KR101449032B1

KR101449032B1 - flip-chip structured group 3 nitride-based semiconductor light emitting diodes and methods to fabricate them

Info

Publication number: KR101449032B1
Application number: KR1020080033987A
Authority: KR
Inventors: 송준오
Original assignee: 엘지이노텍 주식회사
Priority date: 2008-04-13
Filing date: 2008-04-13
Publication date: 2014-10-08
Also published as: KR20090108675A

Abstract

The present invention includes a thin film structure composed of first, second, and third ohmic contact current spreading layers on the upper surface of the upper nitride-based clad layer which is the light emitting surface of the group III nitride-based semiconductor light-emitting diode device A group III nitride-based semiconductor light-emitting diode element and a method of manufacturing the same.

More specifically, the present invention relates to a p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductor upper surface of a nitride based clad layer of a light emitting structure for a light- 1 ohmic contact current spreading layer, a group III nitride-based conductive thin film structure as a current spreading layer, a transparent conductive thin film structure as a second ohmic contact current spreading layer, and a reflective conductive thin film structure as a third ohmic contact current spreading layer. Prior to growing the spreading layer, the p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductors and ohmic contact current spreading The superlattice structure is interposed between the layers to facilitate current injection in the vertical direction and the overall performance of the light emitting diode device including the driving voltage and the external light emitting efficiency can be effectively improved.

A group III nitride-based conductive thin film structure, a transparent conductive thin film structure, a reflective conductive thin film structure, an ohmic contact current spreading layer, a light extracting structure, a surface irregularity

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flip-chip group III nitride-based semiconductor light-emitting diode device and a method of fabricating the same,

The present invention relates to a method for manufacturing a semiconductor light emitting device, comprising the steps of: forming a first ohmic contact film on a p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + An ohmic contact current spreading layer composed of a group III nitride-based conductive thin film structure as a diffusion layer, a transparent conductive thin film structure as a second ohmic contact current spreading layer, and a reflective conductive thin film structure as a third ohmic contact current spreading layer Prior to growth, the p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductor and the first, second, and third A superlattice structure is inserted between the thin film structures composed of the ohmic contact current spreading layer to facilitate current injection in the vertical direction and the first or second ohmic contact current spreading The surface irregularity process is introduced on the upper surface of the layer, It is possible to effectively improve the overall performance of the light emitting diode device including the light emission efficiency.

When a forward current of a certain size is applied to a light emitting diode (LED) device, the current in the active layer in the solid-state light-emitting structure is converted into light to generate light. The earliest LED element research and development forms a compound semiconductor such as indium phosphide (InP), gallium arsenide (GaAs), and gallium phosphorus (GaP) in a p-i-n junction structure. The LED emits light of a visible light range of a wavelength band longer than the wavelength of green light, but recently, a device emitting blue and ultraviolet light is also commercialized due to research and development of the group III nitride-based semiconductor material system. Device, a light source device, and an environmental application device. Further, it is possible to combine three LED device chips of red, green, and blue, or to add a phosphor to a short wavelength pumping LED device LEDs for white light source that emits white light by grafting have been developed and the application range thereof has been extended to illumination devices. In particular, LED devices using solid single crystal semiconductors have a high efficiency of converting electrical energy into light energy, have a long life span of 5 years or more on average, and are capable of significantly reducing energy consumption and maintenance costs. It is attracting attention.

Since a light-emitting diode (hereinafter referred to as a group III nitride-based semiconductor light-emitting diode) device manufactured from the group III nitride-based semiconductor material is generally grown on an insulating growth substrate (typically, sapphire) -5 group compound semiconductor light emitting diode device, two electrodes of the LED device facing each other on the opposite sides of the growth substrate can not be provided, so that the two electrodes of the LED device must be formed on the upper part of the crystal growth material. A conventional structure of such a group III nitride-based semiconductor light-emitting diode device is schematically illustrated in FIGS. 5 and 7. FIG.

5, the group III nitride-based semiconductor light-emitting diode device includes a sapphire growth substrate 10 and a lower nitride-based clad made of an n-type conductive semiconductor material sequentially grown on the growth substrate 10 Layer 20, a nitride-based active layer 30, and a top nitride-based clad layer 40 made of a p-type conductive semiconductor material. The lower nitride-based cladding layer 20 may be composed of n-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductor multilayers, Is a group III nitride-based In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductor multilayer composed of different compositions of a multi-quantum well structure . The upper nitride-based cladding layer 40 may be composed of a semiconductor multilayer of p-type In x Al y Ga 1-x-y N (0? X, 0? Y, x + y? 1) In general, the lower nitride-based cladding layer / nitride-based active layer / upper nitride-based cladding layers 20, 30, and 40 formed of the Group III nitride-based semiconductor single crystal are formed by a device such as MOCVD, MBE, HVPE, sputter, . &Lt; / RTI > In order to improve the lattice matching with the sapphire growth substrate 10 prior to the growth of the n-type In x Al y Ga 1-xy N semiconductor as the lower nitride-based cladding layer 20, The buffer layer 201 may be formed therebetween.

As described above, since the sapphire growth substrate 10 is an electrically insulating material, both electrodes of the LED device must be formed on the same top surface in the direction of growth of the monocrystal semiconductor. For this purpose, the upper nitride-based clad layer 40 and the nitride- A part of the upper surface region of the lower nitride-based clad layer 20 is exposed to the atmosphere by etching (i.e., etching) a part of the active layer 30 to form the n-type In an n-type ohmic contact interface electrode and an electrode pad 80 are formed on the upper surface of x Al y Ga 1-xy N semiconductor.

In particular, since the upper nitride-based clad layer 40 has a relatively high sheet resistance due to a low carrier concentration and a small mobility, An additional material capable of forming the ohmic contact current spreading layer < RTI ID = 0.0 > 501 < / RTI > On the other hand, U.S. Patent No. 5,563,422 discloses that a p-type In x Al y Ga 1-xy N (40) semiconductor (n-type) semiconductor layer 40, which is a top nitride-based cladding layer 40 located in an upper layer portion of a light emitting structure for a group III nitride- Before the formation of the p-type electrode 80 on the upper surface, a nickel-gold (Ni) -type electrode layer is formed to form an ohmic contact current spreading layer 501 which forms an ohmic contact interface having a low non- (Ni-O-Au).

The ohmic contact current spreading layer 501 is formed on the upper surface of the p-type In x Al y Ga 1-xy N semiconductor which is the upper nitride-based cladding layer 40 while improving the current spreading in the horizontal direction , An ohmic contact interface having a low noncontact resistance in the vertical direction can be formed and current injection can be performed effectively, thereby improving the electrical characteristics of the light emitting diode device. However, the ohmic contact current spreading layer 501 made of oxidized nickel-gold shows an average transmittance as low as 70% even after the heat treatment, and the low light transmittance is lower when the light generated from the light emitting diode device is emitted to the outside , And absorbs a large amount of light, thereby reducing the overall external luminous efficiency.

As described above, in order to obtain a high-brightness light emitting diode device having a high light transmittance of the ohmic contact current spreading layer 501, various kinds of materials including the oxidized nickel-gold (Ni-O-Au) A method has been proposed in which a transparent conductive material such as indium tin oxide (ITO) or zinc oxide (ZnO), which is known to have an average transmittance of 90% or more, is proposed instead of the ohmic contact current spreading layer 501 formed of a semi- . The above-mentioned transparent electroconductive material is a p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductor (~ 7.5 eV or more (4.7 to 6.1 eV) and p-type In x Al y Ga 1-x y N semiconductor layer directly on the upper surface of the semiconductor, and after the subsequent process including the heat treatment, the ohmic contact interface, There is a need for a new transparent conductive material or a manufacturing process which can solve the above-mentioned problems, because it forms a schottky contact interface.

A transparent conductive material such as ITO or ZnO is formed on the upper surface of the p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductor which is the upper nitride- Recently, YK Su et al. Have reported that the above-mentioned transparent electroconductive material can be used as a good ohmic contact current spreading layer 501 of p-type In x Al y A current spreading layer having an ohmic contact interface via a superlattice structure is formed prior to the direct deposition of Ga 1-xy N (0? X, 0? Y, x + y? 1) 501) formation technology.

As shown in FIG. 6, the superlattice structure includes two layers a1 and b1 of a well b1 and a barrier a1 in a multi-quantum well structure. The thickness of the barrier a1 of the multiple quantum well structure is relatively thick compared to the thickness of the well b1 while the thickness of the barrier a1 of the multiple quantum well structure is relatively thicker than that of the well b1, (a2, b2) all have a thin thickness of 5 nm or less. Due to the above-described characteristic, the multiple quantum well structure plays a role of confinement of electrons or holes as carriers into a well b1 located between the thick barrier a1, And facilitates the transport of the liquid.

Referring to FIG. 7, a light emitting diode device having an ohmic contact current spreading layer 60 using a superlattice structure proposed by YK Su et al. Will be described. The group III nitride semiconductor light emitting diode device includes a sapphire growth substrate 10 and a lower nitride-based clad layer 20 made of an n-type conductive semiconductor material formed on the upper surface of the growth substrate 10, a nitride-based active layer 30, and a upper nitride-based clad layer 40, and a superlattice structure 90. In particular, the superlattice structure 90 is grown in situ with the same growth equipment as the lower nitride-based cladding layer 20, the nitride-based active layer 30, and the upper nitride-based cladding layer 40 Growth. The lower nitride-based cladding layer 20 may be composed of n-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductor multilayers, (0? X, 0? Y, x + y? 1) semiconductor multilayers composed of Group III nitride-based In x Al y Ga 1-xy N (different compositions of a multi-quantum well structure) have. The upper nitride-based cladding layer 40 may be composed of p-type In x Al y Ga 1-x-y N (0? X, 0? Y, x + y? 1) semiconductor multilayers. Further, the superlattice structure 90 may be formed of Group III nitride-based In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductors or other boards (0? X, 0? Y, x + y? 1) semiconductor multilayers of Group III nitride type In x Al y Ga 1-xy N having a dopant.

Depending on the composition and the type of dopant constituting the superlattice structure 90, the p-type In x Al y Ga 1-xy N (0? X, 0 Y, x + y < / = 1) to increase the net effective hole concentration by lowering the dopant activation energy of the semiconductor, or by quantum tunneling conduction through band- It is known to form an ohmic contact interface through the phenomenon of mechanical tunneling transport.

In general, the lower nitride-based cladding layer / the nitride-based active layer / the upper nitride-based cladding layer / superlattice structure 20, 30, 40, and 90 formed of the Group III nitride-based semiconductor single crystal are formed by MOCVD, MBE, HVPE, , Or a device such as a PLD. In order to improve the lattice matching with the sapphire growth substrate 10 prior to the growth of the n-type In x Al y Ga 1-xy N semiconductor of the lower nitride-based cladding layer 20, The buffer layer 201 may be formed therebetween.

However, the material used for the ohmic contact current spreading layer (501 or 60) composed of the transparent electroconductive material located on the upper surface of the upper nitride-based clad layer (40) has a trade-off relationship between the transmittance and the electric conductivity have. That is, if the thickness of the ohmic contact current spreading layer (501 or 60) is decreased to increase the transmittance, the conductivity of the ohmic contact current spreading layer (501 or 60) is lowered. Conversely, the conductivity of the group III nitride- This causes a problem of degradation of device reliability.

Therefore, as a method of not using an ohmic contact current spreading layer composed of a transparent electrically conductive material, in the case of an optically transparent growth substrate, an electrically conductive material having a high reflectance is formed on the upper surface of the nitride- The ohmic contact current spreading layer 502 may be formed. This is a cross-sectional view of a group III nitride-based semiconductor light-emitting diode device having a flip-chip structure shown in Fig.

As shown in the figure, a group III nitride-based semiconductor light-emitting diode device having a flip chip structure includes an optically transparent sapphire growth substrate 10 and a lower portion made of an n-type conductive semiconductor material sequentially grown on the growth substrate 10 A nitride-based clad layer 20, a nitride-based active layer 30, and a top nitride-based clad layer 40 made of a p-type conductive semiconductor material. An ohmic contact current spreading layer 502 made of an electrically conductive material having a high reflectance is formed on the upper nitride-based cladding layer 40, and light generated in the nitride-based active layer 30, which is a light emitting structure for a light- Is reflected in the opposite direction by using the ohmic contact current spreading layer 502 having a high reflectivity and is emitted toward the optically transparent growth substrate 10. [

Generally, a light emitting diode device widely used by using group III nitride-based semiconductors is generated from ultraviolet to blue to green by using InGaN or AlGaN in the nitride-based active layer 30, 10) sapphire. Since the sapphire used as the growth substrate 10 has a considerably wide band gap, it is transparent to light emitted from the group III nitride-based semiconductor light-emitting diode device. Therefore, the flip chip structure described above can be said to be a very effective means, especially in the group III nitride-based semiconductor light-emitting diode device. However, the flip-chip structure can form a ohmic contact interface with the upper nitride- Are limited. Typically, silver (Ag), aluminum (Al), and rhodium (Rh) are representative metal materials having high reflectance. The silver (Ag), the rhodium (Rh), and the alloys associated therewith exhibit a good ohmic contact interface with the upper nitride-based cladding layer (40), but the metal or alloy of these materials may emit light Diffusion phenomenon of material movement into the structure occurs, and there is a problem that the operating voltage of the light emitting diode device rises and reliability is lowered. In addition, the thermally unstable silver (Ag), rhodium (Rh), and alloys associated therewith exhibit low reflectance for ultraviolet rays of a short wavelength region of 400 nm or less, and the ohmic contact current of the light emitting diode device for ultraviolet light But not as a material of the spreading layer 502. On the other hand, the aluminum (Al) and related alloys have a high reflectivity up to the ultraviolet region, but they form a schottky contact interface rather than a preferable ohmic contact interface with the upper nitride-based cladding layer 40 having p- There is no state. Therefore, in order to realize a flip-chip group III nitride-based semiconductor light-emitting diode device, an ohmic contact current spreading layer (having an ohmic contact interface and a high reflectivity on the upper surface of the upper nitride- It is necessary to develop a material or a structure capable of forming the substrate 502.

The present invention relates to a nitride-based cladding layer for a Group III nitride-based semiconductor light-emitting diode device, which comprises a p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) Type cladding layer of the light-emitting structure for a group III nitride-based semiconductor light-emitting diode device, in order to solve the problems that arise in forming an ohmic contact current spreading layer having a high reflectivity and an ohmic contact interface, x Al y Ga 1-xy N (0? x, 0? y, x + y? 1) thin film structure composed of a superlattice structure, first, second and third ohmic contact current spreading layers on the semiconductor surface Group III nitride-based semiconductor light-emitting diode device having a flip-chip structure having a low driving voltage, a low leakage current, and a high external light-emitting efficiency characteristic, and a method of manufacturing the same.

The present invention relates to a semiconductor device comprising: a growth substrate; A lower nitride-based clad layer made of an n-type conductive group III nitride-based semiconductor, a nitride-based active layer made of another group III nitride-based semiconductor material, and a p-type conductive group III nitride-based semiconductor on the upper surface of the growth substrate A light-emitting structure for a light-emitting diode element comprising a top nitride-based clad layer; A superlattice structure formed on the upper surface of the light emitting structure for the light emitting diode device; And a thin film structure composed of first, second, and third ohmic contact current spreading layers formed on the top surface of the superlattice structure,

The superlattice structure is a multi-layer structure composed of Group 2, Group 3, or Group 4 nitrides having different dopants and compositional elements,

Wherein the ohmic contact current spreading layer comprises a group III nitride based conductive thin film structure which is a first ohmic contact current spreading layer, a transparent conductive thin film structure which is a second ohmic contact current spreading layer, a reflective layer which is a third ohmic contact current spreading layer, And a conductive thin-film structure. The group III nitride-based semiconductor light-emitting diode device includes a conductive thin film structure.

The superlattice structure is a multi-layer composed of Group 2, Group 3 or Group 4 nitrides having different dopants and compositional elements,

And a light extraction structure in which a surface irregularity process is introduced on the top surface of the first or second ohmic contact current spreading layer in order to improve light extraction efficiency by changing incident angle of light generated in the light emitting diode device Another group III nitride-based semiconductor light-emitting diode device is proposed.

The present invention provides, as a constituent means for achieving the above-mentioned object, a light emitting device using group III nitride-based semiconductor represented by the formula In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) A method of manufacturing a diode (hereinafter, referred to as a group III nitride-based semiconductor light-emitting diode)

Preparing a growth substrate for growing a light-emitting structure for a group III nitride-based semiconductor light-emitting diode device;

A nitride-based active layer made of a group III nitride-based semiconductor material having a different composition, and a nitride-based active layer made of a p-type conductive group III nitride semiconductor material Forming a light emitting structure for a group III nitride-based semiconductor light-emitting diode device in which a top nitride-based clad layer made of a nitride-based semiconductor material is successively stacked and grown;

Forming a superlattice structure on a semiconductor upper surface of a p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductor which is the upper nitride-based cladding layer of the light- ;

Forming a first ohmic contact current spreading layer on the superlattice structure;

Forming a second ohmic contact current spreading layer on top of the first ohmic contact current spreading layer;

Forming a third ohmic contact current spreading layer on top of the second ohmic contact current spreading layer;

Removing a portion of the first, second and third ohmic contact current spreading layers, the superlattice structure, the upper nitride-based clad layer, the nitride-based clad layer, and the lower nitride- Forming an n-type ohmic contact electrode and an electrode pad on a part of the upper surface of the lower nitride-based clad layer; And

And forming a p-type schottky contact electrode and an electrode pad on a part of the upper surface of the first, second, or third ohmic contact current spreading layer.

The present invention provides, as still another constituent means for achieving the above-mentioned object, a group III nitride-based semiconductor represented by the formula In x Al y Ga 1-xy N (0? X, 0? Y, x + (Hereinafter referred to as a group III nitride-based semiconductor light-emitting diode) element,

Removing a portion of the first and second ohmic contact current spreading layers, the superlattice structure, the upper nitride-based clad layer, the nitride-based active layer, and the lower nitride-based clad layer and exposing the lower nitride- Next, an n-type ohmic contact electrode and an electrode pad are formed on a part of the upper surface of the lower nitride-based clad layer.

Forming a third ohmic contact current spreading layer on top of the second ohmic contact current spreading layer; And

Removing a portion of the first ohmic contact current spreading layer, the superlattice structure, the upper nitride-based clad layer, the nitride-based active layer, and the lower nitride-based clad layer, exposing the lower nitride-based clad layer to the atmosphere, Forming an n-type ohmic contact electrode and an electrode pad on a part of the upper surface of the lower nitride-based clad layer;

Forming a second ohmic contact current spreading layer on the top surface of the first ohmic contact current spreading layer

Alternatively, instead of the multi-layered superlattice structure, a superlattice structure of an n-type conductive InGaN single layer or a p-type conductive InGaN single layer having a thickness of 5 nm or less may be formed.

Wherein the ohmic contact current spreading layer comprises a first ohmic contact current spreading layer of a Group III nitride based conductive thin film structure, a second ohmic contact current spreading layer of a transparent conductive thin film structure, a third ohmic contact current spreading layer of a reflective conductive thin film structure, And a spreading layer.

Before forming the third ohmic contact current spreading layer, a light extracting structure in which surface irregularities are introduced on the top surface of the first or second ohmic contact current spreading layer composed of the group III nitride-based conductive thin film structure is formed It is possible.

The lower nitride-based clad layer, the nitride-based active layer, the upper nitride-based clad layer, the superlattice structure, and the first ohmic contact current spreading layer may be formed in situ using MOCVD, MBE, or HVPE equipment. Grow continuously.

In addition, the lower nitride-based clad layer, the nitride-based active layer, the upper nitride-based clad layer, and the superlattice structure are successively grown in an in-situ state using MOCVD, MBE, or HVPE equipment, The first ohmic contact current spreading layer may be formed in an ex situ state by using MOCVD, MBE, HVPE, sputter, evaporator or PLD equipment.

As described above, the present invention provides a group III nitride-based semiconductor light-emitting device (light-emitting diode) element having a flip chip structure, wherein the upper nitride-based cladding layer of the flip chip structure light- a first ohmic contact current spreading layer composed of a superlattice structure, a group III nitride-based conductive thin film structure, and a transparent conductive thin film layer on the semiconductor upper surface of y Ga 1-xy N (0? x, 0? y, And a third ohmic contact current spreading layer composed of a reflective conductive thin film structure to improve the light transmittance characteristic of the entire LED chip having a good flip chip structure, And the luminance of the light emitting element can be improved.

In addition, in a group III nitride-based semiconductor light-emitting diode device having a flip chip structure having a light extracting structure, a first or a second ohmic contact current spreading layer made of a group III nitride- based conductive thin film structure by wet or dry etching Since the surface irregularities can be easily formed on the upper surface, the total reflection light can be minimized inside the structure of the light emitting structure for a flip chip structure, so that the entire luminance characteristics of the LED device can be further improved.

Hereinafter, the group III nitride-based semiconductor light-emitting diode device manufactured according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view showing a first embodiment of a light-emitting structure for a group III nitride-based semiconductor light-emitting diode device having a flip chip structure invented by the present invention.

Referring to FIG. 1, a light emitting structure A for a light emitting diode device having a flip chip structure according to a first embodiment of the present invention, which is grown on a growth substrate 10, A nitride-based active layer 30, an upper nitride-based cladding layer 40 made of a p-type conductive semiconductor material, and a lower nitride-based cladding layer 20 made of an n-type conductive semiconductor material, A superlattice structure 90, and a first ohmic contact current spreading layer 100.

The growth substrate 10 may be made of a material such as sapphire or silicon carbide (SiC).

The lower nitride-based clad layer 20 made of the n-type conductive semiconductor material may be formed of In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductor multi- And a buffer layer (not shown) formed on the upper surface of the growth substrate 10. The lower nitride-based clad layer 20 may be formed by doping silicon (Si).

The nitride-based active layer 30 is a region where carriers such as electrons and holes are recombined, and includes InGaN, AlGaN, GaN, AlInGaN, and the like.

The nitride-based active layer 30 may be a multilayer film in which a quantum well layer and a barrier layer are repeatedly formed. The energy band gap of the material constituting the barrier layer of the nitride based active layer 30 is larger than the energy band gap of the material constituting the well layer and the thickness of the barrier layer is greater than the thickness of the well layer Thick is common. The barrier layer and the well layer may be binary, ternary or quaternary compound nitride semiconductors represented by the formula In x Al y Ga 1-xy N (0? X, 0? Y, x + have. Furthermore, the barrier layer and the well layer may be formed by doping silicon (Si), magnesium (Mg), or the like. The emission wavelength of light emitted from the light emitting diode device is determined according to the kind of the material constituting the quantum well layer of the nitride-based active layer 30. [

The upper nitride-based clad layer 40 made of the p-type conductive semiconductor material may be formed of a p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + have. The upper nitride-based clad layer 40 may be formed by doping zinc (Zn) or magnesium (Mg).

The superlattice structure 90 is formed on the upper surface of the upper nitride-based clad layer 40 made of the p-type conductive semiconductor material, and includes p-type p-type In x Al y Ga 1-xy N (0? y, x + y < / = 1) to increase the effective hole concentration by lowering the activation energy of the semiconductor dopant, or by quantum-mechanical tunneling transport phenomenon through energy band gap control Can cause.

The superlattice structure 90 is generally formed in a multi-layer structure. The thickness of each layer constituting the superlattice structure 90 is 5 nm or less, and each layer is made of InN, InGaN, InAlN, AlGaN, GaN, AlInGaN, AlN, SiC, SiCN , MgN, ZnN, or SiN. For example, the superlattice structure 90 includes InGaN / GaN, AlGaN / GaN, InGaN / GaN / AlGaN, and AlGaN / GaN / InGaN.

Further, each layer of the superlattice structure 90 may be formed by doping silicon (Si), magnesium (Mg), zinc (Zn), or the like.

A superlattice structure 90 composed of an n-type conductive InGaN single layer or a p-type conductive InGaN single layer having a thickness of 5 nm or less may be used instead of the multi-layered superlattice structure 90 have.

The first ohmic contact current spreading layer 100 is composed of a group III nitride-based conductive thin film structure. The group III nitride-based conductive thin-film structure of the first ohmic contact current spreading layer 100 is represented by the formula In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) And may be configured as a single layer or a multi-layer having a thickness of 6 nm or more. Furthermore, the first ohmic contact current spreading layer 100 may be formed by doping silicon (Si), magnesium (Mg), zinc (Zn), or the like.

The light-emitting structure A for a light-emitting diode device having the flip chip structure is continuously grown in an in-situ state by using an apparatus such as MOCVD, MBE, HVPE, sputter, or PLD. The nitride-based active layer 30, the upper nitride-based clad layer 40, and the superlattice structure 90 of the light-emitting structure A for the light-emitting diode element of the flip-chip structure, The first ohmic contact current spreading layer 100 may be grown on the upper surface of the superlattice structure 90 in an ex situ state after the first in-situ growth.

FIG. 2 is a cross-sectional view showing a second embodiment of a light-emitting structure for a group III nitride-based semiconductor light-emitting diode device of a flip chip structure invented by the present invention.

Referring to FIG. 2, a light emitting structure B for a light emitting diode device having a flip chip structure according to a first embodiment of the present invention, which is grown on a growth substrate 10, A nitride-based active layer 30, an upper nitride-based cladding layer 40 made of a p-type conductive semiconductor material, and a lower nitride-based cladding layer 20 made of an n-type conductive semiconductor material, Repeatedly stacked superlattice structures 90 and a first ohmic contact current spreading layer 100.

The superlattice structure 90 repeatedly stacked on the upper nitride-based cladding layer 40 is located on the upper surface of the upper nitride-based cladding layer 40 made of the p-type conductive semiconductor material, and the p-type p-type In x Al y Ga 1-xy N (0? x, 0? y, x + y? 1) to increase the effective hole concentration by lowering the dopant activation energy of the semiconductor, or to control the energy band gap Can lead to quantum-mechanical tunneling transport phenomena.

The first ohmic contact current spreading layer 100 repeatedly stacked on the superlattice structure 90 is composed of a group III nitride-based conductive thin film structure. The group III nitride-based conductive thin-film structure of the first ohmic contact current spreading layer 100 is represented by the formula In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) And may be configured as a single layer or a multi-layer having a thickness of 6 nm or more. Furthermore, the first ohmic contact current spreading layer 100 may be formed by doping silicon (Si), magnesium (Mg), zinc (Zn), or the like.

The light emitting structure B for the light emitting diode element having the flip chip structure is continuously grown in an in-situ state by using an apparatus such as MOCVD, MBE, HVPE, sputter, or PLD. The nitride-based active layer 30, the upper nitride-based clad layer 40, and the superlattice structure 90 of the light-emitting structure B for the light-emitting diode element of the flip-chip structure, The first ohmic contact current spreading layer 100 is grown on the upper surface of the superlattice structure 90 in an ex situ state in a continuous in- .

3 is a cross-sectional view of a group III nitride-based semiconductor light emitting diode device having a flip chip structure as a first embodiment manufactured by the present invention.

Referring to FIG. 3, a light emitting structure A for a light emitting diode device having a flip chip structure according to the first embodiment of the present invention is grown on an upper surface of a growth substrate 10. In other words, on the upper surface of the growth substrate 10, a lower nitride-based clad layer 20 made of an n-type conductive semiconductor material including a buffer layer (not shown), a nitride-based active layer 30, A light emitting structure A for a light emitting diode element composed of a nitride-based clad layer 40, a superlattice structure 90 and a first ohmic contact current spreading layer 100, a second ohmic contact current spreading layer 120, A third ohmic contact current spreading layer 130, a p-type schottky contact electrode and an electrode pad 70, and an n-type ohmic contact electrode and an electrode pad 80.

For example, the lower nitride-based clad layer 20, the nitride-based active layer 30, the upper nitride-based clad layer 40, the superlattice structure 90, and the first ohmic contact current spreading layer 100 The second and third ohmic contact current spreading layers 130 are grown in-situ using MOCVD, MBE, or HVPE equipment, and the second and third ohmic contact current spreading layers 130 are formed using sputter, evaporator, or PLD equipment It is preferably formed in an ex situ state.

The light emitting diode device has a structure in which the lower nitride-based clad layer 20, the nitride-based active layer 30, and the upper nitride-based clad layer 40 are continuously laminated. The nitride-based active layer 30 is formed on a part of the lower nitride-based clad layer 20 made of the n-type conductive semiconductor material, and the nitride-based active layer 30 is formed of a p- The upper nitride-based cladding layer 40 is formed. Accordingly, a part of the upper surface of the lower nitride-based cladding layer 20 is bonded to the nitride-based active layer 30, and the remaining part of the upper surface is exposed to the outside.

The superlattice structure 90 is located in a part or the whole area of the upper surface of the upper nitride-based clad layer 40 and is generally formed in a multi-layered structure. The thickness of each layer constituting the superlattice structure 90 is 5 nm or less, May be composed of InN, InGaN, InAlN, AlGaN, GaN, AlInGaN, AlN, SiC, SiCN, MgN, ZnN, or SiN. For example, the superlattice structure 90 may include silicon-doped InGaN / GaN, AlGaN / GaN, InGaN / GaN / AlGaN, and AlGaN / GaN / InGaN.

The first ohmic contact current spreading layer 100 is formed of a Group III nitride-based conductive thin film structure in a part or the entire region of the superlattice structure 90, Transmits light to the outside. For example, a group III nitride-based conductive material such as silicon (Si) -doped GaN having a sheet resistance of 50? /? Or less, silicon-doped aluminum gallium nitride (AlGaN) , MBE, HVPE, sputter, PLD, or the like, and has a thickness of 6 nm or more. The current is uniformly distributed through the p-type Schottky contact electrode and the electrode pad 70, And to increase the efficiency.

The second ohmic contact current spreading layer 120 is formed of a transparent conductive thin film structure. The transparent conductive thin film structure of the second ohmic contact current spreading layer 120 has a light transmittance of 70% or more in a wavelength band of 600 nm or less, such as ITO or ZnO, and has a sheet resistance of 50 Ω / Or a multi-layer having a thickness equal to or greater than the thickness of the substrate.

The third ohmic contact current spreading layer 130 is formed of a reflective conductive thin film structure. The reflective conductive thin film structure of the third ohmic contact current spreading layer 130 has a light reflectance of 70% or more in a wavelength band of 600 nm or less, such as Ag or Al, and has a sheet resistance of 50? /? Or a multi-layer having a thickness equal to or greater than the thickness of the substrate.

The p-type schottky contact electrode and the electrode pad 70 are located on a part of the upper surface of the ohmic contact current spreading layer 100, 120, or 130, and the ohmic contact current spreading layer 100, 120, And a material for forming a schottky contact interface, for example, a metal such as Pd / Au, and may be formed by a lift off method. Pd / Au may be used to improve the adhesion of the ohmic contact current spreading layer 100, 120, or 130 as well as to improve the adhesion of the ohmic contact current spreading layer 100, 120, A contact interface can be obtained.

The n-type ohmic contact electrode and the electrode pad 80 are formed on the exposed surface of the lower nitride-based clad layer 20 made of an n-type conductive semiconductor material and can be formed using a lift-off method. The n-type ohmic contact electrode and the electrode pad 80 are made of a metal such as Cr / Al to form an ohmic contact interface with the lower nitride-based clad layer 20, The adhesion can be improved and an ohmic contact interface with the lower nitride-based clad layer 20 can be obtained.

4 is a cross-sectional view of a group III nitride-based semiconductor light emitting diode device having a flip chip structure as a second embodiment manufactured by the present invention.

Referring to FIG. 4, a light emitting structure A for a light emitting diode element having a flip chip structure according to the first embodiment of the present invention is grown on the growth substrate 10. In other words, on the upper surface of the growth substrate 10, a lower nitride-based clad layer 20 made of an n-type conductive semiconductor material including a buffer layer (not shown), a nitride-based active layer 30, A light emitting structure A for a light emitting diode element composed of a nitride-based clad layer 40, a superlattice structure 90, a first ohmic contact current spreading layer 100, and a light extracting structure 110, A current spreading layer 130, a p-type schottky contact electrode and an electrode pad 70, and an n-type ohmic contact electrode and an electrode pad 80.

For example, the lower nitride-based clad layer 20, the nitride-based active layer 30, the upper nitride-based clad layer 40, the superlattice structure 90, and the first ohmic contact current spreading layer 100 MOCVD, MBE, HVPE, sputter, evaporator, or PLD device. The MOCVD, MBE, HVPE, or HVPE device is used to continuously grow the in- It is preferable to form it in an ex situ state.

The light extracting structure 110 is formed on the upper surface of the first or second ohmic contact current spreading layer 100 or 120 to emit light generated in the nitride based active layer 30 as much as possible into the atmosphere. It is a surface texture. The light extracting structure 110 may be formed on the surface of the first or second ohmic contact current spreading layer 100 or 120 by wet or dry etching to form irregularities having a predetermined shape and dimensions, It is possible to minimize the total reflection light to the inside of the structure structure, thereby further improving the overall luminance characteristic of the LED device.

The p-type schottky contact electrode and the electrode pad 70 are located on a part of the upper surface of the light extracting structure 110 or the ohmic contact current spreading layer 100, 120, or 130, and the light extracting structure 110 or For example, Pd / Au, for forming a schottky contact interface with the ohmic contact current spreading layer 100, 120, or 130, and may be formed by a lift off method. Pd / Au may be used to improve the adhesion of the light extraction structure 110 or the ohmic contact current spreading layer 100, 120, or 130, A schottky contact interface of the current spreading layer 100, 120, or 130 can be obtained.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. Accordingly, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also within the scope of the present invention.

1 is a cross-sectional view showing a first embodiment of a light-emitting structure for a group III nitride-based semiconductor light-emitting diode device having a flip chip structure invented by the present invention,

FIG. 2 is a cross-sectional view showing a second embodiment of a light-emitting structure for a group III nitride-based semiconductor light-emitting diode device having a flip chip structure invented by the present invention,

3 is a cross-sectional view showing a first embodiment of a group III nitride-based semiconductor light-emitting diode device having a flip chip structure manufactured according to the present invention,

4 is a cross-sectional view illustrating a flip chip structure group III nitride-based semiconductor light emitting diode device according to a second embodiment of the present invention,

5 is a cross-sectional view showing a typical example of a conventional Group III nitride-based semiconductor light-emitting diode device,

6 is a cross-sectional view for explaining a comparison between a multi-quantum well structure and a superlattice structure,

FIG. 7 is a cross-sectional view showing a typical example of a conventional Group III nitride-based semiconductor light-emitting diode device,

FIG. 8 is a cross-sectional view showing a representative example of a conventional group III nitride-based semiconductor light emitting diode device having a flip chip structure.

Claims

A growth substrate;

A nitride-based active layer made of an n-type conductive semiconductor material including a buffer layer formed on the upper surface of the growth substrate, a nitride-based active layer, and a nitride-based clad layer made of a p-type conductive semiconductor material; ;

A superlattice structure formed on a part or the whole area of the upper nitride-based clad layer of the light-emitting structure for the light-emitting diode device;

A first ohmic contact current spreading layer formed of a group III nitride-based conductive thin-film structure on a part or whole of the upper surface of the superlattice structure;

A third ohmic contact current spreading layer that is a reflective conductive thin film structure disposed on the first ohmic contact current spreading layer;

A p-type schottky contact electrode and an electrode pad formed on a part of the upper surface of the first ohmic contact current spreading layer or the third ohmic contact current spreading layer; And

And an n-type Ohmic contact electrode and an electrode pad formed on a part of the upper surface of the lower nitride-based clad layer of the light emitting structure for the light emitting diode device

Wherein the first ohmic contact current spreading layer has a light extracting structure in at least a part of a region of a group III nitride-based semiconductor light emitting diode device having a flip chip structure.

The method according to claim 1,

Wherein the superlattice structure is a multilayer film in which two layers or three layers are periodically repeated with one pair formed.

3. The method of claim 2,

Wherein each layer of the superlattice structure has a thickness of 5 nm or less and is made of InN, InGaN, InAlN, AlGaN, GaN, AlInGaN, AlN, SiC, SiCN, MgN, ZnN, Group nitride semiconductor light emitting diode device.

The method of claim 3,

Wherein each layer of the superlattice structure is a material doped with silicon (Si), magnesium (Mg), or zinc (Zn), and the group III nitride-based semiconductor light emitting diode device of the flip chip structure.

The method according to claim 1,

The superlattice structure may be replaced with an n-type conductive InGaN single layer or a p-type conductive InGaN single layer having a thickness of 5 nm or less. The flip chip structure group III nitride-based semiconductor Light emitting diode device.

The method according to claim 1,

Wherein the first ohmic contact current spreading layer is formed of a group III nitride-based conductive thin film structure having a thickness of 6 nm or more.

The method according to claim 1,

The group III nitride-based conductive thin film structure constituting the first ohmic contact current spreading layer is formed of a material represented by the formula In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) Type nitride semiconductor light-emitting diode device having a flip-chip structure.

The method according to claim 1,

Further comprising a second ohmic contact current spreading layer that is a transparent conductive thin film structure disposed between the first ohmic contact current spreading layer and the third ohmic contact current spreading layer,

Wherein the second ohmic contact current spreading layer is formed of a transparent conductive thin film structure having a light transmittance of 70% or more in a wavelength band of 600 nm or less and a sheet resistance of 50? /? Or less and a group III nitride of a flip chip structure Semiconductor light emitting diode device.

9. The method of claim 8,

Wherein the second ohmic contact current spreading layer is composed of a single layer or a multi-layer having a thickness of 5 nm or more.

The method according to claim 1,

Wherein the third ohmic contact current spreading layer is formed of a reflective conductive thin film structure having a light reflectance of 70% or more and a sheet resistance of 50 Ω / □ or less in a wavelength band of 600 nm or less, Semiconductor light emitting diode device.

The method according to claim 1,

Wherein the third ohmic contact current spreading layer is composed of a single layer or a multi-layer having a thickness of 200 nm or more.

A growth substrate;

A first ohmic contact common spreading layer formed on a part or the entire region of the superlattice structure;

A light extracting structure formed on a part or the whole area of the upper surface of the first ohmic contact current spreading layer;

A second ohmic contact current spreading layer formed on the top surface of the light extracting structure;

A third ohmic contact current spreading layer formed on the upper surface of the second ohmic contact current spreading layer;

A p-type schottky contact electrode and an electrode pad formed on a part of the upper surface of the light extracting structure, the first, second, or third ohmic contact current spreading layer; And

And an n-type ohmic contact electrode and an electrode pad formed on a part of the upper surface of the lower nitride-based clad layer of the light-emitting structure for the light-emitting diode device, and a p-type nitride group III nitride semiconductor light-emitting diode device.

13. The method of claim 12,

15. The method of claim 14,

Wherein each layer of the superlattice structure is a material doped with silicon (Si), magnesium (Mg), or zinc (Zn).

13. The method of claim 12,

The group III nitride-based conductive thin film structure constituting the first ohmic contact current spreading layer may be a nitride-based conductive thin film structure having a composition expressed by the formula In x Al y Ga 1-xy N (0? X, 0? Y, x + y? Type nitride semiconductor light-emitting diode device having a flip chip structure characterized by being a single layer or multilayer film of water.

13. The method of claim 12,

Wherein the second ohmic contact current spreading layer is formed of a transparent conductive thin film structure having a light transmittance of 70% or more in a wavelength band of 600 nm or less and a sheet resistance of 50? /? Or less, and a group III nitride- Semiconductor light emitting diode device.

13. The method of claim 12,

And the second ohmic contact current spreading layer is composed of a single layer or a multi-layer having a thickness of 5 nm or more, and the flip chip structure of the group III nitride-based semiconductor light-emitting diode device.

13. The method of claim 12,

Wherein the third ohmic contact current spreading layer is formed of a reflective conductive thin film structure having a light reflectance of 70% or more at a wavelength band of 600 nm or less and a sheet resistance of 50? /? Or less, and a group III nitride- Semiconductor light emitting diode device.

13. The method of claim 12,

Wherein the third ohmic contact current spreading layer is composed of a single layer or a multi-layer having a thickness of 200 nm or more, and the flip chip structure of the group III nitride-based semiconductor light emitting diode device.

13. The method of claim 12,

Wherein the light extracting structure has a texture having a predetermined shape and dimensions formed on an upper surface of the second ohmic contact current spreading layer.

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