TW201415659A - LED with good electrical contact reflector - Google Patents

Abstract

This invention relates to an LED with a good electrical contact reflector applicable to an LED. The LED comprises sequentially stacked an N-type electrode, an N-type semiconductor layer, a light emitting layer and a P-type semiconductor layer, a reflector, a buffer layer, a combination layer, a permanent substrate, and one P-type electrode. Between the P-type semiconductor layer and the reflector is an intrinsic semiconductor layer, and the intrinsic semiconductor layer is diffused by the doping element of the P-type semiconductor layer and the material element of the reflector. Accordingly, the invention uses the intrinsic semiconductor layer diffused with the doping element of the P-type semiconductor layer and the material element of the reflector to form ohmic contact, so that the reflector and the P-type semiconductor layer form good electrical contact to enhance illumination efficiency and satisfy user demands.

Description

Light-emitting diode with good electrical contact mirror

The invention relates to a light-emitting diode, in particular to a light-emitting diode having a good electrical contact mirror.

Light Emitting Diode (LED), which has the characteristics of lightness, thinness, power saving, etc., has been widely used in lighting, traffic signs, advertising signs, etc., which is mainly composed of multiple epitaxial stacking of semiconductor materials. For example, a blue light-emitting diode is mainly composed of a gallium nitride-based (GaN-based) epitaxial film.

Please refer to FIG. 1 , which is a conventional vertical light-emitting diode comprising an N-type semiconductor layer 1 , a light-emitting layer 2 and a P-type semiconductor layer 3 constituting a sandwich structure, and the P-type semiconductor layer. 3, a mirror layer 4, a buffer layer 5, a bonding layer 6, a germanium substrate 7 and a P-type electrode 8 are disposed in sequence, and the surface of the N-type semiconductor layer 1 may be a roughening process to increase the light emission rate, and an N-type electrode 9 is provided. Accordingly, after the N-type electrode 9 and the P-type electrode 8 are applied with a voltage, the N-type semiconductor layer 1 supplies electrons, and the P-type The semiconductor layer 3 provides a hole, and the electrons are combined with the hole in the light-emitting layer 2 to generate light.

In order to increase the light extraction rate, the surface of the N-type semiconductor layer 1 may be roughened to form an irregular surface 1A, and the N-type electrode 9 is directly formed on the irregular surface 1A, thereby avoiding The generation of total reflection.

It is also known that the excitation light generated by the luminescent layer 2 has no directionality. Therefore, in order to increase the brightness, it is necessary to guide the excitation light to be emitted in the same direction. Conventionally, the arrangement of the mirror 4 can achieve this goal. By setting the mirror 4, the target for guiding the excitation light can be achieved. However, the material of the mirror 4 is made of silver, and the electrical contact between the silver and the P-type semiconductor layer 3 is poor, which may result in contact resistance. Raise, and reduce the luminous efficiency, and the technique used to use the sputtering method in the production of the mirror layer, and the sputtering uses the high-energy plasma to disperse and adhere the pre-plated metal to the target. High-energy plasma destroys the bond between gallium nitride and magnesium, resulting in increased contact resistance and reduced luminous efficiency.

Please refer to FIG. 2 again. In order to solve this problem, a thin layer of nickel 3A is formed between the mirror 4 and the P-type semiconductor layer 3, which can form an ohmic contact. While solving the problem of an increase in contact resistance, the nickel layer 3A has a light absorbing property, which directly absorbs the excitation light, resulting in a decrease in luminance, which also causes a decrease in luminous efficiency.

The main object of the present invention is to disclose a light-emitting diode having a good electrical contact mirror to reduce contact resistance and improve luminous efficiency.

The invention relates to a light-emitting diode with a good electrical contact mirror, which is applied to a light-emitting diode. The light-emitting diode comprises an N-type electrode, an N-type semiconductor layer and a light-emitting layer which are sequentially stacked. a P-type semiconductor layer, a mirror, a buffer layer, a bonding layer, a permanent substrate and a P-type electrode, and an intrinsic semiconductor layer is disposed between the P-type semiconductor layer and the mirror, and the intrinsic semiconductor layer The doping element of the P-type semiconductor layer and the material element of the mirror are diffused.

According to this, the intrinsic semiconductor layer diffused with the doping element of the P-type semiconductor layer and the material element of the mirror can form an ohmic contact between the P-type semiconductor layer and the mirror, that is, the The mirror has good electrical contact with the P-type semiconductor layer, which can improve the luminous efficiency and meet the requirements for use.

The detailed description of the present invention and the technical description of the present invention are further illustrated by the accompanying drawings, but it should be understood that these embodiments are merely illustrative and not to be construed as limiting.

Referring to FIG. 3, which is an embodiment of the present invention, the present invention is a light-emitting diode having a good electrical contact mirror, which is applied to a light-emitting diode 100, and the light-emitting diode 100 includes An N-type electrode 10, an N-type semiconductor layer 20, a light-emitting layer 30, a P-type semiconductor layer 40, a mirror 50, a buffer layer 60, a bonding layer 70, a permanent substrate 80 and a P Type electrode 90.

Please refer to FIG. 4A and FIG. 4B together, wherein an intrinsic semiconductor layer 45 is disposed between the P-type semiconductor layer 40 and the mirror 50, and the P-type semiconductor is diffused from the intrinsic semiconductor layer 45. The doping element 41 of the layer 40 and the material element 51 of the mirror 50, wherein the intrinsic semiconductor layer 45 may be selected from indium gallium nitride (InGaN), and the doping element 41 of the P-type semiconductor layer 40 may be selected from magnesium (Mg The material element 51 of the mirror 50 may be silver (Ag).

The P-type semiconductor layer 40 may be gallium nitride (GaN) doped with magnesium (Mg), and include a first P-type semiconductor layer 401 and a second P-type semiconductor layer 402, and the first P-type semiconductor layer The atomic number of the 401-doped magnesium element is 1E18; and the number of atoms of the second P-type semiconductor layer 402 doped with the magnesium element is 1E20.

Further, a technical means for diffusing the doping element 41 of the P-type semiconductor layer 40 and the material element 51 of the mirror 50 to the intrinsic semiconductor layer 45 is used, and one of them may be selected by a high temperature tempering method, which allows the intrinsic semiconductor After the layer 45 and the mirror 50 are sequentially stacked on the P-type semiconductor layer 40, the temperature is raised to 500 ° C to 800 ° C by heating for 60 minutes (min), thus, the doping element of the P-type semiconductor layer 40 41 and the material element 51 of the mirror 50 are slowly diffused to the intrinsic semiconductor layer 45, and the intrinsic semiconductor layer 45 is diffused with the doping element 41 of the P-type semiconductor layer 40 and the material element of the mirror 50. 51 (as shown in Figure 4B).

The N-type semiconductor layer 20 may include a first N-type semiconductor layer 21 and a second N-type semiconductor layer 22, and the first N-type semiconductor layer 21 and the second N-type semiconductor layer 22 have different doping concentrations. To reduce defects in the process of crystal growth. And wherein the buffer layer 60 can be made of a group consisting of titanium, tungsten, platinum, nickel, aluminum and chromium, and has a relatively compact nature, can be used for blocking ion diffusion and avoiding ion diffusion during high temperature processing. Destroy other film structures while releasing stress as a stress buffer.

The bonding layer 70 may be made of any one selected from the group consisting of a gold-tin alloy, a gold-indium alloy, and a gold-lead alloy for bonding the buffer layer 60 and the permanent substrate 80. The permanent substrate 80 may be made of any one selected from the group consisting of a germanium substrate, a copper substrate, a copper tungsten substrate, an aluminum nitride substrate, and a titanium nitride substrate, and selects a material that has good heat dissipation and does not absorb light, and can reduce the temperature during light emission. And provide light extraction efficiency.

As described above, the present invention allows the intrinsic semiconductor layer 45 to be diffused with the doping element 41 of the P-type semiconductor layer 40 and the material element 51 of the mirror 50 to allow the intrinsic semiconductor layer 45 to be in the P-type. An ohmic contact is formed between the semiconductor layer 40 and the mirror 50, so that the contact resistance thereof can be greatly reduced, that is, the mirror 50 can be in good electrical contact with the P-type semiconductor layer 40, which can improve the luminous efficiency. And meet the needs of use.

The above are only the preferred embodiments of the present invention and are not intended to limit the scope of the embodiments of the present invention. That is, the equivalent changes and modifications made by the scope of the patent application of the present invention are covered by the scope of the invention.

Conventional knowledge

1. . . N-type semiconductor layer

1A. . . Irregular surface

2. . . Luminous layer

3. . . P-type semiconductor layer

3A. . . Nickel layer

4. . . Reflector

5. . . The buffer layer

6. . . Bonding layer

7. . .矽 substrate

8. . . P-type electrode

9. . . N-type electrode

this invention

100. . . Light-emitting diode

10. . . N-type electrode

20. . . N-type semiconductor layer

twenty one. . . First N-type semiconductor layer

twenty two. . . Second N-type semiconductor layer

30. . . Luminous layer

40. . . P-type semiconductor layer

401. . . First P-type semiconductor layer

402. . . Second P-type semiconductor layer

41. . . Doping element

45. . . Intrinsic semiconductor layer

50. . . Reflector

51. . . Material element

60. . . The buffer layer

70. . . Bonding layer

80. . . Permanent substrate

90. . . P-type electrode

FIG. 1 is a structural diagram of a conventional light emitting diode.
FIG. 2 is a structural diagram of another light-emitting diode.
Fig. 3 is a structural view of a diode of the present invention.
4A is a schematic view of the intrinsic semiconductor layer before diffusion according to the present invention.
4B is a schematic view showing the diffusion of the intrinsic semiconductor layer of the present invention.

100. . . Light-emitting diode

10. . . N-type electrode

20. . . N-type semiconductor layer

twenty one. . . First N-type semiconductor layer

twenty two. . . Second N-type semiconductor layer

30. . . Luminous layer

40. . . P-type semiconductor layer

401. . . First P-type semiconductor layer

402. . . Second P-type semiconductor layer

45. . . Intrinsic semiconductor layer

50. . . Reflector

60. . . The buffer layer

70. . . Bonding layer

80. . . Permanent substrate

90. . . P-type electrode

Claims (9)

A light-emitting diode with a good electrical contact mirror is applied to a light-emitting diode comprising an N-type electrode, an N-type semiconductor layer, a light-emitting layer and a P-type stacked in sequence a semiconductor layer, a mirror, a buffer layer, a bonding layer, a permanent substrate and a P-type electrode, wherein:
An intrinsic semiconductor layer is disposed between the P-type semiconductor layer and the mirror, and the intrinsic semiconductor layer diffuses a doping element of the P-type semiconductor layer and a material element of the mirror. A light-emitting diode having a good electrical contact mirror according to claim 1, wherein the P-type semiconductor layer is gallium nitride-doped magnesium, and the P-type semiconductor layer comprises a first P-type semiconductor layer and A second P-type semiconductor layer. A light-emitting diode having a good electrical contact mirror according to claim 2, wherein the first P-type semiconductor layer is doped with magnesium having an atomic number of 1E18, and the second P-type semiconductor layer is doped with magnesium The atomic number of the element is 1E20. A light-emitting diode having a good electrical contact mirror as claimed in claim 1 wherein the mirror uses silver. A light-emitting diode having a good electrical contact mirror according to claim 1, wherein the N-type semiconductor layer comprises a first N-type semiconductor layer and a second N-type semiconductor layer. A light-emitting diode having a good electrical contact mirror according to claim 1, wherein the buffer layer is made of a group selected from the group consisting of titanium, tungsten, platinum, nickel, aluminum and chromium. A light-emitting diode having a good electrical contact mirror according to claim 1, wherein the bonding layer is made of any one selected from the group consisting of a gold-tin alloy, a gold-indium alloy, and a gold-lead alloy. A light-emitting diode having a good electrical contact mirror according to claim 1, wherein the permanent substrate is any one selected from the group consisting of a germanium substrate, a copper substrate, a copper tungsten substrate, an aluminum nitride substrate, and a titanium nitride substrate. production. A light-emitting diode having a good electrical contact mirror according to claim 1, wherein the intrinsic semiconductor layer is indium gallium nitride, the doping element of the P-type semiconductor layer is magnesium, and the material of the mirror The element is silver.