JPH05175434A - Semiconductor device - Google Patents

Abstract

PURPOSE:To provide a semiconductor device which can obtain stable Gm. CONSTITUTION:A gate electrode part 10 having a first gate electrode 11 and a second gate electrode 12 is provided. An active region 20, which comprises a drain electrode 13 provided on one side of the gate electrode part 10 and a source electrode 14 provided on the other side, is provided. A protecting diode 15 is electrically connected between a connecting second gate electrode 22, which is provided in the conducting state with the second gate electrode 12, and the source electrode 14. A semiconductor device 1 is formed in this way. The protecting diode 15 is arranged in such a state wherein the direction of electric lines of force 30 generated around the protecting diode 15 is not directed at least toward the side of the active region 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device having a dual gate field effect transistor provided with a protection diode.

[0002]

2. Description of the Related Art A dual gate field effect transistor (hereinafter referred to as FET) having two gate electrodes, a first gate electrode and a second gate electrode, is mainly used as an amplifier for a high frequency of a television tuner or the like. , A transistor that has the advantages of low noise and low cross-modulation. A semiconductor device including this dual gate FET will be described with reference to the schematic diagram of the electrode layout in FIG. That is, the electrode layout of the semiconductor device 1 is shown, and the gate electrode portion 1 having the first gate electrode 11 and the second gate electrode 12 is shown.
0, a drain electrode 13 provided on one side of the gate electrode section 10, and a source electrode 14 provided on the other side. The gate electrode section 10, the drain electrode 13 and the source electrode 14 make it active. The area 20 is configured. A second gate electrode 22 for connection, which is in conduction with the second gate electrode 12, is provided in the vicinity of the source electrode 14 in the active region 20, and between the second gate electrode 22 for connection and the source electrode 14. Protection diode 15
Are connected.

The protection diode 15 is composed of an n-type semiconductor and a p-type semiconductor.
When a large current is about to flow into the dual gate FET of the semiconductor device 1, the protection diode 15 prevents the gate electrode portion 10 from being damaged.

[0004]

However, this semiconductor device has the following problems. That is, FIG.
As shown in, in the vicinity of the protection diode 15 connected between the connection second gate electrode 22 and the source electrode 14,
The lines of electric force 30 are generated from the side of the connection second gate electrode 22 having a high potential toward the side of the source electrode 14 having a low potential. Therefore, the lines of electric force 3 generated in this direction
0 adversely affects the channel region below the gate electrode portion 10 in the active region 20, and periodically changes the ratio of the change of the drain current with respect to the change of the first gate voltage, that is, the transconductance (hereinafter, referred to as Gm). I will let you. Due to this periodic change in Gm, the characteristics of the semiconductor device 1 become unstable, and it becomes difficult to obtain a desired amplification effect. Therefore, the present invention provides stable G
It is an object of the present invention to provide a semiconductor device in which m is obtained.

[0005]

The present invention is a semiconductor device made to solve the above problems. That is, a drain electrode is provided on one side of a gate electrode portion having a first gate electrode and a second gate electrode, and a source electrode is provided on the other side, and a source electrode side of this active region. In a semiconductor device having a second gate electrode for connection provided in the vicinity of the second gate electrode in a conductive state and a protection diode connected between the second gate electrode for connection and the source electrode. This protection diode is connected in a state in which the direction of the lines of electric force generated around the diode does not at least face the active region side.

[0006]

Since the protection diode is connected between the source electrode and the side of the connection second gate electrode other than the side on the active region side, the direction of the lines of electric force generated around the protection diode is At least not towards the active area. Therefore, the electric charges that form the lines of electric force generated around the protection diode do not enter the gate electrode portion, and do not adversely affect the channel region.

[0007]

Embodiments of the semiconductor device of the present invention will be described below with reference to the drawings. 1A and 1B are diagrams illustrating a semiconductor device of the present invention. FIG. 1A is a schematic diagram of an electrode layout, and FIG. 1B is a circuit diagram. That is, the semiconductor device 1 of the present invention has the first gate electrode 11 and the second gate electrode 1 in the gate electrode portion 10.
2 has two gate electrodes, and the active region 20 composed of the drain electrode 13 provided on one side of the gate electrode portion 10 and the source electrode 14 provided on the other side constitutes a dual gate FET. It was done.

In the vicinity of the source electrode 14 in the active region 20, a second gate electrode 22 for connection, which is in conduction with the second gate electrode 12 (see FIG. 1B), is provided. The second connection gate electrode 22 has a substantially parallel side 22a of the active region 20 near the source electrode 14, a substantially parallel side 22b of the far side, and a substantially vertical side 22c connecting these. Further, the source electrode 14 is formed near the side of the connection second gate electrode 22 opposite to the active region 20.
Is provided, and the protection diode 15 is connected between the source electrode 14 and the side 22b of the connection second gate electrode 22. When the positive bias is applied to the second gate electrode 12, the electric line of force 30 generated around the protection diode 15 arranged in this way is supplied with a potential from the side of the connection second gate electrode 22 having a high potential. It is generated toward the low source electrode 14 side. Therefore, the lines of electric force 30 do not at least go to the active region 20. As a result, the electric charges that form the lines of electric force 30 do not enter the gate electrode portion 10, and do not adversely affect the channel region.

Next, another embodiment of the semiconductor device of the present invention will be described with reference to the drawings. FIG. 2 is a schematic diagram of an electrode layout of another embodiment of the present invention. That is, the source electrode 14 of the active region 20 is the second gate electrode 22 for connection.
The protection diode 15 is connected between the source electrode 14 and the side 22c of the connecting second gate electrode 22. Lines of electric force 30 generated around the protection diode 15 connected in this way
Is the gate electrode portion 10 disposed in the active region 20.
Head in a direction substantially parallel to. Therefore, as compared with the electrode layout in which the lines of electric force 30 are directed toward the active region 20 as shown in FIG. 3, the electrode layout has less adverse effect on the channel region below the gate electrode portion 10. However, due to the spread of the lines of electric force 30, some electric charges are directed toward the active region 20, so that the electrode layout is more likely to have a bad influence on the channel region than the electrode layout shown in FIG. Therefore, when the dual gate FET is used with a low second gate voltage, the electric flux lines 30 do not adversely affect the channel region. Note that this electrode layout is effective in reducing the size of the semiconductor device 1 because the area of the electrodes can be made smaller than that of the electrode layout of FIG.

In any of the embodiments, the protection diode 15 is connected so that the lines of electric force 30 generated around the protection diode 15 are not oriented at least in the direction of the active region 20, so that the gate electrode portion 10 is connected. It is possible to reduce the invasion of electric charges into the channel region below. Although the case where the pnp type protection diode 15 is used has been described in the above embodiment, the present invention may use the npn type protection diode 15.

[0011]

As described above, the semiconductor device of the present invention has the following effects. That is, since it is possible to reduce the intrusion of charges generated around the protection diode, which adversely affects the channel region below the gate electrode portion, it is possible to prevent a periodic change in Gm. Therefore, a semiconductor device having stable Gm can be provided, and a highly reliable product can be provided.

[Brief description of drawings]

1A and 1B are diagrams illustrating a semiconductor device of the present invention, in which FIG. 1A is a schematic diagram of an electrode layout, and FIG. 1B is a circuit diagram.

FIG. 2 is a schematic diagram illustrating an electrode layout according to another embodiment of the present invention.

FIG. 3 is a schematic diagram illustrating an electrode layout of a conventional semiconductor device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Semiconductor device 10 Gate electrode part 11 1st gate electrode 12 2nd gate electrode 13 Drain electrode 14 Source electrode 15 Protection diode 20 Active area 22 Second gate electrode for connection 30 Electric force line

Claims (1)

[Claims] 1. A drain electrode is provided on one side of a gate electrode portion having a first gate electrode and a second gate electrode,
And an active region having a source electrode on the other side, and a second connecting region provided in a conductive state with the second gate electrode in the vicinity of the source electrode side of the active region.
In a semiconductor device having a gate electrode and a protection diode connected between the connection second gate electrode and the source electrode, a direction of a line of electric force generated around the protection diode is at least the active region. A semiconductor device, wherein the protection diode is connected so as not to face to the side.