.
[0029] The following describes the technical solutions provided by various embodiments of the present application in conjunction with the accompanying drawings.
[0030] like Figure 1 As shown, the embodiment of this specification provides a method for manufacturing a HEMT device, including S101-S104.
[0031] Step S101: performing front-side bonding on the GaN-on-Si radio frequency device that has completed the front-side process.
[0032] Step S102 : mechanically grinding the back side of the device to remove the Si substrate region containing the parasitic conductive layer.
[0033] Step S103: A SiO2 dielectric layer is grown on the bonding surface of the new Si substrate by chemical vapor deposition (CVD). The SiO2 dielectric layer serves as a bonding medium. It should be noted that the new Si substrate is pre-prepared, and step S103 is then performed on the pre-prepared new Si substrate.
[0034] Step S104: combining the new Si substrate with the SiO2 dielectric layer with the ground back surface of the device through a plasma activated bonding process to form a complete device structure.
[0035] In combination with the above steps, the manufacturing method of the HEMT device of this embodiment is to perform front-side bonding on the silicon-based gallium nitride RF device that has completed the front-side process; then mechanically grind the back of the device to remove the Si substrate area containing the parasitic conductive layer; and grow a layer of SiO2 dielectric layer on the bonding surface of the new Si substrate by chemical vapor deposition; finally, the new Si substrate with the SiO2 dielectric layer is combined with the back of the ground device through a plasma activation bonding process to form a complete device structure. By "physical removal of parasitic conductive layer + dielectric bonding interface + substrate reconstruction", the traditional epitaxial suppression method is abandoned, and the RF loss problem caused by the parasitic conductive layer at the Si / AlN interface in the silicon-based gallium nitride RF device is completely solved, significantly improving device performance and enhancing manufacturing efficiency.
[0036] In a preferred embodiment, when performing step S102 , the back grinding depth is controlled to stop at 2±0.5 μm from the original AlN / Si interface to ensure that the Si substrate region containing the parasitic conductive layer is completely removed.
[0037] In a preferred embodiment, when performing step S103, the thickness of the SiO2 dielectric layer is 10-50 nm. This layer serves as a bonding medium to relieve the lattice mismatch stress of Si-Si direct bonding and block the Al diffusion path in subsequent processes.
[0038] In a preferred embodiment, when performing step S104 , the plasma activation bonding process is performed under the conditions of a bonding temperature of ≤ 200° C. and a bonding pressure range of 5-20 MPa.
[0039] The steps of the above embodiment are described in conjunction with the structural diagram of the silicon-based gallium nitride radio frequency device.
[0040] like Figure 2 As shown in FIG. 1 , the structure of the silicon-based gallium nitride radio frequency device after the front process is completed is obtained by performing the front bonding process of step S101. Figure 3 Silicon-based gallium nitride RF device with the structure shown.
[0041] Further, the back grinding process of step S102 is performed to obtain Figure 4Silicon-based gallium nitride RF device with the structure shown.
[0042] Further, step S103 is performed to deposit a SiO2 dielectric layer on the bonding surface of the new Si substrate.
[0043] Then, the bonding process of the new Si substrate and the back-ground silicon-based gallium nitride radio frequency device in step S104 is performed to obtain the following Figure 5 The complete HEMT device structure is shown.
[0044] The manufacturing method of the above embodiment is carried out after the front surface process of the conventional silicon-based gallium nitride radio frequency device is completed and before the back substrate is thinned. That is, after obtaining Figure 5 After the HEMT device structure is completed, the following steps can be performed: Figure 6 The structure shown corresponds to the back side new Si substrate thinning process and Figure 7 The structure shown corresponds to the front-side debonding process of the HEMT device.
[0045] The embodiments of this specification also provide a HEMT device, which is manufactured using the method of the above embodiments.
[0046] That is, the back of the HEMT device has a new Si substrate with the parasitic conductive layer completely removed, and a SiO2 dielectric layer is provided between the new Si substrate and the original device. Moreover, the SiO2 dielectric layer is deposited by chemical vapor deposition, with a thickness of 10-50nm, which is used to relieve lattice mismatch stress and block the Al diffusion path. The device is prepared by a plasma activated bonding process, where the bonding temperature is ≤200°C and the bonding pressure range is 5-20MPa.
[0047] The fabrication method and the HEMT device fabricated in the above embodiments have the following advantages:
[0048] 1. Parasitic layer elimination mechanism: By physically removing the original Si substrate area containing the parasitic conductive layer, rather than relying on traditional epitaxial suppression methods, the root cause of RF loss is completely solved.
[0049] 2. Dynamic resistance control: The newly bonded Si substrate is free of doping pollution, and the interface SiO2 layer design blocks the residual Al diffusion path and stabilizes the resistivity characteristics.
[0050] 3. Process compatibility: It is implemented after the front-side process is completed to avoid interference with the quality of the epitaxial layer and is suitable for large-scale mass production.
[0051] The same or similar parts between the various embodiments in this specification can be referred to in conjunction with each other. Each embodiment focuses on the differences from other embodiments. In particular, for the product embodiments described later, since they correspond to the methods, the description is relatively simple. For relevant parts, please refer to the partial description of the system embodiment.
[0052] The above description is merely a specific embodiment of the present application, but the scope of protection of the present application is not limited thereto. Any changes or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present application should be included in the scope of protection of the present application. Therefore, the scope of protection of the present application should be based on the scope of protection of the claims.
Claims
1. A method for manufacturing a HEMT device, characterized in that: The following steps are involved: Perform front-side bonding on GaN-on-Si RF devices that have completed the front-side process; Mechanically grinding the back of the device to remove the Si substrate region containing the parasitic conductive layer; Growing a SiO2 dielectric layer on the bonding surface of the new Si substrate by chemical vapor deposition, wherein the SiO2 dielectric layer serves as a bonding medium; The new Si substrate with the SiO2 dielectric layer is bonded to the ground back surface of the device through a plasma activated bonding process to form a complete device structure.
2. The production method according to claim 1, characterized in that: The depth of the backside grinding is controlled to stop at 2±0.5 μm from the original AlN / Si interface to completely remove the parasitic conductive layer.
3. The production method according to claim 1, characterized in that: The thickness of the SiO2 dielectric layer is 10-50 nm, and is used to relieve the lattice mismatch stress of Si-Si direct bonding and block the Al diffusion path in subsequent processes.
4. The production method according to claim 1, wherein: The plasma activated bonding process is carried out under the conditions of a bonding temperature of ≤200° C. and a bonding pressure range of 5-20 MPa.
5. A HEMT device, characterized in that: The device is manufactured by the method according to any one of claims 1 to 4.
6. The HEMT device according to claim 5, wherein: The back side of the device has a new Si substrate with the parasitic conductive layer completely removed, and a SiO2 dielectric layer is provided between the new Si substrate and the original device.
7. The HEMT device according to claim 6, wherein: The SiO2 dielectric layer is deposited by chemical vapor deposition.
8. The HEMT device according to claim 6, wherein: The thickness of the SiO2 dielectric layer is 10-50 nm, and is used to relieve lattice mismatch stress and block the Al diffusion path.
9. The HEMT device according to claim 5, wherein: The device is prepared by a plasma activated bonding process, wherein the bonding temperature is ≤ 200° C. and the bonding pressure ranges from 5 to 20 MPa.