JPS5838615Y2 - High frequency semiconductor device - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improved structure of an envelope for a high frequency semiconductor device, particularly for a semiconductor device used at high frequency and high output.

The performance of high-output, high-frequency transistors has improved significantly in recent years, and 2GH2 can now provide outputs reaching 20W.

The reasons that have made this possible are not only advances in semiconductor process technology but also significant improvements in high-frequency envelopes, which can be broadly classified into the following improvement methods.

0) Use of low-loss materials, (2) Gradual reduction of emitter inductance, (3) Gradual reduction of return capacitance, (4) Internal matching method,
(5) Gradual decrease in thermal resistance.

Regarding the above, the specific measures for 1.(1) are to use ceramics with low high frequency loss as the envelope material;
A method of gold plating the external terminals is generally used.

The following method (2) is used to prevent a decrease in the gain of the transistor and prevent parasitic oscillations.
-131467).

As for (3), a method of applying an electrostatic shield to gradually reduce the return capacitance has been proposed (for example, Japanese Patent Laid-Open No. 49-115277 and Japanese Patent Laid-Open No. 50-57383).

(4) has a matching circuit inside the envelope, and uses a Moss capacitance...The hybrid type is U.S. Patent No. 37
It is shown in the specification of No. 13006.

Recently, a modification using the inductance of the bonding wire has been published in the Microwave Journal (Apr. 1978, pp. 81-84).

Furthermore, a method of internal matching using strip lines is described in Japanese Utility Model Publication No. 45-33452.

(5) is a common problem with high-power transistors.

Beryllia porcelain is often used for the envelope of high-frequency transistors. Various ideas related to this are detailed in the above-mentioned publications and documents, so a description thereof will be omitted.

Although the various improvements described above have been made and the performance of the envelope has improved, it has been confirmed that the following problems occur in current high frequency, high output transistors.

The phenomenon will be explained below, and it will be explained that the above-mentioned conventional techniques cannot solve the phenomenon.

As a method for increasing the output power of a transistor, as shown in a perspective view in FIG. 1 and a top view in FIG.
A widely used method is to mount two or more pellets of the same type 2,2' or more inside one envelope, a part of which is shown in 1 in the figure, and to electrically operate them in parallel.

Although it is not possible to obtain twice the output with this method, it is actually possible to obtain 1.
4 to 1.6 times more output can be obtained.

Ta! The above is for HF' band (1~30MHz) and VHF.
It is very effective for transistors in the band (particularly 30 to 175 MHz).

However, when looking at the input/output characteristics of transistors used at frequencies higher than the above frequency, such as the UHF band, an abnormal phenomenon as shown in FIG. 3 occurs.

That is, in Figure 3, the horizontal axis shows the high frequency input power (PIN), and the vertical axis shows the high frequency output power (Po) in units (W).As the high frequency input increases from zero, the output increases to A. It increases from point B and increases through point B.

In the case of normal characteristics, as the input increases, it passes through point C and finally reaches point D, where it is saturated.

However, there are cases where the output suddenly decreases from point C to point E.

1\ If the input is left uncut, the output will further decrease and move to point F9, and eventually break down, or if the input is increased from point E, it will move to point G, and other abnormal characteristics. occurs.

The cause of this phenomenon can be explained from the equivalent circuit shown in FIG.

This figure shows a portion where a transistor having the characteristics shown in FIG. 3 is mounted, with particular attention to inductance.

In order for transistors to ideally operate in parallel, Pellet B is required.
, 2', and also that the common terminal of the bonding wire 10b1 on the input side (for connecting the base terminal 3 and the base electrode of the pellet) It is desired that the inductance of the bonding wire 10e1 on the side of the terminal connected to the same potential by the bridging conductor 6 that straddles the deriving member 5 and of the bridging conductor 6 is uniform and free of variation.

However, in reality, although there are variations, wires (LBl, LB2 and LEI) are used for J■ band and VHF' band.
, LE2) due to variations in length, etc., can be ignored, and the two transistors (T1, T1,
T2) operates normally in parallel.

However, when it is on UHFHF, and the transistor has a high output and the input/output impedance decreases by %1jlvc, the conventional method requires a longer wire and the inductance of the wire becomes more important than the impedance of the transistor, and due to this variation, the transistor becomes unbalanced. It becomes impossible to operate in parallel.

The point C where the abnormal phenomenon occurs differs depending on the type of transistor, but the fact that it tends to be close to the saturated output of one pellet supports that the burden is on one of the two pellets. .

Conventional envelopes do not have sufficient countermeasures to counteract this phenomenon by operating two transistors in balanced parallel operation.

This invention provides a high frequency semiconductor device having a structure that improves the above-mentioned conventional drawbacks.

The high-frequency semiconductor device of this invention has an envelope structure that enables stable parallel operation by installing two or more transistors in the same envelope without causing abnormal phenomena between high-frequency input and output. It has the following characteristics.

Next, this invention will be explained in detail with reference to the drawings for one embodiment of a high frequency semiconductor device.

In FIG. 5, which shows a top view of a state in which a semiconductor element is mounted on an envelope, reference numeral 11 denotes a part of the envelope, and the collector electrode metallized layer 31C1 is deposited on the upper surface of the dielectric substrate 21.
Base electrode metallization layer 31b1 Emitter electrode metallization layer 31
A collector terminal 41c1, a base terminal 41b1, and an emitter terminal 41e, 41e' are disposed via terminals e and 31e', respectively.

Furthermore, the arrangement of each of the electrode metallization layers on the dielectric substrate will be explained next.

1. First, the collector electrode metallized layer 31c is formed and deposited in a concave shape with parallel stripes 311c and 312c protruding from the base layer 310c, and the semiconductor element pellet 1 is attached to the parallel stripes.
2.12' are connected at their collector electrodes.

Next, the base electrode metallization layer 31b has a base layer 310b provided on the dielectric substrate opposite to the base layer 310c of the collector, and a protruding strip 311b is formed between the parallel strips 311c and 312c of the collector. This results in a parallel and non-contact plunge.

The emitter electrode metallization layers 31e and 31e' are provided between the collector and base electrode metallization layers at the peripheral edge of the dielectric substrate, and are sandwiched between the collector and base electrode metallization layers from a direction perpendicular to the parallel strips of the collector in a non-contact manner. It is formed into a shape.

The metallized layers 31e and 310' are connected by a metal wire 20 extending over the main surface of the dielectric substrate in the gap between the electrode metallized layers of the collector and base, and are maintained at equal potential. .

Note that 30, 30', . . . are thin bonding wires that connect the electrodes (emitter, base) of the semiconductor element to the corresponding electrode metallization layers 31e, 31b.

One! A high frequency semiconductor device is achieved by forming an envelope using synthetic resin.

FIG. 6 shows several circuits of the high frequency semiconductor device having the above structure.

Protruding striations 31 from the base layer in the base electrode metallization layer
Due to the action of 1b, the length of the base bonding wire 30' can be made extremely shorter than in the conventional case, and the variation due to the inductance LB11°LB2' is reduced.

In addition, emitter inductance LEI', LE2'
Since it is not connected to the bridging conductor 6 (FIGS. 1 and 2) as in the conventional case, the number is reduced accordingly.

Furthermore, since the two pellets are physically separated, the mutual inductance between each bonding wire is gradually reduced, and the heat generation sources are thermally dispersed, reducing mutual influence and lowering the bonding temperature. It also has the feature of being able to operate in

Although the above description has been made by exemplifying a common emitter transistor, the same explanation applies to a common base transistor.

However, it can be applied to field effect transistors, etc., and similar effects can be obtained.

Furthermore, in order to increase the number of disposed pellets, for example, the parallel stripes of the collector electrode metallized layer formed in a concave shape and the protruding stripes of the base electrode metallized layer that protrude between the parallel stripes are formed to be long. , a plurality of pellets can be provided on the parallel stripes, and the effect is still effective.

The high-frequency semiconductor device of this invention is easy to implement and has excellent electrical characteristics, and since the mount assembly does not have a three-dimensional part like a conventional bridging conductor and is a flat arrangement, there are no accidents during assembly. It has a strong structure with few short-circuit accidents after manufacturing.

[Brief explanation of the drawing]

Figures 1 and 2 both show the mounting structure of a conventional high-frequency semiconductor device. Figure 1 is a perspective view, Figure 2 is a top view, and Figure 3 shows the input and output of a transistor in the high frequency range. 4 is an equivalent circuit diagram of a high frequency semiconductor device, FIG. 5 is a top view showing a mounting structure of a high frequency semiconductor device according to an embodiment of the present invention, and FIG. 6 is a diagram for explaining the relationship.
The figure is an equivalent circuit diagram of a high frequency semiconductor device according to an embodiment of the present invention. Note that the same reference numerals in the drawings indicate the same or corresponding parts. DESCRIPTION OF SYMBOLS 11... Envelope, 21... Dielectric substrate, 31b... Base electrode metallization layer, 31e, 3
1e...Emitter electrode metallization layer, 31c.
...Collector electrode metallized layer, 41b...
Base terminal, 41e, 41e'... Emitter terminal, 41C... Collector terminal, 310b.
...Base layer of base electrode metallization layer, 311b...
...Protruding stripes of base electrode metallized layer, 310c...
...Base layer of collector electrode metallization layer, 311c, 3
12c...Parallel strips of collector electrode metallized layer,
12, 12'... Semiconductor element, 20...
・Metal line connecting between both emitter electrode metallization layers, 30
．． 30'... Bonding thin wire connecting the electrode of the semiconductor element and the electrode metallization layer.

Claims (1)

[Scope of utility model registration request] a dielectric substrate, a collector electrode metallized layer having parallel stripes formed on the substrate, and a base having a protruding extra portion that protrudes between the parallel stripes of the collector electrode metallization layer without contacting the parallel stripes. An electrode metallization layer and an emitter electrode metallization layer formed in a shape sandwiching the parallel stripes of the collector electrode metallization layer in a non-contact direction from a direction perpendicular to the parallel stripes of the collector electrode metallization layer are provided between the emitter W metallization layer. A connecting conductor, a semiconductor element pellet fixed by a collector electrode to the parallel stripes of the collector electrode metallized layer, and an emitter electrode and a base electrode of the semiconductor element pellet connected to the respective metallized layers opposite thereto. A high frequency semiconductor device equipped with a bonding wire.