JP2000349339A - Semiconductor light emitting element and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor light emitting element for decreasing contact resistance, and for improving light extracting efficiency. SOLUTION: A light emitting layer 15 is formed on the upper face of a semiconductor substrate 11, an ohmic contact layer 18 is formed on the upper face of the light emitting layer 15, and single metallic layers or alloy layers 35a, 35b,... are scattered on the upper face of the ohmic contact layer 18. An oxide transparent conductive film 20 is formed on the upper faces of the scattered single metallic layers or alloy layers 35a, 35b,....

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting device and a method of manufacturing the same, and more particularly, to a semiconductor light emitting device with reduced contact resistance and improved light extraction efficiency, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Generally, a semiconductor light emitting device 10 is an n-type GaAs as shown in FIG.
And a buffer layer 12 such as n-type GaAs having a thickness of 0.5 μm is formed on the upper surface of the semiconductor substrate 11.

On the upper surface of the buffer layer 12, n-type In
A reflection layer 13 is provided in which about 10 pairs of layers such as _0.5 Al _0.5 P and layers such as n-type GaAs are alternately laminated, and an n-type In _0.5 Al _0.5 layer having a thickness of 0.6 μm is provided on an upper surface thereof. A cladding layer 14 such as P is formed.

The thickness of the cladding layer 14 is 1.0
An active layer 15 for forming a light-emitting element such as p-type In _0.5 (Ga _0.7 Al _0.3 ) _0.5 P doped with μm of Zn is provided, and a 1.0 μm-thick p-type InO _. A cladding layer 16 such as ₅ Al _0.5 P is formed.

The upper surface of the cladding layer 16 has a thickness of 0.1 mm.
Semiconductor layer 1 such as n-type Ga _O.3 Al _O.7 As of 1 to _{3.0 μm}
7 and a thickness of 0.01 to 0.03 μm
An ohmic contact layer 18 such as p-type GaAs is formed.

On the upper surface of the ohmic contact layer 18, a continuously formed translucent Au having a thickness of 10 to 15 nm is formed.
A metal layer 19 of Zn, Cr, or the like is provided, and an oxide transparent conductive film 20 such as indium / tin / oxide is formed on the upper surface thereof.

On the upper surface of the transparent oxide conductive film 20, a p-type bonding electrode 21 such as AuGe and Au having a thickness of 0.2 μm is provided, and on the lower surface of the semiconductor substrate 11, the thickness is reduced. An n-type electrode 22 such as 200 nm of AuGe is provided to form the semiconductor light emitting device 10.

[0008] Such a semiconductor light-emitting element 10 has a metal layer 1
9, the contact resistance can be reduced. However, if the metal layer 19 is thick, the light extraction efficiency from the active layer 15 is reduced. Conversely, if the metal layer 19 is thin, the light extraction efficiency can be improved. There was a problem of increasing the resistance.

In addition, since the metal layer 19 is formed continuously, there is a problem that even if the reflection efficiency of the reflection layer 13 is increased, light extraction is reduced.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a semiconductor light emitting device having a low contact resistance and a high light transmission, and a method of manufacturing the same.

[0011]

According to a first aspect of the present invention, a light emitting layer is formed on an upper surface of a semiconductor substrate, an ohmic contact layer is formed on an upper surface of the light emitting layer, and a monometal layer or an ohmic contact layer is formed on the upper surface of the ohmic contact layer. An object of the present invention is to provide a semiconductor light emitting device characterized in that an alloy layer is interspersed, and an oxide transparent conductive film is formed on the upper surface of the interspersed single metal layer or alloy layer.

According to a second aspect of the present invention, a light emitting layer is formed on an upper surface of a semiconductor substrate, a reaction suppressing layer is formed on the light emitting layer, and an ohmic contact layer is formed on the upper surface of the reaction suppressing layer. Provided is a semiconductor light emitting device characterized in that a single metal layer or an alloy layer is interspersed on an upper surface of an ohmic contact layer, and an oxide transparent conductive film is formed on an upper surface of the interspersed single metal layer or alloy layer. Things.

Further, according to a third aspect of the present invention, a light emitting layer is formed on an upper surface of a semiconductor substrate via a reflective layer, a reaction suppressing layer is formed on the upper surface of the light emitting layer, and an ohmic contact layer is formed on the upper surface of the reaction suppressing layer. Wherein a single metal layer or an alloy layer is interspersed on the upper surface of the ohmic contact layer, and an oxide transparent conductive film is formed on the upper surface of the interspersed single metal layer or the alloy layer. A light-emitting element is provided.

Further, the present invention provides a semiconductor light emitting device wherein the single metal layer or the alloy layer is a single metal layer of Au, Zn, Cr or an alloy layer thereof.

Further, in the invention according to claim 5, the reaction suppressing layer is preferably made of In.
It is intended to provide a semiconductor light emitting device characterized by being GaAlP.

Further, according to the invention of claim 6, a light emitting layer is formed on the upper surface of the semiconductor substrate, a reaction suppressing layer is formed on the light emitting layer, and an ohmic contact layer is formed on the upper surface of the reaction suppressing layer. A single metal layer or an alloy layer is deposited on the upper surface of the ohmic contact layer, and the deposited single metal layer or the alloy layer is heat-treated so that the single metal layer or the alloy layer is scattered on the upper surface of the ohmic contact layer. An object of the present invention is to provide a method for manufacturing a semiconductor light emitting device.

Further, the heat treatment according to the seventh aspect of the present invention is performed
An object of the present invention is to provide a method for manufacturing a semiconductor light emitting device, which is performed at a temperature of about 450 ° C.

Further, the present invention provides a method for manufacturing a semiconductor light emitting device, wherein the heat treatment is performed in an Ar atmosphere.

[0019]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

Since the semiconductor light emitting device 30 of the present invention is basically constructed in substantially the same manner as the conventional semiconductor light emitting device 10, the same parts as those of the conventional semiconductor light emitting device 10 are denoted by the same reference numerals, and 30 will be described.

The semiconductor light emitting device 30 of the present invention is provided with a semiconductor substrate 11 such as n-type GaAs as shown in FIG.
On this upper surface, a buffer layer 12 such as n-type GaAs having a thickness of 0.5 μm is formed.

On the upper surface of the buffer layer 12, n-type In
A reflection layer 13 is provided in which about 10 pairs of layers such as _0.5 Al _0.5 P and layers such as n-type GaAs are alternately laminated, and an n-type In _0.5 Al _0.5 layer having a thickness of 0.6 μm is provided on an upper surface thereof. A cladding layer 14 such as P is formed.

The upper surface of the cladding layer 14 has a thickness of 1.0
An active layer 15 for forming a light-emitting element such as p-type In _0.5 (Ga _0.7 Al _0.3 ) _0.5 P doped with μm Zn is provided, and a 1.0 μm-thick p-type InO _. A cladding layer 16 such as ₅ Al _0.5 P is formed.

The upper surface of the cladding layer 16 has a thickness of 0.1 mm.
Semiconductor layer 1 such as p-type Ga _O.3 Al _O.7 As of 1 to _{3.0 μm}
7 on the upper surface of which a thickness of 0.
A reaction suppression layer 31 for suppressing a reaction such as In _O.5 (Ga _0.65 Al _0.35 ) _{0.5 O} P of _{01 to 0.03 μm} is formed.

An ohmic contact layer 18 such as p-type GaAs having a thickness of 0.01 to 0.03 μm as shown in FIG. 5 is provided on the upper surface of the reaction suppression layer 31. The thickness as shown is 0. O1-0.2 μm n-type In
A current blocking layer 32 of _0.5 Al _0.5 P is formed.

The current blocking layer 32 is coated with a photoresist (not shown), and a portion corresponding to a current-carrying region is formed in the ohmic contact layer 1 with hot phosphoric acid or hot sulfuric acid.
8 to remove 110 μm in diameter as shown in FIG.
An m current block 33 is formed.

After the formation of the current block 33, the photoresist is removed, washed with water and dried.

As shown in FIG. 8, a metal deposited film 34 of Au, Zn, Cr or the like having a thickness of 10 to 15 nm is formed on the entire surface of the current block portion 33 and the ohmic contact layer 18.

The semiconductor substrate 11 on which the metal deposited film 34 and the like are formed is placed in a DC magnetron sputtering device (not shown), and the degree of vacuum is about 1E-3 torr and the temperature is 150 to 20.
It is heated for about 100 minutes at 0 ° C. in an atmosphere of a mixed gas having a pressure ratio of Ar and oxygen of 100: 1, and as shown in FIG. 9, a transparent oxide such as indium / tin / oxide having a thickness of 240 nm is provided. The conductive film 20 is formed.

A metal film such as AuGe having a thickness of 0.2 μm and Au having a thickness of 1 μm is vapor-deposited on the upper surface of the oxide transparent conductive film 20, and this is patterned and the like, as shown in FIG. The p-type electrode 21 for bonding is formed.

After the lower surface of the semiconductor substrate 11 is mirror-polished, a metal such as AuGe having a thickness of 200 nm is deposited to form an n-type electrode 22 as shown in FIG.

The semiconductor substrate 11 formed in this way is 35
Heat treatment in an Ar atmosphere of 0 to 450 ° C. for about 10 minutes,
The metal vapor-deposited film 34 of Au, Zn, Cr or the like is condensed to form interspersed metal particles 35a, 35b (see FIGS. 1 and 2).

The metal particles 35a, 35b,... Formed in a condensed state by condensation are about 1 μm in area of 50 μm × 50 μm.
There were zero, and the size was about 4 μm × 4 μm, which was about 0.02% of the light emitting surface.

The semiconductor substrate 11 having the metal particles 35a, 35b... Has a diameter of about 150 μm by a scribing device provided with a diamond needle (not shown) around the electrode 21.
~ 250 μm square, broken by breaking, Figure 1,
The semiconductor light emitting device 20 is formed as shown in FIG.

The semiconductor substrate 30 having the metal particles 35a, 35b... Has a light extraction efficiency of the active layer 15 of 13 compared to the conventional semiconductor light emitting device 10 having the metal layer 19.
It could be improved to 0%.

The condensed and formed metal particles 35a, 35b... And the current block portion 33 not only reduce the contact resistance between the ohmic contact layer 18 and the oxide transparent conductive film 20, but also emit light from the semiconductor. The forward voltage of the device 30 can be reduced.

Further, the forward voltage fluctuation during energization can be reduced as compared with the conventional continuous metal film 19.

In addition, since a reaction suppressing layer is provided below the ohmic contact layer 18, diffusion of metals such as Au, Ge, and Cr into the active layer 15 and crystal defects thereof during heat treatment are prevented, and a highly reliable light emitting device. Could be formed.

In the above embodiment, the semiconductor substrate 11 on which the active layer 15, the ohmic contact layer 18, the metal deposited film 34, the oxide transparent conductive film 20, etc. are formed is heat-treated. Heat treatment is performed on the semiconductor substrate 11 on which the metal deposition film 34 and the like have just been deposited,
An oxide transparent conductive film 20 or the like may be formed thereon.

The metal deposited on the upper surface of the ohmic contact layer 18 is Au, Zn, Cr or the like.
Even in the case of using a metal of an alloy such as Au, Zn, and Cr, it is possible to obtain condensed metal particles in a substantially similar manner.

[0041]

According to the first and second aspects of the present invention, a light emitting layer is formed on the upper surface of a semiconductor substrate, an ohmic contact layer is formed on the upper surface of the light emitting layer, and a monometal layer or an alloy layer is formed on the upper surface of the ohmic contact layer. And a transparent conductive oxide film is formed on the upper surface of the single metal layer or the alloy layer where the single metal layer or the alloy layer is interspersed, so that a semiconductor light emitting device having a low resistance and an improved light extraction rate can be obtained.

According to another aspect of the present invention, a light emitting layer is formed on an upper surface of a semiconductor substrate, a reaction suppression layer is formed on the light emitting layer, and an ohmic contact layer is formed on the reaction suppression layer. A single metal layer or an alloy layer is scattered on the upper surface of the ohmic contact layer, and an oxide transparent conductive film is formed on the upper surface of the scattered single metal layer or the alloy layer. Nothing.

Further, according to a third aspect of the present invention, a light emitting layer is formed on the upper surface of the semiconductor substrate via a reflective layer, a reaction suppressing layer is formed on the light emitting layer, and an ohmic contact layer is formed on the upper surface of the reaction suppressing layer. Was formed, and a single metal layer or an alloy layer was scattered on the upper surface of the ohmic contact layer, and an oxide transparent conductive film was formed on the upper surface of the scattered single metal layer or alloy layer. Can be improved.

Further, according to the present invention, a light emitting layer is formed on the upper surface of the semiconductor substrate, a reaction suppressing layer is formed on the light emitting layer, and an ohmic contact layer is formed on the upper surface of the reaction suppressing layer. Is formed, a single metal layer or an alloy layer is deposited on the upper surface of the ohmic contact layer, and the deposited single metal layer or the alloy layer is heat-treated so that the single metal layer or the alloy layer is dotted on the upper surface of the ohmic contact layer. Thus, it is possible to manufacture a semiconductor light emitting device having a low resistance and an improved light extraction rate.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an outline of a semiconductor light emitting device of the present invention.

FIG. 2 is a micrograph of the plane of FIG. 1 partially cut away.

FIG. 3 is an explanatory view showing a first manufacturing process of the semiconductor light emitting device of the present invention.

FIG. 4 is an explanatory view showing a second manufacturing process of the semiconductor light emitting device of the present invention.

FIG. 5 is an explanatory view showing a third manufacturing step of the semiconductor light emitting device of the present invention.

FIG. 6 is an explanatory view showing a fourth manufacturing step of the semiconductor light emitting device of the present invention.

FIG. 7 is an explanatory view showing a fifth manufacturing step of the semiconductor light emitting device of the present invention.

FIG. 8 is an explanatory view showing a sixth manufacturing step of the semiconductor light emitting device of the present invention.

FIG. 9 is an explanatory view showing a seventh manufacturing step of the semiconductor light emitting device of the present invention.

FIG. 10 is an explanatory view showing an eighth manufacturing step of the semiconductor light emitting device of the present invention.

FIG. 11 is an explanatory view showing a ninth manufacturing step of the semiconductor light emitting device of the present invention.

FIG. 12 is a sectional view showing an outline of a conventional semiconductor light emitting device.

DESCRIPTION OF SYMBOLS 10, 30 Semiconductor light emitting element 11 Semiconductor substrate 12 Buffer layer 13 Reflective layer 14 n-type clad layer 15 Active layer 16 p-type clad layer 17 Semiconductor layer 18 Ohmic contact layer 19 Metal layer 20 Oxide transparent conductive Film 31 Reaction suppression layer 32 Current block layer 33 Current block section 34 Metal deposition film 35a, 35b ... Metal particles

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Claims (8)

[Claims] 1. A light emitting layer is formed on an upper surface of a semiconductor substrate, an ohmic contact layer is formed on an upper surface of the light emitting layer, and a single metal layer or an alloy layer is interspersed on the upper surface of the ohmic contact layer. An oxide transparent conductive film is formed on the upper surface of the single metal layer or the alloy layer thus formed. 2. A light emitting layer is formed on an upper surface of a semiconductor substrate, a reaction suppression layer is formed on an upper surface of the light emitting layer, an ohmic contact layer is formed on an upper surface of the reaction suppression layer, and an ohmic contact layer is formed on an upper surface of the ohmic contact layer. A semiconductor light emitting device comprising: a single metal layer or an alloy layer interspersed; and a transparent oxide conductive film formed on an upper surface of the interspersed single metal layer or alloy layer. 3. A light emitting layer is formed on an upper surface of a semiconductor substrate via a reflection layer, a reaction suppressing layer is formed on the light emitting layer, an ohmic contact layer is formed on an upper surface of the reaction suppressing layer, A semiconductor light emitting device comprising: a single metal layer or an alloy layer interspersed on an upper surface of a contact layer; and a transparent oxide conductive film formed on the upper surface of the interspersed single metal layer or the alloy layer. 4. The semiconductor light emitting device according to claim 1, wherein the single metal layer or the alloy layer is a single metal layer of Au, Zn, Cr or an alloy layer thereof. 5. The method according to claim 2, wherein the reaction suppressing layer is made of InGaAlP. 6. A light emitting layer is formed on an upper surface of a semiconductor substrate, a reaction suppressing layer is formed on an upper surface of the light emitting layer, an ohmic contact layer is formed on an upper surface of the reaction suppressing layer, and an ohmic contact layer is formed on an upper surface of the ohmic contact layer. A semiconductor light-emitting element, wherein a single metal layer or an alloy layer is deposited, and the deposited single metal layer or the alloy layer is heat-treated so that the single metal layer or the alloy layer is scattered on the upper surface of the ohmic contact layer. Manufacturing method. 7. The method according to claim 6, wherein the heat treatment is performed at a temperature of 350 to 450 ° C. 8. The method according to claim 6, wherein the heat treatment is performed in an Ar atmosphere.