JP2609767B2 - Semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device, and more particularly to a semiconductor device having a GaAs field effect transistor (hereinafter referred to as a GaAs MES FET) operated in a microwave frequency band.

[0002]

2. Description of the Related Art A conventional semiconductor device having a GaAs MES FET is, as shown in FIG.
A ceramic or metal plate-like cap 2 is sealed on the upper surface of the side wall with a solder such as AuSi. This package is connected to a waveguide (as the frequency increases,
The dimensions of the package are designed on the assumption that the electromagnetic waves pass through a hollow conductor tube), but the strip line 5 and the chip capacitor 6 are provided inside the package so as to obtain 50Ω matching in the microwave frequency band. Since such a dielectric material is mounted, the dielectric constant of the hollow is reduced, and the practical frequency of the package is reduced.

FIG. 3 is a diagram showing an example of a practical frequency characteristic of a package. The practical frequency of this package is a frequency at which an isolation loss of 40 dB can be obtained.

[0004]

In this conventional semiconductor device, when a 50Ω internal matching circuit is formed near the practical frequency limit of the package, the isolation of the package itself becomes insufficient, and the mismatch between the internal input and output is reduced. This has the drawback of causing deterioration of characteristics. That is,
Frequency f at which the isolation shown in FIG.
Is the resonance circumference calculated from the planar shape of the package.
Correction of wave number (TM ₁₁₀ mode) F by filling state inside
It is a value obtained by multiplying the coefficient K (K <1).
Dielectric chip capacitors and stripline substrates occupy
Volume occupied by hollows with low dielectric constant relative to volume
The correction coefficient K becomes smaller and the frequency f decreases.
You. For example, even if F = 15 GHz, K = 0.8, and f is
The frequency drops to 12 GHz, and frequencies below 12 GHz are
Practical frequency that can be used practically because it can take 40dB
However, frequencies higher than 12 GHz are isolated.
Cannot be put to practical use because 40 dB cannot be obtained.

[0005]

According to the present invention, there is provided a semiconductor device comprising:
A semiconductor chip mounted on the inside bottom of the package, the
Chips provided on the input side and output side of the semiconductor chip respectively
Capacitor and the outside of the chip capacitor.
And a strip line outside the strip line.
The respective side walls of the package and in front of each
Connected to the strip line and penetrated through the side wall to the outside
In a semiconductor device having a 50Ω internal matching GaAs field-effect transistor for performing electrical matching in a microwave frequency band including a lead led out one by one and a cap for sealing the package, the upper surface of the side wall and the cap A frame-shaped spacer is provided between
The chip is connected to the pair of chip capacitors from above the semiconductor chip.
On the sensor and on the pair of strip lines
It has a flat shape up to the upper surface of the wall.

[0006]

Next, the present invention will be described with reference to the drawings.

FIGS. 1A and 1B are a partially cutaway perspective view and a perspective view of a spacer showing an embodiment of the present invention.

As shown in FIGS. 1A and 1B, a semiconductor chip 7 mounted on the inner bottom of the package 3 and a chip capacitor provided on the input and output sides of the semiconductor chip 7 and connected to the semiconductor chip 7 6, a strip line 5 provided on the input side and an output side of the chip capacitor 6, a lead 4 which is connected to each of the strip lines 5 and penetrates through the side wall 9 of the package 3 and extends to the outside, and a side wall of the package 3. It comprises a spacer 1 made of frame-shaped oxygen-free copper provided on the upper surface and having a gold plating layer on the surface, and a cap 2 provided on the spacer 1 to seal the package 3.

[0009]

As described above, according to the present invention, by providing a spacer between the upper surface of the side wall of the package and the cap, the practical frequency of the package is matched and the isolation between the input / output circuits is sufficiently ensured. In this way, it is possible to prevent a mismatch between input and output when configuring an internal matching circuit in the microwave frequency band in the vicinity of the practical frequency limit of the package, and to realize a stable 50Ω internally matched GaAs MES FET with small loss. Has an effect. That is, even if the other configuration is the same as FIG.
In FIG. 1, a chip capacitor having a high relative dielectric constant is provided.
Low ratio to the volume occupied by the
The volume occupied by the hollow of the electric power increases and the correction coefficient K becomes, for example,
0.9 to 0.95, the frequency at the practical frequency limit
The number f is as high as 13.5 GHz to 14.25 GHz
Can be Also required frequency and three-dimensional implementation
By selecting spacers in consideration of both the degree of integration
Even if the package body and cap are the same,
The conductor device can be dealt with, and the productivity is improved.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view and a perspective view of a spacer showing an embodiment of the present invention.

FIG. 2 is a partially cutaway perspective view showing an example of a conventional semiconductor device.

FIG. 3 is a diagram illustrating an example of a practical frequency characteristic of a package.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Spacer 2 Cap 3 Package 4 Lead 5 Strip line 6 Chip capacitor 7 Semiconductor chip 9 Side wall

Claims (1)

(57) [Claims] 1. A semiconductor chip mounted on an inner bottom of a package, and an input side and an output side of the semiconductor chip, respectively.
And the chip capacitor provided outside the chip capacitor
A strip line provided on each side and the strip
Side walls of the package respectively located outside the tracks
And the side walls connected to the respective strip lines.
, And leads led out one by one to the outside,
A 50Ω internal matching GaAs for providing electrical matching in a microwave frequency band with a cap for sealing the package.
In a semiconductor device having an s field effect transistor, a frame-shaped spacer is provided between an upper surface of the side wall and the cap.
And the cap is placed on the semiconductor chip from above
On a pair of chip capacitors and said pair of strip lines
It becomes a flat shape up to the upper surface of the side wall through the road
Wherein a is.