JP6206710B2 - Nitride semiconductor light emitting device - Google Patents

Description

  The present invention relates to a nitride semiconductor light emitting device, and more particularly to a light emitting device that emits ultraviolet light.

  Conventionally, light emitting elements using nitride semiconductors are widely used for blue light emitting diodes and the like. Recently, development of an ultraviolet light emitting diode (LED) having a shorter wavelength region, for example, an emission wavelength in a 370 nm band has been advanced (see, for example, Patent Document 1).

JP 2013-120929 A

  A light emitting element that emits ultraviolet light is used for, for example, so-called curing, in which the resin is irradiated with ultraviolet light and cured. However, ultraviolet light is a wavelength region that cannot be visually recognized by the naked eye. On the other hand, since ultraviolet light is harmful, an operator needs to attach a device such as safety glasses for blocking ultraviolet light for safety. Under such circumstances, the worker cannot visually determine whether or not the target area is correctly irradiated with ultraviolet light, and is inconvenienced.

  Accordingly, an object of the present invention is to provide a nitride semiconductor light-emitting element that can visually recognize the irradiation when irradiating a target location with ultraviolet light, and a method for manufacturing the same.

The nitride semiconductor light emitting device of the present invention is a nitride semiconductor light emitting device having a light emitting layer between an n-type nitride semiconductor layer and a p-type nitride semiconductor layer,
The main emission wavelength is ultraviolet light of 375 nm or less,
The n-type nitride semiconductor layer includes Al _n Ga _1-n N (0 ≦ n ≦ 1), and the contained C concentration is in a range exceeding 1 × 10 ¹⁷ / cm ³ .

As will be described later in the section “DETAILED DESCRIPTION OF THE INVENTION”, when the C concentration contained in the n-type nitride semiconductor layer is increased by the inventors' diligent research, the light emitting element emits a yellow visible light band. We have determined that luminescence (so-called “deep luminescence”) is strongly manifested. In particular, by setting the C concentration to a range exceeding 1 × 10 ¹⁷ / cm ³ , the ratio of deep light emission contained in the irradiated light is increased, and the brightness of the irradiated portion can be increased to a visible level. I found out.

  When a light-emitting element whose main emission wavelength is ultraviolet light is configured as a nitride semiconductor light-emitting element, the effect of purple visible light corresponding to the bottom part of the peak wavelength is originally generated by emitting ultraviolet light. In response, dark purple light is emitted. However, since this deep purple light is a very dark color, it is difficult for an operator to make a comparison with the naked eye in comparison with a state where no light is irradiated.

  On the other hand, when deep light emission including light in the yellow visible light band is generated, the emission color becomes whitish by mixing the purple light and the yellow light. For this reason, if the said light is irradiated to the target location, ultraviolet light can be irradiated, making the said irradiated location bright. Therefore, the worker can visually confirm whether or not the target portion is irradiated correctly with ultraviolet light.

  Since such an element emits ultraviolet light having a main emission wavelength of 375 nm or less, it can be used for applications such as light cleaning and photocatalysis in addition to the curing described above. When used in such applications, if the ultraviolet light that indicates the main emission wavelength is correctly irradiated to the irradiated part, even if a part of the light in the visible light band wavelength (here, deep light) is included, Can be realized. Then, by utilizing the light of the nitride semiconductor light emitting device of the present invention for the above-mentioned use, it is possible to visually confirm whether or not the irradiation is correctly performed while realizing the intended use.

In the nitride semiconductor light emitting device of the present invention, the C concentration contained in the n-type nitride semiconductor layer is more preferably 5 × 10 ¹⁷ / cm ³ or more. Thereby, an irradiation location can be further brightened and it becomes easy to visually recognize that it is irradiated.

  Another feature of the nitride semiconductor light emitting device of the present invention is that the emission intensity of yellow visible light wavelength exceeds 0.1% with respect to the emission intensity of the main emission wavelength.

In addition, the method for manufacturing the nitride semiconductor light emitting device of the present invention includes:
a step (a) of forming an n-type nitride semiconductor layer;
A step (b) of forming a light emitting layer;
And a step (c) of forming a p-type nitride semiconductor layer,
The step (a) is a step of supplying a source gas having a V / III ratio of less than 2000, which is a ratio of a flow rate of a compound containing a group V element to a flow rate of a compound containing a group III element, into a processing furnace to grow crystals. It is characterized by being.

By the above method, a nitride semiconductor light-emitting device having a C concentration in the n-type nitride semiconductor layer exceeding 1 × 10 ¹⁷ / cm ³ can be manufactured, and irradiated when ultraviolet light is irradiated to a target location. Thus, a nitride semiconductor light emitting device that can be visually confirmed is realized.

  According to the nitride semiconductor light emitting device of the present invention, in addition to ultraviolet light, which is the main light emission wavelength, light including deep light emission of a certain percentage or more of yellow visible light band is emitted. Brightness can be increased.

1 is a schematic cross-sectional view of a nitride semiconductor light emitting device. 6 is a schematic cross-sectional view of a nitride semiconductor light emitting device of Example 3. FIG. It is a graph which shows the spectral distribution of the light obtained when the same electric current is sent through five elements of Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2. It is a photograph which shows the light emission aspect when the same electric current is sent through four elements of Example 1, Example 2, Comparative Example 1, and Comparative Example 2. It is another schematic sectional drawing of the nitride semiconductor light-emitting device.

  The nitride semiconductor light emitting device of the present invention will be described with reference to the drawings. In each figure, the dimensional ratio in the drawing does not necessarily match the actual dimensional ratio.

[Construction]
The structure of the nitride semiconductor light emitting device 1 of the present invention will be described with reference to FIG. 1A. FIG. 1A is a schematic cross-sectional view of a nitride semiconductor light emitting device 1. In the present embodiment, the nitride semiconductor light emitting element 1 is described as an ultraviolet light emitting element having a main emission wavelength of 375 nm or less.

  The nitride semiconductor light emitting element 1 is formed by laminating a support substrate 2, an undoped layer 3, an n-type nitride semiconductor layer 4, a light emitting layer 5, and a p-type nitride semiconductor layer 6 in this order from the bottom.

(Support substrate 2)
The support substrate 2 is composed of a sapphire substrate. In addition to sapphire, Si, SiC, AlN, AlGaN, GaN, YAG, or the like may be used.

(Undoped layer 3)
The undoped layer 3 is formed of GaN. More specifically, it is formed of a low-temperature buffer layer 3a made of GaN and an underlying layer 3b made of GaN on the upper layer.

(N-type nitride semiconductor layer 4)
The n-type nitride semiconductor layer 4 is made of Al _n Ga _1-n N (0 ≦ n ≦ 1) formed so that the concentration of C contained as an impurity exceeds 1 × 10 ¹⁷ / cm ³ . Composed. A method for forming the n-type nitride semiconductor layer 4 containing a C concentration within this range will be described later.

(Light emitting layer 5)
The light emitting layer 5 is formed of a semiconductor layer (AlGaInN light emitting layer) having a multiple quantum well structure in which, for example, a well layer made of InGaN and a barrier layer made of AlGaN are repeated. These layers may be undoped or p-type or n-type doped.

(P-type nitride semiconductor layer 6)
The p-type nitride semiconductor layer 6 is composed of Al _m Ga _1-m N (0 <m ≦ 1). Note that, unlike the n-type nitride semiconductor layer 4, the p-type nitride semiconductor layer 6 may have a concentration of C contained as an impurity of 1 × 10 ¹⁷ / cm ³ or less.

  Although not shown in FIG. 1A, the nitride semiconductor light emitting device 1 may have a high Mg concentration p-type (Al) GaN layer for contact on the p-type nitride semiconductor layer 6. Alternatively, the n-type nitride semiconductor layer 4 exposed by etching may have an n-electrode on the upper layer and a p-electrode on the high-concentration p-type (Al) GaN layer (so-called lateral structure). Further, a metal electrode to be a p-electrode is formed on the p-type GaN layer, and a conductor or semiconductor substrate is bonded to the upper layer, and then the support substrate 2 is peeled by turning up and down to form an n-type nitride. An n-electrode may be formed on the upper layer of the semiconductor layer 4 (so-called vertical structure).

[Manufacturing process]
Next, a manufacturing process of the nitride semiconductor light emitting device 1 shown in FIG. 1A will be described. This manufacturing process is merely an example, and the gas flow rate, the furnace temperature, the furnace pressure, and the like may be appropriately adjusted.

  First, the undoped layer 3 is formed on the support substrate 2. This is realized, for example, by the following method.

(Preparation of support substrate 2)
A sapphire substrate is prepared as the support substrate 2, and the c-plane sapphire substrate is cleaned. More specifically, for this cleaning, for example, a c-plane sapphire substrate is placed in a processing furnace of a MOCVD (Metal Organic Chemical Vapor Deposition) apparatus, and hydrogen gas with a flow rate of 10 slm is placed in the processing furnace. The temperature in the furnace is raised to, for example, 1150 ° C. while flowing.

(Formation of undoped layer 3)
Next, a low-temperature buffer layer made of GaN is formed on the surface of the c-plane sapphire substrate, and an underlayer made of GaN is further formed thereon. These low-temperature buffer layer and underlayer correspond to the undoped layer 3.

  A more specific method for forming the undoped layer 3 is, for example, as follows. First, the furnace pressure of the МОCVD apparatus is 100 kPa, and the furnace temperature is 480 ° C. Then, while flowing nitrogen gas and hydrogen gas with a flow rate of 5 slm respectively as carrier gases into the processing furnace, trimethylgallium (TMG) with a flow rate of 50 μmol / min and ammonia with a flow rate of 223000 μmol / min are used as the source gas in the processing furnace. For 68 seconds. Thereby, a low-temperature buffer layer made of GaN having a thickness of 20 nm is formed on the surface of the c-plane sapphire substrate.

  Next, the furnace temperature of the MOCVD apparatus is raised to 1150 ° C. Then, while flowing nitrogen gas having a flow rate of 20 slm and hydrogen gas having a flow rate of 15 slm as a carrier gas in the processing furnace, TMG having a flow rate of 100 μmol / min and ammonia having a flow rate of 223000 μmol / min are introduced into the processing furnace as source gases. Feed for 30 minutes. As a result, a base layer made of GaN having a thickness of 1.7 μm is formed on the surface of the low-temperature buffer layer.

(Formation of n-type nitride semiconductor layer 4)
Next, an n-type nitride semiconductor layer 4 having a composition of Al _n Ga _1-n N (0 ≦ n ≦ 1) is formed on the undoped layer 3.

A more specific method for forming the n-type nitride semiconductor layer 4 is, for example, as follows. First, with the furnace temperature kept at 1150 ° C., the furnace pressure of the MOCVD apparatus is set to 30 kPa. Tetraethylsilane for doping TMG, trimethylaluminum (TMA), ammonia, and n-type impurities as source gases while flowing nitrogen gas having a flow rate of 20 slm and hydrogen gas having a flow rate of 15 slm as a carrier gas in the processing furnace. Is fed into the processing furnace for 30 minutes. Thereby, for example, an n-type nitride semiconductor layer 4 having a composition of Al _0.06 Ga _0.94 N and a thickness of 1.7 μm is formed in the upper layer of the undoped layer 3.

Here, the flow rate ratio (V / III ratio) between the V group ammonia and the III group TMG and TMA is less than 2000, so that the C concentration contained in the n-type nitride semiconductor layer 4 is 1 × 10 6. It can be higher than ¹⁷ / cm ³ . For example, by using TMG with a flow rate of 100 μmol / min, TMA with a flow rate of 5.2 μmol / min, and ammonia with a flow rate of 116000 μmol / min as the source gas, the V / III ratio can be about 1000. Tetraethylsilane also contains C atoms, but its flow rate is, for example, about 0.025 μmol / min, so the influence on the C concentration contained in the n-type nitride semiconductor layer 4 is negligible compared to TMG and TMA. it can.

When the V / III ratio was about 1000 and the furnace pressure was 10 kPa, the content C concentration of the generated n-type nitride semiconductor layer 4 was 1 × 10 ¹⁸ / cm ³ (Example 1 described later) ). Further, when the pressure in the furnace is 30 kPa, the concentration of contained C when the V / III ratio is 1000 is 5 × 10 ¹⁷ / cm ³ (Example 2 described later), and the V / III ratio is The content C concentration when 2000 is 1 × 10 ¹⁷ / cm ³ (Comparative Example 1 described later), and the content C concentration when the V / III ratio is 4000 is 5 × 10 ¹⁶ / cm 3. ³ (Comparative Example 2 described later). The content C concentration of the generated n-type nitride semiconductor layer 4 was measured by SIMS (Secondary Ion Mass Spectrometry).

  CMG is contained in the constituent molecules of TMG and TMA, which are source gases. On the other hand, ammonia does not contain C atoms. For this reason, the content C density | concentration of the n-type nitride semiconductor layer 4 formed can be raised by making V / III ratio low. Moreover, the amount of C uptake increases by changing from GaN to AlGaN. Since Al has a strong binding energy, the amount of C and O contained in the raw material can be increased more easily than Ga. That is, by configuring the n-type nitride semiconductor layer 4 with AlGaN, the C concentration of the n-type nitride semiconductor layer can be increased as compared with the case of configuring with n-type nitride semiconductor layer 4.

  In addition to lowering the V / III ratio, it is possible to increase the concentration of contained C by lowering the growth pressure. This is because by lowering the growth pressure, the time during which ammonia stays in the MOCVD apparatus is reduced, the inside of the furnace becomes a Group III rich environment, and the same effect as lowering the V / III ratio can be obtained. This is probably because of this. In this case, the growth pressure is preferably 10 kPa or more and 100 kPa or less, and more preferably 10 kPa or more and 50 kPa or less.

  In the above-described embodiment, the case where Si is used as the n-type impurity contained in the n-type nitride semiconductor layer 4 is described. However, Ge, S, Se, Sn, Te, or the like can be used in addition to Si. it can.

(Formation of the light emitting layer 5)
Next, the light emitting layer 5 having a multiple quantum well structure made of AlGaInN is formed on the n-type nitride semiconductor layer 4.

  Specifically, first, the furnace pressure of the MOCVD apparatus is set to 100 kPa, and the furnace temperature is set to 830 ° C. Then, while flowing nitrogen gas having a flow rate of 15 slm and hydrogen gas having a flow rate of 1 slm as a carrier gas in the processing furnace, TMG having a flow rate of 10 μmol / min, trimethylindium (TMI) having a flow rate of 12 μmol / min, and A step of supplying ammonia at a flow rate of 300,000 μmol / min into the processing furnace for 48 seconds is performed. Thereafter, TMG having a flow rate of 10 μmol / min, TMA having a flow rate of 1.6 μmol / min, tetraethylsilane having a flow rate of 0.002 μmol / min, and ammonia having a flow rate of 300,000 μmol / min are supplied into the processing furnace for 120 seconds. Hereinafter, by repeating these two steps, the light emitting layer 5 having a 15-cycle multiple quantum well structure composed of a well layer made of InGaN having a thickness of 2 nm and a barrier layer made of n-type AlGaN having a thickness of 7 nm is obtained as an n-type. It is formed on the surface of nitride semiconductor layer 4.

(Formation of p-type nitride semiconductor layer 6)
Next, a p-type semiconductor layer 6 composed of Al _m Ga _1-m N (0 ≦ m <1) is formed on the light emitting layer 5.

Specifically, the furnace pressure of the MOCVD apparatus is maintained at 100 kPa, and the furnace temperature is raised to 1025 ° C. while nitrogen gas having a flow rate of 15 slm and hydrogen gas having a flow rate of 25 slm are supplied as carrier gases in the processing furnace. To do. Thereafter, as source gases, TMG with a flow rate of 35 μmol / min, TMA with a flow rate of 20 μmol / min, ammonia with a flow rate of 250,000 μmol / min, and biscyclopentadiene with a flow rate of 0.1 μmol / min for doping p-type impurities. Enilmagnesium (Cp ₂ Mg) is fed into the processing furnace for 60 seconds. Thereby, a hole supply layer having a composition of Al _0.3 Ga _0.7 N having a thickness of 20 nm is formed on the surface of the light emitting layer 5. Thereafter, with the TMG flow rate kept at 35 μmol / min, the TMA flow rate was changed to 4 μmol / min and the raw material gas was supplied for 360 seconds, whereby the composition of Al _0.1 Ga _0.9 N having a thickness of 120 nm was obtained. Forming a hole supply layer. A p-type nitride semiconductor layer 6 is formed by these hole supply layers.

  Here, in the formation process of the p-type nitride semiconductor layer 6, film growth is performed at a lower temperature than in the formation process of the n-type nitride semiconductor layer 4. The inside is in a rich group III environment. Therefore, the content C concentration may be higher than that of the n-type nitride semiconductor layer 4.

  In the above embodiment, the case where Mg is used as the n-type impurity contained in the p-type nitride semiconductor layer 6 has been described. However, Be, Zn, and C can be used in addition to Mg.

(Later process)
After the formation of the p-type nitride semiconductor layer 6, the supply of TMA is stopped and the flow rate of Cp ₂ Mg is changed to 0.2 μmol / min and the source gas is supplied for 20 seconds. Thereby, a high concentration p-type GaN layer made of p-type GaN having a thickness of 5 nm is formed. Thereafter, annealing is performed.

  In the subsequent process, when a lateral structure is formed, a part of the upper surface of the n-type nitride semiconductor layer 4 is exposed by ICP etching, and an n electrode is formed on the exposed upper surface of the n-type nitride semiconductor layer 4 with a high concentration. A p-electrode is formed on the upper surface of the p-type GaN layer. In the case of forming a vertical structure, a metal electrode, a solder diffusion layer, and a solder layer to be a p-electrode are formed on the upper surface of the high-concentration p-type GaN layer. Then, after a conductor or semiconductor substrate (for example, a CuW substrate) is bonded through the solder layer, the support substrate 2 is peeled off by a method such as laser irradiation. Thereafter, an n-electrode is formed on the upper surface of the n-type nitride semiconductor layer 4.

[Example]
Hereinafter, description will be made with reference to examples.

  In the above-described process, only the V / III ratio of the source gas at the time of forming the n-type nitride semiconductor layer 4 is changed, and the other conditions are the same, so that Example 1, Example 2, Comparative Example 1, 4 elements of Comparative Example 2 were formed. Each element is an ultraviolet light emitting element having a main emission wavelength of 370 nm band.

-Example 1: It created by setting the V / III ratio to about 1000 and the furnace pressure to 10 kPa. The content C concentration of the n-type nitride semiconductor layer 4 is 1 × 10 ¹⁸ / cm ³ .
Example 2: Created with a V / III ratio of 1000. The content C concentration of n-type nitride semiconductor layer 4 is 5 × 10 ¹⁷ / cm ³ .
Comparative Example 1: Created with a V / III ratio of 2000. The content C concentration of n-type nitride semiconductor layer 4 is 1 × 10 ¹⁷ / cm ³ .
Comparative Example 2: Created with a V / III ratio of 4000. The concentration of C contained in n-type nitride semiconductor layer 4 is 5 × 10 ¹⁶ / cm ³ .

Further, instead of the support substrate 2, a support substrate 2a made of a PSS (Patterned-Sapphire-Substrate) sapphire substrate having irregularities of about 0.1 μm to 10 μm on the surface was used, and an element prepared with a V / III ratio of 1000 was implemented. Example 3 was used. At this time, the concentration of C contained in the n-type nitride semiconductor layer 4 is 5 × 10 ¹⁷ / cm ³ as in Example 2. As a difference in manufacturing from the element of Example 2, the growth film thickness of the undoped layer 3 (low-temperature buffer layer 3a, base layer 3b) is different. That is, in Example 3, after forming the low temperature buffer layer 3a having a thickness of 35 nm by supplying the source gas into the processing furnace for 119 seconds, the base layer 3b having a thickness of 6 μm is formed by supplying the source gas for 106 minutes. Formed. FIG. 1B is a schematic cross-sectional view of the nitride semiconductor light emitting device of Example 3.

In any element, the V / III ratio of the source gas at the time of forming the p-type nitride semiconductor layer 6 is 6000, and the content C concentration of the p-type nitride semiconductor layer 6 is 1 × 10 ¹⁷ / cm ³ . there were.

  FIG. 2 is a graph showing the spectral distribution of light obtained when the same voltage is applied to the five elements of Example 1, Example 2, Example 3, Comparative Example 1, and Comparative Example 2. The horizontal axis is the emission wavelength, and the vertical axis is the light intensity. FIG. 3 is a photograph showing the light emission states of the four elements of Example 1, Example 2, Comparative Example 1, and Comparative Example 2. In addition, although the photograph of the element of Example 3 is not shown in FIG. 3, the light emission state showed the brightness equivalent to or higher than the element of Example 1.

  According to FIG. 2, in Example 2, the intensity ratio of the emission wavelength (deep emission) in the 550 nm-600 nm band including the yellow visible light wavelength band to the emission intensity in the 370 nm band (main emission wavelength) ( The deep intensity ratio) is about 0.3%, exceeding 0.1%. In this case, if ultraviolet light is emitted, dark purple light should be emitted under the influence of purple visible light corresponding to the bottom of the peak wavelength. Due to the deep luminescence, it is shining quite whitish. The emission color is whitish due to the mixture of purple and yellow light.

  In Example 1, the deep intensity ratio is about 0.3%, which is higher than that in Example 2. From the photograph of FIG. 3, the intensity of yellow light is higher than that of Example 2 and the light is shining brighter. Thereby, it turns out that the brightness of an irradiation location increases because a deep intensity ratio becomes high. Furthermore, in Example 3, the deep intensity ratio is about 0.8%, which is higher than that in Example 2. When Example 2 and Example 3 are compared, since the content C concentration of both n-type nitride semiconductor layers 4 is made the same value, deep strength is further increased by using the support substrate 2a made of a PSS sapphire substrate. It turns out that an effect is acquired.

  On the other hand, in Comparative Example 1, the deep intensity ratio is 0.1%. From the photograph in FIG. 3, it can be seen that, compared with Example 1 and Example 2, the whitish color is reduced from the emission color of the irradiated portion, and the color is darker. Furthermore, in Comparative Example 2 where the deep intensity ratio is lower than that of Comparative Example 1, the emission color of the irradiated portion is a darker color according to the photograph of FIG. In the photograph of FIG. 3, when the deep intensity ratio is 0.1% as in Comparative Example 1, the irradiated portion is projected a little whitish. It becomes difficult to determine whether or not.

As in Comparative Example 1, the V / III ratio of the source gas at the time of forming the p-type nitride semiconductor layer 6 with the content C concentration of the n-type nitride semiconductor layer 4 set to 1 × 10 ¹⁷ / cm ^3. , And the same measurement was performed by increasing the content C concentration of the p-type nitride semiconductor layer 6 to 1 × 10 ¹⁹ / cm ³ , but no significant difference from Comparative Example 1 was obtained. That is, even if the content C concentration of the p-type nitride semiconductor layer 6 is increased, the effect of increasing the deep emission intensity cannot be obtained, and the content C concentration of the n-type nitride semiconductor layer 4 affects the deep emission. I understand.

  That is, it can be seen that deep light emission originates from the impurity level produced by C contained in the n-type nitride semiconductor layer 4. From this, the deep emission intensity can be increased by increasing the concentration of C contained in the n-type nitride semiconductor layer 4 as much as possible.

As described above, by setting the C concentration contained in the n-type nitride semiconductor layer 4 to a range exceeding 1 × 10 ¹⁷ / cm ³ , the deep intensity ratio of the light emitted from the nitride semiconductor light-emitting element 1 is 0. Since it exceeds 1% and the brightness of the irradiated portion increases, it is possible to visually determine whether or not the light from the nitride semiconductor light emitting device 1 is irradiated to the irradiated portion.

[Another embodiment]
The nitride semiconductor light emitting device 1 shown in FIG. 1A has the support substrate 2 and the undoped layer 3, but may have a configuration in which these are peeled off (see FIG. 4). Also in this case, the same effect as the element of each Example mentioned above with reference to FIG.2 and FIG.3 was acquired.

1: Nitride semiconductor light emitting device
2, 2a: Support substrate
3: Undoped layer
3a: Low temperature buffer layer
3b: Underlayer
4: n-type nitride semiconductor layer
5: Light emitting layer
6: p-type nitride semiconductor layer

Claims (4)

A nitride semiconductor light emitting device having a light emitting layer between an n type nitride semiconductor layer and a p type nitride semiconductor layer,
The main emission wavelength is ultraviolet light of 375 nm or less,
The n-type nitride semiconductor _layer, Al _{n Ga} include _1-n N a (0 ≦ n ≦ 1), Ri range der the C concentration contained exceeds 1 × ¹⁰ 17 / cm ^3,
A nitride semiconductor light emitting device characterized in that the emission intensity of yellow visible light wavelength exceeds 0.1% with respect to the emission intensity of the main emission wavelength . 2. The nitride semiconductor light emitting device according to claim 1, wherein the n-type nitride semiconductor layer has a C concentration of 5 × 10 ¹⁷ / cm ³ or more. A method for manufacturing a nitride semiconductor light emitting device , comprising:
The nitride semiconductor light emitting device is
A nitride semiconductor light emitting device having a light emitting layer between an n type nitride semiconductor layer and a p type nitride semiconductor layer,
The main emission wavelength is ultraviolet light of 375 nm or less,
The n-type nitride semiconductor layer includes Al _n Ga _1-n N (0 ≦ n ≦ 1), and the contained C concentration is in a range exceeding 1 × 10 ¹⁷ / cm ³ ;
Forming the n-type nitride semiconductor layer (a),
Forming the light emitting layer (b),
And (c) forming the p-type nitride semiconductor layer,
The step (a) is a step of supplying a source gas having a V / III ratio of less than 2000, which is a ratio of a flow rate of a compound containing a group V element to a flow rate of a compound containing a group III element, into a processing furnace to grow crystals. A method for producing a nitride semiconductor light emitting device, wherein: 4. The nitride semiconductor light emitting device according to claim 3, wherein the light emission intensity of yellow visible light wavelength exceeds 0.1% with respect to the light emission intensity of the main light emission wavelength. 5. Manufacturing method.