JPS6388908A - Monolithic integrated circuit - Google Patents

Abstract

PURPOSE:To reduce the forming process and to prevent deterioration in the dielectric strength by forming a branch circuit having three terminals on one and the same plane and having a capacitance between two terminals. CONSTITUTION:A gate input line of a field effect transistor (TR) consists of an input terminal 1b, a metallic line 2b, a terminal 3b connected to an equivalent gate-source capacitance at the gate side of the field effect TR, a metallic line 5b, an output terminal 6b and a gap 7b making the metallic line part between the input terminal 1b and the output terminal 6b adjacent to each other. In propagating a high frequency wave, the gap 7b acts like a capacitance and the line parts 2b, 5b act like inductance, then the full band pass circuit is constituted by selecting the components.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a monolithic integrated circuit, and particularly to a monolithic integrated circuit using a branch circuit having three terminals, two of which have capacitive coupling. It is related to.

[Conventional technology]

Figure 2 shows, for example, 1986 1EEE MTT-S Microwave Symposium Digest 13-17.
Page (Microeyave Symp, Dig, P
, 13-17), and FIG. 3 is a pattern diagram thereof. Distributed monolithic amplifiers utilize the gate-source capacitance and drain-source capacitance of field effect transistors, and connect the gate and drain sides with lumped inductance or distributed constant lines, creating a pseudo distributed constant line. In this way, a broadband amplifier can be obtained.

In the equivalent circuit of FIG. 2, a signal input from the input terminal l has an inductance of 2° due to the metal line and an isometric gate-source capacitance of the field effect transistor connected to the terminal 3, 4. Inductance due to metal line5. The signal is amplified by a bridging T-shaped circuit composed of a capacitor 7 connecting the input terminal 1 and the output terminal 6. It has been found that this circuit becomes an all-pass circuit in which the amplitude of the signal transmitted to the output terminal 6 is constant regardless of the frequency, depending on how the values of the above-mentioned components are selected. Therefore, an extremely wideband amplifier can be constructed.

FIG. 3 is a metal wiring diagram that realizes the equivalent circuit of FIG. 2, and the subscript numbers correspond to the parts constituting each element in FIG. 2. 7a, the output terminal 6a and the input terminal 1a are capacitively coupled by using a parallel plate capacitor in which a dielectric 8 is inserted between the lower metal line 2a and the upper metal line 5a.

[Problem that the invention seeks to solve]

Since the conventional monolithic integrated circuit is configured as described above, the surface roughness of the substrate in the parallel plate volume M1a,
Due to the presence of pinholes during the etching process, the dielectric strength deteriorated, causing reliability problems.

The present invention has been made to solve the above-mentioned problems, and aims to provide a monolithic S product circuit that can simultaneously configure a capacitor when forming a metal line and also prevent deterioration of dielectric strength.

[Means for solving problems]

A monolithic integrated circuit according to the present invention has three terminals on the same plane on a part of the surface of a semi-insulating semiconductor substrate, and a branch circuit is formed so as to have capacitive coupling between two of the terminals,
This is used as a monolithic amplifier, with the two terminals used as input and output terminals, respectively, and the third terminal used as a gate connection terminal.

[Effect]

In the present invention, by using a branch circuit having three terminals on the same plane and having capacitive coupling between two terminals as a monolithic amplifier, a capacitor can be configured at the same time as a strip line, and the dielectric breakdown voltage may deteriorate. can also be prevented.

〔Example〕

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a metal wiring pattern diagram showing one embodiment of the present invention. This equivalent circuit is the same as that in FIG. 2, and the attached numbers in FIG. 1 correspond to each equivalent circuit component.

Moreover, 7b is a gap capacitance constructed by making the metal line of the input terminal 1b and the metal line of the output terminal 6b adjacent to each other.

As shown in the figure, one of the distributed monolithic amplifiers formed on the same plane of the semi-insulating semiconductor substrate according to this embodiment.
The gate input line of the field effect transistor of the cell is an input terminal 1b and a metal line 2b.

It consists of a terminal 3b connected to the isometric gate-source capacitance on the gate side of the field effect transistor, a metal line 5b, an output terminal 6b, and a gap 7b where the metal line parts of the input terminal 1b and the output terminal 6b are adjacent to each other. .

When high-frequency waves propagate through such a line, the gap 7b acts as a capacitor, and the metal line portions 2b, 5
Since b is an inductance, the equivalent circuit becomes a bridging T-type circuit similar to that shown in FIG. 2, and by selecting the values of each element, an all-bandpass circuit can be constructed, and wideband amplification becomes possible.

In addition, the gap capacitance 7b has the two terminals 1b and 6b connected to each other on the same plane and can be formed in the same process as when forming the metal line, so the formation process can be reduced, and pin holes can be eliminated. It is also possible to prevent deterioration of dielectric strength due to such factors, and improve circuit reliability.

In the above embodiment, the metal lines 2b and 5b are circular, but the metal lines 2b and 5b may have an elliptical shape.

〔Effect of the invention〕

As described above, according to the monolithic integrated circuit according to the present invention, it is possible to have 3 #i terminals on the same plane, form a branch circuit having a capacitance between two of the terminals, and use this as a monolithic amplifier. With this configuration, the formation process can be reduced, deterioration of dielectric strength voltage can be prevented, and reliability can be improved.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a full-bend wiring pattern of a branch circuit according to an embodiment of the present invention, Fig. 2 is a diagram showing an equivalent circuit of a branch circuit according to the invention, and Fig. 3 is a diagram showing a metal wiring pattern of a conventional branch circuit. be. 1b is an input terminal, 2b and 5b are inductances due to metal lines, 3b is a connection terminal to the gate side of the field effect transistor, 6b is an output terminal, and 7b is a gap capacitance. In addition, in the figures, the same reference numerals indicate the same or equivalent parts.

Claims (2)

[Claims] (1) Using a branch circuit having three terminals formed on the same plane on a part of the surface of a semi-insulating semiconductor substrate and having capacitive coupling between two of the terminals, inputting each of the above two terminals,
A monolithic integrated circuit comprising a monolithic amplifier configured as an output terminal and a third terminal as a gate connection terminal. (2) The monolithic integrated circuit according to claim 1, wherein the capacitive coupling is coupling by gap capacitance.