JPH0494137A - Field effect transistor - Google Patents

Abstract

PURPOSE:To take it out without crossing a source electrode by including a gate electrode, which forms a Schottky junction with a compound semiconductor layer and has specified zigzag plane structure with a specified width, and a source electrode and a drain electrode, which are provided severally specified intervals apart from the gate electrode. CONSTITUTION:At the substrate 1 consisting of a semiinsulating GaAs semiconductor is made an active layer, and on the same layer is provided a gate electrode 2, which forms a Schottky junction. The gate electrode 2 is composed of six parallel electrode fingers 2a and five electrode finger 2b, which connect the tips of the electrode fingers 2a alternately. A source electrode 3 and a drain electrode 4 are provided to severally keep specified intervals from the gate electrode 2. The source electrodes 3 and the drain electrodes 4 are alternately provided between the electrode fingers 2a of the gate electrode. Accordingly, the power supply to the gate electrode 2 can be done without crossing the source electrode 3.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industry - Second Field of Application) The present invention relates to the structure of a power field effect transistor, particularly to the planar structure of a gate electrode.

[Prior art] Shot on compound semiconductors such as GaAs!・A field effect transistor with a gate that forms a key junction (
FETs (hereinafter referred to as FETs) can be used at high frequencies such as microwave bands, and can perform amplification with low noise and high power efficiency.

In order to increase the output power of such FET,
The gate width (ie, the length of the gate feed perpendicular to the direction of source-drain current flow) needs to be increased. Therefore, conventionally, a gate electrode structure called a comb structure as shown in FIG. 2 has been used. This structure is based on a semiconductor substrate l containing predetermined impurities.
At the top, a plurality of linear gate electrode fingers 2f
are connected to the gate power supply section 2g at one end of each.

Source electrodes 3 and drain electrodes 4 are alternately provided between the gate electrode fingers 2f.

In this way, by dividing the Goo-l-electrode into a plurality of Goo-l-electrode fingers 2f, the dimensions of the semiconductor substrate 1 can be made easy to handle, damage during the manufacturing process can be prevented, and 1.
High frequency characteristics in the microwave band are improved by reducing stray capacitance.

[Problems to be Solved by the Invention] However, manufacturing an FET having such a gate electrode with a comb-shaped structure requires complicated steps. That is, since the source electrode 3 and the gate power supply section 2g intersect,
A two-layer wiring 5 is required in this part. Since an increase in the capacitance between the gate and source electrodes causes deterioration of the high frequency characteristics of the FET, an aerial wiring called an air bridge is used for the two-layer wiring 5. This complicates the manufacture of the FET and causes an increase in cost.

The purpose of the present invention is to eliminate the need for such complicated steps,
The object of the present invention is to provide a power FET structure that can be fabricated on a semiconductor substrate of desired dimensions.

[Means and effects for solving the problems 1] A field effect transistor according to the present invention has a compound semiconductor layer, a Schottky junction formed with the compound semiconductor layer, and a zigzag or meandering curved planar structure with a predetermined width. The device is characterized in that it includes a gate electrode, and a drain electrode and a source electrode that are respectively provided at a predetermined interval from the gate electrode and form an ohmic contact with the compound semiconductor layer.

According to the present invention, since the gate electrode has a zigzag shape or a meandering curve shape with no branches except for the power supply part to the gate electrode, it can be taken out without crossing the source electrode (or drain electrode). .

(Example] Hereinafter, the present invention will be explained in detail with reference to Examples.

FIG. 1 shows a plan view of the main parts of the GaAsFET, which is one embodiment.

An active layer is formed on a substrate 1 made of a semi-insulating GaAs semiconductor by a known method such as epitaxial growth. A gate electrode 2 with a width of 1 μm (gate length: 1 μm) forming a Schottky junction is provided on this active layer. The gate electrode 2 has six parallel lines with a length of 150μ.
It is composed of m electrode fingers 28 and five 100 μm long electrode fingers 2b which alternately connect the ends of the electrode fingers 2a, and the gate width is 1400 μm.

The source electrode 3 and the drain electrode 4 are provided at intervals of 1.5 μm and 2.0 μm from the gate electrode 2, respectively. Source electrodes 3 and drain electrodes 4 are alternately provided between the electrode fingers 2a of the gate electrodes. Therefore, power can be supplied to the gate electrode 2 without crossing the source electrode 3.

As another embodiment, the gate electrode 2 can have a meandering curved shape. Assuming an X-Y coordinate perpendicular to the substrate l, such a curve is Y=As i n
Represented by the trigonometric function of (B - X) (A and B are constants)
Shapes can be used.

When using a gate electrode with a shape in which straight electrode fingers are connected, at the connection part of orthogonal electrode fingers,
The distances between the gate electrode and the source and drain electrodes are non-uniform compared to other gate electrode portions. However, by forming the gate electrode 2 in a meandering curved shape, such unevenness in distance can be prevented, and all parts of the formed gate electrode 2 can be used effectively, improving the performance of the FET. I can do it.

(Effect of the Invention 1 As explained above, the field effect transistor according to the present invention has a compound semiconductor layer, a Schottky junction with the compound semiconductor layer, and a zigzag or meandering curved planar structure with a predetermined width. The device is characterized in that it includes a gate electrode, and a drain electrode and a source electrode that are respectively provided at a predetermined interval from the gate electrode and form an ohmic contact with the compound semiconductor layer.

According to the present invention, since the gate electrode has a zigzag shape or a meandering curve shape with no branches except for the power supply portion to the gate electrode, the source electrode (or drain electrode)
You can take it out without having to cross it.

Therefore, it is possible to fabricate on a semiconductor substrate of desired dimensions without requiring complicated processes such as two-layer wiring.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an FET for explaining the present invention in detail, and FIG. 2 is a plan view of an FET for explaining the prior art. In the figure,

Claims (1)

[Scope of Claims] A compound semiconductor layer; a gate electrode forming a Schottky junction with the compound semiconductor layer and having a zigzag or meandering curved planar structure with a predetermined width; and a gate electrode separated from the gate electrode by a predetermined distance, respectively. A field effect transistor comprising: a drain electrode and a source electrode, which are provided in the compound semiconductor layer and form an ohmic contact with the compound semiconductor layer.