KR101417051B1

KR101417051B1 - A light emitting diode and a method of fabricating the same

Info

Publication number: KR101417051B1
Application number: KR1020080005103A
Authority: KR
Inventors: 문용태
Original assignee: 엘지이노텍 주식회사
Priority date: 2008-01-16
Filing date: 2008-01-16
Publication date: 2014-07-08
Also published as: KR20090079123A

Abstract

A light emitting diode and a manufacturing method thereof are disclosed. A method of manufacturing the light emitting diode includes forming a first conductive semiconductor layer on a substrate, forming an active layer on the first conductive semiconductor layer, forming a second conductive semiconductor layer on the active layer, And forming protrusions in the grooves formed by partially removing the plurality of dislocation crystal defect portions on the second conductivity type semiconductor layer to realize protrusions.

Light emitting diode, protrusion, internal quantum efficiency, light extraction efficiency

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting diode (LED)

The present invention relates to a method of manufacturing a light emitting diode.

Gallium nitride based light emitting diodes (LEDs) are attracting attention in the field of optical devices due to their high thermal stability and wide band gap (energy band gap). They are gallium nitride series light emitting diodes, Various color LEDs such as UV (Ultra Violet) have been developed and commercialized.

In particular, in the case of a high-output light emitting diode such as a high-efficiency white light emitting diode, efficency has been reached to such an extent that it can replace other light emitting devices, and studies for further improving the luminous efficiency have been actively made.

However, in order to use a gallium nitride based light emitting diode in general illumination, a high output must be exhibited, so that the chip size of the light emitting device is increased and the current value to be injected is increased. Therefore, in order to replace other light emitting devices with such high output light emitting diodes, it is necessary to firstly achieve high reliability for the devices, that is, the light emitting diodes can be stably operated for a long time.

However, current gallium nitride based light emitting diodes inherently have various crystal defects due to their nature of being grown on different substrates, which results in a significant reduction in the reliability of the high output light emitting diode.

Therefore, it is required to develop a technique for effectively reducing a defect in threading dislocation which is a typical crystal defect of a gallium nitride epitaxial layer grown on a heterogeneous substrate, which has a critical effect on the reliability of a high-output light emitting diode.

An object of the present invention is to provide a light emitting diode capable of reducing crystal defects and a method of manufacturing the same.

According to an aspect of the present invention, there is provided a method of fabricating a light emitting diode, including: forming a first conductive semiconductor layer on a substrate; Forming an active layer on the first conductive semiconductor layer; Forming a second conductive semiconductor layer on the active layer; And forming protrusions in the grooves formed by partially removing the plurality of dislocation crystal defect portions on the second conductive type semiconductor layer to form protrusions.

The step of forming the protrusions may include a step of thermochemical etching the second conductivity type semiconductor layer to form the grooves.

The step of forming the protrusions may include forming a mask layer on the second conductive semiconductor layer on which the grooves are formed; And forming the projecting shape by growing the second conductive type semiconductor layer forming material having the grooves on the groove formed with the mask layer.

In the step of forming the protruding shape, the constituent material may start to grow on the side of the groove and grow in the vertical and horizontal directions to form the protruding shape.

In addition, a void may be formed in the upper portion of the protruding lower groove according to the formation of the protruding shape.

The protruding part may be formed in the same chamber as the second conductive type semiconductor layer forming step.

The forming of the second conductivity type semiconductor layer may include forming a shape protection layer on the active layer to prevent damage to the semiconductor layers underlying the active layer due to the formation of the grooves.

Here, the shape protection layer may include aluminum.

According to another aspect of the present invention, there is provided a light emitting diode including: a first conductive semiconductor layer disposed on a substrate; An active layer disposed on the first conductive semiconductor layer; A second conductive semiconductor layer located on the active layer; And a protrusion including a plurality of protruding shapes formed respectively on upper portions of the grooves formed by partially removing a plurality of potential crystal defect portions on the second conductive type semiconductor layer.

Here, the protruding portion may include a lower portion of the protruding shape, and a mask layer located on the upper portion of the groove.

In addition, the projecting portion may include a void at a lower portion of the protruding shape and at an upper portion of the mask layer in the groove.

Accordingly, the light emitting diode light emitting efficiency and device reliability can be improved.

According to the present invention, the luminous efficiency and reliability of the light emitting diode device can be improved.

Also, according to the present invention, as the light emission efficiency increases according to the protrusion shape formed on the upper portion of the light emitting diode and the crystal defects of the epi layer decrease, the reliability of the light emitting device can be improved.

In addition, according to the present invention, a crystal defect can be removed by a simple process in an epilayer growth chamber, and a crystal defect can be reduced while having excellent price competitiveness and reliability can be improved.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided by way of example so that those skilled in the art can fully understand the spirit of the present invention. Therefore, the present invention is not limited to the embodiments described below, but may be embodied in other forms. In the drawings, the width, length, thickness, etc. of components may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

1 is a cross-sectional view illustrating a light emitting diode according to an embodiment of the present invention.

Referring to FIG. 1, a light emitting diode 100 according to an embodiment of the present invention includes a substrate 1, a first conductive semiconductor layer 3, an active layer 5, a second conductive semiconductor layer 7, 8 , 9 and a protrusion (11).

The substrate 1 may be made of an insulating material such as silicon carbide (SiC), zinc oxide (ZnO), gallium arsenide (GaAs), gallium nitride (GaN), silicon (Si), lithium aluminum oxide ₂ ) or lithium gallium oxide (LiGaO ₂ ) can be used.

Although not shown, a buffer layer (not shown) may be disposed on the substrate 1 to reduce the lattice mismatch between the substrate 1 and the first conductivity type semiconductor layer 3 to a predetermined thickness. Such a buffer layer can be made of AlN, InGaN, GaN, AlGaN or the like.

The first conductivity type semiconductor layer 3 may be formed by doping an N-type impurity such as Si, Ge, Se, S, or Te.

The active layer 5 can be formed of a quantum well (QW) structure including InGaN, AlGaN, or GaN, or a multi quantum well (MQW) structure.

The second conductivity type semiconductor layers 7, 8 and 9 may include three different second conductivity type semiconductor layers, that is, a first forming layer 7, a second forming layer 8 and a third forming layer 9 have.

The second conductivity type semiconductor layers 7, 8, and 9 may be formed by doping a P-type impurity. As the P-type impurity, Be, St, Ba, Zn, or Mg may be used.

The first forming layer 7 formed first among the first conductivity type semiconductor layers may be formed of Al _x In _y Ga _(1-XY) N (where _0? _X, _Y _{? 1} and 0? X + Y? 1) And the second conductivity type semiconductor layer.

In particular, the second generation layer 8, which is the second one of the second conductivity type semiconductor layers, is a gallium nitride semiconductor thin film layer containing aluminum (Al _x In _y Ga _(1-XY) 1, 0? Y? 1, and 0 <X + Y? 1).

Then, a gallium nitride semiconductor thin film layer containing no aluminum (Al), that is, an In _Y Ga _(1-Y) N ( _{0? Y? 1} ) material film is formed on the second generation layer 8 The third generation layer 9 is formed.

At least a part of the surface of the second conductivity type semiconductor layer (7, 8, 9) is provided with a protrusion (11). The protrusions 11 are formed in the upper part of the grooves formed by etching a plurality of dislocation crystal defect portions located at least on a surface of the surface of the tertiary layer 9 as a gallium nitride second conductive type semiconductor thin film layer not containing aluminum, And includes a plurality of protruding features formed in the form of a protrusion. Each projecting shape of the projecting portion 11 may include a void at an inner bottom surface of the groove formed at a lower portion thereof. In addition, for example, a magnesium nitride (MgN) mask layer may be located on the inner bottom surface of the groove. The structure of the protrusion 11 and the method of forming the protrusion 11 will be described later in more detail.

The projections 11 including a plurality of island-like projections formed on the surface of the second conductivity type semiconductor layer 11 are formed on the grooves formed by the etching of the dislocation crystal defects so that the shape of the projections can be, for example, Pyramid shape and may be irregular in size and arrangement.

Therefore, the light emitted from the active layer 5 and radiated into the semiconductor layers is reflected or diffused by the projecting shape of the protrusion 11 formed on the second conductivity type semiconductor layer 9, And can be easily released into the air to increase the luminous efficiency of the light emitting device.

The light emitting diode 100 partially etches part of the second conductivity type semiconductor layers 7, 8 and 9, the active layer 5 and the first conductivity type semiconductor layer 3, (3) is exposed to the outside. In this case, the exposed portion of the first conductivity type semiconductor layer 3 is also formed into a protruding shape by directly transferring the projected shape of the protrusion 11 formed on the second conductivity type semiconductor layer 9 by etching .

The electrode pads 13 and 14 are formed on the exposed first conductivity type semiconductor layer 3, the second conductivity type semiconductor layer 9, and the protrusion 11, respectively. On the other hand, though not shown in the drawing, on the second conductivity type semiconductor layer 9 and the protrusions 11, ohmic contact for reducing the contact resistance between the semiconductor and the metal and / or light generated in the active layer 5 can be efficiently For example, a transparent electrode (not shown) may be formed to have a small thickness in order to radiate the light to the outside.

2 to 6 are views for explaining a method of manufacturing a light emitting diode according to an embodiment of the present invention.

Referring to FIG. 2, a first conductive semiconductor layer 1 of Al _x In _y Ga _(1-xy) N (where _0? _X, _Y _{? 1} and 0? X + (3) is formed.

On the other hand, before forming the first conductivity type semiconductor layer 3, a buffer layer (not shown) which is an undoped nitride semiconductor layer may be formed on the substrate 1. In this case, the buffer layer (not shown) may be formed of a material film of Al _x In _y Ga _(1-XY) N (where _0? _X, _Y _{? 1} and 0? X + Y? 1) , GaN, AlGaN, or the like is used.

The semiconductor layers described above and described below may be formed using metalorganic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), molecular beam epitaxy (MBE) Can be formed in the same chamber.

The active layer 5 is formed on the first conductive semiconductor layer 3. The active layer 5 may be formed to have a single quantum well structure or a multiple quantum well structure. The active layer 5 may be formed of an InGaN, AlGaN, or GaN material film, and the composition ratio of each metal element is determined according to the required emission wavelength.

Thereafter, the second conductivity type semiconductor first generation layer 7 is formed on the active layer 5, and may be formed as a single layer or multiple layers. When the first conductivity type semiconductor layer 3 is n-type, the second conductivity type semiconductor primary layer 7 may be formed by doping a p-type impurity. The second conductivity type semiconductor primary layer 7 can be grown at a high temperature and at a high temperature so that crystal defects of the thin film can be minimized, thereby enhancing the internal quantum efficiency of the light emitting device.

Next, the second generation layer 8, which is the second one of the second conductivity type semiconductor layers, is formed of a gallium nitride semiconductor material layer containing aluminum (Al). The gallium nitride semiconductor material layer containing aluminum is excellent in thermochemical stability and thus can serve as a shape protection layer for protecting the semiconductor layers from a subsequent thermochemical etching process.

Then, a tertiary layer 9, which is the third of the second conductive type semiconductor layers, is formed of a gallium nitride semiconductor thin film layer not containing aluminum (Al) on the secondary layer 8, which is a shape protection layer.

Referring to FIG. 3, dislocation defects D as shown in FIG. 3 are formed in the first conductivity type semiconductor layer 3, the active layer 5, and the second conductivity type semiconductor layers 7, 8, .

Next, thermochemical etching is performed in the thin film growth chamber in which the second conductivity type semiconductor layers 7, 8, and 9 are formed. In this case, the etching temperature of the growth chamber may be, for example, 800 DEG C or higher, and hydrogen, nitrogen, ammonia, or a mixed gas thereof may be used as the atmosphere gas. Further, it is preferable that the etching process is performed in a state where the atmospheric gas is introduced into the growth chamber through the thin film growth furnace at a constant rate.

FIG. 4 is a cross-sectional view of the second conductive type semiconductor layered structure according to the first embodiment of the present invention. FIG. 4 is a cross- Fig.

As shown in FIG. 4, when thermochemical etching is performed, etching is preferentially performed around the dislocation crystal defects existing on the surface of the second conductivity type semiconductor tertiary layer 9 that does not contain aluminum, A plurality of grooves H are formed on the surface of the second conductivity type semiconductor tertiary layer 9 containing no aluminum. The dislocation crystal defects are energetically unstable compared to the thin film surface without dislocation defects, so that the surface atoms are preferentially dropped in the atmospheric gas at a high temperature and in the reactive atmosphere, and etching proceeds, and holes are formed in the dislocation crystal defects .

Further, this thermochemical etching process does not proceed in the second conductivity type semiconductor secondary layer 8, which is a gallium nitride series semiconductor layer containing aluminum. This is because the atomic chemical bonding force between aluminum and nitrogen is much stronger than that between gallium and nitrogen, and the atomic chemical bonding force between indium and nitrogen.

Next, as shown in FIG. 5, the second conductive type semiconductor layer 8, which is a gallium nitride-based semiconductor layer including aluminum locally formed therein, is exposed, and a gallium nitride A mask layer 10 such as magnesium nitride (MgN), for example, is formed on the surface of the second conductivity type semiconductor tertiary layer 9 which is a semiconductor layer. The mask layer 10 may be formed by, for example, implanting a magnesium atom source gas and a nitrogen atom source gas into the growth chamber for a predetermined period of time. At this time, the thickness of the magnesium nitride mask layer 10 may be, for example, 1 nm or less.

5, the mask layer 10 of magnesium nitride is formed on the uppermost exposed surface of the semiconductor layer, and on the side of the groove H, the formation of the mask is relatively limited due to geometrical reasons do.

Thereafter, the gallium nitride-based second conductivity type semiconductor layer is again deposited to form another protrusion 11 which is the second conductivity type semiconductor layer. Thus, the gallium nitride based second conductivity type semiconductor layer starts to grow on the side inside the groove H of the dislocation defect portion where the magnesium nitride mask is not deposited. The gallium nitride-based second conductivity type semiconductor layer, which has begun to grow on the side of the inside of the groove H, grows in the longitudinal direction and also grows in the lateral direction, and as shown in FIG. 6, Thereby forming a plurality of protruding island-shaped protruding shapes. In addition, a small void space, that is, a void V may be formed at the lower end of the protruding shape protruding from the center of the groove H, that is, the bottom surface of the groove H. The size, shape and cavity (V) of the island can be controlled by controlling the growth condition of the thin film.

Thus, dislocation crystal defects penetrating from the lower layer to the upper layer of the semiconductor thin film can be effectively blocked by the magnesium nitride mask layer 10 formed at the bottom of the groove H. [

In addition, it is possible to effectively block dislocation crystal defects which are detrimental to electrical reliability such as lifetime and leakage current of a gallium nitride semiconductor light emitting device, and thus electric and optical reliability of a device in a large-area high output light emitting device can be remarkably improved. Thereafter, the protrusions 11, the second conductivity type semiconductor layers 9, 8, and 7, and the active layer 5 are sequentially patterned to expose a region of the first conductivity type semiconductor layer 3. Such patterning may be performed using a photolithographic and etching process. In this case, the exposed portion of the first conductivity type semiconductor layer 3 may also be formed in a protruding shape by directly transferring the protruding shape of the protruding portion 11 by an etching process.

Thereafter, an electrode pad 13 is formed on the exposed first conductive type semiconductor layer 3, and an electrode pad 14 is formed on the second conductive type semiconductor layer 9 and the projected portion 11 . The region of the upper surface of the second conductivity type semiconductor layer 9 where the electrode pad 14 is to be formed may be formed by planarizing at least a part of the projected portion 11 and then forming the second conductivity type semiconductor layer 9, The electrode pad 14 may be formed on the electrode pad 14. At least a part of the exposed portion of the first conductivity type semiconductor layer 3 to be formed with the electrode pad 13 may be planarized and then the electrode pad 14 may be formed on the planarized region.

Although not shown in the drawing, a transparent electrode (not shown) may be formed on the second conductivity type semiconductor layer 9 and the protrusion 11 as described above. The projecting shape of the protrusion 11 may be transferred to the transparent electrode (not shown) so that the transparent electrode (not shown) has a protruding shape.

The transparent electrode (not shown) is formed on the second conductivity type semiconductor layer 9 and the protrusion 11 before the electrode pad 14 is formed after exposing a region of the first conductivity type semiconductor layer 3 However, before the first conductive semiconductor layer 3 is exposed, an electrode layer may be formed using an e-beam evaporation technique, and then patterned using a photolithography and etching process to form an electrode layer It is possible.

According to the method for fabricating a light emitting diode according to an embodiment of the present invention, a gallium nitride based thin film is grown at a high temperature at a high temperature, so that the crystallinity of the light emitting device is excellent, and the internal light emitting efficiency is high and the reliability of the light emitting device can be increased. Further, since a large number of high-quality protrusions are formed on the surface of the thin film, the light extraction efficiency is high and the electrical resistance is low.

7 is a cross-sectional view illustrating a light emitting diode according to another embodiment of the present invention. In the description of the light emitting diode according to another embodiment of the present invention shown in FIG. 7, the description of the similar or identical parts to those of the light emitting diode according to the embodiment of the present invention described above will be omitted.

7, a light emitting diode according to another embodiment of the present invention includes second conductive semiconductor layers 9, 8 and 7, an active layer 5, and a first conductive semiconductor layer (3) are stacked. On the other hand, on the lower surface of the second conductivity type semiconductor layer 9, a plurality of protruding portions 11 are formed. A plurality of protrusions 11 may be irregularly arranged on the lower surface of the second conductivity type semiconductor layer 11. A reflective film 17 and a thin metal film 18 may be disposed between the conductive holder 19 and the second conductivity type semiconductor layer 9 and between the projections 11.

The first electrode 20 is laminated on the upper portion of the conductive holder 19 and the second electrode 21 and the electrode pad 22 are sequentially stacked under the exposed first conductivity type semiconductor layer 3 .

Although not shown, a layer of an ohmic contact material such as a transparent conductive oxide (TCO) may be disposed between the second conductive semiconductor layer 9 and the protrusion 11 and the reflective layer 17 have.

Accordingly, the light emitted from the active layer 5 and radiated into the semiconductor layers is reflected by the protruding shape of the protruding portion 11, and is reflected to the inside of the semiconductor layer without being totally reflected therein, .

FIG. 7 is a cross-sectional view illustrating a light emitting diode according to another embodiment of the present invention shown in FIG. Hereinafter, a method for forming a light emitting diode having the above-described structure will be briefly described with reference to FIGS. 2 to 7. FIG.

The first conductivity type semiconductor layer 3, the active layer 5, and the second conductivity type semiconductor first generation layer 7 are sequentially formed on the sacrificial substrate 1 as shown in FIG. When the first conductivity type semiconductor layer 3 is an n-type, the second conductivity type semiconductor first generation layer 7 and the second conductivity type semiconductor second and third generation layers 8 and 9 to be described later are p-type impurities And may be formed by doping. The second conductivity type semiconductor first generation layer 7 and the second conductivity type semiconductor second and third generation layers 8 and 9 to be described later are grown at a high temperature and at a high temperature so that crystal defects of the thin film can be minimized, The quantum efficiency can be improved.

Next, the second generation layer 8, which is the second one of the second conductivity type semiconductor layers, is formed of a gallium nitride semiconductor material layer containing aluminum (Al). The gallium nitride semiconductor material layer containing aluminum is excellent in thermal chemical stability, and therefore, when a groove is formed in the second conductivity type semiconductor layer forming layer 9 described later by a thermochemical etching process, damage to the semiconductor layers is prevented And can function as a shape-protecting layer.

Then, a tertiary layer 9, which is the third one of the second conductivity type semiconductor layers, is formed of a gallium nitride semiconductor thin film layer not containing aluminum (Al) on the secondary layer 8 as a shape protection layer.

Then, thermochemical etching is performed in the thin film growth chamber in which the second conductivity type semiconductor layers 7, 8, and 9 are formed. As shown in FIG. 4, according to the thermochemical etching process, A plurality of grooves H are formed on the surface of the second conductivity type semiconductor tertiary layer 9 by etching preferentially in the dislocation-defective portion of the surface of the second conductivity type semiconductor tertiary layer 9 to form the second conductivity type semiconductor 2 The surface of the tea-forming layer 8 is exposed.

5, a mask layer such as magnesium nitride (MgN) is formed on the exposed surfaces of the second conductivity type semiconductor layer 8 and the second conductivity type semiconductor layer 9, 10).

Thereafter, the gallium nitride-based second conductivity-type semiconductor layer is again deposited to form a plurality of protruding portions 11 of another second conductivity type semiconductor layer. As described above, the projecting shape of the projecting portion 11 starts to grow on the side in the groove H of the dislocation-deficient portion where the mask is not deposited, and grows in the longitudinal direction and also grows in the lateral direction, Like projecting shape protruding about the groove H as shown in Fig. In addition, a small void space, that is, a void V may be formed at the lower end of the protruding shape protruding from the center of the groove H, that is, the bottom surface of the groove H.

Then, a reflective film 17, a metal thin film 18 and a conductive holder 19 are sequentially formed. 8, the sacrificial substrate 1 is separated from the semiconductor layers, and the electrode 21 and the electrode pad 22 are sequentially formed on the lower portion of the exposed first conductive type semiconductor layer 3 .

As the sacrificial substrate 1, all kinds of substrates as described above can be used, and a substrate in which a gallium nitride (GaN) template is grown on sapphire or other substrate can be used. A metal layer (not shown) such as a nitrogenated metal may be formed on the sacrificial substrate 1 using a metal such as Ti or W before forming the first conductive semiconductor layer 3 . In addition, although not shown in the figure, on the metal layer (not shown) or on the sacrificial substrate 1, there are formed a first conductive semiconductor layer 3, A buffer layer (not shown) of Un-doped GaN can be further formed.

The formation of the conductive holder 19 is for supporting the light emitting diode semiconductor layers after the removal of the sacrificial substrate (not shown) in a subsequent process, and for facilitating electrode formation. The conductive holder 19 may be formed by electroplating using the metal thin film 18 as a seed metal after depositing a metal thin film 18 on the reflective film 17. However, the conductive holder 19 is not limited to this method and can be formed in various ways.

Although not shown in the figure, before forming the reflective layer 17 on the second conductive semiconductor layer 9 and the protruding portion 11, an ohmic contact material (not shown) such as TCO Can be formed first.

Then, the sacrificial substrate 1, the metal layer (not shown) and the buffer layer (not shown) are removed from the bottom of the first conductivity type semiconductor layer 3 by a mechanical or chemical method such as laser lift off or wet etching, Thereby exposing the lower portion of the semiconductor layer 3.

7, a first electrode 20 is formed on the conductive holder 19, and a second electrode 21 and an electrode pad 21 are formed under the exposed first conductive semiconductor layer 3, (22) can be sequentially formed. The first electrode 20 and the electrode pad 22 are preferably made of a metal for ohmic contact.

The light emitting diode formed by this method can greatly improve the light extraction efficiency depending on the protruding shape of the protruding portion 11.

9 is a cross-sectional view illustrating a light emitting diode according to another embodiment of the present invention. In the description of the light emitting diode according to another embodiment of the present invention shown in FIG. 9, a description of portions similar or identical to those of the light emitting diode according to the embodiment of the present invention described above will be omitted.

9, a light emitting diode according to another embodiment of the present invention includes a first conductive semiconductor layer 3, an active layer 5, and a second conductive semiconductor layer 7, 8 , 9) are stacked. On the other hand, a plurality of protrusions 11 are formed on the upper surface of the second conductivity type semiconductor layer 9. A plurality of protrusions 11 may be irregularly arranged on the upper surface of the second conductivity type semiconductor layer 9. A reflective layer 17 may be disposed between the conductive holder 19 and the first conductivity type semiconductor layer 3.

The first electrode 20 is stacked on the conductive holder 19 and the second conductive type semiconductor layer 9 and the second conductive type semiconductor layer 9 are formed on the upper portion of the protrusion 11, The electrode 21 is positioned, and the electrode pad 22 is positioned on the electrode 21.

9 is a cross-sectional view illustrating a method of manufacturing a light emitting diode according to another embodiment of the present invention.

Hereinafter, a method of manufacturing a light emitting diode having the above-described structure will be described with reference to FIGS. 2 to 6 and 9. FIG.

The first conductivity type semiconductor layer 3, the active layer 5 and the second conductivity type semiconductor first layer 7 are sequentially formed on the sacrificial substrate 1 as shown in FIG. Al). The second conductivity type semiconductor layer 8 is formed of a gallium nitride-based semiconductor material layer. Then, the second conductivity type semiconductor tertiary layer 9 is formed on the second conductivity type semiconductor layer 8 with a gallium nitride semiconductor thin film layer not containing aluminum (Al).

Next, thermochemical etching is performed in the thin film growth chamber in which the second conductivity type semiconductor layers 7, 8, and 9 are formed to form a second conductivity type semiconductor tertiary layer (not shown in FIG. 3) 9, the etching proceeds preferentially in the portion of the dislocation defect (D) on the surface to form a plurality of grooves (H) on the surface of the second conductivity type semiconductor tertiary layer (9).

Thereafter, a plurality of protruding portions 11, which are the second conductivity type semiconductor layers, are formed. As described above, the projecting shape of the projecting portion 11 starts to grow on the side in the groove H of the dislocation-deficient portion where the mask is not deposited, and grows in the longitudinal direction and also grows in the lateral direction, Like projecting shape protruding about the groove H as shown in Fig. In addition, a small void space, that is, a void V may be formed at the lower end of the protruding shape protruding from the center of the groove H, that is, the bottom surface of the groove H.

As shown in FIG. 3, the second conductivity type semiconductor tertiary layer 11 is formed on the second conductivity type semiconductor secondary layer 9, so that the nitrogen-polarized-type reverse phase region in the gallium- Grow.

Thereafter, wet etching is performed as shown in FIG. 4 to selectively remove the nitrogen-polarized reverse phase region from the surface of the second conductivity type semiconductor tertiary layer 11.

In order to facilitate the removal process of the sacrificial substrate 1 before forming the first conductivity type semiconductor layer 3 on the sacrificial substrate 1, a metal such as Ti, W, The same metal layer (not shown) can be formed. In addition, although not shown in the figure, on the metal layer (not shown) or on the sacrificial substrate 1, there are formed a first conductive semiconductor layer 3, A buffer layer (not shown) of Un-doped GaN can be further formed.

As the sacrificial substrate 1, any type of substrate may be used as described above, or a substrate in which a gallium nitride (GaN) template is grown on sapphire or other substrate may be used.

10, an auxiliary substrate 16 is formed on the second conductive type semiconductor layer 9 opposite to the sacrificial substrate 1 and the protruding portion 11. As shown in FIG. The auxiliary substrate 16 may be formed by applying an adhesive to the upper surface of the second conductivity type semiconductor layer 9 and the protrusions 11 and attaching various kinds of substrates such as glass, sapphire, and silicon substrates. It is possible to prevent the semiconductor layers from being damaged during the subsequent process of removing the sacrificial substrate 1 as well as the formation of the electrodes and the reflective film by forming the auxiliary substrate 16 and thereby improving the reliability of the light, .

After the auxiliary substrate 16 is formed, the semiconductor layers may be separated from the sacrificial substrate 1 by using a laser lift off method, or a mechanical process using a vacuum chuck or the like, The metal layer (not shown) may be removed by a chemical method such as wet etching to separate the sacrificial substrate 1 and expose a lower portion of the first conductive type semiconductor layer 3. [ When a buffer layer (not shown) is formed on the sacrificial substrate 1, the metal layer (not shown) and the buffer layer (not shown) are removed to remove the sacrificial substrate 1 ) Can be separated from the semiconductor layers.

9, a reflective film 17 and a conductive holder 19 are sequentially formed on the bottom of the exposed first conductive semiconductor layer 3. Then, as shown in FIG. The reflective layer 17 may be formed after placing an ohmic contact material on the lower portion of the first conductivity type semiconductor layer 3, if necessary. The conductive holder 19 supports the light emitting diode semiconductor layers after the auxiliary substrate 16 is removed in a subsequent process, and can facilitate electrode formation.

The conductive holder 19 may be formed by applying an adhesive (not shown) such as a solder to the upper part of the reflective film 17 and then plating it or by forming a metal such as silicon (Si), silicon A carbide (SiC) substrate may be attached. The conductive holder 19 is formed by depositing a metal thin film (not shown) on the reflective film 17 and then electroplating the metal thin film (not shown) as a seed metal .

The auxiliary substrate 16 is separated from the second conductivity type semiconductor layer 9 and the protrusions 11 and the first electrode 11 is formed on the second conductivity type semiconductor layer 9 and the protrusions 11, 21 and an electrode pad 22 are sequentially formed on the lower surface of the conductive holder 19 and the second electrode 20 is formed on the entire lower surface of the conductive holder 19.

The auxiliary substrate 16 is formed by wet etching the adhesive used to adhere the auxiliary substrate 16 on the second conductivity type semiconductor layer 11 to form the second conductivity type semiconductor layer 9 And the projecting portion 11, as shown in Fig.

A region of the upper surface of the second conductive type semiconductor layer 9 where the electrode pad 19 is to be formed may be formed by planarizing at least a part of the projecting shape of the projecting portion 11, (22) may be formed.

Meanwhile, in the above-described embodiment, by forming the reflective film and the conductive holder on the second conductive type semiconductor layer 9 and the protruding portion 11 in contrary to the above-described structure, the light emitting element formed through the above- As shown in FIG.

Although the preferred embodiments of the present invention have been described, the present invention is not limited to the specific embodiments described above. It will be apparent to those skilled in the art that numerous modifications and variations can be made in the present invention without departing from the spirit or scope of the appended claims. And equivalents should also be considered to be within the scope of the present invention.

FIGS. 2 to 6 are cross-sectional views illustrating a method of manufacturing a light emitting diode according to an embodiment of the present invention.

7 and 8 are cross-sectional views illustrating a light emitting diode and a method of manufacturing the same according to another embodiment of the present invention.

9 and 10 are cross-sectional views illustrating a light emitting diode according to another embodiment of the present invention and a method of manufacturing the same.

Claims

Forming a first conductive type semiconductor layer on a substrate;

Forming an active layer on the first conductive semiconductor layer;

Forming a second conductive semiconductor layer on the active layer; And

And forming protrusions in the grooves formed by partially removing a plurality of dislocation crystal defect portions on the second conductive type semiconductor layer to realize protrusions.

The method according to claim 1,

The protrusion implementing step includes:

And thermochemical etching is performed on the second conductive semiconductor layer to form the grooves, respectively.

3. The method of claim 2,

The protrusion implementing step includes:

Forming a mask layer on the second conductive semiconductor layer on which the grooves are formed; And

And growing the second conductivity type semiconductor layer forming material having the grooves on the groove formed with the mask layer to form the protruding shape.

The method of claim 3,

Wherein the forming material starts to grow on the side surface of the groove and grows in the vertical and horizontal directions to form the protruding shape in the step of forming the protruding shape.

5. The method of claim 4,

Wherein a void is formed in an upper portion of the protruding lower groove according to formation of the protruding shape.

3. The method of claim 2,

Wherein the step of forming the protrusion is performed in the same chamber as the step of forming the second conductive type semiconductor layer.

3. The method according to claim 1 or 2,

The forming of the second conductivity type semiconductor layer may include:

And forming a shape protection layer on the active layer to prevent damage to the semiconductor layers lying below the active layer due to the groove formation.

8. The method of claim 7,

Wherein the shape protection layer comprises aluminum.

A first conductive semiconductor layer disposed on a substrate;

An active layer disposed on the first conductive semiconductor layer;

A second conductive semiconductor layer located on the active layer; And

And a protrusion including a plurality of protruding shapes formed respectively on upper portions of the grooves formed by partially removing a plurality of dislocation crystal defect portions on the second conductivity type semiconductor layer.

10. The method of claim 9,

The projection

A lower portion of the projecting shape, and a mask layer located on the upper portion of the groove.

11. The method of claim 10,

The projection

A bottom of the protruding shape, and a void at an upper portion of the mask layer in the groove.

10. The method of claim 9,

Further comprising a shape protection layer located on the active layer to prevent damage to the semiconductor layers underlying the active layer due to the formation of the groove.

13. The method of claim 12,

Wherein the shape protection layer comprises aluminum.