JP2002232006A - Nitride semiconductor element, and its manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enlarge the area of pn junction interface by preventing the short circuit between an n-electrode and a p-type nitride semiconductor layer and reducing the area of occupation of the n-electrode, in a pn junction type nitride semiconductor element made on an insulating substrate. SOLUTION: In the nitride semiconductor element which has an n-type nitride semiconductor layer 12, a p-type nitride semiconductor layer 14 made on the above n-type nitride semiconductor layer 12, p-electrodes 16 and 18 made on the p-type nitride semiconductor layer 14, an n-electrode 22 made on the n-type nitride semiconductor layer 12 being exposed by removing one part of the p-type nitride semiconductor layer 14, and an insulating film 20 covering the p-type nitride semiconductor layer 14 and the n-type nitride semiconductor layer 12, the n-electrode 22 is connected to the n-type nitride semiconductor layer 12 through an opening 20b which is provided in the insulating film, being made from above the insulating film 20, and the n-type nitride semiconductor layer 12 at the section to connect with the n-electrode 22 is removed partially.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a nitride semiconductor (I).
_{n x Al y Ga 1-x} -y N, 0 ≦ x ≦ 1,0 ≦ y ≦ 1,
More particularly, the present invention relates to a structure of an n-electrode in a nitride semiconductor device having an n-electrode and a p-electrode on the same surface side of a substrate.

[0002]

2. Description of the Related Art An example of a conventional nitride semiconductor device is shown in FIG.
(Plan view) and FIG. 6 (sectional view taken along line aa ′ in FIG. 5). An n-type nitride semiconductor layer 1 is formed on a sapphire substrate 10.
2 is grown, and a p-type nitride semiconductor layer 14 is grown on the n-type nitride semiconductor layer 12. Since the sapphire substrate 10 is insulative, it is necessary to contact all of the n-type nitride semiconductor layer 12 and the p-type nitride semiconductor layer 14 from above the sapphire substrate 10. Then p
Part of the nitride semiconductor layer 14 is removed by etching to expose the n-type nitride semiconductor layer 12 on the upper side of the substrate. On the surface of the p-type nitride semiconductor layer 14, a light-transmitting first p-electrode 16 that can be in ohmic contact with the p-type layer 14 is formed, and a second p-electrode 18 for making an external electrical connection is formed thereon. Have been. On the exposed surface of the n-type nitride semiconductor layer 12, an n-electrode 22 in ohmic contact with the n-type layer 12 is formed. In order to prevent a short circuit between the n-electrode 22 and the p-type nitride semiconductor layer 14, the p-type nitride semiconductor layer 1
4 is removed in a larger area than the n-electrode 22 so that a sufficient space is provided between the n-electrode 22 and the end face of the p-type nitride semiconductor layer 14.

In order to protect the n-type nitride semiconductor layer 12 and the p-type nitride semiconductor layer 14, the element surface is covered with a light-transmitting insulating film 20. The insulating film 20 is
Openings 20 a and 20 are formed on p-electrode 18 and n-electrode 22.
b, and wire bonding is performed on the second p-electrode 18 and the n-electrode 22 exposed from the openings 20a and 20b.

[0004]

However, in the above-mentioned conventional nitride semiconductor light emitting device, when the device is miniaturized, the pn junction interface (the n-type nitride semiconductor layer 12 and the p-type nitride There is a problem that the area of the bonding interface with the semiconductor layer 14) is reduced. For example, when the nitride semiconductor element is a light emitting diode, the pn junction interface is a light emitting region, so that if the area of the pn junction interface is small, sufficient light emission intensity cannot be obtained.

In order to perform wire bonding to the n-electrode 22, the wire-bonding portion of the n-electrode 22 needs to be at least about 50 μm in diameter regardless of the size of the element. However, in the conventional structure, the n-electrode 2
2 is formed in the same layer as the p-type nitride semiconductor layer 14, and if the distance from the n-electrode 22 to the end face of the p-type nitride semiconductor layer 14 is not sufficiently large, there is a possibility that both may be short-circuited. The nitride semiconductor layer 14 needs to be removed over a wide area including the n-electrode 22. For this reason, when the element is miniaturized, the area of the pn junction interface is relatively reduced.

The size of the wire bonding portion of the n-electrode 22 is determined by the opening 20b. However, even if the positions and sizes of the n-electrode 22 and the opening 20b vary within a certain patterning accuracy, the n-type is used. In order to prevent the nitride semiconductor layer 22 from being exposed, the n-electrode 22 needs to be designed larger than the opening 20b by the patterning accuracy. For this reason, it is necessary to form the n-electrode 22 larger than the minimum area required for wire bonding by the patterning accuracy, and the area of the pn junction interface has been reduced accordingly.

Therefore, the present invention prevents a short circuit between the n-electrode 22 and the p-type nitride semiconductor layer, and reduces the area occupied by the n-electrode 22, thereby increasing the area of the pn junction interface. It is an object of the present invention to provide a semiconductor device.

[0008]

In order to solve the above problems, a nitride semiconductor light emitting device according to the present invention comprises an n-type nitride semiconductor layer formed on a substrate and an n-type nitride semiconductor layer formed on the n-type nitride semiconductor layer. Formed on the p-type nitride semiconductor layer, a p-electrode formed on the p-type nitride semiconductor layer, and formed on the n-type nitride semiconductor layer exposed by removing a part of the p-type nitride semiconductor layer The n-electrode, and an insulating film covering the p-type nitride semiconductor layer and the n-type nitride semiconductor layer, wherein the n-electrode is formed on the insulating film, It is connected to the n-type nitride semiconductor layer through an opening provided in the film, and the n-type nitride semiconductor layer at a portion connected to the n-electrode has a shape partially removed. It is characterized by being.

A first feature of the present invention resides in that an n-electrode is formed on an insulating film and is connected to an n-type nitride semiconductor layer through an opening provided in the insulating film. ,
Thereby, it is possible to prevent the occurrence of a short circuit between the n-electrode and the p-type nitride semiconductor layer and reduce the area occupied by the n-electrode. That is, since the insulating film is formed between the n-electrode and the p-type nitride semiconductor layer, there is no danger of short-circuiting even if the n-electrode and the p-type nitride semiconductor layer are close to each other. Also, since the n-electrode is formed on the insulating film, the portion available for wire bonding is not limited by the opening area of the insulating film, and the n-electrode itself has a diameter of about 50 μm or more required for wire bonding. It will be good if you secure it.
Therefore, the area for removing the p-type nitride semiconductor layer can be reduced as compared with the conventional case, and the area of the pn junction interface can be increased to increase the light emission efficiency.

However, if the n-electrode is simply formed on the insulating film, the forward drive voltage increases by about 1.3 to 1.5 times. This is because the n-type nitride semiconductor layer under the insulating film is damaged when an insulating film is formed in the n-type nitride semiconductor layer and an opening is formed in the insulating film. Damaged n
The n-electrode cannot make good ohmic contact with the type nitride semiconductor layer. Therefore, the second aspect of the present invention
Is characterized in that the portion of the n-type nitride semiconductor layer connected to the n-electrode has a partially removed shape, for example, a concave or notched shape. This removes the damaged portion of the n-type nitride semiconductor layer when forming the opening in the insulating film, thereby improving the ohmic contact between the n-electrode and the n-type nitride semiconductor layer. In addition, since the n-type nitride semiconductor layer is concave or stepped, the starting point of the current flowing in the n-type nitride semiconductor layer is at a deeper position, and the contact area between the n-electrode and the n-type nitride semiconductor layer is increased. Therefore, the uniformity of the current distribution from the p electrode to the n electrode is improved.

It is preferable that the size of the portion from which the n-type nitride semiconductor layer is removed is smaller than that of the n-type electrode. The diameter of the n-electrode required for wire bonding is at least 50 μm or more, generally about 70-100 μm. The depth of the portion where the n-type nitride semiconductor layer is removed is preferably set to 500 to 10000 ° when flatness during wire bonding is important. n
This is because the step of the n-electrode increases as the type nitride semiconductor layer is removed deeper. On the other hand, when uniformity of current is important, it is preferable to remove the n-type nitride semiconductor layer as deeply as possible. For example, the depth may be such that the substrate is exposed.

In order to increase the light emitting area as much as possible, it is preferable to remove the n-type nitride semiconductor layer up to its end face. By removing the n-type nitride semiconductor layer to the end face, that is, by forming the n-electrode at the end of the n-type nitride semiconductor layer, the area for removing the p-type nitride semiconductor layer can be minimized. . Furthermore, when the n-type nitride semiconductor is formed so as to surround the periphery of the chip when excluding the end face, the uniformity of the light emission distribution can be improved. The material of the insulating film is not particularly limited, but is preferably, for example, SiO ₂ or SiN.

[0013] In a method of manufacturing a nitride semiconductor device according to the present invention, an n-type nitride semiconductor layer and a p-type nitride semiconductor layer are stacked on a substrate, and a part of the p-type nitride semiconductor layer is removed. Exposing the n-type nitride semiconductor layer, forming an insulating film on the n-type nitride semiconductor layer and the p-type nitride semiconductor layer, and forming an opening in the insulating film in a region covering the n-type nitride semiconductor layer; Forming a portion, etching away part of the n-type nitride semiconductor in the opening, and forming the n-electrode on the n-type nitride semiconductor layer from above the insulating film via the opening. It is characterized by the following. Thereby, the n-type nitride semiconductor layer damaged by the formation and removal of the insulating film can be removed, and the ohmic contact between the n-electrode and the n-type nitride semiconductor layer can be improved.

The insulating film is etched by CF ₄ , CH
Dry etching using a gas containing at least one selected from the group consisting of F ₃ and SF ₆ ,
The n-type nitride semiconductor is etched by Cl ₂ or SiCl
₄ is preferably performed by dry etching using a gas containing at least one of the above. By using such a combination of etching gases, the insulating film can be etched with high efficiency and can be etched without damaging the n-type nitride semiconductor layer.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a sectional view showing an example of a pn junction type nitride semiconductor device according to the first embodiment of the present invention. Here, a pn junction type nitride semiconductor light emitting diode will be described as an example. Sapphire substrate 1
0, GaN or Al _x Ga _1-x N (0 ≦ x <
Via low-temperature growth buffer layer made of 1) (not shown), n-type nitride semiconductor layer _(an In x _Al y Ga
_1−xy N, 0 ≦ x <1, 0 ≦ y <1, 0 ≦ x + y <
1) 12 is formed, and a p-type nitride semiconductor layer (I
_{n x Al y Ga 1-x} -y N, 0 ≦ x <1,0 ≦ y <1,
0 ≦ x + y <1) 14 is formed. A part of the p-type nitride semiconductor layer 14 is cut away to form the n-type nitride semiconductor layer 12.
Is exposed.

A light-transmitting first p-electrode 16 made of a metal thin film is formed on almost the entire surface of the p-type nitride semiconductor layer 14, and is formed diagonally with a notch for exposing the n-type nitride semiconductor layer. A second p-electrode 18 for wire bonding is formed at a corner of the first p-electrode 16 at the position where the first p-electrode 16 is formed. An insulating film 20 is formed on the entire surface of the device, and openings 20a and 20b are formed on the second p-electrode 18 and on the exposed n-type nitride semiconductor layer 12. N-type nitride semiconductor layer 1 under opening 20b
Numeral 2 has a concave shape partially removed at a depth of about 500 to 10000 °, the n-electrode 22 is formed over the opening 20b to have a larger area than the opening 20b, and the concave 12a of the n-type nitride semiconductor layer is formed. Is buried.

Since the entire surface of the n-electrode 22 can be used for wire bonding, it may be formed with a minimum diameter (for example, a diameter of about 50 μm) necessary for wire bonding. Since the n-electrode 22 and the p-type nitride semiconductor layer 14 are separated by the insulating film 20,
They can be provided close to each other. Therefore, the area from which the p-type nitride semiconductor layer 14 is removed may be smaller than before, and for example, may be substantially equal to the area required for wire bonding of the n-electrode. That is, the area of the pn junction interface, which becomes the light emitting region, can be increased as compared with the related art.

FIGS. 2A to 2D are flowcharts showing a method of manufacturing the nitride semiconductor device shown in FIG.
It should be noted that a manufacturing method similar to that of a general nitride semiconductor light emitting diode can be used except for a step related to formation of an n-electrode. First, as shown in FIG. 2 (a), on a sapphire substrate 10, GaN or _{Al x Ga 1-x N (} 0 ≦ x
<Through the low-temperature growth buffer layer made of 1) (not shown), n-type nitride semiconductor layer _(an In x _Al y Ga
_1−xy N, 0 ≦ x <1, 0 ≦ y <1, 0 ≦ x + y <
1) 12, and a p-type nitride semiconductor layer _(In x _Al y Ga
_1−xy N, 0 ≦ x <1, 0 ≦ y <1, 0 ≦ x + y <
1) Form 14. The n-type nitride semiconductor layer 12 and the p-type nitride semiconductor layer 14 can be grown, for example, by MOCVD. Then, a part of the p-type nitride semiconductor layer 14 and a part of the n-type nitride semiconductor layer 12 are etched by using a reactive ion etching method (hereinafter, RIE method) to expose the n-type nitride semiconductor layer 12. . A translucent first p-electrode 16 made of a metal thin film of Ni / Au or the like is formed on almost the entire surface of the p-type nitride semiconductor layer 14, and a notch for exposing the n-type nitride semiconductor layer and a diagonal line to each other. The second p-electrode 18 for wire bonding made of a metal such as Au is formed at the corner of the first p-electrode 16 at the position where the first p-electrode 16 is formed. Then, on the second p-electrode 18 (= opening 20)
An insulating film 20 such as SiO ₂ or SiN is formed on the entire surface of the device except for the portion (a).

Next, as shown in FIG. 2B, an opening 20b is formed in a portion of the insulating film 20 covering the n-type nitride semiconductor layer 12.
To form The opening 20b is formed by CF ₄ , CH
It is preferable to perform dry etching using a fluorine-based gas containing F ₃ , SF _6, or the like. The insulating film 2 is formed on the surface of the n-type nitride semiconductor layer 12 exposed in the opening 20b.
Since the damage due to the formation of 0 and etching removal remains, if the n-electrode 22 is formed as it is, the n-electrode 22
Then, the contact resistance of the n-type nitride semiconductor layer 12 increases, and the forward drive voltage increases by about 1.5 times. In addition, if the n-type nitride semiconductor layer is etched by wet etching using hydrofluoric acid, damage to the n-type nitride semiconductor layer 12 can be reduced. Since the damage caused by the method remains, the forward driving voltage is increased about 1.3 times as compared with the conventional method.

Then, as shown in FIG. 2C, the n-type nitride semiconductor layer 12 exposed in the opening 20b is removed by etching to form a recess 12a. etching the n-type nitride semiconductor layer 12, a p-type nitride semiconductor layer 14 and the n-type nitride semiconductor layer under the same conditions as in the case of etching in FIG. 2 (a), the words, Cl ₂ and SiCl
It is preferable to carry out the RIE method using a gas containing ₄ . By using these etching methods, the n-type nitride semiconductor layer 12 damaged by the formation and etching of the insulating film 20 is removed, and a relatively good crystalline state of the n-type nitride semiconductor surface is exposed. Can be.

With respect to the etching depth of the n-type nitride semiconductor layer, the deeper the etching is, the more advantageous in removing the damage, and the deeper the starting point of the current flowing through the n-type nitride semiconductor layer is, The contact area between the n-type nitride semiconductor layer and the n-type nitride semiconductor layer can be increased, and the uniformity of the current flowing through the n-type nitride semiconductor layer can be improved. On the other hand, if the etching is too deep, a large step will be formed on the surface of the n-electrode 22 to be formed later, making wire bonding difficult. Therefore, when performing wire bonding, it is preferable that the etching depth is 500 to 10000 °.
In the case where a connection using a conductive paste is performed instead of the wire bonding, deeper etching can be performed.

Next, as shown in FIG.
An n-electrode 22 made of a metal or the like containing W and Al is formed from above the opening 20b with a larger area than the opening 20b, and is connected to the n-type nitride semiconductor layer 12 in the recess 12a. The n-electrode 22 is preferably formed in a thick film so as to fill the concave portion 12a and become flat.

Embodiment 2 FIG. FIG. 3 is a sectional view showing a nitride semiconductor device according to the second embodiment of the present invention. In the present embodiment, etching of n-type nitride semiconductor layer 12 is performed until sapphire substrate 10 is exposed, thereby forming concave portion 1.
2a is formed. Other points are the same as in the first embodiment. According to the present embodiment, since n-electrode 22 is formed to a deeper position, the distribution of current flowing from p-electrode 16 to n-electrode 22 is increased in the thickness direction of n-type nitride semiconductor layer 12. And more uniform light emission can be obtained. Further, since the etching of the n-type nitride semiconductor layer 12 is stopped by the sapphire substrate 10, the control of the etching depth becomes easy, and the variation in the element performance can be suppressed.

In the present embodiment, since the concave portion 12a is deep, the n-electrode 22 cannot sufficiently flatten the concave portion 12a, and a large step is formed in the n-electrode 22. For this reason, it is preferable that the lead connection to the n-electrode 22 be performed using a conductive paste rather than wire bonding.
This is because it is difficult to perform wire bonding on an electrode having a step, while a conductive paste can be adhered along the step of the electrode.

Embodiment 3 FIG. 4 is a sectional view showing a nitride semiconductor device according to the third embodiment of the present invention. In the present embodiment, an opening 20b is formed by cutting out a part of the end of the insulating film 20, and the n-type nitride semiconductor layer 12 is etched by etching the n-type nitride semiconductor layer 12 to the end face. A notch 12c is formed. Then, the n-electrode 22 is cut into the notch 1 of the n-type nitride semiconductor layer.
2c. Other points are described in the second embodiment.
Is the same as

According to the present embodiment, n
Since the electrode 22 can be formed, the area of the pn junction interface can be further increased. Note that, also in the present embodiment, it is preferable that the lead connection to the n-electrode 22 be performed using a conductive paste rather than wire bonding.

In the first to third embodiments, a simple pn junction type nitride semiconductor light emitting diode composed of two layers of an n type nitride semiconductor layer and a p type nitride semiconductor layer has been described as an example. As long as the device includes an n-type nitride semiconductor layer and a p-type nitride semiconductor layer and has a structure in which an electrode is taken from the upper surface of each layer, the present invention can be applied to devices having other structures in the same manner as in the above embodiment. Can be applied. For example, it has a double hetero structure including an n-type contact layer, an n-type cladding layer, an active layer, a p-type cladding layer, and a p-type contact layer, and forms electrodes on the n-type contact layer and the p-type contact layer from the upper surface of the substrate. In the case of an element to be formed, the n-type contact layer may be handled in the same manner as the n-type nitride semiconductor layer 12 in the above embodiment.

[0028]

Embodiments of the present invention will be described below. Embodiment 1 FIG. In the present embodiment, the present invention is applied to a nitride semiconductor light emitting diode having a double hetero structure. In this example, a structure similar to that of the embodiment shown in FIGS. 1 and 2 was produced except that a simple pn junction type was changed to a double hetero type. The size of the element is about 3
The size was 50 μm square. The growth of the nitride semiconductor layers was performed by MOCVD.

(N-type contact layer) First, 2 inch φ,
After growing a buffer layer made of GaN to a thickness of 200 angstroms at 500 ° C. on a sapphire substrate 10 having a (0001) C-plane as a main surface, at 1050 ° C.
Using TMG as a source gas, ammonia gas, and silane gas as an impurity gas, an n-side contact layer made of GaN doped with 4.5 × 10 ¹⁸ / cm ^{3 of} Si is grown to a thickness of 2.25 μm.

(N-type cladding layer) Next, only silane gas was stopped, and TMG and ammonia gas were used at 1050 ° C.
An undoped GaN layer is grown to a thickness of 75 angstroms, and then a silane gas is added at the same temperature to grow a GaN layer doped with Si to 4.5 × 10 ¹⁸ / cm ³ to a thickness of 25 angstroms. Thus, 75
A pair consisting of an A layer made of an undoped GaN layer of Å and a B layer made of 25 Å having a Si doped GaN layer is grown. And 25 pairs
The layers are stacked to have a thickness of 2500 angstroms, and an n-side first clad multilayer film layer composed of a multilayer film having a superlattice structure is grown. At a similar temperature, a second undoped GaN
Then, the temperature is raised to 800 ° C., and a first nitride semiconductor layer made of undoped In _0.13 Ga _0.87 N is grown to 20 Å using TMG, TMI and ammonia. These operations are repeated so that ten layers are alternately stacked in the second + first order, and finally, a second nitride semiconductor layer made of GaN is grown on the n-side by a superlattice multilayer film grown by 40 angstroms. A second cladding multilayer is grown to a thickness of 640 Å.

(Active Layer) Next, a barrier layer made of undoped GaN is grown to a thickness of 250 Å.
Subsequently, at a temperature of 800 ° C., a well layer of undoped In _0.3 Ga _0.7 N is grown to a thickness of 30 Å using TMG, TMI, and ammonia. And barrier layers in the order of barrier + well + barrier + well...
An active layer having a multiple quantum well structure with a total thickness of 1930 Å is grown by alternately stacking six layers and six well layers.

(P-type cladding layer) Next, at a temperature of 1050 ° C.
Using TMG, TMA, ammonia, Cp ₂ Mg (cyclopentadienyl magnesium), and adding Mg to 1 × 10 ²⁰
/ Cm ³ -doped p-type Al _0.2 Ga _0.8 N third nitride semiconductor layer is grown to a thickness of 40 Å, and then at a temperature of 800 ° C., TMG, TMI, ammonia and Cp ₂ Mg are added. A fourth nitride semiconductor layer made of In _0.03 Ga _0.97 N doped with 1 × 10 ²⁰ / cm ^{3 of} Mg is grown to a thickness of 25 Å. These operations are repeated, and five layers are alternately stacked in the third + fourth order. Finally, a p-layer made of a superlattice-structured multilayer film in which a third nitride semiconductor layer is grown to a thickness of 40 angstroms. A side multilayer cladding layer is grown to a thickness of 365 Å.

(P-type contact layer) Subsequently, at 1050 ° C.
And using TMG, ammonia and Cp ₂ Mg,
A p-side contact layer made of p-type GaN doped with × 10 ²⁰ / cm ³ is grown to a thickness of 700 Å. After completion of the reaction, the temperature is lowered to room temperature, and the wafer is annealed at 700 ° C. in a reaction vessel in a nitrogen atmosphere to further reduce the resistance of the p-type layer.

(Formation of p-electrode) Next, the wafer is taken out of the reaction vessel, and a mask having a predetermined shape is formed on the surface.
Etching is performed from the p-type contact layer side with the IE device,
The surface of the n-side contact layer is exposed.

After the etching, almost all of the uppermost p-type contact layer is covered with a 200 Å-thick Ni film.
A light-transmitting first p-electrode containing Au and Au, and a second p-electrode made of Au for bonding on the first p-electrode having a thickness of 0.5 μm.
It is formed with a film thickness of μm.

(Formation of Insulating Film and N-Electrode) Next, an insulating film made of SiO ₂ is formed to a thickness of 3000 ° by sputtering so as to cover the entire surface of the substrate except for the second p-electrode. Then, the insulating film on the n-type contact layer is etched by RIE using CF ₄ to form a circular opening having a diameter of 50 μm, exposing the n-type contact layer.
Then, the exposed n-type contact is replaced with Cl ₂ and SiCl
Etching by RIE using a gas containing ₄
A recess having a depth of 4000 ° is formed in the mold contact layer. Thereafter, an n-electrode containing W and Al is formed with a diameter of 70 μm so as to cover the concave portion of the n-type contact layer and a part of the insulating film, thereby forming an LED element.

Comparative Example 1 An LED element is manufactured in the same manner as in Example 1 except that no recess is formed in the n-type contact layer. The LED element of Example 1 was able to increase the area of the pn junction interface by about 15% as compared with the conventional LED elements as shown in FIGS. Further, the LE of the first embodiment is used.
The D element has a forward drive voltage equivalent to that of the conventional LED element, and has a forward voltage of about 5 times as compared with the LED element of Comparative Example 1.
0% lower.

[0038]

According to the present invention, the short-circuit between the n-electrode and the p-type nitride semiconductor layer is prevented, and the area occupied by the n-electrode is reduced. Good ohmic contact between the semiconductor layer and the n-type nitride semiconductor layer can be maintained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of a nitride semiconductor device according to a first embodiment of the present invention.

FIG. 2 is a process chart showing a method for manufacturing the nitride semiconductor device shown in FIG.

FIG. 3 is a schematic sectional view showing an example of a nitride semiconductor device according to a second embodiment of the present invention.

FIG. 4 is a schematic cross-sectional view showing one example of a nitride semiconductor device according to a third embodiment of the present invention.

FIG. 5 is a schematic plan view showing an example of a conventional nitride semiconductor device.

FIG. 6 is a schematic cross-sectional view of the nitride semiconductor device shown in FIG.

[Explanation of symbols]

Reference Signs List 10 substrate, 12 n-type nitride semiconductor layer, 12a recess, 14 p-type nitride semiconductor layer, 16 first p electrode, 1
8 2nd p electrode, 20 insulating film, 20a and 20b opening, 22n electrode

Claims (7)

[Claims] 1. An n-type nitride semiconductor layer on a substrate, a p-type nitride semiconductor layer formed on the n-type nitride semiconductor layer, and a p-electrode formed on the p-type nitride semiconductor layer. An n-electrode formed on the n-type nitride semiconductor layer, which is exposed by removing a part of the p-type nitride semiconductor layer, and an insulation covering the p-type nitride semiconductor layer and the n-type nitride semiconductor layer Wherein the n-electrode is formed over the insulating film, and is connected to the n-type nitride semiconductor layer via an opening provided in the insulating film; A nitride semiconductor element, wherein a portion of the n-type nitride semiconductor layer connected to an n-electrode has a partially removed shape. 2. The nitride semiconductor device according to claim 1, wherein the n-type nitride semiconductor layer has a smaller area than the n-electrode and is removed to a depth of 500 to 10000 °. 3. The nitride semiconductor device according to claim 1, wherein said n-type nitride semiconductor layer is removed to a depth where said substrate is exposed. 4. The nitride semiconductor device according to claim 1, wherein said n-type nitride semiconductor layer is removed to an end face thereof. 5. The nitride semiconductor device according to claim 1, wherein said insulating film is made of SiO ₂ or SiN. 6. An n-type nitride semiconductor layer and a p-type nitride semiconductor layer are stacked on a substrate, and the n-type nitride semiconductor layer is exposed except for a part of the p-type nitride semiconductor layer, Forming an insulating film on the n-type nitride semiconductor layer and the p-type nitride semiconductor layer; forming an opening in the insulating film in a region covering the n-type nitride semiconductor layer; A method of manufacturing a nitride semiconductor device, characterized in that an n-type nitride semiconductor is partially removed by etching and an n-electrode is formed in the n-type nitride semiconductor layer from above the insulating film through the opening. . 7. The etching of the insulating film is performed by using CF ₄ , C
Dry etching is performed using a gas containing at least one selected from the group consisting of HF ₃ and SF ₆ , and the etching of the n-type nitride semiconductor is performed using a gas containing at least one of Cl ₂ or SiCl _4. 7. The method for manufacturing a nitride semiconductor device according to claim 6, wherein the method is performed by dry etching.