JPS6348855A - Monolithick microwave integrated circuit - Google Patents

Abstract

PURPOSE:To reduce the area of a bias circuit device and to implement high integration density and reduction in chip price as a result, by forming an inductor on an insulating film formed on a substrate electrode, and constituting the bias circuit part. CONSTITUTION:An inductor 5 is formed on an insulating film 11, which is continuously deposited and formed on a substrate electrode 10. A capacitor is formed between the inductor 5 and the substrate electrode 10. Therefore, the area of a bias circuit part can be reduced. As a result, an IC chip can be integrated, and the price of the chip can be made low.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a monolithic microwave integrated circuit (hereinafter abbreviated as MMIC) that operates in an ultra-high frequency band on the UHF band.

[Conventional technology]

FIG. 3 is an equivalent circuit diagram of a commonly used MMIC. In this figure, 1 is a gallium arsenide field effect transistor (hereinafter abbreviated as FET) which is an active circuit part formed in the MMIC, 2 is a drain terminal of the FETI,
3 is a bias circuit section for applying a DC bias to the drain terminal 2, and includes an inductor 5 for blocking microwaves.
and a capacitor 6, and by designing the inductance value of the inductor 5 and the capacitance value of the capacitor 6 to desired values, leakage of the microwave signal to the bias power supply terminal 7 is prevented. Note that 4 is a microwave circuit section provided between the bias circuit section 3 and the FETI.

Further, FIG. 4 is a plan view of a surface backplane showing the structure when the bias circuit section 3 of FIG. 3 is realized on an MMIC. In this figure, the same reference numerals as in FIG. 3 indicate the same parts, 8 is a metal bridge, 9 is an upper electrode, 10 is an underlayer electrode, and 11 is an insulating film.

That is, in this configuration, a loop-shaped inductor 5 formed on a semi-insulating gallium arsenide substrate and a parallel plate type capacitor 6 are electrically connected by a metal bridge 8 manufactured by an electroplating method or the like. Here, the capacitor 6 is composed of an upper electrode 9 having a K ground To t%, a base electrode 10 connected to the bias power supply terminal 7, and an insulating film 11 sandwiched between the upper electrode 9 and the base electrode 1°. M
(M etal -I n5ulator M etal
al) [It is constructed.

[Problem that the invention seeks to solve]

In the conventional MMIC as described above, since the microwave blocking inductor 5 and capacitor 6, which are large in size, are each configured separately, the area occupied by the bias circuit section 3 in the MMIC depth becomes significantly large. This becomes an impediment to reducing the chip area, and therefore poses problems such as making it difficult to reduce the price of the IC.

The present invention has been made to solve this problem, and aims to provide an MMIC which can reduce the area of the bias circuit section and, as a result, achieve a highly integrated 2-chip price reduction for the MMIC. purpose.

[Means for Solving the Problems] The MMIC according to the present invention has a bias circuit section formed by forming an inductor on an insulating layer formed on a base electrode.

[Effect]

In this invention, a capacitor is formed between the inductor and the base electrode.

〔Example〕

FIG. 1 is a perspective view showing an embodiment of a bias circuit section of an MMIC according to the present invention. In this figure, the same reference numerals as in FIG.

That is, in the present invention, since the inductor 5 is formed on the insulating film 11 that is continuously deposited on the base electrode 1o, a capacitance is formed between the inductor 5 and the base electrode 10. Therefore, it is possible to reduce the area of the bias circuit section.

In this case, the bias circuit section is constructed using the coupling capacitance CI per unit inductor length and the inductance value between the loop-shaped metal pattern forming the inductor 5 and the base electrode 10, as shown in the equivalent circuit diagram of FIG. Express it approximately as shown in .

In general, the coupling capacitance C, depends on the material and film thickness of the insulating film 11, and the inductance value L1 depends on the line width W of the loop-shaped metal forming the inductor 5.

Each can be determined by the line spacing and the number of turns n, and by setting the coupling capacitance CX and the inductance value L1 to desired values, the power reflection coefficient in the operating frequency band viewed from the terminal 12 to the power supply circuit side can be reduced to almost 1. can be designed.

That is, the bias circuit can be used as a microwave blocking circuit.

In the above embodiment, the bias circuit section for applying the drain voltage of the FET was explained, but the same effect can be obtained even if it is used as the bias circuit section for applying the gate voltage or for the active circuit of other MMICs such as a diode. It goes without saying that it would become Qin.

Further, in the above embodiment, a loop-shaped inductor is used as the inductor, but it goes without saying that a meander-shaped inductor or a rod-shaped inductor may be used.

〔Effect of the invention〕

As explained above, this invention has the effect of forming a bias circuit section by forming an inductor on an insulating film formed on a base electrode, so that IC chips can be integrated, and as a result, the chip price can be reduced. There is.

[Brief explanation of drawings]

1 is a perspective view showing an embodiment of the bias circuit section of an MMIC according to the present invention, FIG. 2 is an equivalent circuit diagram of the bias circuit section according to the present invention, FIG. 3 is an equivalent circuit diagram of a conventional MMIC, and FIG. The figure is a plan view showing the configuration of a conventional bias circuit section. In the figure, 5 is an inductor, 8 is a metal bridge, 10
11 is a base electrode, 11 is an insulating film, and 12.13 is a terminal. Note that the same reference numerals in each figure indicate the same or corresponding parts. Agent Masu Oiwa 1a (2 others) Figure 1 Figure 2 Figure 3 Figure 4

Claims (1)

[Claims] A monolithic microwave integrated circuit comprising a bias circuit section consisting of an inductor and a capacitor, characterized in that the bias circuit section is configured by forming the inductor on an insulating film formed on a base electrode. Microwave integrated circuit.