JPH09223841A - Surface light emitting laser and its manufacture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a surface light emitting laser that is provided with a current constricting layer structure and an extraction electrode structure and the method of manufacturing it. SOLUTION: In a surface light emitting laser introduced with a current constricting structure formed by oxidizing selectively semiconductor layers that include aluminum on semiconductor to the midway of it, the electrode constricting structure and the extraction electrode structure that are effective for the surface light emitting laser are formed simultaneously and simply by oxidizing a laser part that is the current constricted not completely and oxidizing only the extraction electrode part (1-2) completely by arranging with the leader electrode structure formed by oxidizing completely the semiconductor layer that includes the above stated aluminum to the midway of it.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a surface emitting laser having a current confinement layer and an electrode extraction structure, and a method for manufacturing the same.

[0002]

2. Description of the Related Art Surface emitting lasers operate at low threshold currents.
It is a device capable of a high-density two-dimensional integrated light source, and is expected as a light source for optical information processing, optical communication, and optical interconnection, for example. This surface emitting laser requires a current confinement structure that efficiently confines the current in the active layer.

In recent years, a method of selectively oxidizing a semiconductor layer containing aluminum (Al) has been used as a method of narrowing a current, and its possibility is expected.

However, particularly when the surface emitting laser is arrayed, in the surface emitting laser in which the current confinement structure is formed by selective oxidation, the size of the element is limited by the oxidation rate of the semiconductor containing Al. In the case where the electrode lead-out structure is not formed, a sufficient area for the electrode on the upper surface side cannot be secured, and it is very difficult to form the electrode.

On the other hand, as a method of forming an electrode lead-out structure in a surface emitting laser array, after the etched groove is filled with polyimide or the like, SiO ₂ is formed between the semiconductor layer and the electrode in the wiring lead-out portion and the pad portion of the electrode. It has been realized by sandwiching an insulating layer such as.

FIG. 3 shows a sectional view of a part of a conventional surface emitting laser array. In FIG. 3, reference numeral 3-1 is a p-electrode, 3
2 is a p-electrode electrode lead-out portion, 3-3 is a p-electrode pad portion, 3-4 is SiO ₂ , 3-5 is p-AlAs / GaA
s DBR, 3-6 are p-AlGaAs cladding layers, 3
-7 is an AlGaAs active layer, 3-8 is n-AlGaAs
Clad layer, 3-9 is n-AlAs / GaAs DB
R, 3-10 is an n-GaAs substrate, 3-11 is AlAs
The oxide current confinement and optical waveguide layers, 3-12 are polyimide embedded portions, and 3-13 are n-electrodes.

By the way, in the method of patterning the insulating film on the electrode lead-out portion 3-2, a method of patterning SiO ₂ after etching the semiconductor layer,
After forming SiO ₂ on the entire surface, there is a method of simultaneously etching the SiO ₂ layer and the semiconductor layer.

However, the former method has a problem that it is difficult to increase the yield above a certain level due to the complexity of wiring as the number of arrays increases and the positional accuracy of patterning.

Further, the latter method has a drawback that the effect of not being able to completely remove the insulator appears in the height of the electrode resistance and it becomes difficult to form a laser array having uniform operating characteristics. .

In view of the above-mentioned conventional technique, the present invention introduces an electrode lead-out structure which is formed by completely oxidizing a semiconductor layer containing Al for performing selective oxidation to effectively inject carriers into the active layer. However, it is an object of the present invention to provide a surface emitting laser capable of forming an electrode extraction structure simply and with a high yield.

[0011]

The surface emitting laser of the present invention for solving the above-mentioned problems is a surface emitting laser in which a current confinement structure is introduced by selectively oxidizing a semiconductor layer containing Al on a semiconductor halfway. It is characterized by having an electrode lead-out structure formed by completely oxidizing a semiconductor layer containing Al by selective oxidation.

The method for manufacturing a surface emitting laser according to the present invention is the method for manufacturing a surface emitting laser in which a current confinement structure is introduced by selectively oxidizing a semiconductor layer containing aluminum (Al) on a semiconductor halfway. A semiconductor layer containing aluminum (Al) is epitaxially grown on the substrate, and then the aluminum (A) is formed.
patterning the semiconductor layer containing l) to completely etch the electrode portion and the electrode lead-out portion into a predetermined shape up to the GaAs substrate by selective oxidation, and then remove the center of the electrode portion from the lateral direction of the side surface of the etching surface, The electrode portion and the electrode lead-out portion are completely oxidized to form an insulating layer, and at the same time, a current confinement layer is formed by partial oxidation.

[0013]

Embodiments of the present invention will be described below.

The surface emitting laser according to the present invention is made of Al on a semiconductor.
In a surface emitting laser in which a current confinement structure is introduced by selectively oxidizing a semiconductor layer containing Al partially,
It has an electrode lead-out structure formed by completely oxidizing a semiconductor layer containing P by selective oxidation.

Since the semiconductor containing Al is oxidized by a certain amount of depth depending on the oxidation time, it can be partially oxidized or completely oxidized depending on the shape of the mesa to be oxidized.

In the surface emitting laser of the present invention, first, the semiconductor layer containing aluminum (Al) is epitaxially grown on the GaAs substrate. Then, the semiconductor layer containing aluminum (Al) is patterned to completely etch the electrode portion, the electrode lead-out portion and the pad portion into a predetermined shape by selective oxidation. Next, the electrode lead-out portion is completely oxidized except the center of the electrode portion in the lateral direction of the side surface of the etching surface to form an insulating layer and a current constriction layer by partial oxidation.

Therefore, according to the present invention, the laser confinement portion is not completely oxidized, but only the electrode lead-out structure portion is completely oxidized, so that an efficient electrode confinement structure and electrode lead-out structure can be obtained in the surface emitting laser. The structure can be manufactured simultaneously and easily, and the laser array can be easily formed.

That is, according to the present invention, the current confinement structure and the electrode lead-out structure can be easily introduced at the same time by selective oxidation, and as a result, the surface-emitting laser array or the like can be easily manufactured. . Therefore, for optical information processing,
It can be used as a light source for optical communication and optical interconnection.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a 0.85 μ made according to the present invention.
FIG. 3 is a cross-sectional view of an m-band surface emitting laser structure.

In FIG. 1, reference numeral 1-1 is a p-electrode, 1-
2 is a p-electrode electrode lead portion, 1-3 is a p-electrode pad portion,
1-4 is SiO ₂ , 1-5 is p-AlAs / GaAs
DBR, 1-6 is p-AlGaAs cladding layer, 1-7
Is an AlGaAs active layer, 1-8 is an n-AlGaAs cladding layer, 1-9 is an n-AlAs / GaAs DBR, 1
-10 is an n-GaAs substrate, 1-11 is an AlAs oxide current confinement and optical waveguide layer, and 1-12 is an n electrode.

The surface emitting semiconductor laser of this embodiment is manufactured as follows.

First, n- is formed on the n-GaAs substrate 1-10.
AlAs and n-AlGaAs have an optical wavelength of 1
25 pairs of epitaxial growth with a film thickness of
The side reflector 1-9 is formed.

Then, the n-AlGaAs cladding layer 1-
8. AlGaAs active layer 1-7 and p-AlGaAs cladding layer 1-6 are epitaxially grown, and then pAl
As and p-AlGaAs and 1 / of their optical wavelengths, respectively
The p-side reflecting mirror 1-5 is formed by alternately epitaxially growing 20 pairs with a film thickness of 4.

After performing the above-mentioned steps, a mask pattern having a predetermined shape is formed so that the cross-sectional size of the element forming the p-electrode 1-1 is 30 μm × 30 μm and the width of the extraction electrode portion 1-2 is 20 μm. The electrode portion, the electrode lead portion, and the pad portion are patterned by using the above, and the above-described epitaxial growth layer is etched to the n-GaAs substrate 1-10.

Then, the DBR layer was formed in a steam atmosphere at high temperature.
12 μm laterally from the etching surface of the constituent AlAs
Partial oxidation on the surface emitting laser part
Current confinement layer 1-11 is introduced and the electrode is drawn out.
An insulating layer by complete oxidation is introduced into the part. That is,
Since the width of the exposed electrode portion 1-2 is 20 μm, etching
Completed by oxidation of about 12 μm from both sides
It is completely oxidized to form an insulating layer. In addition, the p electrode 1-1
The element to be formed has a size of 30 μm × 30 μm.
Then, about 12 μm of acid from the lateral direction on both sides etched
Is not completely oxidized by oxidization, and the center is about 6 μm × 6 μm
The central light exit hole portion that is not oxidized remains. Continue to
Sputtering is applied to the part of the surface that forms the head part 1-3.
Ri SiO _TwoForm 1-4.

Finally, AuGeNi / Au was vapor-deposited on the entire lower surface to form the n-electrode 1-12, and a light emitting hole was formed in the center of the device by a resist on the upper surface to perform patterning A.
uZnNi / Au is vapor-deposited to remove the resist pattern. Finally, alloying is performed in a hydrogen atmosphere at 425 ° C. to form the p electrode 1-1.

The 4 × 4 surface-emitting laser array constructed as described above was manufactured as a prototype and its characteristics were measured. As a result of comparison with the conventional electrode extraction structure shown in FIG. 3, the yield was increased by about 50%.

FIG. 2 shows an example of a wiring diagram of the p-electrode of the 0.85 μm band-emission laser structure shown in FIG. FIG.
Reference numeral 2-1 indicates an electrode lead portion (width 20 μm), 2-
Reference numeral 2 indicates an electrode portion (30 μm × 30 μm), and reference numeral 2-3 indicates a pad portion.

[0030]

As described above in detail with reference to the embodiments, according to the surface emitting laser of the present invention, the current confinement structure and the electrode lead-out structure can be simultaneously and simply introduced by using selective oxidation. It becomes possible, as in the past,
As in the method of patterning only the electrode portion, the wiring becomes complicated as the number of arrays increases, and it is difficult to increase the yield above a certain level due to the positional accuracy of the patterning.
The problem that it becomes difficult to create a laser array having uniform operating characteristics, such as the method of simultaneously etching the SiO ₂ layer and the semiconductor layer after forming O ₂ on the entire surface, is solved. The production of a surface emitting laser array and the like is simplified and the yield is high. As a result, the cost of the light source for optical information processing, optical communication, and optical interconnection can be reduced, and its use is further enhanced.

[Brief description of drawings]

FIG. 1 is a sectional view of an embodiment of the present invention.

FIG. 2 is an electrode wiring diagram of an example of the present invention.

FIG. 3 is a cross-sectional view of a surface emitting laser array having a conventional electrode extraction structure.

[Explanation of symbols]

1-1 p electrode 1-2 p-AlAs / GaAs DBR 1-3 p-AlGaAs cladding layer 1-4 AlGaAs active layer 1-6 n-AlAs / GaAs DBR 1-7 GaAs substrate 1-8 n-electrode 2-1 Electrode lead portion 2-2 Electrode portion 2-3 Pad portion 3-1 p electrode 3-2 p electrode Electrode lead portion 3-3 p electrode pad portion 3-4 SiO ₂ 3-5 p-AlAs / GaAs DBR 3-6 AlGaAs clad layer 3-7 AlGaAs active layer 3-8 n-AlGaAs clad layer 3-9 n-AlAs / GaAs DBR 3-10 GaAs substrate

Claims (2)

[Claims] 1. A surface emitting laser in which a current confinement structure is introduced by selectively oxidizing a semiconductor layer containing aluminum (Al) on a semiconductor halfway, and the semiconductor layer containing aluminum (Al) is completely oxidized by selective oxidation. A surface-emitting laser having an electrode extraction structure formed by oxidation. 2. A method of manufacturing a surface-emitting laser in which a current confinement structure is introduced by partially selectively oxidizing a semiconductor layer containing aluminum (Al) on a semiconductor, wherein the semiconductor containing aluminum (Al) is formed on a GaAs substrate. The layer is formed into an epitaxially grown layer, and then the semiconductor layer containing aluminum (Al) is patterned to form the electrode portion and the electrode lead portion by selective oxidation with GaA.
completely etching to a predetermined shape up to the substrate, and then completely oxidizing the electrode portion and the electrode lead-out portion except the central portion of the electrode portion from the lateral direction of the side surface of the etching surface to form an insulating layer and a portion. A method for manufacturing a surface emitting laser, which comprises forming a current confinement layer by oxidation.