KR101480552B1

KR101480552B1 - group 3 nitride-based semiconductor light emitting diodes and methods to fabricate them

Info

Publication number: KR101480552B1
Application number: KR20080033967A
Authority: KR
Inventors: 송준오
Original assignee: 엘지이노텍 주식회사
Priority date: 2008-04-12
Filing date: 2008-04-12
Publication date: 2015-01-08
Also published as: KR20090108506A

Abstract

The present invention is characterized in that it comprises a thin film structure composed of a first and a second ohmic contact current spreading layer 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 Group III nitride-based semiconductor light-emitting diode device 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- Prior to growing the ohmic contact current spreading layer composed of the group III nitride-based conductive thin film structure as the ohmic contact current spreading layer and the transparent conductive thin film structure as the second ohmic contact current spreading layer, the upper nitride- (0? X, 0? Y, x + y? 1) semiconductor layer and p-type In x Al y Ga 1-xy N So that the overall performance of the light emitting diode device including the driving voltage and the external light emitting efficiency can be effectively improved.

Group III nitride-based semiconductor light-emitting diode device, group III nitride-based conductive thin film structure, transparent conductive thin film structure, ohmic contact current spreading layer, light extracting structure, surface irregularity

Description

Group III nitride-based semiconductor light-emitting diode device and a method of manufacturing 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 + Before forming the ohmic contact current spreading layer composed of the group III nitride-based conductive thin film structure as the spreading layer and the transparent conductive thin film structure as the second ohmic contact current spreading layer, the p-type A superlattice structure is formed between the thin film structure composed of In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductor and first and second ohmic contact current spreading layers. So that the current injection in the vertical direction is facilitated and the surface irregularity process is introduced on the top surface of the ohmic contact current spreading layer to effectively perform the overall performance of the light emitting diode device including the driving voltage and the external light emitting efficiency Improving Kiel can.

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 the 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, Lt; RTI ID = 0.0 > 50 < / 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- Nickel-gold (NiO), which is oxidized to form an ohmic contact current spreading layer 50 which forms an ohmic contact interface with low contact resistance in the vertical direction before forming the p-type electrode 80 on the upper surface, (Ni-O-Au).

The ohmic contact current spreading layer 50 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 50 made of oxidized nickel-gold shows an average transmittance as low as 70% even after heat treatment, and this 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-luminance light-emitting diode device through a high light transmittance of the ohmic contact current spreading layer 50, a variety of semiconductors including the oxidized nickel-gold (Ni-O- 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, has been proposed instead of the Ohmic contact current spreading layer 50 formed of a transparent metal or an alloy. 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- In recent years, YK Su et al. Have reported that the above-mentioned transparent electroconductive material can be used as a good ohmic contact current spreading layer 50 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) 50) formation technology.

6, the superlattice structure has 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 thicker than that of the well (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 a semiconductor multilayer of p-type In x Al y Ga 1-x-y N (0? X, 0? Y, x + y? 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.

In addition, the energy conversion efficiency (lm / W) of the packaged light emitting diode device can be increased by extracting as much light as possible from the active layer in the light emitting structure for the group III nitride-based semiconductor light emitting diode device. Generally, the external luminous efficiency of the group III nitride-based semiconductor light-emitting diode is surprisingly low. This is because a large difference in refractive index between the group III nitride-based semiconductor such as GaN or the ohmic contact current spreading layer such as ITO or ZnO and the molding material causes a substantial part of the light generated in the LED structure to be emitted to the outside The light is totally reflected and then proceeds to the inner side of the LED again to be destroyed. For example, assuming that gallium nitride (GaN) has a refractive index of about 2.3 and a refractive index of a molding material of about 1.5, the amount of light totally reflected on the junction surface of the two materials is about 90% In order to solve this problem, a p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y The surface of the semiconductor or ohmic contact current spreading layer 60 is subjected to an etching process to introduce a surface texture having a predetermined shape and dimension to the surface. In this case, it was confirmed that the light extraction efficiency was significantly improved.

However, the p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductor or the ohmic contact current spreading layer 60 which is the upper nitride- The step of introducing the irregularities may be performed by forming the upper nitride-based cladding layer 40 of p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) semiconductors or ohmic contact current spreading layers There is a possibility of causing electrical damage to the surface of the LED 60, thereby raising the driving voltage and the leakage current of the LED device, thereby deteriorating the energy conversion efficiency.

The present invention relates to a p-type In x Al y Ga 1-xy N (0? X, 0? Y, x + y? 1) upper cladding layer of a light emitting structure for a group III nitride- In order to solve the problems caused by the formation of the ohmic contact current spreading layer and the introduction of the surface irregularities, there has been proposed a method for forming a p-type In x Al y Ga 4 -type cladding layer of the Group III nitride- 1-xy N (0? X, 0? Y, x + y? 1) semiconductor thin film structure composed of a superlattice structure and first and second ohmic contact current spreading layers is sequentially formed, A low leakage current, and a high external luminous 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 and second 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 nitride 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 and a transparent conductive thin film structure which is a second ohmic contact current spreading layer. A semiconductor light emitting diode device is proposed.

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 extracting structure in which a surface irregularity process is introduced on the top surface of the ohmic contact current spreading layer in order to improve the light extraction efficiency by changing the incident angle of light generated in the light emitting diode device. Nitride semiconductor light-emitting diode device.

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;

Removing a portion of the first and second ohmic contact current spreading layers, the superlattice structure, the upper nitride-based clad 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 top surface of a region of the nitride-based clad layer; And

And forming a p-type schottky contact electrode and an electrode pad on a top surface of a part of the ohmic contact current spreading layer region.

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,

Forming a light extraction structure in which a surface irregularity process is introduced on an upper surface of the second ohmic contact current spreading layer;

Removing a portion of the light extraction structure, the first and second ohmic contact current spreading layers, the superlattice structure, the upper nitride-based clad 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 the upper surface of a part of the lower nitride-based clad layer. And

And forming a p-type schottky contact electrode and an electrode pad on a surface of the light extraction structure or a part of the ohmic contact current spreading layer.

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 instead of the multi-layered superlattice structure.

The ohmic contact current spreading layer is composed of a group III nitride-based conductive thin film structure and a transparent conductive thin film structure.

The lower nitride-based cladding layer, the nitride-based active layer, the upper nitride-based cladding layer, the superlattice structure, and the first and second ohmic contact current spreading layers are formed in-situ using MOCVD, MBE, or HVPE equipment. ). &Lt; / RTI >

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 and second ohmic contact current spreading layers may be formed in an ex situ state using MOCVD, MBE, HVPE, sputter, evaporator or PLD equipment.

As described above, the present invention relates to a group III nitride-based semiconductor light-emitting device (light-emitting diode) element, wherein the upper nitride-based clad layer of the light- A first ohmic contact current spreading layer composed of a superlattice structure, a group III nitride-based conductive thin film structure, and a second ohmic contact current spreading layer composed of a transparent conductive thin film structure on the semiconductor upper surface, There is an excellent effect that the current spreading layer is grafted to improve the luminance of the light emitting device in which the light transmittance characteristic is improved in addition to the good electrical characteristics of the good LED device as a whole.

In addition, in the group III nitride-based semiconductor light-emitting diode device having a light extracting structure, a first ohmic contact current spreading layer or a transparent conductive thin film structure composed of a group III nitride-based conductive thin film structure is formed by wet or dry etching It is possible to easily form the surface irregularities on the upper surface of the second ohmic contact current spreading layer, thereby minimizing the total reflection inside the structure of the light emitting structure for the LED device, thereby improving the overall luminance characteristic of the LED device have.

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 illustrating a first embodiment of a light emitting structure for a group III nitride-based semiconductor light emitting diode device developed by the present invention.

Referring to FIG. 1, a light emitting structure A for a light emitting diode device according to a first embodiment of the present invention, which is grown on a growth substrate 10, includes a buffer layer (not shown) The nitride-based active layer 30, the upper nitride-based clad layer 40 made of a p-type conductive semiconductor material, and the 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 of the well layer and the thickness of the barrier layer is larger than the thickness of the well layer It is generally more thick. 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 the light-emitting diode element is continuously grown in an in-situ state using a device such as MOCVD, MBE, HVPE, sputter, or PLD. Further, the lower nitride-based clad layer 20, the nitride-based active layer 30, the upper nitride-based clad layer 40, and the superlattice structure 90 of the light-emitting diode for a light- 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 growth in the sheath state.

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 element, which is invented by the present invention.

Referring to FIG. 2, a light emitting structure B for a light emitting diode device according to a first embodiment of the present invention, which is grown on a growth substrate 10, includes a buffer layer (not shown) A nitride-based active layer 30, a top nitride-based clad layer 40 made of a p-type conductive semiconductor material, and a lower nitride-based clad layer 20 made of an n- A superlattice structure 90 and a first ohmic contact current spreading layer 100.

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 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 A for the light-emitting diode element is continuously grown in an in-situ state using a device such as MOCVD, MBE, HVPE, sputter, or PLD. Further, the lower nitride-based clad layer 20, the nitride-based active layer 30, the upper nitride-based clad layer 40, and the superlattice structure 90 of the light-emitting diode for a light- The first ohmic contact current spreading layer 100 may be grown on the top surface of the superlattice structure 90 in an ex situ state after first growing in an in-situ state .

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

Referring to FIG. 3, a light emitting structure A for a light emitting diode element according to the first embodiment of the present invention is grown on the upper surface of 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, The ohmic contact current spreading layer 100, the second ohmic contact current spreading layer 120, the p-type short-circuit contact electrode, and the electrode pad 70 are formed on the nitride-based cladding layer 40, the superlattice structure 90, And an n-type ohmic contact electrode and an electrode pad (80).

The upper 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 are formed by MOCVD, MBE , Or HVPE equipment and the second ohmic contact current spreading layer 120 is grown using an MOCVD, MBE, HVPE, 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 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 or 120 and form a schottky contact interface with the ohmic contact current spreading layer 100 or 120 For example, a metal such as Pd / Au, and may be formed by a lift off method. Pd / Au can be used to improve adhesion to the ohmic contact current spreading layer 100 or 120, as well as to obtain a shallow contact interface of the ohmic contact current spreading layer 100 or 120, .

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 as a second embodiment manufactured by the present invention.

Referring to FIG. 4, a light emitting structure A for a light emitting diode element 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, The nitride based cladding layer 40, the superlattice structure 90, the first ohmic contact current spreading layer 100, the second ohmic contact current spreading layer 120, the light extracting structure 110, the p- An electrode and an electrode pad 70, and an n-type ohmic contact electrode and an electrode pad 80.

The first ohmic contact current spreading layer 100 is formed of a Group III nitride-based conductive thin film structure on a part or the entire region of the superlattice structure 90, and the nitride- 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 light extracting structure 110 may include a surface texture introduced into the upper surface of the 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. to be. The light extracting structure 110 may be formed by using wet or dry etching on the surface of the ohmic contact current spreading layer 100 or 120 to form irregularities having a predetermined shape and dimensions, The total luminance characteristic of the LED element can be further improved.

The p-type schottky contact electrode and the electrode pad 70 are located in a part of the upper surface of the light extracting structure 110 or the ohmic contact current spreading layer 100 or 120 and the ohmic contact current spreading layer 100 120, and a material such as Pd / Au to form a schottky contact interface, and may be formed by a lift off method. Pd / Au can be used to improve the adhesion of the ohmic contact current spreading layer 100 or 120, as well as to obtain a shock-resistant contact interface of the ohmic contact current spreading layer 100 or 120 .

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 element developed by the present invention,

FIG. 2 is a cross-sectional view illustrating a second embodiment of a light-emitting structure for a group III nitride-based semiconductor light-emitting diode element,

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

FIG. 4 is a cross-sectional view of a 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,

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

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 second ohmic contact current spreading layer which is a transparent electrode formed on a part or whole area of the upper surface of 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 second ohmic contact current spreading layer; 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,

And the second ohmic contact current spreading layer has a light extracting structure on the upper surface thereof.

The method according to claim 1,

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

3. The method of claim 2,

Wherein each layer constituting the superlattice structure is an InN, InGaN, InAlN, AlGaN, GaN, AlInGaN, AlN, SiC, SiCN, MgN, ZnN or SiN material having a thickness of 5 nm or less. Light emitting diode device.

The method of claim 3,

Wherein each layer of the superlattice structure is a material doped with a p-type dopant.

The method according to claim 1,

Wherein the superlattice structure is replaceable with a p-type conductive InGaN single layer having a thickness of 5 nm or less.

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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.

The method according to claim 1,

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 and a sheet resistance of 50? /? Or less in a wavelength band of 600 nm or less. 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.

A growth substrate;

A light extraction structure in which irregularities are introduced on an 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 or the second 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.

11. The method of claim 10,

12. The method of claim 11,

13. The method of claim 12,

Wherein each layer of the superlattice structure is doped with a P-type dopant.

11. The method of claim 10,

Wherein the superlattice structure can 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.

11. The method of claim 10,

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.

11. The method of claim 10,

The group III nitride-based conductive thin film structure constituting the first ohmic contact current spreading layer may include a nitride 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.

11. The method of claim 10,

Wherein the light extracting structure is formed with a texture having a predetermined shape and dimensions on the surface of the first or second ohmic contact current spreading layer.

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

Forming a first ohmic contact current spreading layer as a group III nitride-based conductive thin film structure on the superlattice structure;

Forming a second ohmic contact current spreading layer as a transparent electrode on the top surface of the first ohmic contact current spreading layer;

Removing a portion of the first and second ohmic contact current spreading layers, the superlattice structure, the upper nitride-based clad 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 nitride-based clad layer;

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

Forming a light extracting structure by introducing surface irregularities on an upper surface of the second ohmic contact current spreading layer; Based semiconductor light-emitting diode device.

Removing a portion of the first ohmic contact current spreading layer, the superlattice structure, the upper nitride-based clad layer, and the lower nitride-based clad layer and 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;

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21. The method of claim 20,

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. And the second ohmic contact current spreading layer is formed in an ex-situ state by using MOCVD, MBE, HVPE, sputter, evaporator, or PLD equipment. A method of manufacturing a light emitting diode device.

22. The method of claim 21,

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21. The method of claim 20,

The lower nitride-based clad layer, the nitride-based active layer, the upper nitride-based clad layer, and the superlattice structure may be formed in-situ using MOCVD, MBE, or HVPE equipment, Wherein the current spreading layer and the second ohmic contact current spreading layer are formed in an ex situ state using MOCVD, MBE, HVPE, sputter, evaporator, or PLD equipment. A method of manufacturing a light emitting diode device.

22. The method of claim 21,

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