JPH07120906B2 - Microwave millimeter wave high power transistor - Google Patents

Description

Description: FIELD OF THE INVENTION The present invention relates to microwave millimeter wave devices, and more particularly to high power transistors.

[Conventional technology]

Ga as a high-power amplifier in the microwave and millimeter-wave band
Development of unipolar devices and bipolar devices using various compound semiconductor materials such as AsFET, InPFET, AlGaAs / GaAsHBT is progressing. In order to increase the output of such a semiconductor device, it is usual to arrange a large number of unit devices in parallel.

FIG. 3 is a plan view of a conventional high-power GaAs FET. A Schottky gate electrode 43 made of A1 is formed on a channel layer 47 formed by selective ion implantation and annealing on the surface of a semi-insulating GaAs substrate 41. Source electrode 45, drain electrode 42
Is provided to form a unit cell of GaAs FET. Each unit cell has a gate bonding pad 47 and a drain bonding pad 48. Further, a via hole 46 is provided below the source electrode 45, and the hole is filled with gold to form a so-called PHS (Plated Heat Sink) via hole structure. Usually, 6 to 12 such unit cells are arranged in parallel in the lateral direction, and the lateral width of the transistor chip reaches 5 mm or more.

[Problems to be Solved by the Invention]

When a large number of unit cells are arranged in parallel, the chip width becomes 5 mm or more as described above.At this time, the strip conductor width of the microstrip line with a characteristic impedance of 50 Ω provided on a 0.635 mm alumina substrate is 0.635 mm. Is.

FIG. 4 shows a transistor chip and a microstrip line provided on an alumina substrate.
Reference numerals 51, 53, 55 and 57 are gate bonding pads of each unit cell of the transistor chip, and 48, 50, 52, 54, 56 and 58 are drain bonding pads of each unit cell of the transistor chip.

On the input side, efficient amplification cannot be performed unless the signal output from the tip portion 62 of the microstrip line 59 is fed to all unit cells in phase. In the figure, for convenience of explanation, concentric circles 63 and 64 having the tip portion 62 as a signal source are drawn. When the gate bonding pads 51, 53 located on the concentric circle 63 are attempted to be excited in phase, the gate bond pads 47, 4
9,55,57 are not in-phase excited, and when trying to in-phase excite the gate pads 47,57 located on the concentric circle 64, the gate pads 49,51,53,55 are not in-phase excited. Therefore,
In-phase power supply cannot be applied to all unit cells.

The same applies to power combination on the output side. In the figure, concentric circles 65 and 66 centering on the tip 61 of the microstrip line 60 are shown, but the output signals coming out from the drain bonding pads 52 and 54 located on the concentric circle 65 are transferred to the tip of the microstrip line 60. When attempting to synthesize in-phase with the part 61, the drain bonding pads 48, 50,
The output signals from 56 and 58 cannot be combined in phase. Also, the drain bonding pads 48,5 located on the concentric circle 66
If the output signal from 8 is combined in phase with the tip 61 of the microstrip line 60, the output signals from the drain bonding pads 50, 52, 54, 56 cannot be combined in phase.

Therefore, conventionally, as shown in FIG. 5, gate-bonding pads 47, 49, 51 and 53, 55, 57 on the input side are relay electrodes 81, which also function as capacitors formed on dielectric substrates 80, 82, respectively. Bonding wires 90,91,92 and 93,9 to 83
4, 95 are used for connection, and the relay electrodes 81, 83 and the microstrip line 89 are connected using bonding wires 73, 74. This is a so-called tree-like structure.

Output side drain bonding pad 48,50,52,54,56,5
The same applies to 8 as well, and the microstrip line 60 is provided via relay electrodes 76 and 79 provided on the dielectric substrates 75 and 77.
Bonding wires 96,97,98,99,100,101 and 71,72
Are connected using.

However, even in the configuration shown in FIG. 5, complete in-phase excitation has not been realized, and especially when the frequency is 20 GHz or more, the unevenness of the phase becomes remarkable, and efficient power combining cannot be performed, which is a problem.

It is an object of the present invention to provide a microwave millimeter wave high output transistor which eliminates the above drawbacks, facilitates impedance matching, and enables efficient power combination.

[Means for Solving the Problems]

The present invention relates to a microwave millimeter-wave transistor in which single elements are arranged in a row in a row to achieve high output, and an input transmission line configured by sequentially connecting input terminals of all unit elements and an input transmission line of all unit elements. Make sure that the output transmission line configured by connecting the output terminals in sequence and the output transmission line have a characteristic impedance of 50Ω or less and that the output transmission line phase constant and the input transmission line phase constant are equal. It is characterized in that it is provided with a capacitor distributively arranged between a line conductor and a ground plane, and four bonding pads provided one at each end of the input transmission line and at each end of the output transmission line. There is.

[Action]

In the present invention, a traveling wave and a backward wave are excited in the input transmission line of the transistor chip, and power amplification is performed by using both the traveling wave and the backward wave correspondingly generated in the output transmission line, and Since the characteristic impedance of is lower than 50Ω, high output can be obtained.

Further, since the traveling wave and the backward wave are used, it is not necessary to make each drain bonding pad and each gate bonding pad in phase with each other, so that mounting in the microwave band and the millimeter wave band becomes extremely easy.

〔Example〕

FIG. 1 shows a microwave millimeter wave high power transistor according to an embodiment of the present invention.

This microwave millimeter wave high power transistor is semi-insulating
On the n-type channel layer 11 formed on the GaAs substrate 1 by selective ion implantation and annealing, the Schottky gate electrode 6 made of A1, the drain electrode 8 made of AuGeNi, the AuGeNi.
The source electrode 7 made of is periodically formed. A via hole 9 filled with gold is provided below the source electrode 7 to form a ground plane. In addition, the drain electrode 8
The additional capacitor 10 is periodically provided between the source electrode 7 and the source electrode 7.

The input transmission line is composed of the input bonding pad 2 and the input bonding pad 3. The characteristic impedance Z _0i of this input transmission line is calculated using the capacitance C _gs per unit length of the input transmission line (mainly the input capacitance of the FET) and the inductance L _g per unit length, And the phase constant β _i is Is expressed as

On the other hand, the output transmission line is formed from the output bonding pad 4 to the output bonding pad 5. The capacitance per unit length of this output transmission line is C _ds + C _D (C
_{ds is} the output capacitance of the FET, C _{D is} the capacitance of the additional capacitor, and L _D is the inductance per unit length, the characteristic impedance Z _0o and the phase constant β _o of the output transmission line are Is expressed as

In the present invention, β _i = β _o , so that from equations (2) and (4), Becomes From equations (3) and (5), Becomes Z _0o ＝ 10Ω, C _gs = 1pF / mm, L _g ＝ 2.5nH, Cds ＝ 0.3pF
If it is / cm, then C _D = 4.7pF / mm (7) L _D = 0.5nH / mm (8).

FIG. 2 is a circuit configuration diagram when the microwave millimeter wave high output transistor shown in FIG. 1 is actually operated.
In FIG. 2, a microstrip line 20 connected to a signal source is branched into two quarter wavelength lines 18 and 19 and serves as an input terminal of a Wilkinson type power distributor. 26 is a ballast resistor. One of the two branched signals is input to the first input bonding pad 2 of the high output transistor chip via the bonding wire 30 via the microstrip line 16. The other of the two branched signals is input to the second input bonding pad 3 via the microstrip line 17 and the bonding wire 27.

The output signal is taken out from the output bonding pads 4 and 5 through the bonding wires 29 and 28, and the ballast resistors 31 and 1/4 through the microstrip lines 22 and 21, respectively.
It is combined by the Wilkinson type power combiner composed of the wavelength lines 23 and 24 and output from the microstrip line 25.

In the microwave millimeter wave high power transistor of the present embodiment, the signal input to the input boarding pad 2 propagates on the input transmission line toward the input bonding pad 3 at the phase velocity β _i while the signal is output to the output transmission line. The current generated above travels from the output bonding pad 4 toward the output bonding pad 5 at a phase velocity β _o (= β _i ) and increases its amplitude. On the other hand, the input bonding pad 3
The signal input to the input signal goes backward to the input bonding pad 2 at the phase velocity β _i (= β _o ). At this time, the current generated in the output transmission line travels backward from the output bonding pad 5 toward the output bonding pad 4 and increases its amplitude.

Drain breakdown voltage V _{BD of the} transistor is 20V, Z _0o = 10Ω
Then, the maximum power P _out output from the two output bonding pads 4,5 is Becomes

In this embodiment, a GaAs FET is used, but the amplification element is GaAsF.
Not limited to ET, InPFET, HBT, etc. may be used.

〔The invention's effect〕

As described above, according to the present invention, it is not necessary to satisfy the in-phase excitation condition when designing and manufacturing the matching circuit, and the effect is great especially in the microwave millimeter wave region where the wavelength is short and it is difficult to realize the in-phase excitation circuit.

[Brief description of drawings]

FIG. 1 is a diagram showing a high output transistor according to an embodiment of the present invention, FIG. 2 is a diagram for explaining an operating method thereof, FIG. 3 is a diagram showing a conventional high output transistor, FIG. FIG. 5 is a diagram for explaining an operating method of the conventional high output transistor of FIG. 1,41 …… Semi-insulating GaAs substrate 2,3 …… Input bonding pad 4,5 …… Output bonding pad 6,43 …… Gate electrode 8,42 …… Drain electrode 7,45 …… Source electrode 9,46 …… Via hole 10 …… Additional capacitor 18,19,20,16,17,21,22,24,23,25,59,60 …… Microstrip line 27,28,29,30,71,72,73 , 74,90,91,92,94,95,96,97,98,9
9,100,101 …… Bonding wire 76,79,81,83 …… Intermediate electrode

Claims (1)

[Claims] 1. In a microwave millimeter-wave transistor in which single elements are arranged in a horizontal example to achieve high output, an input transmission line formed by sequentially connecting input terminals of all unit elements, and all unit elements The output transmission line configured by sequentially connecting the output terminals of the output transmission line and the output transmission line so that the characteristic impedance of the output transmission line is 50Ω or less and the phase constant of the output transmission line is equal to the phase constant of the input transmission line. And a bonding pad disposed distributively between the line conductor and the ground plane, and four bonding pads provided one at each end of the input transmission line and at each end of the output transmission line. Microwave millimeter wave high power transistor.