JP2000101064A - ELECTRODE, SiC ELECTRODE, AND SiC DEVICE - Google Patents

Abstract

PROBLEM TO BE SOLVED: To realize an ohmic structure, without using a high-temperature alloy treatment and a high carrier ion implantation process by a method, wherein the ohmic contact structure is composed of a specified conductivity-type semiconductor and a conductive oxide electrode, which is of the same conductivity type as with the semiconductor formed on the semiconductor. SOLUTION: An electrode comes into ohmic contact with an SiC semiconductor 1 in a manner in which a conductive oxide 2 is brought into contact with the SiC semiconductor, and a metal electrode 3 is brought into contact with the conductive oxide 2, where the conductive oxide 2 comes into ohmic contact with the SiC semiconductor 1, and the metal electrode 3, coming into contact with the conductive oxide 2. Ti or Al that comes into ohmic contact with a conductive oxide an low in contact resistance, is used as a metal material that comes into contact with the conductive oxide 2. Furthermore, an N-type SiC semiconductor is formed film-like through a CVD method carried out in an N atmosphere, and a P-type SiC semiconductor is formed a film-like through a CVD method in an atmosphere that contains either Al or B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a SiC (silicon carbide) electrode and a SiC device using the same, and more particularly, to an electrode capable of making ohmic contact with SiC.
The present invention relates to a SiC electrode and a SiC device.

[0002]

2. Description of the Related Art A SiC semiconductor has larger physical properties such as a melting point, an energy gap, a dielectric breakdown electric field, a thermal conductivity, and a saturation velocity than other semiconductors generally used at present (for example, Si). It is thermally, chemically and mechanically stable and has excellent radiation resistance.

[0003] For the formation of an ohmic electrode of SiC, conventionally, for example, for p-type SiC, Al,
It is known that an Al / Ti laminated film, an Al-Ti alloy, or the like is vapor-deposited on a silicon carbide surface and then subjected to a high-temperature alloy treatment at 900 to 1100 ° C. N-type Si
For C, Ni, Ni / Ti / W laminated film, etc.
It is known that a high-temperature alloying treatment is performed after vapor deposition on the C surface.

As another example, in addition to the high-temperature alloy treatment, the resistance of silicon carbide in a region where an electrode is in contact is increased by increasing the impurity concentration (about 10 ¹⁹ cm ⁻³ ). Methods such as making low ohmic contact are known.

[0005]

However, when high-temperature alloying is required, only heat-resistant materials can be used in the manufacture of SiC devices, and there are significant restrictions on materials in the device manufacturing process. It will be. In addition, the electrode material aggregates during the high-temperature alloy treatment, which makes it difficult to form a uniform ohmic electrode.

On the other hand, in order to form a region having a high impurity concentration in silicon carbide, an ion implantation method is used, but the ion implantation deteriorates the crystallinity of silicon carbide.
Further, when surface treatment is performed on SiC, the treatment hinders the efficiency of the semiconductor device manufacturing process.

Accordingly, an object of the present invention is to provide an electrode capable of obtaining ohmic contact without requiring high-temperature alloy treatment and high carrier ion implantation, and an SiC device using the same.

[0008]

In order to solve the above-mentioned problems, an electrode according to the present invention comprises a semiconductor having a predetermined conductivity type and a conductive material formed on the semiconductor and having the same conductivity type as the conductivity type. And an electrode made of a conductive oxide. The electrode according to the present invention is the electrode according to claim 1, wherein the semiconductor and the conductive oxide have substantially the same band gap.

The SiC electrode according to the present invention is provided with an electrode made of SiC of a predetermined conductivity type and a conductive oxide of the same conductivity type formed in contact with the SiC. It is.

As shown in FIG. 2, for example, SrTi
Since the band structure of a conductive oxide such as SrTiO ₃ obtained by doping O ₃ with a predetermined amount of Nb is a wide gap material similar to SiC, a continuous band connection is formed by joining these materials. A Schottky barrier, as envisioned and caused by contact between metal and semiconductor, does not occur. The condition for the ohmic contact is determined by the magnitude of ΔE shown in FIG. ΔE is determined only by the position of the Fermi level (carrier concentration) Ef of SiC.

Here, for example, a SiC carrier concentration of 10
^{For 16} cm ^-3 , Ef is 130 mV energetically below the bottom of the conduction band. At this time, ΔE = 13
0 mV (ΔE = 20 mV if 10 ¹⁸ cm ^-3 )
Which is an amount that can be treated as an ohmic contact. Therefore, if the doping amount of SiC is 10 ¹⁶ cm ⁻³ or more, ohmic contact is possible, and in the present invention, high doping of SiC is not required, and high-temperature alloy treatment is not required.

In the SiC electrode of the present invention, the electrode made of a conductive oxide has a film made of the oxide and a metal body formed on the film.

Here, the oxide film has ohmic characteristics with SiC, and the metal body has ohmic characteristics with the oxide film. The metal body may be a metal film or a metal wiring. In an electronic device, the conductive oxide itself has a higher resistance than a metal for wiring connection such as gold. Therefore, it is conceivable to connect a lead such as gold to an electrode made of a conductive oxide of the device. The conductive oxide has a low-resistance connection state with a predetermined metal, for example, a metal such as Ti or Al. Therefore, an electrode in which a predetermined metal is provided on the conductive oxide as, for example, a metal for wiring connection (or a metal for wiring connection obtained by further providing a connection metal for lead via a predetermined metal such as Ti or Al) is configured. If this is the case, connection to other circuits (devices) can be made with low resistance. Note that in this case, the conductive oxide has a minimum distance (or film thickness) that is sufficient as long as a low-resistance ohmic contact can be made with SiC and a low-resistance ohmic contact with a metal (for example, a metal for wiring connection). For example, it is desirable to provide over 500 degrees.

[0014] In the SiC electrode according to the present invention, the conductive oxide is an oxide having a regular composition.
An oxide having a specific resistance of about 1 Ωcm or less, for example, in the range of 1 to 10 ⁻⁷ Ωcm can be used.

Some conductive oxides have the highest conductivity when formed into a regular composition, and some have metallic properties. According to such an oxide, it becomes possible to use it as an electrode structure without implanting impurities. Note that, in addition to those described in the embodiment, such conductive oxides include titanium oxide (TiO), lanthanum nickel oxide (LaNiO ₃ ), lanthanum copper oxide (LaCuO ₃ ), and copper ruthenium. Oxide (CuRuO
₃ ), strontium iridium oxide (SrIr
O ₃ ), strontium chromium oxide (SrCr
O ₃ ), lithium titanium oxide (LiTi ₂ O ₄ ), ruthenium oxide (RuO ₂ ), osmium oxide (Os)
O ₂ ), iridium oxide (IrO ₂ ), molybdenum oxide (MoO ₂ ), tungsten oxide (WO ₂ ), rhenium oxide (ReO ₂ ), rhodium oxide (RhO ₂ ), β platinum oxide (βPtO ₂ ), lanthanum titanate (LaTi
O ₃ ), ruthenium oxide (ReO ₃ ), copper aluminum oxide (CuAlO ₂ ), copper gallium oxide (CuGaO ₂ )
Of any one of the above.

These oxides are also described in the embodiments.
As described above, the specific resistance is small, and
Contact can be made. In addition, these conductive
When the SiC semiconductor of the oxide is n-type, LaTi
O _ThreeOr ReO_ThreeIs used. LaTiO_ThreeRatio
Resistance is 10^-FiveΩcm and ReO_ThreeHas a specific resistance of 10^-7
Ωcm. On the other hand, when the SiC semiconductor is p-type, C
uAlO_TwoOr CuGaO_TwoIs used. CuA
10_TwoAnd CuGaO_TwoAre approximately 1 Ωcm
You.

Further, in the SiC electrode according to the present invention, the conductive oxide is an oxide having a normal composition and an impurity doped with impurities, and having a specific resistance of 1 Ωcm or less, for example, 1 to 10 ⁻⁷ Ωcm. Things.

Some conductive oxides exhibit conductivity by deviating from the normal composition to generate oxygen vacancies or interstitial ions. Therefore, a conductive oxide can be obtained by doping a predetermined impurity into an insulating oxide having a regular composition, and by using such a conductive oxide, an ohmic contact with SiC can be obtained. Can be. Note that, in addition to those described in the embodiment, such conductive oxides include tin oxide (SnO ₂ ), indium oxide (In ₂ O ₃ ), and thallium oxide (Tl).
₂ O ₃ ), thallium fluoride (TlOF) and the like.

Further, in the SiC electrode according to the present invention, the oxide used as the electrode is made of SrTiO ₃ ,
It is any oxide of In ₂ O ₃ .

It has been found that remarkable conductivity can be obtained by doping a given impurity with such an oxide. By using such a conductive oxide, SiC can be obtained.
An electrode capable of making ohmic contact with the electrode.

In the SiC electrode according to the present invention, the SrTiO ₃ contains Nb, Ta,
And any one of La. In ₂ O ₃ contains Sn as an impurity.

As described in the embodiment, SrTiO ₃ is doped with any of Nb, Ta, and La, and In ₂ O ₃ is doped with Sn. Then, conductivity is generated in these oxides, and ohmic contact with SiC can be obtained. Therefore, an electrode having ohmic contact can be obtained by using such a conductive oxide.

Further, the SiC device according to the present invention is, for example, an electronic device as shown in FIGS.
An electrode according to any one of claims 1 to 7 is used as an iC electrode.

In such a SiC device, its electrode can be obtained without performing high-temperature alloying treatment, high-doping or special surface treatment, so that the manufacturing process is simplified and restrictions on high-temperature resistant materials and the like are relaxed. You. Furthermore,
Since SiC is used for the semiconductor, stable and reliable operation is possible even under severe environments such as high temperature and radiation.

In the SiC device according to the present invention, for example, the electrodes (source and drain electrodes) of MOSFET electrodes can be obtained without performing high-temperature alloying, high-doping or special surface treatment. Is simplified, and restrictions such as high-temperature resistant materials are eased. Further, since the semiconductor is made of SiC, stable and reliable operation can be performed even under severe environments such as high temperature and radiation. Note that the SiC on which the source, the drain, and the like are provided may be a SiC substrate.
A structure in which a SiC film is formed on a C substrate may be used. In the embodiment, a metal for wiring connection is provided on the conductive oxide.

In the SiC device according to the present invention, for example, an electrode of a thermoelectric element can be obtained without performing high-temperature alloy treatment, high-doping or special surface treatment, so that the manufacturing process is simplified. In addition, restrictions such as high temperature resistant materials are also eased. Further, since the semiconductor is made of SiC, stable and reliable operation can be performed even under severe environments such as high temperature and radiation.

A copper electrode is generally used for the metal electrode of the thermoelectric element because of its good thermal conductivity. Therefore, a predetermined metal (for example, Ti,
By interposing Al), a low-resistance electrical connection between SiC and the copper electrode can be obtained. Al, Ti, or the like is applied as the predetermined metal.

[0028]

Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a sectional side view of an electrode according to the first embodiment. This electrode is formed by bringing a conductive oxide 2 into contact with a SiC semiconductor 1 and further bringing a metal electrode 3 into contact with the conductive oxide 2. The conductive oxide 2 and the metal electrode 3 make ohmic contact with each other.

Here, when the SiC semiconductor 1 is n-type,
In the conductive oxide 2, as a conductive oxide having a regular composition,
LaTiO ₃ or ReO ₃ is used. LaTi
The specific resistance of O ₃ is 10 ⁻⁵ Ωcm, and the specific resistance of ReO ₃ is 10 ⁻⁷ Ωcm.

The conductive oxide 2 can also be obtained by doping an insulating oxide having a regular composition with a predetermined impurity. In this case, for example, SrTiO doped with any of Nb, Ta, and La is used. ₃ or In ₂ O ₃ doped with Sn is used.

Here, SrTiO_ThreeThe above dopant to
Is set at 0.1 to 5 atm%.
Specific resistance is 1-10^-FourΩcm. In addition, the above to Sn
The doping amount of the dopant is set to 5 to 10 wt%.
When the specific resistance is 10^-Four-10 ^-FiveΩcm.

On the other hand, when the SiC semiconductor 1 is p-type,
The conductive oxide 2 has a regular composition of conductive oxide
uAlO_TwoOr CuGaO_TwoIs used. CuA
10 _TwoAnd CuGaO_TwoAre approximately 1 Ωcm
You.

In the p-type SiC semiconductor, an oxide which becomes conductive by doping an insulating oxide having a regular composition with a dopant has not been found so far. If oxides are found,
The doped conductive oxide is included in the conductive oxide of the present invention.

The method for producing a conductive oxide obtained by doping an insulating oxide with a dopant includes sputtering,
There are laser ablation and reactive co-evaporation. For example,
S formed by doping SrTiO ₃ with Nb by sputtering
The method for producing rTiO ₃ (hereinafter referred to as Nb-SrTiO ₃ ) is such that the target is Nb-SrTiO ₃ , the sputtering gas is Ar + O ₂ (10 to 50%), and the total pressure is 0.01 to 1 torr.
It is performed at a film formation temperature of 500 to 700 ° C. as r. In addition, Nb-SrT by laser ablation
Preparation of iO ₃ is a target Nb-SrTiO _3, the atmospheric gas as O ₂ (0.01~1torr), 50
This is performed at a film formation temperature of 0 to 700 ° C. Furthermore, preparation of Nb-SrTiO ₃ by reactive co-evaporation is an evaporation source Nb-SrTiO _3, the atmospheric gas O ₂ (10 ^-6 ~1
As 0 ^-5 torr), it is carried out under a film formation temperature of 500 to 700 ° C..

In FIG. 1, as the metal material which comes into contact with the conductive oxide 2, Ti or Al which can obtain a low-resistance ohmic contact with the conductive oxide is used. The n-type SiC semiconductor is, for example, a CV in an atmosphere containing N.
A film is obtained by the method D, and a bulk is obtained by the sublimation method. The p-type SiC semiconductor is A
A film is obtained by a CVD method in an atmosphere containing either l or B, and a bulk is obtained by a sublimation method. The carrier concentration of SiC is 10 ¹⁶ cm ^-3 to 1
0 ¹⁸ cm ^-3 .

FIG. 2 shows N, obtained by the electrodes described above.
₃ shows a band structure of b-SrTiO ₃ and an n-type SiC semiconductor. As shown in FIG. 2, the band structure of the conductive oxide has a degenerate semiconductor (Fermi level is in the conduction band) structure. The degeneracy width is determined by the carrier concentration, and the specific resistance of the oxide is determined by the carrier concentration. In order to reduce the electrode resistance, it is desirable that the carrier concentration be as high as possible.

Since the band structure of the conductive oxide is a wide-gap material similar to that of SiC, a continuous band connection is assumed in the bonding of these materials, and a shot such as that generated by contact between the metal and the semiconductor is assumed. There are no key barriers. The condition for the ohmic contact is determined by the magnitude of ΔE shown in FIG. For example, if ΔE = 1 eV, ohmic contact cannot be said. Also, ΔE
Is determined only by the position of the Fermi level (carrier concentration) Ef of SiC.

Here, for example, an SiC carrier concentration of 10
^{For 16} cm ^-3 , Ef is 130 mV energetically below the bottom of the conduction band. At this time, ΔE = 13
0 mV (ΔE = 20 mV if 10 ¹⁸ cm ^-3 )
Which is an amount that can be treated as an ohmic contact. Therefore, if the doping amount of SiC is 10 ¹⁶ cm ⁻³ or more, ohmic contact is possible, and in the present invention, high doping of SiC is not required, and high-temperature alloy treatment is not required.

The above-mentioned n-SiC and p-SiC
The following summarizes the types of conductive oxides, impurities and their doping amounts, and the specific resistances obtained thereby.

[0040]

[Table 1] n-SiC (doping amount 10 ¹⁶ cm ^-3 or more) Conductive oxide Doping amount (resistivity) Any one of Nb, Ta, and La doped SrTiO ₃ 0.01-1 atm% (1-10 ^-4 Ωcm) Sn-doped In ₂ O ₃ (ITO) 0.01-1 wt% (10 ^-4 -10 ^-5 Ωcm) LaTiO _{3 not} doped (10 ^-5 Ωcm) ReO _{3 not} doped (10 ^-7 Ωcm)

[0041]

Table 2 p-SiC (doping amount 10 ¹⁶ cm ^-3 or more) Conductive oxide Doping amount (resistivity) CuAlO ₂ without doping 1 Ωcm CuGaO ₂ without doping 1 Ωcm

Embodiment 2 In the second embodiment, a SiC using the electrode of the first embodiment as a thin film electrode of a deposited SiC is used.
1 shows an example of a device. Figure 3 shows an n-channel MOSFET
And FIG. This MOSFET
Is a p-type SiC substrate 1A as shown in FIG.
Source region 1B and drain region 1C provided above
And source and drain regions 1B,
1C and a conductive oxide film 2 provided on the source and drain regions 1B and 1C.
A, 2B, wiring connection metal layers 3A, 3B provided on the conductive oxide films 2A, 2B, and a gate electrode 6 provided on the gate oxide film 5.

Here, the conductive oxide films 2A and 2B and the wiring connection metal layers 3A and 3B provided thereon are
Each constitutes a source and drain electrode.

Hereinafter, a method of manufacturing this MOSFET will be described with reference to FIG.
It will be described according to. FIGS. 3A to 3C show a process of forming a source / drain region. First, as shown in FIG. 3A, a mask 7 for ion implantation (doping) is formed on a p-type SiC substrate 1A. . Here, the p-type SiC substrate 1
As A, Al is 1 × 10 ¹⁵ -1 × 10 ¹⁸ as an impurity.
A SiC single crystal substrate doped with cm ^-3 was used. The mask 7 is made of SiO _{2 having} a thickness of 1 μm on the p-type SiC substrate 1A.
After a film is formed by a CVD method or the like, the film is formed by a SiO ₂ evaporation method obtained through a photolithography process and an etching process.

Next, as shown in FIG. 3B, n-type impurity regions 1B and 1C are formed in the p-type SiC substrate 1A by an implantation method. Here, the implanted impurity is N or P,
The injection temperature is 500 to 1000 ° C., and the injection amount is 1 × 10 ¹⁸ −
It is 1 × 10 ²¹ cm ⁻³ . After that, the mask 7 is removed by etching, and furthermore, an annealing process for activating the impurities implanted into the n-type impurity regions 1B and 1C so as to function as carriers is performed at 800 to 1500 ° C.
This is performed in a vacuum or inert gas, and as shown in FIG. 3C, the source region 1B and the drain region 1C
Get.

Next, a gate oxide film shown in FIGS. 3D to 3E is formed. First, in (d), the p-type S
The iC substrate 1A is oxidized at 1200 ° C. in an oxygen atmosphere to form a 500 ° -thick SiO ₂ film 5A on the surface. Then, as shown in (e), the source region 1B and the drain region 1C are subjected to photolithography and etching steps.
The gate oxide film 5 is obtained by removing the upper oxide film 5A.

Next, source, drain and gate electrodes shown in FIGS. 3 (f) to 3 (h) are formed. First, p-type Si
A conductive oxide having a thickness of 500 ° is formed on the C substrate 1A by a sputtering method or the like, and is subjected to a photolithography and etching process. As shown in FIG. 3F, contact electrodes are formed on the source and drain regions 1B and 1C. Of conductive oxides 2A and 2B are formed. Here, SrTiO ₃ doped with 1 atm% of Nb was used as the conductive oxide.

Next, on the p-type SiC substrate 1A, a thickness of 20
Al or Ti is formed as a contact layer to the wiring layer with a thickness of 00 ° by a vacuum evaporation method or the like, and is subjected to a photolithography and etching process to form a conductive oxide film 2 as shown in FIG.
The metal layers 3A and 3B for wiring connection are formed on A and 2B.

Finally, on the p-type SiC substrate 1A, the thickness 2
A polycrystalline Si of 000 ° is formed by a sputtering method or the like, and is subjected to a photolithography and etching process so that the gate electrode 6 is formed so that the polycrystalline Si exists only on the gate oxide film 5 as shown in FIG. To form

As described above, in the SiC device according to the second embodiment, since the metal electrode layer as the wiring layer is connected via the conductive oxide film (contact electrode) that makes ohmic contact with SiC, the high-temperature alloy is used. No treatment is required, and it is not necessary to provide a high carrier layer on SiC.

Embodiment 3 FIG. Embodiment 3 shows an example of an electronic device using the electrode of Embodiment 1 as a SiC bulk electrode. FIG. 4 is a diagram showing a thermoelectric element using a SiC bulk and a method for manufacturing the same. As shown in FIG. 4C, the thermoelectric element includes n-type first and second conductive oxides (2D-1, 2D-2) provided with n-type SiC1D interposed therebetween.
D-2), the p-type third and fourth conductive oxides (2E-1 and 2E-2) provided with the p-type SiC1E interposed therebetween, the n-type conductive oxide 2D-2, and the p-type conductive oxide. Metal electrode 8 connected to conductive oxide 2E-2 via metal film 3D, and second metal electrode 8 connected to n-type conductive oxide 2D-1 via metal film 3E.
The metal film 10 is formed on the metal electrode 10 and the p-type conductive oxide 2E-1.
And a third metal electrode 9 connected through E.

Hereinafter, a method for manufacturing the thermoelectric element will be described with reference to FIG. First, as shown in (a), CuAlO ₂ (2E-1, 2E-2) which is a p-type conductive oxide is formed on both sides of p-type SiC1E obtained by a sublimation method by a sputtering method or the like. (Thickness 500 mm). Also, n
Nb, which is an n-type conductive oxide, is placed on both sides of the type SiC1D by 1
strontium titanate (2D-
1,2D-2) is formed by sputtering or the like (thickness: 500 °).

Next, as shown in (b), the conductive oxides (2D-1, 2D-2, 2E-
1, 2E-2) as contact metal films 3D and 3E on the film
An Al film or a Ti film is formed by a vacuum deposition method or the like (thickness: 10 μm). Then, as shown in (c), the first metal electrode (copper electrode) 8 is soldered over the vacuum-deposited contact metal films 3D, 3D, and the first metal electrode (copper electrode) 8 is spread over the contact metal films 3E, 3E. 2. Third metal electrode (copper electrode) 9, 10
And solder them.

In the thermoelectric element thus manufactured, ohmic contact between the metal electrodes (for example, copper electrodes) 8 to 10 and the SiC semiconductor can be easily obtained, and the resistance can be reduced by the contact metal layer. The reason why copper is used for the metal electrode is that copper has excellent thermal conductivity and can increase the power / heat exchange efficiency of the thermoelectric element.

Embodiment 4 FIG. 5 is a sectional view showing an n-channel junction field effect transistor (JFET) as another example of an electronic device using SiC. This JFE
T has p-type regions 1G and 1G on each of two surfaces facing the n-type SiC 1F, and these regions have p-type conductive oxide films 2F and 2F, respectively.
Wiring connection metal films 3F, 3F made of 1 and Ti are provided. On the other opposing surface of the n-type SiC 1F, wiring connection metal films 3G and 3H made of Al and Ti for source and drain are provided via n-type conductive oxide films 2G and 2H, respectively. Have been.

Embodiment 5 FIG. 6 is a sectional view showing an n-channel junction field effect transistor (MESFET) as another example of an electronic device using SiC. This M
In the ESFET, a Schottky gate electrode 3I made of, for example, a Pt film is provided on an n-type SiC1H, and Al and Al are provided on both sides thereof via n-type conductive oxide films 2I and 2J.
Wiring connection metal films 3J and 3K made of Ti are provided;
These are source and drain electrodes, respectively.

Embodiment 6 FIG. FIG. 7 is a sectional view showing a thyristor as another example of an electronic device using SiC. The thyristor is a p-layer 1 of SiC from the left end in the figure.
I, n layer 1J, p layer 1K, and n layer 1L are provided alternately,
A is formed on the leftmost p-layer 1I via the p-type conductive oxide film 2K.
A wiring connection metal film 3L made of 1 and Ti is provided to form an anode electrode. Also, a wiring connection metal film 3M made of Al and Ti is provided on the right end n-layer 1L via an n-type conductive oxide film 2L to form a cathode electrode. Furthermore, the p-layer 1 adjacent to the rightmost n-layer 1L
A wiring connection metal film 3N made of Al and Ti is provided on K via a p-type conductive oxide film 2M to form a gate electrode.

Embodiment 7 FIG. FIG. 8 shows an insulated gate bipolar transistor (IGBT) using SiC, in which an n-type SiC1M is formed in an upper half of a substrate and a p-type SiC1N is formed in a lower half. On the lower surface of the p-type SiC 1N, a wiring connection metal film 3S made of Al and Ti is provided via a p-type conductive oxide film 2N to form a collector electrode. On both sides of the upper surface of the n-type SiC1M, a p-layer 1
P, 1Q are provided, and an electrode on which wiring connection metal films 3P, 3Q made of Al and Ti are provided via n-type conductive oxide films 2Q, 2P. Among these electrodes, the left electrode is used as an emitter electrode, and the right electrode is used as a gate voltage control terminal.

The wiring connection metal film 3 made of Al and Ti is formed on the upper surface of the n-type SiC 1M via the gate oxide film 5B.
R is provided. The n-type conductive oxide films 2Q, 2Q
The n-layers 1R, 1S and 1T, 1U are provided in the p-layers 1P, 1Q, respectively, in the peripheral portion of P on the substrate side and between the gate electrode and the emitter electrode and the gate voltage control terminal.

Since the above electronic devices use SiC, they have excellent dielectric breakdown, can be used with high power, and have high reliability and stability even under severe conditions such as high temperature and radiation. Can be maintained.

[0061]

As described above, the present invention comprises a semiconductor having a predetermined conductivity type and an electrode formed on the semiconductor and made of a conductive oxide having the same conductivity type as the conductivity type. Therefore, there is an effect that an electrode, a SiC electrode, and a SiC device that do not require high-temperature alloy treatment and high carrier ion implantation can be obtained.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an electrode structure according to a first embodiment of the present invention.

FIG. 2 is a diagram illustrating a band structure when a conductive oxide is brought into contact with SiC.

FIG. 3 is a sectional view showing a second embodiment.

FIG. 4 is a sectional view showing a third embodiment.

FIG. 5 is a sectional view showing a fourth embodiment.

FIG. 6 is a sectional view showing a fifth embodiment.

FIG. 7 is a sectional view showing a sixth embodiment.

FIG. 8 is a sectional view showing a seventh embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 SiC (silicon carbide) 1B Source region 1C Drain region 1D n-type SiC 1Ep-type SiC 2 Conductive oxide 2A, 2B Conductive oxide film 2D Nb-doped strontium titanate 2E CuAlO ₂ 3 Metal electrode 3A, 3B Wiring connection Metal layer for 3D, 3E Contact metal film 5 Gate oxide film 8 First metal electrode (copper electrode) 9, 10 Second and third metal electrode (copper electrode)

Claims (11)

[Claims] An electrode comprising: a semiconductor having a predetermined conductivity type; and an electrode formed on the semiconductor and made of a conductive oxide having the same conductivity type as the conductivity type. 2. The electrode according to claim 1, wherein the semiconductor and the conductive oxide have substantially the same band gap. 3. An SiC electrode comprising: SiC having a predetermined conductivity type; and an electrode formed of a conductive oxide having the same conductivity type as the conductivity type formed in contact with the SiC. 4. The SiC electrode according to claim 3, wherein the electrode made of the conductive oxide has a film made of the oxide, and a metal body formed on the film. 5. The SiC electrode according to claim 1, wherein the conductive oxide is selected from the group consisting of lanthanum titanate, rhenium oxide, copper aluminum oxide, and copper gallium oxide. A certain SiC electrode. 6. The SiC electrode according to claim 1, wherein the conductive oxide is one of strontium titanate and indium oxide. 7. The SiC electrode according to claim 6, wherein the strontium titanate contains Nb,
An SiC electrode containing either Ta or La, and for the indium oxide, containing Sn as an impurity. 8. SiC using SiC as a semiconductor
A SiC device using the SiC electrode according to any one of claims 1 to 7. 9. A source and a drain provided on SiC, a gate electrode provided between the source and the drain on the SiC, and a conductive oxide provided on the source and the drain. S with electrodes
iC device. 10. An n-type SiC, a p-type SiC, and the n-type SiC.
First and second n-type conductive oxides sandwiching the p-type SiC and third and fourth n-type conductive oxides sandwiching the p-type SiC
P-type conductive oxide, a first metal electrode connecting the second conductive oxide and the fourth conductive oxide, and a second metal electrode provided for the first conductive oxide. Metal electrodes,
A third metal electrode provided for the third conductive oxide. 11. The SiC device according to claim 10, wherein between the first conductive oxide and the second metal electrode and between the second conductive oxide and the first metal electrode. ,
And ohmic characteristics with each conductive oxide between the third conductive oxide and the third metal electrode and between the fourth conductive oxide and the first metal electrode, respectively. An SiC device having a predetermined metal interposed.