JPH07111271A - High power field-effect transistor - Google Patents

Abstract

PURPOSE:To suppress an oscillation caused by the signal fed back between the unit field-effect transistors connected in parallel with each other in order to obtain a high output power. CONSTITUTION:A high power transistor module is composed of a number of unit field-effect transistors. A plurality of unit gate electrodes 3 or a plurality of unit drain electrodes 5 are connected to each other with bus-bar electrode 2 or 8 so as to form a comb shape to constitute a unit cell 9. The respective bus-bar electrodes of the same electrodes of both unit cells adjacent to each other are connected to each other with a resistance element 4 composed of an ohmic resistor 4a or a thin film metal resistor 4b. With this constitution, the integrated gain of a loop produced by the fed-back signals between the unit transistors 3a and 3b can be reduced and an unnecessary oscillation can be suppressed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a field effect transistor having a plurality of unit gate electrodes and unit drain electrodes arranged in a comb shape, and more particularly to a field effect transistor capable of obtaining a high output in a high frequency band higher than a microwave band.

[0002]

2. Description of the Related Art As shown in FIG. 2, a conventional field effect transistor has a first bus bar electrode (12) in which a plurality of unit gate electrodes (3) are arranged in a comb shape, and a first electrode connected to a bonding electrode (7). The two bus bar electrodes (16) are laminated via the insulating film (14), and the insulating film (1
Both are electrically connected to each other through a through hole (15) provided in 4). And this through hole (1
5) is arranged at a position where the geometrical distances between the unit gate electrodes (3) and the bonding electrodes (7) are equal to each other (for example, JP-A-3-58435). With this configuration, the distance between each unit gate electrode (3) and the bonding electrode (7) becomes equal. Therefore,
The phase difference between the unit gate electrodes (3) is minimized with respect to the frequency signal using the bonding electrode (7) as a feeding point, and the phase difference for a high frequency signal such as a microwave band is mitigated. It is possible to eliminate the non-uniform operation in.

[0003]

The field effect transistor described above alleviates the phase difference passing through each unit transistor. However, if the performance of the unit transistors is improved to operate at a very high frequency, the gain becomes 1 at the frequency where the electrical delay time between the unit transistors becomes a half cycle.
In the above case, oscillation may occur. For example, there is a physical distance between the leftmost unit transistor (3a) and the rightmost unit transistor (3b) in FIG.
This distance causes a delay time, and the unit transistor (3a) →
Bus bar electrode (8) → unit transistor (3b) → first
In the loop (arrow in the figure) of the bus bar (12) → unit transistor (3b), the phase becomes 2nπ, n becomes 1, 2, 3, ... And oscillation occurs when the total gain becomes 1 or more. The higher the operating frequency of the unit transistor, the more easily the small loop oscillates, and the high-output field-effect transistor in which a large number of unit transistors operate in parallel has a problem that the above-mentioned possibility of oscillation increases.

[0004]

A high output electric field transistor of the present invention includes a unit cell in which a plurality of unit gate electrodes or unit drain electrodes are connected in a comb shape by bus bar electrodes, and an adjacent unit cell having the same configuration. The bus bar electrodes of both the same electrodes are electrically connected by a resistor.

[0005]

According to the present invention, a unit cell in which a plurality of unit gate electrodes or unit drain electrodes are connected in a comb shape by bus bar electrodes and an intermediate bus bar electrode between the same electrodes of adjacent unit cells having the same structure are provided. By disposing a resistive conductor in, the resistor absorbs unbalance against high frequencies on the same chip (unit transistor), and attenuates the sneak of high frequency signals in the same chip.
Oscillation due to wraparound in the same chip is eliminated.

[0006]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 shows an embodiment of the present invention. (A) is a plan view, (b) and (c) are sectional views taken along the line BB of (a).
A plurality of unit gate electrodes (3), unit drain electrodes (5) and unit source electrodes (6) are formed on a semiconductor substrate (1), and the unit drain electrodes (5) are connected in a comb shape by a bus bar electrode (8). ing. The unit gate electrodes are connected in a comb shape by the bus bar electrodes (2) to form a unit cell (9) which is a group of unit transistors. The bus bar electrodes (2) of adjacent unit cells (9) are electrically connected by a resistor (4). The resistor (4) is formed of an ohmic resistor (4a) using a semiconductor substrate or a resistor (4b) of thin film metal or the like.

According to this structure, the unit transistor (3
a) → bus bar electrode (8) → unit transistor (3b)
→ bus bar electrode (2) → resistor (4) → bus bar electrode (2) → unit transistor (3a) loop, the total gain is reduced by the resistor (4), the total gain of the loop shown in the conventional example The total gain of the present invention is lower than that. Therefore, it becomes possible to suppress oscillation due to the loop. A loop in the unit cell (9) that does not pass through the resistor (4) is also conceivable, but a phase condition for oscillating by configuring the loop length in the unit cell (9) to be short (minimum loop phase is 2π It is possible to increase the frequency at which It is sufficient that the gain is 1 or less at that frequency. If the unit cell (9) is halved in size, the oscillation frequency will be doubled.

Therefore, the oscillation can be suppressed by making the loop phase of the unit cell (9) shorter than the cycle of the maximum oscillation frequency of the unit transistor. In the above description, the resistor (4) is provided on the bus bar electrode of the gate, but the same effect can be obtained by providing it on the bus bar electrode of the drain. Further, if a resistor is provided on each of the drain and gate bus bar electrodes, the effect is further enhanced. Furthermore, the effect is enhanced when the unit cell (9) is divided into smaller parts.

[0009]

As described above, according to the present invention,
By electrically connecting a unit cell in which a plurality of unit gate electrodes or unit drain electrodes are connected to each other in a comb shape by bus bar electrodes and a bus bar electrode of the same electrode on the opposite sides of adjacent unit cells that are similarly configured by a resistor. The total gain of the loop due to the sneak between the unit transistors can be lowered, and there is an effect that unnecessary oscillation can be suppressed.

[Brief description of drawings]

FIG. 1 is a plan view of an embodiment of the present invention, and FIG.
(C) is BB sectional drawing of (a).

2A is a plan view of the related art, and FIG. 2B is a sectional view taken along line AA of FIG.

[Explanation of symbols]

 1 Semiconductor Substrate 2,8 Bus Bar Electrode 3 Unit Gate Electrode 4,4a, 4b Resistor 5 Unit Drain Electrode 6 Unit Source Electrode 3a, 3b Unit Transistor 7 Bonding Electrode 9 Unit Cell 12 First Bus Bar Electrode 14 Insulating Film 15 Through Hole 16 Second bus bar electrode

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[Procedure amendment]

[Submission date] March 29, 1994

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[Name of item to be amended] Claims

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[Claims]

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[Correction target item name] 0004

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[0004]

A high output electric field transistor of the present invention includes a unit cell in which a plurality of unit gate electrodes or unit drain electrodes are connected in a comb shape by bus bar electrodes, and an adjacent unit cell having the same configuration. It is provided with electrically connecting the busbar electrodes of both the same electrodes with a resistor, and also has the same configuration as a unit cell in which a plurality of unit gate electrodes are connected in a comb shape by busbar electrodes. The bus bar electrodes of the same electrodes on the opposite sides of the adjacent unit cells are electrically connected with a low antibody, and the bus bar electrodes with the unit drain electrodes connected in a comb shape are electrically connected with a resistor. It is what

Claims (1)

[Claims] 1. A unit cell in which a plurality of unit gate electrodes or unit drain electrodes are comb-shaped connected to each other by bus bar electrodes,
A high output field effect transistor, characterized in that bus bar electrodes of the same electrodes on opposite sides of adjacent unit cells having the same structure are electrically connected by a resistor.