CN118116967A

CN118116967A - Radio frequency device, preparation method thereof and electronic equipment

Info

Publication number: CN118116967A
Application number: CN202211521778.8A
Authority: CN
Inventors: 李水明; 何涛; 李海军
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2022-11-30
Filing date: 2022-11-30
Publication date: 2024-05-31
Also published as: WO2024113863A1

Abstract

The embodiment of the application provides a radio frequency device, a preparation method thereof and electronic equipment, and relates to the technical field of semiconductors. The radio frequency device comprises a substrate, a circuit structure, a first dielectric layer, an auxiliary electrode and a second dielectric layer. The circuit structure is located on one side of the substrate, and the circuit structure comprises a first surface far away from the substrate, wherein the first surface comprises a step surface, and the step surface comprises a protrusion far away from one side of the substrate. The first dielectric layer is positioned on one side of the first surface away from the substrate. The first dielectric layer includes a second surface remote from the substrate. The difference in distance from any two points in the second surface to the upper surface of the substrate in the direction perpendicular to the substrate is less than or equal to 20nm. The auxiliary electrode comprises a first sub-electrode and a second sub-electrode which are connected. The second dielectric layer is positioned on one side of the first dielectric layer away from the substrate and covers the auxiliary electrode. The radio frequency device is used for improving the moisture-proof and waterproof characteristics of the device and improving the reliability of the device. The radio frequency device is applied to the electronic equipment to improve the performance of the electronic equipment.

Description

Radio frequency device, preparation method thereof and electronic equipment

Technical Field

The present application relates to the field of semiconductor technologies, and in particular, to a radio frequency device, a method for manufacturing the same, and an electronic apparatus.

Background

With the development of semiconductor technology, the requirements for device performance are continuously increased, so that the appearance of novel semiconductor materials and devices is promoted. Gallium arsenide (GaAs), gallium nitride (GaN) and other materials have the characteristics of high electron drift rate, high temperature resistance, stable chemical properties and the like, and are widely applied to the fields of high frequency, high temperature and microwaves.

Currently, gaN and GaAs devices mostly use heterojunction as a basic structure. A high electron mobility transistor (high electron mobility transistor, HEMT) is a semiconductor device that utilizes a high concentration of two-dimensional electron gas (two dimensional electron gas,2 DEG) generated at the heterojunction location as a current carrier. The 2DEG achieves separation of impurities from electrons in the spatial dimension, avoids or reduces impurity scattering, and therefore electrons have higher mobility. The basis of the GaN radio frequency device is HEMT.

With the continuous development of the third generation semiconductor technology, more and more application scenes select GaN radio frequency devices, and the GaN HEMT radio frequency devices are continuously penetrated and used in a large scale under different scenes. Based on this, the field puts strict requirements on the moisture resistance and robustness of the GaN HEMT radio frequency device.

Disclosure of Invention

The embodiment of the application provides a radio frequency device, a preparation method thereof and electronic equipment, which are used for improving the moisture-proof and waterproof characteristics of the device and improving the reliability of the device.

In order to achieve the above purpose, the embodiment of the present application adopts the following technical scheme:

In a first aspect, a radio frequency device is provided that includes a substrate, a circuit structure, a first dielectric layer, an auxiliary electrode, and a second dielectric layer. The circuit structure is located on one side of the substrate, and comprises a first surface far away from the substrate, wherein the first surface comprises a step surface, and the step surface comprises a protrusion far away from one side of the substrate. The first dielectric layer is positioned on one side of the first surface away from the substrate. The first dielectric layer includes a second surface remote from the substrate. In a direction perpendicular to the substrate, a difference between distances from any two points in the second surface to an upper surface of the substrate is less than or equal to 20nm. The auxiliary electrode comprises a first sub-electrode and a second sub-electrode which are connected, the first sub-electrode is positioned on one side, far away from the substrate, of the first dielectric layer, and the second sub-electrode penetrates through the first dielectric layer and is connected with the circuit structure. And the second dielectric layer is positioned on one side of the first dielectric layer away from the substrate and covers the auxiliary electrode.

The radio frequency device provided by the embodiment of the application comprises the first dielectric layer and the second dielectric layer positioned on one side of the first dielectric layer far away from the substrate, wherein the difference between the distances from any two points in the second surface of the first dielectric layer to the upper surface of the substrate is smaller than or equal to 20nm in the direction perpendicular to the substrate, so that the whole second surface is flat. Thus, even if a merging gap is generated in the part of the first dielectric layer, which is positioned on the step surface, in the process of forming the first dielectric layer, the part of the second dielectric layer, which is positioned on one side of the step surface, which is far away from the substrate, is not provided with the merging gap, the merging gap in the first dielectric layer cannot pass through the second dielectric layer to be communicated with the outside, so that water vapor in the outside environment cannot easily enter the merging gap of the first dielectric layer and enter the circuit structure through the merging gap, the problem that the first dielectric layer is cracked due to invasion of water vapor is avoided, the problem that the water vapor contacts with electrodes in the circuit structure is avoided, the electrodes are corroded, the problem of mutual short circuit between electrodes on the same layer is caused, the dampproof and waterproof characteristics of the radio frequency device are improved, and meanwhile, the reliability of the radio frequency device is improved.

In some embodiments, the second surface is parallel to an upper surface of the substrate. At this time, the portion of the second surface located on the step surface is flatter. Like this, the second dielectric layer that is located one side that the substrate was kept away from to first dielectric layer can not produce the merge gap in the position department that corresponds the step face more for the steam in the external environment is difficult to pass first dielectric layer and second dielectric layer more and enters into circuit structure, thereby has further improved the dampproofing waterproof characteristic of radio frequency device, has improved the reliability of radio frequency device.

In some embodiments, the portion of the second surface covered by the first sub-electrode is a first portion, and the portion of the second surface surrounding the first sub-electrode is a second portion, the first portion being further from the upper surface of the substrate than the second portion.

In some embodiments, the radio frequency device further comprises a third dielectric layer located between the first dielectric layer and the first sub-electrode; the second sub-electrode also penetrates through the third dielectric layer. In the embodiment of the application, the part of the second surface positioned on the step surface is relatively flat, so that a merging gap does not appear in the part of the third dielectric layer positioned on the side of the step surface away from the substrate. Thus, even if the first dielectric layer is positioned on the step surface, the merging gap is formed in the second dielectric layer, and the third dielectric layer can separate the merging gap in the first dielectric layer from the merging gap in the second dielectric layer, so that the merging gap in the first dielectric layer is further prevented from being communicated with the external environment, the invasion of water vapor is further blocked, the moisture-proof and water-proof characteristics of the radio frequency device are improved, and the reliability of the radio frequency device is improved.

In some embodiments, the third dielectric layer includes a third surface remote from the substrate, the portion of the third surface covered by the first sub-electrode being a third portion, the portion of the third surface surrounding the first sub-electrode being a fourth portion, the third portion being further from the upper surface of the substrate than the fourth portion.

In some embodiments, the third dielectric layer includes a third surface remote from the substrate, the third surface being parallel to the upper surface of the substrate.

In some embodiments, the circuit structure includes a heterojunction, a fourth dielectric layer, a source electrode, a drain electrode, a fifth dielectric layer, and a gate electrode. The heterojunction is positioned on one side of the substrate; the heterojunction includes a channel layer and a barrier layer sequentially stacked in a direction away from the substrate. The fourth dielectric layer is positioned on one side of the heterojunction away from the substrate. The source electrode and the drain electrode are positioned on one side, far away from the substrate, of the fourth dielectric layer, and the source electrode and the drain electrode penetrate through the fourth dielectric layer to be in contact with the barrier layer. And a fifth dielectric layer is positioned on one side of the fourth dielectric layer away from the substrate, and the fifth dielectric layer covers the source electrode and the drain electrode. The grid electrode is positioned on one side of the fifth dielectric layer away from the substrate and is positioned between the source electrode and the drain electrode; and the grid penetrates through the fourth dielectric layer and the fifth dielectric layer and is in contact with the barrier layer.

In some embodiments, the circuit structure further includes a sixth dielectric layer and a field plate electrode. And the sixth dielectric layer is positioned on one side of the fifth dielectric layer far away from the substrate, and the sixth dielectric layer covers the grid electrode. The field plate electrode is positioned on one side of the sixth dielectric layer far away from the substrate, and the orthographic projection of the field plate electrode on the substrate is overlapped with the orthographic projection part of the grid electrode on the substrate.

Therefore, the electric field distribution in the radio frequency device can be adjusted, so that the electric field distribution at the position of the edge of the grid electrode is more uniform, the electric field peak is avoided, and the breakdown resistance of the radio frequency device is improved.

In some embodiments, the radio frequency device includes an active region and a passive region surrounding the active region. The radio frequency device further includes a first liner, a second liner, and a third liner; the first liner and the second liner are positioned on one side of the first dielectric layer away from the substrate; the first pad and the second pad are located in the inactive region, and the first pad and the second pad are electrically connected to the drain electrode and the gate electrode through the auxiliary electrode, respectively. The third pad is positioned on one side of the substrate away from the circuit structure; the third pad is electrically connected with the source electrode.

In some embodiments, a portion of the second dielectric layer on a side of the step surface away from the substrate does not have a merge gap.

In a second aspect, a method for manufacturing a radio frequency device is provided, including: a circuit structure is formed on a side of a substrate, the circuit structure including a first surface remote from the substrate, the first surface including a step surface including a protrusion remote from the side of the substrate. Forming a first dielectric layer on one side of the circuit structure away from the substrate; the first dielectric layer includes a second surface remote from the substrate, the second surface having a height that varies with the height of the first surface. And carrying out planarization treatment on the second surface of the first dielectric layer. And forming an auxiliary electrode, wherein the auxiliary electrode comprises a first sub-electrode and a second sub-electrode which are connected, the first sub-electrode is positioned on one side of the first dielectric layer far away from the substrate, and the second sub-electrode penetrates through the first dielectric layer and is connected with the circuit structure. And forming a second dielectric layer on one side of the first dielectric layer far away from the substrate, wherein the second dielectric layer covers the auxiliary electrode. After the second surface of the first dielectric layer is subjected to planarization treatment, the difference between the distances from any two points in the second surface to the upper surface of the substrate in the direction perpendicular to the substrate is less than or equal to 20nm.

In the method for manufacturing the radio frequency device provided by the embodiment of the application, the first dielectric layer is formed on the first surface with the rugged surface, the second surface of the first dielectric layer is rugged, and the second surface of the first dielectric layer is subjected to planarization treatment, so that the second surface of the first dielectric layer is relatively flat. Thus, even if the first dielectric layer generates a merging gap at the step surface corresponding to the first surface in the forming process, after the second dielectric layer is formed on the flat second surface, the merging gap cannot be formed in the part, which is positioned on one side of the step surface, far away from the substrate, of the second dielectric layer, the merging gap in the first dielectric layer cannot penetrate through the second dielectric layer to be communicated with the outside, so that water vapor in the outside environment cannot easily enter the merging gap of the first dielectric layer and enter the circuit structure through the merging gap, the problem that the first dielectric layer is cracked due to invasion of water vapor is avoided, the problem that the water vapor contacts electrodes in the circuit structure to cause corrosion of the electrodes at the same layer to cause mutual short circuit is avoided, the moisture-proof and waterproof characteristics of the radio frequency device are improved, and meanwhile, the reliability of the radio frequency device is improved.

In some embodiments, the planarizing the second surface of the first dielectric layer includes: and removing part of the first dielectric layer by adopting a chemical mechanical polishing process or a dry etching process so as to flatten the second surface of the first dielectric layer.

In some embodiments, the planarizing the second surface of the first dielectric layer includes: forming a sacrificial layer on one side of the first dielectric layer away from the substrate; the sacrificial layer includes a fourth surface remote from the substrate, the fourth surface having a height that varies with the second surface. And removing at least part of the sacrificial layer by adopting a dry etching process so as to flatten the second surface of the first dielectric layer.

In some embodiments, the material of the sacrificial layer comprises an organic material.

In some embodiments, the forming the auxiliary electrode includes: and etching the first dielectric layer to form an opening, wherein the opening exposes the source electrode, the drain electrode or the grid electrode in the circuit structure. And forming a conductive layer on one side of the first dielectric layer away from the substrate. Etching the conductive layer to form an auxiliary electrode; the auxiliary electrode comprises a first sub-electrode positioned on the second surface and a second sub-electrode positioned in the opening; the second sub-electrode is electrically connected to the source electrode, the drain electrode, or the gate electrode.

In some embodiments, the forming the auxiliary electrode includes: and etching the first dielectric layer to form an opening, wherein the opening exposes the source electrode, the drain electrode or the grid electrode in the circuit structure. And forming a conductive layer on one side of the first dielectric layer away from the substrate. Removing part of the conductive layer by adopting a stripping process to form an auxiliary electrode; the auxiliary electrode comprises a first sub-electrode positioned on the second surface and a second sub-electrode positioned in the opening; the second sub-electrode is electrically connected to the source electrode, the drain electrode, or the gate electrode.

In some embodiments, after the planarizing the second surface of the first dielectric layer, before the forming the auxiliary electrode, the preparation method further includes: and forming a third dielectric layer on one side of the first dielectric layer away from the substrate. Wherein the second portion also extends through the third dielectric layer.

In some embodiments, the thickness of the first dielectric layer is 400nm to 5 μm before the planarization treatment is performed on the second surface of the first dielectric layer.

In a third aspect, an electronic device is provided, including a circuit board, a radio frequency device as in any of the embodiments above, the radio frequency device being electrically connected to the circuit board.

The technical effects caused by any one of the design manners in the third aspect may be referred to the technical effects caused by the different design manners in the first aspect, which are not described herein.

Drawings

In order to more clearly illustrate the technical solutions of the present application, the drawings that are required to be used in some embodiments of the present application will be briefly described below, and it is apparent that the drawings in the following description are only drawings of some embodiments of the present application, and other drawings may be obtained according to these drawings to those of ordinary skill in the art. Furthermore, the drawings in the following description may be regarded as schematic diagrams, not limiting the actual size of the product, the actual flow of the method, the actual timing of the signals, etc. according to the embodiments of the present application.

Fig. 1 is a schematic structural diagram of an electronic device according to an embodiment of the present application;

Fig. 2 is a schematic structural diagram of another electronic device according to an embodiment of the present application;

Fig. 3 is a schematic structural diagram of still another electronic device according to an embodiment of the present application;

fig. 4 is a schematic structural diagram of a radio frequency device according to an embodiment of the present application;

fig. 5 is a schematic structural diagram of another radio frequency device according to an embodiment of the present application;

fig. 6 is a schematic structural diagram of another radio frequency device according to an embodiment of the present application;

fig. 7 is a schematic structural diagram of another radio frequency device according to an embodiment of the present application;

Fig. 8 is a schematic structural diagram of another radio frequency device according to an embodiment of the present application;

Fig. 9 is a schematic structural diagram of another radio frequency device according to an embodiment of the present application;

Fig. 10 is a schematic structural diagram of another radio frequency device according to an embodiment of the present application;

Fig. 11 is a schematic structural diagram of another radio frequency device according to an embodiment of the present application;

Fig. 12 is a schematic structural diagram of another radio frequency device according to an embodiment of the present application;

fig. 13 is a flowchart of a method for manufacturing a radio frequency device according to an embodiment of the present application;

Fig. 14 to 17B are state diagrams of the radio frequency device corresponding to the preparation method provided in fig. 13;

Fig. 18A is a flowchart of another method for manufacturing a radio frequency device according to an embodiment of the present application;

fig. 18B is a flowchart of a method for manufacturing a radio frequency device according to another embodiment of the present application;

Fig. 19 is a state diagram of a radio frequency device corresponding to the preparation method provided in fig. 18B;

fig. 20 is a flowchart of a method for manufacturing a radio frequency device according to another embodiment of the present application;

fig. 21 and 22 are state diagrams of the radio frequency device corresponding to the preparation method provided in fig. 20;

fig. 23 is a flowchart of a method for manufacturing a radio frequency device according to another embodiment of the present application;

Fig. 24 is a flowchart of a method for manufacturing a radio frequency device according to another embodiment of the present application;

Fig. 25A and 25B are state diagrams of the radio frequency device corresponding to the preparation method provided in fig. 24.

Detailed Description

The technical solutions in the embodiments of the present application will be described below with reference to the accompanying drawings in the embodiments of the present application. Wherein, in the description of the present application, "/" means that the related objects are in a "or" relationship, for example, a/B may mean a or B, unless otherwise specified.

The "and/or" in the present application is merely an association relationship describing the association object, and indicates that three relationships may exist, for example, a and/or B may indicate: there are three cases, a alone, a and B together, and B alone, wherein a, B may be singular or plural.

In the description of the present application, unless otherwise indicated, "a plurality" means two or more than two. "at least one of" or the like means any combination of these items, including any combination of single item(s) or plural items(s). For example, at least one (one) of a, b, or c may represent: a, b, c, a and b, a and c, b and c, or a and b and c, wherein a, b, c may be single or plural.

In order to clearly describe the technical solution of the embodiments of the present application, in the embodiments of the present application, the words "first", "second", etc. are used to distinguish the same item or similar items having substantially the same function and effect. It will be appreciated by those of skill in the art that the words "first," "second," and the like do not limit the amount and order of execution, and that the words "first," "second," and the like do not necessarily differ.

In embodiments of the application, words such as "exemplary" or "such as" are used to mean serving as an example, instance, or illustration. Any embodiment or design described herein as "exemplary" or "e.g." in an embodiment should not be taken as preferred or advantageous over other embodiments or designs. Rather, the use of words such as "exemplary" or "such as" is intended to present related concepts in a concrete fashion that may be readily understood.

Embodiments of the present application provide an electronic device that may include a communication device (e.g., a base station, a cell phone), a wireless charging device, a medical device, a radar, a navigation device, a Radio Frequency (RF) plasma lighting device, an RF induction and microwave heating device, and so forth. The embodiment of the application does not limit the specific form of the electronic device.

Taking a base station as an example, fig. 1 shows a simple structure of a base station 100, the base station 100 comprises a control unit 101, the control unit 101 in the base station 100 comprises a wireless transceiver, an antenna and related signal processing circuits, etc., wherein the control unit 101 mainly comprises four components: cell controllers, voice channel controllers, signaling channel controllers, and multi-way interfaces for expansion. The control unit 101 of one base station 100 generally controls several base transceiver stations, and the control unit 101 of the base station 100 is responsible for all mobile communication interface management, mainly allocation, release, management of radio channels, etc., by remote commands of the transceiver stations and the mobile stations.

With continued reference to fig. 1, the base station 100 further includes a transmission unit 102, where the transmission unit 102 is connected to a core network, and control signaling, voice call or data service information on the core network side is sent to the control unit 101 of the base station 100 through the transmission unit 102, and these services are processed by the control unit 101.

Referring to fig. 1 again, the base station 100 further includes a baseband unit 103, an RF unit 104, and a Power Amplifier (PA) 105, where the baseband unit 103 mainly performs functions such as baseband modulation and demodulation, radio resource allocation, call processing, power control, and soft handoff. The RF unit 104 mainly performs conversion between an air radio frequency channel and a baseband digital channel, amplifies signals by the PA105, transmits the amplified signals to an antenna through a radio frequency feeder line, and receives radio waves transmitted by the antenna through a wireless channel by a terminal device, such as a mobile phone (mobile phone), a tablet personal computer (pad), and demodulates signals belonging to the terminal device. The main function of PA is to amplify radio frequency signals.

With continued reference to fig. 1, the base station further includes a power supply unit 106, where the power supply unit 106 may be configured to supply power to the control unit 101, the transmission unit 102, the baseband unit 103, and so on.

Fig. 2 shows a block diagram of another electronic device, such as a mobile phone, where the mobile phone 200 may include a center 201, a rear case 202, and a display 203. The middle frame 201 includes a carrying board 2011 for carrying the display 203, and a frame 2012 surrounding the carrying board 2011 for a circle, wherein the carrying board 2011 carries an RF unit and a PA device, and the PA device amplifies a signal output by the RF unit and feeds the amplified signal to an antenna in the mobile phone (for example, the antenna may be disposed along an edge of the frame 2012) to send and receive the signal.

In some embodiments, a device formed of Laterally Diffused Metal Oxide Semiconductor (LDMOS) may be employed as PA, or a device formed of gallium arsenide (GaAs) may be employed as PA.

With the development of the fourth generation mobile communication technology (4rd generation of wireless communications technologies,4G) to the fifth generation mobile communication technology (5rd generation of wireless communications technologies,5G), the requirement for the function of amplifying radio frequency signals of the PA is also increasing, for example, compared with the 4G network communication, the communication band of 5G is shifted to a high frequency band, for example, to 3GHz to 5 GHz.

Gallium arsenide (GaAs) devices, however, have the significant disadvantage of lower power (e.g., power typically below 50W) and LDMOS devices have the significant disadvantage of limited operating frequencies (operating frequencies typically below 3 GHz). Gallium arsenide (GaAs) devices and LDMOS have therefore failed to meet the 5G communication network requirements.

The gallium nitride (GaN) radio frequency device combines the power processing capability of the LDMOS device while reflecting the high-frequency performance of the gallium arsenide device, and can meet the requirements of 5G on high communication frequency bands, high power and the like, so that the application range of the gallium nitride (GaN) radio frequency device is wider and wider.

As shown in fig. 3, in some examples, a radio frequency device 300 (e.g., a power amplifier) may be carried on a package substrate 400 and disposed on the package substrate 400 by an electrical connection structure (e.g., a metal layer) 401 so that the radio frequency device 300 may be signal interconnected with other electronic devices on the package substrate 400. The package substrate 400 is further disposed on the circuit board 500, such as a printed circuit board (printed circuit board, PCB), by another electrical connection structure 402, where the other electrical connection structure 402 may be a ball grid array (ball GRID ARRAY, BGA) or other electrical connection structure.

In other examples, the radio frequency device 300 in the electronic apparatus may be disposed directly on the circuit board 500 and electrically connected to the circuit board 500.

The inventor of the application finds that in the preparation process of the radio frequency device, a dielectric layer is often used for protecting the device from the influence of water vapor in the air, but the dielectric layer is discontinuous when being deposited on different planes due to the existence of a front layer relief structure, and the dielectric layers of different planes are intersected at steps, so that a merging gap is easy to appear in the dielectric layer, and the merging gap becomes a weak path for the invasion of the water vapor, thereby causing the failure of the device.

The merging slit is understood as an interface in the dielectric layer, which extends from a surface of the dielectric layer close to the substrate to a surface of the dielectric layer far from the substrate, and divides the dielectric layer into two adjacent parts. Or a merge gap may also be understood as a defect in the dielectric layer.

Based on this, as shown in fig. 4 to 6, an embodiment of the present application provides a radio frequency device 300, where the radio frequency device 300 includes a substrate 10, a circuit structure 20, a first dielectric layer 30, an auxiliary electrode 40, and a second dielectric layer 50.

In some examples, the material of the substrate 10 may include silicon carbide (SiC), silicon (Si), sapphire, diamond, and the like.

The circuit structure 20 is located on one side of the substrate 10, the circuit structure 20 comprising a first surface S1 remote from the substrate 10, the first surface S1 comprising a step surface S11, the step surface S11 comprising a protrusion remote from the side of the substrate 10. In fig. 4 to 6, the first surface S1 is shown by a "black thick solid line", and the step surface S11 is circled by a "black dotted line frame".

In some examples, the first surface S1 may include a plurality of stepped surfaces S11. For example, as shown in fig. 4 to 6, the first surface S1 may include a plurality of step surfaces S11 in a first direction X parallel to the substrate 10.

It will be appreciated that when the circuit configuration 20 of the rf device 300 is different, the number and configuration of the step surfaces S11 are also different. Possible structures of the circuit structure 20 are described in the following embodiments, and are not described here again.

As shown in fig. 4,5 and 6, the first dielectric layer 30 is located on a side of the first surface S1 remote from the substrate 10. The first dielectric layer 30 includes a second surface S2 remote from the substrate 10. The difference in distance from any two points in the second surface S2 to the upper surface S0 of the substrate 10 in the direction perpendicular to the substrate 10 (i.e., the second direction Y) is less than or equal to 20nm.

"The difference between the distances from any two points in the second surface S2 to the upper surface S0 of the substrate 10 in the direction perpendicular to the substrate 10 is less than or equal to 20nm", it may be that the difference between the distances from any two points in the second surface S2 to the upper surface S0 of the substrate 10 in the direction perpendicular to the substrate 10 is equal to zero. For example, referring to fig. 4, the second surface S2 has any two points, such as a point N1 and a point N2, where a distance from the point N1 to the upper surface S0 of the substrate 10 is h1, a distance from the point N2 to the upper surface S0 of the substrate 10 is h2, and h1 is equal to h2 in a direction perpendicular to the substrate 10.

Or "the difference between the distances from any two points in the second surface S2 to the upper surface S0 of the substrate 10 in the direction perpendicular to the substrate 10 is less than or equal to 20nm" may be that the difference h1 between the distances from any two points in the second surface S2 to the upper surface S0 of the substrate 10 in the direction perpendicular to the substrate 10 is greater than zero and less than or equal to 20nm. For example, referring to fig. 5 and 6, the second surface S2 has any two points, such as a point N3 and a point N4, wherein a distance from the point N3 to the upper surface S0 of the substrate 10 is h3, a distance from the point N4 to the upper surface S0 of the substrate 10 is h4, h3 is less than h4, and a difference between h4 and h3 is less than 20nm in a direction perpendicular to the substrate 10.

Illustratively, the difference in distance from any two points in the second surface S2 to the upper surface S0 of the substrate 10 in the direction perpendicular to the substrate 10 may be 0nm, 1nm, 5nm, 10nm, 15nm, or 20nm. The difference between the distances from any two points in the second surface S2 to the upper surface S0 of the substrate 10 in the embodiment of the present application is not limited thereto, as long as it is less than or equal to 20nm.

Illustratively, the material of the first dielectric layer 30 may include an insulating medium such as silicon nitride, silicon oxide, aluminum oxide, and the like.

The thickness d1 of the first dielectric layer 30 may be 10nm to 5 μm, for example. For example, the thickness d1 of the first dielectric layer 30 may be 10nm, 100nm, 500nm, 1 μm, 2 μm, 4 μm, 5 μm, or the like.

In this way, on the one hand, the occurrence of the condition that the circuit structure cannot be normally protected due to the small thickness of the first dielectric layer 30 can be avoided, and on the other hand, the problem of high cost due to the large thickness of the first dielectric layer 30 can be avoided.

In some examples, the first dielectric layer 30 may be prepared using a Plasma Chemical Vapor Deposition (PCVD), atomic layer deposition (atomic layer deposition, ALD), low pressure chemical vapor deposition (low pressure chemical vapor deposition, LPVD), or the like.

The auxiliary electrode 40 includes a first sub-electrode 41 and a second sub-electrode 42, wherein the first sub-electrode 41 is located on a side of the first dielectric layer 30 away from the substrate 10, and the second sub-electrode 42 penetrates through the first dielectric layer 30 to be electrically connected with the circuit structure 20.

Illustratively, the material of the auxiliary electrode 40 may include a metal. For example, gold, aluminum, etc.

In some examples, the auxiliary electrode 40 may be prepared using an evaporation process and a lift-off process. In other examples, the auxiliary electrode 40 may be prepared using a sputtering process and an etching process.

The second dielectric layer 50 is located on a side of the first dielectric layer 30 remote from the substrate 10 and covers the auxiliary electrode 40.

It is understood that the second dielectric layer 50 covers the auxiliary electrode 40, and not only the second dielectric layer 50 completely covers the auxiliary electrode 40, but also a part of the auxiliary electrode 40 may be covered by the second dielectric layer 50.

In some examples, the material of the second dielectric layer 50 may include an insulating dielectric such as silicon nitride, silicon oxide, aluminum oxide, or the like.

In some examples, the thickness d2 of the second dielectric layer 50 may be 10nm to 5 μm. For example, the thickness d2 of the second dielectric layer 50 may be 10nm, 100nm, 500nm, 1 μm, 2 μm, 4 μm, 5 μm, or the like.

Therefore, on one hand, the situation that the auxiliary electrode cannot be normally protected due to the fact that the thickness of the second dielectric layer 50 is smaller, the insulation capability is poor can be avoided, and on the other hand, the problem that the cost is high due to the fact that the thickness of the second dielectric layer 50 is larger can be avoided.

The radio frequency device 300 provided by the embodiment of the application comprises the first dielectric layer 30 and the second dielectric layer 50 positioned on one side of the first dielectric layer 30 far away from the substrate 10, wherein the difference between the distances from any two points in the second surface S2 of the first dielectric layer 30 to the upper surface S0 of the substrate 10 is less than or equal to 20nm in the direction perpendicular to the substrate 10, so that the whole second surface S2 is relatively flat. In this way, even if the merging gap 31 is generated in the portion of the first dielectric layer 30 located on the step surface S11 in the process of forming the first dielectric layer 30 (see fig. 4 to 6), the merging gap cannot be formed in the portion of the second dielectric layer 50 located on the side of the step surface S11 away from the substrate 10, and the merging gap 31 in the first dielectric layer 30 cannot be communicated with the outside through the second dielectric layer 50, so that moisture in the external environment cannot easily enter the merging gap 31 of the first dielectric layer 30 and enter the circuit structure 20 through the merging gap 31, thereby avoiding the problem that the first dielectric layer is cracked due to intrusion of moisture, further avoiding the problem that the moisture contacts with electrodes in the circuit structure, causing corrosion of the electrodes to cause mutual short-circuit between the electrodes of the same layer, improving the moisture-proof and waterproof characteristics of the radio frequency device 300, and improving the reliability of the radio frequency device 300.

Fig. 4-6 provide 3 different configurations of the rf device 300, the primary difference being the different topography of the second surface S2 of the first dielectric layer 30.

As shown in fig. 4, in some embodiments, the second surface S2 may be parallel to the upper surface S0 of the substrate 10.

At this time, the second surface S2 is flatter, and the portion of the second surface S2 located on the step surface S11 is flatter. In this way, the second dielectric layer 50 located at the side of the first dielectric layer 30 away from the substrate 10 will not generate a merging gap at the position corresponding to the step surface S11, so that water vapor in the external environment is less likely to pass through the first dielectric layer 30 and the second dielectric layer 50 and enter the circuit structure 20, thereby further improving the moisture-proof and waterproof properties of the radio frequency device 300 and improving the reliability of the radio frequency device 300.

As shown in fig. 5, in other embodiments, a portion of the second surface S2 covered by the first sub-electrode 41 is a first portion S21, a portion of the second surface S2 located around the first sub-electrode 41 is a second portion S22, and the first portion S21 is further away from the upper surface S0 of the substrate 10 than the second portion S22.

In some examples, as shown in fig. 5, a smooth transition may be made between the first portion S21 and the second portion S22.

Through such setting, the second dielectric layer 50 is difficult to appear merging the gap in the juncture of first portion S21 and second portion S22 to be favorable to avoiding merging the gap to appear in the second dielectric layer 50, steam appears through the circumstances that merging the gap corrodes the auxiliary electrode, has further improved the dampproofing and waterproofing characteristic of radio frequency device 300, has improved the stability of radio frequency device 300.

As shown in fig. 6, in still other embodiments, a portion of the second surface S2 located above the step surface S11 is farther from the upper surface S0 of the substrate 10 than a peripheral portion thereof.

It will be appreciated that only three possible topographies of the second surface S2 are shown in the above embodiments, and the topography of the second surface S2 in the present embodiment is not limited thereto.

In some embodiments, as shown in fig. 7, the radio frequency device 300 may further include a third dielectric layer 60. The third dielectric layer 60 is located between the first dielectric layer 30 and the first sub-electrode 41. The second sub-electrode 42 also extends through the third dielectric layer 60.

Illustratively, the material of the third dielectric layer 60 may include an insulating dielectric such as silicon nitride, silicon oxide, aluminum oxide, and the like.

The thickness d3 of the third dielectric layer 60 may be, for example, 10nm to 5 μm. For example, the thickness d3 of the third dielectric layer 60 may be 10nm, 100nm, 500nm, 1 μm, 2 μm, 4 μm, 5 μm, or the like.

In the embodiment of the present application, since the second surface S2 is relatively flat, and the portion of the second surface located on the step surface S11 is relatively flat, no merging gap will occur in the portion of the third dielectric layer 60 located on the side of the step surface S11 away from the substrate 10. In this way, even if the merging slit 31 (see fig. 7) appears in the portion of the first dielectric layer 30 located on the step surface S11, the merging slit appears in the second dielectric layer 50, and the third dielectric layer 60 may space the merging slit 31 in the first dielectric layer 30 from the merging slit in the second dielectric layer 50, thereby further avoiding the communication between the merging slit 31 in the first dielectric layer 30 and the external environment, further blocking the intrusion of water vapor, improving the moisture-proof and waterproof characteristics of the radio frequency device 300, and improving the reliability of the radio frequency device 300.

As shown in fig. 7 and 8, the third dielectric layer 60 includes a third surface S3 remote from the substrate 10. The morphology of the third surface S3 may be slightly different based on the different preparation of the auxiliary electrode 40.

For example, when the auxiliary electrode 40 is prepared using a lift-off process, the third dielectric layer 60 is not easily damaged, and at this time, as shown in fig. 7, the third surface S3 may be parallel to the upper surface S0 of the substrate 10.

At this time, the third surface S3 is flat, and the portion of the third surface S3 located on the step surface S11 is also flat. In this way, the second dielectric layer 50 located at one side of the third dielectric layer 60 away from the substrate 10, the second dielectric layer 50 will not generate a merging gap at the position corresponding to the step surface S11, so that water vapor in the external environment is less likely to pass through the second dielectric layer 50, the third dielectric layer 60 and the first dielectric layer 30 to enter the circuit structure 20, thereby further improving the moisture-proof and waterproof properties of the radio frequency device 300 and improving the reliability of the radio frequency device 300.

For another example, when the auxiliary electrode 40 is prepared by using an etching process, the third dielectric layer is easily etched, and at this time, as shown in fig. 8, the third dielectric layer 60 includes a third surface S3 far from the substrate 10, a portion of the third surface S3 covered by the first sub-electrode 41 is a third portion S31, a portion of the third surface S3 located around the first sub-electrode 41 is a fourth portion S32, and the third portion S31 is further away from the upper surface S0 of the substrate 10 than the fourth portion S32.

The circuit structure 20 is further described below with reference to fig. 4-10.

In some embodiments, as shown in fig. 4-8, the circuit structure 20 may include a heterojunction 21, a fourth dielectric layer 22, a source electrode 23, a drain electrode 24, a fifth dielectric layer 25, and a gate electrode 26.

The heterojunction 21 is located on one side of the substrate 10. The heterojunction 21 includes a channel layer 211 and a barrier layer 212 sequentially stacked in a direction away from the substrate 10.

Illustratively, the material of the channel layer 211 may include GaN. The thickness of the channel layer 211 may be 100nm to 5 μm. For example, the thickness of the channel layer 211 may be 100nm, 200nm, 500nm, 1 μm, 5 μm, or the like.

Illustratively, the material of the barrier layer 212 may include aluminum gallium nitride (AlGaN), aluminum nitride (AlN), indium gallium nitride (InGaN), and the like. The thickness of the barrier layer 212 may be 2nm to 5 μm. For example, the barrier layer 212 has a thickness of 2nm, 100nm, 500nm, 1 μm, 5 μm, or the like.

Among them, the channel layer 211 and the barrier layer 212 form a heterojunction, and two-dimensional electron gas is generated by polarization.

A fourth dielectric layer 22 is located on the side of the heterojunction 21 remote from the substrate 10.

Illustratively, the material of the fourth dielectric layer 22 may include an insulating medium such as silicon nitride, silicon oxide, aluminum oxide, and the like. The thickness of the fourth dielectric layer 22 may be 1nm to 5 μm. For example, the thickness of the fourth dielectric layer 22 may be 1nm, 10nm, 100nm, 500nm, 1 μm, 3 μm, 5 μm, or the like.

The source 23 and the drain 24 are located on a side of the fourth dielectric layer 22 remote from the substrate 10, and the source 23 and the drain 24 penetrate through the fourth dielectric layer 22 to contact the barrier layer 212.

Among them, ohmic contacts may be formed between the source and drain electrodes 23 and 24 and the barrier layer 212.

Illustratively, the material of the source 23 and drain 24 may include a metal, such as titanium, aluminum, gold, and the like.

In some examples, the materials of the source electrode 23 and the drain electrode 24 may be the same, so that the source electrode 23 and the drain electrode 24 may be simultaneously manufactured, thereby simplifying the manufacturing process of the rf device 300, improving the manufacturing efficiency of the rf device 300, and reducing the manufacturing cost of the rf device 300.

A fifth dielectric layer 25 is located on the side of the fourth dielectric layer 22 remote from the substrate 10, the fifth dielectric layer 25 covering the source 23 and drain 24.

It is understood that the fifth dielectric layer 25 covers the source electrode 23 and the drain electrode 24, and includes not only a case where the fifth dielectric layer 25 completely covers the source electrode 23 and the drain electrode 24 but also a case where the fifth dielectric layer 25 covers a part of the source electrode 23 and a part of the drain electrode 24.

Illustratively, the material of the fifth dielectric layer 25 may include an insulating medium such as silicon nitride, silicon oxide, aluminum oxide, etc.

The thickness of the fifth dielectric layer 25 may also be 1nm to 5 μm, for example. For example, the thickness of the fifth dielectric layer 25 may be 1nm, 10nm, 100nm, 500nm, 1 μm, 3 μm, 5 μm, or the like.

The gate 26 is located on a side of the fifth dielectric layer 25 away from the substrate 10 and between the source 23 and the drain 24, and the gate 26 penetrates through the fourth dielectric layer 22 and the fifth dielectric layer 25 to contact the barrier layer 212.

Wherein a schottky contact may be formed between the gate 26 and the barrier layer 212.

Illustratively, the material of the gate 26 may also include a metal, such as nickel, gold, and the like.

In the operating state of the circuit structure 20 provided in the above embodiment, the source electrode 23 and the drain electrode 24 can make two-dimensional electron gas flow in the channel layer 211 between the source electrode 23 and the drain electrode 24 under the action of the electric field, and conduction between the source electrode 23 and the drain electrode 24 occurs at the two-dimensional electron gas in the channel layer 211. A gate electrode 26 is disposed between the source electrode 23 and the drain electrode 24 for allowing or blocking the flow of two-dimensional electron gas, thereby controlling the on or off of the radio frequency device.

In an embodiment of the present application, referring to fig. 8, the first surface S1 of the circuit structure 20 may include a surface of the fifth dielectric layer 25 not covered by the gate 26, and a top surface 261 and a sidewall 262 of the gate 26. The portion of the first surface S1 located above the edges of the source electrode 23 and the drain electrode 24 forms a step surface S11, and the top surface 261 and the side wall 262 of the gate electrode also form a step surface S11.

In an embodiment of the present application, the rf device 300 may include a plurality of auxiliary electrodes 40.

In some examples, the source electrode 23, the drain electrode 24, and the gate electrode 26 may be respectively connected with one auxiliary electrode 40. Based on the above-described circuit structure 20, the auxiliary electrode 40 correspondingly connected to the source electrode 23 may be in electrical contact with the source electrode 23 through the first dielectric layer 30 and the fifth dielectric layer 25, the auxiliary electrode 40 correspondingly connected to the drain electrode 24 may be in electrical contact with the drain electrode 24 through the first dielectric layer 30 and the fifth dielectric layer 25, and the auxiliary electrode 40 correspondingly connected to the gate electrode 26 may be in electrical contact with the gate electrode 26 through the first dielectric layer 30.

In other examples, the drain electrode 24 and the gate electrode 26 may be respectively connected to one auxiliary electrode 40, and the source electrode 23 may not be electrically connected to the auxiliary electrode.

In some embodiments, as shown in fig. 9, the circuit structure 20 may further include a sixth dielectric layer 27 and a field plate (FIELD PLATE, FP) electrode 28, the sixth dielectric layer 27 is located on a side of the fifth dielectric layer 25 away from the substrate 10, and the sixth dielectric layer 27 covers the gate 26. The field plate electrode 28 is located on the side of the sixth dielectric layer 27 remote from the substrate 10, and the orthographic projection of the field plate electrode 28 onto the substrate 10 overlaps with the orthographic projection of the gate electrode 26 onto the substrate 10.

It is understood that the sixth dielectric layer 27 covers the gate 26, and the sixth dielectric layer 27 may completely cover the gate 26, or the sixth dielectric layer 27 may cover a portion of the gate 26.

Illustratively, the material of the sixth dielectric layer 27 may include an insulating medium such as silicon nitride, silicon oxide, aluminum oxide, etc.

The thickness of the sixth dielectric layer 27 may be, for example, 1nm to 5 μm. For example, the thickness of the sixth dielectric layer 27 may be 1nm, 10nm, 100nm, 500nm, 1 μm, 3 μm, 5 μm, or the like.

By way of example, the material of the field plate electrode 28 may be a metal, such as gold, aluminum, or the like.

In some examples, field plate electrode 28 may not be in contact with gate 26, source 23, or drain 24, and thus may not be loaded with any signal. In other examples, field plate electrode 28 may be electrically connected to source 23. In still other examples, field plate electrode 28 may be electrically connected to gate 26.

In the embodiment of the application, the field plate electrode 28 is arranged on the fifth dielectric layer 25, and the orthographic projection of the field plate electrode 28 on the substrate 10 overlaps with the orthographic projection of the grid electrode 26 on the substrate 10, so that the electric field distribution in the radio frequency device 300 can be adjusted, the electric field distribution at the position where the edge of the grid electrode 26 is located is more uniform, the electric field peak is avoided, and the breakdown resistance of the radio frequency device is improved.

On the basis of this, the first surface S1 of the circuit structure 20 may comprise the portion of the sixth dielectric layer 27 not covered by the field plate electrode 28, as well as the top surface 281 and the side walls 282 of the field plate electrode 28. Wherein the portion of the first surface S1 above the edges of the source 23, drain 24 and gate 26 forms a step surface S11, the top surface 281 and the side wall 282 of the field plate electrode 28 also forms a step surface S11.

In some examples, the top surface 281 of the field plate electrode 28 may be undulating, i.e., there are two points on the top surface 281 of the field plate electrode 28 that differ in distance from the upper surface S0 of the substrate 10 in a direction perpendicular to the substrate 10.

In other examples, the top surface 281 of the field plate electrode 28 may be parallel to the substrate 10.

In some embodiments, as shown in fig. 10, the heterojunction 21 may further comprise an insertion layer 213 between the channel layer 211 and the barrier layer 212.

Illustratively, the material of the insertion layer 213 may include AlN.

The insertion layer 213 is located between the channel layer 211 and the barrier layer 212, and is used for increasing the concentration of the two-dimensional electron gas, reducing the infiltration amount of the two-dimensional electron gas into the barrier layer, and reducing the disordered scattering of the alloy, thereby increasing the electron mobility and improving the output characteristics of the radio frequency device 300.

With continued reference to fig. 10, in other embodiments, the circuit structure 20 may further include a nucleation layer 291 and a buffer layer 292. The nucleation layer 291 is located between the substrate 10 and the channel layer 211, and the buffer layer 292 is located between the nucleation layer 291 and the channel layer 211.

Illustratively, the material of the nucleation layer 291 may include one or more of GaN, alGaN, alN.

By providing nucleation layer 291, epitaxial quality can be improved, facilitating the growth of upper epitaxial materials (e.g., the material of buffer layer 292).

For example, the material of the buffer layer 292 may include AlGaN and/or AlN. For example, the material of the buffer layer 292 includes AlGaN, wherein the composition of Al in AlGaN may decrease with increasing thickness. For another example, the material of the buffer layer 292 may include AlGaN and AlN, in which case the buffer layer 292 may be superlattice in structure.

By providing the buffer layer 292, stress of a plurality of film layers (e.g., the channel layer 211 and the barrier layer 212) on the substrate 10 can be relieved, on the one hand, and the breakdown resistance of the radio frequency device 300 can be improved, on the other hand.

With continued reference to fig. 10, in still other embodiments, the circuit structure 20 may further include a cap layer 293, the cap layer 293 being located between the barrier layer 212 and the fourth dielectric layer 22. The cap layer 293 is used to protect the barrier layer 212.

Illustratively, the material of cap layer 293 may include aluminum nitride, aluminum gallium nitride, or gallium nitride.

The cap layer 293 may have a thickness of 1nm to 5nm, for example. For example, the cap layer 293 may have a thickness of 1nm, 2nm, 3nm, 4nm, 5nm, or the like.

It will be appreciated that the presence of cap layer 293 does not affect the ohmic contact between source 23 and drain 24 and barrier layer 212, nor does the presence of cap layer 293 affect the schottky contact between gate 26 and barrier layer 212.

In some embodiments, the nucleation layer 291, the buffer layer 292, the channel layer 211, the barrier layer 212, and the cap layer 293 may be epitaxially grown on the substrate 10 using a metal-organic chemical vapor deposition (metal-organic chemical vapor deposition, MOCVD) or a molecular beam epitaxy (molecular beam epitaxy, MBE) process.

Fig. 11 is a top view of an rf device 300 according to an embodiment of the application, and fig. 12 is a simplified cross-sectional view of the rf device 300 according to an embodiment of the application.

As shown in fig. 11 and 12, in some embodiments, the radio frequency device 300 includes an active region AA and an inactive region BB surrounding the active region AA. Wherein, 2DEG exists in the active area AA, and 2DEG does not exist in the inactive area BB.

In some examples, at least a portion of source 23 and drain 24 are located within active area AA, a portion of gate 26 is located within active area AA, and another portion of gate 26 is located within inactive area BB.

The radio frequency device 300 may further include a first liner 71, a second liner 72, and a third liner 73. The first liner 71 and the second liner 72 are located on the side of the first dielectric layer 30 remote from the substrate 10. The first and second pads 71 and 72 are located in the inactive region BB, and the first and second pads 71 and 72 are electrically connected to the drain 24 and the gate 26, respectively, through the auxiliary electrode 40. The third pad 73 is located on the side of the substrate 10 remote from the circuit structure 20. The third pad 73 is electrically connected to the source electrode 23.

The "first pad 71 and the second pad 72 are electrically connected to the drain electrode 24 and the gate electrode 26 through the auxiliary electrode 40", respectively, may be that the first pad 71 is electrically connected to the drain electrode 24 through one auxiliary electrode 40, and the second pad 72 is electrically connected to the gate electrode 26 through the other auxiliary electrode 40.

The "first pad 71 and the second pad 72 are electrically connected to the drain electrode 24 and the gate electrode 26 through the auxiliary electrode 40", respectively ", or the first pad 71 may be electrically connected to the gate electrode 26 through one auxiliary electrode 40, and the second pad 72 may be electrically connected to the drain electrode 24 through the other auxiliary electrode 40.

Illustratively, the materials of the first, second, and third pads 71, 72, 73 may each comprise a metal, e.g., gold, aluminum, etc.

In some examples, the materials of the first pad 71, the second pad 72, and the auxiliary electrode 40 may be the same. In this way, the first and second spacers 71 and 72 can be prepared simultaneously with the auxiliary electrode 40, thereby simplifying the preparation process of the radio frequency device 300 and reducing the preparation cost of the radio frequency device 300.

In some examples, as shown in fig. 11, the auxiliary electrode 40 correspondingly connected to the drain electrode 24 may be located in the inactive region BB. In other examples, as shown in fig. 12, a portion of the auxiliary electrode 40 corresponding to the drain electrode 24 is located in the active region AA, and another portion of the auxiliary electrode 40 corresponding to the drain electrode 24 is located in the inactive region BB.

In some examples, as shown in fig. 11, the auxiliary electrode 40 correspondingly connected to the gate electrode 26 may be located in the inactive region BB.

In some examples, as shown in fig. 12, the radio frequency device 300 may further include an interconnect metal 80 on a side of the substrate 10 remote from the circuit structure 20, where the interconnect metal 80 may be electrically connected to the source electrode 23 through a backside via (Bvia) 81.

Illustratively, the back aperture 81 may include portions located in the heterojunction 21, the fourth dielectric layer 22, the buffer layer 292, and the nucleation layer 291.

In some examples, the back holes 81 may be located in the active area AA. In other examples, back hole 81 may be inactive region BB.

In the embodiment of the present application, the position of the third pad 73 is not limited, and the third pad 73 may be located in the active area AA or may be located in the inactive area BB.

The embodiment of the application also provides a preparation method of the radio frequency device 300, as shown in fig. 13, which comprises the following steps:

S100, as shown in fig. 14, a circuit structure 20 is formed on one side of the substrate 10, the circuit structure 20 includes a first surface S1 remote from the substrate 10, the first surface S1 includes a step surface S11, and the step surface S11 includes a protrusion remote from the substrate 10.

The circuit structure 20 may have any of the structures provided in the above embodiments. In fig. 14, only the circuit structure 20 includes the heterojunction 21 (the heterojunction 21 includes the channel layer 211, the barrier layer 212, and the insertion layer 213), the fourth dielectric layer 22, the source electrode 23, the drain electrode 24, the fifth dielectric layer 25, the gate electrode 26, the sixth dielectric layer 27, the field plate electrode 28, the nucleation layer 291, the buffer layer 292, and the cap layer 293 are illustrated as examples.

Illustratively, the heterojunction 21, nucleation layer 291, buffer layer 292, and cap layer 293 may be epitaxially grown on the substrate 10 using a metal-organic chemical vapor deposition or molecular beam epitaxy process.

Illustratively, the fourth dielectric layer 22, the fifth dielectric layer 25, and the sixth dielectric layer 27 may be formed by a process such as plasma chemical vapor deposition, atomic layer deposition, or low pressure chemical vapor deposition.

For example, the source 23, drain 24, gate 26, and field plate electrode 28 may be formed using a deposition process, such as evaporation or sputtering.

The first surface S1 is illustrated in a "thick and black solid line" in fig. 14, and the first surface S1 may include a surface of the sixth dielectric layer 27 not covered by the field plate electrode 28, and the top surface 281 and the side wall 282 of the field plate electrode 28.

S200, as shown in fig. 15, a first dielectric layer 30 is formed on a side of the circuit structure 20 away from the substrate 10. The first dielectric layer 30 includes a second surface S2 remote from the substrate 10, the height of the second surface S2 varying with the height of the first surface S1.

For example, the first dielectric layer 30 may be formed on the side of the circuit structure 20 remote from the substrate 10 using a plasma chemical vapor deposition, atomic layer deposition, low pressure chemical vapor deposition, or the like.

S300, as shown in fig. 16A and 16B, the second surface S2 of the first dielectric layer 30 is planarized.

After the second surface S2 of the first dielectric layer 30 is planarized, a difference between distances from any two points on the second surface S2 to the upper surface S0 of the substrate 10 in a direction perpendicular to the substrate 10 (for example, the second direction Y) is less than or equal to 20nm.

For example, referring to fig. 16A, after the planarization process is performed on the second surface S2 of the first dielectric layer 30, the second surface S2 has any two points, such as a point N1 and a point N2, where a distance from the point N1 to the upper surface S0 of the substrate 10 is h1, a distance from the point N2 to the upper surface S0 of the substrate 10 is h2, and h1 is equal to h2.

Or, for example, referring to fig. 16B, after the second surface S2 of the first dielectric layer 30 is planarized, the second surface S2 has any two points, such as a point N3 and a point N4. The distance from the point N3 to the upper surface S0 of the substrate 10 is h3, the distance from the point N4 to the upper surface S0 of the substrate 10 is h4, h3 is smaller than h4, and the difference between h4 and h3 is smaller than 20nm.

S400, as shown in fig. 17A and 17B, an auxiliary electrode 40 is formed, where the auxiliary electrode 40 includes a first sub-electrode 41 and a second sub-electrode 42 that are connected, the first sub-electrode 41 is located on a side of the first dielectric layer 30 away from the substrate 10, and the second sub-electrode 42 penetrates through the first dielectric layer 30 and is connected to the circuit structure 20.

S500, referring to fig. 4 and 6, a second dielectric layer 50 is formed on a side of the first dielectric layer 30 away from the substrate 10, and the second dielectric layer 50 covers the auxiliary electrode 40.

For example, the second dielectric layer 50 may be formed on the side of the first dielectric layer 30 remote from the substrate 10 using a plasma chemical vapor deposition, atomic layer deposition, or low pressure chemical vapor deposition process.

In the method for manufacturing a radio frequency device provided by the embodiment of the application, the first dielectric layer 30 is formed on the rugged first surface S1, the second surface S2 of the first dielectric layer 30 is rugged, and the second surface S2 of the first dielectric layer 30 is subjected to planarization treatment, so that the second surface S2 of the first dielectric layer 30 is relatively flat. Thus, even if the first dielectric layer 30 generates a merging gap at the step surface S11 corresponding to the first surface S1 in the forming process, after the second dielectric layer 50 is formed on the flat second surface S2, the merging gap will not appear in the part of the second dielectric layer 50, which is located at the side of the step surface S11 away from the substrate 10, and the merging gap 31 in the first dielectric layer 30 cannot communicate with the outside through the second dielectric layer 50, so that water vapor in the external environment cannot easily enter the merging gap of the first dielectric layer 30 and enter the circuit structure 20 through the merging gap, thereby avoiding the problem that the first dielectric layer is cracked due to invasion of water vapor, further avoiding the problem that the water vapor contacts with the electrodes in the circuit structure, causing corrosion of the electrodes at the same layer and causing mutual short circuit between the electrodes, improving the moisture-proof and waterproof characteristics of the radio frequency device 300, and improving the reliability of the radio frequency device 300.

In some embodiments, as shown in fig. 15, the thickness d4 of the first dielectric layer 30 may be 400nm to 5 μm before the planarization process is performed on the second surface S2 of the first dielectric layer 30 in step S300. For example, the thickness of the first dielectric layer 30 may be 400nm, 800nm, 1 μm, 2 μm, 3 μm, 5 μm, or the like.

By this arrangement, on the one hand, the thickness of the first dielectric layer 30 can be not too small, so that the removal amount of the first dielectric layer 30 to be consumed in the planarization treatment can be reserved, and after the planarization treatment is performed on the second surface S2 of the first dielectric layer 30, the first dielectric layer 30 can still better protect the circuit structure 20. On the other hand, the thickness of the first dielectric layer 30 can be kept from becoming too thick, thereby avoiding an increase in cost.

As shown in fig. 18A, in some examples, performing the planarization process on the second surface S2 of the first dielectric layer 30 in step S300 may include:

s310, removing a portion of the first dielectric layer 30 by using a Chemical Mechanical Polishing (CMP) process or a dry etching process, so as to planarize the second surface S2 of the first dielectric layer 30.

Wherein, a dry etching process is adopted, and the etching precision is higher. The chemical mechanical polishing process is adopted, so that the process is easier to realize, the second surface S2 of the first dielectric layer 30 is flatter, and after the second surface S2 of the first dielectric layer 30 is flattened, when the second dielectric layer 50 is formed on one side of the first dielectric layer 30 far away from the substrate 10, a merging gap is not formed in the part of the second dielectric layer 50, which is positioned on one side of the step surface S11 far away from the substrate 10, so that the problem that the first dielectric layer is cracked due to the invasion of water vapor is further avoided, the problem that the water vapor contacts with electrodes in a circuit structure and causes the corrosion of the electrodes to cause the mutual short circuit among the electrodes on the same layer is solved, the dampproof and waterproof characteristics of the radio frequency device 300 are improved, and the reliability of the radio frequency device 300 is improved.

As shown in fig. 18B, in other examples, the step S300 of planarizing the second surface S2 of the first dielectric layer 30 may include:

As shown in fig. 19, a sacrificial layer 11 is formed on the side of the first dielectric layer 30 away from the substrate 10 at S320. The sacrificial layer 11 comprises a fourth surface S4 remote from the substrate 10, the height of the fourth surface S4 varying with the variation of the second surface S2.

Illustratively, the material of the sacrificial layer 11 may include an organic material, for example, polyimide (PI), photosensitive coated glass, photoresist, or the like.

When the material of the sacrificial layer 11 includes photoresist, the material of the sacrificial layer 11 may be silicon compound photoresist (hydrogen silsesquioxane, HSQ).

The thickness of the sacrificial layer 11 may be, for example, 100nm to 5 μm. For example, the thickness of the sacrificial layer 11 may be 100nm, 500nm, 1 μm, 2 μm, 5 μm, or the like.

And S330, removing at least part of the sacrificial layer 11 by adopting a dry etching process so as to flatten the second surface S2 of the first dielectric layer 30.

In the embodiment of the application, the sacrificial layer 11 is formed to fill the lower part of the second surface S2 of the first dielectric layer 30, and the first dielectric layer 30 is planarized by a dry etching process based on the characteristics of high etching speed and low etching speed.

In some examples, "removing at least part of the sacrificial layer 11 to planarize the second surface S2 of the first dielectric layer 30" may be removing part of the sacrificial layer 11, and filling the remaining sacrificial layer 11 in the lower portion of the second surface S2 to planarize the second surface S2.

In other examples, "removing at least part of the sacrificial layer 11 to planarize the second surface S2 of the first dielectric layer 30" may be removing part of the sacrificial layer 11, and a portion of the first dielectric layer 30 that is higher (a portion farther from the upper surface S0 of the substrate 10), and filling the remaining sacrificial layer 11 at a lower portion of the second surface S2 to planarize the second surface S2.

In still other examples, "removing at least a portion of the sacrificial layer 11 to planarize the second surface S2 of the first dielectric layer 30" may be removing all of the sacrificial layer 11 and a portion of the first dielectric layer 30 to planarize the second surface S2.

It should be understood that fig. 18A and 18B only show two manners of planarizing the second surface S2 of the first dielectric layer 30, and the manner of planarizing the second surface S2 of the first dielectric layer 30 in the embodiment of the present application is not limited thereto.

In some embodiments, as shown in fig. 20, step S400 of forming the auxiliary electrode 40 includes:

s410, as shown in fig. 21, the first dielectric layer 30 is etched to form an opening 301, where the opening 301 exposes the source 23, the drain 24, or the gate 26 in the circuit structure.

In some examples, etching the first dielectric layer 30 may form a plurality of openings 301. At this time, for example, the source electrode 23, the drain electrode 24, and the gate electrode 26 may each correspond to one opening 301. For another example, the drain 24 and the gate 26 each correspond to one of the openings 301.

In the embodiment of the present application, the shape and size of the opening 301 are not limited, as long as a part of the surface of the source electrode 23, the drain electrode 24 or the gate electrode 26 can be exposed.

As shown in fig. 22, the conductive layer 12 is formed on the side of the first dielectric layer 30 away from the substrate 10.

Illustratively, a sputtering process may be used to form conductive layer 12 on the side of first dielectric layer 30 remote from substrate 10.

S430, referring to fig. 5, the conductive layer 12 is etched to form the auxiliary electrode 40. The auxiliary electrode 40 includes a first sub-electrode 41 located on the second surface S2 and a second sub-electrode 42 located in the opening 301. The second sub-electrode 42 is connected to the source 23, the drain 24 or the gate 26.

As shown in fig. 5, in the process of etching the conductive layer 12, in order to completely remove the unnecessary portion of the conductive layer 12, over etching is required such that the first portion S21 of the second surface S2 is farther from the upper surface S0 of the substrate 10 than the second portion S22, wherein the first portion S21 is a portion of the second surface S2 covered by the first sub-electrode 41, and the second portion S22 is a portion of the second surface S2 located around the first sub-electrode 41.

In other embodiments, as shown in fig. 23, step S400 of forming the auxiliary electrode 40 includes:

s440, as shown in fig. 21, the first dielectric layer 30 is etched to form an opening 301, where the opening 301 exposes the source 23, the drain 24, or the gate 26 in the circuit structure.

In some examples, an evaporation process may be used to form conductive layer 12 on a side of first dielectric layer 30 remote from substrate 10.

S460, referring to fig. 17A and 17B, a stripping process is used to remove a portion of the conductive layer 12, so as to form the auxiliary electrode 40. The auxiliary electrode 40 includes a first sub-electrode 41 located on the second surface S2 and a second sub-electrode 42 located in the opening 301. The second sub-electrode 42 is connected to the source 23, the drain 24 or the gate 26.

For example, after the opening 301 is formed by etching the first dielectric layer 30 in step S440, a patterned photoresist layer may be formed on the side of the first dielectric layer 30 away from the substrate 10 before the conductive layer 12 is formed on the side of the first dielectric layer 30 away from the substrate 10 in step S440, so that after the conductive layer 12 is formed, the photoresist may be removed by using a stripping solution, and the conductive layer 12 over the photoresist, thereby removing a portion of the conductive layer 12.

In this way, the first dielectric layer 30 is not easily damaged during the process of preparing the auxiliary electrode 40, and the second surface S2 of the first dielectric layer 30 can maintain the planarized morphology.

When preparing the auxiliary electrode 40, the second surface S2 of the first dielectric layer 30 can be planarized to make the photoresist thickness uniform, and the photoresist curing effect after development is better, so that the redundant part in the conductive layer is better removed in the etching or stripping process, and the metal residue is avoided.

In some embodiments, as shown in fig. 24, after the planarization process is performed on the second surface S2 of the first dielectric layer 30 in step 300, before the auxiliary electrode 40 is formed in step S400, the preparation method further includes:

S600, as shown in fig. 25A and 25B, a third dielectric layer 60 is formed on the side of the first dielectric layer 30 away from the substrate 10. Wherein the second portion 42 also extends through the third dielectric layer 60.

For example, the third dielectric layer 60 may be formed on the side of the first dielectric layer 30 away from the substrate 10 using a plasma chemical vapor deposition, atomic layer deposition, or low pressure chemical vapor deposition process.

Since the second surface S2 is relatively flat, no merging gap occurs in the portion of the third dielectric layer 60 on the side of the step surface S11 away from the substrate 10. In this way, even if the merging gap appears in the portion of the first dielectric layer 30 located on the step surface S11, the merging gap appears in the second dielectric layer 50, and the third dielectric layer 60 may space the merging gap in the first dielectric layer 30 from the merging gap in the second dielectric layer 50, thereby further avoiding the communication between the merging gap in the first dielectric layer 30 and the external environment, further blocking the intrusion of water vapor, improving the moisture-proof and waterproof properties of the radio frequency device 300, and improving the reliability of the radio frequency device 300.

Referring to fig. 8, it can be understood that the third dielectric layer 60 is formed on the side of the first dielectric layer 30 away from the substrate 10, and then the auxiliary electrode 40 is formed, and the third dielectric layer 60 can be used to protect the first dielectric layer 30, so as to avoid etching the first dielectric layer during the formation of the auxiliary electrode 40, and thus the first dielectric layer 30 can better protect the circuit structure 20.

In the description of the present specification, a particular feature, structure, material, or characteristic may be combined in any suitable manner in one or more embodiments or examples.

The foregoing is merely illustrative embodiments of the present application, but the scope of the present application is not limited thereto, and any person skilled in the art can easily think about variations or substitutions within the technical scope of the present application, and the application should be covered. Therefore, the protection scope of the application is subject to the protection scope of the claims.

Claims

1. A radio frequency device, comprising:

A substrate;

A circuit structure located on one side of the substrate, the circuit structure comprising a first surface remote from the substrate, the first surface comprising a step surface comprising a protrusion remote from one side of the substrate;

The first dielectric layer is positioned on one side of the first surface away from the substrate; the first dielectric layer comprises a second surface far away from the substrate; in a direction perpendicular to the substrate, a difference between distances from any two points in the second surface to an upper surface of the substrate is less than or equal to 20nm;

The auxiliary electrode comprises a first sub-electrode and a second sub-electrode which are connected, the first sub-electrode is positioned on one side of the first dielectric layer far away from the substrate, and the second sub-electrode penetrates through the first dielectric layer and is connected with the circuit structure;

And the second dielectric layer is positioned on one side of the first dielectric layer away from the substrate and covers the auxiliary electrode.

2. The radio frequency device of claim 1, wherein the second surface is parallel to an upper surface of the substrate.

3. The radio frequency device according to claim 1, wherein the portion of the second surface covered by the first sub-electrode is a first portion, the portion of the second surface located around the first sub-electrode is a second portion, and the first portion is further from the upper surface of the substrate than the second portion.

4. The radio frequency device according to claim 1 or 2, further comprising:

the third dielectric layer is positioned between the first dielectric layer and the first sub-electrode; the second sub-electrode also penetrates through the third dielectric layer.

5. The rf device of claim 4, wherein the third dielectric layer includes a third surface remote from the substrate, the portion of the third surface covered by the first sub-electrode being a third portion, the portion of the third surface surrounding the first sub-electrode being a fourth portion, the third portion being further from the upper surface of the substrate than the fourth portion.

6. The radio frequency device of claim 4, wherein the third dielectric layer includes a third surface remote from the substrate, the third surface being parallel to the upper surface of the substrate.

7. The radio frequency device according to any one of claims 1 to 6, wherein the circuit structure comprises:

A heterojunction positioned on one side of the substrate; the heterojunction comprises a channel layer and a barrier layer which are sequentially laminated along a direction away from the substrate;

the fourth dielectric layer is positioned on one side of the heterojunction far away from the substrate;

the source electrode and the drain electrode are positioned on one side, far away from the substrate, of the fourth dielectric layer, and penetrate through the fourth dielectric layer to be in contact with the barrier layer;

The fifth dielectric layer is positioned on one side, far away from the substrate, of the fourth dielectric layer, and the fifth dielectric layer covers the source electrode and the drain electrode;

the grid electrode is positioned on one side of the fifth dielectric layer away from the substrate and is positioned between the source electrode and the drain electrode; and the grid penetrates through the fourth dielectric layer and the fifth dielectric layer and is in contact with the barrier layer.

8. The radio frequency device of claim 7, wherein the circuit structure further comprises:

the sixth dielectric layer is positioned on one side, far away from the substrate, of the fifth dielectric layer, and the sixth dielectric layer covers the grid electrode;

And the field plate electrode is positioned on one side of the sixth dielectric layer far away from the substrate, and the orthographic projection of the field plate electrode on the substrate is overlapped with the orthographic projection part of the grid electrode on the substrate.

9. The radio frequency device according to claim 7 or 8, wherein the radio frequency device comprises an active region and a passive region surrounding the active region;

The radio frequency device further includes a first liner, a second liner, and a third liner; the first liner and the second liner are positioned on one side of the first dielectric layer away from the substrate; the first pad and the second pad are positioned in the passive region, and the first pad and the second pad are electrically connected with the drain electrode and the gate electrode through the auxiliary electrode respectively;

The third pad is positioned on one side of the substrate away from the circuit structure; the third pad is electrically connected with the source electrode.

10. The radio frequency device according to any one of claims 1 to 9, wherein a portion of the second dielectric layer on a side of the step surface remote from the substrate has no merging slit.

11. A method of manufacturing a radio frequency device, comprising:

Forming a circuit structure on one side of a substrate, wherein the circuit structure comprises a first surface far away from the substrate, the first surface comprises a step surface, and the step surface comprises a protrusion far away from one side of the substrate;

Forming a first dielectric layer on one side of the circuit structure away from the substrate; the first dielectric layer comprises a second surface far away from the substrate, and the height of the second surface changes along with the change of the height of the first surface;

Flattening the second surface of the first dielectric layer;

forming an auxiliary electrode, wherein the auxiliary electrode comprises a first sub-electrode and a second sub-electrode which are connected, the first sub-electrode is positioned on one side of the first dielectric layer far away from the substrate, and the second sub-electrode penetrates through the first dielectric layer to be connected with the circuit structure;

forming a second dielectric layer on one side of the first dielectric layer far away from the substrate, wherein the second dielectric layer covers the auxiliary electrode;

After the second surface of the first dielectric layer is subjected to planarization treatment, the difference between the distances from any two points in the second surface to the upper surface of the substrate in the direction perpendicular to the substrate is less than or equal to 20nm.

12. The method of claim 11, wherein planarizing the second surface of the first dielectric layer comprises:

And removing part of the first dielectric layer by adopting a chemical mechanical polishing process or a dry etching process so as to flatten the second surface of the first dielectric layer.

13. The method of claim 11, wherein planarizing the second surface of the first dielectric layer comprises:

Forming a sacrificial layer on one side of the first dielectric layer away from the substrate; the sacrificial layer includes a fourth surface remote from the substrate, the fourth surface having a height that varies with the second surface;

And removing at least part of the sacrificial layer by adopting a dry etching process so as to flatten the second surface of the first dielectric layer.

14. The method of claim 13, wherein the material of the sacrificial layer comprises an organic material.

15. The method of any one of claims 11 to 14, wherein forming the auxiliary electrode comprises:

Etching the first dielectric layer to form an opening, wherein the opening exposes a source electrode, a drain electrode or a grid electrode in the circuit structure;

forming a conductive layer on one side of the first dielectric layer away from the substrate;

Etching the conductive layer to form an auxiliary electrode; the auxiliary electrode comprises a first sub-electrode positioned on the second surface and a second sub-electrode positioned in the opening; the second sub-electrode is electrically connected to the source electrode, the drain electrode, or the gate electrode.

16. The method of any one of claims 11 to 14, wherein forming the auxiliary electrode comprises:

removing part of the conductive layer by adopting a stripping process to form an auxiliary electrode; the auxiliary electrode comprises a first sub-electrode positioned on the second surface and a second sub-electrode positioned in the opening; the second sub-electrode is electrically connected to the source electrode, the drain electrode, or the gate electrode.

17. The method according to any one of claims 11 to 14, wherein after the planarizing the second surface of the first dielectric layer, the method further comprises, before the forming of the auxiliary electrode:

Forming a third dielectric layer on one side of the first dielectric layer far away from the substrate;

Wherein the second portion also extends through the third dielectric layer.

18. The method according to any one of claims 11 to 17, wherein a thickness of the first dielectric layer is 400nm to 5 μm before the planarization treatment is performed on the second surface of the first dielectric layer.

19. An electronic device, comprising:

The electrical circuit board is provided with a plurality of circuit boards,

The radio frequency device of any of claims 1-10, electrically connected to the circuit board.