JPH04266201A - High frequency transistor - Google Patents

Abstract

PURPOSE:To attain a broad band operation with less circuit loss by covering the surface of the transistor(TR) other than that of the emitter electrode and the base electrode with an oxide film and forming a microstrip line onto the oxide film with metallizing. CONSTITUTION:The TR has regions for an emitter 3, a base 6, and a collector 7 and the surface of the TR except that for an emitter electrode 2 and a base electrode 5 is covered by an oxide film 4, and and microstrip lines 21, 22 are formed on the oxide film 4 by metallizing. Then any impedance conversion circuit is formed on a TR chip by selecting the thickness of the oxide film 4 and the shape of the microstrip lines 21, 22. Thus, the impedance of the TR chip single component is increased and the Q is reduced low.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a high frequency transistor capable of wideband operation.

0002

5 is a plan view showing an example of a conventional high-frequency transistor, and FIG. 6 is a perspective view extracting a part of FIG. The comb portion of the emitter electrode 2 is formed on the emitter region 3, and the emitter electrode is formed from a pad portion. Further, the bonding pad portion of the emitter electrode 2 is formed on the silicon oxide film 4. A base electrode 5 is formed from a comb portion and a bonding pad portion, and the comb portion of the base electrode 5 is formed on the base region 6. Further, a bonding pad portion of the base electrode 5 is formed on the silicon oxide film 4. 7 is a collector area.

FIGS. 7 and 8 are a schematic configuration diagram and a circuit diagram showing a semiconductor integrated circuit using a high frequency transistor having such a configuration. In the figure, reference numeral 8 denotes a metal portion patterned on the substrate surface of the dielectric 9, and this metal portion 8 is connected to the collector electrode of the transistor chip 1. 1
0 is an input lead, 11 is an output lead, 12 is an impedance conversion MOS capacitor, 13 is an input wire connecting the input lead 10 to the impedance conversion MOS capacitor 12, and 14 is an impedance conversion MOS
An input wire connecting the capacitor 12 to the emitter electrode 2, 15 an output wire connecting the metal part 8 to the output lead 11, 16 a ground wire connecting the base electrode 5 to the ground conductor 17, and 18 a bypass MOS capacitor. , 19 connects the metal part 8 to the bypass MOS capacitor 1
A high frequency shunt wire connects up to 8, and 20 is an envelope. Note that the input wires 13 and 14 and the impedance conversion MOS capacitor 12 constitute a low-pass type input-side impedance conversion circuit. In addition, a high frequency shunt wire 19, a bypass MOS capacitor 18
The output wire 15 constitutes a high frequency shunt type output side impedance conversion circuit.

Next, the operation will be explained. Input lead 1
The high frequency signal input to 0 is guided to the impedance conversion MOS capacitor 12 via the input wire 13, and further guided from the impedance conversion MOS capacitor 12 to the emitter electrode 2 via the input wire 14, where it is amplified. The signal is output from the electrode via the output wire 15 and the output lead 11.

[0005]

[Problems to be Solved by the Invention] Since the conventional high-frequency transistor is configured as described above, the impedance of the transistor chip 1 is low and the Q is high, so that there is an impedance near the transistor chip 1 inside the envelope 20. Although a conversion circuit is provided, there is a problem in that there is a limit to widening the band.

[0006] This invention was made in order to solve the above-mentioned problems, and is a high-frequency transistor that enables wide-band operation with low circuit loss by increasing the impedance of a single transistor chip and keeping the Q low. The purpose is to obtain transistors.

[0007]

[Means for Solving the Problems] A high frequency transistor according to the present invention has an emitter, a base, and a collector region,
and an emitter electrode and a base electrode are formed on the surface,
Further, surfaces other than the emitter electrode and the base electrode are covered with an oxide film, and a microstrip line is formed on the oxide film by metallization.

[0008]

[Operation] In the high frequency transistor of the present invention, a microstrip line is formed on an oxide film, and the thickness of the oxide film and the shape of the microstrip line allow any impedance conversion circuit to be formed on the transistor chip. This means that the impedance of a single transistor chip can be increased and Q can be kept low.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view showing the main parts of FIG. 1. In FIGS. are given the same reference numerals and repeated explanation will be omitted. In the figure, 2
Reference numeral 1 denotes a gold electrode for an inductance component formed by metallization on the silicon oxide film 4 of the transistor chip 1, and 22 a gold electrode for a capacitance component formed by metallization on the silicon oxide film 4 of the transistor chip 1. The gold electrode 21 for the inductance component and the gold electrode 22 for the capacitance component form a microstrip line, and an inductance component and a capacitance component are respectively formed depending on the shape of the line and the thickness of the silicon oxide film 4 immediately below.

FIG. 3 is a schematic configuration diagram showing a semiconductor integrated circuit using high-frequency transistors having such a configuration, and FIG. 4 is a circuit diagram thereof. In FIGS. 3 and 4, the same symbols as those in FIGS. 7 and 8 indicate the same configuration. As shown in the figure, a microstrip circuit is connected in series between the collector electrode and the base electrode of the transistor chip 1, and the gold electrode 21 for the inductance component and the gold electrode 22 for the capacitance component are connected to the bypass MOS capacitor 18 and the gold electrode 22 for the capacitance component. Since the high frequency shunt wire 19 is included in the transistor chip 1, the bypass MOS capacitor 1, which was previously required, is
8 and the high frequency shunt wire 19 are no longer required, and the number of parts can be reduced, thereby reducing assembly load and assembly variations. In this case, impedance conversion is performed within the transistor chip 1, so that the impedance of the transistor chip 1 can be kept high and the Q can be kept low.

Next, the operation will be explained. Input lead 1
The high frequency signal input to 0 is guided to the impedance conversion MOS capacitor 12 via the input wire 13, and further guided from the impedance conversion MOS capacitor 12 to the emitter electrode 2 via the input wire 14, where it is amplified. The signal is output from the electrode via the output wire 15 and the output lead 11.

In the above embodiment, a high frequency shunt type circuit configuration is shown, but any other microstrip circuit configuration is possible depending on the shape of the gold electrode and the thickness of the oxide film directly below.

[0013]

[Effects of the Invention] As described above, according to the present invention, a high frequency transistor has an emitter, a base, and a collector region.
and an emitter electrode and a base electrode are formed on the surface,
Furthermore, the surfaces other than the emitter and base electrodes are covered with an oxide film, and a microstrip line is formed on the oxide film by metallization, thereby increasing the impedance of the transistor chip and keeping the Q low. This has the effect of enabling broadband operation with low circuit loss.

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a high frequency transistor according to an embodiment of the present invention.

FIG. 2 is a sectional view showing an extracted main part of FIG. 1;

FIG. 3 is a schematic configuration diagram showing a semiconductor integrated circuit using the high-frequency transistor of FIG. 1;

FIG. 4 is a circuit diagram of FIG. 3;

FIG. 5 is a plan view showing an example of a conventional high-frequency transistor.

6 is a perspective view showing an extracted main part of FIG. 5; FIG.

7 is a schematic configuration diagram showing a semiconductor integrated circuit using the high frequency transistor of FIG. 5. FIG.

8 is a circuit diagram of the semiconductor integrated circuit shown in FIG. 7. FIG.

[Explanation of symbols]

2 Emitter electrode 3 Emitter area 4 Silicon oxide film 5 Base electrode 6 Base area 7 Collector area 21 Electrode for inductance component 22 Electrode for capacitance component

Claims (1)

[Claims] 1. A high-frequency transistor having an emitter, a base, and a collector region, an emitter electrode and a base electrode formed on the surface, and the surface other than the emitter electrode and the base electrode being covered with an oxide film. A high-frequency transistor characterized by a microstrip line formed on an oxide film by metallization.