JP5633154B2 - Semiconductor light emitting device manufacturing method, semiconductor light emitting device, lamp, electronic device, and mechanical device - Google Patents

Description

  The present invention relates to a method for manufacturing a semiconductor light-emitting element and a semiconductor light-emitting element, a lamp, an electronic device, and a mechanical device. Particularly, the present invention is preferably used when a large current is applied, and has a high light emission output when the large current is applied. The present invention relates to a method for manufacturing a semiconductor light-emitting element that can be obtained, and a lamp, an electronic device, and a mechanical device including the semiconductor light-emitting element manufactured by using this manufacturing method.

  2. Description of the Related Art Conventionally, as a semiconductor light emitting element used for a light emitting diode or the like, there is one in which an n type semiconductor layer, a light emitting layer, and a p type semiconductor layer are sequentially stacked on a substrate. As a method for manufacturing such a semiconductor light emitting device, an n-type semiconductor layer, a light emitting layer, and a p layer are formed on a substrate made of a sapphire single crystal by a metal organic chemical vapor deposition (MOCVD) method. There is a method of successively and successively stacking a type semiconductor layer.

  However, when an n-type semiconductor layer, a light emitting layer, and a p-type semiconductor layer are sequentially and sequentially stacked on a substrate, these layers are formed in the same growth chamber. Therefore, the dopant used when forming the n-type semiconductor layer hinders the formation of the p-type semiconductor layer, and a p-type semiconductor layer having a sufficiently low resistivity may not be obtained.

  As a technique for solving such a problem, for example, Patent Document 1 discloses a compound semiconductor device in which at least a first conductivity type semiconductor layer and a second conductivity type semiconductor layer are sequentially formed on a predetermined substrate. In manufacturing a compound semiconductor device, a semiconductor layer of each conductivity type is formed in a plurality of different independent growth chambers corresponding to the conductivity type.

  Recently, in order to improve the light emission output of the semiconductor light emitting device, a large current is often applied to the semiconductor light emitting device, and the resistance of the n-type semiconductor layer and the p-type semiconductor layer is required to be reduced. ing.

Japanese Unexamined Patent Publication No. 7-45538

  The present invention has been made in view of the above problems, and provides a method for manufacturing a semiconductor light emitting device having a high light emission output when a large current is applied, by suppressing the resistance of the n-type semiconductor layer and the p-type semiconductor layer to be low. The task is to do.

In order to achieve the above object, the present invention provides the following means.
[1] In a first organometallic chemical vapor deposition apparatus, a first step of laminating a first n-type semiconductor layer on a substrate, and a second organometallic chemical vapor deposition different from the first organometallic chemical vapor deposition apparatus. In the growth apparatus, a regrowth layer of the first n-type semiconductor layer, a second n-type semiconductor layer, a light emitting layer, a p-type semiconductor layer including a p-cladding layer and a p-contact layer are formed on the first n-type semiconductor layer. ; and a second step of sequentially laminating, the in the step of laminating the regrown layer, prior SL layer for supplying a small amount of Si than when the first n-type semiconductor layer formed as a dopant, or stacked layers is not supplied as Engineering and (2), a semiconductor light emission and performs a process (3) for supplying the first n-type semiconductor layer formed at the same amount or a large amount of the Si than as a dopant in this order Device manufacturing method.
[2] The method for manufacturing a semiconductor light-emitting element according to [1], wherein the regrowth layer is formed by supplying a dopant gas containing Si together with a source gas of the regrowth layer.
[3] The method for manufacturing a semiconductor light-emitting element according to [1] or [2], wherein the step (2) is started simultaneously with the start of the formation of the regrowth layer or in the middle of the formation.
[4] The supply amount of the dopant gas in the step (2) is 0 to 1/15 times that in forming the first n-type semiconductor layer, and the supply amount of the dopant gas in the step (3) is the first n. The method of manufacturing a semiconductor light-emitting element according to any one of [1] to [3], which is 1 to 4 times as large as that at the time of forming the semiconductor layer.
[5] The method for manufacturing a semiconductor light-emitting element according to [1] to [4], wherein the thickness of the regrown layer is 0.1 μm to 3.5 μm.
[6] before Symbol regrown layer the second layer having a thickness of 0.05μm~0.5μm formed in the step (2), the regrown layer a third layer of thickness 0.05μm~1μm in the step (3) The method for manufacturing a semiconductor light-emitting element according to any one of [1] to [5], wherein:
[7] The step of laminating the regrowth layer includes a step (1) in which, before the step (2), the regrowth layer is grown under the same growth conditions as in the formation of the first n-type semiconductor layer. The semiconductor light emitting device according to any one of [1] to [6].
[8] A regrowth layer first layer having a thickness of 2 μm or less is formed in the step (1), and a regrowth layer second layer having a thickness of 0.05 μm to 0.5 μm is formed in the step (2). In the step (3), a third layer of a regrowth layer having a film thickness of 0.05 μm to 1 μm is formed.
[ 9 ] Of the regrowth layer, the second layer of the regrowth layer contains Si at a concentration of less than 1 × 10 ¹⁷ / cm ^{3, and} the third layer of the regrowth layer contains 5 × 10 ^{18 of} Si. The method for producing a semiconductor light-emitting element according to any one of [6] to [8] , wherein the semiconductor light-emitting element is contained at a concentration of / cm ³ or more.
[ 10 ] The p contact layer is formed by laminating a p contact lower layer and a p contact upper layer, and Mg is contained in the p contact lower layer in a concentration of about 1 × 10 ¹⁹ to 1 × 10 ²⁰ / cm ^3. In the semiconductor light-emitting device according to any one of [1] to [ 9 ], the Mg layer is contained in the p contact upper layer at a concentration of about 1 × 10 ²⁰ / cm ^{3 to} 3 × 10 ²⁰ / cm ³ . Production method.
[ 11 ] A first n-type semiconductor layer stacked on a substrate in a first metal organic chemical vapor deposition apparatus and a second metal organic chemical vapor deposition apparatus different from the first metal organic chemical vapor deposition apparatus. been, a semiconductor light emitting device regrown layer and the second n-type semiconductor layer and the p-type semiconductor layer comprising a light-emitting layer and a p-cladding layer and a p-contact layer are laminated in the first n-type semiconductor layer, The regrown layer is a first regrown layer having the same Si content as the first n-type semiconductor layer, a second regrown layer having a lower Si content than the first n-type semiconductor layer, and the first n A semiconductor light emitting device characterized in that a third layer of a regrown layer having a Si content higher than that of a type semiconductor layer is laminated in this order.
[1 2] of the regrown layer, before Symbol regrown layer second layer 0.05Myuemu～0.5Myuemu, the regrown layer third layer are formed with a thickness of 0.05μm~1μm [ 11 ] The semiconductor light-emitting device according to [ 11 ].
[13]
The regrowth layer has a structure in which a regrowth layer first layer having the same Si content as that of the first n-type semiconductor layer is laminated on the opposite side of the regrowth layer third layer of the second regrowth layer. [10] The semiconductor light-emitting device described in [10].
[14]
Among the regrowth layers, the first regrowth layer is 2 μm or less, the second regrowth layer is 0.05 μm to 0.5 μm, and the third regrowth layer is 0.05 μm to 1 μm. [13] The semiconductor light-emitting device according to [13].
[1 5 ] Among the regrowth layers, the second layer of regrowth layers contains Si at a concentration of less than 1 × 10 ¹⁷ / cm ^{3, and} the third layer of regrowth layers contains 5 × 10 Si. ¹⁸ / cm ^3, characterized in that it is contained in concentrations above [11] to the semiconductor light-emitting device according to [1 4].
[1 6] The semiconductor light emitting device according to the thickness of the regrowth layer is characterized in that it is a 0.1μm~3μm [11] to [1 5].
[1 7 ] The p contact layer is formed by laminating a p contact lower layer and a p contact upper layer, and Mg is contained in the p contact lower layer at a concentration of about 1 × 10 ¹⁹ to 1 × 10 ²⁰ / cm ^3. The semiconductor light emitting device according to any one of [ 11 ] to [ 16 ], wherein the Mg is contained in the upper layer of the p contact at a concentration of about 1 × 10 ²⁰ / cm ^{3 to} 3 × 10 ²⁰ / cm ^3. .
[1 8 ] A lamp comprising a semiconductor light emitting device manufactured using the semiconductor light emitting device according to any one of [ 11 ] to [1 7 ].
[1 9 ] An electronic device in which the lamp according to [1 8 ] is incorporated.
[ 20 ] A mechanical apparatus in which the electronic device according to [1 9 ] is incorporated.

  According to the method for manufacturing a semiconductor light emitting device of the present invention, in the step of laminating the regrown layer of the first n-type semiconductor layer in the second growth chamber (second organometallic chemical vapor deposition apparatus), the first n Supplying the same amount of Si as the dopant when forming the semiconductor layer (1), supplying a smaller amount of Si as a dopant than when forming the first n-type semiconductor layer (2), and the first n-type By performing in this order the step (3) of supplying a larger amount of Si as a dopant than when forming the semiconductor layer, the Si content in the regrowth layer can be changed stepwise.

  As a result, the resistance of the regrowth layer can be lowered and the flatness of the regrowth layer surface can be improved. Therefore, a light-emitting layer (MQW layer) or a p-type semiconductor layer with good crystallinity can be grown in subsequent steps. Moreover, since a current can be diffused by forming a layer having a high Si concentration in the regrowth layer, it is possible to effectively prevent the concentration of light emitting points even if a high current is passed through the LED. Become. Furthermore, since the n-contact layer occupying most of the n-type semiconductor layer and the p-type semiconductor layer are formed in different growth chambers, mixing of n-type impurities into the p-type semiconductor layer can be suppressed. As a result, a semiconductor light emitting device having a high light emission output when a large current is applied can be obtained.

FIG. 1 is a schematic cross-sectional view showing an example of a semiconductor light emitting device manufactured using the method for manufacturing a semiconductor light emitting device of the present invention. FIG. 2 is a schematic cross-sectional view for explaining a process for manufacturing the semiconductor light emitting element shown in FIG. FIG. 3 is a schematic cross-sectional view showing an example of a lamp including the semiconductor light emitting element shown in FIG. FIG. 4 is a graph showing the relationship between the applied current and the power efficiency of the semiconductor light emitting devices of Examples 1 to 5 and Comparative Example 1. FIG. 5 is a graph showing the relationship between the applied current and the light emission output of the semiconductor light emitting devices of Examples 1 to 5 and Comparative Example 1.

  Hereinafter, the semiconductor light emitting device 1 of the present invention will be described in detail with reference to FIG. Note that the drawings referred to in the following description may show the characteristic portions in an enlarged manner for the sake of convenience, and the dimensional ratios of the respective components are not always the same as the actual ones. In addition, the materials, dimensions, and the like exemplified in the following description are examples, and the present invention is not limited to them, and can be appropriately changed and implemented without changing the gist thereof.

FIG. 1 is a schematic cross-sectional view showing an example of a semiconductor light emitting device 1 of the present invention.
A semiconductor light emitting device 1 according to this embodiment shown in FIG. 1 includes a substrate 11, a laminated semiconductor layer 20 laminated on the substrate 11, a translucent electrode 15 laminated on the upper surface of the laminated semiconductor layer 20, The p-type bonding pad electrode 16 laminated on the conductive electrode 15 and the n-type electrode 17 laminated on the exposed surface 20a of the laminated semiconductor layer 20 are schematically configured.

The stacked semiconductor layer 20 is configured by stacking an n-type semiconductor layer 12, a light emitting layer 13, and a p-type semiconductor layer 14 in this order from the substrate 11 side. As shown in FIG. 1, the n-type semiconductor layer 12, the light emitting layer 13, and the p-type semiconductor layer 14 are partially removed by means such as etching, and one part of the n-type semiconductor layer 12 is removed from the removed portions. The part is exposed. An n-type electrode 17 is stacked on the exposed surface 20 a of the n-type semiconductor layer 12.
A translucent electrode 15 and a p-type bonding pad electrode 16 are stacked on the upper surface of the p-type semiconductor layer 14. The translucent electrode 15 and the p-type bonding pad electrode 16 constitute a p-type electrode 18.

As a semiconductor constituting the n-type semiconductor layer 12, the light emitting layer 13, and the p-type semiconductor layer 14, a group III nitride semiconductor is preferably used, and a gallium nitride compound semiconductor is more preferably used. As the gallium nitride-based compound semiconductor constituting the n-type semiconductor layer 12, the light emitting layer 13, and the p-type semiconductor layer 14 in the present invention, a general formula Al _x In _y Ga _1-xy N (0 <x <1,0 Semiconductors having various compositions represented by ≦ y <1, 0 <x + y <1) can be used without any limitation.

The semiconductor light emitting device 1 of the present embodiment can emit light from the light emitting layer 13 constituting the laminated semiconductor layer 20 by passing a current between the p-type electrode 18 and the n-type electrode 17. This is a face-up mount type light emitting element that extracts light from the light emitting layer 13 from the side where the p type bonding pad electrode 16 is formed. The semiconductor light emitting device of the present invention may be a flip chip type light emitting device.
Hereinafter, each configuration will be described in detail.

<Substrate 11>
Examples of the substrate 11 include sapphire, SiC, silicon, zinc oxide, magnesium oxide, manganese oxide, zirconium oxide, manganese zinc iron, magnesium aluminum oxide, zirconium boride, gallium oxide, indium oxide, lithium gallium oxide, and lithium oxide. A substrate formed of aluminum, neodymium gallium oxide, lanthanum strontium aluminum tantalum, strontium titanium oxide, titanium oxide, hafnium, tungsten, molybdenum, or the like can be used. Among the above substrates, it is particularly preferable to use a sapphire substrate having a c-plane as a main surface.

(Buffer layer 21)
The buffer layer 21 may not be provided, but the difference in lattice constant between the substrate 11 and the base layer 22 is alleviated to form a C-axis oriented single crystal layer on the (0001) C plane of the substrate 11. It is preferable that it is provided in order to facilitate the process. When the single crystal underlayer 22 is laminated on the buffer layer 21, the underlayer 22 with better crystallinity can be laminated.

The buffer layer 21 is particularly preferably made of single crystal Al _x Ga _1-x N (0 <x ≦ 1), but is made of polycrystalline Al _x Ga _1-x N (0 <x ≦ 1). It doesn't matter.
The buffer layer 21 can be, for example, made of polycrystalline Al _x Ga _1-x N (0 <x ≦ 1) and having a thickness of 0.01 to 0.5 μm. If the thickness of the buffer layer 21 is less than 0.01 μm, the buffer layer 21 may not sufficiently obtain the effect of reducing the difference in lattice constant between the substrate 11 and the base layer 22. Further, when the thickness of the buffer layer 21 exceeds 0.5 μm, the film forming process time of the buffer layer 21 becomes long and the productivity is lowered although the function as the buffer layer 21 is not changed. There's a problem.

  The buffer layer 21 may have a polycrystalline structure or a single crystal structure. When the buffer layer 21 having such a polycrystalline structure or a single crystal structure is formed on the substrate 11 by the MOCVD method or the sputtering method, the buffer function of the buffer layer 21 works effectively. The group III nitride semiconductor thus formed becomes a crystal film having good orientation and crystallinity.

(Underlayer 22)
As the material of the underlayer 22, it is particularly preferable to use Al _x Ga _1-x N (0 <x <1) because the underlayer 22 with good crystallinity can be formed. However, Al _x Ga _y In _z N (0 < x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ z ≦ 1, x + y + z = 1) may be used.
The film thickness of the underlayer 22 is preferably 0.1 μm or more, more preferably 0.5 μm or more, and most preferably 1 μm or more. An Al _x Ga _1-x N layer with good crystallinity is more easily obtained when the thickness is increased. Further, the film thickness of the underlayer 22 is preferably 10 μm or less.
In order to improve the crystallinity of the underlayer 22, it is desirable that the underlayer 22 is not doped with impurities. However, when p-type or n-type conductivity is required, acceptor impurities or donor impurities can be added to the base layer 22.

<Laminated semiconductor layer 20>
(N-type semiconductor layer 12)
The n-type semiconductor layer 12 further includes an n-contact layer 12a (first n-type semiconductor layer 12c and regrowth layer 12d) and an n-cladding layer 12b (second n-type semiconductor layer).

(N contact layer 12a)
The n contact layer 12a is a layer for providing the n-type electrode 17, and includes a first n-type semiconductor layer 12c formed in a first step described later, and a regrown layer 12d formed in a second step described later. Consists of. The first n-type semiconductor layer 12c and the regrowth layer 12d are preferably made of the same material, and the thickness of the first n-type semiconductor layer 12c is larger than the thickness of the regrowth layer 12d. Yes.
In the present embodiment, as shown in FIG. 1, an exposed surface 20a for providing the n-type electrode 17 is formed on the first n-type semiconductor layer 12c. The exposed surface 20a for providing the n-type electrode 17 may be formed in the regrowth layer 12d.

The n-contact layer 12a is preferably composed of an Al _x Ga _1-x N layer (0 <x <1, preferably 0 <x ≦ 0.5, more preferably 0 <x ≦ 0.1). An n-type impurity (dopant) is doped. When n-type impurity is contained in n contact layer 12a at a concentration of 1 × 10 ¹⁷ to 1 × 10 ²⁰ / cm ³ , preferably 1 × 10 ¹⁸ to 1 × 10 ¹⁹ / cm ³ , From the viewpoint of maintaining good ohmic contact. The n-type impurity used for the n-contact layer 12a is not particularly limited, and examples thereof include Si, Ge, Sn, etc., Si and Ge are preferable, and Si is most preferable. In the present embodiment, Si is contained.

The film thickness of the first n-type semiconductor layer 12c constituting the n-contact layer 12a is preferably 0.5 to 5 μm, and more preferably 2 to 4 μm. When the film thickness of the first n-type semiconductor layer 12c is within the above range, the crystallinity of the semiconductor is favorably maintained. The first n-type semiconductor layer 12c contains about 5 × 10 ¹⁸ / cm ³ of Si as an n-type impurity (dopant).

  The regrowth layer 12d of this embodiment is formed with a film thickness of 0.1 μm to 3 μm, and contains Si as an n-type impurity (dopant). Si is gradually contained in the regrowth layer 12d, and the regrowth layer first layer has the same Si content as the first n-type semiconductor layer 12c. The regrowth layer contains less Si than the first n-type semiconductor layer 12c. A second growth layer and a third regrowth layer having a Si content higher than that of the first n-type semiconductor layer 12c are stacked in this order. In addition, the regrowth layer 12d only needs to be provided with at least the second regrowth layer and the third regrowth layer, and the first regrowth layer may not be provided.

The first regrowth layer is preferably formed with a thickness of 0 μm to 2 μm. Although the first regrowth layer may not be formed (thickness 0 μm), the entire regrowth layer 12d is formed according to the thickness of the second regrowth layer and the third regrowth layer described later. What is necessary is just to form so that thickness may become an optimal value suitably.
Further, the concentration of Si contained in the first regrowth layer is adjusted so that the driving voltage Vf when a current is passed through the semiconductor light emitting device 1 becomes a predetermined value. It is preferably about 5 × 10 ¹⁸ / cm ³ which is the same as the layer 12c.

  The second regrowth layer is preferably formed with a film thickness of 0.05 μm to 0.5 μm. When the thickness of the second layer of the regrown layer is less than 0.05 μm, the surface of the second layer of the regrown layer is not formed with sufficient flatness, and the surface of the regrown layer 12d is not sufficiently flattened. On the other hand, when the film thickness exceeds 0.5 μm, the driving voltage Vf when a current is passed through the semiconductor light emitting element 1 becomes high, and the light emission efficiency of the semiconductor light emitting element 1 becomes low.

Moreover, it is preferable that the density | concentration of Si contained in the regrowth layer 2nd layer is less than 1 * 10 < ¹⁷ > / cm < ³ >. This is because when the Si concentration is 1 × 10 ¹⁷ / cm ³ or more, the crystallinity improvement effect is reduced.
Here, the Si content of the second regrowth layer is smaller than that of the first n-type semiconductor layer 12c. By setting the Si content within the above range, the crystallinity of the second layer of the regrown layer becomes high, and the flatness of the surface becomes sufficiently high.

The third regrowth layer is preferably formed with a film thickness of 0.05 μm to 1 μm. If the thickness of the third layer of the regrown layer is less than 0.05 μm, the resistance of the regrown layer 12d cannot be sufficiently lowered.
Further, when the thickness of the third layer of the regrown layer exceeds 1 μm, the flatness of the surface of the third layer of the regrown layer is deteriorated, and the reverse current (IR) of the semiconductor light emitting element 1 is increased, which is not preferable. In addition, the p-type semiconductor layer 14 is likely to be defective due to the dopant and deposit used when forming the third regrowth layer. Furthermore, there is a problem that the film formation processing time of the third layer of the regrown layer becomes long and productivity is lowered.

Moreover, it is preferable that the density | concentration of Si contained in the regrowth layer 3rd layer is a density | concentration of 5 * 10 < ¹⁸ > / cm < ³ > or more. If the Si concentration is less than 5 × 10 ¹⁸ / cm ³ , the resistance of the regrowth layer 12d cannot be sufficiently lowered.
Here, the Si content of the third layer of the regrown layer is equal to or higher than that of the first n-type semiconductor layer 12c. In addition, by setting the Si content within the above range, the resistance of the third layer of the regrown layer can be lowered and the current spreading effect can be enhanced.

  The regrown layer second layer surface is formed with high flatness, and the regrown layer third layer is laminated thereon. Therefore, the third layer of the regrown layer has good crystallinity even when the Si concentration is high, and the surface flatness is also good. As a result, the surface of the regrowth layer 12d on the n-cladding layer 12b side (the surface of the regrowth layer third layer) is formed flat.

If Si of 1 × 10 ¹⁹ / cm ³ or more is contained in the entire regrowth layer 12d, the resistance of the regrowth layer is lowered, but pits are easily formed. Therefore, the reverse current IR when current is passed Rise and electrostatic discharge (ESD) breakdown voltage may be insufficient. However, in this embodiment, by forming the third layer of the regrown layer on the second layer of the regrown layer, the formation of pits can be suppressed and the reverse current IR can be lowered.

Further, when the Si content of the entire regrowth layer 12d is less than 1 × 10 ¹⁷ / cm ³ , the resistance becomes too large, the operating voltage of the semiconductor light emitting device 1 becomes high, the current is concentrated, and the light emission output is increased. There was a problem of lowering. However, in the present embodiment, by reducing the thickness of the second layer of the regrown layer, it is possible to prevent the operating voltage of the semiconductor light emitting device 1 from increasing and the light emission output from decreasing, and the third layer of the regrown layer. The current can be diffused in.
Therefore, even for a high-current LED, it is possible to effectively prevent concentration of light emission points while preventing a decrease in light emission output.

The n clad layer 12 b is provided between the n contact layer 12 a and the light emitting layer 13.
The n-cladding layer 12b is a layer for injecting carriers into the light emitting layer 13 and confining carriers, and also serves as a buffer layer for the light emitting layer 13 that alleviates the mismatch of the crystal lattice between the regrown layer 12d and the light emitting layer 13. It functions. The n-clad layer 12b can be formed of AlGaN, GaN, GaInN, or the like. In the specification, the composition ratio of each element may be omitted and described as AlGaN, GaN, or GaInN. Needless to say, when the n-cladding layer 12b is formed of GaInN, it is desirable to make it larger than the band gap of GaInN of the light emitting layer 13.

When the n clad layer 12b is a single layer, the film thickness of the n clad layer 12b is preferably 5 to 500 nm, more preferably 5 to 100 nm. Moreover, it is preferable that the n-type dope density | concentration of the n clad layer 12b is 1 * 10 < ¹⁷ > -1 * 10 < ²⁰ > / cm < ³ >, More preferably, it is 1 * 10 < ¹⁸ > -1 * 10 < ¹⁹ > / cm < ³ >. In the present embodiment, for example, Si is contained in the same amount as the first n-type semiconductor layer 12c, for example, about 5 × 10 ¹⁸ / cm ³ . When the doping concentration is within this range, it is preferable in terms of maintaining good crystallinity and reducing the operating voltage of the light emitting element.

  In this embodiment, the n-clad layer 12b may be a single layer, but consists of 10 pairs (20 layers) to 40 pairs (80 layers) by repeatedly growing two thin film layers having different compositions. A superlattice structure is preferred. When the n-cladding layer 12b has a superlattice structure, if the number of thin film layers is 20 or more, the crystal lattice mismatch between the regrown layer 12d and the light-emitting layer 13 is more effectively mitigated. Therefore, the effect of improving the output of the semiconductor light emitting device 1 becomes more remarkable. However, if the number of thin film layers exceeds 80, the superlattice structure may be easily disturbed, and the light emitting layer 13 may be adversely affected. Furthermore, there is a problem that the film forming process time of the n-clad layer 12b becomes long and productivity is lowered.

  The superlattice structure constituting the n-clad layer 12b includes an n-side first layer made of a group III nitride semiconductor and an n-side second layer made of a group III nitride semiconductor having a composition different from that of the n-side first layer. Are preferably laminated, and more preferably include a structure in which n-side first layers and n-side second layers are alternately and repeatedly laminated.

  The n-side first layer and the n-side second layer constituting the superlattice structure of the n-clad layer 12b are composed of GaInN / GaN alternating structure, AlGaN / GaN alternating structure, GaInN / AlGaN alternating structure, GaInN / An alternate structure of GaInN (in the present invention, the description of “different composition” indicates that each elemental composition ratio is different), an alternate structure of AlGaN / AlGaN having a different composition, and an alternate structure of GaInN / GaN. Alternatively, an alternate structure of GaInN / GaInN having different compositions is preferable.

  The film thicknesses of the n-side first layer and the n-side second layer are each preferably 100 angstroms or less, more preferably 60 angstroms or less, further preferably 40 angstroms or less, and each 10 angstroms to Most preferably, it is in the range of 40 Angstroms. If the film thickness of the n-side first layer and / or the n-side second layer forming the superlattice layer is more than 100 angstroms, crystal defects are likely to occur, which is not preferable.

  Each of the n-side first layer and the n-side second layer may have a doped structure, or a combination of a doped structure / undoped structure. As the impurity to be doped, conventionally known impurities can be applied to the material composition without any limitation. For example, in the case where a superlattice structure having an alternate structure of GaInN / GaN or an alternate structure of GaInN / GaInN having a different composition is used as the n-clad layer 12b, Si is suitable as an impurity. Further, the n-side first layer and the n-side second layer constituting the superlattice structure have the same composition represented by GaInN, AlGaN, and GaN, and are a combination of a doped structure and an undoped structure. Also good.

<Light emitting layer 13>
The light emitting layer 13 has a multiple quantum well structure in which a plurality of barrier layers 13a and well layers 13b are alternately stacked. The number of stacked layers in the multiple quantum well structure is preferably 3 to 10 layers, more preferably 4 to 7 layers.

(Well layer 13b)
The thickness of the well layer 13b is preferably in the range of 15 angstroms or more and 50 angstroms or less. When the film thickness of the well layer 13b is within the above range, a higher light emission output can be obtained.
The well layer 13b is preferably a gallium nitride compound semiconductor containing In. A gallium nitride compound semiconductor containing In is preferable because it emits strong light in the blue wavelength region. The well layer 13b can be doped with impurities. As the dopant, it is preferable to use Si or Ge which enhances the emission intensity. The dope amount is preferably about 1 × 10 ¹⁷ cm ⁻³ to 1 × 10 ¹⁸ cm ⁻³ . When the doping amount is in the above range, the emission intensity is stronger.

(Barrier layer 13a)
The thickness of the barrier layer 13a is preferably in the range of 20 angstroms or more and less than 100 angstroms. If the thickness of the barrier layer 13a is too thin, flattening of the upper surface of the barrier layer 13a is hindered, resulting in a decrease in light emission efficiency and a decrease in aging characteristics. Moreover, when the film thickness of the barrier layer 13a is too thick, a drive voltage rises and light emission falls. Therefore, the thickness of the barrier layer 13a is more preferably 70 angstroms or less.
In addition to GaN and AlGaN, the barrier layer 13a can be formed of InGaN having a smaller In ratio than InGaN constituting the well layer. Among these, GaN is preferable.

<P-type semiconductor layer 14>
The p-type semiconductor layer 14 is generally composed of a p-cladding layer 14a and a p-contact layer 14b. Further, the p contact layer 14b can also serve as the p clad layer 14a.

(P-clad layer 14a)
The p-cladding layer 14a is a layer for confining carriers in the light emitting layer 13 and injecting carriers. The p-cladding layer 14a is not particularly limited as long as it has a composition larger than the band gap energy of the light-emitting layer 13 and can confine carriers in the light-emitting layer 13, but Al _x Ga _1-x N (0 < x ≦ 0.4) is preferable. When the p-cladding layer 14a is made of such AlGaN, it is preferable in terms of confining carriers in the light-emitting layer 13.

The thickness of the p-cladding layer 14a is not particularly limited, but is preferably 1 to 400 nm, and more preferably 5 to 100 nm. The p-type doping concentration of the p-cladding layer 14a is preferably 1 × 10 ¹⁸ to 1 × 10 ²¹ / cm ³ , more preferably 1 × 10 ¹⁹ to 1 × 10 ²⁰ / cm ³ . When the p-type dope concentration is in the above range, a good p-type crystal can be obtained without reducing the crystallinity. The p-cladding layer 14a may have a superlattice structure in which thin films are stacked a plurality of times.

  When the p-cladding layer 14a includes a superlattice structure, a p-side first layer made of a group III nitride semiconductor and a p-side second made of a group III nitride semiconductor having a composition different from that of the p-side first layer. The layers may be stacked. When the p-cladding layer 14a includes a superlattice structure, the p-cladding layer 14a may include a structure in which p-side first layers and p-side second layers are alternately and repeatedly stacked.

  The p-side first layer and the p-side second layer constituting the superlattice structure of the p-cladding layer 14a may have different compositions, for example, any composition of AlGaN, GaInN, or GaN. GaInN / GaN Alternatively, an alternate structure of AlGaN / GaN, or an alternate structure of GaInN / AlGaN may be used. In the present invention, the p-side first layer and the p-side second layer preferably have an AlGaN / AlGaN or AlGaN / GaN alternating structure.

  The film thicknesses of the p-side first layer and the p-side second layer are each preferably 100 angstroms or less, more preferably 60 angstroms or less, further preferably 40 angstroms or less, and each 10 angstroms to Most preferably, it is in the range of 40 Angstroms. If the thickness of the p-side first layer and the p-side second layer forming the superlattice layer is more than 100 angstroms, crystal defects are likely to occur, which is not preferable.

  Each of the p-side first layer and the p-side second layer may have a doped structure, or a combination of a doped structure and an undoped structure. As the impurity to be doped, conventionally known impurities can be applied to the material composition without any limitation. For example, when a superlattice structure having an AlGaN / GaN alternating structure or an AlGaN / AlGaN alternating structure having a different composition is used as the p-cladding layer, Mg is suitable as the impurity. Further, the p-side first layer and the p-side second constituting the superlattice structure have the same composition represented by GaInN, AlGaN, and GaN, and may be a combination of a doped structure / undoped structure. Good.

(P contact layer 14b)
The p contact layer 14b is a layer for providing a positive electrode. The p contact layer 14b is preferably made of Al _x Ga _1-x N (0 <x ≦ 0.4) in terms of maintaining good crystallinity and good ohmic contact with the p ohmic electrode. . Further, when the p-type impurity (dopant) contains 1 × 10 ¹⁸ to 1 × 10 ²¹ / cm ³ at a concentration of 5 × 10 ^{19 to} 5 × 10 ²⁰ / cm ³ , good ohmic contact It is preferable from the standpoints of maintaining the thickness, preventing the occurrence of cracks, and maintaining good crystallinity. Although it does not specifically limit as a p-type impurity, For example, it is preferable to use Mg.

The p contact layer 14b is formed by laminating a p contact lower layer and a p contact upper layer, and Mg is contained in the p contact lower layer at a concentration of about 1 × 10 ¹⁹ to 1 × 10 ²⁰ / cm ^3. It is particularly preferable that the two layers contain Mg at a concentration of about 1 × 10 ²⁰ / cm ^{3 to} 3 × 10 ²⁰ / cm ³ . Thereby, Mg is contained at a high concentration in the portion in contact with the translucent electrode 15 (p contact upper layer), and the surface thereof is formed flat. Therefore, the light emission output of the semiconductor light emitting element 1 can be further improved.

The thickness of the p-contact layer 14b is not particularly limited, but is preferably 10 to 500 nm, and more preferably 50 to 200 nm. When the film thickness of the p contact layer 14b is within this range, it is preferable in terms of light emission output.
Further, when the p-contact layer 14b has a two-layer structure including a p-contact upper layer and a p-contact lower layer, the p-contact layer 14b is preferably 50 to 500 nm, more preferably 50 to 500 nm. 320 nm is preferable. When the film thickness of the p contact layer 14b is within this range, it is preferable in terms of light emission output. The p contact upper layer occupying the p contact layer 14b preferably has a thickness of about 6% to 40%.

<N-type electrode 17>
The n-type electrode 17 also serves as a bonding pad, and is formed in contact with the n-type semiconductor layer 12 of the laminated semiconductor layer 20. Therefore, when forming the n-type electrode 17, at least a part of the p-semiconductor layer 14 and the light-emitting layer 13 is removed to expose the n-type semiconductor layer 12, and on the exposed surface 20 a of the n-type semiconductor layer 12. An n-type electrode 17 also serving as a bonding pad is formed. As the n-type electrode 17, various compositions and structures are known, and these known compositions and structures can be used without any limitation, and can be provided by conventional means well known in this technical field.

(Translucent electrode 15)
The translucent electrode 15 is laminated on the p-type semiconductor layer 14 and preferably has a small contact resistance with the p-type semiconductor layer 14. Further, the translucent electrode 15 is preferably excellent in light transmissivity in order to efficiently extract light from the light emitting layer 13 to the outside of the semiconductor light emitting element 1. In addition, the translucent electrode 15 preferably has excellent conductivity in order to diffuse current uniformly over the entire surface of the p-type semiconductor layer 14.

As a constituent material of the translucent electrode 15, any one of conductive oxide containing any one of In, Zn, Al, Ga, Ti, Bi, Mg, W, and Ce, zinc sulfide, or chromium sulfide is used. A translucent conductive material selected from the group consisting of: As the conductive oxide, ITO (indium tin oxide (In ₂ O ₃ —SnO ₂ )), IZO (indium zinc oxide (In ₂ O ₃ —ZnO)), AZO (aluminum zinc oxide (ZnO—Al ₂ O)) ₃ )), GZO (gallium zinc oxide (ZnO—Ga ₂ O ₃ )), fluorine-doped tin oxide, titanium oxide and the like.

  Moreover, the structure of the translucent electrode 15 may be any structure including a conventionally known structure. The translucent electrode 15 may be formed so as to cover almost the entire surface of the p-type semiconductor layer 14, or may be formed in a lattice shape or a tree shape with a gap.

(P-type bonding pad electrode 16)
The p-type bonding pad electrode 16 also serves as a bonding pad, and is laminated on the translucent electrode 15. As the p-type bonding pad electrode 16, various compositions and structures are known, and these known compositions and structures can be used without any limitation, and can be provided by conventional means well known in this technical field.
The p-type bonding pad electrode 16 can be formed anywhere as long as it is on the translucent electrode 15. For example, it may be formed at a position farthest from the n-type electrode 17 or may be formed at the center of the semiconductor light emitting device 1. However, if it is formed at a position too close to the n-type electrode 17, it is not preferable because a short circuit between wires and balls occurs when bonding.

  Also, the electrode area of the p-type bonding pad electrode 16 is as large as possible to facilitate the bonding operation, but it prevents the emission of light emission. For example, when a large area exceeding half of the area of the chip surface is covered, the extraction of light emission is hindered, and the output is significantly reduced. Conversely, if the electrode area of the p-type bonding pad electrode 16 is too small, the bonding operation becomes difficult and the product yield is reduced. Specifically, it is preferably slightly larger than the diameter of the bonding ball, and generally has a circular shape with a diameter of 100 μm.

(Protective film layer)
The protective film layer (not shown) includes the upper surface and side surfaces of the translucent electrode 15, the exposed surface 20a of the n-type semiconductor layer 12, the side surfaces of the light-emitting layer 13 and the p-type semiconductor layer 14, the n-type electrodes 17 and p as required. It is formed so as to cover the side surface and the peripheral portion of the mold bonding pad electrode 16. By forming the protective film layer, it is possible to prevent moisture and the like from entering the semiconductor light emitting element 1 and to suppress the deterioration of the semiconductor light emitting element 1.
As the protective film layer, it is preferable to use an insulating material having a transmittance of 80% or more at a wavelength in the range of 300 to 550 nm. For example, silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), niobium oxide (Nb ₂ O ₅ ), tantalum oxide (Ta ₂ O ₅ ), silicon nitride (Si ₃ N ₄ ), aluminum nitride (AlN), or the like can be used. Among these, SiO ₂ and Al ₂ O ₃ are more preferable because a dense film can be easily formed by CVD film formation.

Hereinafter, a method for manufacturing the semiconductor light emitting device 1 will be described in detail with reference to the drawings as appropriate.
The drawings referred to in the following description are for explaining the present invention, and the size, thickness, dimensions, and the like of each part shown in the drawings are different from the actual dimensional relationship of the semiconductor light emitting device 1.

  In the manufacturing method of the semiconductor light emitting device 1 shown in FIG. 1 of the present invention, first, the laminated semiconductor layer 20 shown in FIG. 2 is manufactured. The method for manufacturing the stacked semiconductor layer 20 includes a first step of stacking the first n-type semiconductor layer 12c on the substrate 11, a regrowth layer 12d of the first n-type semiconductor layer 12c on the first n-type semiconductor layer 12c, The n-cladding layer 12b (second n-type semiconductor layer), the light-emitting layer 13, and the p-type semiconductor layer 14 are sequentially stacked, and the second step is then schematically configured. Hereafter, each process is demonstrated in detail using FIG.

<First step>
First, a substrate 11 made of sapphire or the like is prepared.
Next, the substrate 11 is placed in a growth chamber of a first MOCVD apparatus (first metal organic chemical vapor deposition apparatus), and a buffer layer 21 and a base layer 22 are sequentially stacked on the substrate 11 by MOCVD.

(First n-type semiconductor layer 12c stacking step)
Next, a first n-type semiconductor layer 12c (first n-type semiconductor layer) constituting a part of the n-contact layer 12a is stacked on the base layer 22. At this time, the film thickness of the first n-type semiconductor layer 12c is preferably 0.5 μm to 5 μm, and particularly preferably 2 μm to 4 μm. This is because the crystallinity of the semiconductor layer can be favorably maintained by setting the film thickness within the above range.

Moreover, when growing the 1st n-type semiconductor layer 12c, it is preferable to make substrate temperature into the range of 1000 to 1100 degreeC by hydrogen atmosphere.
Further, as a raw material for growing the first n-type semiconductor layer 12c, an organic metal raw material of a group III metal such as trimethyl gallium (TMG) and a nitrogen raw material such as ammonia (NH ₃ ) are used. A group III nitride semiconductor layer is deposited. The pressure in the growth chamber of the MOCVD apparatus is preferably 15 to 80 kPa, and more preferably 15 to 60 kPa. The carrier gas may be only hydrogen gas or a mixed gas of hydrogen gas and nitrogen gas.

  Thereafter, the substrate 11 on which each layer from the growth chamber of the first metal organic chemical vapor deposition apparatus (first MOCVD apparatus) to the first n-type semiconductor layer 12c of the n contact layer 12a is formed is taken out.

<Second step>
The second step further includes a step of forming a regrown layer 12d of the first n-type semiconductor layer 12c on the first n-type semiconductor layer 12c, and a step of forming an n-clad layer 12b (second n-type semiconductor layer). , And the step of forming the light emitting layer 13 and the step of forming the p-type semiconductor layer 14. Details will be described below.

(Step of forming regrowth layer 12d)
First, the substrate 11 on which the layers up to the first n-type semiconductor layer 12c are formed is placed in a growth chamber of a second metal organic chemical vapor deposition apparatus (second MOCVD apparatus). Next, a regrowth layer 12d of the first n-type semiconductor layer 12c is formed on the first n-type semiconductor layer 12c by MOCVD.

  In the present embodiment, before forming the regrowth layer 12d, the substrate 11 on which the layers up to the first n-type semiconductor layer 12c are formed is subjected to a heat treatment temperature of 500 ° C. to 1200 ° C. in an atmosphere containing nitrogen and ammonia, preferably Is preferably subjected to heat treatment (thermal cleaning) at 800 ° C. to 1100 ° C., more preferably 900 ° C. to 1000 ° C. The atmosphere of the heat treatment may be, for example, an atmosphere containing only nitrogen instead of the atmosphere containing nitrogen and ammonia. Note that an atmosphere containing only hydrogen is not preferable because the first n-type semiconductor layer 12c is decomposed and crystallinity is deteriorated. Further, the pressure in the growth chamber of the MOCVD apparatus at this time is preferably 15 to 100 kPa, and more preferably 60 to 95 kPa.

When such a heat treatment is performed, the substrate 11 on which the layers up to the first n-type semiconductor layer 12c of the n contact layer 12a are formed after the first step is completed from the growth chamber of the first metal organic chemical vapor deposition apparatus. Even if the surface of the first n-type semiconductor layer 12c is contaminated by being taken out, the contaminant can be removed before the regrowth layer 12d is formed. As a result, the crystallinity of the regrowth layer 12d is improved, and the crystallinity of the n-clad layer 12b and the light emitting layer 13 formed on the regrowth layer 12d is further improved.
If the surface of the first n-type semiconductor layer 12c remains contaminated, the reverse current (IR) may not be sufficiently low, and the electrostatic discharge (ESD) breakdown voltage may be insufficient. For this reason, the reliability of the semiconductor light emitting element 1 is lowered.

Further, in this embodiment, by supplying a dopant gas containing Si such as SiH ₄ together with the source gas of the regrowth layer 12d into the second metal organic chemical vapor deposition apparatus, the regrowth layer 12d is formed. Form. Further, this regrowth layer 12d formation step further includes step (1), step (2) and step (3), and in each case, a different amount of Si is supplied as a dopant, whereby the regrowth layer first layer is formed. Thus, a regrowth layer 12d having a configuration in which the second regrowth layer and the third regrowth layer are stacked can be formed.

When forming the regrowth layer 12d, step (1) may not be performed, but the film thickness of the regrowth layer 12d as a whole depends on the film thicknesses of the second and second regrowth layers. What is necessary is just to set suitably so that it may become an optimal value. In addition, the supply amount of the dopant gas in the step (1) is the same as that in forming the first n-type semiconductor layer 12c.
Further, the supply amount of the dopant gas in the step (2) is smaller than that in the formation of the first n-type semiconductor layer 12c (including a step in which Si is not supplied), but at the time of forming the first n-type semiconductor layer 12c. Is particularly preferably within a range of 0 to 1/15 times as large as.
Further, the supply amount of the dopant gas in the step (3) is larger than that in the formation of the first n-type semiconductor layer 12c, but is 1 to 4 times that in the formation of the first n-type semiconductor layer 12c. Is particularly preferred.

In addition, since it is not necessary to provide the step (1), the dopant gas may be supplied under the conditions of the step (2) from the first stage of the formation of the regrowth layer 12d.
Accordingly, the first regrowth layer having a film thickness of 0 μm to 2 μm containing about 5 × 10 ¹⁸ / cm ³ Si and the film thickness containing Si at a concentration of less than 1 × 10 ¹⁷ / cm ^3. A second regrowth layer having a thickness of 0.05 μm to 0.5 μm and a third regrowth layer having a thickness of 0.05 μm to 1 μm containing Si at a concentration of 5 × 10 ¹⁸ / cm ³ or more are formed. The

  At this time, by setting the Si concentration within the above range, the resistance of the second layer of the regrown layer is higher than that of the first layer of the regrown layer, while the crystallinity is higher than that of the first layer of the regrown layer. Become. Therefore, the flatness of the regrowth layer second layer surface is sufficiently high.

In addition, by setting the Si concentration within the above range, the resistance of the third layer of the regrown layer is lower than that of the first layer of the regrown layer.
However, the surface of the second layer of the regrown layer is formed to be sufficiently flat, and the third layer of the regrown layer is laminated thereon. Therefore, although the Si concentration is high, the generation of pits is suppressed, and the flatness of the surface of the third layer of the regrown layer is maintained.

As described above, the regrowth layer 12d having a configuration in which the regrowth layer first layer, the regrowth layer second layer, and the regrowth layer third layer are stacked is formed. When the Si concentration of the entire regrowth layer 12d is 1 × 10 ¹⁹ / cm ³ or more, there arises a problem that the reverse current IR increases and the electrostatic discharge (ESD) breakdown voltage is insufficient. However, in the present embodiment, by forming the third layer of the regrown layer on the second layer of the regrown layer, it is possible to prevent the reverse current IR from increasing and the electrostatic discharge (ESD) breakdown voltage shortage.

Further, when the Si concentration of the entire regrowth layer 12d is less than 1 × 10 ¹⁷ / cm ³ , the resistance becomes too high, so that the operating voltage of the semiconductor light emitting device 1 becomes high and the light emission is localized around the electrode. There was a problem to do. However, in the present embodiment, by forming the second regrowth layer in the regrowth layer 12d, an increase in the operating voltage of the semiconductor light emitting device 1 can be prevented, and the regrowth layer second layer can be prevented. Current can be spread in three layers.
Therefore, even for a high-current LED, it is possible to effectively prevent concentration of light emission points while preventing a decrease in light emission output.

  Further, when the regrowth layer 12d is grown, the substrate temperature is preferably in the range of 1000 ° C. to 1100 ° C. The substrate 11 on which the layers up to the first n-type semiconductor layer 12c are formed is taken out from the growth chamber of the first metal organic chemical vapor deposition apparatus, whereby the surface of the first n-type semiconductor layer 12c of the n-contact layer 12a. Even if the substrate is contaminated, the contaminant can be removed by setting the substrate temperature when the regrowth layer 12d is grown within the above range.

  As a result, the crystallinity of the n-clad layer 12b and the light emitting layer 13 formed on the regrowth layer 12d in the process described later can be made even better. On the other hand, if the substrate temperature when the regrowth layer 12d is grown is less than 1000 ° C., the reverse current (IR) may not be sufficiently lowered, or the electrostatic discharge (ESD) breakdown voltage may be insufficient. is there. Further, if the substrate temperature when the regrowth layer 12d is grown exceeds 1100 ° C., the surface flatness is deteriorated and the output of the semiconductor light emitting device 1 may be insufficient.

(Process for forming n-clad layer 12b (second n-type semiconductor layer))
Next, an n-clad layer 12b having a superlattice structure is formed on the regrowth layer 12d.
First, an n-side first layer (not shown) made of a group III nitride semiconductor having a thickness of 100 angstroms or less, and an n-side made of a group III nitride semiconductor having a thickness of 100 angstroms or less having a composition different from that of the n-side first layer. The second layer and the second layer are alternately stacked repeatedly in the number of 10 pairs (20 layers) to 40 pairs (80 layers). Further, in the present embodiment, Si is contained in the n-clad layer 12b at the same rate as that of the first n-type semiconductor layer 12c, for example, about 5 × 10 ¹⁸ / cm ³ .

(Light emitting layer 13 formation process)
Next, the light emitting layer 13 having a multiple quantum well structure is formed. First, the well layers 13b and the barrier layers 13a are alternately and repeatedly stacked. At this time, it is preferable to laminate so that the barrier layer 13a is arranged on the n-type semiconductor layer 12 side and the p-type semiconductor layer 14 side.
The composition and film thickness of the well layer 13b and the barrier layer 13a can be appropriately set so as to have a predetermined emission wavelength. Moreover, the growth temperature of the light emitting layer 13 can be 600-900 degreeC, and nitrogen gas can be used as carrier gas.

(P-type semiconductor layer 14 forming step)
The p-type semiconductor layer 14 may be formed by sequentially stacking a p-cladding layer 14a and a p-contact layer 14b. When the p-cladding layer 14a is a layer including a superlattice structure, a p-side first layer made of a group III nitride semiconductor having a thickness of 100 angstroms or less and a film having a composition different from that of the p-side first layer are used. What is necessary is just to laminate | stack repeatedly the p side 2nd layer which consists of a group III nitride semiconductor below thickness 100angstrom alternately.

The p contact layer 14b includes a p contact lower layer containing Mg at a concentration of about 1 × 10 ¹⁹ to 1 × 10 ²⁰ / cm ³ , and Mg 1 × 10 ²⁰ / cm ^{3 to} 3 × 10 ²⁰ / cm. It is particularly preferable that the p contact upper layer contained at a concentration of about ³ is stacked. Thereby, Mg can be contained at a high concentration in the portion (p contact upper layer) in contact with the translucent electrode 15, and the surface thereof can be formed flat. Therefore, the light emission output of the semiconductor light emitting element 1 can be further improved.
As described above, the laminated semiconductor layer 20 shown in FIG. 2 is manufactured.

Thereafter, the translucent electrode 15 is laminated on the p-type semiconductor layer 14 of the laminated semiconductor layer 20, and the translucent electrode 15 other than the predetermined region is removed by, for example, a generally known photolithography technique.
Subsequently, patterning is performed by a photolithography technique, for example, and a part of the laminated semiconductor layer 20 in a predetermined region is etched to expose a part of the first n-type semiconductor layer 12c of the n-contact layer 12a. An n-type electrode 17 is formed on the exposed surface 20a of 12a.
Thereafter, a p-type bonding pad electrode 16 is formed on the translucent electrode 15.
As described above, the semiconductor light emitting device 1 shown in FIG. 1 is manufactured.

According to the method for manufacturing the semiconductor light emitting device 1 of the present embodiment, the second regrowth layer containing Si at a concentration of less than 1 × 10 ¹⁷ / cm ³ can be formed in the step (2). Since the surface of the second regrowth layer has high flatness, the second regrowth layer containing Si at a concentration of 1 × 10 ¹⁹ / cm ³ or more on the second regrowth layer in step (3). Even if three layers are formed, deterioration of the flatness of the surface can be prevented. Therefore, the surface of the regrowth layer 12d on the light emitting layer 13 side can be formed flat.

In the present embodiment, the Si concentration of the third layer of the regrown layer can be increased, and the low-resistance regrown layer 12d can be formed. For this reason, it is possible to suppress an increase in the drive voltage Vf when a current is passed through the semiconductor light emitting element 1.
In addition, since the current can be diffused in the third layer of the regrown layer, even when a high current is applied to the light emitting element, it is possible to effectively prevent the concentration of the light emitting portion and prevent a decrease in the light emission output. Is possible.

As a result, the n-cladding layer 12b with good crystallinity can be formed on the regrown layer 12d, and the light-emitting layer 13 with good crystallinity can be formed on the n-cladding layer 12b.
Accordingly, the semiconductor light emitting device 1 having a sufficiently low reverse current (IR) and a high light emission output (Po) can be obtained. Moreover, it becomes possible to prevent the defect of the semiconductor light emitting element 1 and improve the LED chip yield within the standard.

<Lamp 3>
The lamp 3 of this embodiment includes the semiconductor light emitting device 1 of the present invention, and is a combination of the semiconductor light emitting device 1 and a phosphor. The lamp 3 of the present embodiment can have a configuration well known to those skilled in the art by means well known to those skilled in the art. For example, in the lamp 3 of this embodiment, a technique for changing the emission color by combining the semiconductor light emitting element 1 and the phosphor can be adopted without any limitation.

  FIG. 3 is a schematic cross-sectional view showing an example of a lamp including the semiconductor light emitting element 1 shown in FIG. The lamp 3 shown in FIG. 3 is a shell type, and the semiconductor light emitting element 1 shown in FIG. 1 is used. As shown in FIG. 3, the p-type bonding pad electrode 16 of the semiconductor light emitting device 1 is connected to one of the two frames 31 and 32 (the frame 31 in FIG. 3) by a wire 33. The semiconductor light emitting element 1 is mounted by connecting the mold electrode 17 (bonding pad) to the other frame 32 with a wire 34. Further, the periphery of the semiconductor light emitting element 1 is sealed with a mold 35 made of a transparent resin.

  Since the lamp 3 of the present embodiment uses the semiconductor light emitting element 1 described above, a high light emission output can be obtained.

  In addition, electronic devices such as backlights, mobile phones, displays, various panels, computers, game machines, and lighting incorporating the lamp 3 of the present embodiment, and mechanical devices such as automobiles incorporating such electronic devices are expensive. The semiconductor light emitting device 1 capable of obtaining a light emission output is provided. In particular, an electronic device driven by a battery such as a backlight, a mobile phone, a display, a game machine, and an illumination is preferable because an excellent product including the semiconductor light emitting element 1 that can obtain a high light emission output can be provided.

Hereinafter, the method for producing a semiconductor light emitting device of the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.
Example 1
The semiconductor light emitting device 1 shown in FIG. 1 was manufactured by the following method.
In the semiconductor light emitting device 1 of Example 1, a buffer layer 21 made of AlN, a base layer 22 made of undoped GaN having a thickness of 5 μm, and a first layer made of Si-doped n-type GaN having a thickness of 3 μm are formed on a substrate 11 made of sapphire. A structure in which an n-type semiconductor layer 12c, a 0.6 μm-thick regrown layer first layer, a 0.1 μm-thick regrown layer second layer, and a 0.1 μm-thick regrown layer third layer are stacked. A regrowth layer 12d made of n-type GaN having a thickness of 0.8 μm and an n contact layer 12a having a thickness of 3.8 μm were formed. Note that the Si doping concentration of the first n-type semiconductor layer 12c was 5 × 10 ¹⁸ / cm ³ .

Next, 20 nm (number of pairs) of a thin film layer consisting of a 2 nm thick n-side first layer made of GaInN and a 2 nm thick n side second layer made of GaN is repeatedly grown to a thickness of more than 80 nm. A multi-quantum well in which an n-cladding layer 12b having a lattice structure, a Si-doped GaN barrier layer having a thickness of 5 nm, and an In _0.15 Ga _0.85 N well layer having a thickness of 3.5 nm are stacked six times, and finally a barrier layer is provided. A light emitting layer 13 having a structure, a 20-nm-thick Mg-doped single layer Al _0.07 Ga _0.93 N p-cladding layer 14a, and a 150-nm-thick Mg-doped p-type GaN p-contact layer 14b were sequentially stacked. The p contact layer 14b is formed by laminating a p contact lower layer and a p contact upper layer. The p contact lower layer 14b contains Mg at a concentration of 5 × 10 ¹⁹ / cm ³ , and the p contact upper layer contains Mg 2 × 10 ²⁰ / The concentration was about cm ³ . The Si concentration of the n-clad layer 12b was 5 × 10 ¹⁸ / cm ³ . The thickness of the p contact upper layer was 20 nm.

  In this embodiment, the buffer layer 21, the base layer 22, and the first n-type semiconductor layer 12c are stacked using a first metal organic chemical vapor deposition apparatus (first MOCVD apparatus) (first process). The regrowth layer 12d, the n-clad layer 12b, the light-emitting layer 13, the p-clad layer 14a, and the p-contact layer 14b are stacked using a second metal organic chemical vapor deposition apparatus (second MOCVD apparatus) (second process). ). Here, before forming the regrown layer 12d, the substrate 11 on which the layers up to the first n-type semiconductor layer 12c are formed is subjected to heat treatment (thermal cleaning) at 950 ° C. in an atmosphere containing nitrogen and ammonia. It was. The regrown layer 12d was formed under the growth conditions shown below.

“Growth conditions for regrowth layer 12d”
The regrowth layer 12d was deposited on the first n-type semiconductor layer 12c using a group III metal organometallic material of trimethylgallium (TMG) and a nitrogen material such as ammonia (NH ₃ ). At this time, monosilane (SiH ₄ ) was used as the n-type doping gas. Further, the Si flow rate was adjusted to a predetermined concentration in each of the steps (1), (2), and (3). Further, the pressure in the MOCVD growth furnace when growing the regrown layer 12d was 40 kPa, the substrate temperature was 1080 ° C., and the carrier gas was all hydrogen.

Thereafter, a translucent electrode 15 made of ITO having a thickness of 200 nm was formed on the p-contact layer 14b by a generally known photolithography technique.
Next, etching was performed using a photolithography technique to form an exposed surface 20a of the n contact layer 12a in a desired region, and an n-type electrode 17 having a Ti / Au double layer structure was formed thereon.
Further, on the translucent electrode 15, a p-type bonding pad structure 16 having a three-layer structure composed of a metal reflective layer made of 200 nm Al, a barrier layer made of 80 nm Ti, and a bonding layer made of 1100 nm Au, It formed using the technique of photolithography.
As described above, the semiconductor light emitting device 1 of Example 1 shown in FIG. 1 was obtained.

In this way, the first regrowth layer having a thickness of 0.6 μm doped with Si at a concentration of 5 × 10 ¹⁸ / cm ³ and Si doped at a concentration of less than 1 × 10 ¹⁷ / cm ³ . A film thickness of a configuration in which a second regrowth layer having a thickness of 0.1 μm and a third regrowth layer having a thickness of 0.1 μm doped with Si at a concentration of 5 × 10 ¹⁸ / cm ³ are stacked. A regrown layer 12d made of 0.8 μm n-type GaN was formed.
As a result, the characteristics of the semiconductor light emitting device 1 were the forward voltage Vf = 3.0 V, the light emission output Po = 23 mW, and the reverse current IR (@ 20 V) = 0.1 μA.

(Example 2)
As a result of performing the same operation as in Example 1 except that the Si-containing concentration in the third layer of the regrown layer in Example 1 was changed to 1 × 10 ¹⁹ / cm ³ , the characteristics as the semiconductor light emitting device 1 were as follows. The direction voltage Vf was 3.0 V, the light emission output Po was 24 mW, and the reverse current IR (@ 20 V) was 0.1 μA.

Example 3
As a result of performing the same operation as in Example 1 except that the Si-containing concentration in the third layer of the regrown layer in Example 1 was changed to 2 × 10 ¹⁹ / cm ³ , the characteristics as the semiconductor light emitting device 1 were as follows. The direction voltage Vf was 3.0 V, the light emission output Po was 24 mW, and the reverse current IR (@ 20 V) was 0.1 μA.

Example 4
The film thickness of the first regrowth layer in Example 1 is 0.4 μm, the Si-containing concentration is 8 × 10 ¹⁸ / cm ³ , the film thickness of the second regrowth layer is 0.05 μm, and the Si-containing concentration is 1 ×. As a result of performing the same operation as in Example 1 except that 10 ¹⁷ / cm ³ , the thickness of the third layer of the regrowth layer was changed to 0.05 μm, and the Si-containing concentration was changed to 2 × 10 ¹⁹ / cm ^3. The characteristics of the light-emitting element 1 were a forward voltage Vf = 3.0 V, a light emission output Po = 23 mW, and a reverse current IR (@ 20 V) = 0.1 μA.

(Example 5)
The film thickness of the regrown layer first layer of Example 1 is 0.2 μm, the Si-containing concentration is 1 × 10 ¹⁹ / cm ³ , the film thickness of the second layer of the regrown layer is 0.2 μm, and the Si-containing concentration is 1 ×. As a result of performing the same operation as in Example 1 except that 10 ¹⁷ / cm ³ , the thickness of the third layer of the regrown layer was changed to 0.2 μm, and the Si-containing concentration was changed to 2 × 10 ¹⁹ / cm ^3. The characteristics of the light-emitting element 1 were a forward voltage Vf = 2.9 V, a light emission output Po = 23 mW, and a reverse current IR (@ 20 V) = 0.5 μA.

(Comparative Example 1)
In forming the regrowth layer, the same operation as in Example 1 was performed except that the regrowth layer 12d formed of a single layer having a thickness of 0.6 μm and a Si-containing concentration of 5 × 10 ¹⁸ / cm ³ was formed. As a result, the characteristics as the semiconductor light emitting device 1 were a forward voltage Vf = 3.2 V, a light emission output Po = 20 mW, and a reverse current IR (@ 20 V) = 1.0 μA.

Table 1 shows the results of forward voltage, light emission output (Po), and reverse current (IR) of the semiconductor light emitting devices of Examples 1 to 5 and Comparative Example 1.
The forward voltage Vf for the semiconductor light emitting devices 1 of the example and the comparative example is a voltage measured at a current application value of 20 mA by energization with a probe needle. Similarly, the light emission outputs (Po) for the semiconductor light emitting devices 1 of the example and the comparative example are each mounted in a TO-18 can package, and the light emission output at an applied current of 20 mA is measured by a tester. The reverse current (IR) is a value obtained by measuring a leakage current when a voltage of 20 V is applied to the light emitting element in the reverse direction.

As shown in Table 1, each of the semiconductor light emitting devices 1 of Examples 1 to 5 has a sufficiently low reverse current (IR), a relatively low forward voltage, and a light emission output (Po) of 20 mW or more. Thus, the brightness was high and the power consumption was low.
On the other hand, in Comparative Example 1 in which the thickness of the regrowth layer 12d is 0.6 μm, the Si-containing concentration is 5 × 10 ¹⁸ / cm ³ , and the concentration is uniform, compared with Examples 1 to 5. The light emission output (Po) was low, the forward voltage was relatively high, and the leakage current (reverse current (IR) was large.

  Moreover, about the semiconductor light emitting element 1 of Examples 1 to 5 and the comparative example, power efficiency η (%) in the range of applied current 20 to 100 mA {light emission output (mW) / (forward voltage (V) × applied current (MA))} was calculated. The results are shown in Table 2 and FIG.

  As these show, it is clear that in Examples 1 to 5, the power efficiency in the range of the applied current of 20 to 100 mA is superior to that of Comparative Example 1.

Moreover, the light emission output (Po; mW) in the range of applied current 20-100 mA was measured about the semiconductor light emitting element 1 of Example 1- Example 5 and the comparative example. The result is shown in FIG. As shown in FIG. 5, in Examples 1 to 5, it is clear that the light emission output (Po) in the range of applied current of 20 to 100 mA is superior to that of Comparative Example 1.
Further, in Comparative Example 1, the effect of improving the light emission output by increasing the applied current is reduced as the applied current is increased. As the applied current is increased, Examples 1 to 5 and Comparative Example are increased. The difference in light emission output (Po) from 1 is large.

  As described above, the semiconductor light-emitting elements 1 of Examples 1 to 5 can effectively improve the light-emission output, and the light-emission output has a smaller reverse current and a higher light output than the semiconductor light-emitting element 1 of Comparative Example 1. It was confirmed that In addition, it is confirmed that the light emission output can be effectively improved by applying a large current, and that a high light emission output can be obtained by applying a large current compared to the semiconductor light emitting device of Comparative Example 1. did it.

  Thus, in the method for manufacturing a semiconductor light emitting device of the present invention, as described above, in the step of laminating the regrowth layer, the growth conditions for the regrowth layer are the same as those for forming the first n-type semiconductor layer. And a step of supplying a smaller amount of Si as a dopant than when forming the first n-type semiconductor layer (including a step of not supplying Si) than when forming the first n-type semiconductor layer. 2) and the step (3) of supplying a larger amount of Si as a dopant than in the formation of the first n-type semiconductor layer in this order were able to effectively improve the light emission output. . In addition, even when a large current is applied, high luminous efficiency is obtained, and it has excellent characteristics for lighting applications that require a large current application.

  In addition, the higher the dopant concentration in the regrowth layer, the lower the resistance, but the lowering of crystallinity and the flatness of the regrowth layer surface are often worse, and the lower the dopant concentration, the higher the crystallinity. However, there is a problem that the resistance becomes high. However, according to the manufacturing method of the present invention, the deterioration of the flatness of the surface of the regrown layer 12d is prevented, and a light emitting layer (MQW layer) or a p-type semiconductor layer having high crystallinity is grown on the surface of the regrown layer. Therefore, it is possible to obtain an LED chip within the standard with high yield.

DESCRIPTION OF SYMBOLS 1 ... Semiconductor light emitting element, 3 ... Lamp, 12 ... N type semiconductor layer, 12a ... N contact layer, 12b ... N clad layer (2nd n type semiconductor layer), 12c ... 1st n type semiconductor layer, 12d ... Re-growth Layer, 13 ... light emitting layer, 14 ... p-type semiconductor layer

Claims (16)

In the first organometallic chemical vapor deposition apparatus, a first step of laminating a first n-type semiconductor layer on a substrate;
In a second metal organic chemical vapor deposition apparatus different from the first metal organic chemical vapor deposition apparatus, a regrowth layer of the first n type semiconductor layer and a second n type semiconductor layer are formed on the first n type semiconductor layer. And a second step of sequentially laminating a light emitting layer, a p-type semiconductor layer composed of a p-cladding layer and a p-contact layer,
In the step of laminating the regrowth layer,
The first n-type you supply semiconductor layer formed when a small amount of Si than as a dopant, or thickness was contained at a concentration of less than 1 × ¹⁰ 17 / cm ³ of Si without supplying 0.05Myuemu～0. A step (2) of laminating a second regrowth layer of 5 μm ;
A film thickness of 0.05 μm to 1 μm in which Si is supplied as a dopant in the same amount or a larger amount than when forming the first n-type semiconductor layer and Si is contained at a concentration of 5 × 10 ¹⁸ / cm ³ or more. A step (3) of laminating a third layer of a regrown layer ;
Are performed in this order. A method for manufacturing a semiconductor light emitting element.   2. The method of manufacturing a semiconductor light emitting element according to claim 1, wherein the regrowth layer is formed by supplying a dopant gas containing Si together with a source gas of the regrowth layer.   3. The method for manufacturing a semiconductor light emitting element according to claim 1, wherein the step (2) is started simultaneously with or in the middle of the formation of the regrowth layer.   The supply amount of the dopant gas in the step (2) is 0 to 1/15 times that in forming the first n-type semiconductor layer, and the supply amount of the dopant gas in the step (3) is the first n-type semiconductor layer. 4. The method for manufacturing a semiconductor light-emitting element according to claim 1, wherein the manufacturing method is 1 to 4 times that at the time of formation.   The method of manufacturing a semiconductor light emitting element according to claim 1, wherein the regrowth layer has a thickness of 0.1 μm to 3.5 μm. The step of laminating the regrowth layer includes a step (1) in which the growth condition of the regrowth layer is set to the same condition as that for forming the first n-type semiconductor layer before the step (2). the method of manufacturing a semiconductor light emitting device according to claim 1 to 5,. The process is characterized in Rukoto forming form a regrown layer first layer of thickness 2μm or less in the (1), a method of manufacturing a semiconductor light emitting device according to claim 6. The p contact layer is formed by laminating a p contact lower layer and a p contact upper layer, and Mg is contained in the p contact lower layer at a concentration of about 1 × 10 ¹⁹ to 1 × 10 ²⁰ / cm ³ , the method of manufacturing a semiconductor light emitting device according to claim 1 to 7, characterized in that p is contained in a concentration of about ^{1 × 10 20 / cm 3 ~3} × 10 20 / cm 3 the Mg in the contact layer. A first n-type semiconductor layer laminated on a substrate in a first organometallic chemical vapor deposition apparatus, and a second organometallic chemical vapor deposition apparatus different from the first organometallic chemical vapor deposition apparatus, A semiconductor light emitting device in which a regrowth layer of the first n-type semiconductor layer, a second n-type semiconductor layer, a light emitting layer, a p-type semiconductor layer comprising a p-cladding layer and a p-contact layer are laminated,
The regrown layer than said first n-type semiconductor layer rather small, Si content, Si is contained at a concentration of less than 1 × ¹⁰ 17 / cm ^3, the film thickness is 0.05μm~0.5μm a regrown layer the second layer, the Si content than the first n-type semiconductor layer is rather multi, Si is contained at a concentration of 5 × ¹⁰ 18 / cm ³ or more, the film thickness is 0.05μm~1μm the semiconductor light emitting device and the regrown layer third layer is characterized by a stacked in this order. The regrowth layer has a structure in which a regrowth layer first layer having the same Si content as that of the first n-type semiconductor layer is laminated on the opposite side of the regrowth layer third layer of the second regrowth layer. The semiconductor light-emitting device according to claim 9 , wherein the semiconductor light-emitting device is provided. Wherein among the regrown layer, the semiconductor light emitting device according to claim 1 0, wherein the regrown layer first layer is made form a thickness below 2μm or less. The device according to claim 9 to 1 1 the thickness of the regrowth layer is characterized in that it is a 0.1Myuemu～3myuemu. The p contact layer is formed by stacking a p contact lower layer and a p contact upper layer, and Mg is contained in the p contact lower layer at a concentration of about 1 × 10 ¹⁹ to 1 × 10 ²⁰ / cm ^3. the device according to claim 9 or 1 2, characterized in that the Mg in the upper layer is contained at a concentration of ^{1 × 10 20 / cm 3 ~3} × 10 20 / cm 3. Lamp comprising the semiconductor light emitting element according to any one of claims 9 to 1 3. Electronic apparatus, characterized in that the lamp is incorporated according to claim 1 4. Mechanical apparatus characterized by the electronic device is incorporated according to claim 1 5.

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