WO2013066088A1 - Transparent thin film, light-emitting device comprising same and method for manufacturing same - Google Patents

Abstract

The present invention relates to a transparent thin film, a light-emitting device comprising the same and to a method for manufacturing the same. A light-emitting device formed by a nitride semiconductor having a composition of Al_xIn_yGa_(1-x-y)N, (0≤x≤1, 0≤y≤1, 0≤x+y≤1) according to the present invention comprises: a substrate; a buffer layer formed on the substrate; a first electrode contact layer formed on the buffer layer; a first clad layer formed on the first electrode contact layer; an active layer formed on the first clad layer; a second clad layer formed on the active layer; a second electrode contact layer formed on the second clad layer; a transparent electrode which is formed on the second electrode contact layer and which has a multi-layer structure in which a plurality of ZnO thin films are stacked, wherein at least a portion of the ZnO thin films is doped with at least one n-type impurity selected from a group consisting of III family elements of B, Al, Ga and In and F, Cl and H, or doped with at least one p-type impurity selected from a group consisting of V family elements of N, P, As and Sb and Li, Na and C, or doped with both said n-type impurity and said p-type impurity; a first electrode pad formed on a portion of an upper surface of the first electrode contact layer; and a second electrode pad formed on a portion of an upper surface of the transparent electrode.

Description

Transparent thin film, light emitting device comprising same and manufacturing method thereof

The present invention relates to a transparent thin film, a light emitting device including the same, and a method for manufacturing the same, and more particularly, to a transparent thin film including a plurality of ZnO thin films, a light emitting device including the same, and a method for manufacturing the same. N-type impurities are doped, p-type impurities such as As are doped, or n-type impurities such as Ga and p-type impurities such as As are simultaneously doped.

Materials of light emitting devices, particularly nitride semiconductors, have been spotlighted as core materials of light emitting devices such as light emitting diodes (LEDs) or laser diodes (LDs) with excellent physical and chemical properties. The nitride semiconductor is usually made of a GaN-based material having a composition formula of Al _x In _y Ga _(1-xy) N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1). 1 is a cross-sectional view schematically showing a laminated structure of a light emitting device using a conventional AlInGaN-based nitride semiconductor. In manufacturing a light emitting device using an AlInGaN-based nitride semiconductor, the n-type nitride semiconductor layer 105 and the n-type nitride cladding layer 107 functioning as the substrate 101, the buffer layer 103, and the first electrode contact layer. ), The active layer 109, the p-type nitride cladding layer 111, the p-type nitride semiconductor layer 113, and the n / p-type second electrode contact layer 115 are laminated and grown. Subsequently, during the chip manufacturing process, a transparent electrode layer, particularly an ITO transparent electrode layer 117, is formed on the n / p-type second electrode contact layer 115, and finally a p-type for wire bonding. The electrode pad 121 and the n-type electrode pad 119 are formed as shown in FIG.

As the substrate 101, a sapphire substrate having a hexagonal crystal structure is mainly used. The buffer layer 103 may be grown on the substrate 101 to minimize crystal defects caused by the difference in lattice constant and thermal expansion coefficient of the sapphire substrate 101 and the n-type nitride semiconductor layer 105. The buffer layer 103 may be formed of GaN-based or AlN-based nitride having a thickness of 50 nm or less having an amorphous crystal phase at a low temperature of 500 ° C to 600 ° C. In addition, an undoped GaN layer may be further formed on the buffer layer 103. Subsequently, n- doped with silicon at a doping concentration of 1 to 5 × 10 ¹⁸ / cm ³ to form electrons as carriers contributing to electrical conductivity within a growth temperature of 1000 ° C. to 1100 ° C. The type nitride semiconductor layer 105 is grown. The n-type nitride semiconductor layer 105 is used as the first electrode contact layer in electrical contact with the n-type electrode pad 119. After the n-type nitride cladding layer 107 is formed on the n-type nitride semiconductor layer 105, the growth temperature is lowered to 700 ° C. to 800 ° C. to form an active layer having a single or multiple quantum well structure of InGaN / GaN and InGaN / InGaN. 109 is formed. Thereafter, the p-type nitride cladding layer 111, the p-type nitride semiconductor layer 113, and the n / p-type second electrode contact layer 115 are formed on the active layer 109.

In the process of forming the n / p-type second electrode contact layer 115, n-type Si, p-type Cp ₂ Mg or DMZn are doped as impurities. When DMZn is used as the p-type impurity, the Zn atoms are positioned at the 'deep energy level' as the acceptor in the n / p-type second electrode contact layer 115 to form holes as carriers. The activation energy is so high that when the bias is applied, the carrier hole concentration is limited to ˜10 ¹⁷ / cm ³ . Therefore, as a p-type impurity for growing the n / p-type second electrode contact layer 115, relatively low activation energy Cp ₂ Mg is used as the doping source. When the second electrode contact layer 115 is grown using a Cp ₂ Mg as a doping source, NH ₃ source gas used as a nitrogen (N) source in the GaN layer and hydrogen (H) gas separated from the doping source are combined. Mg-H complex is formed and has a high resistance insulator characteristic of ~ 10 ⁶ ohm.cm or more. In order to emit light in the active layer 109 through the recombination process, holes and electrons cannot be used in a doped state of high resistance Mg, and an activation process for breaking the bond of the Mg-H composite ( an activation process is required. The activation process is performed through an annealing process in a temperature condition of 600 ℃ ~ 800 ℃ and N ₂ or N ₂ / O ₂ atmosphere, but the activation efficiency of Mg present in the second electrode contact layer 115 As a result, the second electrode contact layer 115 has a much higher resistance characteristic than the n-type nitride semiconductor layer 105 which is the first electrode contact layer even when the activation process proceeds. After the activation process, the Mg atomic concentration in the second electrode contact layer 115 is about 10 ¹⁹ / cm ³ to 10 ²¹ / cm ³ , but the concentration of the hole which is a carrier contributing to the electrical conductivity is 10 ¹⁷ / cm ³ It is only a degree, and the hall mobility is very low, 10 cm ² / Vsec. In addition, Mg, Mg-H composites, crystal defects, and the like remaining in the second electrode contact layer 115 without being fully activated may trap light emitted from the active layer 109 toward the surface, or a high current When is applied, heat is generated by the resistance characteristics of the second electrode contact layer 115, which is relatively very high, thereby shortening the lifespan of the light emitting device and adversely affecting reliability. In particular, in the case of a large area / high output light emitting device having a size of 1 mm × 1 mm, a high current of 350 mA is applied, which is much higher than the existing 20 mA, so that a junction temperature of 100 ° C. or more occurs at the p- / n- junction surface. This results in a fatal adverse effect on the performance and reliability of the light emitting device and results in a limitation in being used in applications requiring high power. The cause of such heat generation is due to an increase in resistance components due to excess Mg atoms, Mg-H composites, and the like remaining in the second electrode contact layer 115 without being activated as a carrier, and thus the rough surface properties remain unresolved. have. In the conventional p- / n-junction AlInGaN-based nitride semiconductor light emitting device, in the case of the n-type nitride semiconductor layer 105 used as the first electrode contact layer, a flow rate of SiH ₄ or Si ₂ H _{6 which} is a doping source is increased. The doping concentration of silicon increases linearly proportionally and is easily controlled in the range of 1 × 10 ¹⁸ / cm ³ to 9 × 10 ¹⁸ / cm ³ within a critical thickness where crystallinity is guaranteed, but the second In the case of the electrode contact layer 115, the carrier concentration purely contributes to the electron conductivity even if Mg atoms of up to ˜10 ²¹ / cm ³ or more are increased by increasing the flow rate of Cp ₂ Mg as a doping source, and the hole concentration is 1 × 10 ¹⁷ / cm ^Since it is limited in the range of ³ to 8 × 10 ¹⁷ / cm ³ , it has a structure of a p- / n-junction light emitting device having an asymmetrical doping distribution. As described above, the low carrier concentration and the high resistance characteristics of the second electrode contact layer 115 lower the internal quantum efficiency, thereby limiting the implementation of a high efficiency AlInGaN-based nitride semiconductor light emitting device.

In the AlInGaN-based nitride semiconductor light emitting device, due to the high resistance characteristic of the second electrode contact layer 115, it corresponds to a lower portion of the p-type electrode pad 121 in electrical contact with the second electrode contact layer 115. In the InGaN / GaN multiple quantum well layer of the active layer 109, light is emitted through the recombination process of electrons and holes. However, since the p-type electrode pad 121 is connected by Au wire and wire bonding in a package process, the total metal thickness is deposited to be 1 μm or more so that light emitted from the active layer 109 does not pass through the thick metal. Failure to do so can result. In particular, due to the high resistance characteristic of the second electrode contact layer 115, current concentration locally concentrated on the p-type electrode pad 121 without uniform current spreading in the lateral direction. As a result of concentrating, it is difficult to manufacture a high efficiency / high reliability light emitting device due to enormous heat generation. Therefore, the transparent electrode has excellent light transmittance and low contact resistance with the second electrode contact layer 115 to improve the current concentration of the light emitting device and achieve uniform current spreading to the actual light emitting area of the active layer 109. This is necessary. In addition to the technical necessity, the above-described problems of the AlInGaN-based nitride semiconductor are solved by developing and applying a chip process technology to the limitation of the epi-wafer growth technology of the AlInGaN-based nitride semiconductor described above. A solution is proposed. First, an attempt was made to lower the contact resistance by applying a thin Ni / Au alloy on the second electrode contact layer 115. That is, in order to improve current spreading of the second electrode contact layer 115 and increase luminous efficiency, a Ni / Au alloy having a thickness of 20 nm or less was used as the electrode material. Ni / Au alloy, which is used as an electrode material, is a transmissive metal and has a very thin NiO film at the interface when contacted with the second electrode contact layer 115, resulting in low contact resistance, but having a relative light transmittance of 50% to 60%. Low, it is difficult to implement a high efficiency light emitting device. In order to solve this problem, ITO (In ₂ O ₃ : Sn), which has high light transmittance and low contact resistance, is a transparent electrode instead of Ni / Au-transmissive metal, which has been mass-produced since 2002 as a transparent electrode. It is widely applied to backlight units and lighting products for LCD TVs. By using ITO as a transparent electrode, a breakthrough technical advance has been made in which the light output of the light emitting device is improved by about 30%.

The ITO transparent electrode layer 117 can be deposited using equipment for sputtering deposition and e-beam evaporation. The light transmittance is 85% or more and the contact resistance is about 10 ^-5 ohm.cm. And have amorphous or polycrystalline crystallinity with n-type electrical conductivity, and a subsequent heat treatment process is necessarily required for crystallinity recovery after deposition. Due to the polycrystalline crystal structure, current flow in the vertical direction of the active layer 109 at the lower end of the second electrode contact layer 115 is easy, but the current flow in the lateral direction is vertical. Since it is very small compared to the current flow, an improvement is required. In addition, the research and development for improving the performance of the ITO material itself used as a transparent electrode of the light emitting device has been continuously carried out, but the results are incomplete. Recently, rather than research and development on the ITO material itself, the performance of the light emitting device has been improved through the development of the patterning or texturing process technology for the ITO transparent electrode. This is not the case. In addition, the reserve of indium (In) constituting the ITO material is extremely limited, which leads to a problem in that the manufacturing cost is very high.

Therefore, in order to improve performance of AlInGaN-based nitride semiconductor light emitting device and low manufacturing cost, development of a transparent electrode that can replace the existing ITO material is urgently required. In order to meet the needs of smart phones, laptops, PCs, monitors, LCD backlight units, or lighting products, there is an urgent need for high-efficiency light-emitting devices with a light efficiency of 50% or more. The technical limitations on the chip process do not meet this situation. In other words, the epi-wafer growth technology of the AlInGaN-based nitride semiconductor light emitting device has been invested heavily in research and development to improve the internal quantum efficiency by more than 5%. In addition, in order to overcome the technical limitations of the epi-wafer growth technology, efforts have been made to improve the performance of the light emitting device through the development of chip process technology, but no remarkable results are found. In order to overcome such technical difficulties, recently, research and development on ZnO transparent electrodes have been actively conducted as a material to replace ITO materials used as transparent electrodes of AlInGaN-based nitride semiconductor light emitting devices.

ZnO thin film that can be used as a transparent electrode of the light emitting device has an excellent light transmittance of 85% or more, and has the same hexagonal crystal structure as that of the AlInGaN-based nitride semiconductor light emitting device, and has excellent thermal stability, thereby providing large area / high output light emission. It can be effectively applied to the device, and has the advantages of high refractive index and easy adjustment of energy bandgap. In addition, the ZnO thin film has an advantage of easily forming columnar microstructures in the crystal growth direction. In addition, the ZnO thin film uses much richer zinc (Zn) than the indium (In) of the conventional ITO transparent electrode, thereby providing a low cost smooth and stable supply of raw materials. ZnO material, which can replace the conventional ITO transparent electrode, is formed on the p-GaN layer, which is the second electrode contact layer, and has the same hexagonal crystal structure as the p-GaN layer. Since the same can be applied to have the advantage of easily obtaining a good crystallinity. The ZnO material may have a light transmittance of 90% or more due to a high refractive index and a low absorption coefficient, and the escape angle of light emitted from the InGaN / InGaN or InGaN / GaN active layer toward the surface through a change in the formation structure. The transmission efficiency of the light emitting device may be improved by changing the angle).

In the case of a light emitting device, in order to increase the recombination efficiency of electrons and holes in the active layer with high light transmittance in terms of light emission, the contact resistance between the p- / n- electrode is minimized, so that the internal quantum efficiency is maximized even when a low voltage is applied. In order to be practically applied in mass production, the resistance design technology must be satisfied. In order to form a ZnO transparent electrode, a direction of growing amorphous and polycrystalline structures containing additives using sputtering, electron beam deposition, molecular beam epitaxy (MBE), organic chemical vapor deposition (MOCVD), or pulse laser Research and development is progressing toward growing a single crystal structure doped with impurities using a deposition method (PLD). The above-mentioned growth methods can be used to easily obtain a high permeability characteristic through the ZnO material itself or a change in structure, but the results with high electrical conductivity due to low contact resistance have not been obtained to date. The development direction of ZnO transparent electrode is largely developed for nanorod and nanowire shapes to improve light transmittance, and impurities contributing to electrical conductivity in the form of thin film of 5000 의 or less for improving light transmittance and electrical conductivity. It can be classified as the development of n- / p- doped structure with addition or doping. In particular, in the latter development direction, research results on AZO (ZnO: Al), GZO (ZnO: Ga), and IZO (ZnO: In) thin films doped with impurities and impurities to improve electrical conductivity have been reported. Specifically, in the direction of electron development, Sung Jin An, 'Near ultraviolet light emitting diode composed of n-GaN / ZnO coaxial nanoroad heterostructures on a p-GaN layer', Applied Physics Letters 91, 123109 (2007). Xiao-Mei Zhang et al., “Fabrication of a High-Brightness Blue-Light-Emitting Diode Using a ZnO-Nanowire Array Grown on p-GaN Thin Film”, Advanced Materials. Vol.21, pp.2767-2770 (2009) 'papers reported ZnO nanorods and nanowires. However, although the ZnO type can be easily changed, the resistance value contributing to the electrical conductivity is relatively high, and thus the operating voltage of the light emitting device is evaluated to have a very high limit. In the latter direction of development, K. Nakahara, 'Two different features of ZnO: transparent ZnO: Ga electrode for InGaN-LED and homoepitaxial ZnO films for UV-LEDs.' Zinc Oxide Materials and Devices, Proc. In SPIE Vol. 6222, pp61220N (2006), in the paper, GZ0 (ZnO: with n-type electrical conductivity is obtained by doping gallium (Ga) as a doping source during ZnO thin film growth process using molecular beam epitaxy (MBE). Although a light emitting device having a light transmittance of 80% or more was reported using a Ga) / p-GaN layer transparent electrode, conditions for low operating voltages required by various products were not presented. Gary S. Tompa, “Large Area Multi-Wafer MOCVD of Transparent and Conducting ZnO Fils,” Mater. Res. Soc. Symp. Vol.957 (2007), AZO (ZnO: Al) transparent electrode with n-type electrical conductivity by doping aluminum (Al) as doping source during ZnO thin film growth process using organometallic chemical vapor deposition (MOCVD) Although a light emitting device has been reported to have a light transmittance of 10% or more compared to an ITO transparent electrode with a light transmittance of 80% or more, the operating voltage is evaluated to be relatively high.

Liu Zhen, `` A Ga-doped ZnO transparent Conduct Layer for GaN-based LEDs '', Journal of Semiconductor, Vol.31., No.9, 2010, in the paper, uses GaV-doped ZnO transparent devices using MOVPE growth equipment. It was reported that a 23.6% improvement in light output was achieved at 20 mA by growing the electrode layer, but it was reported that a Ga <sub>2</sub> O <sub>3</sub> insulating film was formed to have a high operating voltage. Ken Nakahara, 'Improved External Efficiency InGaN-based Light Emitting Diodes with Transparent Conductive Ga-doped ZnO as p-Electrodes', Japanese Journal of Applied Physics, Vol. 43, No. 2A, pp. L180-182, 2004., Papers At 20mA, it is about 20.8% higher than Ni / Au transparent electrode and operating voltage is 3.5V, but it is lower than ITO transparent electrode in mass production. HY Liu, 'InGaN based Light Emitting Didoes Utilizing Ga-doped ZnO as a Highly Transparent Contact to p-GaN', Phys. Status Solidi., C8, No.5, pp.1548-1551, 2011. In the paper, external quantum efficiencies of 1.7 ~ 2 times of Ni / Au transparent electrodes were obtained, but the specific operating voltage was not presented. . And in BJ Kim, 'Output Power Enhancement of GaN Light Emitting Diodes with p-type ZnO Hole Injection Layer', Applied Physics Letters, APL94, 103506 (2009), paper, about 40% light output than Ni / Au transparent electrode It was reported that it was obtained but could not provide the operating voltage accordingly. YR Ryu, Synthesis of p-type ZnO Films Journal of Crystal Growth, 216, pp. 330-334, 2000, reported that P-type ZnO (As) was grown on GaAs substrates using PLD equipment. SD Kirby, 'Improved Conductivity of ZnO through Co-doping with In and Al', Thin Solid Films, 517, pp.1958-1960, 2009., reported that Al-In co-doping ZnO was grown by RF sputtering method. However, no specific reference was made to the device. Tae Hoon Kim, `` Inhanced Optical Output of Tunel Junction GaN-based Light Emitting Didoes with Transparent Conducting Al and Ga-doped ZnO Thin Films '', Japanese Journal of Applied Physics 49, 091002, 2010, in the paper, using RF Magnetron Sputtering By using Al-Ga co-doped ZnO thin film, the external quantum efficiency was 1.7 times higher than that of Ni / Au transparent electrode, which was about 23%, but the operating voltage was very high.

Jammy Ben-Yaacov, 'Properties of In-doped ZnO Film Grown by MOCVD on GaN (0001) Templates', Journal of Electronics Materials, Vol. 39, No. 5, 2010., in the paper, 1.82x10 ¹⁹ / cm ³ , 185 ohm / sq. Although the electrical characteristics were obtained, the results for the specific devices were not reported. Chun-Ju Tun, 'Enhanced Light Output of GaN-based Power LEDs with Transparent Al-doped ZnO Current Spreading Layer', IEEE PHOTONICS TECHNOLOGY LETTERS, VOL.18, NO.1, PP.274-276, 2006, in the paper, In Ni / AZO and NiO _x / AZO, the light output is 38.2% and 60.6% higher than that of Ni / Au transparent electrode, and accordingly, it is 5.13V and 4.06V at 350mA, respectively, below 3.3V of ITO transparent electrode in mass production. Compared to the value, the value is very high and the actual light output is evaluated very low. Dea-Kue Hwang, 'ZnO Thin Film and Light-Emitting Diodes', Journal of Phys. D. Appl, Phys. 40, R387-412, 2007, Review article, mentioned thin film growth, doping control and resistive contact of devices, but failed to comment on the specific electrical properties of the device. Yang Hua, `` Light Extraction Efficiency Enhancement of GaN-based Light Emitting Diodes by a ZnO Current Spreading Layer '', Journal of Semiconductors Vol.39, No.9, 2009, in the paper, 20mA Operation of Ni / Au and ITO Transparent Electrodes Although the external quantum efficiency was reported to be 93% and 35%, respectively, it was reported that the operating voltage is 7 ~ 8V, which is very high due to the high contact resistance.

In general, as a doping source of a ZnO thin film having n-type electrical conductivity, Group III elements such as B, Al, Ca, In, and the like, and F, Cl, H, etc. may be used to easily form an n-type ZnO thin film. P, As, N, C, Li, F, Na, etc. are used as doping sources for ZnO thin films with p-type electrical conductivity, but oxygen vacancies, native defects, and automatic compensation in forming ZnO thin films It is very difficult to form a p-type ZnO thin film because a non-radiative defect center does not contribute to electrical conductivity due to the self compensation effect and thus has n-type ZnO characteristics. In order to solve this problem, a co-doped technique for n-type / p-type impurity doping sources such as Ga-N, F-Ni, Ga-C, and Ga-H has recently been proposed to provide high holes. Although studies on p-type ZnO thin films with carriers are being actively conducted, there are no reports showing satisfactory results. Specifically, in US 6,291,085, as-doped p-ZnO thin films are formed on an n-GaAs substrate by using pulsed laser deposition (PLD), and the doping concentration, mobility, and specific resistance of the holes are 10 ¹⁵ / cm ³ , 1, respectively. Although the electrical characteristics of ˜50 cm ² / Vsec and 1 ohm.cm are obtained, the present invention relates to an n / p-bonded ZnO light emitting device using a p-type ZnO single crystal thin film instead of a transparent electrode. In US 6,458,673, H-Ga co-doped n-GaN thin films are formed on a glass substrate by using pulse radar deposition (PLD) to present high light transmittance and high electron concentration. Development was not presented. In US 6,527,858, p-type ZnO single crystal thin films having low resistance as N-Ga (C-In) co-doped using molecular beam epitaxy (MBE) are described, but p / n is not applied to transparent electrodes. The present invention relates to a bonded ZnO light emitting device, and a light emitting device for improving light transmittance and electrical conductivity as a transparent electrode is not disclosed. In the case of US 6,896,731, p-n ZnO single crystal thin films having low resistance were grown by secondary doping of F-Ga co-doped and Mg and Be elements using molecular beam epitaxy (MBE). -It is intended to be applied to a bonded ZnO light emitting device, but the content of actual light transmittance and electrical conductivity as a transparent electrode is not disclosed. In addition, US 7,608,308 relates to p-ZnO single crystal thin film layers of p / n-bonded ZnO light-emitting devices by forming P-Li co-doped p-ZnO single crystals using pulsed laser deposition (PLD), but as a transparent electrode. There is no disclosure of light transmittance and electrical conductivity.

SUMMARY OF THE INVENTION In order to overcome the above problems, an object of the present invention is to provide a transparent thin film comprising a plurality of ZnO thin films having high light transmittance and high electrical conductivity at the same time, a light emitting device including the same, and a method of manufacturing the same. Each ZnO thin film included in the ZnO thin film is doped with n-type impurities such as Ga, p-type impurities such as As, or simultaneously n-type impurities such as Ga and p-type impurities such as As. do.

Another object of the present invention is to use n- such as Ga using at least one of molecular beam epitaxy (MBE), organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), and atomic layer epitaxy (ALE). A transparent thin film in which a plurality of ZnO thin films, in particular, ZnO single crystal thin films in which a dop-type impurity is doped, a p-type impurity such as As is doped, or an n-type impurity such as Ga and a p-type impurity such as As are simultaneously doped The present invention provides a method for manufacturing a highly efficient light emitting device having high light output, low operating voltage and high reliability, as well as being applicable to mass production.

In order to achieve the above objects, according to one aspect of the invention, the composition formula of Al _x In _y Ga _(1-xy) N, (0≤x≤1, 0≤y≤1, 0≤x + y≤1) A nitride semiconductor light emitting device having: a substrate; a buffer layer formed on the substrate; a first electrode contact layer formed on the buffer layer; a first clad layer formed on the first electrode contact layer; and formed on the first clad layer A multi-layered transparent electrode formed on the active layer, the second cladding layer formed on the active layer, the second electrode contact layer formed on the second cladding layer, the second electrode contacting layer, and a plurality of ZnO thin films stacked thereon; Wherein at least some of the ZnO thin films are doped with n-type impurities which are at least one selected from the group consisting of Group III elements of B, Al, Ga, In and F, Cl, H, or Group V of N, P, As, Sb P-type impurities, which are at least one selected from the group consisting of an element and Li, Na, and C, Doped or formed by simultaneously doping the n-type impurity and the p-type impurity, a first electrode pad formed on an upper side of the first electrode contact layer, and a second electrode formed on an upper side of the transparent electrode A nitride semiconductor light emitting device including a pad can be provided.

In an exemplary embodiment, the n-type impurity is Ga, and the p-type impurity is As. In addition, at least a portion of the ZnO thin films of the plurality of ZnO thin films may be different in thickness from other ZnO thin films. The transparent electrode may be a multi-layered structure in which a ZnO thin film doped with n-type impurities and a ZnO thin film doped with p-type impurities are alternately stacked a plurality of times. The thickness of each of the ZnO thin film is characterized in that the same. The transparent electrode may be a multi-layered structure in which a ZnO thin film doped with the p-type impurity and a ZnO thin film doped with the n-type impurity are alternately stacked a plurality of times. The thickness of each of the ZnO thin film is characterized in that the same. In addition, the transparent electrode has a multi-layered structure in which the ZnO thin film doped with the n-type impurity and the ZnO thin film doped with the p-type impurity are stacked. The thickness of each of the ZnO thin film is characterized in that the same. In addition, the transparent electrode has a multi-layered structure in which the ZnO thin film doped with the p-type impurity and the ZnO thin film doped with the n-type impurity are stacked. The thickness of each of the ZnO thin film is characterized in that the same. In addition, the transparent electrode has a multi-layered structure in which a ZnO thin film doped with the n-type impurity and the p-type impurity and a ZnO thin film doped with the n-type impurity are stacked. The thickness of the ZnO thin film doped with the n-type impurity is thinner than the thickness of the ZnO thin film that is simultaneously doped with the n-type impurity and the p-type impurity. In addition, the transparent electrode has a multi-layered structure in which the ZnO thin film doped with the n-type impurity, the ZnO thin film doped with the p-type impurity and the ZnO thin film doped with the n-type impurity are stacked. do. The thickness of the ZnO thin film doped with the n-type impurity is thinner than the thickness of the ZnO thin film doped with the p-type impurity or the thickness of the ZnO thin film doped with the n-type impurity. . The transparent electrode is formed by stacking a ZnO thin film doped with the n-type impurity, a ZnO thin film doped with the n-type impurity and the p-type impurity, and a ZnO thin film doped with the n-type impurity. It is characterized in that the multi-layered structure. Wherein the thickness of the ZnO thin film doped with the n-type impurity and the thickness of the ZnO thin film doped with the n-type impurity are the thickness of the ZnO thin film simultaneously doped with the n-type impurity and the p-type impurity. It is characterized by a thinner than. In addition, each ZnO thin film is characterized in that the ZnO single crystal thin film. In addition, the n-type impurity of the n-type impurity and the p-type impurity which is simultaneously doped is the main cause for improving the electrical characteristics, the p-type impurity is the main cause for improving the optical characteristics do.

According to another aspect of the present invention, a transparent thin film has a multilayer structure in which a plurality of ZnO thin films are laminated, and at least some ZnO thin films are formed from a group consisting of Group III elements of B, Al, Ga, In, and F, Cl, H. The at least one selected n-type impurity is doped, or the at least one p-type impurity selected from the group consisting of Group V elements of N, P, As, Sb and Li, Na, C is doped, or the n-type impurity And the p-type impurity can be provided at the same time to provide a transparent thin film.

According to another aspect of the present invention has a multi-layer structure in which a plurality of ZnO thin film is laminated, at least some ZnO thin film is at least one selected from the group consisting of Group III elements of B, Al, Ga, In and F, Cl, H Phosphorus n-type impurities are doped, or p-type impurities which are at least one selected from the group consisting of Group V elements of N, P, As, and Sb and Li, Na, and C are doped, or the n-type impurities and the p It is possible to provide a light emitting device comprising a transparent thin film, characterized in that the -type impurities are formed by co-doped.

According to another aspect of the present invention, a method of forming a transparent thin film includes laminating a plurality of ZnO thin films, wherein at least some of the ZnO thin films are group III elements of B, Al, Ga, In and F, Cl, H At least one n-type impurity selected from the group consisting of doped or at least one p-type impurity selected from the group consisting of Group V elements of N, P, As, and Sb and Li, Na, C, or It is possible to provide a method for forming a transparent thin film, wherein the n-type impurity and the p-type impurity are simultaneously doped.

According to another aspect of the present invention, a method of manufacturing a light emitting device includes the step of forming a transparent thin film, wherein the forming of the transparent thin film includes a process of laminating a plurality of ZnO thin film, at least a portion of the ZnO thin film Group III elements of B, Al, Ga, In and at least one n-type impurity selected from the group consisting of F, Cl, H are doped, or Group V elements of N, P, As, Sb and Li, Na, C It is possible to provide a method of manufacturing a light emitting device, characterized in that the at least one p-type impurity selected from the group consisting of doped, or the n-type and the p-type impurity is formed by co-doped.

According to the present invention, the following effects can be expected.

According to the present invention, ZnO thin films, in particular, are doped with n-type impurities such as Ga, p-type impurities such as As, or co-doped n-type impurities such as Ga and p-type impurities such as As. A transparent thin film in which a plurality of ZnO single crystal thin films are laminated, a light emitting device including the same, and a method of manufacturing the same can be provided.

In addition, according to the present invention, at least one of molecular beam epitaxy (MBE), organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), and atomic layer epitaxy (ALE) is used. A transparent thin film in which a plurality of ZnO thin films, in particular, ZnO single crystal thin films in which a dop-type impurity is doped, a p-type impurity such as As is doped, or an n-type impurity such as Ga and a p-type impurity such as As are simultaneously doped By forming, it is possible to provide a method of manufacturing a high-efficiency light emitting device having high light output, low operating voltage and high reliability as well as being applicable to mass production.

In addition, according to the present invention, it is relatively rich in reserve compared to the indium (In) of the ITO material, doped with n-type impurities such as Ga based on zinc (Zn) which can improve the manufacturing cost, or As Maximize economics by using ZnO thin films, in which a plurality of ZnO single crystal thin films are laminated, in which a p-type impurity is doped or a n-type impurity such as Ga and a p-type impurity such as As are simultaneously stacked A transparent thin film, an AlInGaN-based nitride semiconductor light emitting device including the same, and a method of manufacturing the same can be provided.

In addition, the present invention is not limited to AlInGaN-based nitride semiconductor light emitting devices, and can be applied to various application fields such as touch pads, organic EL, solar cells, etc., which can replace conventional ITO materials. A transparent electrode and its manufacturing method can be provided.

1 is a cross-sectional view schematically showing a laminated structure of a light emitting device using a conventional AlInGaN-based nitride semiconductor.

FIG. 2 is a flowchart schematically illustrating a process of forming a ZnO thin film having a multilayer structure used as a transparent electrode of an AlInGaN-based nitride semiconductor light emitting device according to a preferred embodiment of the present invention. FIG.

3 is a cross-sectional view schematically showing a laminated structure of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to an embodiment of the present invention.

4 is a schematic cross-sectional view of a stacked structure of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to another exemplary embodiment of the present invention.

5 is a schematic cross-sectional view of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to an exemplary embodiment of the present invention.

6 is a schematic cross-sectional view of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to another exemplary embodiment of the present invention.

7 is a schematic cross-sectional view of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to another preferred embodiment of the present invention.

8 is a schematic cross-sectional view of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to another preferred embodiment of the present invention.

9 is a schematic cross-sectional view of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to another preferred embodiment of the present invention.

FIG. 10 illustrates n-type (Ga) and p-type (As) impurities doped in a ZnO thin film grown on a second electrode contact layer of a light emitting device using an AlInGaN-based nitride semiconductor according to an exemplary embodiment of the present invention. Graph showing current-voltage characteristics.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

The present invention relates to ZnO thin films, in particular ZnO single crystals, which are doped with n-type impurities such as Ga, p-type impurities such as As, or simultaneously doped with n-type impurities such as Ga and p-type impurities such as As. The present invention relates to a transparent thin film in which a plurality of thin films are stacked, a light emitting device including the same, and a manufacturing method thereof. According to the present invention, a transparent thin film in which an n-type impurity such as Ga is doped, a p-type impurity such as As is doped, or an n-type impurity such as Ga and a p-type impurity such as As is simultaneously doped. For convenience, the ZnO single crystal thin film is not limited thereto. In addition, the light emitting device according to the present invention is a nitride semiconductor light emitting device, in particular Al _x In _y Ga _(1-xy) N, (0≤x≤1, 0≤y≤1, 0≤x + y≤1) for convenience of description. The nitride semiconductor light emitting device having a compositional formula of 1, but is not limited thereto. In addition, the transparent thin film according to the present invention is formed using the molecular beam epitaxy method (MBE) for convenience of description, but is not limited thereto. Preferably, organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), It is also included in the technical scope of the present invention to form a transparent thin film using at least one of the atomic layer epitaxy method (ALE). Hereinafter, for convenience of description of the present invention, the transparent thin film may be doped with n-type impurities such as Ga, p-type impurities such as As, or n-type impurities such as Ga and p-type such as As. A multi-layered transparent thin film in which a plurality of ZnO thin films, in particular ZnO single crystal thin films, which are simultaneously doped with impurities are laminated, and the light emitting device is Al _x In _y Ga _(1-xy) N, (0≤x≤1, 0≤y≤1 , A nitride semiconductor light emitting device (hereinafter referred to as AlInGaN-based nitride semiconductor light emitting device) having a composition formula of 0 ≦ x + y ≦ 1, and a ZnO thin film is formed by using a molecular beam epitaxy method (MBE). In addition, for convenience of description of the present invention, n-type impurities and p-type impurities which are simultaneously doped or individually doped to individual ZnO thin films are mainly Ga and As, but are not limited thereto. The type impurity is at least one selected from the group consisting of Group III elements of B, Al, Ga, In and F, Cl, H, and the p-type impurities are Group V elements of N, P, As, Sb, Li, Na, The at least one selected from the group consisting of C is also included in the technical scope of the present invention.

Individual single crystal ZnO thin films capable of forming a transparent electrode according to the present invention, for example, single crystal ZnO thin films doped with n-type impurities such as Ga (hereinafter referred to as ZGO (ZnO: Ga) thin films or ZGO thin films or ZGO single crystal thin films). , Monocrystalline ZnO thin films doped with p-type impurities such as As (hereinafter referred to as ZAO (ZnO: As) thin films or ZAO thin films or ZAO single crystal thin films), or n-type impurities such as Ga and p-type impurities such as As The molecular beam epitaxy equipment (hereinafter referred to as MBE equipment) for forming this co-doped single crystal ZnO thin film (hereinafter referred to as ZGAO (ZnO: Ga-As) thin film or ZGAO single crystal thin film) is largely a sample. It is divided into charging room, processing room and growth room. In particular, the growth chamber of the ZnO thin film, preferably the ZnO single crystal thin film, is separated by a gate valve in order to maintain a clean growth environment in which ultra-high vacuum and contaminants are removed as much as 10 ^-9 torr. 2 is a flowchart schematically illustrating a process of forming a ZnO thin film having a multilayer structure used as a transparent electrode of an AlInGaN-based nitride semiconductor light emitting device according to a preferred embodiment of the present invention. Referring to FIG. 2, the MBE equipment for forming a ZnO thin film having a multi-layer structure used as a transparent electrode of an AlInGaN-based nitride semiconductor light emitting device according to the present invention is an ultra-high vacuum equipment of 10 ^-9 torr or less and has an atomic level in a very clean environment. This has the advantage of growing the film very precisely. MBE equipment for manufacturing a ZGAO thin film and an AlInGaN-based nitride semiconductor light emitting device employing the same according to the present invention is Al, In, Ga, Zn, As, Sb metal tablet (tablet) with high purity, preferably 99.999% or more in a high vacuum growth environment. And a crucible in which each metal source is housed, and a heater is settled, and is composed of independent individual cells controlling the flow rate. As the source gas, an oxygen (O ₂ ) gas of high purity, preferably 99.9999% or more, is used by dissociating using an RF plasma. In order to improve the crystallinity of the ZGAO thin film, ZGO thin film, ZAO thin film, preferably ZGAO single crystal thin film, ZGO single crystal thin film, ZAO single crystal thin film which can form a transparent thin film having a multilayer structure according to the present invention, the substrate is heated. desirable. As described above, the n-type impurity which is co-doped or individually doped to the ZnO thin film is preferably Ga, but at least one selected from the group consisting of Group III elements of B, Al, Ga, In and F, Cl, H As a p-type impurity which is simultaneously doped or individually doped, it is preferably As, but may be at least one selected from the group consisting of Group V elements of N, P, As, and Sb, and Li, Na, and C. ZGAO thin film, ZGO thin film, ZAO thin film, preferably ZGAO single crystal thin film, ZGO single crystal thin film, which can form a transparent thin film of the multi-layer structure according to the present invention is a light emitting structure comprising a substrate that is formed of a ZAO single crystal thin film is high Mg-doped p-GaN thin film having an unstable hexagonal structure, such as Mg, Mg-H composite, excess Mg that remains without being activated as a carrier as a carrier on the surface, but is not limited thereto. In the growth method, a ZGAO thin film, a ZGO thin film, a ZAO thin film, preferably a ZGAO single crystal thin film, a ZGO single crystal thin film, and a ZAO single crystal thin film, which can form a transparent thin film having a multilayer structure according to the present invention, first, an AlInGaN-based nitride semiconductor light emitting device After the light emitting structure including the substrate having the structure is heated up to an appropriate heat treatment temperature, a ZGAO thin film, a ZGO thin film, a ZAO thin film, preferably a ZGAO single crystal thin film and a ZGO single crystal, which may form a transparent thin film having a multilayer structure according to the present invention. The temperature is lowered to a temperature for forming the thin film, the ZAO single crystal thin film (step 201). The heat treatment temperature of the mother substrate is preferably in the range of about 500 ° C to 700 ° C. Simultaneously with the heat treatment process of the light emitting structure including the substrate, the temperature of each cell where the Al, In, Ga, Mg, Zn, As source is fixed is maintained at the optimum growth temperature condition for optimal flow rate control (step 203). . The optimal growth temperature in each cell may vary depending on the growth conditions of the ZGAO thin film, ZGO thin film, ZAO thin film, preferably ZGAO single crystal thin film, ZGO single crystal thin film, ZAO single crystal thin film, which can form a transparent thin film having a multilayer structure. The amount and structure of the material contained in each cell may vary. For example, the temperature of the cell corresponding to the Zn source is appropriately in the range of about 300 ° C. to 600 ° C., and the temperature of the cell corresponding to the Ga source is suitably in the range of about 500 ° C. to 800 ° C. and corresponds to the As source. The temperature of the cell is appropriately in the range of about 200 ℃ to 400 ℃, within this range can be set the optimum flow conditions of each cell. Appropriate temperature range of each cell described above is only one embodiment, it will be apparent to those skilled in the art that the present invention can be variously changed according to equipment specifications.

With the optimum growth environment prepared in steps 201 and 203, the optimal growth temperature is determined for the light emitting structure including the substrate, and the substrate is rotated after the optimal growth temperature is determined (step 205). Thereafter, the shutter of the cell provided with each material is opened to the light emitting structure including the rotating substrate correspondingly to the process (step 207). In step 207, an oxygen source obtained by dissociating oxygen (O ₂ ) gas using an RF plasma may be further supplied to correspond to the process. The shutter of each cell is opened to correspond to the process so that the material contained in the cell reaches the light emitting structure including the substrate by evaporation, and an oxygen source is further supplied to correspond to the process, thereby providing a multilayer structure according to the present invention. ZGAO thin film, ZGO thin film, ZAO thin film, preferably ZGAO single crystal thin film, ZGO single crystal thin film, ZAO single crystal thin film that can form a transparent thin film is uniformly grown, ZGO thin film in which Ga, an n-type doping source, is individually doped , a transparent thin film comprising a plurality of ZAO thin films individually doped with As, a p-type doping source, and a ZGAO thin film simultaneously doped with Ga, an n-type doping source, and As, a p-type doping source. By forming a transparent electrode having a high light transmittance and a high electrical conductivity due to the low resistance characteristic (step 209). In the process described above, most of the Zn source is combined with oxygen to form a single crystal thin film of zinc oxide (ZnO). Oxygen is generally present in a molecular state, but in order to proceed with the process according to the present invention, it is dissociated and supplied in an atomic state, and preferably, an RF plasma method may be used. After the formation of a transparent electrode formed of a multilayer structure including at least one of a ZGAO thin film, a ZGO thin film, a ZAO thin film, preferably a ZGAO single crystal thin film, a ZGO single crystal thin film, and a ZAO single crystal thin film according to the present invention, The shutter of the cell is closed (step 211).

3 is a cross-sectional view schematically showing a laminated structure of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to an embodiment of the present invention, Figure 4 is a preferred embodiment of the present invention A cross-sectional view schematically showing a stacked structure of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to another embodiment. 3 and 4 exemplarily illustrate a state in which a ZnO thin film (including a ZnO single crystal thin film) according to the present invention is employed in a light emitting device, in particular, a light emitting device using an AlInGaN-based nitride semiconductor. The scope is not to be construed as being limited thereto. The light emitting device using the AlInGaN-based nitride semiconductor shown in FIGS. 3 and 4 includes an "Emitting Light Diode (LED)" and a "Laser Diode (LD)". In the light emitting device using the AlInGaN nitride semiconductor according to the present invention shown in Figs. 3 and 4, the same parts as those of the conventional light emitting device using the conventional AlInGaN nitride semiconductor shown in Fig. 1 are omitted. Let's do it. In the light emitting device using the AlInGaN nitride semiconductor according to the present invention shown in FIGS. 3 and 4, the n-type nitride semiconductor layer 305 serving as the substrate 301, the buffer layer 303, and the first electrode contact layer is provided. The n-type nitride cladding layer 307, the active layer 309, the p-type nitride cladding layer 311 and the p-type nitride semiconductor layer 313 are sequentially stacked. Flat type (315 in FIG. 3) having a flat surface or n / p-type second electrode contact layers 315 and 415 on the p-type nitride semiconductor layer 313, or rough type having a rough surface (rough type) can be formed. On the second electrode contact layers 315 and 415, a thin p-InGaN layer or an n ⁺ -InGaN layer, an InGaN / InGaN superlattice layer, an n-InGaN / GaN superlattice layer, etc. 315, 415 may be further formed corresponding to the surface conditions of. That is, when the second electrode contact layer 315 is flat, a thin p-InGaN layer or n ⁺ -InGaN layer, InGaN / InGaN superlattice layer, An InGaN / GaN superlattice layer may be formed, and when the second electrode contact layer 415 is a rough type, a rough p-InGaN layer having a rough thickness or n ⁺ − on the second electrode contact layer 316. An InGaN layer, an InGaN / InGaN superlattice layer, an n-InGaN / GaN superlattice layer, or the like may be formed. The rough type according to the invention can be carried out by controlling the Mg flow rate. The substrate 301, the buffer layer 303, the n-type nitride semiconductor layer 305, the n-type nitride cladding layer 307, the active layer 309, and the p-type according to the present invention. A thin p-InGaN layer formed over the nitride clad layer 311, the p-type nitride semiconductor layer 313, the second electrode contact layers 315 and 316, and the second electrode contact layers 315 and 415. ^{The +} -InGaN layer, the InGaN / InGaN superlattice layer, the n-InGaN / GaN superlattice layer, etc. are preferably grown by organic metal chemical vapor deposition (MOCVD), but is not limited thereto. In the light emitting device according to the present invention shown in FIGS. 3 and 4, the impurity source used as the n-type dopant is silicon (Si), and the doping concentration is about 10 ¹⁷ / cm ³ to 10 ¹⁸ / cm ³ , respectively. In particular, in the case of the n-type nitride semiconductor layer 305 which is in electrical contact with the first electrode pad 319 which is an n-type electrode pad and used as the first electrode contact layer, the silicon doping concentration is 1 to 5 × 10 ^18. It is about / cm ³ and grows in the thickness range of 2-4 micrometers. The impurity source used as the p-type dopant is magnesium (Mg), and after performing an activation process, the doping concentration of the carrier, which is a carrier, is in the range of about 1 to 5 x 10 ¹⁷ / cm ³ . In particular, the second electrode contact layers 315 and 415 are electrically contacted with the second electrode pad 321, which is a p-type electrode pad, to grow within a thickness range of 10 nm to 500 nm, and a hole concentration as a carrier by an activation process. Maximize. Similar to the light emitting device using the conventional AlInGaN nitride semiconductor described with reference to FIG. 1, the second electrode contact layer included in the light emitting device using the AlInGaN nitride semiconductor according to the present invention shown in FIGS. 3 and 4 ( 315 and 415 have a high resistance / Ga-rich rough surface including excess Mg and Mg-H composites (10 ² / cm ³ to 10 ⁴ / cm ³ ) inside and on the surface of the single crystal thin film. Therefore, in order to obtain a high light output high-efficiency light emitting device by uniform spread and injection of applied current to the effective light emitting area of the InGaN / InGaN active layer 309 on the second electrode contact layers 315 and 415, the state of the light emitting structure ( By accurately grasping the crystal structure, surface roughness, and electrical properties, there is a need for an effective interface control technology with a transparent electrode formed later. 3 and 4, as described with reference to FIG. 2 on the second electrode contact layers 315 and 415, the transparent electrode formed of a multilayer structure of a transparent electrode, in particular, a ZnO thin film according to the present invention ( 317 and 417 may be formed corresponding to the surface state of the second electrode contact layers 315 and 415. That is, when the second electrode contact layer 315 is a flat type, a transparent electrode 317 (in case of FIG. 3) formed in a multilayer structure of a flat ZnO thin film is formed on the second electrode contact layer 315. When the two-electrode contact layer 415 is a rough type, it is preferable that a transparent electrode 417 (in the case of FIG. 4) formed of a multilayer structure of a rough-type ZnO thin film is formed on the second electrode contact layer 316. It is not limited to this. Finally, first electrode pads 419 and 421 and second electrode pads 321 and 421 for wire bonding are formed as shown in FIGS. 3 and 4. As shown in FIG. 1, the second electrode pads 321 and 421 may be formed to be directly connected to the second electrode contact layers 315 and 415. In the present invention, the ZnO thin film required to form a transparent electrode of a light emitting device having a high efficiency / high reliability having a high light output, a low operating voltage and a long life by replacing the ITO material used as a transparent electrode of a conventional light emitting device The light transmittance can be maximized by the single crystal thin film having the same crystal structure as the second electrode contact layers 315 and 415 of the first light emitting structure, and the electrical characteristics of the carrier can be improved by simultaneous doping of n- / p-type impurities. It is controlled to minimize the contact resistance, which has the advantage of increasing the electrical conductivity. The ZnO thin film according to the present invention is characterized in that holes are supplied by interfacial control with the light emitting structure, in particular, the second electrode contact layers 315 and 417, and doping of p-type impurities such as As. There is a characteristic.

The transparent electrodes 317 and 318 formed of a multilayer structure of a ZnO thin film, which is a transparent electrode according to the present invention, include a light emitting structure including a substrate having a hexagonal crystal structure in a c-axis growth direction, particularly a second electrode contact layer 315. , 415) can be grown as a single crystal thin film having the same hexagonal crystal structure, and because the resistance can be adjusted through optimal doping control, it has excellent light transmittance and electrical conductivity compared to the conventional amorphous and polycrystalline ZnO thin film. The second electrode contact layers 315 and 415 of the light emitting device using the AlInGaN-based nitride semiconductors have a host material of Ga-rich, nitrogen vacancies and excess Mg, Mg of 10 ² / cm ³ or more after the activation process. The -H complex and the like are mixed and are in a relatively unstable state with high resistance and rough surface. According to a preferred embodiment of the present invention, when the transparent electrodes 317 and 417 formed of a multilayer structure of the ZnO thin film are grown on the second electrode contact layer 315 and 415, the ZnO thin film is initially grown in a high vacuum state. When the lower layer of the transparent electrode formed of a multilayer structure is a ZGAO single crystal thin film or a ZGO single crystal thin film, Zn, a host material, is replaced with a Ga site on the Ga-rich surfaces of the second electrode contact layers 315 and 415 (Zn _Ga A ZnO-doped GaN layer localized at the interface between the ZGAO single crystal thin film or ZGO single crystal thin film, which is a lower layer of the transparent electrode formed of a multilayer structure of the ZnO thin film, and the second electrode contact layers 315 and 415 is formed. In addition, the Mg-H composite that remains locally on the surface of the second electrode contact layers 315 and 316 after the activation process undergoes OH bonding by oxygen (O), which is a host of the ZnO single crystal thin film, thereby desorbing hydrogen (H). Finally, a host remaining as a dangling bond at the interface between the ZGAO single crystal thin film or ZGO single crystal thin film, which is a lower layer of the transparent electrode formed of a multilayer structure of the ZnO thin film, and the second electrode contact layers 315 and 415 ZgO single crystal thin film or ZGO single crystal thin film, which is a lower layer of a transparent electrode formed of a multi-layer structure of ZnO thin film, is formed by Mg substitution with Ga sites (Mg _Ga ), and a p-doped layer having a very high hole doping concentration as a local carrier is formed. Contact resistance may be significantly lowered at the interface between the second electrode contact layers 315 and 415. Subsequently, the ZGAO single crystal thin film or ZGO single crystal thin film, which is the lower layer of the transparent electrode formed of the multilayer structure of the ZnO thin film, grows in the c-axis direction as the growth proceeds, but a native defect formed during oxygen voids and crystal growth. High resistance due to an asymmetric stoichiometric composition ratio with Optimum doping techniques should be applied to improve low electrical conductivity by these non-radiative centers.

The transparent electrode formed of the multilayer structure of the ZnO thin film according to the present invention is a multilayer structure in which a ZAO single crystal thin film and a ZGO single crystal thin film are alternately stacked a plurality of times (see FIG. 5 and the description thereof), or alternately by adjusting the thickness of the ZnO thin film. Or a multi-layer structure in which three kinds of ZnO single-crystal thin films of ZGO single crystal thin film, ZGAO single crystal thin film and ZAO single crystal thin film are laminated (see FIGS. 9 and its description). Can be. 5 to 9 and the description thereof are not limited to the technical scope of the present invention, n-type impurities such as Ga are doped, p-type impurities such as As are doped, n-type impurities such as Ga and As ZnO thin film, in particular, a multi-layered transparent thin film in which a plurality of ZnO single crystal thin films are simultaneously stacked with p-type impurities, such as a light emitting device and a manufacturing method thereof, will be included in the technical scope of the present invention.

5 is a schematic cross-sectional view of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to an exemplary embodiment of the present invention. As shown in FIG. 5, the transparent electrode formed of a multi-layer structure according to the present exemplary embodiment includes a ZAO single crystal thin film and a pair of ZGO single crystal thin films, or a pair of ZGO single crystal thin films and a ZAO single crystal thin film stacked multiple times. A ZGO single crystal thin film is alternately laminated, or a ZGO single crystal thin film and a ZAO single crystal thin film are alternately laminated. In this embodiment, the growth time of each ZnO single crystal thin film was 30 seconds, and a pair of ZGO single crystal thin films and ZAO single crystal thin films or a pair of ZAO single crystal thin films and ZGO single crystal thin films 50 times were laminated to have a final thickness of 320 nm. Subsequently, a chip having a size of 500250 μm ² was manufactured by performing an LED chip process on the AlInGaN-based light emitting device to check characteristics such as an operating voltage (VF) and an optical output (P _o ) at an applied current of 20 mA. In the present embodiment, the light output was 18.1 mW at the operating voltage (VF) 3.56 V in the LED wavelength band of 446 nm. In the LED light emitting device having the same thickness in the same wavelength band and a transparent electrode made of a single thin film of a simultaneously doped ZGAO single crystal, the operating voltage (VF) and light output were 3.34V and 15.65mW, respectively. Therefore, the LED light emitting device to which the transparent electrode of the multilayer structure as shown in FIG. 5 of the present invention has an improved light output compared to the LED light emitting device to which the transparent electrode made of a single thin film of ZGAO single crystal doped with Ga and As simultaneously is applied. It is evaluated to have.

6 is a schematic cross-sectional view of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to another exemplary embodiment of the present invention. As shown in FIG. 6, the transparent electrode formed of a multilayer structure according to the present embodiment has a multilayer structure consisting of a pair of ZAO single crystal thin films and a ZGO single crystal thin film, or a pair of ZGO single crystal thin films and a ZAO single crystal thin film. The thickness of each ZnO single crystal thin film constituting the transparent electrode in this embodiment is thicker than that of each ZnO single crystal thin film constituting the transparent electrode as shown in FIG. 5. In this embodiment, in particular, when the ZAO single crystal thin film is stacked on the bottom and the ZGO single crystal thin film is formed on the top to form a multilayer structure, the growth time of each ZnO single crystal thin film is 25 minutes, and the ZAO single crystal thin film on the bottom and the ZGO single crystal thin film on the The laminate structure was made to have a final thickness of 320 nm. Subsequently, a chip having a size of 500250 μm ² was manufactured by performing an LED chip process on the AlInGaN-based light emitting device to check characteristics such as an operating voltage (VF) and an optical output (P _o ) at an applied current of 20 mA. In this embodiment, the light output was 19.7 mW at 3.52 V of operating voltage (VF) in the LED wavelength band of 446 nm. In the LED light emitting device having the same thickness in the same wavelength band and a transparent electrode made of a single thin film of a simultaneously doped ZGAO single crystal, the operating voltage (VF) and light output were 3.34V and 15.65mW, respectively. Therefore, the LED light emitting device to which the transparent electrode of the multilayer structure as shown in FIG. 6 of the present invention is further improved in light output compared to the LED light emitting device to which the transparent electrode composed of a single thin film of ZGAO single crystal doped with Ga and As simultaneously. It is evaluated to have an effect.

7 is a schematic cross-sectional view of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to another preferred embodiment of the present invention. As shown in FIG. 7, a transparent electrode formed of a multilayer structure according to the present exemplary embodiment has a lower thickness than that of a ZGAO single crystal thin film doped with n-type impurity Ga and p-type impurity As and a ZGAO single crystal thin film thereon. It has a multilayer structure including a Ga-doped ZGO single crystal thin film which is a thin n-type impurity. The growth time of the ZGAO single crystal thin film is 45 minutes, the growth time of the ZGO single crystal thin film is 5 minutes, and the transparent electrode, which is a laminated structure of the ZGAO single crystal thin film and the ZGO single crystal thin film, has a final thickness of 320 nm. Subsequently, a chip having a size of 500250 μm ² was manufactured by performing an LED chip process on the AlInGaN-based light emitting device to check characteristics such as an operating voltage (VF) and an optical output (P _o ) at an applied current of 20 mA. In this embodiment, the ZGO single crystal thin film doped with Ga, which is an n-type impurity, is adopted to reduce the sheet resistance and improve the electrical conductivity. As the thickness increases, the sheet resistance decreases but the light output decreases. In the present embodiment, the light output was 17.2 mW at an operating voltage (VF) of 3.37 V in the LED wavelength band of 446 nm. In the LED light emitting device having the same thickness in the same wavelength band and a transparent electrode made of a single thin film of a simultaneously doped ZGAO single crystal, the operating voltage (VF) and light output were 3.34V and 15.65mW, respectively. Therefore, the LED light emitting device to which the transparent electrode of the multilayer structure as shown in FIG. 7 of the present invention has an improved light output compared to the LED light emitting device to which the transparent electrode made of a single thin film of ZGAO single crystal doped with Ga and As simultaneously is applied. It is evaluated to have. When the thickness of the ZGAO single crystal thin film is the same and the growth time of the Ga-doped ZGO single crystal thin film which is n-type impurity is increased from 5 minutes to 10 minutes, the operating voltage of the LED light emitting device is reduced to 3.32V, The output is reduced to 16.24mW. This results in a lower operating voltage due to the reduction of the sheet resistance of the ZGO single crystal thin film and the improvement of the electrical properties with the metal pad, but the compensation effect at the joint surface doped with n-type impurity Ga and p-type impurity As. It is assumed that the optical power is lowered due to the compensation effect.

8 is a schematic cross-sectional view of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to another preferred embodiment of the present invention. As shown in FIG. 8, the transparent electrode formed of the multilayer structure according to the present exemplary embodiment includes a ZGO single crystal thin film doped with Ga as an n-type impurity and a ZAO single crystal thin film doped with As as a p-type impurity thereon; A ZGO single crystal thin film doped with Ga, which is an n-type impurity, is stacked thereon, and the lower ZGO single crystal thin film has a multilayer structure that is thinner than the upper ZAO single crystal thin film and the ZGO single crystal thin film. The growth time of the lower ZGO single crystal thin film is 5 minutes, and the growth time of the upper ZAO single crystal thin film and the ZGO single crystal thin film is 25 minutes, respectively, and the transparent electrode which is the stacked structure of the lower ZGO single crystal thin film and the upper ZAO single crystal thin film and the ZGO single crystal thin film is final. It was to have a thickness of 320nm. Subsequently, a chip having a size of 500250 μm ² was manufactured by performing an LED chip process on the AlInGaN-based light emitting device to check characteristics such as an operating voltage (VF) and an optical output (P _o ) at an applied current of 20 mA. In the present embodiment, the light output was 14.2 mW at an operating voltage (VF) of 3.90 V in the LED wavelength band of 446 nm. In the LED light emitting device having the same thickness in the same wavelength band and a transparent electrode made of a single thin film of a simultaneously doped ZGAO single crystal, the operating voltage (VF) and light output were 3.34V and 15.65mW, respectively. Accordingly, the LED light emitting device to which the transparent electrode of the multilayer structure as shown in FIG. 8 of the present invention is applied has the electrical characteristics and the light output as compared with the LED light emitting device to which the transparent electrode made of a single thin film of ZGAO single crystal doped with Ga and As simultaneously. It is evaluated that the characteristic is degraded. This is because the p / n junction is formed at the junction with the second electrode layer of the AlInGaN-based light emitting device to increase the depletion region, and thus the operating voltage is high. As a result, the current injection efficiency is lowered and consequently the light output is also reduced. I guess. Therefore, the thickness of the ZGO single crystal thin film doped with n-type impurities forming the junction with the second electrode layer of the AlInGaN-based light emitting device is thinned with respect to the LED light emitting device shown in FIG. 8, and the doping concentration is increased to ˜10 ²⁰ / cm ³ . The increase in the formation of tunnel junctions can effectively improve the operating voltage and light output.

9 is a schematic cross-sectional view of a light emitting device using an AlInGaN-based nitride semiconductor including a transparent electrode formed of a multilayer structure of a ZnO thin film according to another preferred embodiment of the present invention. As shown in FIG. 9, the transparent electrode formed of the multilayer structure according to the present embodiment includes a ZGO single crystal thin film doped with Ga as an n-type impurity at the bottom thereof, Ga as a n-type impurity and As as a p-type impurity thereon. ZGAO single crystal thin films doped simultaneously with ZGA single crystal thin films doped with Ga, which is doped with n-type impurities, are stacked on top of each other, and the lower and upper ZGO single crystal thin films have a thinner multilayer structure than the intermediate ZGAO single crystal thin films. The growth time of the lower and upper ZGO single crystal thin films is 5 minutes, respectively, and the growth time of the intermediate ZGAO single crystal thin films is 45 minutes, and the transparent electrode which is a laminated structure of the lower ZGO single crystal thin film, the middle ZGAO single crystal thin film and the upper ZGO single crystal thin film is The final thickness was 320nm. Subsequently, a chip having a size of 500250 μm ² was manufactured by performing an LED chip process on the AlInGaN-based light emitting device to check characteristics such as an operating voltage (VF) and an optical output (P _o ) at an applied current of 20 mA. In the present embodiment, the light output was 14.1 mW at the operating voltage (VF) of 3.42 V in the LED wavelength band of 446 nm. In the LED light emitting device having the same thickness in the same wavelength band and a transparent electrode made of a single thin film of a simultaneously doped ZGAO single crystal, the operating voltage (VF) and light output were 3.34V and 15.65mW, respectively. Therefore, the LED light emitting device to which the transparent electrode of the multi-layer structure as shown in FIG. 9 of the present invention is applied has the electrical characteristics and the light output compared to the LED light emitting device to which the transparent electrode made of a single thin film of ZGAO single crystal doped with Ga and As simultaneously. It is evaluated that the characteristic is degraded. As described with reference to FIG. 8, the ZGO single crystal thin film doped with Ga, the upper n-type impurity in contact with the metal pad, has a low sheet resistance to improve electrical conductivity, thereby reducing operating voltage through smooth contact with the metal pad. In addition, since the p / n junction is formed at the junction with the second electrode layer of the AlInGaN-based light emitting device to increase the depletion region, the operation voltage is high. As a result, the current injection efficiency is lowered, and consequently, the light output is also reduced. Therefore, as described above, the thickness of the ZGO single crystal thin film doped with n-type impurities forming the junction with the second electrode layer of the AlInGaN based light emitting device is increased, and the doping concentration is increased to ˜10 ²⁰ / cm ^3. By forming a tunnel junction, it is considered that the operating voltage and the light output can be effectively improved.

FIG. 10 illustrates n-type (Ga) and p-type (As) impurities doped in a ZnO thin film grown on a second electrode contact layer of a light emitting device using an AlInGaN-based nitride semiconductor in accordance with a preferred embodiment of the present invention. A graph showing the current-voltage characteristics. In order to examine the electrical characteristics of a light emitting device using an AlInGaN nitride semiconductor according to an impurity doped in a ZnO thin film, the inventor emits light using MBE equipment on the second electrode contact layer of the light emitting device using a rough AlInGaN nitride semiconductor. A ZnO single crystal thin film of about 2500 kV thick having the same hexagonal crystal structure as the structure was grown. In general, the resistance of semiconductor materials depends on the concentrations of n-type and p-type impurities to be doped, and thus the electrical properties of the doping of n-type (Ga) and p-type (As) impurities and their simultaneous doping are investigated. In order to confirm, the inventors fixed the thickness of the ZnO thin film to 2500Å, and then the undoped ZnO thin film, Ga doped ZnO thin film, As doped ZnO thin film (As doped ZnO) and Ga-As After the co-doped ZnO thin film (Ga-As co-doped ZnO) was grown to form an indium electrode to have the same distance, the current-voltage characteristics were confirmed. In addition, the inventors divided the light emitting structure of the AlInGaN-based nitride semiconductor light emitting device including a 2-inch sapphire substrate into quarter pieces to confirm electrical characteristics, thereby securing accuracy of each doping effect and effects. Referring to FIG. 10, in the case of the ZnO thin film not doped at an applied voltage of 0.2 V, a very high resistance value of 5305 ohms can be seen. These results are attributed to the causes such as intrinsic crystal defects and oxygen (O ₂ ) vacancy that occur during the growth of the undoped ZnO single crystal thin film. It can be seen that it adversely affects, resulting in a high resistance value. However, in the case of Ga-doped ZnO thin film, the resistance value at the same applied voltage is 6.7ohm lower than that of the non-doped ZnO thin film resistance of 5305ohm appears to be negligible. This result is believed to be due to the substitution of Ga in the place of the oxygen (O ₂ ) pores to form a plurality of Ga-O and Zn-Ga bonds. In the case of the As-doped ZnO thin film, it can be seen that the resistance increases again to 397 ohm at the same applied voltage. These results indicate that As is not only substituted with Zn sites, but also with the sites of oxygen (O ₂ ) pores, the resistance value is increased again compared to that of Ga-doped ZnO thin film by Zn-As and As-O bonding. Inferred. In the case of Ga-As co-doped ZnO thin film, it can be seen that the resistance value is 17.6 ohm at the same applied voltage, which is slightly higher than that of the Ga-doped ZnO thin film but very low compared to that of the As-doped ZnO thin film. have. These results indicate that Ga and As are co-doped, thereby reducing the resistance caused by the Ga-O and Ga-Zn bonds and increasing the number of Ga-O and Ga-Zn bonds during the growth of the host ZnO thin film having intrinsic crystal defects and oxygen (O ₂ ) pores. It proceeds up to Ga-As bond simultaneously with many As-Zn bonds and As-O bonds, and it is inferred to have a very low resistance value compared to the undoped ZnO thin film or As doped ZnO thin film. Based on the electrical characteristics as shown in Figure 5, it is possible to form a ZGAO thin film having a high electrical conductivity according to the low resistance that can be used as a transparent electrode of the AlInGaN-based nitride semiconductor light emitting device. As shown in FIG. 10, the inventors have undoped ZnO, Ga-doped ZnO, and As-doped ZnO thin films. ) And sheet resistance (Rs) values of Ga-As co-doped ZnO thin films (Ga-As co-doped ZnO) are 6.5Kohm / sq, 7.2ohm / sq, 536ohm / sq, and 45ohm / sq, respectively. It was confirmed that the results were consistent with the current-voltage characteristic curve of the resistance value change due to the doping effect.

As described above, Ga-As co-doped ZnO (ie, ZGAO single crystal thin film) or Ga-doped ZnO (ie, ZGO single crystal thin film) that is n-type impurity or As-doped ZnO (ie, ZAO single crystal) which is p-type impurity Thin film), among the n-type impurities such as Ga and the p-type impurities such as As, the n-type impurities such as Ga are the main causes for improving the electrical characteristics. As described with reference to FIGS. 5 and 6, Among the n-type impurities such as Ga and the p-type impurities such as As, it can be seen that the p-type impurities such as As are the main cause for improving the characteristics such as light output. According to the present invention, an AlInGaN-based nitride having a hexagonal single crystal structure using molecular beam epitaxy (MBE), organic chemical vapor deposition (MOCVD), atomic layer deposition (ALD), atomic layer epitaxy (ALE), or the like. The light emitting structure itself of the semiconductor light emitting device has a hexagonal crystal structure with almost no lattice mismatch, and n-type impurities such as Ga which improves electrical characteristics and p-type impurities such as As which improves the optical characteristics. By simultaneously doping and separately layering n-type and p-type impurities, ZnO thin films (ie, ZGAO, ZGO, and ZAO single crystal thin films) having two or more stacked structures can be grown to single crystals, which can be applied to mass production. It is possible to provide a method of manufacturing a high-efficiency light emitting device having electrical characteristics of high light output, low resistance and high current conductivity.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and variations without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The scope of protection of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

Claims (23)

1. In a nitride semiconductor light emitting device having a composition formula of Al _x In _y Ga _(1-xy) N, (0≤x≤1, 0≤y≤1, 0≤x + y≤1),

   Board;

   A buffer layer formed on the substrate;

   A first electrode contact layer formed on the buffer layer;

   A first clad layer formed on the first electrode contact layer;

   An active layer formed on the first clad layer;

   A second clad layer formed on the active layer;

   A second electrode contact layer formed on the second clad layer;

   A multi-layered transparent electrode formed on the second electrode contact layer and having a plurality of ZnO thin films stacked therein, wherein at least some of the ZnO thin films are a group consisting of Group III elements of B, Al, Ga, and In, F, Cl, and H. At least one n-type impurity selected from doped, or at least one p-type impurity selected from the group consisting of Group V elements of N, P, As, Sb and Li, Na, C is doped, or the n-type An impurity and the p-type impurity are formed by simultaneous doping;

   A first electrode pad formed on an upper side of the first electrode contact layer; And

   A nitride semiconductor light emitting device comprising a second electrode pad formed on an upper side of the transparent electrode.
2. The method of claim 1,

   And the n-type impurity is Ga and the p-type impurity is As.
3. The method of claim 1,

   At least a portion of the ZnO thin films of the plurality of ZnO thin films are nitride semiconductor light emitting device, characterized in that the thickness is different from other ZnO thin film.
4. The method of claim 1,

   The transparent electrode

   And a ZnO thin film doped with the n-type impurity and a ZnO thin film doped with the p-type impurity in a multilayer structure in which a plurality of alternating layers are alternately stacked.
5. The method of claim 4, wherein

   The nitride semiconductor light emitting device of claim 1, wherein the thickness of each ZnO thin film is the same.
6. The method of claim 1,

   The transparent electrode

   And a ZnO thin film doped with the p-type impurity and a ZnO thin film doped with the n-type impurity in a multilayer structure in which a plurality of alternating layers are alternately stacked.
7. The method of claim 6,

   The nitride semiconductor light emitting device of claim 1, wherein the thickness of each ZnO thin film is the same.
8. The method of claim 1,

   The transparent electrode

   And a ZnO thin film doped with the n-type impurity and a ZnO thin film doped with the p-type impurity.
9. The method of claim 8,

   The nitride semiconductor light emitting device of claim 1, wherein the thickness of each ZnO thin film is the same.
10. The method of claim 1,

    The transparent electrode

    And a ZnO thin film doped with the p-type impurity and a ZnO thin film doped with the n-type impurity.
11. The method of claim 10,

    The nitride semiconductor light emitting device of claim 1, wherein the thickness of each ZnO thin film is the same.
12. The method of claim 1,

    The transparent electrode

    And a ZnO thin film doped with the n-type impurity and the p-type impurity and a ZnO thin film doped with the n-type impurity.
13. The method of claim 12,

    And the thickness of the ZnO thin film doped with the n-type impurity is thinner than the thickness of the ZnO thin film doped with the n-type impurity and the p-type impurity.
14. The method of claim 1,

    The transparent electrode

    The nitride semiconductor light emitting device of claim 1, wherein the ZnO thin film doped with the n-type impurity, the ZnO thin film doped with the p-type impurity, and the ZnO thin film doped with the n-type impurity are stacked. .
15. The method of claim 14,

    The thickness of the lower ZnO thin film doped with the n-type impurities is thinner than the thickness of the ZnO thin film doped with the p-type impurities or the thickness of the upper ZnO thin film doped with the n-type impurities Semiconductor light emitting device.
16. The method of claim 1,

    The transparent electrode

    A multi-layered structure in which the ZnO thin film doped with the n-type impurity, the ZnO thin film doped with the n-type impurity and the p-type impurity and the ZnO thin film doped with the n-type impurity are stacked A nitride semiconductor light emitting device characterized by the above-mentioned.
17. The method of claim 16,

    The thickness of the lower ZnO thin film doped with the n-type impurity and the thickness of the upper ZnO thin film doped with the n-type impurity correspond to the thickness of the ZnO thin film simultaneously doped with the n-type impurity and the p-type impurity. A nitride semiconductor light emitting device, characterized in that the thinner than.
18. The method of claim 1,

    Each ZnO thin film is a nitride semiconductor light emitting device, characterized in that the ZnO single crystal thin film.
19. The method of claim 1,

    The n-type impurity among the n-type impurity and the p-type impurity which are simultaneously doped is the main cause for improving the electrical characteristics, and the p-type impurity is the main cause for improving the optical characteristics. Nitride semiconductor light emitting device.
20. As a transparent thin film,

    Has a multi-layered structure in which a plurality of ZnO thin films are stacked,

    At least some ZnO thin films are doped with group III elements of B, Al, Ga, In and n-type impurities selected from the group consisting of F, Cl, H, or group V elements of N, P, As, and Sb. And a p-type impurity which is at least one selected from the group consisting of Li, Na, and C, or is formed by simultaneously doping the n-type impurity and the p-type impurity.
21. A light emitting device comprising the transparent thin film of claim 20.
22. As a method of forming a transparent thin film,

    Including a process of laminating a plurality of ZnO thin film,

    At least some ZnO thin films are doped with group III elements of B, Al, Ga, In and n-type impurities selected from the group consisting of F, Cl, H, or group V elements of N, P, As, and Sb. And at least one p-type impurity selected from the group consisting of Li, Na, and C, or the n-type impurity and the p-type impurity are simultaneously doped.
23. As a manufacturing method of a light emitting element,

    Including forming a transparent thin film,

    The transparent thin film is a method of manufacturing a light emitting device, characterized in that formed by the method of claim 22.

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