Amplifiers – Signal feedback – Combined with control of bias voltage of signal amplifier
Patent
1980-08-20
1984-01-24
Edlow, Martin H.
Amplifiers
Signal feedback
Combined with control of bias voltage of signal amplifier
357 51, 330307, 330286, 330277, 333247, H01L 2302
Patent
active
044279914
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
This invention relates to a high frequency semiconductor device, and more particularly, to a structure of the high frequency semiconductor device which provides a circuit substrate for mounting active elements such as transistors, passive elements such as capacitors and resistors and a package for accommodating the circuit substrate, and handles a high frequency signal such as a microwave signal.
BACKGROUND ART
A high frequency semiconductor device, such as a microwave amplifier, provides a circuit substrate for mounting active elements such as transistors, passive elements such as capacitors, resistors and inductors, and a package for accommodating them.
Within the existing art, in order to form a high frequency semiconductor device such as a single-stage microwave amplifier, a transistor, which is hermetically sealed to prevent degradation of its characteristics and which is provided with leads to connect to other circuit elements, is mounted on a circuit substrate. The transistor is connected with the other elements which are also mounted on the same circuit substrate and are required for the formation of an amplifier. The circuit substrate is housed in a metal case.
Some of the various elements fixed on the substrate and forming the amplifier, such as transistors, are individually, hermetically sealed and as a result occupy a great deal of space. Thus, a large circuit substrate and an appropriately large case are required in order to mount such an amplifier.
In a situation involving a multi-stage amplifier the size of the total device is quite large because the device consists of a plurality of large, interconnected circuit substrates mounting hermetically sealed containers.
In the existing method for coping with this disadvantage transistor chips are mounted together with the other necessary circuit elements on the substrate formed on the metal base. The transistor chips are not individually hermetically sealed. Rather, all the circuit mounting substrates are accommodated in one metal case which is hermetically sealed. Such a structure has the advantage that physical dimensions are reduced as compared with the existing multi-case structure. However, at the same time it has the disadvantage that perfect sealing becomes difficult because the size of the seal is substantially greater for the entire metal case than for the structures in which individual transistors are hermetically sealed.
SUMMARY OF THE INVENTION
An object of the present invention lies in offering a high frequency semiconductor device which is compactly designed as an entire unit, even for a multi-stage arrangement, and has sufficient hermetical sealing.
Another object of the present invention lies in offering a high frequency semiconductor device which comprises a plurality of high frequency semiconductor amplifiers, directly cascade-connected, without intervention of any elements, so as to form a multi-stage amplifier circuit.
The present invention offers a high frequency semiconductor device which is small in size and has sufficient sealing. The device can easily be used for assembling a system by providing:
(1) a metal base substrate on which are mounted a function device having at least one semiconductor element, a DC circuit for operating said semiconductor element and a high frequency circuit which is used for cascade-connecting the semiconductor element with an external circuit, and which is also used as the ground electrode for a high frequency component; (2) an insulating substrate which surrounds the function device in the form of a frame and simultaneously provides a plurality of independent metallized parts for connection with the external circuits at its surface; and (3) a sealing part for hermetically sealing the function device.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the uncovered outline of a high frequency semiconductor device of the present invention.
FIG. 2 shows a metal base substrate 1. FIG. 2A is a plan view, while FIG. 2B is a cross-section along the line A--A'
REFERENCES:
patent: 3940706 (1976-02-01), Stegens
patent: 3958195 (1976-05-01), Johnson
patent: 4259684 (1981-03-01), Dean
Hidaka Norio
Kosemura Kinjiro
Shima Takao
Yamamura Shigeyuki
Edlow Martin H.
Fujitsu Limited
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