JP4089194B2 - Nitride semiconductor light emitting diode - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a nitride semiconductor light emitting diode, and more particularly to a nitride semiconductor light emitting diode in which a light transmissive electrode made of a metal thin film is provided on a light emitting surface.
[0002]
[Prior art]
Nitride semiconductors have been put to practical use as various light sources such as full-color LED displays, traffic signal lights, and image scanner light sources, as materials for light emitting diodes (LEDs) that exhibit blue or green color. In addition, when a blue LED using a gallium nitride compound is combined with a phosphor emitting yellow fluorescence, a white LED can be obtained. White LEDs are expected as an alternative light source for existing white fluorescent lamps by taking advantage of the characteristics of LEDs such as long life and low power consumption, and high external quantum efficiency is required.
[0003]
The gallium nitride compound semiconductor light-emitting diode has a problem that the light-emitting portion becomes strong in the vicinity of the opaque p-electrode because the sheet resistance of the p-type gallium nitride compound semiconductor layer is large. In order to solve this problem, a light-transmitting p-electrode made of a metal thin film is formed on the surface of the p-type gallium nitride compound semiconductor layer to achieve uniform light emission. A current flows through the entire surface of the translucent p electrode, and emitted light is transmitted through the translucent p electrode and extracted outside.
In addition, International Publication No. WO01 / 041223 discloses an LED 10 in which a second contact 19 having conductive fingers 20a and 20b is formed on a side (see FIG. 2). The conductive fingers 20a and 20b extend along the side where the contact 19 is formed and the side orthogonal to the side. The distance between the conductive fingers 20a and 20b and the edge of the conductive layer 18 is large on the side where the contact 19 is formed, and is small on the side perpendicular to the side.
[0004]
[Problems to be solved by the invention]
Therefore, it is desired that the translucent p-electrode has a sheet resistance as low as possible and a light transmittance as high as possible. However, if the film thickness is increased in order to reduce the sheet resistance, the light transmittance is lowered. If the light transmittance is increased, the sheet resistance is increased, so that it is difficult to realize at the same time. Accordingly, an object of the present invention is to form a gallium nitride-based compound semiconductor light-emitting diode in which the sheet resistance of the translucent p-electrode and the light transmittance are harmonized so that the external quantum efficiency is the best.
[0005]
[Means for Solving the Problems]
The gallium nitride-based compound semiconductor light-emitting diode of the present invention focuses on the sheet resistance relationship between the light-transmitting p-electrode and the n-type contact layer in optimizing the light-transmitting p-electrode. An n-type gallium nitride compound semiconductor layer having a contact layer with an n-type impurity concentration of 10 ¹⁷ to 10 ²⁰ / cm ³ and a p-type impurity concentration of 10 ¹⁷ to 10 ²⁰ // are formed on the n-type gallium nitride compound semiconductor layer. an active layer having a quantum well structure sandwiched between a p-type gallium nitride compound semiconductor layer having a contact layer of cm ³ , an n-type gallium nitride compound semiconductor layer and a p-type gallium nitride compound semiconductor layer, and an n-type An n-electrode formed on the contact layer of the gallium nitride-based compound semiconductor layer; a translucent p-electrode composed of a metal thin film formed on substantially the entire contact layer of the p-type gallium nitride-based compound semiconductor layer; and a translucent p A gallium nitride-based compound semiconductor light emitting diode having a wire bonding base electrode formed on the electrode, wherein the translucent p-electrode is made of gold And a metal electrode comprising one selected from the group of platinum group elements, and is a film thickness is 200Å or less, a contact layer of n-type gallium nitride compound layer is a thickness 4 to 6 [mu] m, the n electrode is formed in the corner portion of the light-emitting diodes, the base electrodes are arranged in opposite corners on the n electrode, and at least 20μm or more from the edge of the p-type gallium nitride-based compound semiconductor layer on the light transmitting p electrode extension conductive portions of two or more linear apart are formed, the extension conductive portion and said arcuate linear der Rukoto contacting the edge and recently tip.
[0007]
Further, the sheet resistance R _p of the transparent p-electrode is formed so as to be 10 [Omega / □ or more, R _p ≧ R _n to become the sheet resistance n-type gallium nitride-based with a R _n compound semiconductor layer is compared It is preferable because it can be easily created. Moreover, it is preferable that the film thickness of the translucent p-electrode is 200 mm or less because the light transmittance is improved sharply and the external quantum efficiency is remarkably improved as compared with the case of 300 mm or more.
[0008]
Further, when the translucent p-electrode is formed of a multilayer film or an alloy composed of one kind selected from the group of gold and platinum group elements and at least one other element, the translucent p-electrode The sheet resistance is preferably adjusted according to the contents of the gold and platinum group elements. This is because gold and platinum group elements have a high absorption coefficient in a short wavelength region of blue to green, and thus the light transmittance is improved as the content is smaller. The sheet resistance is preferably adjusted by adjusting the content of the gold or platinum group element.
[0009]
As described above, the feature of the present invention is to balance the translucent p-electrode and the sheet resistance of the n-side contact layer, and as a result, to exhibit the effect of improving the external quantum efficiency. Can do. In an actual gallium nitride-based compound semiconductor light emitting diode, a predetermined pedestal electrode is formed on the translucent p-electrode.
[0010]
In the gallium nitride compound semiconductor light-emitting diode of the present invention, when the n-type electrode is formed in a strip shape along the side of the light-emitting diode, the pedestal electrode is preferably formed in parallel with the n-type electrode. By forming the pedestal electrode and the n electrode in parallel, the current density tends to be uniform on and inside a quadrangular side having the pedestal electrode and the n electrode facing each other.
[0011]
In the gallium nitride-based compound semiconductor light-emitting diode of the present invention, when the n-type electrode has a shape other than a belt shape such as a substantially rectangular shape or a circular shape near one side of the light-emitting diode, the diode of the diode provided with the n-type electrode is used. A pedestal electrode may be provided in the vicinity of the side facing the side. The shape of the pedestal electrode is not particularly limited, and is formed in a band shape, a substantially rectangular shape, a circular shape, or the like. Since the n-type electrode can have a smaller area than that formed in a strip shape, it is possible to reduce the cut-out area of the light emitting surface for exposing the n-type layer. Here, when the pedestal electrode is formed in a circular shape, a substantially rectangular shape, or the like, the pedestal peripheral portion that emits strong light is reduced as compared with the pedestal electrode formed in a band shape. Therefore, it is preferable to provide an extended conductive portion from the pedestal electrode to increase the strong light emitting region. In this case, the extended conductive portion is preferably formed so that the distance between the n electrode and the pedestal electrode is as uniform as possible.
[0012]
In the gallium nitride-based compound semiconductor light-emitting diode of the present invention, when the n-type electrode is formed at the corner of the light-emitting diode, the form in which the pedestal electrode is formed at the corner of the light-emitting diode facing the n-electrode is also preferable. Furthermore, the pedestal electrode may be formed into a shape provided with two or more extended conductive portions. If the current can be expanded in a fan shape from the pedestal electrode at the corner, the light emitting region becomes wider. For this reason, it is preferable that at least two or more extended conductive portions extending around the corner base electrode are formed.
[0013]
Further, if the distance between the base electrode and the n electrode is to be formed as equal as possible, it is not desirable that the extended conductive portion is formed in parallel with the side portion. In particular, it is more preferable that the extended conductive portion is formed in a circular arc shape centering on the n electrode. Also. At this time, if an extended conductive portion having an excessive area is formed, the light shielding effect is increased, which is not preferable. Therefore, the pedestal electrode may be suppressed to a necessary minimum area.
[0014]
More preferably, the extended conductive portion is formed away from the edge of the p-type gallium nitride compound semiconductor layer. When the extended conductive portion is formed at the edge of the p-type gallium nitride compound semiconductor layer, a part of the range that can be a strong light emitting region is removed from the p-type gallium nitride compound semiconductor layer, thereby reducing the external quantum efficiency. become.
[0015]
When separating the extended conductive part and the side of the light-emitting diode, the distance should be set so that the part that emits considerably strong light does not cover the side, considering that the external quantum efficiency is not impaired. Is preferred. The extended conductive portion and the edge of the p-type gallium nitride compound semiconductor are separated so that at least a region having an intensity of 90% or more with respect to the maximum emission intensity falls within the range of the p-type gallium nitride compound semiconductor layer. Preferably it is formed. However, if the distance between the extended conductive portion and the side portion is too large, a non-light-emitting or weak light-emitting region that does not contribute much to the external quantum efficiency is included between them, and as a result, the external quantum efficiency is lowered. Therefore, the extended conductive portion is separated from the edge of the p-type gallium nitride compound semiconductor so that the emission intensity of the edge of the p-type gallium nitride compound semiconductor is 100% or less and 80% or more with respect to the maximum emission intensity. More preferably, it is arranged.
[0016]
Alternatively, the distance between the extended conductive portion and the edge of the p-type gallium nitride compound semiconductor may be at least 20 μm, more preferably 20 μm or more and 50 μm or less.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
[Embodiment 1]
FIG. 1 is a cross-sectional view of a gallium nitride compound semiconductor light emitting diode according to the present invention. The gallium nitride compound semiconductor light-emitting diode 1 is n-type on a sapphire substrate 10 via a low-temperature growth buffer layer (not shown) made of GaN or Al _x Ga _{1- x} N (0 ≦ x <1). An n-type contact layer 11 and an n-type gallium nitride compound semiconductor layer 12 made of a gallium nitride compound semiconductor are formed. On top of that, an active layer 13 having a quantum well structure and a p-type gallium nitride compound semiconductor layer 14 are formed.
[0018]
The sheet resistance of the n-type contact layer 11 formed at an impurity concentration of 10 ¹⁷ to 10 ²⁰ / cm ³ and the sheet resistance of the translucent p-electrode 15 are formed in a relationship of R _p ≧ R _n . The n-type contact layer 11 is preferably formed to a thickness of 4 to 6 μm, for example, and its sheet resistance is estimated to be 15 to 10 Ω / □, so that the R _{p at} this time is formed as a thin film of 10 Ω / □ or more. Good. The translucent p-electrode 15 may be formed of a thin film having a thickness of 200 μm or less.
[0019]
Further, when the translucent p-electrode is formed of a multilayer film or an alloy composed of one kind selected from the group of gold and platinum group elements and at least one other element, the translucent p-electrode The adjustment of the sheet resistance of 15 may be made by the content of the contained gold or platinum group element. Since the gold or platinum group element has a high absorption coefficient in the wavelength region of the gallium nitride compound semiconductor light emitting diode 1 of the present invention, the smaller the amount of gold or platinum group element contained in the translucent p-electrode, the more light-transmitting. Get better. Although the relationship of sheet resistance in the conventional light emitting diode is R _p <R _n , in the present invention, since R _p ≧ R _n , the sheet resistance of the translucent p electrode 15 is formed high. That is, the translucent p-electrode is formed in a thin film as compared with the conventional one, but at this time, it is preferable to reduce the thickness by reducing the content of gold or platinum group elements.
[0020]
In the light emitting diode of the present invention, the sheet resistance R _n Omega / □ of the n-type contact layer 11, the sheet resistance R _p Omega / □ and transparent p-electrode 15, so as to have a relationship of R _p ≧ R _n It is formed. It is difficult to measure R _n after forming as a light emitting diode, and it is practically impossible to know the relationship between R _p and R _n , but from the state of light intensity distribution at the time of light emission, what R _p and it is possible to know and has a relationship with the R _n.
[0021]
FIG. 2 is a top view of an embodiment of the present invention. A portion of the p-type gallium nitride compound semiconductor layer 14 along one side of the substrate is cut away to expose the n-type contact layer 11, and an n-electrode 17 is formed in a strip shape on the exposed n-type contact layer 11. . A translucent p-electrode 15 made of a metal thin film is formed on almost the entire upper surface of the p-type gallium nitride-based compound semiconductor layer 14 that is left uncut, and an n-electrode is formed on the translucent p-electrode 15. A pedestal electrode 16 is formed in parallel with the pedestal.
[0022]
[Embodiment 2]
In another embodiment, the light-emitting diode satisfies the relationship of R _p ≧ R _n , and the pedestal electrode 16 and the n-electrode 17 are arranged on the sides of the element as shown in FIG. Good. The n-electrode 17 is formed in a shape other than a band shape, for example, a circle or a substantially rectangle. The base electrode 16 may have any shape such as a band shape, a circle shape, or a substantially rectangular shape. Since the area of the n-type electrode 17 can be made smaller than that formed in a band shape, the cut-out area of the light emitting surface for exposing the n-type layer can be reduced, and the effect of suppressing excessive reduction of the light emitting area can be suppressed. There is. Further, when the pedestal electrode 16 is formed in a circular shape, a substantially rectangular shape, or the like, there is an advantage in that the light shielding region by the opaque pedestal electrode is reduced as compared with the case where the pedestal electrode 16 is formed in a band shape, but the strong light emitting region is reduced because the outer periphery of the pedestal is reduced. It also has the disadvantage of being. Therefore, it is preferable to provide a linearly extending conductive portion from the base electrode 16 to increase the strong light emitting region by extending the outer periphery.
[0023]
When the translucent p-electrode 15 and the n-type contact layer 11 have a relationship of R _p ≧ R _n , further improvement in external quantum efficiency is expected when the base electrode 16 having the extended conductive portion 106 is used. Although the pedestal electrode 16 shown in FIGS. 3B to 3E is a part of a preferred form, the shape is not limited to this, and the outer periphery of the pedestal electrode 16 is long, the light shielding region by the pedestal electrode 16 is narrow, and the n-electrode 17 If it is formed so that the distance between and becomes equal, it can be a preferable form. Only when the light emitting diode satisfies the relationship of R _p ≧ R _n, the light emitting diode that satisfies the above three conditions is a light emitting diode that emits strong light and easily emits light uniformly. Since it is difficult to completely satisfy these three conditions, it is not necessary to satisfy all of them, and it is preferable to satisfy the conditions in a well-balanced manner. In order to reduce the light shielding region, the extended conductive portion 106 is preferably linear, but in order to lengthen the outer periphery of the base electrode 16, a mesh shape is also preferable. Further, the shape may be a curved shape, a lattice shape, or a branch shape in addition to the linear shape as shown in FIG.
[0024]
The extended conductive portion 106 can be formed at various positions. However, in order not to reduce the external quantum efficiency, the extended conductive portion 106 is preferably formed away from the edge of the p-type gallium nitride compound semiconductor layer 14. A strong light emitting region appears around the extended conductive portion around the extended conductive portion, and shows a light emission distribution in which the emission intensity decreases as the distance from the extended conductive portion increases. Forming the extended conductive portion 106 at the edge of the p-type gallium nitride compound semiconductor layer 14 is not preferable because the light-emitting range protrudes from the p-type gallium nitride compound semiconductor layer 14 and leads to a decrease in the light emitting region. . Therefore, it is preferable to form the extended conductive portion 106 and the peripheral edge of the p-type gallium nitride compound semiconductor layer 14 so that the light emitting region does not protrude from the element.
[0025]
The distance between the extended conductive portion and the edge of the p-type gallium nitride compound semiconductor layer may be determined in consideration of not deteriorating the external quantum efficiency. Assuming that the maximum light emission intensity confirmed in the vicinity of the extended conductive portion 106 is 100%, the extended conductive portion and the light emitting diode are arranged so that at least a region having a light emission intensity of 90% or more does not protrude from the p-type gallium nitride compound semiconductor layer 14. It is preferable that it is formed apart from the side portion. However, if the distance is too great, a non-light emitting or weak light emitting region appears between the extended conductive portion and the edge, and the region is located on the side opposite to the n electrode 17 when viewed from the extended conductive portion 106. The current does not flow any further and becomes a light emission loss region. Therefore, the distance between the extended conductive portion and the edge of the p-type gallium nitride compound semiconductor is within the range of the emission intensity of 100% or less and 90% or more with respect to the maximum emission intensity of 100%. A distance that reaches the edge of the compound semiconductor layer 14 is more preferable.
[0026]
In the gallium nitride compound semiconductor light-emitting diode formed here, the distance between the extended conductive portion 106 and the edge of the p-type gallium nitride compound semiconductor layer 14 is preferably at least 20 μm or more, More preferably, it is formed to be 20 μm or more and 50 μm or less.
[0027]
[Embodiment 3]
In a further embodiment, as shown in FIG. 4A, the base electrode 16 and the n-electrode 17 may be arranged at the corners of the device facing each other. The pedestal electrode 16 is preferably an extended conductive portion 106. The pedestal electrode 16 shown in FIGS. 4B to 4E is a part of a preferred form, and may have other shapes. When the relationship of R _p ≧ R _n is satisfied, a light emitting diode having a long outer periphery of the pedestal electrode 16, a narrow light shielding region by the pedestal electrode 16, and an equal distance from the n electrode 17 emits strong light and emits light uniformly. It becomes a light emitting diode easy to be used. However, since it is difficult to form a pedestal electrode that has the long outer periphery of the pedestal electrode, the light-shielding area is small, and the distance between the n-electrode and the n-electrode is completely satisfied, it is not always necessary to meet the conditions perfectly. It is preferable that the two conditions are satisfied in a well-balanced manner. The shape of the extended conductive portion 106 may be linear, mesh, curved, lattice, or branched.
[0028]
Similar to the second embodiment, in the third embodiment, the extended conductive portion 106 can be formed at various positions. However, in order not to lower the external quantum efficiency, it is preferable that the edge of the p-type gallium nitride compound semiconductor layer 14 is formed apart from the extended conductive portion 106 so that a region with strong light emission does not protrude from the edge.
[0029]
Here, the extended conductive portion is formed such that the extended conductive portion and the side of the light emitting diode are separated so that a region having a light emission intensity of 90% or more with at least the maximum light emission intensity of 100 is not protruded from the edge. preferable. More preferably, it is formed in a region having a light emission intensity of 100% or less and 80% or more with a distance that overlaps the edge. This is preferable because the strong light-emitting region is not impaired and the region that does not emit light can be reduced. Alternatively, the extended conductive portion 106 and the edge of the p-type gallium nitride compound semiconductor layer 14 may be formed so as to be separated from each other by at least 20 μm or more, and more preferably formed such that the separation distance is 20 μm or more and 50 μm or less. It is to be done.
[0030]
【Example】
[Example 1]
A buffer layer (not shown) made of GaN is grown to a thickness of 200 angstroms at 500 ° C. on a sapphire substrate 10 having a 2 inch φ, (0001) C plane as a main surface, and then the temperature is set to 1050. An undoped GaN layer is grown to a thickness of 5 μm at a temperature of 0 ° C. Note that the film thickness to be grown is not limited to 5 μm, and it is desirable to grow the film thicker than the buffer layer and adjust the film thickness to 10 μm or less. Next, after the growth of the undoped GaN layer, the wafer is taken out of the reaction vessel, a striped photomask is formed on the surface of the GaN layer, and a SiO _{2 having a} stripe width of 15 μm and a stripe interval (window) of 5 μm is formed by a CVD apparatus. A mask 12 is formed with a thickness of 0.1 μm. After forming the mask, the wafer is set again in the reaction vessel, and undoped GaN 14 is grown to a thickness of 10 μm at 1050 ° C. The crystal defect of the undoped GaN layer 11 was 10 ¹⁰ / cm ² or more, but the crystal defect of the GaN layer was 10 ⁶ / cm ² or less.
[0031]
(N-type contact layer 11, n-type gallium nitride compound semiconductor layer 12)
Next, the n-type contact layer 11 and the n-side gallium nitride compound semiconductor layer 12 are formed. First, at 1050 ° C., the n-side contact layer 11 made of GaN doped with 4.5 × 10 ¹⁸ / cm ^{3 of} Si using TMG and ammonia gas as source gas and silane gas as impurity gas, has a thickness of 2.25 μm. Grow in. Next, the silane gas alone was stopped, and at 1050 ° C., TMG and ammonia gas were used to grow an undoped GaN layer with a film thickness of 75 Å. Subsequently, silane gas was added at the same temperature, and Si was added to 4.5 × 10 ¹⁸ / A cm ³ doped GaN layer is grown to a thickness of 25 Å. In this way, a pair consisting of an A layer composed of an undoped GaN layer of 75 angstroms and a 25 angstrom B layer having an Si doped GaN layer is grown. Then, 25 pairs are stacked so as to have a thickness of 2500 Å, and an n-side gallium nitride compound semiconductor layer made of a multilayer film having a superlattice structure is grown.
[0032]
(Active layer 13)
Next, a barrier layer made of undoped GaN is grown to a thickness of 250 Å, and subsequently the temperature is set to 800 ° C., and a well layer made of undoped In _0.3 Ga _0.7 N is formed to a thickness of 30 Å using TMG, TMI, and ammonia. Grow with thickness. Then, an active layer 13 having a multiple quantum well structure having a total film thickness of 1930 angstroms is formed by alternately laminating seven barrier layers and six well layers in the order of barrier + well + barrier + well. Grow.
[0033]
(P-type layer 14)
Next, a p-type layer 14 composed of a p-side multilayer clad layer and a p-side contact layer is formed. First, a third nitride made of p-type Al _0.2 Ga _0.8 N doped with 1 × 10 ²⁰ / cm ^{3 of} Mg using TMG, TMA, ammonia, Cp ₂ Mg (cyclopentadienyl magnesium) at a temperature of 1050 ° C. A semiconductor layer is grown to a thickness of 40 angstroms, followed by a temperature of 800 ° C. and made of In _0.03 Ga _0.97 N doped with 1 × 10 ²⁰ / cm ^{3 of} Mg using TMG, TMI, ammonia, Cp ₂ Mg. A fourth nitride semiconductor layer is grown to a thickness of 25 angstroms. Then, these operations are repeated, and 5 layers are alternately stacked in the order of 3 + 4, and finally, the third nitride semiconductor layer is grown to a thickness of 40 angstroms and is formed of a superlattice multilayer film. A side multilayer cladding layer is grown to a film thickness of 365 angstroms. Subsequently, at 1050 ° C., a p-side contact layer made of p-type GaN doped with 1 × 10 ²⁰ / cm ^{3 of} Mg using TMG, ammonia, and Cp ₂ Mg is grown to a thickness of 700 Å.
[0034]
After completion of the reaction, the temperature is lowered to room temperature, and the wafer is annealed in a reaction vessel at 700 ° C. in a nitrogen atmosphere to further reduce the resistance of the p-type layer.
[0035]
Next, the wafer is taken out from the reaction vessel, a mask having a predetermined shape is formed on the surface, and etching is performed from the p-type gallium nitride compound semiconductor layer side with an RIE (reactive ion etching) apparatus, as shown in FIG. The surface of the n-side contact layer 11 is exposed at the corner of the element.
[0036]
(Translucent p-electrode 15, pedestal electrode 16, n-electrode 17)
After etching, a light-transmitting p-electrode 15 (Ni / Au = 60/70) having a thickness of 110 Å and a thickness of 0.5 μm are formed on the p-electrode 26 so as to cover almost the entire surface of the p-type layer 14. A base electrode 16 made of Au is formed. As shown in FIG. 5, the pedestal electrode 16 forms a pedestal electrode 16 having a substantially rectangular region for wire bonding and an arcuate line-shaped extended conductive portion 106 at a corner. The distance between the tip of the extended conductive portion that is closest to the side of the light emitting diode is 20 μm. On the other hand, a substantially rectangular n-electrode 17 containing W and Al was formed on the surface of the n-side contact layer 11 exposed by etching to obtain a light-emitting diode element.
[0037]
FIG. 6 shows the distribution of light emission intensity when the LED thus formed emits light. In the histogram of FIG. 6, the horizontal axis is the relative light emission intensity when the maximum light emission intensity of the measurement range is 1.0, and the vertical axis is a value proportional to the surface area of the LED that is the relative light emission intensity. Yes. Thus, the peak position shifts to the right, and the higher the peak height, the better the external quantum efficiency, and the narrower the peak width, the more uniform the emission intensity. FIG. 6 shows that the external quantum efficiency is increased because the peak position is shifted to the right and the height of the peak is higher than in FIG. 7 of the comparative example.
[0038]
[Comparative example]
The thickness of the translucent p electrode 15 was set to 260 angstroms (Ni / Au = 60/200), and the base electrode 16 was the same as that of Example 1 except that the extended conductive portion 106 was not formed. When light was emitted under the same conditions as in the example, the emission intensity distribution shown in FIG. 7 was shown.
[0039]
【The invention's effect】
In the present invention, by the relationship between the sheet resistance R _n of the sheet resistance R _p and n-type contact layer 11 of the transparent p-electrode 15 was set to be R _p ≧ R _n, and improved external quantum efficiency. Further, when such a sheet resistance relationship is established, it is possible to increase the strong light emitting region by lengthening the outer periphery of the base electrode.
[Brief description of the drawings]
FIG. 1 is a schematic cross-sectional view of a light-emitting diode according to the present invention.
FIG. 2 is a schematic diagram of an example of an embodiment of the present invention.
FIG. 3 is a schematic view of an example of an embodiment of the present invention.
FIG. 4 is a schematic diagram of an example of an embodiment of the present invention.
FIG. 5 is a schematic diagram of an embodiment of the present invention.
FIG. 6 is a histogram of light emission intensity distribution according to an embodiment of the present invention.
FIG. 7 is a histogram of emission intensity distribution of a comparative example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Substrate 11 ... n-type contact layer 12 ... n-type gallium nitride compound semiconductor layer 13 ... active layer 14 ... p-type gallium nitride compound semiconductor 15 ... translucent p Electrode 16 ... pedestal electrode 106 ... extended conductive portion 17 of pedestal electrode ... n electrode

Claims (4)

An n-type gallium nitride compound semiconductor layer having a contact layer with an n-type impurity concentration of 10 ¹⁷ to 10 ²⁰ / cm ³ and a p-type impurity concentration of 10 ¹⁷ to 10 ²⁰ formed on the n-type gallium nitride compound semiconductor layer. A p-type gallium nitride compound semiconductor layer having a / cm ³ contact layer, an active layer having a quantum well structure sandwiched between the n-type gallium nitride compound semiconductor layer and the p-type gallium nitride compound semiconductor layer, An n-electrode formed on the contact layer of the n-type gallium nitride compound semiconductor layer, and a translucent p-electrode comprising a metal thin film formed on substantially the entire contact layer of the p-type gallium nitride compound semiconductor layer; A gallium nitride compound semiconductor light emitting diode comprising a wire bonding base electrode formed on the translucent p-electrode,
The translucent p-electrode is made of a metal electrode containing one selected from the group of gold and platinum group elements, and has a film thickness of 200 mm or less,
The contact layer of the n-type gallium nitride compound layer has a thickness of 4 to 6 μm,
Wherein and n electrode is formed in a corner portion of the light emitting diode, said base electrode, the n electrode is disposed in a corner portion opposed to, and the translucent p SL before on the electrode p-type gallium nitride-based compound extension conductive portion from the side edge of at least 20μm or more apart two or more linear semiconductor layer is formed, the extension conductive portion and said arcuate linear der Rukoto contacting the edge and recently tip Gallium nitride compound semiconductor light emitting diode. Wherein the extension conductor portion and the base electrode, the distance between the n-electrode, a gallium nitride-based compound semiconductor light emitting diode according to claim 1, characterized in that it is substantially uniform. 3. The gallium nitride-based compound semiconductor light-emitting diode according to claim 1, wherein the extended conductive portion is formed to be separated from a side portion of the light-emitting diode element by 20 μm or more and 50 μm or less. . The pedestal electrode is circular or features to claims 1 to 3 or 1 gallium nitride-based compound semiconductor light emitting diode according to Section that substantially rectangular.

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