JP3087831B2 - Nitride semiconductor device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an LED (light emitting diode)
Light emitting element such as LD), LD (laser diode), or
Is used in light-receiving elements such as solar cells and optical sensors.
Semiconductor (In _XAl_YGa_1-XYN, 0 ≦ X, 0 ≦ Y, X +
Y ≦ 1).

[0002]

2. Description of the Related Art Nitride semiconductors have just recently been put to practical use in full-color LED displays, traffic signals and the like as materials for high-brightness blue LEDs and pure green LEDs. These LEDs basically include an n-type clad layer composed of an n-type nitride semiconductor layer (hereinafter, referred to as an n-layer) on a sapphire substrate and a single quantum well structure (SQW: Single-Quantum).
-Well), and a p-type clad layer formed of a p-type nitride semiconductor layer (hereinafter, referred to as a p-layer).

In general, a nitride semiconductor is often grown on an insulating substrate such as sapphire.
The n-electrode and the p-electrode respectively formed on the layers are provided on the same surface side of the nitride semiconductor layer. Both electrodes provided on the same side are wire-bonded and connected to an external power supply.However, since there are multiple wire-bonding points, the probability that a wire breaks or peels off from the electrode is one place. Higher than other elements that can be wire bonded. For this reason, attempts have been made to extract an electrode from the substrate side of the nitride semiconductor device. For example, JP-A-7-221347, JP-A-8-839
29, JP-A-8-255926 describes a method of forming one electrode by making a hole in a substrate. In JP-A-8-102549 and JP-A-8-102552, an insulating film is provided on a side surface of a nitride semiconductor device, and a conductive light reflecting film is provided up to the back surface of the substrate via the insulating film. An electrode technology is described.

[0004] However, since the sapphire substrate is a very hard material, it is not very practical to form a hole in the sapphire substrate because it requires a long time and a special device. On the other hand, in the means for forming an electrode on the side surface of a semiconductor element, since the semiconductor layer has a thickness of only several μm, the efficiency of current injection is poor even if the electrode is formed in an area of several μm. In addition, since the semiconductor side surfaces must be exposed after the semiconductor layers are stacked, the surface of the semiconductor layers has more defects than the plane of the grown semiconductor layers. Therefore, there is a disadvantage that it is difficult to obtain ohmic contact between the electrode and the semiconductor layer even if the electrode is formed on the side surface. If good ohmic contact between the electrode and the semiconductor layer is not obtained, Vf (forward voltage) of the element increases, so that the calorific value increases, which adversely affects the life of the element.

Incidentally, the present applicant has recently announced a laser oscillation of 410 nm at room temperature with a pulse current using a nitride semiconductor (for example, Jpn. J. Appl. Phys. Vol. 3).
5 (1996) pp. L74-76). This laser device has a threshold current of 610 mA, a threshold current density of 8.7 kA / cm ² , and a threshold voltage of 21 V, which are considerably high in the pulse current (pulse width: 2 μs, pulse period: 2 ms). When the threshold current and the threshold voltage are reduced by improving the laser element, it is one of the very important factors to enhance the heat dissipation of the laser element for continuous oscillation.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention has been made in view of such circumstances, and an object of the present invention is to obtain an electrode having a lower contact resistance than the substrate side. It is another object of the present invention to realize a nitride semiconductor device having excellent heat dissipation.

[0007]

A nitride semiconductor device according to the present invention comprises an n-type nitride semiconductor layer, a p-type nitride semiconductor layer and a p-type nitride semiconductor layer on a first main surface of a substrate having a first main surface and a second main surface. N-type nitride semiconductor layers are stacked, and the nitride semiconductor layers on the first principal surface side are provided with an n-electrode for ohmic contact and a p-electrode, respectively. On the main surface side of
A first electrode electrically connected to one of the n and p electrodes is formed continuously with a side surface of the substrate, and the first electrode is formed on a surface of the substrate on a first main surface side. It is characterized by being insulated from the other electrode by the formed insulating film.

Further, in the device of the present invention, the n-type nitride semiconductor layer is on a side close to the first main surface, and
Are electrically connected to the n-electrode. That is, an element in which an n-layer is formed on a first main surface of a substrate and a p-layer is formed on the n-layer. An n-type ohmic electrode is provided on the surface of the n-layer. Is electrically connected to

A second electrode electrically connected to an electrode of a conductivity type opposite to the first electrode is formed on a surface of the insulating film. This second electrode comprises an n-layer and a p-layer.
It is most preferable that the layers are connected to the p-electrode in the uppermost layer of the element laminated in order from the substrate.

Further, in the device of the present invention having a second electrode which is electrically connected to the other electrode in addition to the first electrode, the second electrode is opposed to the surface of the support. It is characterized by being bonded. More preferably, the second electrode is desirably connected to a p-electrode.

[0011]

FIG. 1 is a schematic sectional view showing the structure of a nitride semiconductor device according to one embodiment of the present invention, and specifically shows the structure of a laser device. This laser device has a structure in which an n-type contact layer 2, an n-type cladding layer 3, an active layer 4, a p-type cladding layer 5, and a p-type contact layer 6 are laminated on a substrate 1. Mold clad layer 5
The p contact layer 6 and the p contact layer 6 are etched in a ridge shape in a stripe shape, and a p-electrode 11 a for ohmic contact is formed on almost the entire surface of the uppermost contact layer 6. On the other hand, on the surface of the n-type contact layer 4 exposed by etching from the p-type nitride semiconductor toward the substrate, n-electrodes 10a and 10a 'for ohmic contact are formed symmetrically with the striped p-layer. Have been. This laser element has a shape (face down) with the p-electrode 11a facing down.
For example, a conductive adhesive 3 such as Au-Ge or Au-Si
For example, it is bonded to a support 30 such as a sub-mount or a heat sink through a first mount 1.

The n-electrodes 10a and 10a 'make ohmic contact with the n-type contact layer 2, and the p-electrode 11a also makes ohmic contact with the p-type contact layer 6. As the material of the n-electrodes 10a and 10a ', for example, Al, Ti,
A material having a relatively small work function can be selected for an n-type nitride semiconductor such as W, Cu, Zn, Sn, In, and the like.
As the material of 1a, Cr, Ni, Au, Pd, Pt,
A material having a relatively large work function can be selected for a p-type nitride semiconductor such as Ti.

In this laser device, the second main surface of the substrate 1
That is, the first electrode electrically connected to the n-electrodes 10a and 10a 'is formed on the surface of the substrate on which the nitride semiconductor layer is not grown.
Electrode 10b is formed, and the first electrode 10b
Is formed continuously with the side surface of the substrate 1. Although the first electrode 10b is also in contact with the side surface of the n-type contact layer 2, the first electrode 10b is not in ohmic contact with the n-type contact layer 2, and the ohmic electrodes are only n-electrodes 10a and 10a '. And simply n-electrodes 10a, 10a
It is only electrically connected to a '. Therefore, the first
The material of the electrode 10b is not particularly limited, and a metal having conductivity and good adhesion to the n-electrodes 10a and 10a 'can be selected. For example, Al, Au, Au-Sn, Au-
A metal or alloy such as Ge and Au-Ge-Zn can be used for the first electrode 10b.

Further, the first electrode 10b is provided on the surface of the first main surface.
Due to the insulating film 20 formed on the surface, the other electrode,
It is insulated from the p-electrode 11a. The insulating film 20 is made of, for example, S
iO _Two, TiO_TwoUse insulating material such as polyimide
And normal CVD methods such as evaporation and sputtering
A thin film can be formed using a thin film growth apparatus according to the present invention. This insulating film
Reference numeral 20 denotes a short circuit between the n-electrodes 10a, a 'and the p-electrode 11a.
And protect the exposed surface of the nitride semiconductor layer.
It has a protective effect.

As described above, in the nitride semiconductor device of the present invention, since the ohmic electrode is previously formed on the surface of each nitride semiconductor layer in advance, the variation in the manufacturing process, particularly the variation due to the electrode forming process, In contrast, a very stable element can be realized. Furthermore, the first electrodes 10a and a 'formed on the second main surface side of the substrate
0 is electrically insulated from the other electrode,
A highly reliable element can be obtained.

Further, as a preferred embodiment of the present invention, a second electrode 11 electrically connected to a p-type electrode 11a of a conductivity type opposite to that of the first electrodes 10a and a 'is provided on the surface of the insulating film 20.
b is formed. The second electrode 11b is also a p-electrode 11a
It is only necessary that the electrodes be electrically connected to each other. Even if a part of the electrode is in contact with the p-layer, it is not necessary to make ohmic contact. It is highly preferable that the second electrode 11b is thus electrically connected to the p-electrode 11a of the laser element, is further insulated by the insulating film, and has a larger surface area than the p-electrode 11a. In the case of a nitride semiconductor device, an electrode is often formed on the same surface side as described above. for that reason,
To perform face-down bonding (a state in which the electrode side and the support face each other), it is necessary to increase the chip size by separating the electrodes to prevent a short circuit between the electrodes. However, the short circuit between the electrodes is prevented by the insulating film as in the present invention, and one electrode is extended to the back surface of the substrate, and one electrode is die-bonded to the support using a conductive adhesive. The other electrode has a shape that allows wire bonding. That is, the bonding shape can be the same as that of a normal semiconductor element.

Further, as shown in this figure, the element is bonded such that the second electrode 11b faces the surface of the support 30. Thus, the p-electrode 11a
Since the electrode area is increased by the second electrode 11b, bonding can be performed with the p electrode 11a facing down. In the case of a laser device, the layer that oscillates is an active layer. Comparing the distance from the active layer to the substrate and the distance from the active layer to the p-electrode, the p-electrode is overwhelmingly shorter. p electrode 11
When bonding is performed with a lower, the distance from the active layer is short, so that heat can be quickly transmitted to the support, so that heat radiation is improved and the life of the laser element is extended. Moreover, since the second electrode 11b connected to the p-electrode 11a has a larger surface area than the p-electrode 11a,
Heat can be efficiently released to the support.

FIG. 2 is a schematic sectional view showing the structure of a nitride semiconductor device according to another embodiment of the present invention, and specifically shows the structure of an LED device. Basically, the same reference numerals as those in FIG. 1 indicate the same members. This LED element also has an n-type contact layer 2 (in this element, the n-type contact layer also functions as a cladding layer for confining carriers), an active layer 4, a p-type cladding layer 5, and p on the substrate 1. Mold contact layer 6 is laminated in order,
P-electrode 1 for ohmic contact on top contact layer 6
1a, and a diffusion electrode 11c having a light-transmitting property for ohmic contact for diffusing the current of the p-electrode 11a over the entire surface of the p-layer. The diffusion electrode 11c has an action of making ohmic contact with the p-type contact layer 6 and transmitting light emitted from the active layer. On the other hand, an n-electrode 10a for ohmic contact is formed on the surface of the n-type contact layer 4 which is exposed by being etched from the p-layer toward the substrate. In this LED element, the side surface side of the element is the light emission observation surface side, and the first electrode 10 electrically connected to the n-electrode 10a.
b and the second electrode 1 electrically connected to the p-electrode 11a
1b is connected to and housed separately in a cavity of a support 30 such as a green sheet made of alumina on which an electrode pattern is formed via conductive adhesives 31 and 31 ′, respectively. Have been. In FIG. 2, the supports 30 are shown as being separate, but the supports 30 are continuous.

Similarly, in the LED element, a first electrode 10b electrically connected to the n-electrode 10a is formed on the second main surface side of the substrate 1, and the first electrode 10b is
The electrode is formed continuously from the side surface of the substrate 1 so that the electrode can be taken out from the substrate side. Moreover,
The first electrode 10b is insulated from the p-electrode 11a by an insulating film 20 formed on the surface of the first main surface.

On the surface of the insulating film 20, a p-electrode 11
Since the second electrode 11b electrically connected to the first electrode 11a is formed and the surface area of the p-electrode 11a is increased by the second electrode 11b, heat generated from the chip is efficiently transmitted to the support. Thus, the life of the LED chip can be improved. As described above, by using the element of the present invention, a side-emission observation type light-emitting device that cannot be manufactured by a conventional nitride semiconductor element can be manufactured. The edge emission observation type light emitting device can realize a high-definition display when a display is configured, for example.

[0021]

【Example】

[Embodiment 1] A method of manufacturing a laser device having a structure similar to that of FIG. 1 will be described below. A buffer layer made of B. GaN on a substrate made of A .. sapphire (C plane) C. A contact layer made of Si-doped n-type GaN D .. A crack prevention made of Si-doped n-type In0.1Ga0.9N Layer E. n-type cladding layer made of Si-doped n-type Al0.2 Ga0.8N F-type n-type light guide layer made of Si-doped GaN G. Si-doped well layer made of In0.2Ga0.8N
5 Å and Si-doped In0.01Ga0.95N
An active layer in which three pairs of barrier layers made of 50 Å are stacked and a well layer is finally stacked. A p-type cap layer made of H ·· Mg-doped p-type Al0.1Ga0.9N I ·· Mg-doped p-type GaN P-type light guide layer A p-type cladding layer made of J ·· Mg-doped p-type Al0.2Ga0.8N and a p-type contact layer made of K ·· Mg-doped p-type GaN are sequentially stacked.

A: In addition to the sapphire C surface, R
A sapphire having a main surface, A surface, or an insulating substrate such as spinel (MgA1 ₂ O ₄ ) can be used. Other SiC (including 6H, 4H, 3C), Z
Using a semiconductor substrate of nS, ZnO, GaAs, GaN, or the like, an element having a structure as in the present invention can be obtained.

B. The buffer layer is made of AlN, GaN, Al
GaN or the like can be formed at a temperature of 900 ° C. or less with a film thickness of several tens angstroms to several hundred angstroms. This buffer layer is formed in order to alleviate the lattice constant mismatch between the substrate and the nitride semiconductor, but may be omitted depending on the growth method of the nitride semiconductor, the type of the substrate, and the like.

The C..n-type contact layer is made of In _x Al _Y Ga
_1-XYN (0 ≦ X, 0 ≦ Y, X + Y ≦ 1), and especially GaN, InGaN, and especially GaN doped with Si or Ge, can provide an n-type with a high carrier concentration. A layer is obtained and a favorable ohmic contact with the n-electrode is obtained.

The D .. crack preventing layer is made of an n-type nitride semiconductor containing In, preferably InGaN, so that a thick n-type clad layer containing Al to be grown next can be grown. , Very preferred. L
In the case of D, the layer serving as the light confinement layer is preferably set to 0.
It is necessary to grow with a film thickness of 1 μm or more. Conventionally G
If a thick AlGaN is grown directly on the aN, AlGaN layer, cracks will be formed in the AlGaN grown later, making it difficult to fabricate the device. Cracks can be prevented from being contained in the n-type clad layer containing. The crack preventing layer is preferably grown to a thickness of 100 Å or more and 0.5 μm or less. When the thickness is less than 100 Å, it is difficult to function as a crack prevention as described above, and when the thickness is more than 0.5 μm, the crystal itself tends to turn black. The crack prevention layer can be omitted depending on the conditions of the growth method, the growth apparatus, and the like, but it is preferable to grow the LD when fabricating the LD. This crack preventing layer may be grown in the n-type contact layer.

The E..n-type cladding layer acts as a carrier confinement layer and a light confinement layer, and is preferably used to grow a nitride semiconductor containing Al, preferably AlGaN, and preferably 100 angstrom or more and 2 μm or less, more preferably By growing the layer with a thickness of 500 Å or more and 1 μm or less, a carrier confinement layer having good crystallinity can be formed.

The F ··· n-type light guide layer functions as a light guide layer for the active layer, and is preferably used for growing GaN or InGaN.
More preferably, it is desirable to grow with a film thickness of 200 Å to 1 μm.

The active layer includes a well layer made of a nitride semiconductor containing In and having a thickness of 70 Å or less, and a barrier layer made of a nitride semiconductor having a larger band gap energy than the well layer having a thickness of 150 Å or less. , A laser is likely to oscillate.

Although the H..p-type cap layer is p-type, the thickness is small, so that it may be i-type in which carriers are compensated by doping n-type impurities, and most preferably p-type.
The thickness of the p-type cap layer is 0.1 μm or less, more preferably 500 Å or less, and most preferably 30 Å or less.
Adjust to less than 0 angstroms. This is because if the layer is grown with a thickness greater than 0.1 μm, cracks are likely to be formed in the p-type cap layer, and a nitride semiconductor layer having good crystallinity is difficult to grow. In addition, carriers cannot pass through the energy barrier due to the tunnel effect. When the composition ratio of Al is larger and the thickness of AlGaN is smaller, the LD element is more likely to oscillate. For example, Al _Y Ga having a Y value of 0.2 or more
If it is _1- YN, it is desirable to adjust it to 500 angstroms or less. The lower limit of the thickness of the p-type cap layer 8 is not particularly limited, but is preferably formed to a thickness of 10 Å or more.

It is desirable that the I ··· p-type light guide layer be grown from GaN or InGaN, similarly to the n-type light guide layer. This layer also acts as a buffer layer when growing the p-type cladding layer, and is 100 Å to 5 Å.
μm, more preferably 200 Å to 1 μm
By growing with a film thickness of m, it functions as a preferable light guide layer.

Like the n-type cladding layer, the J..p-type cladding layer functions as a carrier confinement layer and a light confinement layer, and is a nitride semiconductor containing Al, preferably AlGa.
It is desirable to grow N, and it is possible to form a carrier confinement layer with good crystallinity by growing it at 100 Å or more and 2 μm or less, more preferably at 500 Å or more and 1 μm or less.

In the case of an active layer having a quantum structure having a well layer made of InGaN as in the embodiment, a p-type cap layer containing Al having a thickness of 0.1 μm or less is provided in contact with the active layer. A p-type light guide layer having a smaller band gap energy than the p-type cap layer is provided at a position farther from the active layer than the cap layer, and a p-type light guide is provided at a position farther from the active layer than the p-type light guide layer. P made of a nitride semiconductor containing Al having a band gap larger than that of the guide layer
It is highly preferred to provide a mold cladding layer. And p
Since the thickness of the mold cap layer is set as thin as 0.1 μm or less, it does not act as a carrier barrier,
The holes injected from the p-layer can pass through the p-type cap layer by the tunnel effect, and are efficiently recombined in the active layer, and the output of the LD is improved. That is, since the injected carriers have a large band gap energy of the p-type cap layer, the carriers do not overflow the active layer even if the temperature of the semiconductor element is increased or the injected current density is increased. Since the carrier is blocked by the cap layer, carriers are accumulated in the active layer, and light can be efficiently emitted. Therefore, even if the temperature of the semiconductor element rises, the luminous efficiency is hardly reduced, so that an LD with a low threshold current can be realized.

The K ··· p-type contact layer is a p-type In _X A
It can be composed of l _Y Ga _{1 -XYN} (0 ≦ X, 0 ≦ Y, X + Y ≦ 1), and if it is preferably GaN doped with Mg, the most preferable ohmic contact with the p electrode 11a can be obtained.

After laminating the nitride semiconductor on the substrate in the above configuration, the wafer is annealed in a nitrogen atmosphere in a reaction vessel to remove part of the hydrogen contained in the p-type cladding layer and the p-type contact layer. It is removed to further reduce the resistance of the p-type layer.

Next, RIE (reactive ion etching)
As shown in FIG. 1, the uppermost p-type contact layer and the p-type cladding layer are etched by a device to form a ridge shape having a stripe width of 4 μm. After the formation of the ridge, a mask is formed on the surface of the ridge, and the surface of the n-type contact layer is exposed symmetrically with respect to the stripe-shaped ridge as shown in FIG.

Next, an ohmic p-electrode 11a made of Ni and Au is formed in a stripe shape on the surface of the p-type contact layer at the top of the ridge. On the other hand, an ohmic n-electrode 10a made of Ti and Al is formed on almost the entire surface of the striped n-type contact layer. 80% of the total area
The above area is referred to. Annealing is performed after the electrode is formed, and the electrode and the nitride semiconductor are brought into ohmic contact.

Next, as shown in FIG. 1, an insulating film 20 made of SiO ₂ is formed on the surface of the nitride semiconductor layer exposed between the n-electrode 10a and the p-electrode 11a.
A second electrode 11b made of Au is formed to be electrically connected to the p-electrode 11a through the second electrode 11a.

As described above, the wafer on which the n-electrode and the p-electrode are formed is transferred to a polishing apparatus, and the sapphire substrate on which the nitride semiconductor is not formed is wrapped using a diamond abrasive. Has a thickness of 50 μm. After lapping, the substrate surface is mirror-finished by polishing with a finer abrasive at 1 μm.

After the substrate is polished, the polished surface side is scribed,
The wafer is cut into bars at positions symmetrical with respect to the p-electrode so that the n-electrode is formed.

After the wafer is formed into a bar shape, Au plating is performed on the sapphire substrate side and the side surfaces of the nitride semiconductor layer with the nitride semiconductor formation surface facing upward, and the back surface (second main surface) of the substrate is nitrided. The first electrode 10b is formed on the side surface of the product semiconductor in a shape as shown in FIG.

After the formation of the second electrode, the bar is cleaved in a direction perpendicular to the stripe-shaped electrodes, and a resonator is formed on the cleaved surface. Note that the cleavage plane is the M plane of the nitride semiconductor surface grown on the sapphire substrate. When the nitride semiconductor is approximated by a hexagonal system of a regular hexagonal prism, the M plane is a plane corresponding to a square plane corresponding to a side surface of the hexagonal prism. In addition, RIE
The cavity can be manufactured by etching the end face by dry etching means. In addition, it is also possible to make the cleavage plane by mirror polishing.

After the cleavage, a dielectric multilayer film composed of SiO ₂ and TiO ₂ was formed on the resonator surface, and finally the bar was cut in a direction parallel to the p-electrode to form a laser chip. Next, after bonding the chip to the heat sink with the conductive adhesive 31 made of Au / Sn face down (in a state where the second electrode 11b and the heat sink are opposed to each other), the first electrode 10b is wire-bonded. When laser oscillation was attempted at room temperature, the threshold current density was 1.
At 5 kA / cm ² and a threshold voltage of 6 V, continuous oscillation with an oscillation wavelength of 405 nm was confirmed, and continuous oscillation for one day was confirmed.

Embodiment 2 Hereinafter, an LED similar to FIG.
A method for manufacturing an element will be described. On a substrate made of sapphire, a buffer layer made of GaN, 200 Å, an n-type contact layer made of Si-doped GaN, 4 μm, an active layer of a single quantum well structure made of In0.4Ga0.6N, 30 Å, Mg-doped p-type Al
0.2 μm p-type cladding layer of 0.2 Ga 0.8 N, Mg
0.5 μm p-type contact layer made of doped p-type GaN
Are sequentially laminated.

After the lamination, annealing is similarly performed to further reduce the resistance of the p-layer, and then, as shown in FIG. 2, the n-electrode 10a is formed by etching from the side of the uppermost p-type contact layer by the RIE apparatus. The surface of the n-type contact layer to be exposed is exposed.

Next, Ni is applied to almost the entire surface of the p-type contact layer.
And ohmic translucent diffusion electrode 11c of Au and Au
Is formed with a thickness of 200 angstroms, and a p-electrode 11a is formed on the diffusion electrode 11c. On the other hand, the exposed n-type contact 3 has an n-electrode 10 made of Ti and Al.
a is formed.

After forming the electrodes, the n-electrode 10a and the p-electrode 11a
Is formed on the entire surface other than the portion exposed upward. After forming the insulating film 20, a second electrode 11b electrically connected to the p-electrode 11a is formed on the surface of the insulating film on the p-layer.

Next, the wafer is transferred to a polishing apparatus, and the sapphire substrate 1 on which the nitride semiconductor is not formed is wrapped using a diamond abrasive to reduce the thickness of the substrate to 9%.
0 μm, and scribe the sapphire substrate side to 35 μm.
A bar-shaped wafer having a width of 0 μm is obtained.

By plating the side surfaces of the bar and the sapphire substrate side with gold in the same manner as in the first embodiment, the n-electrode 10
A first electrode 10b electrically connected to the first electrode 10a is obtained.

After that, it is cut with a scriber so as to form a 350 μm square LED chip. This LED chip,
As shown in FIG. 2, in a cavity made of alumina of 500 μm square, it was connected via solder in a state where light emission could be observed from the side of the chip, and a forward current (If) was 20 m.
A, Vf was 3.4 V, emission at a light emission wavelength of 520 nm was exhibited, and the lifetime was improved by 1.5 times or more as compared with a conventional electrode provided on the same surface side.

[0050]

As described above, the device according to the present invention has the first electrode and the second electrode electrically connected to the ohmic n-electrode and the p-electrode and insulated from each other. ing. Since the ohmic in the device is obtained in advance by the n-electrode and the p-electrode, a device stable in current characteristics can be obtained. In addition, since the electrode can be taken out from the substrate side, it can be applied to any light emitting device. In addition, when applied to a device that requires heat dissipation, such as a laser element, an element with good heat dissipation can be obtained if the second electrode on the p-electrode side is in contact with the heat sink because the second electrode has good heat dissipation. Long life.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one structure of a nitride semiconductor device according to one embodiment of the present invention.

FIG. 2 is a schematic sectional view showing one structure of a nitride semiconductor device according to another embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Substrate 2 ... n-type contact layer 3 ... n-type cladding layer 4 ... Active layer 5 ... p-type cladding layer 6 ... p-type contact layer 10a, 10a '... n-electrode 10b first electrode 11a p-electrode 11b second electrode 31 conductive adhesive 30 support

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) H01L 33/00 H01L 31/10 H01S 5/00-5/50

Claims (4)

(57) [Claims] An n-type nitride semiconductor layer and a p-type nitride semiconductor layer are laminated on a first main surface side of a substrate having a first main surface and a second main surface, and the first Each of those nitride semiconductor layers on the main surface side has an n-electrode for ohmic contact,
A p-electrode is provided, and a first electrode, which is electrically connected to one of the n and p electrodes, is continuous with a side surface of the substrate on the second main surface side of the substrate. And a first electrode is insulated from the other electrode by an insulating film formed on a surface of the substrate on the first main surface side. 2. The semiconductor device according to claim 1, wherein the n-type nitride semiconductor layer is on a side close to a first main surface, and the first electrode is electrically connected to the n-electrode. The nitride semiconductor device as described in the above. 3. The device according to claim 1, wherein a second electrode electrically connected to an electrode of a conductivity type opposite to the first electrode is formed on a surface of the insulating film. 3. The nitride semiconductor device according to item 1. 4. The nitride semiconductor device according to claim 3, wherein said second electrode is bonded so as to face a support surface.