KR-20260062268-A - Nitride Light emitting diode

Abstract

The present invention discloses a nitride-based semiconductor light-emitting device that improves the luminous efficiency of a light-emitting structure grown on a reflective film. The present invention is characterized first by depositing an amorphous reflective film on a crystalline or amorphous substrate and improving the luminous efficiency of a nitride-based light-emitting device grown on top of the reflective film through the reflectivity of the reflective film, and is characterized second by increasing the light extraction efficiency by reducing the directional angle of light emitted from the light-emitting device.

Inventors

• 김동환
• 노민수
• 김극
• 김왕근
• 최철재
• 지연홍

Assignees

• 김동환
• 노민수
• 김극
• 김왕근
• 최철재
• 지연홍

Dates

Publication Date

20260507

Application Date

20241028

Claims (8)

1. A reflective film formed on the upper surface of a substrate and composed of an amorphous dispersed Bragg reflector (DBR) in which two or more materials with different refractive indices are cross-deposited; A non-conductive buffer layer formed using sputtering to grow a nitride on top of the above reflective film; A light-emitting structure comprising a non-conductive semiconductor layer, a first conductive semiconductor layer, an active layer, and a second conductive semiconductor layer sequentially stacked on top of the above buffer layer; A transparent electrode layer sequentially stacked on top of the second conductivity type semiconductor layer; and a metal electrode, comprising A nitride-based semiconductor light-emitting device that operates as an RCLED (Resonance Cavity LED) by means of the reflectance of the DBR in the reflective film formed in the lower layer and the reflectance of the metal electrode formed in the upper layer.
2. In paragraph 1, A nitride-based semiconductor light-emitting device characterized by a reduction in the directional angle of light emitted downward due to the overlap phenomenon between the wavelength of light generated in the active layer and the wavelength of the resonance cavity, and the selective reflection phenomenon according to the angle of incidence in the reflective film.
3. In paragraph 1, The above reflective film is A nitride-based semiconductor light-emitting device composed of a combination of SiO2/TiO2, characterized in that its reflectivity is greater than 10% and less than 95%.
4. In paragraph 1, The above reflective film is A nitride-based semiconductor light-emitting device characterized by being composed of a combination of two or more oxide layers with different refractive indices among SiO2/Ta2O5, Al2O3/TiO2, and HfO2/ZrO2 oxide layers, wherein the reflectance of the combination is greater than 10% and less than 95%.
5. In paragraph 1, The above buffer layer It consists of an ANN layer or a GaN layer, and A nitride-based semiconductor light-emitting device characterized in that the above-mentioned AIN layer or GaN layer is formed on the upper surface of the above-mentioned reflective film using sputtering.
6. In paragraph 1, The above active layer A nitride-based semiconductor light-emitting device comprising InGaN and characterized by emitting light in the blue wavelength range in the direction of the reflective film.
7. In paragraph 1, The above metal electrode is A nitride-based semiconductor light-emitting device characterized by being made of a material having a reflectance of 50% or more.
8. In paragraph 1, A nitride-based semiconductor light-emitting device characterized by the difference between the wavelength of the Fabry-Perot resonance formed by the above-mentioned reflective film and metal electrode and the wavelength of light emitted by the above-mentioned active layer being within +/- 10nm.

Description

Nitride-based semiconductor light-emitting diode The present invention relates to a technology for improving the luminous efficiency of a luminescent structure grown on a reflective film, and more specifically, to a nitride semiconductor light-emitting device in which the luminous efficiency of the nitride-based semiconductor light-emitting device grown on a reflective film is improved by the reflectivity of the reflective film. A light-emitting diode (LED) is a light-emitting device that emits light when current is applied. Light-emitting diodes are known for their excellent energy-saving effects as they emit high-efficiency light at low voltages. Recently, the brightness of light-emitting diodes has been greatly improved, and they are being widely applied in various devices such as backlight units for display devices like LCDs, electronic billboards, indicators, and home appliances. Light-emitting devices containing compounds such as AlGaInP, AlGaN, AlGaInN, AlGaAs, AlInGaAs, and InGaAsP have many advantages, such as having easily adjustable band gap energy, and can be used in various ways as light-emitting devices, light-receiving devices, and various diodes. In particular, light-emitting devices such as light-emitting diodes (LEDs) or laser diodes (LDs) using group 3-5 or group 2-6 compound semiconductor materials can produce various colors, including near-infrared, red, green, blue, and ultraviolet light, thanks to the development of thin-film growth technology and device materials. Light-emitting devices that produce blue and ultraviolet light can also produce more efficient white light by using fluorescent materials or combining colors, and have advantages such as low power consumption, semi-permanent lifespan, fast response speed, safety, and environmental friendliness compared to conventional light sources such as fluorescent lamps and incandescent lamps. Recently, active research and development is underway on technology to fabricate visible light-emitting diodes in micro-size and use them as pixels for high-resolution displays. In addition, research and development on using visible light-emitting diodes for visible light communication has recently been actively underway, as well as on implementing light-emitting diodes on inexpensive amorphous substrates. In particular, research and development on micro-sized light-emitting diodes is actively underway to secure high-speed modulation characteristics in visible light communication using nitride-based light-emitting diodes. However, most nitride-based semiconductor light-emitting devices based on conventional technology have been grown on crystalline substrates. Although nitride-based light-emitting devices grown on amorphous substrates are also being studied, there are issues such as the complex manufacturing process and the need for further improvement in terms of light efficiency. FIG. 1 is a cross-sectional view showing the structure of a nitride-based semiconductor light-emitting device according to the present invention. FIGS. 2a to 2e are cross-sectional views illustrating the manufacturing process of a nitride-based semiconductor light-emitting device according to the present invention. Figure 3 is a graph showing the calculated reflectance values according to the number of pairs and respective thicknesses of the reflective film according to the present invention. Figure 4 is a graph showing the phenomenon in which the beam angle of light emitted from a nitride-based RCLED according to the present invention becomes narrower compared to the beam angle of a general LED. Figure 5 is a graph showing the phenomenon in which the external quantum efficiency of a nitride-based semiconductor light-emitting device according to the present invention changes due to the lower DBR reflectance. Embodiments of the present invention will be described in detail below with reference to the accompanying drawings. First, it should be noted that in assigning reference numerals to the components of each drawing, the same components are given the same reference numeral whenever possible, even if they are shown in different drawings. Furthermore, in describing the present invention, detailed descriptions of related known components or functions are omitted if they are deemed obvious to those skilled in the art or could obscure the essence of the invention. FIG. 1 is a cross-sectional view showing the structure of a nitride-based semiconductor light-emitting device according to the present invention, FIG. 2a to 2e are cross-sectional views showing the manufacturing process of a nitride-based semiconductor light-emitting device according to the present invention, FIG. 3 is a graph showing the calculated values of reflectance according to the number of pairs and respective thicknesses of the reflective film according to the present invention, FIG. 4 is a graph showing the phenomenon in which the directional angle of light emitted from a nitride-based RCLED according to