KR100765387B1 - Luminance device having quantum well - Google Patents

Abstract

The present invention relates to a light-emitting and light-receiving element having a quantum well, the light emitting and receiving elements to respectively generate optical and electrical energy in accordance with an external electrical and light energy, Al _x Ga _{1 - x} N film well and AlN film It provides a light emitting and light receiving device comprising an active layer having a barrier. In this way, an AlGaN film is used as a well in the quantum well structure, and an AlN film is used as a barrier to provide an active layer having good quality and excellent electron blocking, and improving the optical output by improving the characteristics of the active layer.

UV LED, Quantum Well, AlN, Well, Barrier, Active Layer, PHOTO DETECTOR

Description

Light emitting device having a quantum well structure {Luminance device having quantum well}

1 is a cross-sectional conceptual view of a light emitting device having a quantum well structure according to the present invention.

2 is a conceptual diagram briefly showing a quantum well structure according to the present invention.

<Explanation of symbols for main parts of the drawings>

10: substrate 20, 40: semiconductor layer

30: active layer 50: transparent electrode layer

60: P type pad

The present invention relates to a light-emitting and light-receiving device having a quantum well structure, and to a well composed of AlGaN-AlN having an increased aluminum content.

A quantum well is a structure formed by inserting a thin semiconductor layer having an energy bandgap smaller than the energy bandgap of a semiconductor layer between different semiconductor layers. A carrier of an electron or a hole is trapped in an energy barrier and moves in both directions. Indicates. Optical devices having a quantum well can generate light having a large amount of light even at a small driving voltage, and research on this is being actively conducted. In addition, the application field of the device using the LED based on group III nitride is gradually expanding.

In particular, the Al content is gradually increased in the AlGaN wells for UV emission. When the Al content is increased, it becomes difficult to grow high quality AlGaN, and thus the efficiency of the quantum well is gradually decreased, resulting in a problem that the optical power of the light emitting device is very low.

Therefore, the present invention can improve the light output of the light emitting device by improving the characteristics of the active layer of the quantum well structure using AlN as a barrier layer when Al content is increased in the quantum well structure to solve the above problems. It is an object of the present invention to provide a light emitting and receiving element having a quantum well structure.

A device for generating light and electrical energy according to external electric and light energy according to the present invention, the device comprising an active layer having a well of an Al _x Ga _{1- x} N (0 ≦ x <1) film and a barrier between the AlN film. Provided is an element.

Here, the thickness of the well and the barrier is 5 to 1000 mm 3.

At this time, the base layer consisting of the well and the barrier is formed of 2 to 1000 layers.

The Al _x Ga _{1 - x} N film has a raw material mixed with TMGa or TEGa, TMAl or TEAl under a temperature of 900 to 1300 ° C. and a pressure of 30 to 760 torr, and 0.01 to 10 μm / hour using NH ₃ . It is formed at a growth rate. At this time, the V / III molar concentration ratio of the Al _x Ga _{1 - x} N film is 50 to 50000.

The AlN film is formed at a growth rate of 0.01 to 10 µm / hour using TMAl or TEAl and NH ₃ at a temperature of 900 to 1300 ° C. and a pressure of 30 to 760 torr. At this time, the V / III molar concentration ratio of the AlN film is 50 to 50000.

Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention in more detail. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various forms, and only the embodiments are intended to complete the disclosure of the present invention, and to those skilled in the art to fully understand the scope of the invention. It is provided to inform you. Like numbers refer to like elements in the figures.

In the following examples, the light emitting device will be described.

1 is a conceptual cross-sectional view of a light emitting device having a quantum well structure according to the present invention. 2 is a conceptual diagram briefly showing the structure of a quantum well according to the present invention.

1 and 2, a light emitting device according to the present invention includes a first semiconductor layer 20 formed on a substrate 10 and an AlN barrier layer 32, 34, formed on the first semiconductor layer 20. An active layer 30 having a quantum well structure including a 36 and a second semiconductor layer 40 formed on the active layer 30 is included. In this case, a buffer layer may be formed between the substrate 10 and the first semiconductor layer 20. As the substrate 10, a sapphire substrate, a silicon substrate, SiC, or the like can be used. In addition, it is effective to use an N-type GaN layer as the first semiconductor layer 20, and to use an AlGaN layer doped with N-type impurities in this embodiment.

In addition, it is effective to use the AlGaN layer doped with P-type impurities as the second semiconductor layer 40. The transparent electrode 50 and the P-type pad 60 using ITO or the like are formed on the second semiconductor layer 40. Of course, an N-type pad may be formed on the first semiconductor layer 20. Of course, the structure of the light emitting device of the present invention is not limited to the vertical or horizontal device. That is, the active layer of the quantum well structure of the present invention can be applied to the light emitting device of any structure.

In addition, the active layer 30 according to the present embodiment includes well layers 31, 33, 35 of Al _x Ga _{1 -x} N (0 ≦ x <1) and barrier layers 32, 34, 36 of AlN. . That is, the well layer 31, 33, 35 has Al _x Ga _{1- x} N (0 ≦ x <1) interposed between the barrier layers 32, 34, 36 of AlN.

The active layer of the quantum well structure according to the present embodiment will be described in more detail as follows.

As illustrated in FIG. 2, the quantum well structure has a shape in which a plurality of wells A and barriers B are stacked. As the barrier B, AlN films 32, 34, and 36 having high conduction band energy and low valence band energy are used, and as well, Al _x Ga ₁ having low conduction band energy and high valence band energy. _-x N (0 ≦ x <1) films 31, 33, and 35 are used.

Preferably, a base layer obtained by sequentially growing a well A of Al _x Ga _{1- x} N (0 ≦ x <1) and a barrier B of 5 to 1000 mm thick (T2) in the order of 5 to 1000 mm thick (T1). It is preferable that (K) is formed from 2 to 1000 layers. Each well (A) and barrier (B) of the quantum well structure of the present invention is effective to form within the range of the above-described thickness, it is possible to form the same thickness of the well (A) and the barrier (B), They can be formed differently. In addition, a plurality of base layers K including the wells A and the barriers B may be laminated. In this case, the number of base layers K stacked in consideration of the thickness of the active layer 30 of the overall quantum well structure and the thickness of each well A and the barrier B may vary within the above range. . In addition, the thickness of each base layer K laminated can also be formed with the same thickness, and can also be formed also in different thickness.

To form the active layer 30 of the quantum well structure as described above, first, trimethylgallium (TMGa) or triethyl gallium (TEGa) and trimethylaluminum (TMAl) at a temperature of 900 to 1300 ℃ and a pressure of 30 to 760torr ) Or Al _x Ga _{1- x} N (0 ≦ x <1) film is grown at a growth rate of 0.01 to 10 μm / hour using a raw material mixed with triethylaluminum (TEAl) and NH ₃ . Herein, the ratio (V / III ratio) of trimethylgallium (TMGa) or triethyl gallium (TEGa) and / or trimethylaluminum (TMAl) or triethylaluminum (TEAl) to NH ₃ is preferably 50 to 50000. .

Here, the V / III ratio refers to the mole ratio in the reactor. In other words, the V / III ratio represents the ratio of NH ₃ , that is, the ratio of N in the NH _{3 to} Ga and / or Al. That is, it refers to the molar concentration ratio of N, Ga, and Al.

Next, in order to form the active layer 30 of the quantum well structure, first, using trimethylaluminum (TMAl) or triethylaluminum (TEAl) and NH ₃ at a temperature of 900 to 1300 ℃ and a pressure of 30 to 760torr The AlN film is grown at a growth rate of from 10 µm / hour. At this time, the V / III ratio of N and Al is in the range of 50 to 50000 to form an AlN film. Further, trimethylgallium (TMGa) or triethylgallium (TEGa) is added thereto to form an AlGaN film as a quantum well structure well, and an AlN film as a barrier.

Here, the target wavelength may be changed by changing the Al content and thickness in the active layer 30 of the quantum well structure. In other words, if the content of Al in the well increases the bend 증가 to increase the light of short wavelengths, when the thickness of the well increases the light of a long wavelength is emitted.

The above-described deposition process is repeated at least once to form an active layer having a quantum well structure having a multilayer well and a barrier. As necessary, Si or Mg may be doped into the AlN film and the AlGaN well.

As described above, using AlN as the barrier layer in the quantum well structure has better film quality and is more effective for electron blocking than using conventional AlGaN.

In addition, the device having the above-described structure can also be used as a light receiving device that generates electrical energy (current) in accordance with external light energy. When a reverse voltage is applied to a conventional diode, almost no current flows, but when light energy is applied to the active layer of the quantum well structure of the light receiving device according to the present embodiment, the current flows by light energy in a principle opposite to that of the light emitting device described above. That is, when the electrons in the active layer of the device is applied with light energy having a higher energy than the band 전자 energy, the electrons are moved, thereby causing a current to flow. At this time, the flow of current is proportional to the intensity of light applied. On the other hand, in order to use the device of the above-described structure as a light receiving device may further include a light concentrator for concentrating the light energy.

As described above, the present invention can provide an active layer having good quality and excellent electron blocking by using an AlGaN film as a well in an quantum well structure and using an AlNN film as a barrier.

In addition, the optical output can be improved by improving the characteristics of the active layer.

Although the invention has been described with reference to the accompanying drawings and the preferred embodiments described above, the invention is not limited thereto, but is defined by the claims that follow. Accordingly, one of ordinary skill in the art may variously modify and modify the present invention without departing from the spirit of the following claims.

Claims (7)

In the light emitting device having a quantum well structure, The wells of the Al _x Ga _1-x N (0≤x <1) film prepared with the V / III molar concentration ratios of V and III raw materials of 50 to 50000, and the V / III molar concentration ratios of V and III raw materials of 50 to 50000. A light emitting device having a quantum well structure comprising an active layer having a barrier of an AlN film made of 50000. The method according to claim 1, A light emitting device having a quantum well structure in which the wells and the barriers each have a thickness of 5 to 1000 micrometers. The method according to claim 1 or 2, The light emitting device having a quantum well structure in which the base layer consisting of the well and the barrier is formed of 2 to 1000 layers. The method according to claim 1 or 2, The _x Ga _1-x N film Al 900 at a temperature and a pressure of from 30 to 760torr to 1300 ℃ TMGa or TEGa and, TMAl or TEAl is mixed with raw material, of 0.01 to 10㎛ / hour growth rate using the NH ₃ A light emitting device having a quantum well structure formed of. delete The method according to claim 1 or 2, The AlN film has a quantum well structure formed at a temperature of 900 to 1300 ° C., a pressure of 30 to 760 torr, and a growth rate of 0.01 to 10 μm / hour using TMAl or TEAl and NH ₃ . delete

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