JPH073827B2 - High frequency semiconductor device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a high-frequency semiconductor device in which a FET and a strip line are integrally formed on a compound semiconductor substrate such as GaAs.

Conventional technology At a high frequency of 10 GHz or more, a stripline can be formed compactly by using a semi-insulating GaAs substrate as a dielectric.
Even if it is integrally formed on the board, the chip size does not become so large, and the impedance matching circuit made up of strip lines can raise the input / output impedance to 50Ω, making it possible to construct a high-frequency circuit with low loss. Become. In this type of high-frequency semiconductor device in which a FET and a strip line are integrally formed on a semi-insulating GaAs substrate, the strip line is composed of a line formed on the surface and having a constant width for obtaining a predetermined characteristic impedance and a back electrode. To be done. Therefore, when measuring the high frequency characteristics of a chip in which an FET and a strip line are integrally formed on a semi-insulating GaAs substrate, it is necessary to use the strip line located on the front surface side and the back surface electrode on the back surface of the chip. However, in the conventional chip of this type, only the input side strip line and the output side strip line are provided on the chip surface, and the grounded electrode is not formed on both sides or one side of the strip line of the input end and the output end. Therefore, it becomes extremely difficult to measure the input / output impedance at the end of the chip.
It was measured after it was assembled in a package or the like, and the measurement error was large and the reliability was insufficient, so it was extremely difficult to accurately measure the impedance at the chip end.

FIG. 2 shows a high frequency semiconductor device in which a FET and a strip line are integrally formed on a conventional semi-insulating GaAs substrate. Second
In the figure, the input-side matching circuit 1 is connected to the gate terminal G, and the output-side matching circuit 2 is connected to the drain terminal D. It works to raise the input and output impedances of the FET3 to around 50Ω, and to suppress the loss due to impedance mismatch. To do.
The input side matching circuit 1 and the output side matching circuit 2 are semi-insulating GaAs.
Although not shown in FIG. 2, a strip line is formed between the main surface of the substrate 4 and the semi-insulating GaAs substrate 4 as a dielectric, and a back electrode formed on the back surface of the semi-insulating GaAs substrate. Is configured. The input signal enters from the chip end of the input side matching circuit 1, is amplified by the FET 3, passes through the output side matching circuit 2, and is drawn out from the end thereof. The terminal S is the source terminal of the FET3 connected to the back surface electrode using the V groove.

Problems to be Solved by the Invention In the conventional high frequency semiconductor device shown in FIG. 2, when the high frequency characteristics of the chip are measured, the chip is actually assembled in a package or the like, and the input end and the output end of the chip are bonded with bonding wires. Measurement is possible only after connecting. Therefore, it is extremely difficult to evaluate the high frequency characteristics before assembling into a package, that is, in a wafer state or a chip state. In addition, the high-frequency performance such as input / output impedance when assembled in a package using bonding wires, etc., has a very large error, and is large when an external impedance matching circuit is designed and the impedance is set to 50 Ω. This caused an error and caused impedance mismatch.

The present invention has been made in view of the above points, and an object thereof is to provide an excellent high-frequency semiconductor device having a configuration capable of accurately measuring high-frequency characteristics such as input and output impedances of a chip end without assembling. There is.

Means for Solving the Problems In order to solve the above problems, in the high frequency semiconductor device in which the FET and the strip line are integrally formed on the main surface of the same compound semiconductor substrate, the input end of the strip line on the input side is On both sides or one side and on both sides or one side of the output ends of the strip lines on the output side, surface ground electrodes electrically connected to the back side electrodes formed on the opposite main surface side of the substrate are arranged.

Operation The present invention makes it possible to measure high-frequency characteristics such as an input / output impedance in a wafer state or a chip state without error without assembling the chip on a package using a bonding wire with the above configuration.
Further, when a matching circuit is provided outside the chip, the impedance at the end of the chip can be measured accurately, so perfect matching of 50Ω becomes possible.

EXAMPLE FIG. 1 is a plan view and a sectional structure view showing an example of the high-frequency semiconductor device of the present invention. In FIG. 1, components equivalent to those in FIG. 2 are designated by the same reference numerals and symbols. In the embodiment of the present invention shown in FIG. 1A, the input matching circuit 1 and the output matching circuit 2 are integrally formed on the input and output sides of the FET 3 on the main surface of the semi-insulating GaAs substrate 4. Both sides of the strip line at the input end and the output end are
The surface ground electrode 5 is arranged. The surface ground electrode 5 is
It is electrically connected to the back surface electrode through the V groove 6. FIG. 1B shows a sectional view taken along the line AA ′ of FIG. In FIG. 1B, the strip line front surface electrode 7 is located at the center of the surface ground electrode 5, and the surface ground electrode 5 is electrically connected to the strip line back surface electrode 8 through the V groove 6. . Therefore, when measuring the impedance of the input end and output end of the chip, it is possible to measure from the surface side using a high frequency prober etc. in the wafer state or the chip state without assembling the chip with the bonding wire. Become. Further, since the input / output impedance at the end of the chip can be measured accurately, the design becomes very easy even when a matching circuit is provided outside.

The distance between the surface ground electrode 5 and the strip line surface electrode 7 is 30
If it is about μm, it does not affect the high frequency.

The present invention can be applied to compound semiconductors other than GaAs.

Effects of the Invention As described above, the present invention has the following effects.

(1) Since the surface ground electrode connected to the back surface electrode is arranged at the input end and the output end of the chip, it is possible to accurately measure the high frequency characteristics such as the impedance of the input end and the output end from the front surface side. Therefore, there is no need to assemble and evaluate using bonding wires or the like.

(2) Since the impedance at the input end and the output end of the chip can be accurately measured, the design of the matching circuit outside the chip becomes easy.

[Brief description of drawings]

FIG. 1 (a) is a plan view showing an embodiment of the high frequency semiconductor device of the present invention, FIG. 1 (b) is a sectional view taken along the line AA 'of FIG. 1 (a), and FIG. It is a top view which shows a high frequency semiconductor device. 1 ... Input side matching circuit, 2 ... Output side matching circuit, 3 ...
FET, 4 ... Semi-insulating GaAs substrate, 5 ... Surface ground electrode,
6 ... V groove, 7 ... Stripline front surface electrode, 8 ... Stripline back surface electrode.

Claims (2)

[Claims] 1. An FET and a strip line are integrally formed on a chemical semiconductor substrate, and at least one side of an input end of the input side strip line located on the main surface side of the compound semiconductor substrate and an output of the output side strip line. A high frequency semiconductor device having a surface ground electrode electrically connected to a back surface electrode formed on the opposite main surface side of the substrate on at least one side of the end. 2. A high frequency semiconductor device according to claim 1, wherein the front surface ground electrode is electrically connected to the back surface electrode through a groove provided in the substrate.