A high-power internal matching circuit for suppressing strong electric field breakdown

Abstract

The present invention proposes a high-power internal matching circuit that suppresses strong electric field breakdown. A layer of passivation medium is grown on the surface of the ceramic internal matching circuit through a semiconductor processing technology. The passivation medium can effectively suppress the strong electric field breakdown phenomenon in the power tube internal matching circuit under ultra-large output power conditions, thereby greatly improving the reliability of high-power devices. The present invention is conducive to achieving continuous and stable operation of ultra-high power devices while ensuring that the radio frequency loss of the internal matching circuit is not increased and the impedance of the internal matching circuit is not changed. It has broad application prospects in the fields of radar, aerospace, etc.

Description

Technical Field

[0001] The invention relates to a high-power internal matching circuit for suppressing strong electric field breakdown, belonging to the technical field of microwave power devices. Background Art

[0002] With the rapid development of wireless communication technology, the first generation semiconductors represented by Ge and Si and the second generation semiconductors represented by GaAs can no longer fully meet the system's requirements for power amplifiers. The third generation semiconductor materials represented by GaN have the characteristics of wide bandgap, high electron mobility, high electron saturation rate, high breakdown voltage, high thermal conductivity, good chemical stability and strong radiation resistance. High electron mobility transistor (GaN HEMT) power devices have the advantages of high operating frequency, high breakdown voltage, high power density and high efficiency, and have gradually become ideal devices for microwave power devices and microwave monolithic integrated circuit applications.

[0003] In recent years, the demand for ultra-high power microwave power amplifiers has been increasing in the fields of radar, aerospace, etc. Ultra-high power microwave power amplifiers generally use large gate width tube cores to synthesize multiple tube cores to achieve ultra-high power output. When the output power reaches a certain intensity, the internal matching circuit of the power device will experience strong electric field air breakdown (commonly known as "sparking" phenomenon), which reduces the reliability of ultra-high power devices.

[0004] In the design of traditional internal matching circuits, in order to prevent air breakdown under ultra-large output power conditions, arc transitions are generally used when the circuit has corners to prevent charge concentration, thereby minimizing the electric field strength at the corners. However, due to limitations in processing accuracy and height differences in the circuit copper foil, strong electric fields may still occur locally, and the problem of air breakdown in circuits under high power conditions cannot be fundamentally solved. Summary of the invention

[0005] The purpose of the present invention is to solve the above-mentioned problems existing in the working process of the existing microwave power amplifier, and to propose a high-power internal matching circuit for suppressing strong electric field breakdown, which can effectively suppress the air breakdown phenomenon in the internal matching circuit under ultra-high power, thereby greatly improving the reliability of the operation of high-power devices.

[0006] The technical solution of the present invention is a high-power internal matching circuit for suppressing strong electric field breakdown, and its structure includes two ceramic substrates and a circuit layer, and the circuit layer is arranged on the upper surfaces of the two ceramic substrates. It is characterized in that a layer of passivation medium is grown on the non-bonded area of ​​the circuit layer surface by using semiconductor processing technology, and the passivation medium can improve the electric field breakdown strength, and can effectively reduce the strong electric field air breakdown phenomenon in the internal matching circuit under ultra-large output power conditions, thereby greatly improving the reliability of high-power device operation.

[0007] Furthermore, the ceramic substrate is made of alumina ceramic with a dielectric constant of 9.9 and a thickness of 380um and 635um.

[0008] Furthermore, the circuit layer is formed by copper plating and gold plating on the ceramic substrate, the thickness of the gold layer is 10um, and bonding areas are provided on the surface of the circuit layer, and resistors are used to isolate the bonding areas.

[0009] Furthermore, the passivation medium can fully or partially cover the circuit, that is, it can completely cover the internal matching circuit, leaving only the part that needs to be interconnected and bonded, or it can only cover the edge of the signal metal layer of the internal matching circuit; or according to the electric field simulation results, only cover the part where the electric field is strong and air breakdown is likely to occur. The thickness of the medium is generally 3-20um.

[0010] Furthermore, the thickness of the passivation medium can be any value, and the specific thickness value depends on the electric field strength when the circuit is actually working.

[0011] Furthermore, the passivation medium can be used in both the internal matching circuit of the power device and the matching capacitor of the internal matching power device.

[0012] Furthermore, the passivation medium can be a PI medium, SiO 2介质 Or other insulating media, among which PI media are coated and then baked at high temperature, and then photolithography is performed to achieve dielectric growth coverage; SiO2 media can be grown by PECVD or other methods.

[0013] Compared with the prior art, the advantages of the present invention are: by growing a layer of passivation medium on the designed structure of the internal matching circuit through semiconductor processing technology, the threshold of electric field breakdown in the circuit can be increased without increasing the RF loss of the internal matching circuit and changing the impedance of the internal matching circuit, thereby effectively suppressing the air breakdown phenomenon in the circuit under ultra-large output power conditions, and ultimately greatly improving the reliability of the operation of high-power devices; the circuit structure has high reliability, high production and processing precision, good consistency, and can be applied in large-scale batch production. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Attached Figure 1 It is a schematic structural diagram of a high-power internal matching circuit for suppressing strong electric field breakdown according to the present invention.

[0015] Attached Figure 2 It is a component composition diagram of a high-power internal matching circuit for suppressing strong electric field breakdown according to the present invention.

[0016] Attached Figure 3 It is a structural stereogram of a high-power internal matching circuit for suppressing strong electric field breakdown according to the present invention. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further described below in conjunction with the accompanying drawings. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements with the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended to be used to explain the present invention, but should not be construed as limiting the present invention.

[0018] In order to simplify the disclosure of the present invention, the parts and settings of specific examples are described below. Of course, they are only examples, and the purpose is not to limit the present invention. In addition, the present invention can repeat reference numbers and / or reference letters in different examples, and this repetition is for the purpose of simplicity and clarity, which itself does not indicate the relationship between the various embodiments and / or settings discussed. In addition, the present invention provides various specific examples of processes and materials, but those of ordinary skill in the art can appreciate the application of other processes and / or the use of other materials.

[0019] In the description of this specification, the description with reference to the terms "one embodiment", "certain embodiments", "illustrative embodiments", "examples", "specific examples" or "some examples" etc. means that the specific characteristic structures, materials or features described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific characteristic structures, materials or features described may be combined in any one or more embodiments or examples in a suitable manner.

[0020] The high-power internal matching circuit for suppressing strong electric field breakdown proposed by the present invention has a circuit structure designed as follows: Figures 1 to 3 shown. Figure 2 1 is a ceramic substrate of the internal matching circuit. The ceramic substrate 1 is made of alumina ceramic with a dielectric constant of 9.9 and a thickness of 380um and 635um. Copper and gold plating are performed on the ceramic substrate 1 to form a circuit layer 2. The thickness of the gold layer is 10um. Resistors are used to isolate the circuit layers 2 to improve circuit stability. Then, a passivation medium 3 is grown on the non-bonding area on the surface of the circuit layer 2 using a semiconductor processing technology. The passivation medium 3 can be PI, SiO2 or other insulating media, and the dielectric thickness is generally 3-20um.

[0021] The high-power internal matching circuit implemented by the technology of the present invention can effectively avoid the phenomenon of air breakdown in the circuit under high-power conditions without increasing the loss of the matching circuit and changing the circuit impedance, thereby achieving long-term stable operation of the high-power device.

[0022] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A high-power internal matching circuit for suppressing strong electric field breakdown, comprising two ceramic substrates and a circuit layer, wherein the circuit layer is arranged on the upper surfaces of the two ceramic substrates, and characterized in that: A layer of passivation medium is grown on the non-bonding area on the surface of the circuit layer using semiconductor processing technology.

2. A high-power internal matching circuit for suppressing strong electric field breakdown according to claim 1, characterized in that: The ceramic substrate is made of alumina ceramic with a dielectric constant of 9.9 and a thickness of 380um and 635um.

3. A high-power internal matching circuit for suppressing strong electric field breakdown according to claim 1, characterized in that: The circuit layer is formed by copper plating and gold plating on a ceramic substrate, the thickness of the gold layer is 10um, and bonding areas are provided on the surface of the circuit layer, and resistors are used to isolate the bonding areas.

4. A high-power internal matching circuit for suppressing strong electric field breakdown according to claim 1, characterized in that: The passivation medium fully or partially covers the circuit, specifically including: completely covering the internal matching circuit, leaving only the part that needs interconnection and bonding; or covering only the edge of the signal metal layer of the internal matching circuit; or covering only the part with strong electric field and prone to air breakdown according to the electric field simulation results.

5. A high-power internal matching circuit for suppressing strong electric field breakdown according to claim 1, characterized in that: The specific thickness value of the passivation medium depends on the electric field strength when the circuit is actually working.

6. A high-power internal matching circuit for suppressing strong electric field breakdown according to claim 1, characterized in that: The passivation medium is used in the internal matching circuit of the power device, or in the matching capacitor of the internal matching power device.

7. A high-power internal matching circuit for suppressing strong electric field breakdown according to claim 1, characterized in that: The passivation medium is a PI medium or a SiO2 medium, wherein the PI medium is coated and then baked at high temperature, and then photolithography is performed to achieve medium growth coverage; the SiO2 medium is grown by PECVD.

Images