JP2007173299A - Gunn diode oscillator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gunn diode oscillator which is reduced in the variation of frequency caused by assembling. <P>SOLUTION: A flip-chip type gunn diode is connected to and mounted on the surface of a semi-insulating or insulating plate substrate. The Gunn diode having such the structure is provided with an anode electrode at the center and cathode electrodes on both sides. The anode electrode is connected with a surface grounding electrode. One of the cathode electrodes is connected with a signal electrode, and the other is connected with an open stub. Due to such the structure, the surface grounding electrode does not function as an open stub, and the variation of an oscillation frequency can be suppressed. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an oscillator using a microwave or millimeter wave Gunn diode, and more particularly to a surface-mounted Gunn diode oscillator in which an improvement in oscillation output and an improvement in temperature characteristics are facilitated.

  FIG. 4 shows a flip-chip type Gunn diode 20 used for a microwave or millimeter wave oscillator. 4A is a plan view, and FIG. 4B is a cross-sectional view taken along the line AA in FIG. 4A. A first semiconductor layer 22 made of high-concentration n-type GaAs, an active layer 23 made of low-concentration n-type GaAs, and a high-concentration n-type GaAs on a semiconductor substrate 21 made of high-concentration n-type GaAs by MBE or MOCVD. In order to reduce the area of the electron travel space, the contact layer 24 is made of a mesa structure. Reference numeral 25 denotes an insulating region, 26 denotes a cathode electrode, 27 denotes an anode electrode, 28 denotes a cathode bump with conductive protrusions, and 29 denotes an anode bump with conductive protrusions. The insulating region 25 is formed in a cylindrical shape by implanting boron ions from the surface of the contact layer 24 to the boundary between the active layer 23 and the first semiconductor layer 22, and the cathode electrode 26 is separated from the anode electrode 27. A functional part of a Gunn diode is formed by the inner first semiconductor layer 22, the active layer 23, and the contact layer 24 surrounded by. In FIG. 4, six cylindrical portions are formed by the insulating regions 25, and Gunn diode function portions are formed below the six cathode electrodes 26. The cathode bumps 28 are respectively formed on the upper surfaces of the six cathode electrodes 26. The anode bumps 29 are formed on a part of the upper surface of the anode electrode 27 and 3 on one side so as to sandwich a group of the cathode bumps 28 from both sides. A total of six pieces are formed.

FIG. 5 is an enlarged cross-sectional view of a Gunn diode connection portion of a Gunn diode oscillator configured by mounting the Gunn diode 20 of FIG. 4 on an oscillation circuit 30 composed of a microstrip line. FIG. 6 is an explanatory diagram of the Gunn diode oscillator 10, FIG. 6 (a) is an overall perspective view of the Gunn diode oscillator 10, and FIG. 6 (b) is a perspective view showing its hidden line. As shown in FIGS. 5 and 6, the oscillation circuit 30 includes a signal electrode 32 and two surface ground electrodes 33 formed on the surface of a semi-insulating flat substrate 31 so as to sandwich the signal electrode 32 from both sides. The back surface ground electrode 34 is formed on the back surface. The front surface ground electrode 33 and the back surface ground electrode 34 are electrically connected by a columnar via hole 35. The signal electrode 32 is formed with a bias electrode 32A for supplying power to the Gunn diode 20, an open stub 32B constituting a resonator, and an output part 32C for extracting oscillation output. The Gunn diode 20 is mounted such that the central cathode bump 28 is bonded to the signal electrode 32 and the anode bumps 29 on both sides are bonded to the surface ground electrodes 33 on both sides. The heat of the functional part of the Gunn diode 20 is radiated through the heat radiation base 36. 6A and 6B, the heat dissipation base 36 is not shown. This type of Gunn diode oscillator is disclosed in Patent Document 1.
JP 2003-152246 A

  As described above, when the flip-chip type Gunn diode is mounted on the oscillation circuit and the Gunn diode oscillator is configured, the surface ground electrode 33 and the back surface ground electrode 34 are electrically connected by the via hole 35. Part of it functions as a short stub. That is, there is a problem that the interval between the two via holes 35 contributes to the determination of the oscillation frequency, and the variation in the interval between the via holes causes the variation in the oscillation frequency. In the case of a voltage-controlled Gunn diode oscillator that uses a varactor diode to control the oscillation frequency, there is a similar problem.

  An object of the present invention is to provide a Gunn diode oscillator that solves the above-described problems and has less variation in oscillation frequency caused by assembly.

  In order to achieve the above object, the invention according to claim 1 of the present application is a Gunn diode oscillator in which a flip chip type Gunn diode is connected and mounted on a semi-insulating or insulating flat substrate surface. The first electrode of either the anode or the cathode electrode is arranged, the second electrode of either the cathode or the anode electrode is arranged on both sides of the first electrode, the flat plate substrate has a signal electrode on the surface, A bias electrode for a Gunn diode connected to the signal electrode, a front surface ground electrode, and a first open stub; a rear surface ground electrode on the rear surface; and the front surface ground electrode and the rear surface through a via hole penetrating from the front surface to the rear surface A ground electrode is connected; the first electrode is connected to the surface ground electrode; one of the second electrodes is connected to the signal electrode; It is characterized in that the other electrode of the electrode is connected to the first open stub.

  According to a second aspect of the present invention, in the Gunn diode oscillator according to the first aspect, the flat substrate further includes a second oven stub and a varactor diode bias electrode connected to the second open stub. One electrode of a varactor diode is connected to the first open stub to which the other electrode of the second electrode of the diode is connected, and the other electrode of the varactor diode is connected to the second open stub. It is what.

  According to the present invention, since the first electrode of the Gunn diode is connected to the surface ground electrode provided immediately above the via hole, the surface ground electrode does not function as a short stub and the oscillation frequency varies. It is possible to obtain a Gunn diode oscillator or a voltage controlled Gunn diode oscillator with a small amount.

  In addition, since the functional part which is the heat generating part of the Gunn diode is arranged immediately above the via hole, the heat generated in the functional part is radiated to the heat radiation base via the via hole, and a high heat radiation effect is obtained. . Along with this, the oscillation efficiency of the Gunn diode oscillator is also improved.

  Hereinafter, the present invention will be described in detail according to examples.

  First, the first embodiment will be described. The flip-chip type Gunn diode 20A used in the present embodiment is similar to the Gunn diode 20 described with reference to FIG. 4 on the semiconductor substrate 21 made of high-concentration n-type GaAs by the MBE method or the MOCVD method. The first semiconductor layer 22 made of, an active layer 23 made of low-concentration n-type GaAs, and a contact layer 24 made of high-concentration n-type GaAs are sequentially stacked. In this structure, boron ions are implanted to the boundary between the active layer 23 and the first semiconductor layer 22 by the insulating region 25 formed in a cylindrical shape.

  Here, the Gunn diode 20A of this embodiment has a structure in which the cathode electrode 26 and the cathode bump 28 are replaced with the anode electrode 27 and the anode bump 29, as compared with the Gunn diode 20 shown in FIG. That is, the anode bumps 29 are formed on the upper surfaces of the six anode electrodes 27, respectively, and the cathode bumps 28 are formed on a part of the upper surface of the cathode electrode 26 and three on one side so as to sandwich a group of anode bumps 29 from both sides. Six pieces are formed in total.

  FIG. 1 is an enlarged cross-sectional view of a connecting portion of a Gunn diode 20A of a Gunn diode oscillator 10A according to the present invention in which the Gunn diode 20A is mounted on an oscillation circuit 30A composed of a microstrip line. FIG. 2 is an explanatory view of the Gunn diode oscillator, FIG. 2 (a) is an overall perspective view of the Gunn diode oscillator 10A, and FIG. 2 (b) is a perspective view showing its hidden line. The same components as those in FIG. 4 are denoted by the same reference numerals.

Oscillation circuit 30A has a good semi-insulation with a specific resistance of 10 ⁶ Ω · cm or more and a thermal conductivity of 140 W / mK or more, such as aluminum nitride (AlN), silicon (Si), silicon carbide (SiC), and diamond. A flat substrate 31, a signal electrode 32, a bias electrode 32 A for supplying power to the Gunn diode 20 A connected to the signal electrode 32, and an output for extracting oscillation output An open stub 32D (corresponding to the first open stub) independent of the part 32C and the signal electrode 32 and a surface ground electrode 33A are formed. A back surface ground electrode 34 is formed on the back surface. The surface ground electrode 33A and the back surface ground electrode 34 are electrically connected by a columnar via hole 35A. As shown in FIGS. 1 and 2, in this embodiment, the structure of the signal line 32, the open stub 32D, and the surface ground electrode 33A is different from the structure of the conventional example shown in FIG. 2A and 2B, the heat dissipation base 36 is not shown.

  The Gunn diode 20A has an anode bump 29 (corresponding to the first electrode) disposed in the center thereof connected to the surface ground electrode 33A, and one of the cathode bumps 28 (corresponding to the second electrode) connected to the signal electrode 32. The other of the cathode bumps 28 is connected to the open stub 32D.

  With such a structure, when the back ground electrode 34 is set to a fixed potential and a DC voltage is applied to the bias electrode 32A, the Gunn diode 20A oscillates.

  In the Gunn diode oscillator 10A of the present embodiment, the anode bump 29 of the Gunn diode 20A is connected to the surface ground electrode 33A, so that the surface ground electrode 33A does not function as a short stub. There is no frequency variation and good characteristics can be obtained.

  In addition, since the functional part defined by the insulating region 25 which is a heat generating part in the Gunn diode 20A is disposed immediately above the via hole 35A, the generated heat passes through the anode bump 29 and the via hole 35A and is connected to the back surface ground electrode 34. Is effectively radiated to the heat dissipation base 36 functioning as a heat sink to which the heat sink adheres. As the heat dissipation effect is increased in this way, the oscillation efficiency of the Gunn diode oscillator is also improved.

  FIG. 3 is an explanatory diagram of the voltage-controlled Gunn diode oscillator of the second embodiment. FIG. 3 (a) is an overall perspective view of an oscillation circuit 11 composed of a microstrip line, and FIG. It is the perspective view which displayed the hidden line. The same components as those in FIGS. 2 and 4 are denoted by the same reference numerals.

  In the present embodiment, an open stub 32E (second open stub) is provided at a position distant from the extended line of the open stub 32D (first open stub), and the electrodes of the varactor diode 40 are provided on the open stub 32D and the open stub 32E, respectively. Connected and mounted.

  In the present embodiment, a power supply voltage (DC voltage) is applied to the Gunn diode 20A via the bias electrode 32A, and the varactor diode 40 is connected via the bias electrode 32F (corresponding to the bias electrode for varactor diode) connected to the open stub 32E. By applying a bias to, the oscillation frequency of the Gunn diode oscillator 11 output from the output unit 32C can be modulated and used as a voltage controlled oscillator.

  In this way, even with a voltage-controlled Gunn diode oscillator, a Gunn diode oscillator with little variation in oscillation frequency and excellent heat dissipation efficiency and oscillation efficiency is obtained, as with the Gunn diode oscillator of the first embodiment shown in FIG. Obtainable.

  In the above description, the cathode electrode 26 and the cathode bump 28, and the anode electrode 27 and the anode bump 29 may be reversed depending on the polarity of the bias voltage to be applied.

It is a partial enlarged view of the Gunn diode oscillator of the present invention. It is explanatory drawing of the Gunn diode oscillator of this invention. It is a partial enlarged view of the voltage controlled Gunn diode oscillator of the present invention. It is explanatory drawing of a Gunn diode. It is a partial enlarged view of a Gunn diode oscillator. It is explanatory drawing of a Gunn diode oscillator.

Explanation of symbols

10, 10A: Gunn diode oscillator, 11: Voltage controlled Gunn diode oscillator, 20: Gunn diode, 21: Semiconductor substrate, 22: First semiconductor layer, 23: Active layer, 24: Contact layer, 25: Insulating region, 26 : Cathode electrode, 27: anode electrode, 28: cathode bump, 29: anode bump, 30: oscillation circuit, 31: flat substrate, 32: signal electrode, 32A: bias electrode, 32B: open stub, 32C: output unit, 32D : Open stub, 32E: Open stub, 32F: Bias electrode, 33: Front surface ground electrode, 34: Back surface ground electrode, 35: Via hole, 36: Heat radiation base, 40: Varactor diode

Claims (2)

In a Gunn diode oscillator in which a flip chip type Gunn diode is connected and mounted on a semi-insulating or insulating flat substrate surface,
The Gunn diode has a first electrode of either an anode or a cathode electrode arranged in the center, and a second electrode of either the cathode or the anode electrode is arranged on both sides of the first electrode,
The flat substrate includes a signal electrode on the front surface, a bias electrode for a Gunn diode connected to the signal electrode, a front surface ground electrode, and a first open stub. The front surface ground electrode and the back surface ground electrode are connected through a via hole.
The first electrode is connected to the surface ground electrode, one electrode of the second electrode is connected to the signal electrode, and the other electrode of the second electrode is connected to the first open stub. A characteristic Gunn diode oscillator. The Gunn diode oscillator according to claim 1, wherein
The flat substrate further comprises a second oven stub and a varactor diode bias electrode connected to the second open stub,
One electrode of a varactor diode is connected to the first open stub to which the other electrode of the second electrode of the Gunn diode is connected, and the other electrode of the varactor diode is connected to the second open stub. Gunn diode oscillator.

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