JPH10242387A - Microwave integrated circuit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To attain a low resistance while limiting the area by arranging ohmic electrodes alternately and oppositely on the conductive region of a semiconductor thereby constituting a pair of ohmic electrodes. SOLUTION: A conductive region 102 is formed by implanting ions selectively into a semiinsulating GaAs substrate, for example, and first and second ohmic electrodes 101a, 101b are arranged thereon interdigitally at regular intervals while facing each other thus constituting a pair of ohmic electrodes. Since a pair of ohmic electrodes are arranged interdigitally while facing each other in a resistor, the length B of facing side is equal to the product Axn, i.e., the length A multiplied by the number of pairs n of electrode (4 pairs) facing interdigitally. For example, a resistance of 5Ωcan be attained with an area of 1,000μm<2> for 4 pairs of electrode and the area can be decreased or a lower resistance can be attained for the same area.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a microwave integrated circuit formed on a semi-insulating semiconductor substrate such as GaAs.

[0002]

2. Description of the Related Art In recent years, microwave solid-state circuits have become smaller,
GaAs is used for matching circuits and semiconductors such as FETs to reduce costs.
A monolithic microwave integrated circuit (hereinafter, MMIC) integrated on a semi-insulating semiconductor substrate such as s is widely used.

FIG. 4 is an equivalent circuit showing an example of an amplifier using a GaAs FET. In the figure, 401 is Ga
As FETs, 402 to 405 are transmission circuits forming a matching circuit, 406 and 407 are DC blocking capacitors, 41
0 is a stabilizing resistor.

A resistor denoted by reference numeral 410 in FIG. 2 is connected in series to a gate electrode of the FET, and is used for an MMIC.
It has the function of absorbing the characteristic variation of 401 and suppressing the operation such as the parasitic oscillation of the FET. Usually, the resistance value is selected in proportion to the input impedance on the gate side of the connected FET, for example, in inverse proportion to the gate width.

In order to realize the above resistor, there are a method using a high-resistance metal thin film, a method using a semiconductor conductive region and a pair of ohmic electrodes, and the like.
In many cases, a configuration using a conductive region and a pair of ohmic electrodes is adopted because of good compatibility with the T process.

FIG. 5 shows a conventional example of a resistor having a configuration using a conductive region and a pair of ohmic electrodes. In the figure, 501a and 501b are, for example, AuGe / Ni
Are ohmic electrodes, and are opposed to each other at a predetermined interval to form a pair of ohmic electrodes. Reference numeral 502 in the figure denotes a conductive region selectively formed on a semi-insulating semiconductor substrate. This conductive region is formed, for example, by selectively implanting Si ions into a semi-insulating GaAs substrate.

In order to obtain a desired resistance value by the resistor having such a structure, the sheet resistivity of the conductive region of the semiconductor is changed or the interval between the ohmic electrodes forming a pair (the length of the resistor) is changed. Alternatively, it can be realized by changing the length (B in the figure, width of the resistor) overlapping the conductive region on the opposite side of the ohmic electrode.

[0008]

In recent years, as the output of the MMIC has been increased, the gate width of the FET has been increased.
The input and output impedances of the FET are low. Correspondingly, the resistance value required for a resistor of a matching circuit such as a stabilizing resistor is also low. For example, for an FET having a gate width of 10 mm, a value of about 5 to 6Ω is generally used. Required.

In order to realize a low resistance value with the above-described conventional resistor, the surface resistivity of the conductive region is reduced by increasing the impurity concentration, the electrode interval between the ohmic electrodes is reduced, and the resistance is reduced. By making the side to be long, a low resistance value can be realized. However, if the distance between the electrodes is too small, the yield may be reduced due to a short circuit, or a high electric field may be generated when a voltage is applied. For this reason, it is often the case that the interval is not narrower than about several microns.

Further, the sheet resistivity of the conductive region does not decrease even if the impurity concentration is increased by a certain amount or more. For this reason, when a lower resistance value is required, the resistance value is reduced by increasing the length B of the opposite side of the ohmic electrode. For this reason, high output M which requires a low resistance value
In an MIC or the like, not only the FET becomes large due to the high output, but also the resistor as a matching element becomes large, resulting in an MMIC having a very large element area. For this reason, the degree of integration is not increased, which causes a decrease in yield and an increase in MMIC unit price.

The present invention solves the above-mentioned drawbacks, and provides a microwave integrated circuit provided with a resistor having a structure which can realize a low resistance value in a small area by using a resistor composed of an active region and a pair of ohmic electrodes. The purpose is to provide.

[0012]

SUMMARY OF THE INVENTION To solve the above problems, the present invention relates to a microwave integrated circuit having a semiconductor conductive region and a pair of ohmic electrodes arranged in a desired region on a semi-insulating semiconductor substrate. The present invention is characterized in that ohmic electrodes are alternately arranged on a conductive region of a semiconductor so as to face each other to form a pair of ohmic electrodes.

In a microwave integrated circuit in which a semiconductor conductive region and a pair of ohmic electrodes are disposed in a desired region on a semi-insulating semiconductor substrate, a comb-shaped pair of comb-shaped electrodes is provided on the semiconductor conductive region. An ohmic electrode is formed.

In a microwave integrated circuit in which a semiconductor conductive region and a pair of ohmic electrodes are arranged in a desired region on a semi-insulating semiconductor substrate, a pair of spiral ohms is formed on the semiconductor conductive region. And a conductive electrode.

In a microwave integrated circuit having a field effect transistor disposed on a semi-insulating semiconductor substrate and a semiconductor conductive region and a pair of ohmic electrodes disposed in a desired region on the semi-insulating semiconductor substrate. The present invention is characterized in that ohmic electrodes are alternately arranged on a conductive region of a semiconductor so as to face each other to form a pair of ohmic electrodes.

In a microwave integrated circuit, a field effect transistor is arranged on a semi-insulating semiconductor substrate, and a semiconductor conductive region and a pair of ohmic electrodes are arranged in a desired region on the semi-insulating semiconductor substrate. A pair of comb-shaped ohmic electrodes are formed on a conductive region of a semiconductor.

Further, in a microwave integrated circuit in which a field effect transistor is arranged on a semi-insulating semiconductor substrate, and a semiconductor conductive region and a pair of ohmic electrodes are arranged in a desired region on the semi-insulating semiconductor substrate. A pair of spiral ohmic electrodes is formed on a conductive region of a semiconductor.

Further, a semiconductor conductive region formed by selective ion implantation on the semi-insulating semiconductor substrate is used.

Further, the same pattern as the source electrode and the drain electrode of the field effect transistor is used as the pair of ohmic electrodes.

The pair of ohmic electrodes is made of AuGe / N
i.

A pair of ohmic electrodes is made of AuGe / P
t.

The microwave integrated circuit according to the present invention comprises a pair of electrodes in which ohmic electrodes are alternately arranged to face each other, and has, for example, a comb-shaped or spiral structure. For this reason, the opposing electrode length can be increased with the same area as the conventional one,
Low resistance can be achieved in a small area.

[0023]

FIG. 1 is a plan view showing an embodiment of the present invention. In FIG. 1, reference numerals 101a and 101b denote a first ohmic electrode and a second ohmic electrode using, for example, AuGe / Ni, which are opposed to each other in a comb shape at a predetermined interval to form a pair of ohmic electrodes. doing. Reference numeral 102 in the drawing denotes a conductive region selectively formed on the semi-insulating semiconductor substrate. This conductive region is formed, for example, by selectively implanting Si ions into a semi-insulating GaAs substrate.

A pair of ohmic electrodes 101a and 101b
Can be formed using the pattern of the source electrode and the drain electrode of the FET. Therefore, a resistor having a low resistance value can be realized with a small area without increasing the number of manufacturing steps.

As shown in the figure, in the resistor according to the present invention, a pair of ohmic electrodes face each other in a comb shape. For this reason, the length corresponding to the length B of the opposite side in the conventional example is obtained by multiplying the length A by the number n (four pairs in the example in the figure) of the pair of electrodes facing each other in a comb shape. The length is A × n. Thus, for example, in order to achieve a resistance of 5 [Omega, but the area where about 3500 ² in the conventional example was needed, next 1000 .mu.m ² when the four pairs of opposite number, according to the present invention, in the area About 70% reduction is possible. Therefore, a lower resistance value can be realized in the same area as in the conventional example.

FIG. 2 shows another embodiment of the present invention.
Shown in In this case, the electrodes at both ends of the comb-shaped ohmic electrode are longer than those in the example of FIG. 1, and the conductive regions are formed in all of the comb-shaped gaps. Therefore, the opposing length can be made longer than A × n in the case of FIG. 1, and a lower resistance can be realized in the same area.

In the present invention, the FET is formed on the same semi-insulating semiconductor substrate, but is omitted in the description. FETs not described often constitute opposing comb-shaped electrodes, and a pair of ohmic electrodes 101a and 101b are FE-shaped.
It can be formed using the pattern of the source electrode and the drain electrode of T. Therefore, a low-resistance resistor can be realized in a small area without increasing the number of manufacturing steps.

FIG. 3 shows another embodiment of the present invention. In the above description, the case where the pair of ohmic electrodes is comb-shaped has been described.

Thus, according to the present invention, with the same area,
Since a resistance value lower than that of the related art can be realized, a resistor with a higher degree of integration can be provided. Therefore, a microwave integrated circuit having the same function can be realized on a small semiconductor substrate, and the manufacturing cost can be reduced.

In the above embodiment, AuGe / Ni is exemplified as the ohmic electrode. However, it is clear from the above description that AuGe / Pt may be used, and that the semi-insulating substrate may be InP instead of GaAs. The method for forming the conductive region is not limited to the ion implantation method, and the present invention can be implemented.

It is clear from the above description that the number of branched electrode branches, the length of the electrode branches, and the shape of the conductive region are not limited to those shown in FIGS. Further, the shape of the spiral is not limited to the shape shown in FIG.

[0032]

According to the present invention, since a low resistance value can be realized in the same area, a resistor with higher integration and a microwave semiconductor with higher integration can be provided.

[Brief description of the drawings]

FIG. 1 is a plan view illustrating the present invention.

FIG. 2 is a plan view illustrating the present invention.

FIG. 3 is a plan view illustrating the present invention.

FIG. 4 is an equivalent circuit diagram of a conventional amplifier using an FET.

FIG. 5 is a plan view illustrating a conventional example.

[Explanation of symbols]

 101a first ohmic electrode 101b second ohmic electrode 102 conductive region A length A 201a first ohmic electrode 201b second ohmic electrode 202 conductive region 301a first One ohmic electrode 301b Second ohmic electrode 302 Conductive region 401 GaAs FETs 402 to 405 Transmission lines 406 and 407 DC blocking capacitors 408 and 409 High frequency short circuit capacitor 410 Stabilizing resistor 501a ... First ohmic electrode 501b ... Second ohmic electrode 502 ... Conductive area B ... Length B

Claims (10)

[Claims] 1. A method according to claim 1, wherein a desired region on the semi-insulating semiconductor substrate is
In a microwave integrated circuit in which a conductive region of a semiconductor and a pair of ohmic electrodes are arranged, a pair of ohmic electrodes are formed by alternately opposing ohmic electrodes on the conductive region of the semiconductor. Microwave integrated circuit. 2. In a desired region on a semi-insulating semiconductor substrate,
A microwave integrated circuit in which a semiconductor conductive region and a pair of ohmic electrodes are arranged, wherein a pair of comb-shaped ohmic electrodes are formed on the semiconductor conductive region. 3. In a desired region on a semi-insulating semiconductor substrate,
A microwave integrated circuit in which a semiconductor conductive region and a pair of ohmic electrodes are arranged, wherein a pair of spiral ohmic electrodes are formed on the semiconductor conductive region. 4. A microwave integrated circuit in which a field effect transistor is disposed on a semi-insulating semiconductor substrate, and a semiconductor conductive region and a pair of ohmic electrodes are disposed in a desired region on the semi-insulating semiconductor substrate. A microwave integrated circuit, wherein ohmic electrodes are alternately arranged on a conductive region of a semiconductor to form a pair of ohmic electrodes. 5. A microwave integrated circuit in which a field effect transistor is disposed on a semi-insulating semiconductor substrate, and a semiconductor conductive region and a pair of ohmic electrodes are disposed in a desired region on the semi-insulating semiconductor substrate. A microwave integrated circuit comprising a pair of comb-shaped ohmic electrodes formed on a conductive region of a semiconductor. 6. A microwave integrated circuit in which a field effect transistor is disposed on a semi-insulating semiconductor substrate, and a semiconductor conductive region and a pair of ohmic electrodes are disposed in a desired region on the semi-insulating semiconductor substrate. A microwave integrated circuit, comprising a pair of spiral ohmic electrodes formed on a conductive region of a semiconductor. 7. The microwave integrated circuit according to claim 1, wherein a semiconductor conductive region formed on said semi-insulating semiconductor substrate by selective ion implantation is used. 8. The microwave integrated circuit according to claim 4, wherein the same pattern as the source electrode and the drain electrode of the field effect transistor is used as the pair of ohmic electrodes. 9. The microwave integrated circuit according to claim 1, wherein the pair of ohmic electrodes is made of AuGe / Ni. 10. A pair of ohmic electrodes are made of AuGe / Pt.
7. The microwave integrated circuit according to claim 1, comprising: