JPH07226488A - High-frequency and high-output transistor - Google Patents

Abstract

PURPOSE:To provide a low-cost, small-sized transistor capable of amplifying stably at high frequencies by interconnecting gate electrodes or base electrodes through resistors. CONSTITUTION:One end of a comb-shapedly formed gate electrode 11 is connected to a gate feeding terminal 12 and the other ends of the neighboring gate electrodes 11 are connected through resistance 21 respectively. Source electrodes 13 are arranged to every other gate electrode 11 for being each other connected through an upper layer wiring 14 such as an air bridge. Drain electrodes 15 are arranged to every other gate electrode 11 for being connected to a drain feeding terminal 16 through an upper layer wiring 22 such as an air bridge. Thereby, operation having dispersed absorption of oscillation power and being stable in a high-frequency band can be realized. Moreover, it can be small-sized because oscillation by a structure using no transmitting wire path for power distribution.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency and high output transistor which enables stable amplification in a high frequency band.

[0002]

2. Description of the Related Art Higher transistor output is achieved by increasing the gate width of a field effect transistor (hereinafter referred to as "FET") and the total area of a base electrode of a bipolar transistor, thereby increasing the allowable current of each. Has been realized. In this case, a structure is generally used in which the gate electrode and the base electrode are formed in a comb-teeth shape and power is supplied to each gate electrode and the base electrode of the comb-teeth. The structure of such a high power FET is shown in FIG.

In the figure, reference numeral 11 is a gate electrode formed in a comb tooth shape, and one end thereof is connected to the gate power supply terminal 12. The source electrodes 13 are arranged every other gate electrode 11 and are connected to each other through an upper layer wiring 14 such as an air bridge. The drain electrodes 15 are arranged every other gate electrode 11 and one end thereof is connected to the drain power supply terminal 16.

However, such a structure has a problem that self-oscillation occurs at the time of no input or small signal input when the high frequency amplification capability of the transistor, for example, the mutual conductance is increased to enable high frequency operation. . The cause is considered as follows. When both ends AB of a large number of gate electrodes 11 arranged in a comb tooth shape have a length that cannot be ignored as compared with the wavelength for the amplifiable frequency of the transistor, for example, A and B are reversed. It becomes a phase. At that time, if the non-uniform and random noise generated in the element is locally amplified and is fed back from the drain side to the gate side due to parasitic capacitance, etc.,
It oscillates by satisfying the conditions for stable oscillation.

Therefore, in order to prevent such oscillation,
It is necessary to make the length between AB in FIG. 3 equal to or less than 1/2 of the wavelength with respect to the amplifiable frequency of the transistor, or to devise so as not to satisfy the oscillation condition. The structure of such a high power FET is shown in FIG. This is to enable high output while preventing oscillation by dividing the transistor into two and connecting them in parallel using a power distribution transmission line and a power combining transmission line.

In the figure, 17 is a power distribution transmission line, 18 is a power combining transmission line, and 19 is a resistor for connecting the divided transistors. In this structure, since each of the divided transistors is miniaturized, they do not oscillate independently. Further, a resistor 19 is connected between both transistors to absorb a potential difference (phase difference) between AB and prevent the oscillation from rising. The resistance value of the resistor 19 is made substantially equal to the equivalent resistance value of the transistor when the transistor is viewed from the resistor 19.

[0007]

By the way, in the structure shown in FIG. 4, the length of the power distribution transmission line 17 is 1/2.
At the wavelength, the effect of resistance becomes maximum, and when it is too short, both ends of the resistor 19 are short-circuited and the resistance does not work. That is, this structure is a structure in which the length of the power distribution transmission line 17 is utilized to exert resistance and prevent oscillation. Therefore, the power distribution transmission line 17 needs to have a certain length, which inevitably leads to an increase in the transistor chip size.

It is an object of the present invention to provide a high frequency and high output transistor which enables stable amplification in a high frequency band and is small in size and low in cost.

[0009]

The present invention provides a high-frequency high-power transistor having a plurality of gate electrodes or base electrodes, one end of which is connected to the gate power supply terminal or the base power supply terminal. The other end of the electrode or the base electrode is connected to each other via a resistor.

The other end of the adjacent gate electrode or base electrode is connected through a resistor. Further, the other ends of the plurality of gate electrodes or base electrodes are connected in parallel via a resistor.

[0011]

In the high frequency high output transistor of the present invention, when a potential difference occurs between the gate electrodes, the resistor connected to the other end of each gate electrode acts in such a direction as to absorb the potential difference between the gate electrodes. . That is, in the conventional structure, one resistor absorbs all the oscillation power, but in the structure of the present invention, each resistor disperses and absorbs the oscillation power. Moreover, in the conventional structure, the power distribution transmission line having a predetermined length is indispensable for effectively operating the resistor, but in the structure of the present invention, it is not necessary.

[0012]

EXAMPLE The example shown below is for a FET,
The same applies to a bipolar transistor. In that case, the gate corresponds to the base, the drain corresponds to the collector, and the source corresponds to the emitter.

FIG. 1 shows a first embodiment of the present invention. In the figure, one end of the gate electrode 11 formed in the shape of a comb is connected to the gate power supply terminal 12, and the adjacent gate electrode 1 is connected.
The other end of 1 is connected via a resistor 21. The source electrodes 13 are arranged every other gate electrode 11 and are connected to each other through an upper layer wiring 14 such as an air bridge. The drain electrode 15 is each gate electrode 1
Every other one is arranged with respect to No. 1, and each is connected to the drain power supply terminal 16 via the upper layer wiring 22 such as an air bridge. In addition, as in the conventional structure, the drain electrode 15
The drain power supply terminal 16 may be integrated and the resistor 21 may be connected by an upper layer wiring.

In this structure, when the non-uniform and random noise generated in the element is locally amplified and is fed back from the drain side to the gate side due to parasitic capacitance or the like, on the gate power supply terminal 12 side, between the AB terminals. The low loss causes a high-frequency standing wave to start oscillation. At this time, a potential difference occurs between the adjacent gate electrodes 11, but the resistor 21 connected to the other end of each gate electrode 11 acts in a direction to absorb the potential difference between the adjacent gate electrodes. Therefore, the oscillation can be prevented by setting the resistance value of the resistor 21 under the condition that the feedback coefficient of the positive feedback in which the oscillation is about to rise is set to 1 or less. The absorption of the oscillation power by the resistor 21 becomes maximum when it is equal to the equivalent resistance value of the FET when the FET is viewed from the resistor 21.
Further, when the FET operates normally and no potential difference occurs between the gate electrodes, it is equivalent to the case where the resistor 21 is not connected, and there is no adverse effect due to the connection of the resistor 21.

FIG. 2 shows a second embodiment of the present invention. In the figure, one end of the gate electrode 11 formed in the shape of a comb tooth is connected to the gate power supply terminal 12, and the other end of each gate electrode 11 is connected to one end of a resistor 23.
The other end of 3 is connected via a conductor 24. Source electrode 1
Every other three electrodes 3 are arranged with respect to each gate electrode 11 and are connected to each other through an upper layer wiring 14 such as an air bridge. Every other drain electrode 15 is arranged with respect to each gate electrode 11, and each drain electrode 15 is connected to a drain power supply terminal 16 via an upper layer wiring 22 such as an air bridge. The drain electrode 15 and the drain power supply terminal 16 may be integrated as in the conventional structure, and the conductor 24 may be connected by the upper wiring.

Also in this structure, when a potential difference is generated between the gate electrodes, the principle that the resistor 23 connected to the other end of each gate electrode acts in the direction of absorbing the potential difference between the gate electrodes is as follows. This is the same as in the first embodiment. The feature of the present embodiment is that the resistance value between the gate electrodes can be made uniform. That is, since the resistance value is the same between the adjacent gate electrodes and between the farthest gate electrodes, it is possible to effectively absorb any potential difference between the gate electrodes.

[0017]

As described above, the high frequency high power transistor of the present invention can disperse and absorb the oscillation power and realize stable operation in the high frequency band. Moreover, since the oscillation can be prevented by the structure that does not use the power distribution transmission line, the size can be reduced. Further, it is suitable for a monolithic IC, and a low-cost high-frequency high-power transistor can be obtained.

[Brief description of drawings]

FIG. 1 is a diagram showing a structure of a first embodiment of the present invention.

FIG. 2 is a diagram showing a structure of a second embodiment of the present invention.

FIG. 3 is a diagram showing a structure of a conventional high-power FET.

FIG. 4 is a diagram showing a structure of a conventional high-power FET that is provided with a measure for preventing oscillation for high frequencies.

[Explanation of symbols]

 11 Gate Electrode 12 Gate Feeding Terminal 13 Source Electrodes 14 and 22 Upper Layer Wiring 15 Drain Electrode 16 Drain Feeding Terminal 17 Power Distribution Transmission Line 18 Power Combining Transmission Line 19, 21, 23 Resistor 24 Conductor

Claims (3)

[Claims] 1. A high frequency high output transistor having a structure having a plurality of gate electrodes or base electrodes, one end of which is connected to a gate power supply terminal or a base power supply terminal, wherein the other ends of the plurality of gate electrodes or base electrodes are provided. A high-frequency high-power transistor, characterized in that the two are connected to each other through a resistor. 2. The high frequency high output transistor according to claim 1, wherein the other ends of adjacent gate electrodes or base electrodes are connected to each other through a resistor. 3. The high frequency high output transistor according to claim 1, wherein the other ends of a plurality of gate electrodes or base electrodes are connected in parallel via a resistor. .