KR20140037482A - Light emitting device - Google Patents

Abstract

The present invention includes a first semiconductor layer, an activating layer located on the first semiconductor layer to emit light, and a second semiconductor layer located on the activating layer, wherein at least one semiconductor layer among the first semiconductor layer and the second semiconductor layer includes an ALxGaNy. The present invention relates to a light emitting device having at least 40% of a ratio of GaN to Al and transmitting light having a wavelength of less than and equal to 300nm.

Description

[0001] LIGHT EMITTING DEVICE [0002]

An embodiment relates to a light emitting element.

Light emitting diodes (LEDs) are a type of semiconductor devices that convert electrical energy into light. Light emitting diodes have advantages of low power consumption, semi-permanent lifetime, fast response speed, safety, and environmental friendliness compared with conventional light sources such as fluorescent lamps and incandescent lamps. Therefore, much research is underway to replace an existing light source with a light emitting diode. In addition, a light emitting device using a light emitting diode is widely used as a light source for lighting devices such as various liquid crystal display devices, electronic displays, and street lamps that are used indoors and outdoors.

Light emitting devices are classified into horizontally structured light emitting devices and vertically structured light emitting devices. Light emitting devices having a horizontal structure may be classified into a top-emitting light emitting device and a flip-chip light emitting device.

The top-emit light emitting device is formed such that light is emitted through an electrode layer in contact with the p-type semiconductor layer, and the flip chip light emitting device is formed so that light is emitted through a sapphire substrate. Flip chip type light emitting devices are generally die attached onto a submount (or package or lead frame: hereinafter referred to as a 'submount'), and light is extracted to attach one side of the light emitting device that is not die attached to the submount. Can diverge through.

Another object of the present invention is to provide a light emitting device chip having a high light transmittance.

Another object of the present invention is to provide a light emitting device chip having high light efficiency.

In one embodiment, the light emitting device includes a first semiconductor layer, an active layer disposed on the first semiconductor layer and emitting light, and a second semiconductor layer disposed on the active layer, the first semiconductor layer and the second semiconductor layer At least one semiconductor layer of the layer comprises ALxGaNy, wherein the ratio of Al to GaN is at least 40% and relates to the transmission of light having a wavelength of 300 nm or less.

In one embodiment, the light emitting device is a first semiconductor layer comprising ALxGaNy, an active layer disposed on the first semiconductor layer and emitting light, a second semiconductor layer and a second semiconductor layer disposed on the active layer and comprising ALxGaNy And a transparent electrode disposed on and including gallium oxide (GaxOy), wherein the second semiconductor layer is divided into a plurality of layers having different ratios of Al to GaN, and the ratio of Al to GaN of the plurality of layers is at least 40. The ratio of% relates to the arrangement of the transparent electrode on one layer having.

According to the embodiment, the light emitting device may transmit light of 300 nm or less. The light efficiency can be increased by reflecting the light transmitted through the reflector. Further, the current-voltage characteristics of the light-emitting element can be improved.

1 is a cross-sectional view showing a first embodiment of a light emitting diode.
2 is a sectional view showing a second embodiment of the light emitting diode.
3 is a cross-sectional view showing a third embodiment of the light emitting diode.
4 is a cross-sectional view showing the structure of a flip chip type light emitting device employing a light emitting diode according to an embodiment.
5 is a cross-sectional view showing the structure of a horizontal light emitting device employing a light emitting diode according to the embodiment.
6 is a cross-sectional view showing the structure of a vertical light emitting device employing the light emitting diode according to the embodiment.
7 is a cross-sectional view of a light emitting device package according to the embodiment.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. It is to be understood, however, that the appended drawings illustrate the present invention in order to more easily explain the present invention, and the scope of the present invention is not limited thereto. You will know.

In addition, the upper or lower reference of each component is described with reference to the drawings. The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size of each component does not entirely reflect the actual size.

The thickness and size of each layer in the drawings are exaggerated, omitted, or schematically shown for convenience and clarity of explanation. Also, the size of each component does not entirely reflect the actual size.

In the description of the embodiment according to the present invention, when described as being disposed on an "on or under" of each element, the above (up) or down (below) On or under includes both elements in direct contact with one another or one or more other elements indirectly disposed between the two elements. In addition, when expressed as "on" or "under", it may include the meaning of the downward direction as well as the upward direction based on one element.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

1 is a cross-sectional view showing a first embodiment of a light emitting diode.

Referring to FIG. 1, the light emitting diode 100a may include a substrate 100, a buffer layer 110 disposed on the substrate 100, a first semiconductor layer 120 disposed on the buffer layer 110, and a first semiconductor layer. The active layer 130 disposed on the 120 and the second semiconductor layer 140 disposed on the active layer 130 are included.

The substrate 100 is suitable for growing a semiconductor single crystal, and may be disposed using a transparent material including, for example, sapphire. In addition to the sapphire, the substrate 100 may be disposed using zinc oxide (ZnO), gallium nitride (GaN), silicon carbide (SiC), and aluminum nitride (AlN). have.

The buffer layer 110 is formed on the substrate 100 and is a layer for improving lattice matching with the substrate 100 before growing the first semiconductor layer 120, and may be omitted according to process conditions and device characteristics. have.

The first semiconductor layer 120 may be formed by growing on the buffer layer 110. The first semiconductor layer 120 may be formed of an n-type semiconductor doped with n-type conductive impurities. As the n-type conductivity type impurity, for example, Si, Ge, Sn or the like can be used, and preferably Si is mainly used. The first semiconductor layer 120 may include Al x GaNy (where 0 = X, 0 = Y, and X + Y = 1). As a result, the first semiconductor layer 120 may transmit light having a wavelength of 300 nm or less.

The active layer 130 may be formed of an InGaN / GaN layer having a multi-quantum well structure. The active layer 130 may emit light having a wavelength of 300 nm or less. The active layer 130 generally includes a quantum well layer and a barrier layer. Here, the order of stacking the barrier layer and the quantum well layer is not specifically defined. However, the order of stacking the barrier layer and the quantum well layer may be laminated from the quantum well layer to the quantum well layer, or may be laminated from the quantum well layer to the barrier layer. In addition, the barrier layer may be laminated from the barrier layer to the barrier layer, or may be laminated from the barrier layer to the quantum well layer.

The second semiconductor layer 140 may be formed by growing on the active layer 130. The second semiconductor layer 140 may be formed of a p-type semiconductor doped with a p-type conductive impurity. As the p-type conductive impurity, for example, Mg, Zn, Be or the like can be used, and preferably Mg is mainly used. The second semiconductor layer 140 may include a plurality of layers. For convenience of explanation, it is assumed that the second semiconductor layer 140 is composed of two layers 141 and 142. The first second semiconductor layer 141 formed on the active layer 130 among the second semiconductor layers 140 including a plurality of layers may include AlxGaNy (where 0 = X, 0 = Y, and X + Y = 1). And the second second semiconductor layer 142 in contact with the electrode may be comprised of GaN. When the second second semiconductor layer 142 is formed of GaN, an electrode (not shown) in contact with the second second semiconductor layer 142 and the second semiconductor layer 142 is in ohmic contact. Current voltage characteristics between the semiconductor layer 142 and the electrodes of the light emitting diode 100a may be improved. However, since the second second semiconductor layer 142 is made of GaN, the light emitting diodes 100a may absorb light (eg, ultraviolet rays) having a wavelength of 300 nm or less from the second second semiconductor layer 142. . Therefore, only light irradiated in the sapphire direction from the active layer 130 may be used.

2 is a cross-sectional view showing a second embodiment of the light emitting diode, and FIG. 3 is a cross-sectional view showing a third embodiment of the light emitting diode.

2 and 3, the light emitting diodes 200a and 200b may include a substrate 200, a buffer layer 210 disposed on the substrate 200, and a first semiconductor layer 220 disposed on the buffer layer 210. , An active layer 230 disposed on the first semiconductor layer 220, and a second semiconductor layer 240 disposed on the active layer 230. In this case, the substrates 200a and 200b, the buffer layer 210, the first semiconductor layer 220, and the active layer 230 may be disposed as shown in FIG. 1, and thus description thereof is omitted. Here, the upper portion of the active layer 230 is omitted. Next, the layers formed on the substrate will be described.

The second semiconductor layer 240 may be formed by growing on the active layer 230. The second semiconductor layer 240 may be formed of a p-type semiconductor doped with a p-type conductive impurity. As the p-type conductive impurity, for example, Mg, Zn, Be or the like can be used, and preferably Mg is mainly used. The second semiconductor layer 240 may include AlxGaNy (where 0 = X, 0 = Y, and X + Y = 1). As a result, the second semiconductor layer 240 may transmit light having a wavelength of 300 nm or less. In addition, the second semiconductor layer 240 may be stacked with a plurality of layers 241 and 242. The second semiconductor layer 242 formed on the outer side of the second semiconductor layer 240 formed of a plurality of layers may be in contact with an electrode (not shown) to receive a voltage from the electrode. When the second semiconductor layer 240 is stacked in a plurality of layers, AlxGaNy included in each layer may have a different ratio. In an embodiment, the second semiconductor layer 242 in contact with the electrode among the plurality of layers of the second semiconductor layer 240 may have a ratio of Al to GaN of at least 40%.

In addition, as illustrated in FIG. 3, the transparent electrode 250 is disposed on the second semiconductor layer 242 formed on the outer side of the second semiconductor layer 240, and the transparent electrode 250 is disposed on the transparent electrode 250. The reflective plate 260 reflecting the light passing through the 250 may be disposed. At this time, the transparent electrode 250 may include gallium oxide (GaxOy), the ratio of gallium (Ga) and oxygen (O) in the gallium oxide is 1: 1, 1: 2 :, 1: 3 :, 2: 1: It may be any one of the ratio of 2; 2,2: 3. Light passing through the transparent electrode 250 may be irradiated toward the substrate 200 by the reflector 260. As a result, the light efficiency of the light emitting diode can be increased.

In FIG. 3, light of 300 nm passing through the transparent electrode is reflected through the reflecting plate 260 to increase light efficiency. However, the present invention is not limited thereto, and the reflecting plate 260 is not used without using the transparent electrode 250. ) May be used as a conductive material. The conductive reflector 260 may be formed of at least one of silver (Ag) having a high reflectance, an alloy containing silver (Ag), aluminum (Al), or an alloy containing aluminum (Al).

4 is a cross-sectional view showing the structure of a flip chip type light emitting device employing a light emitting diode according to an embodiment.

Referring to FIG. 4, the light emitting device 400a includes a substrate 400, a buffer layer 410 disposed on the substrate 400, a first semiconductor layer 420 disposed on the buffer layer 410, and an active layer 430. ), A second semiconductor layer 440, a transparent electrode 450 disposed on the second semiconductor layer 440, and a reflecting plate 460 disposed on the transparent electrode 450. In addition, the light emitting device 400a includes a first under metallization (UBM) layer 470 disposed on the reflector 460 and a second base metal (UBM) layer disposed on the second electrode 435. 435, a submount substrate 500, a first electrode pad 490, a passivation layer 475, and a first electrode pad disposed in a predetermined area on the submount substrate 500, respectively. A third base metal (UBM) layer 480 disposed on 490, a first solder bumper 460 disposed between the first and third base metal (UBM) layers 470, 480, protection Second electrode pad 465 disposed on passivation layer 475, fourth base metal (UBM) layer 455, second and fourth base metal disposed on second electrode pad 465. And a second solder bumper 445 disposed between the (UBM) layers 435 and 455.

Accordingly, the light emitting device 400a may reflect light by the reflecting plate 460 to irradiate light toward the substrate 500.

FIG. 5 is a view illustrating a horizontal light emitting device employing a light emitting diode according to an exemplary embodiment.

The horizontal light emitting device 500a illustrated in FIG. 5 may be implemented by exposing a portion of the first semiconductor layer 520 and forming a first electrode 900a on the exposed first semiconductor layer 520. have.

The transparent electrode 550 may be formed on the second semiconductor layer 540. The transparent electrode 550 may include GaxOy to make ohmic contact with the second semiconductor layer 542 including ALxGaNy formed on the outer side of the second semiconductor layer 540.

6 is a view applied to a vertical light emitting device employing the light emitting diode according to the embodiment.

Referring to FIG. 6, in the vertical light emitting device 600a, a reflective plate 660 and a conductive support member 670 are formed on the second semiconductor layer 640, and the substrates 100 and 200 shown in FIGS. ) Can be removed.

The reflective plate 660 may be formed on the second semiconductor layer 660. The reflector plate 660 may be formed of silver (Ag), an alloy containing silver (Ag), an alloy containing aluminum (Al), aluminum (Al), platinum (Pt), or an alloy containing platinum (Pt). It may be formed of at least one.

The conductive support member 670 may be formed on the reflector plate 660. The conductive support member 670 provides power to the vertical light emitting device.

The conductive support member 670 is titanium (Ti), chromium (Cr), nickel (Ni), aluminum (Al), platinum (Pt), gold (Au), tungsten (W), copper (Cu), molybdenum (Mo) ) Or at least one of a semiconductor substrate into which impurities are implanted.

Meanwhile, a transparent electrode 650 including GaxOy may be formed between the two layers between the conductive support member 670 and the reflecting plate 670 for ohmic contact between the two layers.

The substrates 100 and 200 illustrated in FIGS. 1 to 3 may be removed by a laser lift off (LLO) process or may be removed by an etching process, but are not limited thereto.

After removing the substrates 100 and 200, portions of the buffer layers 110 and 210 and the first semiconductor layers 120 and 220 may be removed by an etching process, for example, inductively coupled plasma / reactive ion etching (ICP / RIE). It is not limited.

After the substrates 100 and 200 are removed, an electrode 610 may be formed on any one of the exposed first semiconductor layers 120 and 220 and the buffer layers 110 and 210. In FIG. 6, the electrode 610 contacts the first semiconductor layer 620 exposed by removing the buffer layer, so that the electrode 610 together with the conductive support member 670 provides power to the vertical light emitting device according to the embodiment. .

7 is a cross-sectional view of a light emitting device package according to the embodiment.

Referring to FIG. 7, the light emitting device package according to the embodiment may be installed on the package body 1000 and the first electrode layer 2000, the second electrode layer 3000, and the package body 1000 formed on the package body 1000. The light emitting device 4000 may be electrically connected to the first electrode layer 2000 and the second electrode layer 3000, and the filling material 5000 may be embedded in the light emitting device 4000.

The package body 1000 may include a silicon material, a synthetic resin material, or a metal material, and may have an inclined surface formed around the light emitting device 4000. The inclined surface may increase the light extraction efficiency of the light emitting device package.

The first electrode layer 2000 and the second electrode layer 3000 are electrically separated from each other, and provide power to the light emitting device 4000. In addition, the first electrode layer 2000 and the second electrode layer 3000 may increase light efficiency by reflecting light generated from the light emitting device 4000, and discharge heat generated from the light emitting device 4000 to the outside. Can play a role.

The light emitting device 4000 may be disposed on the package body 1000 or may be disposed on the first electrode layer 2000 or the second electrode layer 3000. The light emitting device 4000 may be electrically connected to the first electrode layer 2000 and the second electrode layer 3000 by any one of a wire method, a flip chip method, or a die bonding method.

The light emitting device 4000 may be any one of the light emitting devices shown in FIGS. 4 to 6. Therefore, the light emitting device 4000 may emit light in the ultraviolet region. For example, the light emitting device 4000 may emit light within a range of 300 nm or less.

Filler 5000 is embedded to protect the light emitting device (4000). In addition, the filler 5000 may include a phosphor to change the wavelength of light emitted from the light emitting device 4000.

The light emitting device package illustrated in FIG. 7 may mount at least one of the light emitting devices of the above-described embodiments as one or more, but is not limited thereto.

A plurality of light emitting device packages according to the embodiment may be arranged on a substrate, and a light guide plate, a prism sheet, a diffusion sheet, or the like, which is an optical member, may be disposed on an optical path of the light emitting device package. Such a light emitting device package, a substrate, and an optical member can function as a light unit. Still another embodiment may be implemented as a display device, an indicating device, a lighting system including the semiconductor light emitting device or the light emitting device package described in the above embodiments, for example, the lighting system may include a lamp, a streetlight .

The features, structures, effects and the like described in the embodiments are included in one embodiment of the present invention and are not necessarily limited to only one embodiment. Furthermore, the features, structures, effects and the like illustrated in the embodiments can be combined and modified by other persons skilled in the art to which the embodiments belong. Therefore, it should be understood that the present invention is not limited to these combinations and modifications.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of illustration, It can be seen that various modifications and applications are possible. For example, each component specifically shown in the embodiments can be modified and implemented. It is to be understood that all changes and modifications that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

200: substrate 210: buffer layer
220: first semiconductor layer 230: active layer
241, 242, 240: second semiconductor layer 250: transparent electrode
260: reflector

Claims (7)

A first semiconductor layer;
An active layer disposed on the first semiconductor layer and emitting light; And
A second semiconductor layer disposed on the active layer,
At least one semiconductor layer of the first semiconductor layer and the second semiconductor layer comprises ALxGaNy, the ratio of Al to GaN has a ratio of at least 40% and transmits light having a wavelength of less than 300nm. The method of claim 1,
And at least one semiconductor layer of the first semiconductor layer and the second semiconductor layer is disposed with an electrode to which a voltage is applied. The method of claim 1,
The electrode is a transparent electrode, the transparent electrode is a light emitting device using an electrode using gallium oxide (GaxOy). The method of claim 3,
The gallium oxide is a light emitting device in which oxygen (O) and gallium (Ga) has a ratio of any one of 1: 1, 1: 2 :, 1: 3 :, 2: 1: 2, 2: 2, 2: 3. The method according to claim 3 or 4,
A light emitting device in which a reflector is disposed on the transparent electrode. A first semiconductor layer comprising ALxGaNy;
An active layer disposed on the first semiconductor layer and emitting light;
A second semiconductor layer disposed on the active layer and comprising ALxGaNy; And
A transparent electrode disposed on the second semiconductor layer and including gallium oxide (GaxOy);
The second semiconductor layer is divided into a plurality of layers having different ratios of Al to GaN, and the transparent electrode is disposed on one layer having a ratio of Al to GaN of at least 40% among the plurality of layers. device. The method according to claim 6,
The gallium oxide is a light emitting device in which oxygen (O) and gallium (Ga) has a ratio of any one of 1: 1, 1: 2 :, 1: 3 :, 2: 1: 2, 2: 2, 2: 3.

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