A power device and a method for manufacturing the same

Abstract

The present invention discloses a power device, comprising at least one vacuum-encapsulated unit structure; wherein the unit structure comprises: a silicon substrate and an emitter, a light modulator and a collector formed on the silicon substrate. On the one hand, since the entire device is prepared using a unified silicon-based process, the problem of inconsistency in the process preparation of the emitter of the traditional cold cathode field emission is solved, the internal precision and consistency of the device are improved, and the reliability of the device is enhanced; on the other hand, based on the silicon-based process, a light modulator formed on the silicon substrate is introduced, the field emission efficiency of the emitter is enhanced, the inconsistency between the emitter tip and the collector caused by the emitter non-uniformity is offset, and the process redundancy of the cold cathode emission electrode is increased, so that the device does not need to rely entirely on the field emission principle to generate electrons, the load of field emission is reduced, and the reliability of the device is further enhanced.

Description

Technical Field

[0001] The invention relates to the field of vacuum microelectronic technology, and in particular to a power device and a preparation method thereof. Background Art

[0002] The withstand voltage of existing power devices is borne by the spatial electric field of semiconductor junctions (e.g., PN junctions), which limits the on-resistance and working efficiency of the devices. Although the existing field-induced cathode emission vacuum microelectronic power devices can improve the withstand voltage of power devices, their electron emission is completely dependent on electric field emission, so their power and reliability cannot be guaranteed, and thus the products are not mature. Summary of the invention

[0003] The embodiments of the present application solve the technical problem of low reliability of existing power devices by providing a power device and a method for manufacturing the same.

[0004] On the one hand, the present application provides the following technical solution through an embodiment of the present application:

[0005] A power device, comprising at least one vacuum-encapsulated unit structure; wherein the unit structure comprises:

[0006] Silicon substrate;

[0007] An emitter is formed on the silicon substrate by using a silicon-based process;

[0008] A light modulator is formed on the silicon substrate by using a silicon-based process, and the light modulator is used to generate photons to stimulate the emitter to emit electrons;

[0009] A collector electrode is formed on the silicon substrate by using a silicon-based process, and the collector electrode is used to excite the electrons emitted by the emitter electrode.

[0010] Optionally, the unit structure further includes:

[0011] A gate is formed on the silicon substrate by using a silicon-based process, and the gate is used to generate an electric field to stimulate the emitter to emit electrons.

[0012] Optionally, the light modulation pole is an LED structure with lateral light emission.

[0013] Optionally, the light modulator is an extreme ultraviolet LED.

[0014] Optionally, the ultraviolet LED includes an N-type semiconductor material, a P-type semiconductor material, and a resonant cavity formed by the N-type semiconductor material and the P-type semiconductor material.

[0015] Optionally, the N-type semiconductor material and the P-type semiconductor material are gallium nitride, indium gallium nitride or aluminum gallium nitride.

[0016] Optionally, the emitter includes a silicon-based micro-tip structure and a metal layer covering the silicon-based micro-tip structure.

[0017] Optionally, the vacuum packaging pressure is 10 -6 Pa~10Pa.

[0018] Optionally, the power device includes at least two of the unit structures, and the two unit structures are mirror-integrated along the optical modulation pole.

[0019] Optionally, a bonding cover plate is also formed on the two unit structures mirror-integrated along the light modulating pole.

[0020] On the other hand, the present application provides a method for preparing a power device through another embodiment of the present application, the method is used to prepare the above-mentioned unit structure; the method comprises:

[0021] preparing a silicon substrate;

[0022] Epitaxially preparing a light modulator on a silicon substrate, wherein the cathode of the light modulator is connected to the silicon substrate, and the anode of the light modulator is led out as a light modulation control electrode;

[0023] Preparing an emitter on the silicon substrate next to the light modulator;

[0024] The prepared collector electrode is combined with the silicon substrate through a silicon wafer bonding process to form a unit structure.

[0025] One or more technical solutions provided in the embodiments of the present application have at least the following technical effects or advantages:

[0026] The vacuum-encapsulated unit structure of a power device includes: a silicon substrate; an emitter formed on the silicon substrate using a silicon-based process; an optical modulator formed on the silicon substrate using a silicon-based process, the optical modulator is used to generate photons to excite the emitter to emit electrons; and a collector formed on the silicon substrate using a silicon-based process, the collector is used to excite the electrons emitted by the emitter. On the one hand, since the entire device is prepared using a unified silicon-based process, the problem of inconsistency in the process preparation of the emitter of the traditional cold cathode field emission is solved, the internal accuracy and consistency of the device are improved, and the reliability of the device is enhanced; on the other hand, based on the silicon-based process, the optical modulator formed on the silicon substrate is introduced, the field emission efficiency of the emitter is enhanced, the inconsistency between the emitter tip and the collector caused by the emitter non-uniformity is offset, and the process redundancy of the cold cathode emission electrode is increased, so that the device does not need to rely entirely on the field emission principle to generate electrons, the load of field emission is reduced, and the reliability of the device is further enhanced. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without creative work.

[0028] Figure 1 is a schematic diagram of a unit structure of a power device according to an embodiment of the present invention;

[0029] Figure 2 is another schematic diagram of a unit structure of a power device according to an embodiment of the present invention;

[0030] Figure 3 yes Figure 1 Schematic diagram of the emitter structure in ;

[0031] Figure 4 It is a schematic structural diagram of a power device according to an embodiment of the present invention;

[0032] Figure 5 The present invention is a flowchart of a method for preparing a power device according to another embodiment of the present invention.

[0033] The following are the descriptions of the reference numerals:

[0034] 100. Silicon substrate, 200. Emitter, 210. Silicon-based micro-tip structure, 220. Metal layer, 300. Light modulator, 400. Collector, 500. Gate, 600. Bonding cover. DETAILED DESCRIPTION

[0035] The embodiments of the present application solve the technical problem of low reliability of existing power devices by providing a power device and a method for manufacturing the same.

[0036] The technical solution of the embodiment of the present application is to solve the above technical problems, and the overall idea is as follows:

[0037] A power device includes at least one vacuum-encapsulated unit structure; wherein the unit structure includes: a silicon substrate 100; an emitter 200 formed on the silicon substrate 100 using a silicon-based process; a light modulator 300 formed on the silicon substrate 100 using a silicon-based process, the light modulator 300 is used to generate photons to excite the emitter 200 to emit electrons; a collector 400 formed on the silicon substrate 100 using a silicon-based process, the collector 400 is used to excite the electrons emitted by the emitter 200.

[0038] On the one hand, since the entire device is prepared using a unified silicon-based process, the problem of inconsistency in the process preparation of the emitter 200 of the traditional cold cathode field emission is solved, the internal accuracy and consistency of the device are improved, and the reliability of the device is enhanced; on the other hand, based on the silicon-based process, the optical modulator 300 formed on the silicon substrate 100 is introduced to enhance the field emission efficiency of the emitter 200, offset the inconsistency of the distance between the tip of the emitter 200 and the collector 400 caused by the non-uniformity of the emitter 200, and increase the process redundancy of the cold cathode emission electrode, so that the device does not need to rely entirely on the field emission principle to generate electrons, thereby reducing the load of field emission and further enhancing the reliability of the device.

[0039] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0040] First of all, the term "and / or" in this article is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can mean: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in this article generally indicates that the associated objects before and after are in an "or" relationship.

[0041] In addition, the “inside” and “outside” that appear in the text are inside and outside in the conventional sense, which are for the convenience of clear description and are not any limitation.

[0042] Through the analysis of the existing technology, it can be seen that traditional power devices rely on PN to bear bias voltage. A large bias voltage requires a large drift area, which leads to an increase in on-resistance, thereby affecting the working efficiency of the device. Therefore, attempts are made to use the cathode field emission principle to improve the withstand voltage of power devices. However, due to the inconsistency of the process during the process, the cathode field emission array cannot achieve a unified field emission threshold, which in turn affects the power improvement of the entire device and the reliability of long-term operation. Therefore, attempts are made to use the principle of optical modulation to increase the field emission efficiency and increase the field emission threshold margin. However, the existing optical modulation methods all use optical fiber, carbon nanotubes and other technologies to introduce external light sources, which greatly affects its integration and modulability. Therefore, it is not possible to mass produce.

[0043] Embodiment 1

[0044] like Figure 1 As shown, the present application provides a power device through an embodiment, including at least one vacuum-packaged unit structure; wherein the unit structure includes:

[0045] Silicon substrate 100;

[0046] An emitter 200 formed on the silicon substrate 100 by using a silicon-based process;

[0047] A light modulator 300 is formed on the silicon substrate 100 by using a silicon-based process, and the light modulator 300 is used to generate photons to excite the emitter 200 to emit electrons;

[0048] The collector electrode 400 is formed on the silicon substrate 100 by using a silicon-based process, and the collector electrode 400 is used to excite and receive the electrons emitted by the emitter electrode 200 .

[0049] It should be noted that the power device of this embodiment generally includes a plurality of integrated unit structures, and the internal structure of a single unit structure is described first here.

[0050] See also Figure 1 , the silicon substrate 100 is located at the bottom, and the emitter 200, the collector 400 and the light modulator 300 are all formed on the silicon substrate 100 using a silicon-based process. On the one hand, due to the use of a unified silicon-based process, the problem of inconsistency in the process preparation of the emitter 200 of the traditional cold cathode field emission is solved, the internal precision and consistency of the device are improved, and the reliability of the device is enhanced. On the other hand, during operation, the emitter 200 and the collector 400 stimulate the emitter 200 to emit electrons through the electric field effect, and the collector 400 receives the electrons; at the same time, the light modulator 300 stimulates the emitter 200 to emit electrons through the photoelectric effect, supplementing the electric field effect, so that the device does not need to rely entirely on the field emission principle to generate electrons, increase the process redundancy of the cold cathode emission electrode, reduce the load of field emission, and enhance the reliability of the device. In addition, since the light modulator 300 uses optical modulation, this increases the modulation frequency, which can achieve high-frequency response, or even high-frequency and high-power response.

[0051] In addition, the optical modulator 300 can also increase the field emission threshold margin through the supplementary effect of the photoelectric effect on the field emission, so that the field emission array can still work normally under the assistance of light when the emission threshold is not uniform, which is beneficial to the array integration of the unit structure, thereby improving the power of the device and the reliability of long-term operation. The optical modulator 300 is formed on the silicon substrate 100 using a silicon-based process, which can achieve self-luminescence, without the need for external optical fiber or carbon nanotube technology to introduce external light sources, and also forms the necessary conditions for large-scale integration.

[0052] As an alternative structure, see Figure 2 The unit structure further includes: a gate 500 formed on the silicon substrate 100 using a silicon-based process, and the gate 500 is used to generate an electric field to excite the emitter 200 to emit electrons.

[0053] In this structure, the gate 500 is located between the collector 400 and the emitter 200, and is used to generate an electric field to stimulate the emitter 200 to emit electrons, while the collector 400 is used to receive electrons. The benefit of adding the gate 500 is to increase the field emission modulation efficiency. In addition to using the collector 400 to generate the field emission electric field, the device uses the gate 500 that is closer to the emitter to increase the modulation electric field, so that the electric modulation electrode that complements the optical modulation can be realized. In addition, the control of the two modulation ends can increase the reliability of the device, so that both control parameters do not need to work under extreme conditions.

[0054] It should be noted that when the gate 500 is present, the photoelectric effect compensates for the inconsistency of the distance between the tip of the emitter 200 and the gate 500 .

[0055] In this embodiment, the vacuum packaging pressure is 10 -6 Pa~10Pa. The reason for setting this range is that the electrons of the device have to travel a distance from the emitter 200 to the collector 400. If this distance is full of air, the electrons will collide with the gas atoms in the air, which will affect the electrons from reaching the collector 400. Therefore, the necessary vacuum condition is a requirement to ensure the normal operation of the device. In addition, according to different processing techniques, the distance between the gate 500 and the emitter 200, or the collector 400 and the emitter 200 is different. Therefore, in order to achieve the field emission electric field, the applied field emission voltage is proportional to the emission distance and inversely proportional to the pressure of the vacuum chamber. Therefore, the pressure has a certain range. The lower limit of the gas pressure is generally limited by the manufacturing process capability, and the high pressure limit is determined by the device reliability. When the field emission voltage is lower than 30V and the emission efficiency is 1%, the pressure can be up to 10Pa.

[0056] After the overall structure of the unit structure is clear, the specific structures of the light modulator 300 and the emitter 200 are described below.

[0057] See also Figure 1 and 2In this embodiment, the light modulator 300 is a LED structure with lateral light emission, which is convenient for sending photons to the emitter 200 located on the side. The type of light source can be selected as needed, as long as it can produce a photoelectric effect and excite the emitter to emit electrons. For example, different wavelengths of light-emitting LEDs can be processed according to different metal types of the emitter 200 (different work functions); illustratively, the light modulator 300 is an ultraviolet LED. The shorter wavelength of ultraviolet light can produce a photoelectric effect more effectively. Specifically, the ultraviolet LED includes an N-type semiconductor material, a P-type semiconductor material, and a resonant cavity formed by the N-type semiconductor material and the P-type semiconductor material. The semiconductor material used for the light modulator can be selected as needed, for example, an InGaN / AlGaN structure. illustratively, the N-type semiconductor material and the P-type semiconductor material are gallium nitride, indium gallium nitride, and aluminum gallium nitride. The reason for choosing gallium nitride, indium gallium nitride, and aluminum gallium nitride here is that the wide bandgap width is conducive to the formation of ultraviolet light with shorter wavelength, the direct band gap is conducive to high light emission efficiency, and the silicon-based gallium nitride LED structure and process are very mature.

[0058] In the specific implementation process, the ultraviolet LED can be connected to the electrode and the light intensity can be controlled by voltage to supplement the efficiency of field emission.

[0059] See also Figure 3 In this embodiment, the emitter 200 includes a silicon-based micro-tip structure 210 and a metal layer 200 covering the silicon-based micro-tip structure 210. The metal layer 200 can be selected as needed, such as molybdenum. The metal layer 200 is attached to the silicon-based micro-tip structure 210, or is directly formed by etching the metal layer 200.

[0060] It should be noted that, in this embodiment, the silicon-based process refers to a standard processing and manufacturing process using a silicon wafer as a substrate. In the specific implementation process, the unit structure of this embodiment can be prepared by the following method:

[0061] 1. Epitaxially grow gallium nitride material on a silicon substrate 100 to prepare a light-emitting diode, wherein the cathode of the light-emitting diode is connected to the substrate, and the anode is led out as a light modulation electrode of a power device;

[0062] 2. A molybdenum tip emitter is made by the Spindt method next to the light-emitting diode, or a silicon tip emitter 200 is made by an oxidation sharpening process. The emitter 200 is partially connected to the silicon substrate 100 to form an emission structure of the device;

[0063] 3. Evaporating metal on another silicon substrate to form a collector electrode 400;

[0064] 4. The collector electrode 400 is combined with other prepared parts in a vacuum environment by a silicon wafer bonding process to form a collecting electrode while providing a bonding cover plate 600 in a vacuum environment; wherein the metal surface of the collector electrode 400 is bonded to other parts, and the collector electrode 400 can also be formed by bonding a silicon wafer without evaporated metal;

[0065] 5. Each electrode is brought out through silicon processing technology for subsequent packaging.

[0066] After understanding the specific structure of a single unit structure, the working principle of the unit structure is explained below:

[0067] Figure 1 and Figure 2 It is the unit structure of two power devices. Figure 1 yes Figure 2 A simplification of the structure, Figure 1 The modulator of the device only has the light modulation provided by the light modulator 300, and the field emission electric field is provided by the collector 400. The electric field provided by the collector 400 meets the minimum field emission electric field condition in the device structure array, that is, it provides a basic electric field. Then, the light field provided by the light modulator 300 helps the device to excite the emitter electrons. The excited electrons are received by the collector 400, and the amount of received electrons is modulated and controlled by the light modulator 300. Figure 2 The device is modulated by light provided by the light modulator 300 and the electric field provided by the gate 500, so Figure 2 Since the voltage of the collector 400 no longer provides a field emission electric field, it can be appropriately reduced according to the circuit operation requirements, or a higher collection voltage can be achieved by increasing the distance from the collector 400 to the emitter 200. In addition, the control of the two modulation ends can increase the reliability of the device, so that both control parameters do not need to work under extreme conditions. The silicon substrate 100 and the emitter 200 are interconnected structures, which are the emitter (cathode) of the device. The negative electrode of the light modulator 300 is connected to the structures 100 and 200, and the positive electrode of the light modulator 300, that is, the light modulator, is separately led out. The collector 400 and the gate 500 are also separately led out to form the collector 400 or the electric modulator, respectively.

[0068] As mentioned above, in this embodiment, the power device generally includes multiple integrated unit structures. After the specific structure and working principle of a single unit structure are clear, after the unit structure preparation process is completed, multiple unit structures can be arranged in an array according to power requirements and then integrated. The following provides an implementation scheme for unit structure integration.

[0069] See also Figure 4As an optional implementation, the power device includes at least two unit structures, and the two unit structures are mirror-integrated along the light modulator 300. Specifically, a bonding cover plate 600 is also formed on the two unit structures mirror-integrated along the light modulator 300. Figure 4 In the structure, the gate 500 is not formed, and the Figure 1 The unit structure is integrated. Since the collector electrode 400 generates a field emission electric field after integration, the light modulator 300 forms a photoelectric modulator, and the collection current change of the device is controlled by the light modulator. In addition, the array structure is conducive to forming a replicable array structure and forming a high-power device. Therefore, it can be referred to Figure 4 An integration method is used to integrate several unit structures into an array, thereby improving the power of the overall device.

[0070] The technical solutions in the above embodiments of the present application have at least the following technical effects or advantages:

[0071] The power device of this embodiment includes a vacuum-packaged unit structure, including: a silicon substrate 100; an emitter 200 formed on the silicon substrate 100 using a silicon-based process; a light modulator 300 formed on the silicon substrate 100 using a silicon-based process, the light modulator 300 is used to generate photons to excite the emitter 200 to emit electrons; a collector 400 formed on the silicon substrate 100 using a silicon-based process, the collector 400 is used to excite the electrons emitted by the emitter 200. On the one hand, since the entire device is prepared using a unified silicon-based process, the problem of inconsistency in the process preparation of the emitter 200 of the traditional cold cathode field emission is solved, the internal accuracy and consistency of the device are improved, and the reliability of the device is enhanced; on the other hand, based on the silicon-based process, the optical modulator 300 formed on the silicon substrate 100 is introduced to enhance the field emission efficiency of the emitter 200, offset the inconsistency of the distance between the tip of the emitter 200 and the collector 400 caused by the non-uniformity of the emitter 200, and increase the process redundancy of the cold cathode emission electrode, so that the device does not need to rely entirely on the field emission principle to generate electrons, thereby reducing the load of field emission and further enhancing the reliability of the device.

[0072] Embodiment 2

[0073] Based on the same inventive concept as in Example 1, see Figure 5 This embodiment provides a method for preparing a power device, the method being used to prepare the unit structure in the first embodiment; the method comprising:

[0074] S102, preparing a silicon substrate;

[0075] S104, epitaxially preparing a light modulator on a silicon substrate, wherein a cathode of the light modulator is connected to the silicon substrate, and a cathode of the light modulator is led out as a light modulation control electrode;

[0076] S106, preparing an emitter on the silicon substrate next to the light modulator;

[0077] S108, combining the prepared collector electrode with the silicon substrate through a silicon wafer bonding process to form a unit structure.

[0078] It should be noted that the specific implementation of this embodiment please refer to Example 1, which will not be repeated here.

[0079] Although the preferred embodiments of the present invention have been described, those skilled in the art may make other changes and modifications to these embodiments once they have learned the basic creative concept. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention.

[0080] Obviously, those skilled in the art can make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A power device, characterized in that: A unit structure comprising at least one vacuum package; wherein the unit structure comprises: Silicon substrate; An emitter is formed on the silicon substrate by using a silicon-based process; the silicon-based process for forming the emitter is an oxidation sharpening process; A light modulator is formed on the silicon substrate by using a silicon-based process, wherein the light modulator is a self-luminous ultraviolet LED structure that emits light laterally, and the light modulator is used to generate photons to excite the emitter to emit electrons; A collector electrode is formed on the silicon substrate by using a silicon-based process, the collector electrode is used to receive electrons emitted by the emitter electrode, and the silicon-based process for forming the collector electrode is an evaporation process; A gate is formed on the silicon substrate using a silicon-based process. The gate is located between the collector and the emitter and is used to generate an electric field to excite the emitter to emit electrons. Adding a gate can increase field emission modulation efficiency.

2. The power device according to claim 1, characterized in that: The ultraviolet LED includes an N-type semiconductor material, a P-type semiconductor material, and a resonant cavity formed by the N-type semiconductor material and the P-type semiconductor material.

3. The power device according to claim 2, characterized in that: The N-type semiconductor material and the P-type semiconductor material are gallium nitride, indium gallium nitride or aluminum gallium nitride.

4. The power device according to claim 1, characterized in that: The emitter includes a silicon-based micro-tip structure and a metal layer covering the silicon-based micro-tip structure.

5. The power device according to claim 1, characterized in that: The vacuum packaging pressure is 10 -6 Pa~10Pa.

6. The power device according to any one of claims 1 to 5, characterized in that: The power device comprises at least two of the unit structures, and the two unit structures are mirror-integrated along the optical modulation pole.

7. A method for preparing a power device, characterized in that: The method is used to prepare a power device according to any one of claims 1 to 6; the preparation method comprises: preparing a silicon substrate; Epitaxially preparing a light modulator on a silicon substrate, wherein the negative electrode of the light modulator is connected to the silicon substrate, and the positive electrode of the light modulator is led out as a light modulation control electrode; Preparing an emitter on the silicon substrate next to the light modulator; The prepared collector electrode is combined with the silicon substrate through a silicon wafer bonding process to form a unit structure.

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