KR101007092B1

KR101007092B1 - Semiconductor light emitting device and fabrication method thereof

Info

Publication number: KR101007092B1
Application number: KR1020080105256A
Authority: KR
Inventors: 정환희
Original assignee: 엘지이노텍 주식회사
Priority date: 2008-10-27
Filing date: 2008-10-27
Publication date: 2011-01-10
Also published as: KR20100046423A

Abstract

The embodiment relates to a semiconductor light emitting device and a method of manufacturing the same.

A semiconductor light emitting device according to the embodiment, the electrode layer; A light emitting structure including a second conductive semiconductor layer below the electrode layer, an active layer below the second conductive semiconductor layer, and a first conductive semiconductor layer below the active layer; A light emitting region protective layer electrically separating an inner region and an outer region of the active layer along a circumference under the electrode layer; It includes a reflective film formed on the outside of the light emitting structure.

Semiconductor, light emitting device

Description

Semiconductor light emitting device and method of manufacturing the same {Semiconductor light emitting device and fabrication method

Group III-V nitride semiconductors are spotlighted as core materials of light emitting devices such as light emitting diodes (LEDs) or laser diodes (LDs) due to their physical and chemical properties. The III-V nitride semiconductor is usually made of a semiconductor material having a composition formula of In _x Al _y Ga _1-xy N (0 ≦ x ≦ 1, 0 ≦ y ≦ 1, 0 ≦ x + y ≦ 1).

A light emitting diode (LED) is a kind of semiconductor device that transmits and receives a signal by converting electricity into infrared light or light using characteristics of a compound semiconductor.

LEDs or LDs using such nitride semiconductor materials are widely used in light emitting devices for obtaining light, and have been applied to light sources of various products such as keypad light emitting units, electronic displays, and lighting devices of mobile phones.

The embodiment provides a semiconductor light emitting device capable of reflecting light traveling toward sidewalls of a light emitting structure, and a method of manufacturing the same.

Embodiments provide a semiconductor light emitting device which electrically protects an inner region of a light emitting structure by electrically separating an inner region and an outer region of a light emitting structure, and forms a reflective film on an outer wall of the light emitting structure, thereby improving external quantum efficiency. It provides a manufacturing method.

A method of manufacturing a semiconductor light emitting device according to an embodiment may include forming a light emitting structure including a first conductive semiconductor layer, an active layer on the first conductive semiconductor layer, and a second conductive semiconductor layer on the active layer; Forming a light emitting region protective layer between an inner region and an outer region of the light emitting structure along an outer side of the second conductive semiconductor layer; Forming an electrode layer on an inner region over the second conductive semiconductor layer; Forming a reflective film on an outer wall of the light emitting structure.

Embodiments can provide a moisture resistant LED.

According to the embodiment, the oxide film material is formed between the nitride semiconductor layer and the electrode layer, thereby enhancing the adhesion between the nitride semiconductor layer and the electrode layer.

According to the embodiment, the outer wall of the light emitting structure may be electrically separated from the inner region, and a reflective film may be formed on the outer wall to improve the external quantum efficiency.

The embodiment can improve the electrical reliability by disposing the light emitting structure of the light emitting structure in the inner region.

Hereinafter, exemplary embodiments will be described with reference to the accompanying drawings. Hereinafter, in describing the embodiments, the above or below of each layer will be described with reference to the drawings.

1 is a side cross-sectional view illustrating a semiconductor light emitting device according to a first embodiment.

Referring to FIG. 1, the semiconductor light emitting device 100 may include a light emitting structure 135, a light emitting area protection layer 140, an electrode layer 150, a conductive support member 160, and a reflective film 180.

The light emitting structure 135 includes a first conductive semiconductor layer 110, an active layer 120, and a second conductive semiconductor layer 130. In addition, an n-type semiconductor layer or a p-type semiconductor layer may be formed on the light emitting structure 135 on the second conductive semiconductor layer 130.

The first conductive semiconductor layer 110 may be implemented as an n-type semiconductor layer, and the n-type semiconductor layer may be formed of any one of compound semiconductors such as GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, and the like. , n-type dopants (eg, Si, Ge, Sn, Se, Te, etc.) are doped.

The first electrode 171 may be formed in a predetermined pattern under the first conductive semiconductor layer 110.

An active layer 120 is formed on the first conductive semiconductor layer 110, and the active layer 120 is formed in a single or multiple quantum well structure, for example, with an InGaN well layer / GaN barrier layer as one cycle. It can be formed into single or multiple quantum well structures. The material of the quantum well layer and the quantum barrier layer may vary depending on the light emitting material, but the active layer 120 is not limited thereto. A clad layer may be formed on or under the active layer 120.

A second conductive semiconductor layer 130 is formed on the active layer 120, and the second conductive semiconductor layer 130 may be implemented as a p-type semiconductor layer doped with a p-type dopant. The p-type semiconductor layer may be formed of any one of compound semiconductors such as GaN, InN, AlN, InGaN, AlGaN, InAlGaN, AlInN, and the like. The p-type dopant includes an element series such as Mg, Be, and Zn.

Alternatively, in the light emitting structure 135, the first conductive semiconductor layer 110 may be a p-type semiconductor layer, and the second conductive semiconductor layer 130 may be an n-type semiconductor layer. Here, a third conductive semiconductor layer may be formed on the second conductive semiconductor layer 130, and the third conductive semiconductor layer may be a p-type semiconductor layer when the second conductive semiconductor layer is an n-type semiconductor layer. The p-type semiconductor layer may be formed as an n-type semiconductor layer. That is, the light emitting structure 135 may include at least one of np junction, pn junction, npn junction, and pnp junction structure.

The emission region protection layer 140 and the electrode layer 150 are formed on the second conductive semiconductor layer 130.

The emission area protection layer 140 is formed on the outer side of the second conductive semiconductor layer 130, and the electrode layer 150 is formed on the inner side of the second conductive semiconductor layer 130. In addition, the electrode layer 150 may be formed to extend on the emission area protection layer 140.

The emission region protection layer 140 may be formed of an insulating material, for example, may be selectively formed of SiO ₂ , SiO _x , SiO _x N _y , Si ₃ N ₄ , Al ₂ O ₃ , TiO _{2, or the} like.

The emission area protection layer 140 may improve the adhesion between the second conductive semiconductor layer 130 and the electrode layer 150. The emission area protection layer 140 may have a thickness of about 0.1 μm to about 2 μm, but is not limited thereto.

An area protection protrusion 145 is formed on the emission area protection layer 140. The area protection protrusion 145 is formed in a closed loop shape by being spaced apart by a predetermined distance along the outer wall of the light emitting structure 135 to form the light emitting structure 135 in the first area A1 and the second area A2. To separate. The area protection protrusions 145 of the light emitting area protection layer 140 are formed to be spaced apart from the outer wall of the light emitting structure 135 by a predetermined distance D. The distance D may be formed, for example, in a range of 1 to 5 μm, and may be changed according to the size of the light emitting structure 135.

The region protection protrusion 145 communicates with the upper portion of the second conductive semiconductor layer 130, the active layer 120, and the first conductive semiconductor layer 110 and has a closed loop shape (FIG. 3, 115).

The thickness T of the area protection protrusion 145 may be formed from the second conductive semiconductor layer 130 to a part of the first conductive semiconductor layer 110. The area protection protrusion 145 may be formed in a band shape in the form of a plurality of bands or a zigzag shape, and the like, and is not limited thereto.

The area protection protrusion 145 of the emission area protection layer 140 electrically separates the first area A1 from the second area A2, and the emission area protection layer 140 is the electrode layer 140. ) And the second conductive semiconductor layer 130 are electrically separated from each other. Accordingly, the emission region protection layer 140 may open the electrical characteristics of the semiconductor layer positioned in the second region A2.

The area protection protrusion 145 of the emission area protection layer 140 has a band shape between the first area A1 and the second area A2 and is formed in a closed loop, thereby forming the semiconductor layer of the second area A2. Are not activated even when power is supplied.

A width W of the area protection protrusion 145, that is, a bottom width thereof may be formed to be 1 μm to 10 μm. The critical criterion of the width W may be formed over a minimum interval without electrical interference between the active layers of the two regions A1 and A2.

The electrode layer 150 may be formed on the second conductive semiconductor layer 130, or may be formed on the second conductive semiconductor layer 130 and the emission area protection layer 140. The electrode layer 150 may be formed of at least one or alloys thereof such as Al, Ag, Pd, Rh, and Pt for ohmic properties, reflective properties, and seed metals. In addition, the electrode layer 150 may be formed of an electrode material having ohmic characteristics.

The conductive support member 160 is formed on the electrode layer 150. The conductive support member 160 may be formed of a material such as copper, gold, a carrier wafer (eg, Si, Ge, GaAs, ZnO, SiC, etc.) as a base substrate. The electrode layer 150 and the conductive support member 160 may be integrally formed. For example, the electrode layer 150 and the conductive support member 160 may be formed to a predetermined thickness by using a metal having good reflection and ohmic characteristics.

Since the light emitting structure 135 emits light in the first region A1 and the second region A2 is electrically open, the light emitting structure 135 is not activated. In addition, since the outer region of the light emitting structure 135 is electrically opened, the inner first region A1 may be protected from a short problem caused by moisture in the outer wall of the light emitting structure 135.

In addition, there is an effect that it is not necessary to form a separate insulating layer on the outer wall of the light emitting structure 135.

The protrusion 165 generated during the laser scribing process may protrude to the outside of the light emitting structure 135 on the outside of the conductive support member 160. When the protrusion 165 is formed of a material such as copper, there is a problem of absorbing light emitted from the light emitting structure 135 to the sidewall. Accordingly, the embodiment forms the reflective film 180 on the sidewall of the light emitting structure 135. The reflective film 180 may include a material such as a high reflection material such as Al, Ag, and one end 182 may be formed on an outer surface of the first conductive semiconductor layer 110, and the other end 181 may be formed. It is formed on a portion of the light emitting area protective layer 140. Accordingly, the entire outer surface of the light emitting structure 135 is covered by the reflective film 180, so that even if a part of the light emitted by the light emitting structure 135 travels toward the sidewall, the light is reflected by the reflective film 180. As a result, the external quantum efficiency can be improved. According to an embodiment, the reflective film 180 may be formed on at least one sidewall of the light emitting structure 135, or may be formed between the outer wall of the light emitting structure 135 and the protruding portion of the conductive support member 160.

2 to 9 illustrate a process of manufacturing a semiconductor light emitting device according to the first embodiment.

2 and 3, a first conductive semiconductor layer 110 is formed on the substrate 101, an active layer 120 is formed on the first conductive semiconductor layer 110, and the active layer 120 is formed on the substrate 101. ), A second conductive semiconductor layer 130 is formed.

The substrate 101 may be selected from the group consisting of sapphire substrate (Al ₂ O ₃ ), GaN, SiC, ZnO, Si, GaP, InP, and GaAs. A buffer layer and / or an undoped semiconductor layer may be formed on the substrate 101, and may be removed after the thin film is grown.

The first conductive semiconductor layer 110 may be an n-type semiconductor layer, the second conductive semiconductor layer 130 may be a p-type semiconductor layer, and the n-type semiconductor layer may be GaN, InN, AlN, InGaN. , AlGaN, InAlGaN, AlInN, or any one of compound semiconductors, and an n-type dopant (eg, Si, Ge, Sn, Se, Te, etc.) is doped. The p-type semiconductor layer may be doped with a p-type dopant such as Mg, and may be formed of any one of compound semiconductors such as GaN, InN, AlN, InGaN, AlGaN, InAlGaN, and AlInN.

Other semiconductor layers may be formed on or under the first conductive semiconductor layer 110, the active layer 120, and the second conductive semiconductor layer 130, but embodiments are not limited thereto. The first conductive semiconductor layer 110, the active layer 120, and the second conductive semiconductor layer 130 may be defined as a light emitting structure 135. In addition, the light emitting structure 135 may include at least one of np junction, pn junction, npn junction, and pnp junction structure.

Referring to FIG. 3, an area separation groove 115 may be formed at an outer circumference of the second conductive semiconductor layer 130 to a part of the first conductive semiconductor layer 110.

The region separation groove 115 may have a band shape along an outer circumference of the light emitting structure 135 and may be formed as a closed loop. The thickness T or the depth of the region isolation groove 115 is formed such that a part of the first conductive semiconductor layer 110 is exposed in the second conductive semiconductor layer 130.

Here, the band shape of the region separation groove 115 is changeable, the cross-sectional shape may be formed in a polygonal shape such as hemispherical shape, semi-elliptical shape, inverted horn shape, columnar shape, square or rhombus or trapezoidal shape. However, these shapes can be changed. The region separation groove 115 may be formed in one or a plurality of band shapes, and may be formed in a straight shape or a zigzag shape, but is not limited thereto.

The region separation groove 115 may be formed through a wet or / and dry etching process, but is not limited thereto.

The region isolation groove 115 is formed in a rectangular frame shape by being spaced inward from the outer wall of the second conductive semiconductor layer 130 at predetermined intervals, and the first conductive semiconductor layer 110 is formed at the center thereof. Exposed.

The region separation groove 115 is spaced apart from the first side wall of the light emitting structure 135 by a predetermined distance D, for example, in a range of 1 to 5 μm, and a bottom width W thereof is defined by the first conductive semiconductor layer ( 110 is a width exposed, it may be formed to 1 ~ 10㎛.

The outer shape of the region separation groove 115 may be formed in a polygonal shape such as a circle or an oval, a triangle, and a rectangle, as well as a rectangular frame shape, and the shape may be changed. The inner side of the region separation groove 115 may be a substantially light emitting region. That is, the region separation groove 115 bisects the first region A1 and the second region A2 and electrically opens the outer wall of the light emitting structure 135.

Referring to FIG. 4, a light emitting area protection layer 140 is formed on an outer circumference of the second conductive semiconductor layer 130. In this case, an area protection protrusion 145 of the emission area protection layer 140 is formed in the area separation groove 115.

The area protection protrusion 145 of the emission area protection layer 140 separates the second conductive semiconductor layer 130 and the active layer 120 of the first area A1 and the second area A2 from each other. .

The area protection protrusion 145 causes the first area A1 to be inside the light emitting structure 135 and the second area A2 to be outside the light emitting structure 135.

5 and 6, an electrode layer 150 is formed on the second conductive semiconductor layer 130. In addition, the electrode layer 150 may be formed on the emission area protection layer 140. The conductive support member 160 is formed on the electrode layer 150.

The electrode layer 150 may be formed of at least one of Al, Ag, Pd, Rh, Pt, or an alloy. A conductive support member 160 is formed on the electrode layer 150, and the conductive support member 160 may be formed of copper, gold, carrier wafers (Si, Ge, GaAs, ZnO, etc.), and may be formed as a base substrate. Function. The electrode layer 150 and the conductive support member 160 may be formed of one layer, for example, a reflective electrode support member, but are not limited thereto.

6 and 7, the substrate 101 is removed. The substrate 101 may be removed by a laser lift off (LLO) process. That is, the substrate 101 is separated by a method of irradiating a laser having a wavelength of a predetermined region to the substrate 101 (LLO: Laser Lift Off). Alternatively, when another semiconductor layer (eg, a buffer layer) is formed between the substrate 101 and the first conductive semiconductor layer 110, the substrate may be separated by using a wet etching solution to remove the buffer layer. The surface of the first conductive semiconductor layer 110 from which the substrate 101 is removed may be polished by an inductively coupled plasma / reactive ion etching (ICP / RIE) method.

8 and 9, the light emitting structure 135 is removed by mesa etching (eg, using ICP equipment) for the chip and the chip boundary region (ie, the channel region). The mesa etching region 105 may be formed to the extent that the emission region protection layer 140 is exposed in the chip boundary region, but is not limited thereto.

When the chip boundary region 105 is exposed, the reflective film 180 is formed on at least one outer wall of the outer wall of the light emitting structure 135. Since the reflective film 180 is formed on the outer wall of the light emitting structure 135, that is, the outer wall of the electrically opened semiconductor layers, the short-circuit problem does not have to be considered and reflects light traveling to the side wall.

One end 182 of the reflective film 180 is formed outside the surface of the first conductive semiconductor layer 110, and the other end 181 is formed on the surface of the emission region protection layer 140. It can strengthen the adhesion.

Referring to FIG. 9, a chip unit may be separated along the chip boundary region 150. In this case, the chip separation method may be used as a laser. When the laser is separated by a chip unit, an outer portion of the conductive support member 160 on which the laser is focused may protrude to a predetermined height below the outside of the light emitting structure 135 in the form of a protrusion 165. have. Since the protrusion 165 absorbs light because the protrusion 165 is made of a material such as copper, the protrusion 165 reflects the light traveling from the light emitting structure 135 to the outer wall by the reflective film 180.

The embodiment is not limited to the protrusion 165 of the conductive support member 160, and the reflective film 180 is not formed on the outer wall of the light emitting structure 135, and the reflective film is formed on the inner circumference of the protrusion 165. May be formed.

The first electrode 171 is formed in a predetermined pattern under the first conductive semiconductor layer 110.

In the semiconductor light emitting device 100, the second conductive semiconductor layer 130 and the active layer 120 of the first region A1 are electrically connected to the second conductive semiconductor layer and the active layer of the second region A2. Since it is separated, even if the outer wall of the light emitting structure 135 is in contact with moisture, the short does not occur with each other, and does not affect the first region.

In addition, even when moisture penetrates through the outer wall of the light emitting structure 135, the area protection protrusion 145 of the light emitting area protection layer 140 may block moisture from the inside of the outer wall, thereby providing a high humidity resistant LED. Can be.

In addition, by reflecting the light emitted to the outer wall of the light emitting structure 135 to the reflective film around the inner surface of the projection of the reflective film 180 or / and the conductive support member 160, it is possible to improve the external quantum efficiency.

10 is a view showing a semiconductor light emitting device according to the second embodiment. In the description of the second embodiment, the same parts as in the first embodiment will be denoted by the same reference numerals and redundant description thereof will be omitted.

Referring to FIG. 10, the semiconductor light emitting device 100A includes a light emitting area protection layer 140 between an outer side of the second conductive semiconductor layer 130 and an electrode layer 150.

The emission area protection layer 140 is made of an insulating material, and an area protection protrusion 145A is formed on the lower outer side.

The area protection protrusion 145A is formed from the second conductive semiconductor layer 130 to a portion outside of the active layer 120 and the first conductive semiconductor layer 110. The area protection protrusion 145A of the light emitting area protection layer 140 may be formed to have a predetermined width from the outside to the inside of the light emitting structure 135, even if moisture is contacted with the outer wall of the light emitting structure 135. You can protect the area. In addition, the second embodiment may provide a larger first area than the first embodiment.

In describing the above embodiments, each layer, region, pattern, or structure may be placed on or under a substrate, each layer, region, pad, or pattern. When described as being formed, "on" and "under" include both the meanings of "directly" and "indirectly". In addition, the criteria for the top or bottom of each layer will be described with reference to the drawings.

The present invention has been described above with reference to preferred embodiments thereof, which are merely examples and are not intended to limit the present invention. Those skilled in the art to which the present invention pertains do not depart from the essential characteristics of the present invention. It will be appreciated that various modifications and applications are not possible that are not illustrated above. For example, each component shown in detail in the embodiment of the present invention may be modified. And differences relating to such modifications and applications will have to be construed as being included in the scope of the invention defined in the appended claims.

1 is a side sectional view showing a semiconductor light emitting device according to the first embodiment;

2 to 9 are views illustrating a manufacturing process of the semiconductor light emitting device of FIG. 1.

10 is a side sectional view showing a semiconductor light emitting device according to the second embodiment;

Claims

An electrode layer;

A light emitting structure including a second conductive semiconductor layer on the electrode layer, an active layer on the second conductive semiconductor layer, and a first conductive semiconductor layer on the active layer;

A protective layer disposed along a circumference between the electrode layer and the light emitting structure to electrically separate an inner region and an outer region of the active layer; And

A semiconductor light emitting device comprising a reflective film formed on the outside of the light emitting structure.

The method of claim 1,

The protective layer is formed of an insulating material, and includes a protrusion extending from the second conductive semiconductor layer of the light emitting structure to a lower portion of the first conductive semiconductor layer to separate the inner and outer regions of the active layer. Semiconductor light emitting device.

The method according to claim 1 or 2,

The protective layer and the protrusion of the protective layer comprises a closed loop form.

The method according to claim 1 or 2,

An inner region of the active layer is a light emitting region,

And an outer region of the active layer is an inactive region.

The method of claim 2,

And an outer region of the active layer is disposed between the protrusion of the protective layer and the reflective film.

The method of claim 1,

The reflective film includes a metal material and is formed on at least one side of the light emitting structure.

3. The method of claim 2,

The protrusion of the protective layer is a semiconductor light emitting device having a lower width than the upper width.

The method of claim 2,

The projection of the protective layer is a semiconductor light emitting device disposed within 5㎛ relative to the outside of the light emitting structure.

The method of claim 2,

The projection of the protective layer is a semiconductor light emitting device that is in contact with the lower portion of the first conductive semiconductor layer in a width of 1 ~ 10㎛.

The method of claim 2,

The protective layer includes at least one of SiO ₂ , SiO _x , SiO _x N _y , Si ₃ N ₄ , Al ₂ O ₃ , or TiO ₂ .

The method of claim 2,

The cross-sectional shape of the projection of the protective layer is a semiconductor light emitting device comprising any shape of hemispherical, semi-oval, polygonal, inverted horn, columnar shape.

The method of claim 6,

The reflective film extends from all sides of the light emitting structure to the upper periphery.

The method of claim 1,

A semiconductor light emitting device comprising a conductive support member formed under the electrode layer.

Conductive support members;

An electrode layer on the conductive support member;

A protective layer formed around the electrode layer and the second conductive semiconductor layer; And

It includes a reflective film formed on the outside of the light emitting structure,

The protective layer includes at least one protrusion protruding from the second conductive semiconductor layer to a lower portion of the first conductive semiconductor layer.

The method of claim 14,

The protective layer and the projection is an insulating material,

The reflective film is a semiconductor light emitting device comprising a metal material containing at least one of Al or Ag.

The method of claim 14,

The protrusion of the protective layer extends from the lower portion of the first conductive semiconductor layer to the reflective film.

The method of claim 14,

The reflective film is a semiconductor light emitting device formed on the side of the first conductive semiconductor layer of the light emitting structure.

The method of claim 17,

The reflective film extends to the periphery of the upper surface of the first conductive semiconductor layer.

The method according to claim 1 or 14, wherein

A semiconductor light emitting device comprising an electrode electrically connected to the first conductive semiconductor layer.