JP3505374B2 - Light emitting components - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light emitting device,
In particular, it relates to a light emitting component using, for example, a Group III nitride semiconductor light emitting device.

[0002]

2. Description of the Related Art As shown in FIG. 9, a conventional GaN-based light emitting device 1 comprises one insulating substrate 2, one transparent electrode 3, and an anode electrode 4 and a cathode electrode 5. A light emitting diode having a pair of pad electrodes for bonding, that is, having one light emitting portion for one chip has been widely used.

[0003]

Since the conventional GaN-based light emitting device 1 has only one light emitting portion, it is not suitable as a surface light source by itself.

In addition, since only one element is formed on one insulating substrate 2 in the GaN-based light emitting element 1, when a large area surface light source is to be obtained, a plurality of GaN-based light emitting elements 1 are formed.
Since it is necessary to arrange them on the base and connect them to each other, there is a limit in the interval between the GaN-based light emitting devices 1 adjacent to each other, and there is a problem that a surface light source having a large 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 high emission intensity.

[0006]

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

[0007] emitting component of the present invention, a group III nitride semiconductor light-emitting device of the multiple is intended to be connected in series.

[0008] emitting component of the present invention, the group III nitride semiconductor light emitting device includes a first conductive type semiconductor layer of the first conductivity type formed in the first conductivity type semiconductor layer formed on a substrate side electrode includes a second conductive type semiconductor layer, and the second-conductivity-type-side electrode formed in a planar shape on the second conductive type semiconductor layer formed on the first conductive semiconductor layer, mutual are connected by the internal wiring and the second-conductivity-type-side electrode of the first-conductivity-type-side electrode and the other light-emitting element of one of the light-emitting element of the group III nitride semiconductor light-emitting element adjacent to, the width W1 of the internal wiring, The first conductivity
It is longer than the length L of the mold side electrode .

In the light emitting device of the present invention , when the resistance of the first conductivity type semiconductor layer is R1 and the resistance of the second conductivity type side electrode is R2, R1≈R2 is set.

In the light emitting device of the present invention , the second-conductivity-type-side electrode includes a translucent electrode.

In the light emitting device of the present invention , the number of Group III nitride semiconductor light emitting devices is determined according to the driving voltage.

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

In the light emitting component of the present invention , since a plurality of Group III nitride semiconductor light emitting elements are formed and connected on one substrate by using a general IC manufacturing process, Group 3 nitrides adjacent to each other are used. The distance between the semiconductor light emitting elements can be made narrower than before. Therefore, a surface light source which is formed as a single component and has a high emission intensity can be obtained.

In the light emitting device of the present invention , when a plurality of group III nitride semiconductor light emitting elements are connected in series, the amount of light emitted from each group III nitride semiconductor light emitting element is made equal.

In the light emitting device of the present invention , the respective Group III nitride semiconductor light emitting elements are linearly arranged and are adjacent to each other and the first conductivity type side electrode of one light emitting element of the Group III nitride semiconductor light emitting elements. When the second-conductivity-type-side electrode of the other light emitting element is connected by the internal wiring having a width, the light emission intensity distribution in each group III nitride semiconductor light emitting element becomes more uniform. As set forth in claim 4, when (resistance R1 of semiconductor layer of first conductivity type) ≈ (resistance R2 of side electrode of second conductivity type) is set, light emission in each group III nitride semiconductor light emitting element The intensity distribution is made substantially uniform.

Further, in the light emitting device of the present invention, if the number of the group III nitride semiconductor light emitting devices is set to match the drive voltage of the device in which the light emitting device is used, it can be applied to various drive voltages. A light emitting component is obtained. The present invention
In the light emitting component , the second conductivity type side electrode is formed of 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.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

Referring to FIGS. 1 and 2, a light emitting component 10 according to an embodiment of the present invention includes an insulating substrate 12 such as a sapphire substrate, and the like. Semiconductors containing Ga and N) based light emitting diodes 14a to 14d are formed.

That is, each Ga is formed on the insulating substrate 12.
Corresponding to the N-based light emitting diodes 14a to 14d, an n-type GaN layer (Si-doped) 16 serving as an electrode installation layer having a layer thickness of 3.0 μm, a light emitting layer 18 having a layer thickness of 0.1 μm, and a layer thickness of 0.5 μm. p-type GaN contact layer (Mg-doped) 2
0s are formed in this order.

A transparent electrode 22 which is a p-type side electrode is formed in a planar shape on each p-type GaN contact layer 20,
An n-type side electrode 24 is formed in the vicinity of one edge of each n-type GaN layer 16 and in the width direction. As you can see from Figure 1,
The translucent electrode 22 and the n-type 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 side electrode 24 between adjacent GaN-based light emitting diodes have a predetermined width W.
1 is connected in series by the internal wiring 28 having the number 1. At this time, one end of the internal wiring 28 is formed near the one end edge on the transparent electrode 22 and extends in the width direction. Therefore, regarding one GaN-based light emitting diode, the internal wiring 2
8 and the transparent electrode 22 are connected to each other in the vicinity of the edge on the side opposite to the position where the n-type side electrode 24 is formed. As can be seen from FIG. 1, the width W1 of the internal wiring 28 is set to be, for example, slightly smaller than the width W2 of the transparent electrode 22 and slightly larger than the length L of the n-type side electrode 24. It

Further, the transparent electrode 22 and the n-type side electrode 24 at both ends are connected to pad electrodes 30 for connecting to external parts, respectively. The pad electrode 30 is also formed similarly to the internal electrode 28.

As described above, by connecting the translucent electrode 22 and the n-type side electrode 24 through the internal wiring 28,
A light emitting component 10 in which four GaN-based light emitting diodes 14a to 14d are connected in series is obtained. An equivalent circuit of the light emitting component 10 is shown in FIG.

An example of a method of 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 by MOCVD (metal organic chemical vapor deposition). Epitaxial growth was performed in this order, and n-type GaN having a film thickness of 3.0 μm and N _D = 10 ¹⁸ cm ⁻³
The layer 16, the light emitting layer 18 having a thickness of 0.1 μm, and the thickness of 0.
_A p-type GaN contact layer 20 of 5 μm and N _A = 10 ¹⁷ cm ⁻³ is formed.

Then, as shown in FIG. 4 (b), photolithography using a Ni mask and chlorine gas of 0.
By the dry etching method of supplying at a pressure of 5 Pa,
The p-type GaN contact layer 20, the light emitting layer 18, and the n-type GaN layer 16 on the insulating substrate 12 are removed by etching.
The mesa 21 is formed. The etching depth at this time is 0.8 μm.

Further, as shown in FIG. 4 (c), photolithography using a Ni mask and chlorine gas of 0.
By the dry etching method of supplying at a pressure of 5 Pa,
The n-type GaN layer 16 on the insulating substrate 12 is removed by etching, and the recess 32 is formed so that the insulating substrate 12 is exposed. As a result, the etching depth is 3.6 μm.
The layers constituting the GaN-based light emitting diodes 14a to 14d are separated from each other.

Subsequently, as shown in FIG. 4D, 2 ×
By electron beam evaporation by the pressure of 10 ^@ 6 torr,
A Ni film having a thickness of 2 nm and an Au film having a thickness of 4 nm are formed in this order on the entire upper surface of the p-type GaN contact layer 20, and the planar transparent electrode 2 is formed by photolithography.
2 is formed. Further, by electron beam evaporation by the pressure of 2 × 10 ^over 6 torr, on the n-type GaN layer 16, Al film of Ti film and the thickness 500nm of thickness 30nm is deposited in this order, n-type by photolithography An n-type side electrode 24 is formed on the GaN layer 16 in the vicinity of one edge and extending in the width direction. The n-type side electrode 24 corresponds to the cathode electrode of the GaN-based light emitting diode.

Then, as shown in FIG.
A film thickness of 300 nm is formed on the entire upper surface of the chip formed in (d).
The SiO ₂ protective film 26 is formed by electron beam evaporation.

After that, the protective film 26 is removed by etching by photolithography so that the upper surfaces of the translucent electrode 22 and the n-type side electrode 24 are partially exposed. At this time, regarding one GaN-based light-emitting diode, the opening on the translucent electrode 22 is formed in the vicinity of the edge on the side opposite to where the n-type side electrode 24 is formed and extends in the width direction. Further, the opening of the n-type side electrode 24 is also formed so as to extend in the width direction.

Then, as shown in FIG. 4 (f), 2 × 1
By electron beam evaporation by pressure 0 ^over 6 torr, Au film of Ni film and the thickness 700nm of thickness 100nm on the entire upper surface of the protective film 26 is deposited in this order, the internal wiring 28 is formed by photolithography . Therefore, regarding one GaN-based light emitting diode, the internal wiring 28 and n connected to the translucent electrode 22 are
The internal wiring 28 connected to the mold side electrode 24 is drawn out in opposite directions from both ends of the GaN-based light emitting diode. Although not shown in FIG. 4F, the pad electrode 30 is similarly formed at the same time. 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.

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 emission intensity 10, a plurality of GaN is formed on one insulating substrate 12 by using a general IC manufacturing process.
Since the system light emitting diodes 14a to 14d are formed and connected, the interval between the GaN-based light emitting diodes adjacent to each other can be made narrower than the conventional one. Therefore, it is possible to obtain the light emitting component 10 which is formed as a single component and is suitable as a surface light source having a high emission intensity.

Further, according to the light emitting component 10, FIG.
As also shown in FIG. 5, since the GaN-based light emitting diodes 14a to 14d can be linearly formed on the insulating substrate 12, as shown in FIG. 5B, large area light emission can be obtained.

Since the GaN-based light emitting diodes 14a to 14d can be formed on the same insulating substrate 12, Ga
This facilitates insulation isolation and integration between the N-based light emitting diodes 14a to 14d.

Each GaN-based light emitting diode 14a-14d
The emission intensity distribution of is as shown in FIG. Translucent electrode 2
The resistance of 2 is Rt, the resistance of the n-type GaN layer 16 is Rn,
Rp represents 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 equivalent to the pn junction voltage, and each resistance is considered to be constant in the plane. To do.

Each GaN-based light emitting diode 14a-14d
Are linearly arranged, and the n-type side electrode 24 of one light emitting diode of the GaN-based light emitting diodes and the translucent electrode 22 of the other light emitting diode which are adjacent to each other are connected by an internal wiring 28 having a width W1. Therefore, when the resistance per unit area of the translucent electrode 22 is small (Rt≈
Rn) includes the translucent electrode 22 as shown in FIG.
A current flows from the entire surface to 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 becomes substantially uniform regardless of the light emitting portion, and a larger light emission intensity can be obtained.

By the way, when the resistance per unit area of the transparent electrode 22 is large (Rt> Rn), the current passing through the light emitting layer 18 is the internal wiring 28 as shown in FIG. 6D.
That is, they are concentrated near the anode electrode. In this case,
Although the emission intensity in the XX cross section shown in (e) is non-uniform, each GaN-based light emitting diode 14a to 14d is linearly arranged and n of one of the GaN-based light emitting diodes adjacent to each other. Since the mold side electrode 24 and the translucent electrode 22 of the other light emitting diode are connected by the internal wiring 28 having the width W1, the emission intensity in the YY cross section shown in FIG. 6 (f) becomes substantially uniform. . Therefore, the light emission intensity is nonuniform and smaller than that when the resistance per unit area of the translucent electrode 22 is small, but the light emission intensity is more uniform and larger than at least the conventional technique shown in FIG.

Further, as shown in FIGS. 7A to 7C, the GaN-based light emitting diode 14 is formed on the insulating substrate 12a.
Alternatively, a to 14d may be formed and connected in series in a U shape. In this case, a light emitting component formed as a single component and having a large emission intensity and suitable as 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, a single component and a high emission intensity can be obtained. A light emitting component applicable to a surface light source can be obtained.

It should be noted that 3 V or more is required to drive the GaN-based light emitting diode, and circuit operation is often performed using a 5 V power supply. If one GaN-based light emitting diode requires about 4 V (for example, when a current of 20 mA is applied), 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. Thus, the number of GaN elements in series depends on the driving voltage.
By using the system light emitting diode, light emission in a large area becomes possible, and the limitation of the driving voltage is reduced, so that the application in various fields can be expected.

As shown in FIG. 8, current control elements such as resistors (FIG. 8A) and FETs (FIG. 8B) are 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 monolithically formed on the same insulating substrate.

Since no external element is required in this way,
A small and lightweight light emitting component 10 can be obtained, and since not only the GaN-based light emitting diodes 14a to 14d but also the current control element can be formed of the wide gap band material, the light emitting component 10 that is strong against heat generation can be obtained and integrated. It becomes easy to convert. Further, since the element is formed only on one main surface of the insulating substrate, a general IC manufacturing process can be applied in this case as well. Further, not only adjusting the number of GaN-based light emitting diodes but also adding a current control element further reduces the limitation on the driving voltage. Furthermore, Ga
By adding resistance to the N-type light emitting diodes 14a to 14n, surge current during assembly or use can be suppressed.

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

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

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

[0047]

According to the present invention, a plurality of light emitting parts can be formed on one substrate, and a light emitting part which is formed as a single part and has a large emission intensity and which is suitable as a surface light source can be obtained.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of an embodiment of the present invention.

2 is a cross-sectional view showing the embodiment of FIG.

FIG. 3 is an equivalent circuit diagram showing the embodiment of FIG.

FIG. 4 is a process drawing showing the manufacturing process of the embodiment in FIG.

5 (a) is a plan view schematically showing the arrangement of GaN-based light emitting diodes in the embodiment of FIG.
(B) is a side view schematically showing the light emitting state.

FIG. 6 is an illustrative view showing an outline of a current flow and a light emission intensity distribution of a GaN-based light emitting diode, (a) to (c).
Shows the case where the resistance of the transparent electrode is small, and (d) to (f) shows the case where the resistance of the transparent electrode is large.

FIG. 7 (a) is an equivalent circuit diagram showing another embodiment of the present invention, and FIG. 7 (b) is GaN in the embodiment.
It is a top view which shows typically the arrangement | positioning state of a system light emitting diode, and (c) is a side view which shows the light emission state typically.

FIG. 8 is an equivalent circuit diagram showing another embodiment of the present invention, where (a) is a GaN-based light emitting diode to which a resistor is added, and (b) is a GaN-based light emitting diode with an FET.
Are added respectively.

FIG. 9A is a plan view showing a conventional technique, and FIG.
Is an end view thereof.

[Explanation of symbols] 10 Light emitting parts 12, 12a Insulating substrate 14a to 14d, 14n GaN-based light emitting diode 16 n-type GaN buffer layer 18 Light-emitting layer 20 p-type GaN contact layer 22 Translucent electrode 24 n-type side electrode 26 Protective film 28 Internal wiring 30 pad electrode W1 internal wiring width

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) H01L 33/00

Claims (4)

(57) [Claims] 1. A light emitting component comprising a substrate and a plurality of group III nitride semiconductor light emitting devices formed and connected to the substrate, each group III nitride semiconductor light emitting device.
The element is a semiconductor of the first conductivity type formed on the substrate.
Layer, a first conductive layer formed on the first conductive type semiconductor layer
A mold side electrode, a first electrode formed on the first conductive semiconductor layer,
Two-conductivity-type semiconductor layer, and the second-conductivity-type semiconductor layer
One of the group III nitride semiconductor light-emitting devices including the second-conductivity-type-side electrode formed above and adjacent to each other.
In front of the first conductivity type side electrode of the light emitting element and the other light emitting element
The second conductivity type side electrode is connected by an internal wire, and the width W1 of the internal wire is the length of the first conductivity type side electrode.
A light-emitting component that is larger than L. 2. The width W1 of the internal wiring is the second conductive layer.
The light-emitting component according to claim 1, which is smaller than the width W2 of the mold-side electrode . 3. Each group III nitride semiconductor light emitting device is directly
The light emitting component according to claim 1, wherein the light emitting component is arranged in a line . 4. The group III nitride semiconductor light emitting device is Ga
The method according to claim 1, which includes an N-based light emitting device.
Light emitting parts on board.