JPH07240645A - Microwave integrated circuit - Google Patents

Abstract

PURPOSE:To miniaturize a circuit by connecting the microstrip line for the input/output matching circuit to the signal transmission line of an active element, connecting other terminal to the electrode layer of an MIM capacitor and forming a short stub for matching. CONSTITUTION:The source terminal of an active element 1 on a semiconductor substrate is connected to the electrode layer of the surface of the substrate and is electrically connected to the ground electrode on the rear through a via hole 4. On the electrode layer of the surface of the substrate, MIN capacitors 9 and 10 which use the electrode layer as lower part electrode are integrally formed on the via hole 4 and power source lines 7 and 8 for the active element 1 are connected to the upper part electrode (a third electrode layer). Microstrip lines 11 and 12 for input/output matching circuit are connected to the signal transmission lines 2 and 3 of the active element 1; other terminals of these lines 11, 12 are connected to the third electrode layers of the MIM capacitors 9 and 10; and each of short stub for matching is formed. Therefore, the microstrip lines 11 and 12 have both function as the matching circuit and the function as a bias circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a microwave integrated circuit, and more particularly to a monolithic microwave integrated circuit (Mo) used for microwave band amplifiers, frequency converters, oscillators and the like.
nolithic Microwave Integrated Circuit).

In a monolithic microwave integrated circuit, active elements such as field effect transistors (hereinafter abbreviated as FET) and passive elements such as resistors and capacitors are integrated on the same substrate to have a specific function (for example, amplifier). It is a semiconductor device that realizes the above, and can be made smaller and lighter in weight than a hybrid integrated circuit, and because it is manufactured by semiconductor manufacturing technology, it is excellent in mass productivity and can be expected to be low in cost.

By the way, considering the cost reduction of this monolithic microwave integrated circuit, the size of the chip should be as small as possible. Conventionally, FE is used for downsizing
A technique of grounding the source of T using a via hole, and a technique of integrating a capacitor and a via hole as described in JP-A-3-99461, column 2, line 5 to line 8 in order to downsize the bias circuit. Are used.

[0004]

2. Description of the Related Art FIG. 5 is a diagram showing an embodiment of a typical amplifier circuit of a conventional microwave integrated circuit. The circuit shown is formed on the surface of a semiconductor substrate made of gallium arsenide (GaAs), for example. A metal is provided on the back surface of this semiconductor substrate, and serves as a common ground.

Arranged in the center of the drawing is an active element 1 which is a FET and has terminals of a gate G, a source S and a drain D. A signal transmission line 2 for transmitting a main signal is connected to the gate G, and a signal transmission line 3 for transmitting a main signal is also connected to the drain D.
The source S is connected to the electrode layer above the via hole 4, and the active element 1 has a circuit configuration in which the source is grounded.
An input matching circuit 5 and an output matching circuit 6 are connected to each of the signal transmission lines 2 and 3. In addition, the power supply lines 7 and 8 for supplying power to the active element 1 are the signal transmission lines 2 and 3.
The power supply lines 7 and 8 are connected to the power transmission lines 7 and 8 and the signal transmission lines 2 and 3 so that the power supply lines 7 and 8 appear to be open in impedance at the frequency at which the microwave integrated circuit operates. It is grounded in a high frequency manner by MIM (Metal-Insulator-Metal) capacitors 9 and 10 formed on the via holes at the four wavelength lengths.

[0006]

By the way, in a monolithic microwave integrated circuit using a microstrip line as an input / output matching circuit of the circuit, an open stub is often used as the matching circuit. Also, generally, the matching circuit and the bias circuit are realized by separate circuits,
Therefore, a chip area is required for those circuits, and it is difficult to downsize the circuits beyond a certain level.

The present invention has been made in view of the above circumstances, and provides a microwave integrated circuit which has a matching circuit and a bias circuit and can be made smaller than a conventional monolithic microwave integrated circuit. The purpose is to

[0008]

FIG. 1 is a principle diagram of the present invention for achieving the above object. In this figure, the source terminal of the active element 1 provided on the semiconductor substrate is connected to the first electrode layer formed on the front surface of the semiconductor substrate, and the second electrode layer (ground electrode) formed on the back surface thereof. ) Is electrically connected to via the via hole 4. In addition, MIM capacitors 9 and 10 using this as a lower electrode are integrally formed on the via hole 4 on the first electrode layer, and the upper electrode thereof is the third electrode layer. Power supply lines 7 and 8 for supplying power to the active element 1 are connected to the third electrode layer.

Microstrip lines 11 and 12 for an input matching circuit and an output matching circuit are connected to the signal transmission lines 2 and 3 of the active element 1, and the other ends thereof are the third electrodes of the MIM capacitors 9 and 10. Connected to the layers, each forming a matching short stub.

[0010]

According to the above-mentioned means, the microstrip lines 11 and 12 have a function as a matching circuit because they form short stubs and a function as a bias circuit because power can be supplied through them. It will be. Thus, since the matching circuit is integrated with the bias circuit, the required area is smaller than that of the conventional microwave integrated circuit in which these circuits are separately realized.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing an embodiment of the present invention.
In the figure, the active element 1 provided on the semiconductor substrate is T
Shown as a source-grounded FET, which has a gate in the shape of two, has two source terminals, and is electrically connected to the electrode layer of the ground electrode formed on the back surface of the semiconductor substrate through via holes 4 respectively. is there. Therefore, when this microwave integrated circuit is used as an amplifier, the signal transmission line 2 connected to the gate terminal is the signal input side and the signal transmission line 3 connected to the drain terminal is the signal output side.

One end of the microstrip lines 11 and 12 is connected to the signal transmission lines 2 and 3 on the gate terminal side and the drain terminal side of the active element 1, and the other ends thereof are formed on the via holes 4. Capacitors 9, 10
Is connected to the electrode layer that will be the upper electrode of. Also, MI
Power supply lines 7 and 8 for supplying power to the gate and drain of the active element 1 are connected to the electrode layer serving as the upper electrodes of the M capacitors 9 and 10.

According to the above structure, the microstrip lines 11 and 12 form a short stub for matching the input and output, and form a bias circuit for supplying power.

FIG. 2 is a sectional view taken along the line AA of FIG. In this figure, a first electrode layer 101 corresponding to the source terminal of the active element 1 is formed on the surface of the semiconductor substrate 13. The first electrode layer 101 is electrically connected to the second electrode layer 102 formed on the back surface of the semiconductor substrate 13 via the via hole 4 formed in the semiconductor substrate 13.

A thin insulating layer 103 is formed on the surface of the first electrode layer 101, and a third electrode layer 104 is further formed thereon.
Are formed. As a result, the MIM capacitor 10 having the first electrode layer 101 as the lower electrode, the insulating layer 103 as the capacitor dielectric, and the third electrode layer 104 as the upper electrode is formed.

Further, a matching microstrip line 12 is formed on the surface of the semiconductor substrate 13, and between the microstrip line 12 and the MIM capacitor 10, the end of the microstrip line 12 and the third electrode layer are formed. It is electrically connected by an air bridge 14 that connects the air conditioner 104. As a result, the short stub is formed, and the microstrip line 12 can be used as a power supply line which is supplied by relaying the third electrode layer 104.

FIG. 3 is a diagram showing another embodiment of the present invention. According to this figure, the circuit of the active element 1 shown in FIG.
That is, the source terminal of the active element 1 is the signal transmission line 2,
There are two circuits that are grounded on both sides with respect to 3, and these are MIM capacitors 15 for cutting the DC component.
Are connected in series to form a two-stage configuration.

According to this configuration, the first-stage matching microstrip line 12 and the second-stage matching microstrip line 11 are arranged on both sides of the signal transmission lines 2 and 3, that is, the signal transmission lines 2 and 3. Since they are spatially separated by the transmission lines 2 and 3, the electromagnetic coupling between the microstrip lines can be reduced, and thus the distance between the stages can be reduced. Further, the matching circuit forms a short stub by the microstrip lines 11 and 12 and the MIM capacitors 9 and 10, and the short stub itself is less susceptible to electromagnetic influence than when the open stubs are close to each other. It becomes possible to arrange the devices closer to each other, which facilitates miniaturization of the circuit. This is not limited to two stages as in the illustrated example, but can be applied to a multistage connection structure.

FIG. 4 is a diagram showing still another embodiment of the present invention. In the figure, the active element 1 provided on the semiconductor substrate has an I-shaped gate structure, and therefore has only one source terminal, and the electrode layer of the ground electrode formed on the back surface of the semiconductor substrate through the via hole 4. Electrically connected to.

On the first electrode layer formed on the via hole 4, a third electrode layer is divided into two via an insulating layer. That is, the two MIM capacitors 9 and 10 sharing the lower electrode and the dielectric are connected to the via hole 4.
Will be formed on top of. Matching microstrip lines 11 and 12 are connected to the third electrode layers, which are the upper electrodes of the MIM capacitors 9 and 10, by air bridges to form a matching circuit.
Power supply lines 7 and 8 are also connected to the third electrode layer so that power is supplied to the active element 1 through the microstrip lines 11 and 12.

[0021]

As described above, according to the present invention, the matching circuit has a short stub structure, the MIM capacitor forming the short circuit portion of the short stub is formed on the via hole 4, and the upper electrode of the MIM capacitor is biased. The circuit is configured as a relay terminal. For this reason,
The matching circuit and the bias circuit can be formed by a common microstrip line, and the via hole 4
Since it is possible to reduce the number of MIM capacitors formed on the upper part, it is possible to easily miniaturize the circuit.
Moreover, since electromagnetic coupling between circuit elements generated by miniaturizing the circuit can be reduced, the microwave integrated circuit can be further miniaturized.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along the line AA of FIG.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing yet another embodiment of the present invention.

FIG. 5 is a diagram showing an example of a typical amplifier circuit of a conventional microwave integrated circuit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 active element 2 and 3 signal transmission line 4 via hole 7 and 8 power supply line 9 and 10 MIM capacitor 11 and 12 microstrip line 13 semiconductor substrate 14 air bridge 101 1st electrode layer 102 2nd electrode layer 104 3rd electrode layer

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical display location H01P 1/00 Z 3/08 H03H 7/38 (72) Inventor Tamio Saito Hodogaya Ward, Yokohama City, Kanagawa Prefecture Kobe-cho 134 Milliwave Co., Ltd.

Claims (3)

[Claims] 1. An active element (1) provided on a semiconductor substrate and a first electrode layer formed on the front surface of the semiconductor substrate and connected to a source terminal of the active element are formed on the back surface of the semiconductor substrate. A via hole (4) electrically connected to the formed second electrode layer, a thin insulating layer formed on the first electrode layer and the first electrode layer, and a thin insulating layer formed on the insulating layer. A third integrated electrode layer and at least one MIM capacitor (9, 10) integrally formed on the via hole, wherein one end is connected to the signal transmission line of the active element. , The other end is connected to the third electrode layer of the MIM capacitor to form a short stub for matching, and a power line for applying power to the active element is connected to the third electrode layer for input. And out Microwave integrated circuit, characterized in that it comprises a microstrip line (11, 12) which also serves as a matching circuit and a bias circuit. 2. The active element (1) has a structure in which the source terminals are arranged on both sides of the signal transmission line, and the microstrip line (11, 12) for an input and output matching circuit. 3. The microwave integrated circuit according to claim 1, wherein the other end is connected to the third electrode layer of the MIM capacitor arranged on both sides of the signal transmission line. 3. The active element (1) has a structure having one source terminal thereof, and the microstrip lines (11, 12) for an input and output matching circuit are provided on the via hole having one other end. The two MIs located in
2. The microwave integrated circuit according to claim 1, wherein the microwave integrated circuit is configured to be connected to each of the third electrode layers of the M capacitors.