Blue light LED growth method for improving carrier recombination efficiency

Abstract

The invention relates to the technical field of semiconductor photoelectricity, in particular to a blue light LED growing method for improving carrier recombination efficiency, which comprises the following steps of: S1, respectively extending a Buffer layer, a 3D layer, a GR layer and an N-GaN layer on sapphire according to a conventional blue light LED manufacturing process; and S2, a layer of N-Al0. 2Ga0. 8N is additionally arranged behind the N-GaN layer, and SiH4, TMAl and TEGa are introduced at the same time. And S3, continuing to be consistent with the conventional blue light LED manufacturing process, and extending Q1, Q2 and Q3 quantum well layers. And S4, according to the Last Barrier layer, a conventional Al < 0.3 > Ga < 0.7 > N + AlN layer is changed into an Al < 0.7 > Ga < 0.3 > N-Al < 0.65 > Ga < 0.35 > N gradient layer, and the time is shortened by half. S5, a hole storage acceleration layer is formed on the rear portion of the Last Barrier layer in an epitaxial mode, P-In0. 2Ga0. 8N is introduced, a shallow energy level layer is formed, the time is consistent with that of S4, and S6, an Al0. 45Ga0. 55N-Al0. 5Ga0. 5N gradient layer is formed on the rear portion of the Last Barrier layer in an epitaxial mode again, and the time is half of that of S5. The quantum well structure is redesigned, and the n-AlGaN and the hole storage acceleration layer are added to realize the deceleration of electrons in the quantum well and the acceleration of holes, so that the main light-emitting region is migrated to a deep level, the carrier recombination efficiency is improved, and the light-emitting efficiency is further improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of semiconductor optoelectronic technology, in particular to a blue LED epitaxial growth method for improving carrier recombination efficiency, and particularly relates to a technical scheme for improving internal quantum efficiency of an LED by optimizing quantum well structure and introducing a hole storage acceleration layer. BACKGROUND

[0002] Light emitting diodes (LEDs) are widely used in visible light communication, optoelectronic medical treatment, rapid non-destructive testing and other multi-system fields due to their low power consumption, small size, wide spectral range and other advantages. With the development of epitaxial growth technology and multi-quantum well technology, the internal quantum efficiency of LEDs has been greatly improved, and the internal quantum efficiency of super-high brightness LEDs can reach 85%. The great demand for LEDs in portable / wearable electronic devices and low-power displays has led to the gradual trend of low-power consumption, long life and miniaturization of blue LED devices. The application scenarios under small current have higher requirements for the internal quantum efficiency of the epitaxial layer of the LED, and the light efficiency still needs to be improved. At present, due to the fact that the mobility of electrons is much greater than that of holes, the main light-emitting region in the quantum well is always located in the Q3 quantum well close to the P-GaN region. If the internal quantum efficiency is to be further improved, holes need to be injected into the deep well layer (Q2 and part of the Q1 layer). In the traditional epitaxial structure, in order to prevent electron leakage, a high-potential AlN material is usually used as an electron blocking layer (EBL layer), but the high potential also blocks the injection of holes.

[0003] Therefore, how to improve the ability of hole injection into the quantum well while preventing electron leakage has become one of the difficulties in improving the light efficiency of the LED. SUMMARY

[0004] The present application aims to provide a blue LED growth method for improving carrier recombination efficiency, which re-designs the quantum well structure, increases n-AlGaN and hole storage acceleration layer to realize deceleration of electrons and acceleration of holes in the quantum well, so that the main light-emitting region migrates to a deep level, increases the carrier recombination efficiency, and further improves the light efficiency, thereby solving the problems raised in the background technology.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical scheme: a blue LED growth method for improving carrier recombination efficiency, comprising the following steps:

[0006] S1. Consistent with the conventional blue LED process, a Buffer layer, a 3D layer, a GR layer and a N-GaN layer are epitaxially grown on a sapphire.

[0007] S2. A layer of N-AlGaN is added after the N-GaN layer. 0.2 Ga 0.8N, while SiH4, TMAl and TEGa are simultaneously introduced.

[0008] S3. Continue with the conventional blue LED process, epitaxial Q1, Q2, Q3 quantum well layer.

[0009] S4. The Last Barrier layer is changed from conventional Al 0.3 Ga 0.7 N+AlN layer to Al 0.7 Ga 0.3 N-Al 0.65 Ga 0.35 N gradient layer, time is shortened by half.

[0010] S5. After the Last Barrier layer, epitaxial hole storage acceleration layer, P-In 0.2 Ga 0.8 N is introduced to form a shallow level layer, the time is consistent with S4.

[0011] S6. Again epitaxial Al 0.45 Ga 0.55 N-Al 0.5 Ga 0.5 N gradient layer, time is half of S5.

[0012] S7. Continue with the conventional blue LED process, epitaxial LP, HP, PP layer.

[0013] Compared with the prior art, the beneficial effects of the present application are:

[0014] The present application achieves the deceleration of electrons in the quantum well and the acceleration of holes by redesigning the quantum well structure, increasing n-AlGaN and hole storage acceleration layer, so that the main light emitting area migrates to the deep level, increases the carrier recombination efficiency, and further improves the light emitting efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0015] In order to more clearly illustrate the specific embodiments of the present application or the technical solutions in the prior art, the drawings needed in the specific embodiments or prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0016] Fig. 1 Comparison of conventional LED epitaxial layers and epitaxial layers of the present application.

[0017] Fig. 2 Brief illustration for the purpose of hole storage acceleration layer.

[0018] Fig. 3Energy level height of hole storage acceleration layer. DETAILED DESCRIPTION

[0019] The technical solutions in the embodiments of the present application will be apparently and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by those skilled in the art without creative work belong to the protection scope of the present application.

[0020] Please refer to Figs. 1 to 3 , the present application provides a technical solution:

[0021] S1. Consistent with the conventional blue light LED process, respectively epitaxial Buffer layer, 3D layer, GR layer, N-GaN layer on sapphire.

[0022] S2. After N-GaN layer, increase a layer of N-Al 0.2 Ga 0.8 N, while inputting SiH4, TMAl and TEGa.

[0023] S3. Continue to be consistent with the conventional blue light LED process, epitaxial Q1, Q2, Q3 quantum well layer.

[0024] S4. Last Barrier layer will be the conventional Al 0.3 Ga 0.7 N+AlN layer into Al 0.7 Ga 0.3 N-Al 0.65 Ga 0.35 N gradient layer, time is shortened by half.

[0025] S5. After Last Barrier layer, epitaxial a layer of hole storage acceleration layer, input P-In 0.2 Ga 0.8 N, forming a shallow energy level layer, time is consistent with S4.

[0026] S6. Again epitaxial Al 0.45 Ga 0.55 N-Al 0.5 Ga 0.5 N gradient layer, time is half of S5.

[0027] S7. Continue to be consistent with the conventional blue light LED process, epitaxial LP, HP, PP layer.

[0028] In the present embodiment, the place inconsistent with the conventional blue light LED process is that N-Al 0.2 Ga 0.8N, S4-6 steps increase a shallow level layer, as a hole storage acceleration layer, theoretically taking this measure is conducive to gathering a large number of holes before LB, improving the hole concentration to realize the speed of hole mobility, so that the hole has enough kinetic energy to migrate to the deep quantum well layer, N-Al 0.2 Ga 0.8 The role of N is mainly to realize the deceleration of the injected electrons, so as to introduce the recombination region to the deep quantum well layer.

[0029] The following Fig. 1 For the comparison of the improved part of the application and the conventional LED, it can be seen that the main modification step is to increase N-Al 0.2 Ga 0.8 N, and the LB and EBL layer is replaced by LB+hole storage layer+LB.

[0030] Fig. 2 The schematic diagram of the mechanism of the hole storage layer can be seen that in the conventional LED, due to the blocking of the high barrier of EBL, it is difficult for the hole to realize effective transition. After the improvement of the application, the space for hole storage is provided behind the LB, which is conducive to gathering a large number of holes before the LB, and the LB layer is provided with a gradient, which optimizes the hole injection efficiency by using the concentration difference driving effect (the concentration difference driving effect refers to the directional diffusion movement of carriers due to the existence of concentration gradient, which is one of the important mechanisms of carrier transport in semiconductor devices), which is an effective way to realize the speed of hole mobility, so that the hole has enough kinetic energy to migrate to the deep quantum well layer.

[0031] From Fig. 3 It can be seen from the conventional LED that the IQE is close to 80% at small current, and after the improvement of the application, the efficiency is further improved, more than 80%, and the current does not appear a large amount of decay at large current. It is conducive to the improvement of the light efficiency of LED.

[0032] Finally, it should be pointed out that: the above embodiments are only used to illustrate the technical solutions of the application, but not to limit them; although the application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or make equivalent replacement for part or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the application.

Claims

1. A blue LED growth method for improving carrier recombination efficiency, characterized by: Comprising the following steps: S1. In accordance with the conventional blue light LED process, respectively epitaxial Buffer layer, 3D layer, GR layer, N-GaN layer on sapphire; S2. Add a layer of N-Al after the N-GaN layer 0.2 Ga 0.8 N, while flowing SiH4, TMAl and TEGa; S3. Continue in accordance with the conventional blue light LED process, epitaxial Q1, Q2, Q3 quantum well layer; S4. The last barrier layer of Al 0.3 Ga 0.7 N+AlN layer is replaced by Al 0.7 Ga 0.3 N-Al 0.65 Ga 0.35 N grading layer, the time is shortened by half; S5. Epitaxial a hole storage acceleration layer after the Last Barrier layer, P-In 0.2 Ga 0.8 N, form a shallow level layer, the time is consistent with S4; S6. Again epitaxial Al 0.45 Ga 0.55 N-Al 0.5 Ga 0.5 N graded layer, half the time of S5; S7. Continue in accordance with the conventional blue light LED process, epitaxial LP, HP, PP layer.

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