JP6724695B2 - Semiconductor device, power supply device, amplifier, heating device, exhaust gas purification device, automobile and information system - Google Patents

Description

The present invention relates to a semiconductor device, a power supply device, an amplifier, a heating device, an exhaust emission control device, an automobile and an information system.

Nitride semiconductors, which have characteristics such as high saturation electron velocity and wide band gap, are being studied for application to semiconductor devices with high breakdown voltage and high output. For example, the band gap of GaN, which is a nitride semiconductor, is 3.4 eV, which is larger than the band gaps of Si (1.1 eV) and GaAs (1.4 eV), and has a high breakdown electric field strength. Therefore, a nitride semiconductor such as GaN is very promising as a material for a semiconductor device for a power supply that obtains high voltage operation and high output.

As a semiconductor device using a nitride semiconductor, many reports have been made on a field effect transistor, particularly a high electron mobility transistor (HEMT). For example, in a GaN-based HEMT (GaN-HEMT), attention is paid to an HEMT composed of AlGaN/GaN using GaN as an electron transit layer and AlGaN as an electron supply layer. In a HEMT made of AlGaN/GaN, strain due to the lattice constant difference between GaN and AlGaN occurs in AlGaN. Due to the piezoelectric polarization generated thereby and the spontaneous polarization difference of AlGaN, a high concentration of 2DEG (Two-Dimensional Electron Gas) can be obtained. Therefore, it is expected as a highly efficient switching element and a high withstand voltage power device for electric vehicles.

JP, 2002-359256, A Japanese Patent Laid-Open No. 5-110106 Japanese Patent Laid-Open No. 11-260834

By the way, when the above GaN-HEMT is used for electric power, a high voltage is applied and a large current flows, so that the temperature of the GaN-HEMT becomes high. As described above, when the temperature of the GaN-HEMT increases, the characteristics of the GaN-HEMT change, the on-current decreases, and the semiconductor device may be destroyed by heat, which causes the reliability of the semiconductor device to deteriorate. ..

Therefore, even if heat is generated in the semiconductor device, heat is satisfactorily radiated, and a highly reliable semiconductor device is demanded.

According to one aspect of this embodiment, a semiconductor layer formed of a semiconductor on a substrate, a gate electrode, a source electrode, and a drain electrode formed on the semiconductor layer, the semiconductor layer, and a gate electrode. An insulating film formed on the source electrode and the drain electrode, a heat dissipation part formed on the insulating film, a film formed of ceramic on the insulating film and the heat dissipation part, and A heat radiating plate formed of metal or ceramics on the upper side, and the heat radiating portion is formed such that the width on the side distant from the side close to the semiconductor is wider.

According to the disclosed semiconductor device, even if heat is generated in the semiconductor device, heat is radiated favorably, so that the reliability of the semiconductor device can be improved.

Top view of semiconductor device Cross section of semiconductor device The top view of the semiconductor device in 1st Embodiment Sectional drawing of the semiconductor device in 1st Embodiment Process drawing (1) of the manufacturing method of the semiconductor device in 1st Embodiment Process drawing of the manufacturing method of the semiconductor device in the first embodiment (2) Process drawing of the manufacturing method of the semiconductor device in the first embodiment (3) Process drawing of the manufacturing method of the semiconductor device in the first embodiment (4) Process drawing of the manufacturing method of the semiconductor device in the first embodiment (5) Process drawing (6) of the manufacturing method of the semiconductor device in 1st Embodiment Sectional drawing of the modification 1 of the semiconductor device in 1st Embodiment. Sectional drawing of the modification 2 of the semiconductor device in 1st Embodiment. Explanatory view of a discretely packaged semiconductor device according to a second embodiment. Circuit diagram of the power supply device in the second embodiment Structural diagram of the high-frequency amplifier according to the second embodiment Structural drawing of the microwave heating apparatus in the third embodiment Structural diagram of the exhaust emission control device in the fourth embodiment Explanatory drawing of the vehicle in 4th Embodiment Explanatory drawing of the information system in 4th Embodiment

A mode for carrying out the invention will be described below. The same members and the like are designated by the same reference numerals and the description thereof will be omitted.

[First Embodiment]
First, heat generation that occurs when a GaN-HEMT, which is a semiconductor device using a nitride semiconductor, is operated will be described with reference to FIGS. 1 and 2. FIG. 1 is a plan view of the semiconductor device when viewed in plan, and FIG. 2 is a cross-sectional view taken along the alternate long and short dash line 1A-1B in FIG. In the present application, “plan view” refers to a field of view of a semiconductor device in a normal direction to a surface on which a gate electrode, a source electrode, and a drain electrode, which will be described later, are formed. Further, in FIG. 1, the insulating film 940 is omitted for convenience.

As shown in FIG. 2, this semiconductor device is formed by laminating a buffer layer 911 formed of a nitride semiconductor, an electron transit layer 921, and an electron supply layer 922 on a substrate 910. The substrate 910 is formed of a semiconductor substrate such as SiC, and the buffer layer 911 is formed of AlN, AlGaN, GaN or the like. The electron transit layer 921 is made of GaN or the like, and the electron supply layer 922 is made of AlGaN or the like. As a result, 2DEG 921a is generated in the electron transit layer 921 in the vicinity of the interface between the electron transit layer 921 and the electron supply layer 922.

Further, on the electron supply layer 922, a gate electrode 931, a source electrode 932, and a drain electrode 933 having a comb-tooth-shaped electrode structure are formed. Specifically, as shown in FIG. 1, the comb teeth of the drain electrode 933 are inserted between the comb teeth of the source electrode 932, and between the comb teeth of the source electrode 932 and the comb teeth of the drain electrode 933. At the bottom, comb teeth of the gate electrode 931 are formed. Further, as shown in FIG. 2, an insulating film 940 serving as a protective film covering these is formed on the gate electrode 931, the source electrode 932, the drain electrode 933, and the electron supply layer 922.

By the way, when the semiconductor device having the structure shown in FIGS. 1 and 2 is operated, heat is generated, and in particular, the electron transit layer 921 and the electron supply layer in the region immediately below the drain electrode 933 side of the gate electrode 931 surrounded by the broken line. The temperature at the portion at 922 increases. Therefore, a heat sink (not shown) is provided by metal on the back surface side of the substrate 910 opposite to the front surface side on which the gate electrode 931, the source electrode 932, and the drain electrode 933 are formed, and the heat is dissipated from the heat sink plate. There is a case. By providing such a heat dissipation plate, the heat generated between the electron transit layer 921 and the electron supply layer 922 in the region immediately below the gate electrode 931 on the drain electrode 933 side is generated by the electron transit layer 921, the buffer layer 911, It flows to the heat sink through the substrate 910, and the heat is dissipated from the heat sink.

However, although the substrate 910 is made of SiC or the like, it has a large thickness of 50 μm to 300 μm, and thus the distance from the electron transit layer 921 and the electron supply layer 922 where heat is generated to the heat dissipation plate is long. The heat is not dissipated efficiently. For this reason, heat is accumulated between the electron transit layer 921 and the electron supply layer 922, and the temperature becomes high, leading to a decrease in reliability of the semiconductor device. Particularly, when a high voltage is applied and a large current flows, the heat generation in the electron transit layer 921 and the electron supply layer 922 is remarkable and the temperature tends to be high. Therefore, even if heat is generated in the semiconductor device, heat is satisfactorily radiated, and there is a demand for a highly reliable semiconductor device that does not change its characteristics.

(Semiconductor device)
Next, the semiconductor device according to the first embodiment will be described with reference to FIGS. 3 and 4. FIG. 3 is a plan view of the semiconductor device according to the present embodiment when viewed in plan, and FIG. 4 is a cross-sectional view taken along alternate long and short dash line 3A-3B in FIG. Note that, in FIG. 3, the insulating film 40 and the like are omitted for convenience.

As shown in FIG. 4, this semiconductor device is formed by laminating a buffer layer 11, which is made of a nitride semiconductor, an electron transit layer 21, and an electron supply layer 22, on a substrate 10. The substrate 10 is formed of a semiconductor substrate such as SiC, and the buffer layer 11 is formed of AlN, AlGaN, GaN or the like. The electron transit layer 21 is made of GaN or the like, and the electron supply layer 22 is made of AlGaN or the like. As a result, 2DEG 21a is generated in the electron transit layer 21 in the vicinity of the interface between the electron transit layer 21 and the electron supply layer 22.

Further, as shown in FIG. 3, a gate electrode 31, a source electrode 32, and a drain electrode 33 having a comb-like electrode structure are formed on the electron supply layer 22. Specifically, the comb teeth of the drain electrode 33 are inserted between the comb teeth of the source electrode 32, and the comb teeth of the gate electrode 31 are inserted between the comb teeth of the source electrode 32 and the drain electrode 33. Are formed. Further, as shown in FIG. 4, an insulating film 40 serving as a protective film is formed on the gate electrode 31, the source electrode 32, the drain electrode 33, and the electron supply layer 22 to cover them.

A heat dissipation portion 50 is formed above the gate electrode 31 on the drain electrode 33 side with an insulating film 40 interposed therebetween, and a heat dissipation plate 60 in contact with the heat dissipation portion 50 is formed on the insulating film 40 and the heat dissipation portion 50. ing. Specifically, the heat dissipation part 50 is embedded in the insulating film 40, and the heat dissipation part 50 is formed on the insulating film 40. The heat dissipation part 50 is formed of metal, ceramics having a low thermal conductivity, carbon nanotube, or the like. When the heat dissipation part 50 is formed of a metal, the metal forming the heat dissipation part 50 is preferably Au, Cu, Al or the like having high thermal conductivity. The heat dissipation plate 60 is made of metal such as Au, Cu, Al or ceramics such as SiC. The formed insulating film 40 has a thickness of about 4.1 μm. Further, a source wiring part 72 connected to the heat dissipation plate 60 is formed on the source electrode 32, and the source electrode 32 and the heat dissipation plate 60 are electrically connected via the source wiring part 72. .. Therefore, the source wiring portion 72 penetrates the insulating film 40 and electrically connects the source electrode 32 and the heat dissipation plate 60.

The heat dissipation portion 50 is formed above the gate electrode 31 on the drain electrode 33 side and on the gate electrode 31 side of the electron supply layer 22 between the gate electrode 31 and the drain electrode 33 via the insulating film 40. On the drain electrode 33 side of the gate electrode 31, the thickness t1 of the insulating film 40 between the gate electrode 31 and the heat dissipation part 50 is formed to be about 100 nm. Further, on the gate electrode 31 side between the gate electrode 31 and the drain electrode 33, the thickness t2 of the insulating film 40 between the electron supply layer 22 and the heat dissipation portion 50 is formed to be about 100 nm.

Therefore, even if heat is generated between the electron transit layer 21 and the electron supply layer 22 in the region immediately below the drain electrode 33 side of the gate electrode 31, the insulating film 40 having a thickness of about 100 nm from the electron supply layer 22 and the gate electrode 31. Heat flows to the heat radiating portion 50 via the heat radiation plate 50 and is radiated from the heat radiation plate 60. Therefore, since the distance to the heat dissipation portion 50 formed of a metal or the like having a high thermal conductivity is short, the heat generated between the electron transit layer 21 and the electron supply layer 22 passes through the heat dissipation portion 50 and the heat dissipation plate. The heat is transmitted to the heat sink 60 and is smoothly radiated from the heat sink 60.

Further, in the present embodiment, the heat dissipation portion 50 is formed so that the width thereof becomes wider as the distance from the electron supply layer 22 increases. Specifically, the heat dissipation portion 50 is formed such that the width on the side closer to the electron supply layer 22 is narrower and the width on the side closer to the heat dissipation plate 60 separated from the electron supply layer 22 is wider. As the distance from the electron supply layer 22 is increased, the width of the heat dissipation portion 50 is increased, so that the heat generated between the electron transit layer 21 and the electron supply layer 22 can be smoothly transferred to the heat dissipation plate 60. .. Therefore, the heat dissipation part 50 may be formed such that the area in a plan view is narrower on the side closer to the electron supply layer 22 and wider on the side closer to the heat dissipation plate 60 away from the electron supply layer 22.

Therefore, the semiconductor device in this embodiment can be prevented from being heated to a high temperature, characteristics can be prevented from being changed, and reliability of the semiconductor device can be improved. According to the inventor's knowledge, the semiconductor device having the structure shown in FIGS. 3 and 4 has a thermal resistance reduced by about 30% as compared with the semiconductor device having the structure shown in FIGS. 1 and 2. Inferred.

(Method of manufacturing semiconductor device)
Next, a method of manufacturing the semiconductor device according to the present embodiment will be described with reference to FIGS. The nitride semiconductor formed on the substrate 10 is formed by epitaxial growth by MOVPE (Metal-Organic Vapor Phase Epitaxy). When growing a nitride semiconductor by MOVPE, TMA (trimethylaluminum) is used as a source gas of Al, TMG (trimethylgallium) is used as a source gas of Ga, and NH ₃ is used as a source gas of N. (Ammonia) is used.

First, as shown in FIG. 5A, a nucleation layer, a buffer layer 11, an electron transit layer 21, and an electron supply layer 22 (not shown) are sequentially laminated on the substrate 10 by MOVPE. A SiC substrate is used as the substrate 10, and the nucleation layer (not shown) is formed of an AlN film having a film thickness of 1 nm to 300 nm, for example, 160 nm. The buffer layer 11 is formed of an AlGaN film having a film thickness of 1 nm to 1000 nm, for example, 600 nm. The electron transit layer 21 is formed of an i-GaN film having a thickness of about 3.0 μm. The electron supply layer 22 is formed of i-AlGaN having a film thickness of about 20 nm. As a result, 2DEG 21a is generated in the electron transit layer 21 near the interface between the electron transit layer 21 and the electron supply layer 22. Although not shown, a spacer layer may be formed between the electron transit layer 21 and the electron supply layer 22 by i-AlGaN having a thickness of about 5 nm, and the spacer layer may be formed on the electron supply layer 22. The cap layer may be formed of n-GaN having a film thickness of 10 nm. The cap layer is doped with Si as an n-type impurity element so that the impurity concentration becomes 5×10 ¹⁸ cm ⁻³ . The electron supply layer 22 may be made of InAlN. As the substrate 10, a substrate of sapphire, Si, GaAs, or the like other than SiC can be used, and the conductivity of the substrate may be semi-insulating or conductive. Good.

After that, although not shown, an element isolation region for isolating elements is formed. Specifically, a photoresist is applied on the electron supply layer 22, and exposure and development are performed by an exposure device to form a resist pattern having an opening in a region where an element isolation region is formed. Then, element isolation regions are formed by implanting argon (Ar) ions into the nitride semiconductor layer in the regions where the resist pattern is not formed. The element isolation region may be formed by removing a part of the nitride semiconductor layer in the region where the resist pattern is not formed by dry etching such as RIE (Reactive Ion Etching). After forming the element isolation region, the resist pattern is removed with an organic solvent or the like.

Next, as shown in FIG. 5B, the source electrode 32 and the drain electrode 33 are formed on the electron supply layer 22. Specifically, a photoresist (not shown) having an opening in a region where the source electrode 32 and the drain electrode 33 are formed by applying a photoresist on the electron supply layer 22 and performing exposure and development with an exposure device. Form a pattern. After that, a Ti/Al metal laminated film is formed by vacuum vapor deposition and then immersed in an organic solvent or the like to remove the metal laminated film on the resist pattern together with the resist pattern by lift-off. As a result, the source electrode 32 and the drain electrode 33 are formed on the electron supply layer 22 by the remaining metal laminated film. The Ti/Al metal laminated film is a laminated film of a Ti film having a film thickness of 20 nm and an Al film having a film thickness of 200 nm, and is formed so that the Ti film is on the electron supply layer 22. Then, heat treatment is performed at a temperature of 400° C. to 1000° C., for example, 550° C. in a nitrogen atmosphere to establish ohmic contact in the source electrode 32 and the drain electrode 33.

Next, as shown in FIG. 6A, the first insulating film 41 is formed on the electron supply layer 22, the source electrode 32, and the drain electrode 33. Specifically, the first insulating film 41 is formed by forming a SiN film having a film thickness of 2 nm to 1000 nm by plasma CVD (plasma-enhanced chemical vapor deposition). In the present embodiment, the first insulating film 41 is formed by forming a SiN film having a film thickness of about 100 nm.

Next, as shown in FIG. 6B, the first insulating film 41 in the region where the gate electrode 31 is formed is removed and the opening 41a is formed. Specifically, a photoresist pattern (not shown) having an opening in a region where the gate electrode 31 is formed by applying a photoresist on the first insulating film 41 and performing exposure and development with an exposure device. To form. Then, the first insulating film 41 in the opening of the resist pattern is removed by dry etching such as RIE using a fluorine-based gas to expose the surface of the electron supply layer 22.

Next, as shown in FIG. 7A, the gate electrode 31 is formed on the electron supply layer 22. Specifically, a photoresist is applied on the first insulating film 41 and the electron supply layer 22, and exposure and development are performed by an exposure device, so that an opening is formed in a region where the gate electrode 31 is formed. The illustrated resist pattern is formed. After that, a metal laminated film of Ni/Au is formed by vacuum vapor deposition, and then the metal laminated film on the resist pattern is removed by lift-off together with the resist pattern by immersing it in an organic solvent or the like. As a result, the gate electrode 31 is formed on the electron supply layer 22 by the remaining metal laminated film. The Ni/Au metal laminated film is a laminated film of a Ni film having a film thickness of 30 nm and an Au film having a film thickness of 400 nm, and is formed so that the Ni film is on the electron supply layer 22.

Next, as shown in FIG. 7B, a second insulating film 42 is formed on the first insulating film 41 and the gate electrode 31. Specifically, the second insulating film 42 is formed by forming a SiN film having a film thickness of 2 nm to 10 μm by plasma CVD. In the present embodiment, the second insulating film 42 is formed by forming a SiN film having a film thickness of about 2 μm.

Next, as shown in FIG. 8A, by removing the first insulating film 41 and the second insulating film 42 in the region where the heat dissipation portion 50 and the source wiring portion 72 are formed, the openings 42a and 42b is formed. The method of forming the openings 42a and 42b in the second insulating film 42 is the same as the method of forming the opening 41a in the first insulating film 41 by forming a resist pattern and dry etching. In FIG. 8A, a step 42c is formed in the opening 42a, but when forming the opening 42a having such a step 42c, for example, formation of a resist pattern and dry etching are performed. It can be formed by performing twice.

In this embodiment, on the drain electrode 33 side of the gate electrode 31, the thickness t1 of the insulating film 40 on the gate electrode 31 is formed to be about 100 nm. On the gate electrode 31 side between the gate electrode 31 and the drain electrode 33, the insulating film 40 on the electron supply layer 22 is formed to have a thickness t2 of about 100 nm.

Next, as shown in FIG. 8B, the lower part 50a of the heat dissipation part 50 and the lower part 72a of the source wiring part 72 are formed by embedding the opening part 42a and the opening part 42b. Specifically, a seed layer (not shown) is formed in the openings 42a and 42b, and the openings 42a and 42b are filled with Au plating to fill the openings 42a and 42b. A lower portion 72a of 72 is formed.

Next, as shown in FIG. 9A, a third insulating film 43 is formed on the second insulating film 42, the lower portion 50a of the heat dissipation portion 50, and the lower portion 72a of the source wiring portion 72. Specifically, the third insulating film 43 is formed by forming a SiN film having a film thickness of 2 nm to 10 μm by plasma CVD. In the present embodiment, the third insulating film 43 is formed by forming a SiN film having a film thickness of about 2 μm.

Next, as shown in FIG. 9B, the openings 43a and 43b are formed by removing the third insulating film 43 in the region where the heat dissipation portion 50 and the source wiring portion 72 are formed. The method of forming the openings 43a and 43b in the third insulating film 43 is the same as the method of forming the opening 41a in the first insulating film 41 by forming a resist pattern and dry etching. As a result, the surface of the lower portion 50a of the heat dissipation portion 50 is exposed in the opening 43a of the third insulating film 43, and the surface of the lower portion 72a of the source wiring portion 72 is exposed in the opening 43b of the third insulating film 43. Let In the present embodiment, the opening 43a formed in the third insulating film 43 is wider than the lower part 50a of the heat dissipation part 50, and the opening 43b is smaller than the lower part 72a of the source wiring part 72. It is formed to have a wide width.

Next, as shown in FIG. 10A, the opening 43a and the opening 43b are embedded to form the upper portion 50b of the heat dissipation portion 50 and the upper portion 72b of the source wiring portion 72. Specifically, a seed layer (not shown) is formed in the openings 43a and 43b, and the openings 43a and 43b are buried by Au plating, so that the upper portion 50b of the heat dissipation portion 50 and the source wiring portion are formed. The upper portion 72b of 72 is formed. As a result, the lower portion 50a and the upper portion 50b form the heat dissipation portion 50, and the lower portion 72a and the upper portion 72b form the source wiring portion 72. In the formed heat dissipation portion 50, the width of the upper portion 50b is wider than that of the lower portion 50a, and in the source wiring portion 72, the width of the upper portion 72b is wider than that of the lower portion 72a. Further, the first insulating film 41, the second insulating film 42, and the third insulating film 43 form the insulating film 40.

Next, as shown in FIG. 10B, the heat dissipation plate 60 is formed on the insulating film 40, the heat dissipation part 50, and the source wiring part 72. Specifically, a seed layer is formed on the insulating film 40, the heat dissipation part 50, and the source wiring part 72, and Au is deposited by plating so that the film thickness is 10 μm.

Through the above steps, the semiconductor device in this embodiment can be manufactured.

(Modification 1)
In the semiconductor device shown in FIGS. 3 and 4, the heat dissipation plate 60 is formed of metal or the like, and the source electrode 32 and the heat dissipation plate 60 are electrically connected by the source wiring portion 72 formed of metal or the like. Therefore, the potential of the heat dissipation plate 60 is the same as the potential of the source electrode 32. Therefore, a parasitic capacitance is formed between the drain electrode 33 and the region of the heat dissipation plate 60 above the drain electrode 33.

Therefore, the present embodiment may be a semiconductor device having a structure in which the heat dissipation plate 60 is not formed above the drain electrode 33 as shown in FIG. That is, the heat dissipation plate 60 may be a semiconductor device having a structure which is formed above the gate electrode 31 and the source electrode 32 but not above the drain electrode 33. In the semiconductor device having such a structure, after the heat dissipation plate 60 is formed on the insulating film 40, the heat dissipation part 50, and the source wiring part 72, only the region above the drain electrode 33 of the heat dissipation plate 60 is wet-etched or dry-etched. It can be formed by removing with. Alternatively, a seed layer may be formed on the insulating film 40, the heat dissipation part 50, and the source wiring part 72 in a region except above the drain electrode 33, and Au may be deposited by plating.

(Modification 2)
Further, in the present embodiment, as shown in FIG. 12, a SiC film 80 having a high thermal conductivity is formed of ceramics or the like on insulating film 40, heat dissipation part 50 and source wiring part 72, and SiC film 80 is formed. A semiconductor device having a structure in which the heat dissipation plate 60 is formed may be used. This can reduce the parasitic capacitance. In the semiconductor device having the structure shown in FIG. 12, a SiC film 80 having a film thickness of 1 μm is formed by sputtering on the insulating film 40, the heat dissipation part 50, and the source wiring part 72, and the formed SiC film 80 is formed. It can be manufactured by forming the heat dissipation plate 60 on.

[Second Embodiment]
Next, a second embodiment will be described. This Embodiment is a semiconductor device, a power supply device, and a high frequency amplifier.

The semiconductor device according to the present embodiment is a discrete package of any one of the semiconductor devices according to the first embodiment. A semiconductor device thus discretely packaged will be described with reference to FIG. Note that FIG. 13 schematically shows the inside of a discretely packaged semiconductor device, and the arrangement of electrodes and the like are different from those shown in the first embodiment.

First, the semiconductor device manufactured in the first embodiment is cut by dicing or the like to form a HEMT semiconductor chip 410 of a GaN-based semiconductor material. The semiconductor chip 410 is fixed onto the lead frame 420 with a die attach agent 430 such as solder. The semiconductor chip 410 corresponds to the semiconductor device according to the first embodiment.

Next, the gate electrode 411 is connected to the gate lead 421 by the bonding wire 431, the source electrode 412 is connected to the source lead 422 by the bonding wire 432, and the drain electrode 413 is connected to the drain lead 423 by the bonding wire 433. The bonding wires 431, 432, 433 are made of a metal material such as Al. In addition, in the present embodiment, the gate electrode 411 is a gate electrode pad and is connected to the gate electrode 31 of the semiconductor device according to the first embodiment. Further, the source electrode 412 is a source electrode pad and is connected to the source electrode 32 of the semiconductor device according to the first embodiment. Further, the drain electrode 413 is a drain electrode pad and is connected to the drain electrode 33 of the semiconductor device according to the first embodiment.

Next, resin molding is performed with the mold resin 440 by the transfer molding method. In this manner, a HEMT discrete packaged semiconductor device using a GaN-based semiconductor material can be manufactured.

Next, the power supply device and the high frequency amplifier according to the present embodiment will be described. The power supply device and the high frequency amplifier according to the present embodiment are the power supply device and the high frequency amplifier using any of the semiconductor devices according to the first embodiment.

First, the power supply device according to the present embodiment will be described with reference to FIG. The power supply device 460 in the present embodiment includes a high voltage primary side circuit 461, a low voltage secondary side circuit 462, and a transformer 463 disposed between the primary side circuit 461 and the secondary side circuit 462. The primary side circuit 461 includes an AC power supply 464, a so-called bridge rectifier circuit 465, a plurality of switching elements (four in the example shown in FIG. 14) 466, one switching element 467, and the like. The secondary circuit 462 includes a plurality of switching elements (three in the example shown in FIG. 14) 468. In the example shown in FIG. 14, the semiconductor device according to the first embodiment is used as the switching elements 466 and 467 of the primary side circuit 461. The switching elements 466 and 467 of the primary side circuit 461 are preferably normally-off semiconductor devices. Further, the switching element 468 used in the secondary side circuit 462 uses a normal MISFET (metal insulator semiconductor field effect transistor) formed of silicon.

Next, the high frequency amplifier according to the present embodiment will be described with reference to FIG. The high frequency amplifier 470 in the present embodiment may be applied to, for example, a power amplifier for a base station of a mobile phone. The high frequency amplifier 470 has a transistor 471, an input matching circuit 472, an output matching circuit 473, and a resistor 474. The semiconductor device according to the first embodiment is used for the transistor 471. An input matching circuit is connected to the gate of the transistor 471, an output matching circuit 473 and a resistor 474 are connected to the drain, and the source is grounded. The signal from the oscillator 475 is input to the input matching circuit 472. After the impedance is adjusted in the input matching circuit 472, it is input to the gate of the transistor 471 and output from the drain of the transistor 471 to the output matching circuit 473. To be done. After that, the output matching circuit 473 adjusts the impedance, and then outputs the result to the antenna 476 and the like.

[Third Embodiment]
A microwave heating apparatus according to the third embodiment will be described based on FIG. The microwave heating device in this embodiment has a microwave generator 510 for generating microwaves, a heating chamber 520, a control unit 530, and the like. An object to be heated 540 to be heated by the microwave heating device in the present embodiment is placed in heating chamber 520.

The microwave generator 510 is connected to the heating chamber 520, and by supplying the microwave generated in the microwave generator 510 into the heating chamber 520, the object to be heated contained in the heating chamber 520. 540 can be heated. The microwave generator 510 is formed of the semiconductor device according to the first embodiment, and the frequency and power of the generated microwave can be changed under the control of the control unit 530.

[Fourth Embodiment]
Next, a fourth embodiment will be described.

First, an exhaust emission control device according to the fourth embodiment will be described with reference to FIG.

Exhaust gas purification device 600 in the present embodiment has a particulate collection part 610, an oxidation catalyst part 611, a housing part 620, a microwave generator 630, an incident power sensor 641, a reflection power sensor 642, a control part 650 and the like. ing.

The particulate matter collecting portion 610 is an object to be heated in the present embodiment, and is made of DPF or the like. The DPF has, for example, a honeycomb structure in which adjacent vents are alternately closed, and exhaust gas is discharged from vents different from the vents at the inlet. The oxidation catalyst portion 611 is formed of an oxidation catalyst such as DOC (Diesel Oxidation Catalyst).

The housing 620 is made of a metal material such as stainless steel, and covers a housing body 620a surrounding the oxidation catalyst portion 611 and the particulate collection portion 610, and an inlet 620b connected to the housing body 620a. And a discharge port 620c. In the exhaust emission control device according to the present embodiment, exhaust gas such as exhaust gas from the engine or the like enters the housing portion 620 through the inlet 620b from the direction indicated by the dashed arrow A, and is installed in the housing body portion 620a. It is purified by passing through the oxidation catalyst section 611 and the particulate collection section 610. After that, the exhaust gas purified by the oxidation catalyst unit 611 and the particulate collection unit 610 is discharged from the discharge port 620c in the direction shown by the broken line arrow B.

In the housing 620, the oxidation catalyst portion 611 and the particulate collection portion 610 are arranged in this order from the suction port 620b toward the discharge port 620c. The oxidation catalyst unit 611, which oxidizes the components contained in the exhaust gas entering from the suction port 620b, for example, the NO contained in the exhaust gas to the stronger oxidizing power NO _2. Fine particles such as PM are collected in the fine particle collecting unit 610, and when burning and removing the collected fine particles such as PM, NO ₂ generated in the oxidation catalyst unit 611 is used. The fine particles such as PM collected in the fine particle collecting unit 610 are soot and contain a large amount of C (carbon). When burning fine particles such as PM collected in the fine particle collecting section 610 to remove them, by flowing NO ₂ , C and NO ₂ chemically react with _{each other} to generate CO ₂ . This makes it possible to efficiently remove fine particles such as PM collected in the fine particle collection unit 610.

The microwave generator 630 is connected to the housing 620 and can generate microwaves of 1 GHz to 10 GHz by changing the frequency. Further, by irradiating the fine particle collecting section 610 with the microwave generated in the microwave generator 630, the fine particles such as PM collected in the fine particle collecting section 610 can be burned and removed. In the present embodiment, the microwave generator 630 uses the semiconductor device according to the first embodiment. Since the semiconductor device according to the first embodiment has good heat dissipation characteristics, it can be operated well even under such a high temperature environment.

The incident power sensor 641 and the reflected power sensor 642 are provided between the housing 620 and the microwave generator 630. The incident power sensor 641 measures the power of the incident wave that enters the housing 620 from the microwave generator 630, and the reflected power sensor 642 includes the housing 620 of the microwaves that enter the housing 620. Measure the power of the reflected wave that returns more. The control unit 650 mainly controls the microwave generator 630 to generate microwaves to heat the particle collecting unit 610.

FIG. 18 shows an automobile 660 according to the present embodiment, to which an exhaust emission control device 600 according to the present embodiment is attached. In automobile 660 according to the present embodiment, exhaust gas generated in automobile 660 can be purified by exhaust emission purification device 600.

FIG. 19 shows an information system according to this embodiment. The information system according to the present embodiment has a plurality of radio base stations 670 and a data center 671 connected to the plurality of radio base stations 670. A wireless device 661 is mounted on the automobile 660 and can perform wireless information communication with any of the wireless base stations 670. In the present embodiment, exhaust emission control device 600 detects the amount of soot accumulated in particulate collection portion 610 of exhaust emission control device 600 attached to automobile 660. The amount of soot accumulated in the particulate matter collection unit 610 detected by the exhaust emission control device 600 is transmitted to the wireless base station 670 via the wireless device 661 mounted on the automobile 660 and collected in the data center 671. .. The data center 671 predicts the amount of soot that will be deposited later based on the amount of deposited soot, and searches for the optimum route. The optimum route thus obtained is transmitted from the wireless base station 670 to the automobile 660. The semiconductor device according to the first embodiment is used for the exhaust emission control device 600 attached to the automobile 660, but can also be used for the wireless base station 670.

In addition to the above, the semiconductor device according to the first embodiment can be used in a radar, an airplane, a ship, an airfield, a seaport, and the like.

Although the embodiments have been described in detail above, the invention is not limited to the specific embodiments, and various modifications and changes can be made within the scope of the claims.

With respect to the above description, the following additional notes are disclosed.
(Appendix 1)
A semiconductor layer formed of a semiconductor on the substrate,
A gate electrode, a source electrode and a drain electrode formed on the semiconductor layer,
An insulating film formed on the semiconductor layer, the gate electrode, the source electrode and the drain electrode,
A heat dissipation portion formed on the insulating film,
Have
The semiconductor device is characterized in that the heat dissipation portion is formed such that a width thereof on a side farther from the side closer to the semiconductor layer is wider.
(Appendix 2)
2. The semiconductor device according to appendix 1, wherein the heat dissipation portion is formed of any one of metal, ceramics, and carbon nanotube.
(Appendix 3)
3. The semiconductor device according to appendix 1 or 2, wherein a heat dissipation plate made of metal or ceramics is formed on the insulating film and the heat dissipation part.
(Appendix 4)
4. The semiconductor device according to appendix 3, wherein the heat dissipation plate is formed above the gate electrode and the source electrode.
(Appendix 5)
5. The semiconductor device according to appendix 3 or 4, wherein the heat dissipation plate is not formed above the drain electrode.
(Appendix 6)
4. The semiconductor device according to appendix 3, wherein a film made of ceramics is provided between the heat dissipation plate and the insulating film and the heat dissipation portion.
(Appendix 7)
5. The semiconductor device according to appendix 3 or 4, wherein the source electrode is connected to the heat dissipation plate by a source wiring portion that penetrates the insulating film.
(Appendix 8)
8. The semiconductor device according to any one of appendices 1 to 7, wherein the heat dissipation portion is formed above the drain electrode side of the gate electrode.
(Appendix 9)
9. The semiconductor device according to any one of appendices 1 to 8, wherein the heat dissipation portion is formed above the gate electrode side of the semiconductor layer in a region between the gate electrode and the drain electrode. ..
(Appendix 10)
10. The semiconductor device according to any one of appendices 1 to 9, wherein the semiconductor layer is made of a nitride semiconductor.
(Appendix 11)
The semiconductor layer is a first semiconductor layer formed on the substrate,
A second semiconductor layer formed on the first semiconductor layer;
Is formed by
11. The semiconductor device according to any one of appendices 1 to 10, wherein the gate electrode, the source electrode, and the drain electrode are formed on the second semiconductor layer.
(Appendix 12)
The first semiconductor layer is formed of a material containing GaN,
12. The semiconductor device according to appendix 11, wherein the second semiconductor layer is formed of a material containing AlGaN or InAlN.
(Appendix 13)
A power supply device comprising the semiconductor device according to any one of appendices 1 to 12.
(Appendix 14)
An amplifier comprising the semiconductor device according to any one of appendices 1 to 12.
(Appendix 15)
A microwave generator including the semiconductor device according to any one of appendices 1 to 12,
A heating chamber where the object to be heated is installed,
A heating device comprising:
(Appendix 16)
A microwave generator including the semiconductor device according to any one of appendices 1 to 12,
A housing containing a particulate collection unit,
An exhaust emission control device comprising:
(Appendix 17)
An automobile having the exhaust emission control device according to appendix 16.
(Appendix 18)
The vehicle described in Appendix 17,
A wireless base station that performs wireless information communication with the vehicle,
An information system comprising:

10 substrate 11 buffer layer 21 electron transit layer 21a 2DEG
22 electron supply layer 31 gate electrode 32 source electrode 33 drain electrode 40 insulating film 50 heat dissipation part 60 heat dissipation plate 72 source wiring part

Claims (10)

A semiconductor layer formed of a semiconductor on the substrate,
A gate electrode, a source electrode and a drain electrode formed on the semiconductor layer,
An insulating film formed on the semiconductor layer, the gate electrode, the source electrode and the drain electrode,
A heat dissipation portion formed on the insulating film,
A film formed of ceramic on the insulating film and the heat dissipation portion,
A heat sink formed of metal or ceramics on the film,
Have
The semiconductor device is characterized in that the heat dissipation portion is formed such that a width thereof on a side farther from the side closer to the semiconductor layer is wider. The semiconductor device according to claim 1, wherein the heat dissipation part is formed of any one of metal, ceramics, and carbon nanotubes. 3. The semiconductor device according to claim 1, wherein the heat dissipation part is formed above the drain electrode side of the gate electrode. The heat radiating portion, a semiconductor according to any one of claims 1 to 3, characterized in that the gate electrode is formed above the gate electrode side of the semiconductor layer in the region between the drain electrode apparatus. Power supply, characterized in that it comprises a semiconductor device according to any one of claims 1 to 4. Amplifier, characterized in that it comprises a semiconductor device according to any one of claims 1 to 4. A microwave generator having a semiconductor device according to any one of claims 1 to 4,
A heating chamber where the object to be heated is installed,
A heating device comprising: A microwave generator having a semiconductor device according to any one of claims 1 to 4,
A housing containing a particulate collection unit,
An exhaust emission control device comprising: An automobile having the exhaust emission control device according to claim 8 . An automobile according to claim 9 ;
A wireless base station that performs wireless information communication with the vehicle,
An information system comprising:

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