KR20080000784A - Light emitting device having zenor diode therein and the fabrication method thereof - Google Patents

Abstract

A light emitting device containing a zener diode and a method for manufacturing the light emitting device are provided to prevent a damage to a diode due to a reverse current by preventing an ESD(ElectroStatic Discharge). An n-type semiconductor layer is formed on a p-type silicon substrate(110). An undoped semiconductor layer(140) is formed on the n-type semiconductor layer. An activation layer(150) is formed on the undoped semiconductor layer. A p-type semiconductor layer(160) is formed on the activation layer. The n-type semiconductor layer, the undoped semiconductor layer, the activation layer, and the p-type semiconductor layer are patterned such that a zener diode and a light emitting diode are formed. The zener diode is formed by pn-bonding a p-type silicon substrate with an n-type silicon substrate. The light emitting diode includes the p-type semiconductor layer, the activation layer, the undoped semiconductor layer, and the n-type semiconductor layer.

Description

LIGHT EMITTING DEVICE HAVING ZENOR DIODE THEREIN AND THE FABRICATION METHOD THEREOF

1 is a cross-sectional view illustrating a light emitting device according to an embodiment of the present invention.

2 is a cross-sectional view showing an example of a light emitting diode package equipped with a light emitting device according to an embodiment of the present invention.

3 is an equivalent circuit diagram of the LED package of FIG.

4 is a flowchart illustrating a manufacturing process of the light emitting device illustrated in FIG. 1.

5 to 7 are cross-sectional views illustrating a process of manufacturing the light emitting device illustrated in FIG. 1.

<Description of the symbols for the main parts of the drawings>

100 light emitting element 110 p-type silicon substrate

120 u-GaN layer 121 first u-GaN layer

122: second u-GaN layer 130: n-GaN layer

131: first n-GaN layer 132: second n-GaN layer

140: u-GaN layer 150: active layer

160: p-GaN layer 170: transparent electrode layer

181, 182, 183, 184: electrode pads 191, 192: lead

The present invention relates to a light emitting device and a manufacturing method thereof, and more particularly to a light emitting device having a zener diode and a manufacturing method thereof.

A light emitting diode is an electroluminescence device that emits light by a forward current. Compound semiconductors such as indium phosphorus (InP), gallium arsenide (GaAs) and gallium phosphorus (GaP) have been used as materials for light emitting diodes emitting red or green light, and gallium nitride (GaN) compound semiconductors And it has been developed and used as a material of a light emitting diode that emits blue light.

Light emitting diodes are widely used in various display devices, backlight sources, and the like. Recently, a technology for emitting white light by using three light emitting diode chips emitting red, green, and blue light, or converting wavelengths using phosphors has been developed. Therefore, the lighting device is also expanding its application range.

In general, GaN-based compound semiconductors are epitaxially grown on sapphire substrates with similar crystal structures and lattice constants to reduce the occurrence of crystal defects. Since sapphire is an insulating material, electrode pads of the light emitting diode are formed on the growth surface of the epi layer. However, when a substrate of an insulating material such as sapphire is used, it is difficult to prevent electrostatic discharge due to an electrostatic charge introduced from the outside, and thus damage of the diode is likely to be caused, thereby reducing the reliability of the device. Therefore, when packaging a light emitting diode, a separate zener diode is used together with the light emitting diode to prevent electrostatic discharge. However, Zener diodes are expensive and the addition of processes to mount Zener diodes increases the number of LED package processes and manufacturing costs.

In addition, sapphire has a low thermal conductivity, and thus does not easily release heat generated from the light emitting diodes to the outside. This low heat dissipation performance makes it difficult to apply light emitting diodes in applications requiring high power.

SUMMARY OF THE INVENTION The present invention has been made in an effort to provide a light emitting device including a light emitting diode and a zener diode in a single chip.

Another technical problem to be achieved by the present invention is to provide a light emitting device capable of achieving high output by using a substrate having excellent heat dissipation performance.

According to an aspect of the present invention for achieving the above technical problem, the step of forming an n-type semiconductor layer on a p-type silicon substrate, the step of forming an undoped semiconductor layer on the n-type semiconductor layer, and the undoped semiconductor Forming an active layer on the layer, forming a p-type semiconductor layer on the active layer, patterning the n-type semiconductor layer, an undoped semiconductor layer, an active layer, and a p-type semiconductor layer. A method of manufacturing a light emitting device, the method comprising: forming a zener diode having a pn junction and a light emitting diode comprising the p-type semiconductor layer, an active layer, an undoped semiconductor layer, and an n-type semiconductor layer.

The forming of the zener diode and the light emitting diode may include forming a zener diode on the p-type silicon substrate by patterning the p-type semiconductor layer, the active layer, the undoped semiconductor layer, and the n-type semiconductor layer. And forming a light emitting diode spaced apart from the second semiconductor layer region, and etching a portion of the p-type semiconductor layer, the active layer, and the undoped semiconductor layer in the second semiconductor layer region. The method may further include exposing a portion of the semiconductor layer to expose the n-type semiconductor layer by removing a p-type semiconductor layer, an active layer, and an undoped semiconductor layer from the first semiconductor layer region.

The light emitting device manufacturing method may include an n-type semiconductor layer in the first semiconductor layer region, an n-type semiconductor layer and a p-type semiconductor layer in the second semiconductor layer region, and a lower surface of the p-type silicon substrate, respectively. The method may further include forming an electrode pad.

The light emitting device manufacturing method includes a first lead electrically connected to respective electrode pads formed on a lower surface of the p-type silicon substrate and an n-type semiconductor layer on the second semiconductor layer region, and the first semiconductor layer region. The method may further include forming a second lead electrically connected to each of the electrode pads formed in the n-type semiconductor layer and the p-type semiconductor layer in the second semiconductor layer region.

In the light emitting device manufacturing method, the n-type semiconductor layer is formed on the p-type silicon substrate through the undoped semiconductor layer in the step of forming the n-type semiconductor layer, and the zener diode and the light emitting diode are formed in the step of forming the n-type semiconductor layer. The zener diode may be formed by patterning the undoped semiconductor layer formed between the p-type silicon substrate and the n-type semiconductor layer to form a pn junction between the p-type silicon substrate, the undoped semiconductor layer, and the n-type semiconductor layer.

According to another aspect of the present invention, a p-type silicon substrate having a first semiconductor layer region and a second semiconductor layer region, and a zener diode formed in a first semiconductor layer region on the p-type silicon substrate together with the p-type silicon substrate A first n-type semiconductor layer exhibiting characteristics, a second n-type semiconductor layer formed in a second semiconductor layer region on the substrate, and spaced apart from the first n-type semiconductor layer, and formed on the second n-type semiconductor layer A light emitting device comprising an undoped semiconductor layer, an active layer formed on the undoped semiconductor layer, and a p-type semiconductor layer formed on the active layer and exhibiting zener diode characteristics together with the second n-type semiconductor layer, the undoped layer, and the active layer. To provide.

The first and second n-type semiconductor layers may be formed from the same n-type semiconductor layer grown on the p-type silicon substrate.

The light emitting device is a first undoped semiconductor layer formed between the p-type silicon substrate and the first n-type semiconductor layer, and is formed between the p-type silicon substrate and the second n-type semiconductor layer, the first undo The semiconductor device may further include a second undoped semiconductor layer spaced apart from the loft semiconductor layer.

In the light emitting device, the p-type semiconductor layer, the active layer, and the undoped semiconductor layer may be formed on one region of the second n-type semiconductor layer, and the other region of the second n-type semiconductor layer may be exposed.

The light emitting device includes an upper portion of the first n-type semiconductor layer and the second n-type semiconductor layer of the second semiconductor layer region, an upper portion of the p-type semiconductor layer of the second semiconductor layer region, It may be configured to further include an electrode pad formed on the lower surface of the p-type silicon substrate, respectively.

A first lead electrically connected to respective electrode pads formed on an upper surface of the second n-type semiconductor layer of the second semiconductor layer region and a lower surface of the p-type silicon substrate; and a first n of the first semiconductor layer region. The semiconductor device may further include a second lead electrically connected to each of the electrode pads formed in the p-type semiconductor layer and the p-type semiconductor layer in the second semiconductor layer region.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. The following embodiments are provided as examples to ensure that the spirit of the present invention to those skilled in the art will fully convey. Accordingly, the invention is not limited to the embodiments described below and may be embodied in other forms. And, in the drawings, the width, length, thickness, etc. of the components may be exaggerated for convenience. Like numbers refer to like elements throughout.

1 is a cross-sectional view for describing a light emitting device 100 according to an embodiment of the present invention.

Referring to FIG. 1, the p-type silicon substrate 110 has a zener diode region A and a light emitting diode region B. FIG.

The p-type silicon substrate 110 is generally used in a semiconductor manufacturing process, and may be provided in a larger size than the sapphire substrate, and is inexpensive. In addition, the p-type impurities may be further doped into the p-type silicon substrate 110 by using an ion implantation technique such as implantation.

The first u-GaN layer 121 is positioned on the zener diode region A. FIG.

The first n-GaN layer 131 is positioned on the first u-GaN layer 121.

The p-type silicon substrate 110, the first u-GaN layer 121, and the first n-GaN layer 131 are p-n bonded to form a zener diode 101.

Meanwhile, the second second u-GaN layer 122 is positioned on the light emitting diode region B of the p-type silicon substrate 110.

The second n-GaN layer 132 is positioned on the second u-GaN layer 122.

The second u-GaN layer 122 and the second n-GaN layer 132 are spaced apart from the first u-GaN layer 121 and the first n-GaN layer 131, respectively.

The first and second u-GaN layers 121 and 122 may be formed from the same u-GaN layer grown on the p-type silicon substrate 110. That is, the first and second u-GaN layers 121 and 122 may be formed by separating the u-GaN layers grown on the p-type silicon substrate 110.

The first and second n-GaN layers 131 and 132 may be formed from the same n-GaN layer formed on the first and second u-GaN layers 121 and 122. That is, the first and second n-GaN layers 131 and 132 may be formed by separating the n-GaN layers grown on the first and second u-GaN layers 121 and 122.

Meanwhile, the p-GaN layer 160 is positioned on one region of the second n-GaN layer 132. The other region of the second n-GaN layer 132 is exposed.

Another u-GaN layer 140 and an active layer 150 are interposed between the second n-GaN layer 132 and the p-GaN layer 160.

In this case, the u-GaN layer 140 interposed between the second n-GaN layer 132 and the active layer 150 injects electrons supplied from the second n-GaN layer 132 into the active layer 150. In addition, the active layer 150 grown on the u-GaN layer 140 is grown to a semiconductor layer having good crystallinity.

In other words, the active layer 150 is grown on the u-GaN layer 140 rather than on the second n-GaN layer 132 without interposing the u-GaN layer 140, thereby improving crystallinity. The light emitting efficiency is improved more than when the u-GaN layer 140 is absent, and the IR and Vf characteristics of the light emitting device are improved as a whole.

The active layer 150 may be a single quantum well formed of a single layer or a multi-quantum well of a stacked structure.

The p-GaN layer 160, the active layer 150, the u-GaN layer 140, and the second n-GaN layer 132 constitute the light emitting diode 102.

The transparent electrode layer 170 is positioned on the p-GaN layer 160. The transparent electrode layer 170 may be formed of an indium tin oxide film (ITO) or a transparent metal film such as Ni / Au.

N-type electrode pads 181 and 183 are formed on the first and second n-GaN layers 131 and 132, and p is formed on an upper surface of the transparent electrode layer 170 and a lower surface of the p-type silicon substrate 110. Type electrode pads 182 and 184 are formed. The electrode pads 181, 182, 183, and 184 are used as contact pads that electrically connect the zener diode 101 and the light emitting diode 102 to an external circuit.

In an embodiment, the first and second u-GaN layers 121 and 122, the first and second n-GaN layers 131 and 132, the u-GaN layer 140, the active layer 150, and p− GaN layer 160 is used, but, the semiconductor layers (121, 122, 131, 132, 140, 150, 160) is _{Al x In y Ga 1 -x- y} N (0≤x, y, x + y≤ It may be formed of a binary to four-membered compound semiconductor layer represented by 1).

According to the present embodiment, by forming the light emitting diode 102 on the p-type silicon substrate 110, it is possible to easily discharge the heat generated by the light emitting diode 102. In addition, since the light emitting device according to the present embodiment includes the zener diode 101 therein, damage due to electrostatic discharge can be prevented. Therefore, in the related art, a zener diode mounted with a light emitting element can be omitted, thereby reducing the number of package processes and the cost of package manufacture.

In addition, by including the u-GaN 140 between the second n-GaN layer 132 and the active layer 150 constituting the light emitting diode 102 to improve the crystallinity of the active layer 150 to improve the Vf of the light emitting diode. Can be improved.

2 is a cross-sectional view illustrating an example of a light emitting diode package equipped with a light emitting device 100 according to an exemplary embodiment of the present invention, and FIG. 3 is an equivalent circuit diagram of the light emitting diode package of FIG. 2.

Referring to FIG. 2, the LED package includes leads 191 and 192 for electrically connecting the LED 100 to an external power source. The light emitting device 100 is die bonded on the first lead 191, whereby the p-type silicon substrate 110 is electrically connected to the first lead 191.

Meanwhile, the n-type electrode pad 183 on the light emitting diode 102 is electrically connected to the lead 191 through a bonding wire, and the n-type electrode pad 181 on the zener diode 101 and the light emitting diode 102 on the light emitting diode 102 are electrically connected. The p-type electrode pad 182 is electrically connected to the lead 192 through bonding wires. Accordingly, the light emitting diode 102 and the zener diode 101 are connected in anti-parallel as in the circuit shown in FIG.

When negative power is connected to the first lead 191 and positive power is connected to the second lead 192, forward power is applied to the light emitting diode 102 so that light is emitted. Meanwhile, the zener diode 101 prevents the forward voltage of the light emitting diode 102 from being excessively increased, thereby preventing the light emitting diode 102 from being damaged by the overvoltage. The breakdown voltage of the zener diode 101 may be controlled by adjusting the doping concentration of the p-type silicon substrate 110 and / or the doping concentration of the first n-GaN layer 131.

4 is a flowchart illustrating a manufacturing process of the light emitting device illustrated in FIG. 1, and FIGS. 5 to 7 are cross-sectional views illustrating a method of manufacturing a light emitting device according to an exemplary embodiment.

4 and 5, a p-type silicon substrate 110 is prepared in a process chamber (not shown) (S1). The p-type silicon substrate 110 has a lattice constant similar to that of the semiconductor layer to be formed thereon.

Thereafter, a u-GaN (undoped-GaN) layer 120 is formed on the p-type silicon substrate 110 (S2).

The u-GaN layer 120 is interposed between the p-type silicon substrate 110 and the n-GaN layer 130 and is made of undoped GaN.

The u-GaN 120 is intended to effectively form the n-GaN layer 130 made of GaN-based material thereon with high quality.

An n-GaN layer 130 is formed on the u-GaN layer 120 (S3).

The n-GaN layer 130 may be formed by doping silicon (Si) in GaN.

The u-GaN layer 120 and the n-GaN layer 130 may be formed of metal organic chemical vapor deposition (MOCVD), hydride vapor phase epitaxy (HVPE), or molecular beam growth (molecular). beam epitaxy (MBE) or the like.

The u-GaN layer 140 is again formed on the n-GaN layer 130 (S4). The u-GaN layer 140 is intended to effectively form the active layer 150 made of GaN-based material thereon with high quality.

The active layer 150 is formed on the u-GaN layer 140 (S5).

The active layer 150 is an area where electrons and holes are recombined, and includes InGaN / GaN. The emission wavelength emitted from the light emitting diode is determined by the type of material constituting the active layer 150. The active layer 150 may be a multilayer film in which a quantum well layer and a barrier layer are repeatedly formed. A quantum well layer and the barrier layer may be a semiconductor layer 2-to 4 won the compounds represented by the general formula _{Al x In y Ga 1 -x- y} N (0≤x, y, x + y≤1).

A p-GaN layer 160 is formed on the active layer 150 (S6).

The p-GaN layer 160 may be formed by doping zinc (Zn) or magnesium (Mg) in GaN, and may include a p-type cladding layer.

4 and 6, the p-GaN layer 160, the active layer 150, the u-GaN layer 140, the n-GaN layer 130, and the u-GaN layer 120 are photographed and etched. Patterning by using to separate the layers (120, 130, 140, 150, 160) (S7).

Accordingly, the first u-GaN layer 121, the first n-GaN layer 131, the u-GaN layer 140, the active layer 150, and the p-GaN layer 160 on the zener diode region A are thus formed. And the second u-GaN layer 122, the second n-GaN layer 132, the u-GaN layer 140, the active layer 150, and the p-GaN layer 160 on the light emitting diode region B. Spaced apart from each other.

4 and 7, the p-GaN layer 160, the active layer 150, and the u-GaN layer 140 are again patterned to form the p-GaN layer 160 and the active layer on the light emitting diode region B. 150, part of the u-GaN layer 140 is removed (S8). As a result, the p-GaN layer 160, the active layer 150, and the u-GaN layer 140 remain on one region of the second n-GaN layer 132 on the light emitting diode region B, and the other region remains. The second n-GaN layer 132 is exposed.

Meanwhile, the p-GaN layer 160, the active layer 150, and the u-GaN layer 140 on the zener diode region A are removed (S9). The p-GaN layer 160, the active layer 150, and the u-GaN layer 140 on the zener diode region A include the p-GaN layer 160, the active layer 150, and u− on the light emitting diode region B. It may be removed together while removing a portion of the GaN layer 140.

The transparent electrode layer 170 is formed on the p-GaN layer 160 (S10). The transparent electrode layer 170 may be formed of a transparent metal such as indium tin oxide (ITO) or Ni / Au by using an electron beam evaporation method or a plating technique. Thereafter, n-type electrode pads 181 and 183 of FIG. 1 are formed on the exposed first and second n-GaN layers 131 and 132, and p-type electrode pads are formed on the transparent electrode layer 170. 182 is formed (S10). In addition, the electrode pad 184 may be formed on the bottom surface of the p-type silicon substrate 110. Thus, the light emitting device 100 of FIG. 1 is completed.

In the present embodiment, the first u-GaN layer 121, the first n-GaN layer 131, the u-GaN layer 140, the active layer 150, and the p-GaN layer on the zener diode region A 160, the second u-GaN layer 122, the second n-GaN layer 132, the u-GaN layer 140, the active layer 150, and the p-GaN layer on the light emitting diode region B ( P-GaN layer 160 on the light emitting diode region (B), the active layer 150, a portion of the u-GaN layer 140 and the p-GaN layer 160 on the zener diode region (A). Although the active layer 150 and the u-GaN layer 140 are described as being removed, the p-GaN layer 160, the active layer 150, and the u-GaN layer 140 are first patterned, and then a zener diode region ( The first u-GaN layer 121 and the first n-GaN layer 131 on A), the second u-GaN layer 122 and the second n-GaN layer 132 on the light emitting diode region B. It may be separated into a u-GaN layer 140, an active layer 150, a p-GaN layer 160.

In addition, the transparent electrode layer 170 is described as being formed after the p-GaN layer 160 is patterned, but after growing the p-GaN layer 160 (160 in FIG. 5), the p-GaN layer 160 It may be formed on the phase.

According to the present embodiment, a light emitting device having a zener diode 101 and a light emitting diode 102 in a single chip can be manufactured.

The present invention is not limited to the above described embodiments, and various modifications and changes can be made by those skilled in the art, which are included in the spirit and scope of the present invention as defined in the appended claims.

According to an exemplary embodiment of the present invention, since a light emitting diode and a zener diode may be provided in a single chip through a series of processes for manufacturing a light emitting diode, a zener diode mounted with a conventional light emitting device may be omitted. In addition to reducing the number of packaging processes and manufacturing costs for manufacturing, it is possible to prevent electrostatic discharges caused by static electricity from the outside, thereby preventing damage to the diode due to reverse current. Can be improved.

In addition, it is possible to provide a light emitting device capable of achieving a high output by adopting a silicon substrate excellent in heat dissipation performance.

In addition, when the active layer constituting the light emitting diode is grown, it is grown between the active layer and the n-type semiconductor layer through an undoped semiconductor layer such as a u-Gan layer, thereby improving the crystallinity of the active layer, and thus the luminous efficiency of the active layer. By improving the IR and Vf characteristics of the light emitting device can be improved.

Claims (11)

forming an n-type semiconductor layer on the p-type silicon substrate, Forming an undoped semiconductor layer on the n-type semiconductor layer; Forming an active layer on the undoped semiconductor layer; Forming a p-type semiconductor layer on the active layer; A Zener diode formed by patterning the n-type semiconductor layer, the undoped semiconductor layer, the active layer, and the p-type semiconductor layer, and the p-type silicon substrate and the n-type semiconductor layer, and the p-type semiconductor layer, the active layer, and the undoped A light emitting device manufacturing method comprising forming a light emitting diode comprising a semiconductor layer and an n-type semiconductor layer. The method of claim 1, wherein the forming of the zener diode and the light emitting diode, A first semiconductor layer region for forming a zener diode on the p-type silicon substrate by patterning the p-type semiconductor layer, an active layer, an undoped semiconductor layer, and an n-type semiconductor layer, and a second semiconductor layer for forming a light emitting diode Forming a spaced area; Etching a portion of the p-type semiconductor layer, the active layer, and the undoped semiconductor layer in the second semiconductor layer region to expose a portion of the n-type semiconductor layer; And removing the p-type semiconductor layer, the active layer, and the undoped semiconductor layer in the first semiconductor layer region to expose the n-type semiconductor layer. The method according to claim 2, Forming electrode pads on an n-type semiconductor layer in the first semiconductor layer region, on an n-type semiconductor layer and a p-type semiconductor layer in the second semiconductor layer region, and on a lower surface of the p-type silicon substrate, respectively Light emitting device manufacturing method further comprising. The method according to claim 3, First leads electrically connected to respective electrode pads formed on the bottom surface of the p-type silicon substrate and on the n-type semiconductor layer of the second semiconductor layer region, the n-type semiconductor layer of the first semiconductor layer region and the And forming second leads electrically connected to respective electrode pads formed in the p-type semiconductor layer in the second semiconductor layer region. The method according to claim 1, In the forming of the n-type semiconductor layer, the n-type semiconductor layer is formed on the p-type silicon substrate via an undoped semiconductor layer. The forming of the zener diode and the light emitting diode may be performed by patterning the undoped semiconductor layer formed between the p-type silicon substrate and the n-type semiconductor layer to form the p-type silicon substrate, the undoped semiconductor layer, and the n-type semiconductor layer. A light emitting device manufacturing method for forming a Zener diode formed by pn junction. A p-type silicon substrate having a first semiconductor layer region and a second semiconductor layer region, A first n-type semiconductor layer formed in a first semiconductor layer region on the p-type silicon substrate and exhibiting zener diode characteristics together with the p-type silicon substrate; A second n-type semiconductor layer formed in the second semiconductor layer region on the substrate and spaced apart from the first n-type semiconductor layer; An undoped semiconductor layer formed on the second n-type semiconductor layer, An active layer formed on the undoped semiconductor layer, And a p-type semiconductor layer formed on the active layer and exhibiting zener diode characteristics together with the second n-type semiconductor layer, the undoped layer, and the active layer. The light emitting device of claim 6, wherein the first and second n-type semiconductor layers are formed from the same n-type semiconductor layer grown on the p-type silicon substrate. The method according to claim 6, A first undoped semiconductor layer formed between the p-type silicon substrate and the first n-type semiconductor layer; And a second undoped semiconductor layer formed between the p-type silicon substrate and the second n-type semiconductor layer and spaced apart from the first undoped semiconductor layer. The light emitting device of claim 6, wherein the p-type semiconductor layer, the active layer, and the undoped semiconductor layer are positioned on one region of the second n-type semiconductor layer, and the other region of the second n-type semiconductor layer is exposed. The method according to claim 6, An upper portion of the first n-type semiconductor layer in the first semiconductor layer region and a second n-type semiconductor layer in the second semiconductor layer region, an upper portion of the p-type semiconductor layer in the second semiconductor layer region, and the p-type silicon The light emitting device further comprises an electrode pad formed on the lower surface of the substrate. The method according to claim 10, A first lead electrically connected to respective electrode pads formed on an upper surface of the second n-type semiconductor layer of the second semiconductor layer region and a lower surface of the p-type silicon substrate; and a first n of the first semiconductor layer region. And a second lead electrically connected to each of the electrode pads formed on the p-type semiconductor layer in the region of the second semiconductor layer.

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