JP2004048067A - Light emitting component and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a light emitting component suitable for a surface light source that is formed as a single component and has large light emitting intensity. <P>SOLUTION: An n-type GaN layer 16, a light emitting layer 18, and a p-type GaN contact layer 20 are formed in this order in correspondence with respective GaN-based light emitting diodes 14a to 14d on an insulating substrate 12. A translucent electrode 22 that is a p-type side electrode is formed flat on the p-type GaN contact layer 20 to extend to the vicinity of the edge of the n-type GaN layer 16 and in a lateral direction to form an n-type side electrode 24. Each of the components on the insulative substrate 12 is covered with a protection film 26, and the protection film 26 is opened such that tops of the translucent electrode 22 and the n-type side electrode 24 between the adjacent GaN-based light emitting diodes are partially exposed. Furthermore, internal wiring 28 is formed on the translucent electrode 22 and the n-type side electrode 24 in the opening, thereby a light emitting component 10 is obtained in which series connection is made among adjacent GaN-based light emitting diodes 14a to 14d, respectively. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a light emitting component and a method of manufacturing the same, and more particularly, to a light emitting component using a group III nitride semiconductor light emitting device and a method of manufacturing the same.

As shown in FIG. 9, as a conventional GaN-based light emitting device 1, a single transmissive electrode 3 and a pair of bonding electrodes including an anode electrode 4 and a cathode electrode 5 are formed on one insulating substrate 2. Light emitting diodes having pad electrodes formed, that is, having one light emitting portion for one chip, have been widely used.

(4) Since the conventional GaN-based light-emitting element 1 has only one light-emitting portion, it alone was not suitable as a surface light source.

Further, since only one element is formed on one insulating substrate 2 in the GaN-based light-emitting element 1, if a large-area surface light source is to be obtained, a plurality of GaN-based light-emitting elements 1 are arranged on a base and mutually Because of the necessity of connection, there is a limit on the interval between the GaN-based light emitting elements 1 adjacent to each other, and there is a problem that a surface light source having a large light emission intensity cannot be obtained.

Therefore, a main object of the present invention is to provide a light emitting component which is formed as a single component and which is suitable as a surface light source having a large light emission intensity.

In order to achieve the above object, a light emitting component of the present invention includes a substrate and a plurality of Group III nitride semiconductor light emitting devices formed and connected to the substrate, respectively.

発 光 In the light emitting component of the present invention, a plurality of group III nitride semiconductor light emitting devices are connected in series.

In the light-emitting component of the present invention, each of the group III nitride semiconductor light-emitting elements is formed on a first conductive type semiconductor layer formed on a substrate, near one end of the first conductive type semiconductor layer, and extending in the width direction. A first conductivity type side electrode, a second conductivity type semiconductor layer formed on the first conductivity type semiconductor layer, and a second conductivity type side formed on the second conductivity type semiconductor layer in a planar manner. Each of the group III nitride semiconductor light emitting devices includes an electrode, and the first conductivity type side electrode of one light emitting device of the group III nitride semiconductor light emitting device adjacent to each other and the third group nitride semiconductor light emitting device of the other light emitting device. The two-conductivity-type-side electrode is connected by an internal wiring having a width.

発 光 The light emitting component of the present invention is set such that R1 ≒ R2, where R1 is the resistance of the semiconductor layer of the first conductivity type and R2 is the resistance of the electrode of the second conductivity type.

発 光 In the light emitting component of the present invention, the second conductivity type side electrode includes a light transmitting electrode.

発 光 In the light emitting component of the present invention, the number of group III nitride semiconductor light emitting devices is determined according to the driving voltage.

は In the light emitting component of the present invention, the group III nitride semiconductor light emitting device includes a GaN-based light emitting device.

According to the present invention, a plurality of light-emitting portions can be formed on one substrate, and a light-emitting component that is formed as a single component, has high emission intensity, and is suitable as a surface light source can be obtained.

In the light emitting component of the present invention, a plurality of group III nitride semiconductor light emitting devices are formed and connected on one substrate using a general IC manufacturing process, so that the group III nitride semiconductor light emitting devices adjacent to each other are provided. Can be made narrower than before. Therefore, a surface light source which is formed as a single component and has a high luminous intensity can be obtained.

で は In the light emitting component of the present invention, when a plurality of group III nitride semiconductor light emitting devices are connected in series, the amount of light emitted from each group III nitride semiconductor light emitting device is equalized.

In the light emitting component according to the present invention, each of the group III nitride semiconductor light emitting elements is linearly arranged, and the first conductivity type side electrode of one of the group III nitride semiconductor light emitting elements adjacent to each other and the other light emitting element. When the second-conductivity-type-side electrode of the device is connected by an internal wiring having a width, the emission intensity distribution in each group III nitride semiconductor light-emitting device is made more uniform. Further, in the light emitting component of the present invention, when (resistance R1 of the semiconductor layer of the first conductivity type) ≒ (resistance R2 of the side electrode of the second conductivity type) is set, the light emission of each group III nitride semiconductor light emitting element is achieved. The intensity distribution is substantially uniform.

Further, in the light emitting component of the present invention, when the number of the group III nitride semiconductor light emitting elements is set to be suitable for the driving voltage of the device using the light emitting component, a light emitting component applicable to various driving voltages is obtained. can get. In the light-emitting component of the present invention, the second conductivity type side electrode is formed by a translucent electrode, and in the light-emitting component of the present invention, for example, a GaN-based light-emitting device is used as the group III nitride semiconductor light-emitting device. .

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

Referring to FIGS. 1 and 2, light emitting component 10 according to an embodiment of the present invention includes an insulating substrate 12 such as a sapphire substrate, and has four GaNs (at least Ga, N) on insulating substrate 12. Semiconductor light emitting diodes 14a to 14d.

That is, on the insulating substrate 12, an n-type GaN layer (Si-doped) 16 serving as an electrode installation layer having a layer thickness of 3.0 μm and a layer thickness of 0.1 μm corresponding to each of the GaN-based light emitting diodes 14a to 14d. The light emitting layer 18 and the p-type GaN contact layer (Mg doped) 20 having a layer thickness of 0.5 μm are formed in this order.

On each of the p-type GaN contact layers 20, a light-transmitting electrode 22, which is a p-type electrode, is formed in a planar shape. 24 are formed. As can be clearly understood from FIG. 1, the translucent electrode 22 and the n-side electrode 24 are formed in parallel.

Each member on the insulating substrate 12 is covered with a protective film 26, and the translucent electrode 22 and the n-type electrode 24 between adjacent GaN-based light emitting diodes are connected in series by an internal wiring 28 having a predetermined width W1. Connected. At this time, one end of the internal wiring 28 is formed near one end edge on the light transmitting electrode 22 and extends in the width direction. Therefore, regarding one GaN-based light emitting diode, the connection point between the internal wiring 28 and the translucent electrode 22 is near the edge opposite to the formation point of the n-type side electrode 24. 1, the width W1 of the internal wiring 28 is set to be slightly smaller than the width W2 of the translucent electrode 22 and slightly larger than the length L of the n-type side electrode 24, for example. You.

パ ッ ド Furthermore, pad electrodes 30 for connection to external components are connected to the translucent electrode 22 and the n-type side electrode 24 at both ends. The pad electrode 30 is also formed in the same manner as the internal electrode 28.

Thus, by connecting the translucent electrode 22 and the n-type side electrode 24 via the internal wiring 28, the light emitting component 10 in which the four GaN-based light emitting diodes 14a to 14d are connected in series is obtained. FIG. 3 shows an equivalent circuit of the light emitting component 10.

An example of a method for manufacturing such a light emitting component 10 will be described with reference to FIG.

First, as shown in FIG. 4A, an n-type GaN layer 16, a light-emitting layer 18, and a p-type GaN contact layer 20 are formed on an insulating substrate 12 in this order by MOCVD (metal organic chemical vapor deposition). An n-type GaN layer 16 having a thickness of 3.0 μm and N _D = 10 ¹⁸ cm ⁻³ , a light emitting layer 18 having a thickness of 0.1 μm, and a film having a thickness of 0.5 μm and N _A = 10 ¹⁷ cm ⁻³ . A p-type GaN contact layer 20 is formed.

Next, as shown in FIG. 4B, the p-type GaN contact layer 20 and the light-emitting layer 18 on the insulating substrate 12 are formed by photolithography using a Ni mask and dry etching supplying chlorine gas at a pressure of 0.5 Pa. Then, n-type GaN layer 16 is removed by etching, and mesa 21 is formed. At this time, the etching depth is 0.8 μm.

Further, as shown in FIG. 4C, the n-type GaN layer 16 on the insulating substrate 12 is etched away by photolithography using a Ni mask and dry etching supplying chlorine gas at a pressure of 0.5 Pa. The recess 32 is formed so that the insulating substrate 12 is exposed. As a result, the etching depth becomes 3.6 μm, and the layers constituting the GaN-based light emitting diodes 14a to 14d are separated.

Subsequently, as shown in FIG. 4D, a 2 nm-thick Ni film and a 4 nm-thick Au film are formed on the entire upper surface of the p-type GaN contact layer 20 by electron beam evaporation under a pressure of 2 × 10 ⁻⁶ torr. Are formed in this order, and a planar light-transmitting electrode 22 is formed by photolithography. In addition, a 30 nm-thick Ti film and a 500 nm-thick Al film are formed in this order on the n-type GaN layer 16 by electron beam evaporation under a pressure of 2 × 10 ⁻⁶ torr. An n-side electrode 24 is formed near the one edge on the GaN layer 16 and extends in the width direction. The n-type side electrode 24 corresponds to a cathode electrode of a GaN-based light emitting diode.

Thereafter, as shown in FIG. 4E, a protective film 26 made of SiO ₂ having a thickness of 300 nm is formed on the entire upper surface of the chip formed in FIG. 4D by electron beam evaporation.

(5) Thereafter, the protective film 26 is etched and removed by photolithography so that an opening is formed so that a part of the upper surface of each of the translucent electrode 22 and the n-type side electrode 24 is exposed. At this time, regarding one GaN-based light emitting diode, the opening on the translucent electrode 22 is formed near the edge opposite to the location where the n-type electrode 24 is formed and extends in the width direction. The opening of the n-side electrode 24 is also formed to extend in the width direction.

Then, as shown in FIG. 4F, a 100-nm thick Ni film and a 700-nm thick Au film are formed in this order on the entire upper surface of the protective film 26 by electron beam evaporation under a pressure of 2 × 10 ⁻⁶ torr. The film is formed, and the internal wiring 28 is formed by photolithography. Therefore, regarding one GaN-based light emitting diode, the internal wiring 28 connected to the translucent electrode 22 and the internal wiring 28 connected to the n-type side electrode 24 are arranged in opposite directions from both ends of the GaN-based light emitting diode. Will be withdrawn. Although not shown in FIG. 4F, the pad electrode 30 is formed simultaneously in the same manner. One end of the internal wiring 28 and the pad electrode 30 connected to the translucent electrode 22 corresponds to the anode electrode of the GaN-based light emitting diode.

よ う Thus, the light emitting component 10 in which the four GaN-based light emitting diodes 14a to 14d are connected in series is formed.

According to the light emission intensity 10, a plurality of GaN-based light emitting diodes 14a to 14d are formed and connected on one insulating substrate 12 using a general IC manufacturing process, so that GaN-based light emitting diodes adjacent to each other are formed. Can be made narrower than before. Therefore, the light emitting component 10 which is formed as a single component and is suitable as a surface light source having a high luminous intensity is obtained.

Further, according to the light emitting component 10, as shown in FIG. 5A, the GaN-based light emitting diodes 14a to 14d can be formed on the insulating substrate 12 in a straight line. As can be seen, a large area emission is obtained.

(4) Since the GaN-based light emitting diodes 14a to 14d can be formed on the same insulating substrate 12, the GaN-based light emitting diodes 14a to 14d can be easily separated and integrated.

発 光 The emission intensity distribution of each of the GaN-based light emitting diodes 14a to 14d is as shown in FIG. The resistance of the translucent electrode 22 is Rt, the resistance of the n-type GaN layer 16 is Rn, and Rp is the resistance of the p-type GaN contact layer 20, the contact resistance between the translucent electrode 22 and the p-type GaN contact layer 20, and The resistance corresponding to the pn junction voltage is shown, and each resistance is assumed to be constant in the plane.

Each of the GaN-based light-emitting diodes 14a to 14d is linearly arranged, and the n-type electrode 24 of one of the GaN-based light-emitting diodes adjacent to each other and the light-transmitting electrode 22 of the other light-emitting diode have a width W1. When the resistance per unit area of the translucent electrode 22 is small (Rt ≒ Rn), as shown in FIG. 6A, the entire surface of the translucent electrode 22 is connected. Current flows through the n-type GaN layer 16, and the current passing through the light emitting layer 18 becomes uniform regardless of the position in the light emitting layer 18. Therefore, as shown in FIGS. 6B and 6C, the light emission from the translucent electrode 22 is substantially uniform regardless of the light emission location, and a higher light emission intensity can be obtained.

Incidentally, when the resistance per unit area of the translucent electrode 22 is large (Rt> Rn), as shown in FIG. 6D, the current passing through the light emitting layer 18 is close to the internal wiring 28, that is, near the anode electrode. concentrate. In this case, the light emission intensity in the XX section shown in FIG. 6E becomes non-uniform, but each of the GaN-based light-emitting diodes 14a to 14d is linearly arranged and one of the GaN-based light-emitting diodes adjacent to each other. The n-type side electrode 24 of the light emitting diode and the translucent electrode 22 of the other light emitting diode are connected by the internal wiring 28 having the width W1, so that the light emission intensity in the YY cross section shown in FIG. Becomes substantially uniform. Therefore, the light emission intensity is non-uniform and small compared to the case where the resistance per unit area of the light-transmitting electrode 22 is small, but the light emission intensity is uniform and large at least as compared with the prior art shown in FIG.

Further, as shown in FIGS. 7A to 7C, GaN-based light emitting diodes 14a to 14d may be formed on an insulating substrate 12a and connected in series in a U-shape. Thus, a light emitting component suitable for a surface light source can be obtained.

That is, as can be seen from FIGS. 5 and 7, by forming a plurality of GaN-based light-emitting diodes on an insulating substrate and connecting them in series, they are formed as a single component and have a large luminous intensity. A light emitting component that can be applied is obtained.

Note that driving a GaN-based light-emitting diode requires 3 V or more, and circuit operation is often performed using a 5 V power supply. When about 4 V is required per GaN-based light emitting diode (for example, when a current of 20 mA flows), when the driving voltage is 24 V, a light emitting component in which six GaN-based light emitting diodes are connected in series may be used. As described above, by using the GaN-based light-emitting diodes having the number of series elements according to the drive voltage, light emission of a large area becomes possible and the limitation of the drive voltage is reduced, so that a wide variety of applications can be expected.

Further, as shown in FIG. 8, even if a current control element such as a resistor (FIG. 8A) or an FET (FIG. 8B) is formed on the same insulating substrate together with the GaN-based light emitting diodes 14a to 14n. In this case, the GaN-based light emitting diodes 14a to 14n and the current control element can be formed monolithically on the same insulating substrate.

As described above, since an external element is not required, a small and light-weight light emitting component 10 can be obtained. In addition, not only the GaN-based light emitting diodes 14a to 14d but also the current control element can be formed of a wide gap band material, so that heat is generated. A light-emitting component 10 that is strong against light is obtained, and integration is facilitated. Furthermore, since elements are formed only on one main surface of the insulating substrate, a general IC manufacturing process can be applied in this case as well. Further, by adding a current control element as well as adjusting the number of GaN-based light emitting diodes, the limitation of the driving voltage is further reduced. Further, by adding a resistor to the GaN-based light emitting diodes 14a to 14n, it is possible to suppress a surge current at the time of assembly or use.

で は In the embodiment of FIG. 1, the case where four GaN-based light emitting diodes 14a to 14d are connected in series has been described, but it goes without saying that the number of GaN-based light emitting diodes is not limited to this.

In the above-described embodiment, a light emitting diode is described as an example of a light emitting element, but the present invention is not limited to this, and a laser may be used.

Further, as the group III nitride semiconductor light emitting element of the light emitting component 10, any group III nitride semiconductor light emitting element made of a group III nitride semiconductor containing AlN, InN, BN, InGaN or the like can be used. Can be used.

It is a top view which shows the principal part of one Embodiment of this invention. FIG. 2 is a sectional view showing the embodiment of FIG. 1. FIG. 2 is an equivalent circuit diagram illustrating the embodiment of FIG. 1. FIG. 2 is a process chart illustrating a manufacturing process of the embodiment in FIG. 1. FIG. 2A is a plan view schematically illustrating an arrangement state of the GaN-based light emitting diodes in the embodiment of FIG. 1, and FIG. 2B is a side view schematically illustrating the light emission state. FIGS. 3A to 3C are schematic views schematically showing a current flow and a light emission intensity distribution of a GaN-based light-emitting diode, wherein FIGS. The case where the resistance of the electrode is large is shown. (A) is an equivalent circuit diagram showing another embodiment of the present invention, (b) is a plan view schematically showing an arrangement state of GaN-based light emitting diodes in the embodiment, and (c) is a plan view. It is a side view which shows the light emission state typically. It is an equivalent circuit diagram which shows other embodiment of this invention, (a) shows what added resistance to the GaN-based light emitting diode, and (b) shows what added FET to the GaN-based light emitting diode, respectively. (A) is a plan view showing a conventional technique, and (b) is an end view thereof.

Explanation of reference numerals

REFERENCE SIGNS LIST 10 light-emitting component 12, 12 a insulating substrate 14 a-14 d, 14 n GaN-based light-emitting diode 16 n-type GaN buffer layer 18 light-emitting layer 20 p-type GaN contact layer 22 light-transmitting electrode 24 n-type side electrode 26 protective film 28 internal wiring 30 Pad electrode W1 Internal wiring width

Claims (4)

A light emitting component comprising a substrate and a plurality of group III nitride semiconductor light emitting devices formed and connected to the substrate, respectively,
Each of the group III nitride semiconductor light emitting devices includes a first conductive type semiconductor layer formed on the substrate, a first conductive type side electrode formed on the first conductive type semiconductor layer, and a first conductive type electrode. A second conductivity type semiconductor layer formed on the conductive semiconductor layer, and a second conductivity type side electrode formed on the second conductivity type semiconductor layer,
The first conductive type side electrode of one light emitting element of the group III nitride semiconductor light emitting element and the second conductive type side electrode of the other light emitting element which are adjacent to each other are on the first conductive type side electrode and A light emitting component connected by an internal wiring formed on the second conductivity type side electrode. A protective film is formed on the first conductivity type side electrode and the second conductivity type side electrode,
The light emitting component according to claim 1, wherein the internal wiring is connected to the first conductivity type electrode and the second conductivity type electrode via an opening in the protective film. A method for manufacturing a light-emitting component comprising a substrate and a plurality of group III nitride semiconductor light-emitting elements formed and connected to the substrate, respectively,
A first conductive type semiconductor layer formed on the substrate, a first conductive type side electrode formed on the first conductive type semiconductor layer, and a second conductive layer formed on the first conductive semiconductor layer A step of forming each of the group III nitride semiconductor light emitting devices including a semiconductor layer of a conductivity type and a second conductivity type side electrode formed on the semiconductor layer of the second conductivity type;
Forming an internal wiring on the first conductivity type side electrode and the second conductivity type side electrode to connect the group III nitride semiconductor light emitting elements adjacent to each other. Method. The step of connecting the group III nitride semiconductor light emitting device includes:
The first conductivity type side electrode of one light emitting element of the group III nitride semiconductor light emitting element and the second electrode of the other light emitting element which cover the entire top surface of each of the group III nitride semiconductor light emitting elements and are adjacent to each other. A step of forming a protective film having an opening exposing a part of the upper surface of the conductivity type electrode,
4. The light emitting component according to claim 3, further comprising a step of forming the internal wiring on an upper surface of the protective film and on an upper surface of the first conductivity type electrode and the second conductivity type electrode in the opening. Production method.

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