JPH07193087A - Microwave transistor - Google Patents

Abstract

PURPOSE:To avoid the deterioration of the radio frequency characteristics caused by a phase difference by a method wherein difference in distances of respective routes from a gate feeding end to a drain feeding end is made to be small enough without increasing an occupying area and a parasitic capacitance. CONSTITUTION:A microwave transistor in which a gate feeding end 6 is connected to the end of a gate bus electrode 4 and a drain feeding end 7 is connected to the end of a drain bus electrode 5 opposite to the gate feeding end 6 is obtained. With this constitution, the difference in distances of respective routes from the gate feeding end 6 to the drain feeding end 7 is made to be small enough to avoid the deterioration of the radio frequency characteristics caused by a phase difference without increasing an occupying area and a parasitic capacitance.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, particularly a microwave transistor.

[0002]

2. Description of the Related Art A planar structure of a conventional microwave transistor will be described below with reference to the drawings.

FIG. 2 is a plan view of a conventional microwave transistor having a comb structure. In FIG. 2, 1 is a source electrode, 2 is a drain electrode, 3 is a gate electrode, 4 is a gate bus electrode, 5 is a drain bus electrode, 6 is a gate power supply end, and 7
Is a drain power supply terminal, and 8 is a unit transistor. As shown in the figure, the gate feeding end 6 is connected to the central portion on one side of the gate bus electrode 4, and the plurality of gate electrodes 3 are connected to the other side. Similarly, in the central portion of the drain bus electrode 5 on one side, the drain feeding end 7
And a plurality of drain electrodes 2 are connected to the other side. And the drain electrode 2, the source electrode 1,
Further, the unit transistor 8 is constituted by the gate electrode 3 sandwiched therebetween, and a plurality of unit transistors 8 are arranged adjacent to each other in the direction perpendicular to the longitudinal direction of the source, drain and gate electrodes.

FIG. 3 is a plan view of a conventional dendritic microwave transistor. 3 is different from FIG. 2 in that the first-stage connection wiring 9, the first-stage fingers 10 and 2,
The point is that the stage connection wiring 11, the second stage finger 12, and the stage 3 connection wiring 13 are provided. As shown in FIG. 3, the gate electrodes 3 are sequentially combined two by two next to each other.
They are connected by the stage connection wiring 9. A first-stage finger 10 is connected to the center of the first-stage connection wiring 9. 1
The second-stage fingers 10 are sequentially combined two by two next to each other and connected to the second-stage connection wiring 11. A second-stage finger 12 is connected to the center of the second-stage connection wiring 11, and they are connected by a third-stage connection wiring 13. Three
The gate feeding end 6 is connected to the central portion of the stage connection wiring 13. In this way, the first-stage connection wiring 9, the first-stage finger 10, the second-stage connection wiring 11, the second-stage finger 12, and the third-stage connection wiring 13 have a tournament shape, that is, a dendritic input branch portion 14. Is formed. Similarly, the output side 15 is formed on the drain side.

[0005]

In the conventional microwave transistor having a comb structure shown in FIG. 2, the distance between the gate feeding end 6 and the gate electrode 3 varies depending on the position of each gate electrode. Similarly, the distance between the drain feeding end 7 and the drain electrode 2 also differs depending on the position of each drain electrode. Therefore, between the signals supplied to the gate power feeding end 6 and reaching the drain power feeding end 7 from the gate electrode 3 via the drain electrode 2, there is a phase difference according to the distance of the route through which each signal passes. . This phase difference increases as the frequency becomes higher. Therefore, when the microwave transistor having a comb structure is operated at a high frequency, the signals that have passed through the respective paths are combined with a phase difference at the drain feeding end 7, resulting in high frequency characteristics such as gain reduction and waveform distortion. There was a problem of deterioration.

The problem of the phase difference has been avoided by adopting a structure including the input / output branch portion of the dendritic structure shown in FIG. That is, in this structure, the gate feeding end 6
The distance difference between the respective paths from the gate electrode 3 to each of the gate electrodes 3 is sufficiently small, and the distance difference between the respective paths from the drain electrode 2 to each of the drain feeding ends 7 is also sufficiently small. Therefore, the signals propagating through the respective paths are combined at the drain feeding end 7 in the same phase, and the high frequency characteristics such as gain reduction and waveform distortion do not occur.

However, in the microwave transistor having the dendritic structure, there is a problem that the input branch section 14 and the output branch section 15 increase the occupied area and hinder high integration of the circuit. Further, when the microstrip structure is provided with the ground plane on the back surface of the substrate, there is a problem that the parasitic capacitance generated between the input branch section and the output branch section and the ground plane deteriorates the high frequency characteristics of the transistor. Furthermore, the numbers of gate electrodes 3 and drain electrodes 2 are
There was a restriction that it must be a power of two.

[0008]

A microwave transistor of the present invention comprises a plurality of unit transistors each having a drain electrode, a source electrode, and a gate electrode sandwiched therebetween, in a direction perpendicular to the longitudinal direction of the gate electrode. Adjacent to each other, connect the plurality of gate electrodes to one side of the gate bus electrode, connect the gate feeding end to the opposite side, and similarly connect the plurality of drain electrodes to one side of the drain bus electrode. , A comb-shaped structure in which a drain feeding end is connected to the opposite side, and the gate feeding end is connected to one end of the gate bus electrode, and the drain feeding end is the gate feeding of the drain bus electrode. It has a configuration in which it is connected to the end opposite to the end.

[0009]

With the gate feeding end as the starting point, the difference in distance between the gate electrode and the drain electrode via the drain electrode to the drain feeding end can be made sufficiently small. Therefore, the drain feeding end between the signals propagating through the respective paths can be reduced. Since the phase difference in 1 can be sufficiently reduced, it is possible to sufficiently reduce deterioration of high frequency characteristics such as gain reduction and waveform distortion due to combining signals having a phase difference. Further, similarly to the microwave transistor having a dendritic structure capable of sufficiently reducing the phase difference, the occupied area is small and the circuit can be highly integrated. Further, in the case of the microstrip structure having the ground plane on the back surface of the substrate, there is no dissolution that occurs between the input / output branch section and the ground plane, which is advantageous in terms of high frequency characteristics as compared with the dendritic structure.
Further, the number of gate and drain electrodes is not limited to a power of 2 and can be freely selected.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a microwave transistor according to an embodiment of the present invention.

The microwave transistor of this embodiment comprises a source electrode 1, a drain electrode 2, a gate electrode 3, a gate bus electrode 4, a drain bus electrode 5, a gate feeding end 6 and a drain feeding end 7. As shown in the figure, the gate power supply end 6 is connected to one end of the gate bus electrode 4, and the plurality of gate electrodes 3 are connected to the other end. A drain power supply end 7 is connected to one end of the drain bus electrode 5 opposite to the gate power supply end 6, and a plurality of drain electrodes 2 are connected to the other side. There is. The drain electrode 2, the source electrode 1, and the gate electrode 3 sandwiched therebetween form a unit transistor 8, and a plurality of unit transistors 8 are arranged adjacent to each other in the direction perpendicular to the longitudinal direction of the source, drain and gate electrodes. Has been done.

In this embodiment, the method of connecting the plurality of source electrodes 1 is not limited. As for this, a source island via hole structure connected to the ground plane formed on the back surface through a via hole, an air bridge structure connected to the ground plane formed on the front surface through an air bridge, and the like are possible.

[0013]

As described above, in the microwave transistor of the present invention, the gate feeding end and the drain electrode end are connected to the opposite ends of the gate bus electrode and the drain bus electrode, respectively. This makes it possible to sufficiently reduce the difference in distance between the gate power supply end and the route from the gate electrode to the drain power supply end via the drain electrode. Therefore, the phase difference at the drain power supply end between the signals supplied to the gate power supply end and passing through each unit transistor can be made sufficiently small. Therefore, gain reduction and waveform distortion caused by combining signals having a phase difference without increasing the occupied area or the parasitic capacitance and limiting the number of gate and drain electrodes to a power of 2 There is an effect that the deterioration of the high frequency characteristics can be sufficiently reduced.

[Brief description of drawings]

FIG. 1 is a plan view of a microwave transistor according to an embodiment of the present invention.

FIG. 2 is a plan view of a conventional microwave transistor having a comb structure.

FIG. 3 is a plan view of a conventional microwave transistor having a dendritic structure.

[Explanation of symbols]

 1 Source Electrode 2 Drain Electrode 3 Gate Electrode 4 Gate Bus Electrode 5 Drain Bus Electrode 6 Gate Feeding End 7 Drain Feeding End 8 Unit Transistor 9 1st Stage Connection Wiring 10 1st Stage Finger 11 2nd Stage Connection Wiring 12 2nd Stage Finger 13 Third stage connection wiring 14 Input branch section 15 Output branch section

Claims (1)

[Claims] 1. A plurality of unit transistors each having a drain electrode, a source electrode, and a gate electrode sandwiched therebetween are arranged adjacent to each other in a direction perpendicular to a longitudinal direction of the gate electrode, and a gate bus is provided. The plurality of gate electrodes are connected to one side of the electrode, the gate feeding end is connected to the opposite side, the plurality of drain electrodes are connected to one side of the drain bus electrode, and the drain feeding end is connected to the opposite side. A comb-shaped microwave transistor to be connected, wherein the gate feeding end is connected to one end of the gate bus electrode, and the drain feeding end is the opposite side of the drain bus electrode from the gate feeding end. A microwave transistor characterized in that it is connected to an end of a microwave transistor.