Title of Invention

NITRIDE SEMICONDCTOR LIGHT EMITTING DEVICE AND FABRICATION METHOD THEREOF

Abstract

A nitride semiconductor light-emitting device according to the present invention comprises a first nitride semiconductor layer; an active layer formed on the first nitride semiconductor layer; a second nitride semiconductor layer formed on the active layer; and a third nitride semiconductor layer having AlIn, which is formed on the second nitride semiconductor layer. And a nitride semiconductor light-emitting device comprises a first nitride semiconductor layer; an n- AlInN cladding layer formed on the first nitride semiconductor layer; an n-InGaN layer formed on the n- AlInN cladding layer; an active layer formed on the n-InGaN layer; a p-InGaN layer formed on the active layer; a p- AlInN cladding layer formed on the p-InGaN layer; and a second nitride semiconductor layer formed on the p- AlInN cladding layer.

Full Text

FORM-2 THE PATENTS ACT, 1970 (39 of 1970) & THE PATENTS RULES, 2003 Provisional /Complete specification [See Section 10 and rule 13] 1 Title of the Invention. "NITRIDE SEMICONDCTOR LIGHT EMITTING DEVICE AND FABRICATION METHOD THEREOF" 2 Applicant (s) Applicant LG INNOTEK CO., LTD Nationality Republic of Korea Address 14th Fl., Hansol Bldg., 736-1, Yoksam-dong, Kangnam-gu, Seoul 135-983, Republic of Korea. The following specification particularly describes the invention and the manner in which it is to be performed. 1 [DESCRIPTION] [Invention Title] NITRIDE SEMICONDCTOR LIGHT EMITTING DEVICE AND FABRICATION METHOD THEREOF [Technical Field] The present invention relates to a nitride semiconductor light-emitting device and fabrication method thereof. [Background Art] Generally, GaN-based nitride semiconductors find its application fields in electronic devices (i.e., high-speed switching and high output devices) such as optical devices of blue/green LED (Light Emitting Diode), MESFET (Metal Semiconductor Field Effect Transistor) and HEMT (High Electron Mobility Transistors). The GaN based nitride semiconductor light emitting device is grown on a sapphire substrate or a SiC substrate. Then, an AlyGai-yN polycrystalline thin film is grown on the sapphire substrate or the SiC substrate as a buffer layer at a low growth temperature. Then, an undoped GaN layer, a Si-doped n-GaN layer, or a mixture of the above two structures is grown on the buffer layer at a high temperature to form an n-GaN layer. Also, a Mg-doped p-GaN layer is formed at upper layer to manufacture a nitride semiconductor light emitting device. An emission layer (a multiple quantum well structure activation layer) is interposed between the n-GaN layer and the p-GaN layer. A related art p-GaN layer is formed by doping Mg atoms while growing crystal. It is required that Mg atoms implanted as a doping source during crystalline growth be substituted by Ga location and thus serve as a p-GaN layer. The Mg atoms are combined with a hydrogen gas dissolved in a carrier gas and a source to form a Mg-H complex in a GaN crystalline layer, resulting in a high resistant material of about 10M?. 2 Accordingly, after a pn junction light-emitting device is formed, there is an need for a subsequent activation process for cutting the Mg-H complex and substituting the Mg atoms at the Ga location. However, in the light-emitting device, the amount of carriers contributing to light emission in the activation process is about 1017 /cm3, which is very lower than the Mg atomic concentration of 1019/cm3 or higher. Accordingly, there is a disadvantage in that it is very difficult to form a resistive contact. Furthermore, the Mg atoms remaining within the p-GaN nitride semiconductor without being activated as carriers serve as the center at which light emitted from the interface with the active layer is trapped, abruptly decreasing the optical output. In order to improve this problem, a method in which contact resistance is lowered to increase current injection efficiency using a very thin transparent resistive metal material has been employed. However, the thin transparent resistive metal used to decrease the contact resistance is about 75 to 80% in optical transmittance. The remaining optical transmittance serves as loss. More particularly, there is a limit to reducing an operating voltage due to high contact resistance. [Disclosure! [Technical Problem] An object of the present invention is to provide a nitride semiconductor light-emitting device and fabrication method thereof, wherein the crystallinity of an active layer constituting the nitride semiconductor light-emitting device can be improved and the optical output and reliability can be improved. [Technical Solution] In order to accomplish the above object, a first embodiment of a nitride semiconductor light-emitting device according to the present invention comprises a first nitride semiconductor layer; an active layer formed on 3 the first, nitride semiconductor layer; a second nitride semiconductor layer formed on the active layer; and a third nitride semiconductor layer having Alln, which is formed on the second nitride semiconductor layer. Furthermore, in order to accomplish the above object, a second embodiment of a nitride semiconductor light-emitting device according to the present invention comprises a substrate; a buffer layer forming on the substrate; a first GaN based layer into which In is doped, the first GaN based layer being formed on the buffer layer; a second GaN based layer into which Si and In are doped, the second GaN based layer being formed on the first GaN based layer; an InxGai-xN layer formed on the second GaN based layer; an active layer formed on the InxGai-xN layer; a p-GaN based layer formed on the active layer; and an n-AlInN layer or a p-AllnN layer formed on the p-GaN based layer. Furthermore, in order to accomplish the above object, a third embodiment of a nitride semiconductor light-emitting device according to the present invention comprises a first nitride semiconductor layer; an n-AllnN cladding layer formed on the first nitride semiconductor layer; an n-InGaN layer formed on the n-AlInN cladding layer; an active layer formed on the n-InGaN layer; a p-InGaN layer formed on the active layer; a p-AllnN cladding layer formed on the p-InGaN layer; and a second nitride semiconductor layer formed on the p-AllnN cladding layer. Furthermore, in order to accomplish the above object, a fourth embodiment of a nitride semiconductor light-emitting device according to the present invention comprises a first nitride semiconductor layer; an n-AllnN cladding layer formed on the first nitride semiconductor layer; an active layer formed on the n-AIInN cladding layer; a p-AllnN cladding layer formed on the active layer; and a second nitride semiconductor layer formed on the p-AllnN cladding layer. Furthermore, in order to accomplish the above object, a fifth embodiment 4 of a nitride semiconductor light-emitting device according to the present invention comprises a first nitride semiconductor layer; an active layer formed on the first nitride semiconductor layer; a p-InGaN layer formed on the active layer; a p-AllnN cladding layer formed on the p-InGaN layer; and a second nitride semiconductor layer formed on the p-AllnN cladding layer. Furthermore, in order to accomplish the above object, a first embodiment of a method of fabricating a nitride semiconductor light-emitting device according to the present invention comprises; forming a buffer layer on a substrate; forming a GaN based layer on the buffer layer; forming a first electrode layer on the GaN based layer; forming an InxGai-xN layer on the first electrode layer; forming an active layer on the InxGai-xN layer; forming a p-GaN based layer on the active layer; and forming an n-AllnN layer or a p-AIInN layer on the p-GaN based layer. Furthermore, in order to accomplish the above object, a second embodiment of a method, of fabricating a nitride semiconductor light-emitting device according to the present invention comprises: forming a buffer layer on a substrate; forming an In-doped GaN based layer into which indium (In) is doped on the' buffer layer; forming a first electrode layer on the In-doped GaN based layer; forming an n-AllnN cladding layer on the first electrode layer; forming an active layer on the n-AllnN cladding layer; forming a p-AIInN cladding layer on the active layer; forming a p-GaN based layer on the p-AIInN cladding layer; and forming a second electrode layer on the p-GaN based layer. Furthermore, in order to accomplish the above object, a third embodiment of a method of fabricating a nitride semiconductor light-emitting device according to the present invention comprises: forming a buffer layer on a substrate; forming an In-doped GaN based layer into which indium (In) is doped on the buffer layer; forming a first electrode layer on the In-doped 5 GaN based layer; forming an active layer that emits light on the first electrode layer; forming a p-lnGaN layer on the active layer; forming a p-AllnN cladding layer on the p-InGaN layer; forming a p-GaN based layer on the p-AIInN cladding layer; and forming a second electrode layer on the p-GaN based layer. [Advantageous Effects] According to the present invention, the crystallinity of an active layer constituting a nitride semiconductor light-emitting device can be improved and the optical output and reliability can be improved. [Description of Drawings] FIG. 1 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a first embodiment of the present invention. FIG. 2 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a second embodiment of the present invention. FIG. 3 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a third embodiment of the present invention. FIG. 4 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a fourth embodiment of the present invention. FIG. 5 is a view schematically showing the stack structure of a nitride semiconductor fight-emitting device according to a fifth embodiment of the present invention. FIG. 6 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a sixth embodiment of the present invention. FIG. 7 is a view schematically showing the stack structure of a nitride 6 semiconductor light-emitting device according to a ninth embodiment of the present invention. FIG. 10 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a tenth embodiment of the present invention. FIG. 11 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to an eleventh embodiment of the present invention. [Mode for Invention] The present invention will be described in detail below in connection with embodiments with reference to the accompanying drawings. FIG. 1 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a first embodiment of the present invention. A nitride semiconductor light-emitting device 1 according to the present invention includes a buffer layer 4 formed on a substrate 2, as shown in FIG. 1. In this case, the buffer layer 4 can have one of an AlInN/GaN stack structure, an InGaN/GaN superlattice structure, an InxGa1_xN/GaN stack structure, an AlxInyGaMx+v)N/InxGa[.xN/GaN stack structure (0 An In-doped GaN layer 6 into which indium is doped is then formed on the buffer layer 4. A n-type first electrode layer is fo rmed on the In-doped GaN layer 6. In this case, a Si-In co-doped GaN layer 8 into which silicon and indium are doped at the same time can be adopted as the n-type first electrode layer. An InxGai-xN layer 10 having a low content of indium is also formed on the Si-In co-doped GaN layer S. An active layer 12 for emitting light is formed on the InxGai-xN layer 10. The active layer 12 can have a single quantum well structure or a multi quantum well structure formed as an InGaN well layer/InGaN barrier layer. An example of the stack structure will be described in more detail with reference to FIG. 3 later on. A p-GaN layer 14 is then formed on the active layer 12. At this time, the p-GaN layer 14 may be formed so that it may be doped with magnesium. A n-type second electrode layer is then formed on the p-GaN layer 14. In this case, an n-AllnN layer 16 may be adopted as the n-type second electrode layer. At this time, the n-AllnN layer 16 may be formed so that it may be doped with silicon. In the nitride semiconductor light-emitting device according to the present invention, the Si-In_ co-doped GaN layer 8 (i.e., the first electrode layer) and the n-AllnN layer 16 (i.e., the second electrode layer) are all formed using n-type nitride and the p-GaN layer 14 is formed between the Si-In co-doped GaN layer 8 and the n-AllnN layer 16. In view of the above, it can be considered that the nitride semiconductor light-emitting device according to the present invention has an n/p/n junction light-emitting device structure unlike the related art p/n junction light-emitting device. As described above, the present invention can provide a scheme in which a tow carrier concentration generating due to the structure of the related art p/n junction light-emitting device and low Mg doping efficiency of the p-GaN nitride semiconductor itself, and a current crowding problem depending on an increase of contact resistance accordingly can be 8 overcome. More particularly, by forming the n-AllnN nitride semiconductor on an upper side, transparent conductive oxide such as ITO having optical transmittance of 95% higher can be used as a transparent electrode. That is, the transparent electrode for applying a bias voltage to an n-AllnN layer may include a transparent resistive material or transparent conductive .oxide, which can maximize current spreading so as to maximize the optical output and has a good optical transmittance. ITO, ZnO, RuOx, IrOx, NiO, or Au alloy metal including Ni may be used as such a material. It is thus possible to implement the optical output of 50% or higher compared to the related art p/n junction through'the use of the transparent electrode. Furthermore, the present invention can lower an operating voltage owing to low contact resistance and can improve the reliability of devices accordingly. More particularly, a high output light-emitting device using a flip chip method necessarily requires a low operating voltage when being applied with the current of a targe area 300mA or higher. If contact resistance of the light-emitting device itself is relatively high so as to apply the same current, the operating voltage is increased. Accordingly, heat of 100"C or higher is generated in the light-emitting device itself. Heat generated internally has a decisive influence on the reliability. According to the n/p/n junction light-emitting device in accordance with the present invention, when the same current is applied due to low contact resistance, the device can be driven a relatively low operating voltage and heat generating within the device is low. Therefore, a light-emitting device with high reliability can be provided. Meanwhile, FIG. 2 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a second 9 embodiment of the present invention. The stack structure of the nitride semiconductor light-emitting device 21 according to a second embodiment of the present invention shows a case where a super grading n-InxGai.xN layer 24 whose energy bandgap is controlled by sequentially changing the indium composition is further formed On the n-AlInN layer 16, when compared with the nitride semiconductor light-emitting device 1 shown in FIG. 1. At this time, the super grading n-InxGa1-xN layer 24 can be formed to have the composition of 0 A nitride semiconductor light-emitting device 21 having this stack structure can be considered as an n/n/p/n junction light-emitting device. Further, in the nitride semiconductor light-emitting device 21 having this stack structure, a transparent electrode for applying a bias voltage can be formed in the super grading n-InxGa1-xN layer 24. Furthermore, though not shown in the drawing, an InGaN/AlInGaN superlattice structure layer or an InGaN/InGaN superlattice structure layer can be formed on the n-AllnN layer 16 instead of the super grading n-InxGa1_xN layer 24. In this case, the InGaN/AlInGaN superlattice structure layer or the InGaN/InGaN superlattice structure layer may be doped with silicon. The structure of an active layer adopted in a nitride semiconductor light-emitting device 31 according to the present invention will be described in more detail with reference to FIG. 3. FIG. 3 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a third embodiment of the present invention. The layers (the same reference numerals given), which have been described with reference to FIG. 1, of the stack structure shown in FIG. 3, will not be described. In the nitride semiconductor light-emitting device 31 according to a third embodiment of the present invention, a low-mole InxGai-xN layer 10 having a low content of indium that controls the strain of the active layer is formed in order to increase internal quantum efficiency, as shown in FIG. 3. Furthermore, in order to improve the optica! output and reverse leakage current due to indium fluctuation, SiNx cluster layers 33, 35, which are controlled in atomic scale form, are further formed on top and bottom surfaces of the low-mole InxGai-xN layer 10, respectively. Furthermore, the active layer that emits light can have a single quantum well structure or a multiple quantum well structure formed of an InyGai-yN well layer/InzGai-zN barrier layer. FIG. 3 shows an example of the light-emitting device having a multiple quantum well structure in which SiNx cluster layers 39, 45 are further provided between InyGai-yN well layers 37, 43 and InzGai-zN barrier layers 41, 47 as the active layers. In this case, in order to improve light-emitting efficiency of the active layer, the composition ratio can be controlled to InyGai-yN well layer (0 11 Furthermore, after the last layer of the active layer, which has a single quantum well structure or a multiple quantum well structure, is grown, a SiNx cluster layer 140 is grown to a thickness of atomic scale, so that internal diffusion of the active layer within Mg atoms of the p-GaN layer 100 can be prohibited. Meanwhile. FIG. 4 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a fourth embodiment of the present invention. The layers (the same reference numerals given), which have been described with reference io FIG. 1, of the stack structure shown in FIG. 4, will not be described. A nitride semiconductor light-emitting device 51 according to a fourth embodiment of the present invention further includes a super grading n-InxGa1-xN layer 52 whose energy bandgap is controlled by sequentially changing the indium composition is further formed on the p-GaN layer 14. Furthermore, FIG. 4 shows a case where an n-AUnN layer 54 is further formed on the super grading n-In.xGa1-xN layer 52. The nitride semiconductor light-emittins device 51 having; this stack structure can be interpreted as an n/n/p/n junction light-emitting device. Further, in the nitride semiconductor light-emitting device 53 having this stack structure, a transparent electrode for applying a bias voltage may be formed in the n-AIInN layer 54. Meanwhile, although FIG. 4 shows a case where the super grading n-InxGa1-xN layer 52 is formed on the p-GaN layer 15, an InGaN/AlInGaN supperlattice structure layer or an InGaN/InGaN superlattice structure may be formed on the p-GaN layer 15 instead of the super grading n-InxGa1-xN layer 52. Furthermore, FIG. 5 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a fifth embodiment of the present invention. The layers (the same reference numerals numerals given), which have been described with reference to FIG. 1, of the stack structure shown in FIG. 5, will not be described. A nitride semiconductor light-emitting device 61 according to a fifth embodiment of the present invention is characterized in that a p-AllnN layer 66 is formed on the p~GaN layer 16. In this case, the p-AllnN layer 66 may be doped with magnesium. The nitride semiconductor light-emitting device 61 having this stack structure can be interpreted as a p/n junction light-emitting device, but can provide light-emitting efficiency similar to other embodiments by way of a physical characteristic of the p-AllnN layer 66. Further, in the nitride semiconductor light-emitting device 61 having this stack structure, a transparent electrode for applying a bias voltage may be formed in the p-AllnN layer 66. Further, FIG. 6 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a sixth embodiment of the present invention. The stack structure of a nitride semiconductor light-emitting device 71 according to a sixth embodiment of the present invention shows a case where a super grading n~InxGai-xN layer 74 whose energy bandgap is controlled by sequentially changing the indium composition is further formed on the p-AIInN layer 66, when compared with the nitride semiconductor light-emitting device 61 shown in FIG. 5. At this time, the super grading n~InxGai-xN layer 74 may be formed to have the composition of 0 A nitride semiconductor light-emitting device 71 having this stack structure can be considered as an n/p/p/n junction light-emitting device. Further, in the nitride semiconductor light-emitting device 71 having this stack structure, a transparent electrode for applying a. bias voltage may 13 be formed in the super grading n-InxGa1-xN layer 74. Furthermore, though not shown in the drawing, an InGaN/AlInGaN superlattice structure layer or an InGaN/InGaN superlattice structure layer may be formed on the n-AIInN layer 66 instead of the super grading n-InxGa,.xN layer 74. In this case, the InGaN/AlInGaN superlattice structure layer or the InGaN/InGaN superlattice structure layer may be doped with silicon. Meanwhile,. FIG. 7 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a seventh embodiment of the present invention. A nitride semiconductor light-emitting device 81 according to the present invention includes a buffer layer 84 formed on the substrate 82, as shown in FIG. 7. In this case, the buffer layer 84 may have an AlInN/GaN stack structure, an InGaN/GaN superlattice structure, an InxGa1-xN/GaN stack structure or the stack structure of ALJnyGa1-x+y)N/InxGa]_xN/GaN. Further, an In-doped GaN layer 86 into which indium is doped is formed on the buffer layer 84. A n-type first electrode layer is formed on the In-doped GaN layer 86. In this case, a Si-In co-doped GaN layer S8 into which silicon and indium are doped at the same time can be adopted as the n-type first electrode layer. Furthermore, an n-AlInN cladding layer 90 is formed on the Si-In co-doped GaN layer 88. An n-InGaN layer 92 is formed on the n-AlInN cladding layer 90. An active layer 94 that emits light is also formed on the n-InGaN layer 92. The active layer 94 may have a single quantum well structure or a multiple quantum well structure. An example of the stack structure constituting the active layer 94 will be described in more detail later on with reference io FIG. 9. In addition, according to the active layer 94 in accordance with the present invention, there is an advantage in that sufficient optical efficiency can be accomplished even the active layer 94 has a single quantum well structure. Thereafter, a p-lnGaN layer 96 is formed on the active layer 94. A p-AllnN cladding layer 98 is formed on the p-InGaN layer 96. Furthermore, a p-GaN layer 100 is formed on the p-AllnN cladding layer 98. At this time, the p-GaN layer 100 may be doped with magnesium (Mg). In addition, an n-type second electrode layer is formed on the p-GaN layer 100. In this case, a super grading n-InxGai-xN layer 102 whose energy bandgap is controlled by sequentially changing the indium composition can be adopted as the n-type second electrode layer. At this time, the composition of the super grading n-InxGai-xN layer 102 can be controlled to 0 As described above, in the nitride semiconductor light-emitting device according to the present invention, both the first electrode layer 88 and the second electrode layer 102 are formed using an n-type nitride semiconductor and the p-GaN layer 100 is formed therebetween. Therefore, in view of the above structure, it can be considered that the nitride semiconductor light-emitting device of the present invention has an npn junction light-emitting device structure unlike the related art pn junction light-emitting device. Furthermore, the n-type nitride semiconductor (e.g., the super grading n-InxGai-xN layer 102), which is used as the second electrode layer, has resistance lower than that of an existing p-GaN contact layer. Thus, contact resistance can be reduced and current implantation can be maximized. In addition, a transparent electrode for applying a bias voltage to the second electrode layer can include a transparent resistive material or transparent conductive oxide, which can maximize current dispersing so as to maximize the optical output and have a good optical 15 transmittance. ITO, ZnO, RuOx, IrOx, NiO, or Au alloy metal including Ni may be used as such a material. In this case, though not shown in the drawing, the second electrode layer may have an InGaN/AlInGaN superlattice structure layer or an InGaN/InGaN supper lattice structure layer. Further, the InGaN/AIJnGaN superlattice structure layer or the InGaN/InGaN superlattice structure layer may be doped with silicon. Furthermore, though not shown in the drawing, an n-AIInN layer may be used as the second electrode layer. According to the nitride semiconductor light-emitting device SI constructed above in accordance with the present invention, the n-AIInN cladding layer 90 and the p-AlInN cladding layer 98 are inserted lower/upper side to the active layers 94, respectively. Therefore, internal quantum efficiency can be improved by prohibiting carrier implantation efficiency within the active layer 94 and current overflow. Further, FIG. 8 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to an eighth embodiment of the present invention. The layers (the same reference numerals given), which have been described with reference to FIG. 7, of the stack structure shown in FIG. 8, will not be described. The nitride semiconductor light-emitting device 111 according to eighth embodiment of the present invention is different from the nitride semiconductor lisht-emitting device 81 shown in FIG. 7 according to the seventh embodiment in that an InxGa1-xN layer 114 having a low content of indium. That is, according to the nitride semiconductor light-emitting device 111 in accordance with an eighth embodiment of the present invention, the InxGal-xN layer 114 having a low content of indium is further formed between the n-InGaN layer 92 and the active layer 94. The reason is that in order to increase internal quantum efficiency, the InxGai-xN layer 114 having a low content of indium is further formed so that it can control the strain of the active layer 94. - - The structure of an active layer adopted in a nitride semiconductor light-emitting device 121 according to the present invention will be described in more detail with reference to FIG. 9. FIG. 9 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to an ninth embodiment of the present invention. The layers (the same reference numerals given), which have been described with reference to FIG. 7, of the stack structure shown in FIG. 9, will not be described. The nitride semiconductor light-emitting device 121 according to a ninth embodiment of the present invention includes a low-mole InxGai-xN layer 122 having a low content of indium, which controls the strain of the active layer, in order to increase internal quantum efficiency, as shown in FIG. 9. Furthermore, in order to improve the optical output and reverse leakage current due to indium fluctuation, SiNx cluster layers 132, 134, which are controlled in atomic scale form, are further formed on top and bottom surfaces of the low-mole InxGai-xN layer 122. Furthermore, the active layer that emits light may have a single quantum well structure or a multiple quantum well structure formed using an InyGai-yN well layer/InzGai-zN barrier layer. FIG. 9 shows an example of the light-emitting device having a multiple quantum well structure in which SiNx cluster layers 136, 138 are further provided between InyGai-yN well layers 124, 128 and InzGai-2N barrier layers 126, 130 as the active layers. In this case, in order to improve emission efficiency of the active layer, the composition ratio may be controled to InyGai-yN well layer(0 17 low-mole InxGai-xN layer 122 having a low content of indium, the content of indium doped into the InyGai-yN well layers 124, 128, the content of indium doped into the InzGai-zN barrier layers 126, 130 and the content of indium doped into the low-mole InsGai-xN layer 122 may be controlled to have 0 Furthermore, though not shown in the drawing, a GaN cap layer that controls the amount of indium fluctuation in the InyGai-yN well layer may be further formed between the InyGai-yN well layer and the In2Gai-zN barrier layer, which form the active layers. At this time, the content of indium of each of the well layer and the barrier layer that emit light may be constructed using InyGai->-N(0 Meanwhile, FIG. 10 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to a tenth embodiment of the present invention. The layers (the same reference numerals given), which have been described with reference to FIG. 7, of the stack structure shown in FIG. 10, will not be described. A nitride semiconductor light-emitting device 141 according to a tenth embodiment of the present invention includes an active layer 94 formed on an n-AllnN cladding layer 90 and a p-AIInN cladding layer 98 formed on the active layer 94. That is, the nitride semiconductor light-emitting device 141 according.to a tenth embodiment of the present invention has a modified stack structure in which the n-InGaN layer 92 and the p-InGaN layer 96 are not formed when compared with the nitride semiconductor light-emitting 18 device 81 according to a seventh embodiment shown in FIG. 7. Further, FIG. 11 is a view schematically showing the stack structure of a nitride semiconductor light-emitting device according to an eleventh embodiment of the present invention. The layers (the same reference numerals given), which have been described with reference to FIG. 7, of the stack structure shown in FIG. 11, will not be described. A nitride semiconductor light-emitting device 151 according to an eleventh embodiment of the present invention includes an active layer 94 formed on a Si-In co-doped GaN layer 88 (i.e., a first electrode layer), and a p-InGaN layer 96 and a p-AllnN cladding layer 98 both of which are formed on the active layer 94. That is, the nitride semiconductor light-emitting device 151 according to a eleventh embodiment of the present invention has a modified stack structure in which the n-AllnN cladding layer 90 and the n-InGaN layer 92 are not formed when compared with the nitride semiconductor light-emitting device 81 according to a seventh embodiment shown in FIG. 7. [Industrial Applicability] According to a nitride semiconductor light-emitting device and fabricating method thereof in accordance with the present invention, there are advantages in that the crystallinity of an active layer constituting a nitride semiconductor light-emitting device can be improved and the optical output and reliability can be improved. 19 Amended claims We Claim [Claim1] A nitride semiconductor light-emitting device, comprising: a first nitride semiconductor layer, having a n-type nitride semiconductor layer; an active layer formed on the first nitride semiconductor layer; a p-type second nitride semiconductor layer formed on the active layer; and a third nitride semiconductor layer having n-Alln, which is -formed on the second nitride semiconductor layer; the first, second and third nitride semiconductor layers form an n/p/n junction allowing the light emitting device to be driven at relatively low operating voltage thus providing high reliability. [Claim 2] The nitride semiconductor light-emitting device as claimed in claim 1, wherein a substrate and a buffer layer formed on the substrate are further formed under the first nitride semiconductor layer. [Claim3] The nitride semiconductor light-emitting device as claimed in claim 1, wherein the first nitride semiconductor layer comprises: a GaN based layer into which In is doped or not doped; a first electrode layer formed on the GaN based layer; and an InxGal-xN layer formed on the first electrode layer, wherein the first electrode layer is the n-type nitride semiconductor layer. [Claim 4] The nitride semiconductor light-emitting device as claimed in claim 2, wherein the buffer layer has one of an AlInN/GaN stack structure, an InGaN/GaN supperlattice structure, an InxGal-xN/GaN stack structure and a stack structure of an AlxInyGal- (x+y)N/InxGal-xN/GaN. [Claim 5] The nitride semiconductor light-emitting device as claimed in claim 3, wherein the first electrode layer is a GaN based layer into which silicon and indium are doped at the same time. [Claim 6] The nitride semiconductor light-emitting device as claimed in claim 1, wherein the second nitride semiconductor layer is doped with magnesium. [Claim 7] The nitride semiconductor light-emitting device as claimed in claim 1, wherein the third nitride semiconductor layer is doped with silicon. [Claim8] The nitride semiconductor light-emitting device as claimed in claim 1, further comprising a transparent electrode formed on the third nitride semiconductor layer. [Claim 9] The nitride semiconductor light-emitting device as claimed in claim 8. wherein the transparent electrode is formed using transparent conductive oxide or a transparent resistive material. [Claim 10] The nitride semiconductor light-emitting device as claimed in claim 9, wherein the transparent conductive oxide is formed using one of ITO, ZnO, IrOx, RuOx and NiO materials. [Claim 11] The nitride semiconductor light-emitting device as claimed in claim 9, wherein the transparent resistive material is formed using an Au alloy layer including Ni metal. [Claim 12] A method of fabricating a nitride semiconductor light-emitting device, the method comprising: forming a buffer layer on a substrate; forming a GaN based layer on the buffer layer; forming a first electrode layer being n-type nitride semiconductor layer on the GaN based layer; forming an InxGal-xN layer on the first electrode layer; forming an active layer on the InxGal-xN layer; forming a p-GaN based layer on the active layer; and forming an n-AUnN layer on the p-GaN based layer. [Claim 13] The method as claimed in claim 12, further comprising the step of forming an n-InxGal-xN layer of a super grading structure whose content of indium is sequentially changed or an InGaN/AlInGaN supperlattice structure layer or an InGaN/InGaN supperlattice structure layer on the p-GaN based layer. [Claim 14] The method as claimed in claim 12, wherein the buffer layer has one of an AlInN/GaN stack structure, an InGaN/GaN supperlattice structure, an InxGal-xN/GaN stack structure and a stack structure of an AlxInyGal-(x+y)N/InxGal-xN/GaN. [Claim 15] The method as claimed in claim 12, wherein the first electrode layer is a GaN based layer into which silicon and indium are doped at the same time.. [Claim 16] The method as claimed in claim 12, further comprising the step of forming a first SiNx cluster layer and a second SiNx cluster layer, respectively, prior to and after the step of forming the }nxGal-xN layer. [Claim 17] The method as claimed in claim 12, further comprising the step of forming a S.iNx cluster layer between the active layer and the p-GaN based layer. [Claim 18] The method as claimed in claim 12, further comprising the step of forming an n-InxGal-xN layer of a super grading structure whose content of indium is sequentially changed or an InGaN/AlInGaN supperlattice structure layer or an InGaN/InGaN supperlattice structure layer on the n-AlInN layer or the p-AUnN layer. [Claim 19] The method as claimed in claim 12, further comprising the step of forming a transparent electrode on the n-AlInN layer or the p-AUnN layer. [Claim 20] The method as claimed in claim 18, further comprising the step of forming a transparent electrode on the super grading structure or the supperlattice structure layer.

Documents:

381-MUMNP-2007-ABSTRACT(GRANTED)-(14-5-2012).pdf

381-mumnp-2007-abstract.doc

381-mumnp-2007-abstract.pdf

381-MUMNP-2007-CANCELLED PAGES(21-2-2012).pdf

381-MUMNP-2007-CLAIMS(AMENDED)-(12-12-2011).pdf

381-MUMNP-2007-CLAIMS(AMENDED)-(21-2-2012).pdf

381-MUMNP-2007-CLAIMS(GRANTED)-(14-5-2012).pdf

381-MUMNP-2007-CLAIMS(MARKED COPY)-(21-2-2012).pdf

381-mumnp-2007-claims.doc

381-mumnp-2007-claims.pdf

381-MUMNP-2007-CORRESPONDENCE(16-3-2012).pdf

381-MUMNP-2007-CORRESPONDENCE(21-8-2008).pdf

381-MUMNP-2007-CORRESPONDENCE(29-10-2010).pdf

381-MUMNP-2007-CORRESPONDENCE(IPO)-(14-5-2012).pdf

381-mumnp-2007-correspondence-received.pdf

381-mumnp-2007-descripiton (complete).pdf

381-MUMNP-2007-DESCRIPTION(GRANTED)-(14-5-2012).pdf

381-MUMNP-2007-DRAWING(GRANTED)-(14-5-2012).pdf

381-mumnp-2007-drawings.pdf

381-MUMNP-2007-FORM 13(16-3-2012).pdf

381-MUMNP-2007-FORM 13(9-2-2012).pdf

381-MUMNP-2007-FORM 18(21-8-2008).pdf

381-MUMNP-2007-FORM 2(GRANTED)-(14-5-2012).pdf

381-MUMNP-2007-FORM 2(TITLE PAGE)-(14-3-2007).pdf

381-MUMNP-2007-FORM 2(TITLE PAGE)-(GRANTED)-(14-5-2012).pdf

381-MUMNP-2007-FORM 3(12-12-2011).pdf

381-MUMNP-2007-FORM 3(21-2-2012).pdf

381-mumnp-2007-form-1.pdf

381-mumnp-2007-form-2.pdf

381-mumnp-2007-form-3.pdf

381-mumnp-2007-form-5.pdf

381-MUMNP-2007-GENERAL POWER OF ATTORNEY(21-2-2012).pdf

381-MUMNP-2007-PETITION UNDER RULE 137(9-2-2012).pdf

381-MUMNP-2007-REPLY TO EXAMINATION REPORT(12-12-2011).pdf

381-MUMNP-2007-REPLY TO HEARING(21-2-2012).pdf

381-MUMNP-2007-SPECIFICATION(AMENDED)(16-3-2012).pdf

381-MUMNP-2007-SPECIFICATION(AMENDED)-(12-12-2011)-.pdf

381-MUMNP-2007-SPECIFICATION(AMENDED)-(12-12-2011).pdf

381-MUMNP-2007-SPECIFICATION(MARKED COPY)-(12-12-2011).pdf

381-MUMNP-2007-SPECIFICATION(MARKED COPY)-(16-3-2012).pdf

381-MUMNP-2007-US DOCUMENT(12-12-2011).tif

381-mumnp-2007-wo international publication report(14-3-2007).pdf

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