JPH08316498A - Diamond semiconductor rectifying element - Google Patents

Abstract

PURPOSE: To manufacture a diamond semiconductor rectifying element so as to have rectification characteristics, such as a low forward threshold voltage and a low resistance in a forward direction. CONSTITUTION: A P-type B-doped diamond layer 1 is formed on a low-resistance silicon substrate 10 and an insulative (intrinsic) undoped diamond layer 2 having an area some larger than that of a metallic electrode 4 is made to laminate on this layer 1 by a selective growth technique. One part of a scheduled electrode lamination region on the surface of the layer 2 is oxidized and the surface of the scheduled electrode lamination region other than the oxidized one part is hydrogenerated. After that, a metal film having a low electronegativity is deposited in such a way as to lie astride the hydrogenerated and oxidized diamond layer 2 to form the metallic electrode 4. A metallic electrode/intrinsic semiconductor diamond layer/semiconductor diamond layer junction can be formed of the electrode 4 on the surface of the oxidized layer 2. The hydrogenerated diamond region on the surface of the layer 2 is formed into a P-type surface conductive layer 3 and a Schottky junction is formed of this layer 3 between the layer 3 and the electrode 4.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diamond semiconductor rectifying device such as a rectifying device and a light emitting device, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Diamond has a band gap of 5.5.
Since it has a large eV, a high dielectric breakdown electric field, and a high thermal conductivity as compared with conventional semiconductor materials, it is expected as an electronic device that can operate even under a severe environment such as high temperature and radiation. When diamond is used as an electronic device, it is important to form ohmic electrodes and rectifying electrodes on the diamond with good reproducibility. Regarding the formation of electrodes having ohmic characteristics, technical problems have already been solved by forming a high-concentration p-type semiconductor layer by ion implantation on the diamond surface. Therefore, how to form an electrode having good rectifying characteristics on diamond is a major issue.

Heretofore, a diamond rectifying device has been proposed which uses a Schottky junction between a metal electrode and a semiconductor diamond by using single crystal and polycrystalline diamond.
Many of its electrical characteristics have been reported. In the case of the Schottky junction, the forward rising voltage is as low as 1 V or less, but in order to maintain the depletion layer at the interface between the metal and the semiconductor,
The atomic B density of the semiconductor diamond layer is at least 10
It is impossible to obtain good rectifying characteristics unless the pressure is kept lower than ¹⁸ cm ^-3 . At such a doping concentration, the acceptor level of B is as large as 0.35 eV, so that the activation rate of carriers at room temperature is 0.1% or less, and only a very high resistance Schottky junction can be obtained.

In the case of the Schottky junction, the forward rising voltage is as low as about 0.5V, and the increase of the current is ex
p (qV / nkT) (where q: elementary charge, V: applied voltage, n: figure of merit of diode, k: Boltzmann constant,
(T: temperature), it exhibits a steep rising characteristic (Prior Art 1 (H.Kawarada, M.Aoki, H.Sasaki and KT
sugawa. Diamond and Related Materials 3,961 (199
Four)). However, since the resistance of the rectifying element after rising is determined by the resistance value of the semiconductor layer, if there is a constraint that a low-concentration B-doped diamond layer needs to be used, such as a Schottky junction, the resistance of the high resistance is inevitably high. Only the rectifying element can be obtained.

In order to overcome the above-mentioned drawbacks of the diamond Schottky junction, the present inventors have used a high-concentration (10 ¹⁹ cm ⁻³ or more) B-doped diamond layer as a semiconductor layer to form a thin depletion layer. We proposed a metal electrode / intrinsic semiconductor diamond / semiconductor diamond junction in which undoped insulating diamond was inserted between the metal and the semiconductor diamond layer to compensate for the thickness (Prior Art 2 (H.Shio
mi, Y.Nishibayashi and N.Fujimori, Jpn.J.Appl.Phy
s. 29, L2163 (1990), or K. Miyata, DLDreifus and
K. Kobashi, Appl. Phys. Lett. 60, 480 (1992)). In this metal electrode / intrinsic semiconductor diamond / semiconductor diamond junction, when a forward bias is applied, holes in the high-concentration B-doped diamond layer are accelerated by the electric field and injected into the undoped diamond layer to form a space-charge-limited current to form a current. Current flows, the rectifying element has a low resistance when a forward bias is applied. Further, when a reverse bias is applied, the insulating andove diamond layer forms a barrier, so that the reverse current is below the Schottky junction. In this way, a low resistance diamond rectifying device can be obtained. Fig. 1 shows the current densities of the conventional Schottky junction and metal electrode / intrinsic semiconductor / semiconductor junction in the forward direction.
It is shown in FIG. FIG. 11 shows a single crystal 6H-SiC for comparison.
The forward current density of the Schottky diode manufactured by using is also shown.

In the case of metal electrode / intrinsic semiconductor diamond / semiconductor diamond bonding, a low-resistance B-dove diamond layer can be used for the semiconductor diamond layer, so the resistance value after rising is 1/100 as compared with the Schottky junction. It is possible to

[0007]

However, as described above, by using the metal electrode / intrinsic semiconductor / semiconductor junction, a diode having low resistance in the forward direction and excellent rectification characteristics can be obtained. However, this structure has a drawback that the forward rising voltage is high. Also,
Since the electric current flows through the insulating undoped diamond layer, there is a problem that the rising voltage is greatly influenced by the crystallinity of the layer and the characteristics are varied. In particular, the carrier trap density in the insulating undoped diamond layer greatly influences the characteristics, and due to the existence of the carrier traps in the insulating undoped diamond layer, the forward rising voltage may be lower than 2.5V. Can not.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a diamond rectifying device having a rectifying characteristic in which a forward-direction rising voltage is low and a forward-direction resistance is low, and a manufacturing method thereof. To aim.

[0009]

A diamond semiconductor rectifying device according to the present invention comprises a first metal electrode and a first semiconductor diamond region having a first junction (metal electrode / semiconductor diamond junction) and a second metal electrode. It is characterized in that it has a structure in which a second junction (metal electrode / intrinsic semiconductor diamond / semiconductor diamond junction) of the intrinsic semiconductor diamond region and the second semiconductor diamond region is connected in parallel.

In this case, it is preferable that the first and second metal electrodes are formed of the same metal or the same metal. The first semiconductor diamond region is a hydrogenated p-type diamond region or a B-doped p-type diamond region, the second semiconductor diamond region is a B-dove p-type diamond region, and the intrinsic semiconductor diamond region is May be an insulating diamond region of the Andove. Further, the first and second metal electrodes can be formed of any metal selected from the group consisting of Mg, Hf, Zr and Al. Furthermore, a Pt or Au electrode can be laminated on the metal electrode as a cap layer.

In the method for manufacturing a diamond semiconductor rectifying device according to the present invention, a step of selectively growing an undoped insulating diamond layer on a B-doped p-type semiconductor diamond layer and an undoped insulating property in a region where electrodes are to be stacked are planned. A step of oxidizing a part of the surface of the diamond layer and hydrogenating the surface of the undoped insulating diamond layer in the other region, and an Andove insulating diamond region in which the metal electrode is oxidized with the hydrogenated undoped insulating diamond region And a step of forming so as to be in contact with both.

Another method of manufacturing a diamond semiconductor rectifying device according to the present invention is a step of selectively growing an undoped insulating diamond layer on a B-doped p-type semiconductor diamond layer, and an undoped region of an electrode stacking planned region. A step of synthesizing a low-concentration B-dove p-type semiconductor diamond layer having a doping concentration of 10 ¹⁸ cm ^-3 or less except for a part on the surface of the insulating diamond; And a step of forming the B-doped p-type semiconductor diamond layer so as to be in contact with both of them.

[0013]

In the present invention, by combining the low voltage rise characteristic which is the advantage of the Schottky junction and the low resistance characteristic in the forward direction which is the advantage of the metal electrode / intrinsic semiconductor diamond / semiconductor diamond junction, the rise voltage is low. In addition, an excellent diamond rectifying element having low resistance is obtained. Therefore, as described in claim 1, if two rectifying elements are connected in parallel, a current always flows through the low resistance side, so that a rising voltage is low and a low resistance diamond rectifying element can be obtained.

In the present invention, not only the Schottky diode and the metal electrode / intrinsic semiconductor diamond / semiconductor diamond junction diode are connected in parallel in a circuit manner, but the same or the same kind of electrode is provided as described in claim 2. Since the element can be manufactured in the same element by using it, the element can be downsized and the capacity can be reduced, and the diamond electronic element can be highly integrated in the future and applied to high frequencies.

Further, in the present invention, since the Schottky junction is used, considering the case where the Fermi level is not pinned, it is necessary to use a metal having a low electronegativity of 1.8 or less for the electrode. . In particular, Mg, Hf, Z
The electronegativity of r and Al is Mg: 1.2 and Hf:
Since 1.3, Zr: 1.4 and Al: 1.5 and the electronegativity is low, an excellent rectifying element can be obtained. Since a metal having a low electronegativity has a strong reactivity with oxygen, when used at a high temperature, it is preferable to stack Pt or Au as a cap layer to prevent the oxidation of the electrode in order to prevent the oxidation of the electrode.

Next, the method of the present invention for actually manufacturing the Schottky junction and the parallel connection of the metal electrode / intrinsic semiconductor diamond / semiconductor diamond junction using the same metal electrode will be described.

First, as described in claim 7, high concentration of B
A doped p-type semiconductor diamond layer is formed, and then an undoped insulating diamond layer slightly larger than the electrode area is laminated on the B-doped p-type semiconductor layer by using a selective growth technique. Then, a part of the surface of the undoped insulating diamond layer that is in contact with the electrode is oxidized, and the surface of the other undoped insulating diamond layer is hydrogenated. Then, the above-mentioned metal having a low electronegativity is vapor-deposited on the hydrogenated and oxidized undoped insulating diamond layer so that a semiconductor rectifying device can be manufactured.

That is, a metal electrode / intrinsic semiconductor diamond / semiconductor diamond junction can be produced by the metal electrode formed on the oxidized diamond surface, and the hydrogenated diamond becomes a p-type surface conduction layer, and between the metal electrode, This is because a Schottky junction is formed. That is, a parallel tangent can be realized by using the surface conduction layer on the undoped diamond surface and the conduction in the bulk.

Next, as described in claim 8, a B-doped p-type diamond layer having a doping concentration of 10 ¹⁸ cm ^-3 or less is vapor-phase synthesized in place of the above-mentioned hydrogenated p-type surface conductive layer. Thus, even if it is selectively formed on the undoped insulating diamond, the same parallel connection can be realized. Here, the reason why the doping concentration is selected to be 10 ¹⁸ cm ^-3 or less is that
This is to sufficiently expand the depletion layer in the semiconductor layer when forming the Schottky junction.

[0020]

Embodiments of the present invention will now be specifically described with reference to the accompanying drawings. FIG. 1 is a sectional view showing a semiconductor diamond rectifier according to the first embodiment of the present invention. A high-concentration B-doped p-type semiconductor diamond layer 1 is formed on a low-resistance silicon substrate 10, and then an undoped insulating property (intrinsic) slightly larger than the electrode area is formed by a selective growth technique.
The diamond layer 2 is laminated on the B-doped p-type semiconductor layer 1. Then, a part of the electrode stacking planned region on the surface of the undoped insulating diamond layer 2 is oxidized, and the other surface of the undoped insulating diamond layer is hydrogenated. Then, a metal having a low electronegativity is vapor-deposited so as to straddle over the hydrogenated and oxidized undoped insulating diamond 2 to form a metal electrode 4. Further, the ohmic electrode 5 is formed on the back surface of the low resistance silicon substrate 10 by silver paste.
To form.

Then, by the metal electrode 4 formed on the surface of the oxidized undoped insulating diamond layer 2,
A metal electrode / intrinsic semiconductor diamond / semiconductor diamond bond can be formed. On the other hand, the hydrogenated diamond on the surface of the undoped insulating diamond layer 2 has p
The surface conductive layer 3 becomes a mold, and the surface conductive layer 3 forms a Schottky junction with the metal electrode 4. This Schottky junction is derived to the ohmic electrode 5 by utilizing the carrier conduction in the surface conduction layer 3 on the surface of the undoped insulating diamond layer 2 and the bulk of the B-doped p-type diamond layer 1. Therefore, as seen from the ohmic electrode 5, a metal electrode / intrinsic diamond / semiconductor diamond junction consisting of the B-doped p-type diamond layer 1, the undoped diamond layer 2 and the metal electrode 4, and the metal electrode 4 and p
A parallel tangent line with the metal electrode / semiconductor diamond junction (Schottky junction) composed of the mold surface conduction layer 3 is obtained.
This produces a parallel junction diode of Schottky junction and metal electrode / intrinsic semiconductor diamond / semiconductor diamond.

FIG. 2 is a sectional view showing a semiconductor diamond rectifying device according to the second embodiment of the present invention. In this embodiment,
Instead of the above-mentioned hydrogenated p-type surface conductive layer 3, a B-doped p-type diamond layer 6 having a doping concentration of 10 ¹⁸ cm ⁻³ or less is selectively formed on the undoped insulating diamond layer 2 by a vapor phase synthesis method. It was formed. Even in this case, the same parallel connection can be obtained. However, the doping concentration must be 10 ¹⁸ cm ⁻³ or less. This is because the depletion layer is sufficiently expanded in the semiconductor layer when forming the Schottky junction.

Next, the result of actually manufacturing the diode according to the example of the present invention and comparing the characteristics thereof with the comparative example will be described.

Example 1 In this example, a diode having the structure shown in FIG. 1 was manufactured. A p-type low-resistivity Si (111) substrate (resistivity: 0.1 Ωcm or less, 2 cm × 1 cm) buffed with a diamond paste having an average particle diameter of ¼ μm for 1 hour was used to polycrystallize by using a microwave plasma CVD method. 2 μm of B-doped diamond thin film (B-doped p-type diamond layer 1)
Synthesized. The raw material gas used for the synthesis is methane: 0.5%,
Hydrogen: 99.5% and diborane was added as a doping gas. The B / C ratio in the gas during film formation was fixed at 400 ppm. When the atomic B density in the film was examined by secondary ion mass spectrometry, it was 1.5 × 10 ¹⁹ cm ⁻³ . The total gas flow rate, gas pressure, and substrate temperature during synthesis are 100 scc each.
m, 35 Torr, 800 ° C.

Subsequently, using a 4000 Å SiO ₂ film as a mask, an undoped diamond layer 2 (diameter: 200 μm) having a thickness of 0.4 μm is formed into a B-doped diamond layer 1.
Layered on top. Raw material gas used for synthesis is methane: 0.5
%, Hydrogen: 99.4%, oxygen: 0.1%, and the total gas flow rate, gas pressure, and substrate temperature during synthesis are the same as those during B-doped diamond layer synthesis.

Further, the SiO ₂ film used as the mask was removed with hydrofluoric acid. Thereafter, the laminated diamond layer was heated at 850 ° C. for 30 minutes in vacuum to be heat-treated, and then chromic acid + sulfuric acid mixed acid cleaning, aqua regia cleaning, and RCA cleaning were performed. This treatment has the effect of removing non-diamond components on the surface of the diamond thin film and oxidizing the surface.

Next, a part of the surface of the undoped layer was covered with photoresist and exposed to hydrogen plasma using a microwave plasma CVD apparatus. The processing condition is hydrogen: 100
%, Gas pressure: 35 Torr, hydrogen plasma treatment for 2 minutes. The substrate temperature is 780 to 800 ° C. By this treatment, the surface of the undoped diamond layer exposed to hydrogen plasma was hydrogenated, and the p-type surface conductive layer 3 was formed.
Then, the photoresist was removed with an organic solvent.

Finally, a Mg electrode 4 (diameter: 100 μm) was vapor-deposited to a thickness of 2000 Å so as to straddle the hydrogenated and oxidized Andove diamond surface by the electron beam vapor deposition method, and silver was deposited on the back surface of the Si substrate. The ohmic electrode 5 is formed by the paste, and the metal electrode / intrinsic semiconductor diamond / semiconductor diamond bonding as shown in FIG. 1 is formed.
The Schottky junction parallel connection device was completed.

Comparative Example 1 For comparison, as shown in FIG. 7, a low resistance silicon substrate 1
1, a polycrystalline B-doped diamond layer 12 is formed, and an undoped diamond layer 13, a p-type surface conduction layer 14 and a Mg electrode 15 are formed thereon. An ohmic electrode 16 made of silver paste is formed on the back surface of the substrate 11. Thus, only the surface of the Andove diamond layer 13 directly below the Mg electrode 15 is hydrogenated to form the p-type surface conduction layer 14. In this way, the diode of Comparative Example 1 was produced and its electrical characteristics were measured.

Comparative Example 2 Further, as Comparative Example 2, as shown in FIG. 8, an undoped insulating diamond thin film 22 having a thickness of 2 μm was synthesized on an insulating silicon nitride substrate 21, and then hydrogenation of the diamond surface was performed. For this purpose, hydrogen plasma treatment was performed using a microwave plasma CVD apparatus. The treatment conditions were hydrogen: 100%, gas pressure: 35 Torr, and hydrogen plasma treatment for 2 minutes. The substrate temperature is 780 to 800 ° C. Thereby, the p-type surface conductive layer 23 was formed. After that, an Mg electrode (diameter: 100 μm) was formed to be a Schottky electrode 25, and a ring-shaped Mg electrode was formed at a position of a concentric circle centered on this Schottky electrode 25 to obtain an ohmic electrode 24. As a result, a Schottky junction as shown in FIG. 8 was produced and its electrical characteristics were measured. 8A is a sectional view and FIG. 8B is a plan view.

The electrical characteristics of the devices of the example and comparative examples 1 and 2 are shown in FIGS. 3, 9 and 10, respectively. The current-voltage characteristics (in the case of Comparative Example 1) shown in FIG.
It is an intrinsic semiconductor diamond / half-body diamond junction, the forward current is as large as 5 mA when 15 V is applied, and it is a low resistance rectifying element, but the forward rising voltage is as large as 2.5 V.

The current-voltage characteristics (in the case of Comparative Example 2) shown in FIG. 10 are those of a typical Schottky junction, the forward rising voltage is as low as 1 V or less, but the resistance value of the semiconductor diamond layer is high. Therefore, when a voltage of 15 V is applied in the forward direction, the current value reaches a maximum of about 100 μA.

On the other hand, the characteristics of the device of this embodiment are shown in FIG. 3. The rising voltage in the forward direction is the same as that of the Schottky junction, which is 1 V or less, and the current value when 15 V is applied in the forward direction. It can be seen that is approximately 5 mA, which is almost the same as the current value of the metal electrode / intrinsic semiconductor diamond / semiconductor diamond junction. The forward voltage is 4-5V
In the case of, a dent can be observed in the current value, but this is due to the Schottky junction that dominated the current-voltage characteristics below 4V and the metal / intrinsic semiconductor diamond / semiconductor diamond junction that dominated the current-voltage characteristics above 5V. It is caused by the intersection of the characteristics of.

Example 2 In this example, the diode shown in FIG. 2 was manufactured. A p-type low-resistivity Si (111) substrate (resistivity: 0.1 Ωcm or less, 2 cm × 1 cm) buffed with a diamond paste having an average particle diameter of ¼ μm for 1 hour was prepared by microwave plasma CVD. A crystalline B-doped diamond thin film was synthesized to a thickness of 2 μm. The raw material gases used for the synthesis were methane: 0.5% and hydrogen: 99.5%, and diborane was added as a doping gas. During film formation, the B / C ratio in the gas was fixed at 400 ppm. As a result of examining the atomic B density in the film by secondary ion mass spectrometry, it was found to be 1.5
It was × 10 ¹⁹ cm ^-3 . The total gas flow rate, gas pressure, and substrate temperature during synthesis were 100 sccm, 35 Torr,
It was 800 ° C.

Then, an undoped diamond layer (diameter: 200 μm) having a thickness of 0.4 μm was laminated on the B-doped diamond layer using a 4000 Å SiO ₂ film as a mask. The raw material gas used for the synthesis is methane: 0.5%,
Hydrogen: 99.4%, oxygen: 0.1%, and the total gas flow rate, gas pressure, and substrate temperature during synthesis are the same as those during B-doped diamond layer synthesis. Furthermore, Si used for the mask
The O ₂ film was removed with hydrofluoric acid.

Then, using a 4000 Å SiO ₂ film as a mask, a 0.1 μm thick B-doped diamond thin film was selectively grown on the undoped diamond layer excluding the central portion. Raw material gas used for synthesis is methane: 0.5
%, Hydrogen: 99.5%, B as a doping gas
₂ H ₆ was used and the B / C ratio in the gas was set to 20 ppm. The total gas flow rate, gas pressure and substrate temperature during synthesis are the same as those during synthesis of the B-doped diamond layer. The doping concentration of B was 5 × 10 ¹⁷ cm according to secondary ion mass spectrometry.
It was ^-3 . Further, the SiO ₂ film used for the mask was removed with hydrofluoric acid.

Thereafter, the laminated diamond layers were heat-treated by heating them at 850 ° C. for 30 minutes in vacuum, followed by chromic acid + sulfuric acid mixed acid cleaning, aqua regia cleaning, and RCA cleaning.

Finally, two Mg electrodes (diameter: 100 μm) were spread by the electron beam evaporation method so as to straddle the low-concentration p-type diamond surface and the undoped diamond surface.
It was vapor-deposited to a thickness of 000Å, and an ohmic electrode was formed on the back surface of the Si substrate with silver paste. This allows
Metal electrode / intrinsic semiconductor diamond /
A semiconductor diamond junction-Schottky junction parallel connection element was completed.

The characteristics of the obtained device are shown in FIG. The forward rising voltage is the same as that of the Schottky junction and is 1 V or less, and the current value when applying 15 V in the forward direction is about 10 mA, which is almost the same as the current value of the metal electrode / intrinsic semiconductor diamond / semiconductor diamond junction. I know that Also, although a dent can be observed in the current value in the forward direction of 4 to 5 V, this is due to the Schottky junction that controlled the current-voltage characteristic at 4 V or less and the metal / intrinsic semiconductor that controls the current-voltage characteristic at 5 V or more. It is the result of the intersecting properties of the diamond / semiconductor diamond bond.

Embodiment 3 FIGS. 5 (a) and 5 (b) are a sectional view and a plan view, respectively, showing a diode rectifying device according to the third embodiment. B is 10 ¹⁹ cm ^-3
On the doped low-resistance high-pressure synthetic single crystal diamond layer 1 ((100) plane orientation, 0.3 mm thickness), 0.4 μm thick undoped diamond layer 2 (diameter: 200 μm) was homoepitaxially grown. The film forming conditions used for the synthesis were the same as in Example 1, but in order to suppress the generation of secondary nuclei, hydrogen plasma treatment was performed for 5 minutes before the film formation. After that, the laminated diamond layer is heated to 850 ° C. in vacuum for 3 hours.
A heat treatment of heating for 0 minutes was performed, and then chromic acid + sulfuric acid mixed acid cleaning, aqua regia cleaning, and RCA cleaning were performed. This treatment has the effect of removing non-diamond components on the surface of the diamond thin film and oxidizing the surface.

Next, a part (central portion) of the surface of the undoped diamond layer was covered with photoresist and exposed to hydrogen plasma using a microwave plasma CVD apparatus. The processing conditions are: hydrogen: 100%, gas pressure: 35 Torr, 2
A hydrogen plasma treatment was performed for one minute. Substrate temperature is 780-80
0 ° C. By this treatment, the peripheral portion of the surface of the undoped diamond layer exposed to the hydrogen plasma, which was not covered with the photoresist, was hydrogenated to form the p-type surface conductive layer 6. Then, the photoresist was removed with an organic solvent.

Finally, 200 Mg electrodes 4 (diameter: 100 μm) were spread over the surface of the undoped diamond layer 2 which had been hydrogenated and oxidized by electron beam evaporation.
An ohmic electrode 5 is formed by vapor deposition to a thickness of 0Å and a silver paste is formed on the back surface of the Si substrate, and a parallel connection element of metal electrode / intrinsic semiconductor diamond / semiconductor diamond junction-Schottky junction is formed as shown in FIG. Completed

FIG. 6 shows the current-voltage characteristics of the device. The rising voltage in the forward direction was as low as about 0.5 V, the current value when 15 V was applied was as high as 100 mA or more, and a rectification ratio of 9 digits or more could be obtained.

[0044]

As described above, according to the present invention,
It is possible to obtain a diamond rectifier having a low forward rising voltage and a low resistance.

[Brief description of drawings]

FIG. 1 is a sectional view showing a diamond rectifying element according to a first embodiment of the present invention.

FIG. 2 is a sectional view showing a diamond rectifying element according to a second embodiment of the present invention.

FIG. 3 is a graph showing current-voltage characteristics of the diamond rectifier of Example 1.

FIG. 4 is a graph showing the current-voltage characteristics of the diamond rectifier of Example 2.

FIG. 5 is a diagram showing an element structure of Example 3;

FIG. 6 is a graph showing the current-voltage characteristics of the diamond rectifier of Example 3.

FIG. 7 is a cross-sectional view showing a diamond rectifying element of Comparative Example 1.

8 is a diagram showing a diamond rectifying element of Comparative Example 2. FIG.

9 is a graph showing the current-voltage characteristics of the diamond rectifier of Comparative Example 1. FIG.

FIG. 10 is a graph showing current-voltage characteristics of the diamond rectifier of Comparative Example 2.

FIG. 11 is a graph showing forward current densities of various diamond rectifiers.

[Explanation of symbols]

 1: B-doped p-type diamond layer 2: Undoped diamond layer 3: p-type surface conductive layer 4: Metal electrode 5: Ohmic electrode 6: Low concentration p-type diamond layer 11: Low resistance silicon substrate 12: Polycrystalline B-doped diamond layer 13: undoped diamond layer 14: p-type surface conductive layer 15: Mg electrode 21: silicon nitrogen substrate 22: undoped diamond layer 23: p-type surface conductive layer 24: ohmic electrode 25: Schottky electrode

Claims (8)

[Claims] 1. A first junction between a first metal electrode and a first semiconductor diamond region, and a second junction between a second metal electrode, an intrinsic semiconductor diamond region and a second semiconductor diamond region are connected in parallel. A diamond semiconductor rectifying device having a structure. 2. The diamond semiconductor rectifying device according to claim 1, wherein the first and second metal electrodes are formed of the same metal or the same metal. 3. The first semiconductor diamond region is a hydrogenated p-type diamond region, the second semiconductor diamond region is a B-dove p-type diamond region, and the intrinsic semiconductor diamond region is an Andove insulating property. The diamond region is a diamond region.
Alternatively, the diamond semiconductor rectifier according to item 2. 4. The first and second semiconductor diamond regions are B-dove p-type diamond regions, and the intrinsic semiconductor diamond region is an Andove insulative diamond region. The diamond semiconductor rectifier according to 1. 5. The first and second metal electrodes are made of Mg, H
The diamond semiconductor rectifier according to any one of claims 1 to 4, wherein the diamond semiconductor rectifier is formed of any metal selected from the group consisting of f, Zr, and Al. 6. The Pt or Au electrode is laminated as a cap layer on the metal electrode.
The diamond semiconductor rectifier according to 1. 7. A step of selectively growing an undoped insulating diamond layer on a B-doped p-type semiconductor diamond layer, a step of oxidizing a part of the surface of the undoped insulating diamond layer in the electrode stacking planned region, and A step of hydrogenating the surface of the undoped insulating diamond layer in the region, and a step of forming a metal electrode in contact with both the hydrogenated undoped insulating diamond region and the oxidized andove insulating diamond region A method for manufacturing a diamond semiconductor rectifying device, comprising: 8. A step of selectively growing an undoped insulating diamond layer on a B-doped p-type semiconductor diamond layer, and a doping concentration of the undoped insulating diamond layer excluding a part of the surface of the undoped insulating diamond layer in the electrode stacking planned region. 10
A step of synthesizing a low-concentration B-dove p-type semiconductor diamond layer of ¹⁸ cm ^-3 or less, and a metal electrode being in contact with both the andove insulating diamond layer and the low-concentration B-doped p-type semiconductor diamond layer. And a step of forming the diamond semiconductor rectifying element.