KR100926319B1 - Light emitting diode device having advanced light extraction efficiency and preparation method thereof - Google Patents

Abstract

The present invention (a) a light emitting diode unit is formed with an uneven pattern on the light emitting surface; And (b) an ohmic contact metal layer positioned in a recess part formed by etching a portion of the light emitting surface of the uneven patterned light emitting diode portion, and a method of manufacturing the same.

In the present invention, in order to increase the light extraction efficiency of the light emitting diode, instead of forming irregularities on the light emitting surface of the light emitting diode portion through wet etching after forming the electrode, an etching process and an electrode forming step after forming the uneven pattern on the light emitting surface By this, it is possible to provide corrosion prevention of the electrode material by the etching process and increase in light extraction efficiency of the light emitting diode device.

Ohmic contact metal, irregularities, etching, recess, light extraction, light emitting diode device

Description

LIGHT EMITTING DIODE DEVICE HAVING ADVANCED LIGHT EXTRACTION EFFICIENCY AND PREPARATION METHOD THEREOF}

Figure 1a is a schematic diagram showing the optical path in the light emitting surface of the light emitting diode portion is removed conventional sapphire substrate, Figure 1b is a schematic diagram showing the optical path in the light emitting surface formed with an uneven pattern of the light emitting diode portion from which the sapphire substrate is removed according to the present invention to be.

FIG. 2 is a cross-sectional structural view of a conventional light emitting diode device including an uneven patterned light emitting diode portion after forming an electrode on a light emitting surface of a gallium nitride based light emitting diode portion from which a sapphire substrate is removed.

3 is a sapphire substrate having an ohmic contact metal layer positioned in a recessed part formed by etching a portion of the light emitting diode portion having an uneven pattern formed on the light emitting surface and the uneven patterned light emitting surface according to the present invention. Section of a light emitting diode module chip.

4 is a schematic diagram of a manufacturing process of a light emitting diode device from which a sapphire substrate is removed according to the present invention.

FIG. 5 is a scanning electron microscope each showing a surface of an n-type layer exposed by re-etching a portion of the light emitting diode portion having unevenness formed on the light emitting surface by dry and wet etching methods and a part of the uneven patterned light emitting surface according to the present invention. scanning electron microscope (SEM).

According to the present invention, instead of forming irregularities on the light emitting surface of the light emitting diode portion through wet etching after forming the electrode, an etching process and an electrode are formed after the uneven pattern is formed on the light emitting surface, thereby causing corrosion of the electrode material by the etching process. The present invention provides a light emitting diode device which is prevented and has an increased light extraction efficiency and a method of manufacturing the same.

A light emitting diode (LED) device is a semiconductor device that generates light by flowing a current in a forward direction through a PN junction.

A sapphire substrate is mainly used for growing a gallium nitride compound semiconductor for manufacturing a light emitting diode. Since the sapphire substrate is an insulator, the anode and cathode of the light emitting diode are formed on the front surface of the wafer. A general low-power gallium nitride-based light emitting diode is fabricated by placing a sapphire substrate with a crystal structure on a lead frame and then connecting two electrodes to the top. In order to improve heat dissipation efficiency, the sapphire substrate is thinned to a thickness of about 100 μm or less and attached to the lead frame. At this time, the thermal conductivity of the sapphire substrate is about 50 W / m · K, and even if the thickness is about 100 μm, the thermal resistance is very large. On the other hand, in the case of high-output gallium nitride-based light emitting diodes, flip chip bonding is mainly used to improve heat dissipation characteristics.

In the flip chip bonding method, a chip in which a light emitting diode structure is formed is inverted and bonded to a submount such as a silicon wafer (150 W / m · K) or AlN ceramic (about 180 W / m · K) substrate having excellent thermal conductivity. Since the flip chip structure emits heat through the submount substrate, the heat dissipation efficiency is improved as compared with the heat dissipation through the sapphire substrate, but the manufacturing process is complicated and heat dissipation problems remain.

In order to solve these problems, fabrication of light emitting diodes from which the sapphire substrate has been removed has been attracting attention. This is a technology for packaging after removing the sapphire substrate from the gallium nitride-based light emitting diode crystal structure is known to have the best heat dissipation efficiency, it is known that the manufacturing process is significantly reduced and the light emitting area has a wide light emitting area.

Despite these advantages, however, light emitting diodes manufactured by sapphire substrate removal show lower light extraction efficiency compared to light emitting diodes using conventional technologies, for the following reasons. Due to the large difference in refractive index between the gallium nitride and the molding material, a large part of the light emitted from the light emitting diode is totally reflected without disappearing to the outside and proceeds to the light emitting diode structure again and disappears. When the light generated from the active layer is emitted to the outside, it is assumed to be totally reflected when it is larger than the critical angle. When calculating the refractive index of gallium nitride and the molding material, only about 10% of the generated light is emitted to the outside. Therefore, much improvement of light extraction efficiency is required. To solve this problem, some researchers are investigating how to remove the sapphire substrate with a laser, form electrode wirings, and apply irregularities to the exposed n-GaN surface. As a specific method of giving irregularities to the surface of n-GaN, a conical shape is formed on the n-GaN surface by wet etching (T. Fujii et al. Appl. phys. Lett., 2004, 84, 855, Y Gao et al. Jap. J. Appl. Phys., 2004, 43, L637). In this case, the light extraction efficiency is reported to be improved by about 2 times.

The principle of improving the light extraction efficiency can be described with reference to FIG. 1. FIG. 1 illustrates a path of light generated in a light emitting diode from which a sapphire substrate is removed. FIG. 1 (a) shows only a part of light generated by total reflection generated from the surface of the light emitting diode from which the sapphire substrate is removed. Figure 1 (b) is a schematic diagram showing a phenomenon that the light extraction efficiency of the light emitting diode is increased through the irregularities formed on the surface after removing the sapphire substrate.

Meanwhile, some researchers have fabricated a light emitting diode from which a sapphire substrate is removed by forming irregularities on the surface of gallium nitride by wet etching after n electrode formation. When the light emitting diode is manufactured in this manner, it has a structure as shown in FIG.

At this time, in the wet etching process for forming irregularities on the gallium nitride surface, a strong base such as potassium hydroxide is mainly used, and since most metals have corrosiveness to the strong base solution, there is a problem that the already formed n electrode is corroded. Generally, a metal structure such as Ti / Al is used for n-ohmic contact of a gallium nitride thin film, but since Al is corroded in a strong base solution, when Ti / Al is used as an n-omic metal and the unevenness forming process proceeds, the metal is corroded. It will disappear. Therefore, when manufacturing the light emitting device according to the prior art, there is a problem that only a limited metal such as Ti / Au should be used. In addition, even if the irregularities are formed on the gallium nitride surface by dry etching after the formation of the n electrode, the etching and / or change of the surface state of the n electrode in the plasma atmosphere occurs. Therefore, in the conventional manufacturing process, it is not possible to manufacture a light emitting diode in which sapphire substrate is removed by forming irregularities on the surface.

In order to solve this problem, the inventors of the present invention, instead of depositing a metal on the light emitting diode portion and etching the light emitting surface of the light emitting diode portion to form irregularities, the prior art method is performed in reverse order. If the metal is deposited on the semiconductor layer, for example, the n-type layer or the p-type layer, which is exposed through the etching of the uneven patterned light emitting surface, the formation of the uneven surface of the light emitting surface first may be prevented. Rather, it was found that the light extraction efficiency of the light emitting diode device can be increased due to the uneven pattern formed on the light emitting surface.

Accordingly, an object of the present invention is to provide a light emitting diode device and a method of manufacturing the light extraction efficiency is increased through the above-described process.

The present invention (a) a light emitting diode unit is formed with an uneven pattern on the light emitting surface; And (b) an ohmic contact metal layer positioned in a recess part formed by etching a portion of the light emitting surface of the uneven patterned light emitting diode portion, and a method of manufacturing the same.

In addition, the present invention comprises the steps of (a) etching the one surface of the light emitting diode portion to form an uneven pattern; (b) etching a portion of one surface of the light emitting diode having the uneven pattern to expose the semiconductor layer; And (c) depositing an ohmic contact metal on the exposed semiconductor layer.

EMBODIMENT OF THE INVENTION Hereinafter, this invention is demonstrated in detail.

The present invention is to improve the light extraction efficiency generated from the light emitting diode portion and to suppress the corrosion of the metal deposited on the light emitting surface by the etching process, to deposit a metal on the light emitting surface of the conventional light emitting diode portion and then etching Instead of forming the unevenness of the light emitting surface through, by forming the unevenness on the light emitting surface of the light emitting diode portion is characterized in that the etching and metal deposition.

Effects resulting from the difference in the process sequence and the structure of the light emitting diode device to be manufactured is distinguished as follows.

That is, when the ohmic contact metal is deposited on the light emitting surface of the light emitting diode portion as in the related art, the unevenness of the light emitting surface is formed by etching, regardless of the type of etching performed as described above, the corrosion or etching of the metal material. This results in deterioration of the characteristics of the final light emitting diode device, which requires a limited use of metal materials. On the contrary, in the present invention, the unevenness is first formed on the light emitting surface of the light emitting diode part, and then etching and metal deposition are sequentially performed so that corrosion or etching of the metal material does not occur. Therefore, various metal materials such as Ni, Au, Ag, Pt, Cr, Cu, and Rh, as well as metals such as Ti and Al, which are used as n-ohmic contact metals in general gallium nitride-based light emitting diodes, can be used.

In addition, the conventional light emitting diode device has a structure as shown in FIG. 2 in which an ohmic contact metal layer is formed on the light emitting surface of the light emitting diode part, and irregularities are formed on both sides of the ohmic contact metal layer by etching. On the other hand, the light emitting diode device of the present invention has a structure as shown in FIG. 3 as opposed to the light emitting diode device structure of FIG. Apart from this structural difference, the light extraction efficiency reduced by total reflection can be increased due to the uneven patterning formed on the light emitting surface of the light emitting diode portion.

One of the components constituting the light emitting diode device of the present invention is a light emitting diode portion in which an uneven pattern is formed on the light emitting surface by an etching process, wherein the light emitting diode portion is formed using a conventional group III-V compound known in the art. The n type layer 5, the active layer (light emitting layer), and the p type layer 7 are laminated | stacked sequentially. Non-limiting examples of the group III-V compounds include GaAs, GaP, GaN, InP, InAs, InSb, InGaN, InAlGaN, AlGaN or mixtures thereof. In this case, the p-type layer and the n-type layer may be doped with the p-type and n-type dopant, respectively, but preferably doped.

A preferred embodiment of the light emitting diode portion is (a) an undoped layer consisting of a III-V compound and (b) a semiconductor layer are sequentially stacked, wherein the semiconductor layer comprises (i) a III-V compound and n An n-type layer comprising a type dopant; (Ii) an active layer; And (iii) a p-type layer comprising a III-V compound and a p-type dopant. In this case, the n-type dopant is an impurity that increases the concentration of electrons, which is referred to as a donor, and the p-type dopant is an impurity that increases the concentration of holes, and means an acceptor.

The p-type dopant and the n-type dopant used to form the p-type layer 7 and the n-type layer 5 may be used without limitation conventional materials known in the art, that is, materials that increase the concentration of holes and electrons. . At this time, the p-type dopant mainly uses a Group II component such as Mg, and the n-type dopant preferably uses a Group IV and / or VI component such as Si, Sn, Te, or the like. In addition, the active layer (aka light emitting layer) may be a single quantum well structure or multiple quantum well structure (MQW). The semiconductor layer may include other buffer layers in addition to the p-type layer, the active layer, and the n-type layer described above. By controlling the components of the group III-V compound can be freely produced from the long wavelength to short wavelength, it can be applied to all light emitting diodes, not limited to blue nitride-based light emitting diode having an emission peak near 460 nm. have.

In order to form an uneven pattern on one surface of the light emitting diode portion of the present invention, preferably, a light emitting surface, a conventional etching treatment method known in the art, such as wet etching and / or dry etching treatment, may be used without limitation.

The ohmic contact layer is formed on a semiconductor layer such as a p-type layer or an n-type layer to be electrically connected, wherein the light emitting diode portion grown on the sapphire substrate is not directly stacked on the sapphire substrate with the n-type layer, the active layer, and the p-type layer. In order to prevent defects in the crystal structure and stacking of high quality semiconductor layers, it is common for an undoped-free dopant-grown layer to be grown first. Therefore, in the prior art, after the undoped removal is essentially performed to form the ohmic contact metal layer, the ohmic contact metal is deposited on the exposed semiconductor layer, and then the semiconductor layer is etched again to form the unevenness. For this reason, the characteristics of the light emitting diode device may be degraded by reducing the thickness of the semiconductor layer into which electrons or holes are injected when a specific voltage is applied.

In contrast, when the portion where the unevenness is formed on the light emitting surface of the present invention is an undoped layer serving as a buffer instead of the semiconductor layer, the consumption of the semiconductor layer (n-type layer and p-type layer) etched to form the unevenness Does not occur, which does not cause deterioration of characteristics of the light emitting diode device. At this time, the shape of the concave-convex may be any shape that can appear through the etching process, for example, a triangular pyramid, a cone or a hexagonal pyramid form. In addition, the unevenness formed on the light emitting surface of the light emitting diode part may have a height of the unevenness compared to the width of the unevenness in order to reduce total reflection of light generated from the light emitting diode part, but is not limited thereto. no.

Another component of the light emitting diode device of the present invention is an ohmic contact metal layer, and an ohmic contact metal is deposited on a semiconductor layer (n-type layer or p-type layer) exposed by re-etching the light emitting surface of the uneven patterned light emitting diode portion. do. The ohmic contact metal layer may be an n-ohmic contact metal layer or a p-omic contact metal layer according to a manufacturing method of a light emitting diode device, for example, a low / medium output, a high output, a laser lift-off method, or the like. As the ohmic contact metal, conventional metals known in the art, such as Ti, Al, Ni, Au, Ag, Pt, Cr, Cu, Rh or a mixed form thereof (alloy) and the like can be used. The shape and thickness of the ohmic contact metal is not particularly limited.

The ohmic contact metal is positioned in a recess formed by the etching process of the uneven patterned light emitting surface, and the recess may be appropriately adjusted according to a pattern design to be applied. In addition, the depth of the concave portion is not particularly limited, but preferably ranges from the undoped layer to the semiconductor layer of the light emitting diode portion. The ohmic contact metal may be manufactured using a metal lift-off pattern as an etching mask to facilitate the ease and simplicity of etching and metal deposition.

As a substrate on which the light emitting diode portion of the present invention is mounted, a conventional submount 10 known in the art may be used, and the material of the substrate may be composed of CuW, Si, AlN ceramic, Al ₂ O ₃ ceramic, or the like. . The size of the substrate may be larger than or equal to the light emitting diode portion, or larger than or equal to the sapphire substrate when the light emitting diode portion is grown on the sapphire substrate.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. Other objects, features, and operational advantages, including the object, operation, and effect of the present invention will become more apparent from the description of the preferred embodiment.

3 illustrates a cross-sectional structure of a light emitting diode according to an embodiment of the present invention. The p-omic contact metal layers of the light emitting diode portion exist on one plane of the submount, which is the substrate, bonded to each other. The p-type layer, the active layer (light emitting layer), and the n-type layer of the light emitting diode portion formed in a sequential stack structure are formed on the p-ohmic contact metal layer. An n-ohmic contact metal layer is located on a recess formed in a portion of the n-type layer, that is, the semiconductor layer is exposed by etching.

In the light emitting diode device configured as described above, when a specific voltage is applied by an external power source, a cathode is connected through an n-omic contact metal or an n-type layer, and an anode is connected through a submount, p-omic contact metal or a p-type layer. Connected and the current is injected. As a result, in the active layer, electrons and holes recombine with each other to emit light having an energy corresponding to a band gap or energy level difference of the active layer.

The light emitting diode device of the present invention can be manufactured as follows.

1) Unevenness forming step (see FIGS. 4A, 5A, 5B)

Unevenness is formed on one surface of the light emitting diode portion, preferably on the light emitting surface of the light emitting diode portion by using a dry or wet etching method. As such, when the unevenness is formed on the light emitting diode emitting surface, the total internal reflection of the light is reduced, and the amount of light emitted to the outside of the light emitting diode is increased.

The dry etching method is not particularly limited, but may be performed using ICP equipment known in the art. In addition, the wet etching method is not particularly limited, but, for example, an alkali solution (eg, NaOH, KOH, etc.) and a mercury lamp known in the art are used as the etching solution and the illumination source, respectively, so that the following reactions occur repeatedly. Unevenness may be formed on the light emitting surface of the diode unit.

(i) absorbs UV to form electron-hole pairs

(Ⅱ) Ga ₂ O ₃ formed on the GaN ^{surface: 2GaN + 3OH - + 6p +} → Ga 2 O 3 + N 2 + 3H +

(Ⅲ) Ga ₂ O ₃ etching in KOH _{solution: Ga 2 O 3 + 3H 2} O → 2Ga 3 + + 6OH -

→ overall reaction: 2GaN → 2Ga ^{3 +} + 1 / 2N ₂

5A and 5B are SEM images showing the light emitting surface of the light emitting diode part in which the uneven pattern is formed by performing the dry etching method and the wet etching method, respectively, and it can be seen that the uneven patterns are uniformly and densely formed.

2) etching step (see FIGS. 4b, 5c and 5d)

A portion of one surface of the light emitting diode on which the uneven pattern is formed is etched to expose a semiconductor layer such as an n-type layer or a p-type layer. In this case, the etching treatment may be performed according to a conventional method known in the art, and may use the dry etching and / or wet etching described above.

5C and 5D are SEM photographs showing the surface of the n-type layer exposed by performing the dry etching method and the wet etching method, respectively, and it can be seen that both surfaces are flat and clean.

3) forming the ohmic contact metal layer (see FIG. 4C)

After the ohmic contact metal is formed on the concave portion of the light emitting diode portion formed by the etching process, that is, the exposed semiconductor layer by vacuum deposition, heat treatment is performed to complete the ohmic contact. In this case, as described above, the metal lift-off pattern may be used as an etching mask to enable etching and metal deposition at once. For example, a metal lift-off pattern for forming an electrode may be formed and an etching process may be performed using the metal lift-off pattern, and then loaded into a vacuum deposition apparatus to form an electrode.

Subsequently, the light emitting diode part in which the ohmic contact metal layer is formed may manufacture the light emitting diode device according to a conventional method known in the art.

The diode device of the present invention can be applied regardless of the manufacturing method, the output method, and the light emitting range as long as it has the above-described structure, but a laser lift-off (LLO) type light emitting diode device is preferable.

According to the present invention, a light emitting diode device including a light emitting diode part having an uneven pattern formed on a light emitting surface and an ohmic contact metal layer positioned in a recess part formed by etching a portion of the uneven patterned light emitting surface may include: Except for forming an uneven pattern on the light emitting surface of the diode portion, and then depositing an ohmic contact metal on the exposed semiconductor layer by etching a portion of the uneven patterned light emitting surface, it can be prepared according to methods known in the art. have. As an embodiment thereof, a case in which the laser lift-off method is used will be described in detail. The method of manufacturing the light emitting diode device may include the following steps.

(1) Growth step of light emitting diode part on sapphire substrate

An undoped layer, an n-type layer, a light emitting layer on a sapphire substrate using a method such as metal organic chemical vapor deposition (MOCVD), liquid epitaxel (LPE), molecular beam epitaxial method (MBE), etc. Active layer), and then p-type layer is grown in order to form a light emitting diode portion.

(2) p-type ohmic contact forming step

Initially cleaning a wafer on which a light emitting diode structure (eg, gallium nitride) was grown on a sapphire substrate, and then forming a p-type ohmic contact metal by vacuum deposition on the upper p-type surface (eg, p-type GaN) of the wafer. Post-heat treatment is performed to complete the p-type ohmic contact.

(3) Polishing the Sapphire Substrate Surface

In general, the crystal structure of a light emitting diode is grown on a sapphire substrate having a thickness of about 430 microns. To form a mirror surface that allows laser light to easily penetrate the sapphire substrate, the sapphire substrate is thinned to about 80-100 microns through a lapping / polishing process, if necessary.

(4) bonding step with the second substrate (submount)

If necessary, for example, in the case of a high output light emitting diode, a submount substrate can be used to improve heat dissipation efficiency. That is, the polished sapphire substrate is turned over to the submount substrate so that the polished sapphire substrate is raised upward, and the p-ohmic contact metal layer face is bonded to the submount substrate. In this case, when the conductive pad portion is present on the submount substrate, the p-ohmic contact metal layer may be bonded to the conductive pad portion.

(5) unit chip forming step

If necessary, the submount substrate and the LED crystal structure may be cut into unit light emitting diode chips.

(6) lead frame bonding step

The unit chip is attached to the lead frame. In this case, the sub-mount substrate bonding step and / or the unit chip forming step may be omitted, and the p-omic contact metal layer surface of the light emitting diode may be bonded to the lead frame.

(7) laser irradiation step

In order to remove the sapphire substrate, a laser such as an excimer is irradiated. At this time, it is preferable that the wavelength of a laser beam is 365 nm or less. For example, laser light transmitted through the sapphire substrate is absorbed by gallium nitride to decompose gallium nitride in the interface region between sapphire and gallium nitride to generate metal gallium and nitrogen gas, thereby separating the sapphire substrate from the light emitting diode crystal structure.

(8) irregularities forming step according to the present invention

As described above, an uneven pattern is formed on the light emitting surface of the light emitting diode portion from which the sapphire substrate is removed.

(9) etching step

A portion of the light emitting surface on which the uneven pattern is formed is etched to expose the n-type layer.

(10) n-type ohmic contact metal forming step

An n-type ohmic contact metal is deposited on the exposed n-type surface (eg, n-type GaN).

(11) wire bonding step

Gold wire bonding is performed on the n-type surface and / or p-type surface.

(12) molding material processing step

Manufacturing of a light emitting diode is completed by covering a molding material such as epoxy or a molding material in which phosphors are mixed. At this time, the step of separating into unit chips can be carried out by changing the order as appropriate in order to facilitate the manufacturing process and simplify the process.

Embodiments of the above-described method of manufacturing a light emitting diode device are merely examples of preferred manufacturing examples, and the present invention is not limited thereto.

The light emitting diode device of the present invention includes conventional light emitting diode devices known in the art, such as blue nitride based light emitting diode devices, as well as light emitting diode devices of all other wavelengths.

In addition, the present invention provides a light emitting device having a light emitting diode device manufactured according to the above structure or the method as described above. The light emitting device includes all light emitting devices including light emitting diode elements. Examples of the light emitting device include a lighting device, a display unit, a germicidal lamp, and a display unit.

Example 1

After the substrate on which the gallium nitride-based light emitting diode portion was grown was initially cleaned, an ohmic contact metal was formed on the p-GaN surface. The sapphire substrate was wrapped to a thickness of 100 μm and then polished to remove the sapphire substrate. The wafer thus prepared was made into a unit chip having a size of 1 mm x 1 mm through scribing and breaking processes, and then the p-omic contact metal surface of the unit chip was bonded to the submount substrate. Thereafter, the sapphire substrate surface of the unit chip was irradiated with light of 248 nm wavelength at an intensity of 600 mJ / cm ² using a KrF laser to remove the sapphire substrate. After removing the metal gallium generated by removing the sapphire substrate with hydrochloric acid, ICP equipment was used to form irregularities on the surface of the gallium nitride, which is a light emitting diode part. BCl ₃ , Cl ₂ , Ar were used in a mixture, where ICP power was 250 W and RIE power was 50 W. By etching under the same conditions as described above, as shown in FIG. Subsequently, after forming a metal lift-off pattern for forming an n-electrode, it was etched to reveal an n-type gallium nitride using this as an etching mask (see FIG. 5 (c)). This sample was then loaded into a vacuum deposition equipment to form an n metal electrode, after which the metal lift-off pattern was removed with an organic solvent. The light emitting diode device was manufactured by separating the submount substrate bonded to the light emitting diode unit into one unit chip through a dicing process and attaching the same to a lead frame, followed by Au wire bonding.

The brightness of the light emitting diode device measured when a current of 300 mA was supplied to the light emitting diode device was 65.7 mW.

Example 2

A light emitting diode device was manufactured in the same manner as in Example 1, except that the unevenness was formed by wet etching instead of dry etching on the gallium nitride surface exposed by the sapphire substrate removal. At this time, a potassium hydroxide (KOH) aqueous solution was used as the wet etching solution, and a 1000 W mercury lamp was used as the illumination source. Thereafter, ICP equipment was used for the dry etching process. BCl ₃ , Cl ₂ and Ar were used in a mixture. The ICP power was 450 W and the RIE power was 50 W. As described above, the surface of the n ⁺ -GaN layer, which is exposed by performing a dry etching process on the gallium nitride surface having the uneven surface and the gallium nitride surface having the uneven surface formed by the wet etching method, is as shown in FIGS. 5B and 5D, respectively.

The brightness of the light emitting diode device measured when a current of 300 mA was applied to the light emitting diode device was 67.2 mW.

Comparative Example 1

A light emitting diode device was manufactured in the same manner as in Example 1, except that no irregularities were formed on the gallium nitride surface exposed by the sapphire substrate, and the brightness of the light emitting diode device was reduced when a current of 300 mA was applied. 43.9 mW.

Comparative Example 2

A light emitting diode device having the structure as shown in FIG. 2 by performing the same method as in Example 2, except that the irregularities were formed on the GaN surface by wet etching after n-electrode formation instead of the n-electrode after etching. Was produced.

At this time, Ti / Al was used as the n-ohmic contact metal, but the metal was peeled off from the potassium hydroxide solution used for forming the unevenness, and thus wire bonding was not possible on the electrode. This shows that it is impossible to manufacture a light emitting diode device by the manufacturing method as in Comparative Example 2 according to the prior art.

According to the present invention, by forming an uneven pattern on the light emitting surface of the light emitting diode part and then performing an etching process and forming an electrode, corrosion protection of the electrode material by the etching process and increase in light extraction efficiency of the manufactured light emitting diode device can be provided. Can be.

Claims (12)

delete delete delete delete delete delete delete delete delete (a) etching one surface of the light emitting diode part to form an uneven pattern; (b) etching a portion of one surface of the light emitting diode on which the uneven pattern is formed to expose an n-type or p-type semiconductor layer; And (c) depositing an ohmic contact metal on the exposed n-type or p-type semiconductor layer; Method of manufacturing a light emitting diode device comprising a. The method of claim 10, wherein the manufacturing method (a) growing an undoped layer, an n-type layer, an active layer, and a p-type layer on the first substrate; (b) depositing a p-ohmic contact metal on the p-type layer of the light emitting diode portion grown on the first substrate; (c) bonding the p-ohmic contact metal layer surface of the light emitting diode portion to the second substrate; (d) irradiating a laser to remove the first substrate; And (e) forming a concave-convex pattern by etching a portion of the light emitting surface of the light emitting diode part exposed while the first substrate is removed; (f) etching a portion of the light emitting surface on which the uneven pattern is formed to expose an n-type layer; And (g) depositing an n-ohmic contact metal on the exposed n-type layer; Method of manufacturing a light emitting diode device comprising a. The method of claim 10 or 11, wherein the etching process is by dry etching, wet etching, or dry and wet etching.

Images