CN107680964A - A kind of microwave power amplifier for improving power cell temperature homogeneity - Google Patents

Abstract

The invention provides a kind of microwave power amplifier for improving power cell temperature homogeneity.The microwave power amplifier for improving power cell temperature homogeneity includes the multiple power cells being arranged in parallel, each power cell includes multiple transistors, and the colelctor electrode of transistor passes through the electric connection of the first connection unit in the two neighboring power cell；First connection unit includes the first metal layer, insulating medium layer and the second metal layer set gradually from bottom to top, the first layer metal of first connection unit is connected with drop thermal, and the second metal layer of first connection unit is connected with the colelctor electrode of transistor in the two neighboring power cell；In first connection unit, according to the Temperature Distribution direction of transistor in the power cell, the area of the second metal layer reduces direction along temperature and is gradually reduced.

Description

A Microwave Power Amplifier with Improved Temperature Uniformity of Power Unit

technical field

The invention belongs to the technical field of microwave power amplifiers, in particular to a microwave power amplifier for improving the temperature uniformity of a power unit.

Background technique

Modern communications require microwave power amplifiers to be able to provide high-power output, and at the same time have good linearity and efficiency. However, for power tubes, due to the low heat dissipation coefficient of the substrate, the high-power output increases the thermal effect of the transistor and forms a high-temperature active device. At this time, the performance of the transistor is degraded, and the linearity and efficiency deteriorate. Even under higher temperature conditions, Its reliability will be affected. Therefore, in order to obtain a high-performance power amplifier, the bottleneck effect of thermal effects should be solved.

The usual practice in the prior art is to improve the heat dissipation environment and reduce the heat source, such as starting from the layout of the amplifier, optimizing the heat dissipation environment, changing the finger spacing, finger length, etc. to obtain a power unit with uniform temperature distribution, and using the ballast resistor to change the thermoelectric The negative feedback between them stabilizes the circuit. It is of great significance to obtain a low-temperature transistor under certain power consumption conditions, but its heat dissipation effect is not good.

Contents of the invention

The object of the present invention is to provide a microwave power amplifier that improves the temperature uniformity of the power unit in view of the defects in the prior art.

The technical solution of the present invention is as follows: a microwave power amplifier for improving the temperature uniformity of a power unit includes a plurality of power units arranged in parallel, each of the power units includes a plurality of transistors, and the transistors in two adjacent power units The collectors are electrically connected through the first connection unit; the first connection unit includes a first metal layer, an insulating medium layer and a second metal layer arranged in sequence from bottom to top, and the first layer of metal in the first connection unit The second metal layer of the first connection unit is connected to the collectors of the transistors in two adjacent power units; in the first connection unit, according to the transistors in the power unit The temperature distribution direction, the area of the second metal layer gradually decreases along the temperature decreasing direction.

Preferably, a plurality of transistors in the power unit are arranged side by side in a straight line, and along the arrangement direction of the plurality of transistors, the area of the second metal layer gradually decreases from the middle to both sides.

Preferably, along the arrangement direction of the plurality of transistors, the second metal layer is distributed in a ladder shape from the middle to both sides.

Preferably, the first metal layer and the second metal layer of the first connection unit are complementary structures.

Preferably, the emitters of the transistors in two adjacent power units are electrically connected through a second connection unit, the second connection unit is a first metal layer, and the first metal layer of the second connection unit is connected to the lower The thermal device is connected.

Preferably, a plurality of back holes are arranged below the first connection unit and the second connection unit, and the back holes of the first connection unit and the second connection unit communicate with the heat reducing device .

Preferably, the back holes are arranged in the shape of a truncated cone, and the cross-sectional area of the back holes gradually increases from top to bottom.

Preferably, the first metal layer and the second metal layer are made of the same material.

Preferably, the insulating medium layer is made of Si ₃ N ₄ .

Preferably, the microwave power amplifier is an InGaP/GaAs HBT power device, a GaN power device or an LDMOS power device.

The technical scheme provided by the invention has the following beneficial effects:

The shortest path of the microwave power amplifier heat source for improving the temperature uniformity of the power unit is used for heat dissipation, and the collector metal is introduced to provide a heat dissipation path to the ground. By increasing this heat dissipation path, the temperature of the power unit is reduced and improved, thereby obtaining high efficiency and high linearity The amplifier has a simple layout structure and is easy to implement.

At the same time, the second metal layer in the first connection unit can provide a lateral heat dissipation channel for the power unit, thereby reducing the temperature of the power amplifier, so the second metal layer provides a wider metal heat dissipation path for the transistor located in the middle, thereby improving the temperature of the power unit The uniformity of distribution reduces the lateral coupling strength;

In addition, the first metal layer and the second metal layer of the first connection unit are complementary structures, which can greatly reduce the overlapping area between the first metal layer and the second metal layer, and reduce the electrical influence between the two. performance impact.

Description of drawings

FIG. 1 is a schematic structural diagram of a microwave power amplifier for improving temperature uniformity of a power unit provided by an embodiment of the present invention;

Fig. 2 is the sectional schematic diagram of AA ' direction in the microwave power amplifier that improves power cell temperature uniformity shown in Fig. 1;

Fig. 3 is the sectional schematic diagram of BB' direction in the microwave power amplifier that improves power cell temperature uniformity shown in Fig. 1;

Fig. 4 is the sectional schematic diagram of CC ' direction in the microwave power amplifier that improves power cell temperature uniformity shown in Fig. 1;

Fig. 5 is a schematic cross-sectional view of the DD' direction in the microwave power amplifier for improving the temperature uniformity of the power unit shown in Fig. 1 .

detailed description

In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described here are only used to explain the present invention, not to limit the present invention.

Unless the context clearly states otherwise, the number of elements and components in the present invention can exist in a single form or in multiple forms, and the present invention is not limited thereto. Although the steps in the present invention are arranged with labels, they are not used to limit the order of the steps. Unless the order of the steps is clearly stated or the execution of a certain step requires other steps as a basis, the relative order of the steps can be adjusted. It can be understood that the term "and/or" used herein refers to and covers any and all possible combinations of one or more of the associated listed items.

The microwave power amplifier provided by the present invention may be an InGaP/GaAs HBT power device, a GaN power device or an LDMOS power device, and the like.

As shown in Figures 1-5, the microwave power amplifier provided by the embodiment of the present invention includes a first power unit 10, a second power unit 20, and a third power unit 30 arranged in parallel, and the first power unit 10 includes A total of 8 transistors T1-T8 arranged in a row, the second power unit 20 includes a total of 8 transistors T9-T16 arranged side by side in a straight line, and the third power unit 30 includes T17-T24 arranged side by side in a straight line There are 8 transistors in total, the collector is the collector of each transistor, and the emitter is the emitter. The collectors of the transistors in each of the power units are electrically interconnected, and the emitters of the transistors in each of the power units are electrically interconnected.

Optionally, in other alternative embodiments, the microwave power amplifier may include two, four or at least five power units, and the number of transistors in each power unit is not limited to 8, and may also be Other suitable numbers need to be selected according to actual design needs, which is not limited in the present invention. It should be noted that the transistors in each power unit are arranged side by side in a straight line.

Wherein, in this embodiment, the collectors of the transistors (T1-T8) in the first power unit 10 and the collectors of the transistors (T9-T16) in the second power unit 20 are electrically connected through the first connection unit 40, and the second The emitters of the transistors ( T9 - T16 ) in the power unit 20 and the emitters of the transistors ( T17 - T24 ) in the third power unit 30 are electrically connected through the second connection unit 50 .

As shown in FIG. 2 , the first connection unit 40 includes a first metal layer 41 (M1 metal layer), a second metal layer 42 (M2 metal layer), and an insulating dielectric layer 43 stacked in order from top to bottom. Wherein, in this embodiment, the material of the first metal layer 41 and the second metal layer 42 are the same, only different in thickness, but in other implementation manners, they can also be set as metal layers of different materials; the material of the insulating medium layer 43 is Si ₃ N ₄ .

Because the thermal conductivity of metal is very large, such as silver is 420W/mK, and semiconductor materials such as GaAs have a relatively small heat dissipation coefficient (GaAs is 46W/mK), so the first metal layer 41 and the second metal layer 42 can be the first connection. Unit 40 provides a fast heat dissipation path.

The first metal layer 41 of the first connection unit 40 communicates with the heat reducing device (not shown in the figure), and the second metal layer 42 of the first connection unit 40 is connected with the first power unit 10 and the second power unit respectively. The collector of 20 is connected. Moreover, in the first connection unit 40 , according to the temperature distribution direction of the transistors in the power unit, the area of the second metal layer 42 gradually decreases along the temperature decreasing direction.

As we all know, in the geometric structure of microwave power amplifiers, the size of the heat source should be concentrated at the peak electric field. Under the normal bias of the power amplifier, the bias voltage of the collector junction is the largest and the heat is the most severe. Therefore, if the corresponding heat dissipation treatment is performed on the collector, it can be more Effectively improve the cooling effect. However, considering that the collector cannot be electrically connected to the ground, in this embodiment, indirect heat dissipation is adopted between adjacent first power units 10 and second power units 20 through the second metal layer 42 .

In addition, in this embodiment, the eight transistors in each power unit are respectively arranged side by side along a straight line. Due to thermal coupling, the temperature at the middle of each power unit is higher than that at the edge. In fact, according to the heat distribution theory, the temperature distribution in each power unit gradually decreases from the middle to both ends, and presents a symmetrical bell-shaped distribution.

Therefore, considering the non-uniform temperature distribution caused by the lateral thermal coupling effect between transistors, and in order to further reduce the non-uniform temperature distribution in the power unit, in the first connecting unit 40, along the In the arrangement direction of multiple transistors, the area of the second metal layer 42 gradually decreases from the middle to both sides. In this embodiment, the second metal layer 42 can provide a lateral heat dissipation channel for the power unit, thereby reducing the temperature of the power amplifier. Therefore, the second metal layer 42 provides a wider metal heat dissipation path for the transistor located in the middle, thereby improving the temperature of the power unit. The uniformity of distribution reduces the lateral coupling strength. Preferably, along the arrangement direction of the plurality of transistors, the second metal layer 42 is distributed in a ladder shape from the middle to both sides.

Moreover, a number of first back holes 44 are provided under the first metal layer 41 in the first connection unit 40 , and the first connection unit 40 communicates with the heat reducing device through the first back holes 44 . Preferably, the first back hole 44 is set in the shape of a conical cone, and the cross-sectional area of the first back hole 44 gradually increases from top to bottom. In this embodiment, there are two first back holes 44, respectively C1 , C2; Optionally, in other alternative embodiments, the number and shape of the first back holes 44 can also be designed as other numbers and shapes.

In addition, since the collector cannot be connected to the ground, an insulating dielectric layer 43 is provided between the first metal layer 41 and the second metal layer 42 in the first connection unit 40 . Since a metal-dielectric-metal parasitic capacitance is formed between the first metal layer 41, the second metal layer 43, and the insulating dielectric layer 42, in this embodiment, the first metal layer of the first connection unit 40 41 and the second metal layer 42 are complementary structures, so that the overlapping area between the first metal layer 41 and the second metal layer 42 can be greatly reduced, and the influence of both on the electrical performance can be reduced. Moreover, for the first metal layer 41 , part of the longitudinal heat flow can still be dissipated to the ground through the first back hole 44 by means of the first metal layer 41 to reduce the overall temperature.

As shown in FIG. 2 , the second connection unit 50 includes a first metal layer 51 , and the first metal layer 51 of the second connection unit 50 communicates with the heat reducing device.

Moreover, a number of second back holes 52 are provided under the first metal layer 51 in the second connection unit 50 , and the second connection unit 50 communicates with the heat reducing device through the second back holes 52 . Preferably, the second back hole 52 is arranged in the shape of a conical cone, and the cross-sectional area of the second back hole 52 gradually increases from top to bottom. In this embodiment, there are two second back holes 52, respectively C3 , C4; Optionally, in other alternative embodiments, the number and shape of the second back holes 52 can also be designed as other numbers and shapes.

It will be apparent to those skilled in the art that the invention is not limited to the details of the above-described exemplary embodiments, but that the invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Accordingly, the embodiments should be regarded in all points of view as exemplary and not restrictive, the scope of the invention being defined by the appended claims rather than the foregoing description, and it is therefore intended that the scope of the invention be defined by the appended claims rather than by the foregoing description. All changes within the meaning and range of equivalents of the elements are embraced in the present invention. Any reference sign in a claim should not be construed as limiting the claim concerned.

In addition, it should be understood that although this specification is described according to implementation modes, not each implementation mode only contains an independent technical solution, and this description in the specification is only for clarity, and those skilled in the art should take the specification as a whole , the technical solutions in the various embodiments can also be properly combined to form other implementations that can be understood by those skilled in the art.

Claims (10)

1. A microwave power amplifier for improving the temperature uniformity of the power unit, characterized in that: comprise a plurality of power units arranged in parallel, each of the power units comprises a plurality of transistors, the transistors in the adjacent two power units The collectors are electrically connected through the first connecting unit; The first connection unit includes a first metal layer, an insulating medium layer, and a second metal layer arranged sequentially from bottom to top, the first metal layer of the first connection unit communicates with the heat reducing device, and the first connection The second metal layer of the unit is connected to the collectors of transistors in two adjacent power units; In the first connection unit, according to the temperature distribution direction of the transistors in the power unit, the area of the second metal layer gradually decreases along a temperature decreasing direction. 2. A microwave power amplifier for improving the temperature uniformity of the power unit according to claim 1, characterized in that: a plurality of transistors in the power unit are arranged side by side in a straight line, and along the arrangement direction of the plurality of transistors, The area of the second metal layer gradually decreases from the middle to both sides. 3. A microwave power amplifier for improving the temperature uniformity of the power unit according to claim 2, characterized in that: along the arrangement direction of the plurality of transistors, the second metal layer is distributed in a ladder shape from the middle to both sides . 4 . The microwave power amplifier for improving the temperature uniformity of the power unit according to claim 1 , wherein the first metal layer and the second metal layer of the first connection unit are complementary structures. 5. A microwave power amplifier for improving temperature uniformity of a power unit according to claim 1, characterized in that: the emitters of the transistors in two adjacent power units are electrically connected through a second connection unit, and the The second connection unit is the first metal layer, and the first metal layer of the second connection unit communicates with the heat reducing device. 6. A microwave power amplifier for improving the temperature uniformity of the power unit according to claim 5, characterized in that: there are a plurality of back holes arranged below the first connection unit and the second connection unit, so Both the first connection unit and the second connection unit communicate with the heat reducing device through the back hole. 7. A microwave power amplifier for improving the temperature uniformity of the power unit according to claim 6, characterized in that: the back holes are arranged in the shape of a circular frustum, and the cross-sectional area of the back holes gradually increases from top to bottom. increase. 8 . The microwave power amplifier for improving temperature uniformity of a power unit according to claim 1 , wherein the first metal layer and the second metal layer are made of the same material. 9 . The microwave power amplifier for improving the temperature uniformity of the power unit according to claim 1 , wherein the insulating medium layer is made of Si ₃ N ₄ . 10. A microwave power amplifier for improving the temperature uniformity of a power unit according to claim 1, wherein the microwave power amplifier is an InGaP/GaAs HBT power device, a GaN power device or an LDMOS power device.