JPS58102587A - Semiconductor light emitting device - Google Patents

Abstract

PURPOSE:To provide a semiconductor laser characterized by a low oscillation threshold current and high differential quantum efficiency, by providing an optical waveguide in an output region, thereby improving the feedback rate between an active layer and the output region. CONSTITUTION:A positive voltage is applied to a P side electrode 19 and a negative voltage is applied to an N side electrode 20. Carriers are injected only to an active layer 16 by P-N reverse bias of epitaxial layers 10, 11, and 12. Light emission is obtained by recombination. The carriers injected into the active layer 16 are completely confined in the active layer 16 by clad layers 15 and 17, respectively. The laser light generated by the active layer 16 is guided by the clad layers 15 and 17 whose refractive index is low, and combined to the epitaxial layers 10, 11, and 12. The light guided into the active layer 16 is again guided into the core layer 11 by the clad layers 10 and 12, and resonated between cleavage planes. By forming the core layer 11 and the clad layers 10 and 12 at first, the flat waveguide, wherein the interface between the core layer and the clad layers has small uneven parts, is formed.

Description

Detailed Description of the Invention (1) Technical field of fi#1 The present invention relates to a conductor light emitting device having four output wave paths. , 4-Effect Tei Sakusaku San Long Life - High Speed II! The modulation has the advantage of being a town lie, and the fiI of optical transmission and former information office! For example, gallium alum, hi wood (GajLj people- Nmi;t
In the cow conductor lede made from TT Aichi, what determines the limit of the V-za output is the destruction due to optical damage on the V-za 4 south, and this optical damage is caused by insufficient carrier strength due to the surface. Crystallization occurs in population inversion (due to light absorption near the laser 4) Therefore, in order to increase the output of the laser, carriers should not be injected near the laser 4 and the light absorption should be reduced to 11A.
This is the M effect, so we set up an output-only waveguide that does not contain active l- in the vicinity of the laser beam collapse, and the laser source generated in the active no is absorbed into this output waveguide Kd. One powerful #1j with high output ratio! It becomes 1.

The following is a list of the conditions necessary for achieving flat output in a V-za with 4 output waves. For those who meet 01% output, Il1 min. This requires equalization of the cell efficiency and reduction of the oscillation threshold.This reduces the operating current at one output, alleviates the black occurrence caused by current injection, and suppresses the decrease in extensibility due to heating. Depends on the reason. Therefore, in order to satisfy the requirements of the government, it is necessary to efficiently return the element generated in the active layer by equalizing one and a half effects of the active layer and the output guiding strategy.

(3) Conventional technology and problems This invention@O As a conventional technology, a gallium oxide (GaAs)-aluminum gallium oxide (AjGmAs)jK semiconductor laser in which the active layer is not exposed in the direction of the output layer is cited. I will now explain the problems with the conventional method. Fig. 1 is a schematic cross-sectional view of this semiconductor layer parallel to the radar oscillation direction. In Fig. 1, l is an n-type G-type Am substrate, 3 is an n-type AtGaAa cladding H, a is a GaAa active layer, 4 is p-type AtGaAa cladding layer, 6 is p-type Ga
A-key+yg layer, 6 is A 16. Hatake G a O12A8
One output area layer represents a pill cell, and 8 represents an n@electrode.

In the semiconductor laser having this ↓-connected 411 structure, the output region layer 6 is formed in the exit direction il [near the V to the end direction, so the active layer 8 is not exposed in the direction of laser oscillation. , it is possible to prevent fatigue Ia caused by optical damage at no f4 width ◎ Also, in operation, p@lllEm
A positive voltage is applied to 7, and a negative voltage is applied to n@electrification 8, carriers are injected into the active layer 8, and luminescence is obtained by re-tightening. 0 Light is emitted by the carriers injected into the active layer 8 and the active layer. Originally, the layer 1 #44c is confined within the multi-active layer 8 in the thickness direction. However, this laser has a conductor 12&! with an original 4JI[*- in the output force region. - is not provided, the source propagates to the tfi layer propensity 8 output region, the output vAJJR pigeon 6 expands 9, the laser is reflected by the four peaks, that is, the expansion direction, and the feedback rate to the dimension tIi layer 8 is Lower it.

There has been a discovery that this results in an increase in oscillation-w1 accent and a decrease in imitation quantum efficiency.

In order to improve the original return R4K to the active layer 8, a waveguide with the original 4R4fM@t- is formed in the output region, and ~71
．． It is necessary to efficiently guide the source generated in the active layer 8 in this way.
-m and provide an optical waveguide in the output region.
! Improves the separation between the 14th layer and the output area and increases the value of 1 oscillation [
There is a K who has a low accent (Kari Kari, Sumireko Rh) and who offers a semiconductor lede.

(5) Invention a or the present invention provides a 1I11 multilayer semiconductor layer consisting of an active layer and a cladding layer that has a wider forbidden band width than the UL and R8 layers and sandwiching the active layer from above and below. The first multilayer semiconductor layer includes a core layer at the end in the direction in which the laser oscillates, and cladding layers having a smaller refractive index than the core layer and sandwiching the core layer from above and below. a third multilayer semiconductor ttst-arranging the path dA- and blocking current;
The active layer and the core layer! Subsequently, the light generated in the incubation period active layer is coupled to the second multilayer semiconductor layer to form four waves.

(6) Practical JIA Example of the Invention Hereinafter, the basic principle of the present invention will be explained using an embodiment of the present invention.
Figure 2 is a schematic cross-sectional view of a semiconductor laser parallel to the oscillation direction, showing various manufacturing processes as an example.
m thick layer 10% p-type AtGaAm core layer 11% n
By using MAt (1 g of 2-rad layer) as a dielectric crystal, the refractive index of the core layer 11 is larger than that of the cladding layers 10 and 11 provided above and below, thereby providing optical guidance with IR stability. Note that a K jW kCn type GaAl layer 18 of a three-layer structure made of AtGaAa-based material is continuously grown. This means that a
It is a friend that makes the n-type GaA1 layer 18 and the M liquid that also serves as rit good and makes it easy to crystallize.
Figure (II). ^ The thickness of each layer is 10m and 1m for the cladding layer.
The layer 11 is 0.8mm, n-type GaAs
7IIl18 is 0. Growth of a 6-layer structure (or 5HjI411 construction) with a Jl*mr oiigx figure in which a volume of 1 H is phosphoric acid (H@PO4) yarn:, 4m Hydrogen CH@o
@): Methyl alcohol (01(,υH)-1:1:@
Use fb# & -C chemical etching for 1s
A recess 14 with a depth of Q-600 μm1 leading to the jIIi plate 9, that is, approximately 2.8 to 8.5 pm, is formed in the σtT> direction.The shape of the recess 1 at this time has a large opening and a bottom. Form a small isosceles trapezoid (Figure 48tbt)
o Next, liquid phase epitaxial growth is performed again #) l!
Part 11 No. 1 has a p-type At()aAa active layer '4isp-type MutGa which becomes the n-type AjGaAa cladding layer 151 source part.
Aa cladding layer 17, further p-type G for 100 million contacts
aAa layer 18i despise 0 here g sex 416 forbidden emperor-
is made smaller than the epitaxial layer 10°11#1llL17. - Typical thickness of each layer is 1.1 for cladding/#II
1~g, OI1m% active layer is 0.1~G, l)m, 2 Rad layer 17 is p-type G until the substrate surface is almost flat.
The aAs layer 18 is 0.11. In addition, when growing the epitaxial layer 16.16 in liquid phase, n-type GaAm
A layer 1 is also formed on the layer 11, which is slightly thinner than that formed in the recess 14. Finally, p-type GaAs layer 18111
Kpill electrode 4xs, an epitaxial layer toett formed on the substrate 9 side with an n[''IIE pole go and provided outside the original waveguide section, that is, the recessed section 14.

The light emitting device is completed by moving IB between the bones in a JTI direction with respect to the laser oscillation direction (Fig. 3-I).

The operation is to apply a positive, n-positive voltage SO<negative voltage t' to the p-side electrode 19, inject carriers only into the active layer 16 through the p-n reverse bias of the epitaxial layer 10#11.11, and repeat the operation. The carriers injected into the active layer 16 emit light due to the cladding layer 1a*1 which moves in the M thickness direction. ) are completely confined within the active layer 16.

When the gain is overcome by sufficient injection current, a radar source is generated from the active layer 16. This source has a low refractive index ^
It is guided by cladding layers 11 and 17 and is coupled to epitaxial layers lO, 11, liI formed in the exit region. At this time, since the cladding layers 1o and 1s have a lower refractive index than the core layer 11, four waves are formed in the active layer 16, but four waves are formed in the core shoulder 11 by the cladding layers 1G and is. In the present invention, the light guide 8. Since the semiconductor layer having the mechanism #4 is formed, the Rade element generated from the TFI layer does not spread in the output region, and therefore the original return ratio between the TFI layer and the output region can be improved.

It is possible to reduce the oscillation range and increase the differential doji efficiency.

In addition, the Taido method of semiconductor lasers introduced in the 1m example shows that the original path in the output region, that is, the core layer 11 and the cladding 410 e l jl, is the best. To form 77,
A waveguide that is flat and has small irregularities at the interface between the core layer and the cladding layer is created, and the waveguide when guiding the waveform III! This has the advantage of reducing losses.

FIG. s is a schematic cross-sectional view parallel to the laser oscillation force direction showing an application example of the present invention, and FIG. 8 Kti51. The same parts as the IjlI side part are indicated by the same symbol ◎This application N is the Sth
The difference from the embodiment shown in the figure is that the layer thickness of the active layer 16 at the connection part between the active layer 16 and the core layer 11 forming the output optical waveguide is made thinner as it approaches the connection part. According to the application example, the active layer 16
Since the layer thickness becomes thinner near the connection part, the light intensity distribution in this part expands and has the effect of mitigating the decrease in the original total effect from the active layer 16 to the optical waveguide due to the axis shift K. 〇(7) Effects of the Invention One advantage of the present invention is that it is possible to provide the original four technique paths in the exit area.
This improves the feedback rate between the active layer and the output region, resulting in 5A@r
A semiconductor laser having a low imiiiig flow and a high imitation block efficiency can be obtained.

[Brief explanation of the drawing]

Figure Ji11 is a schematic cross-sectional view parallel to the laser firing direction in a conventional semiconductor laser, and Figure S is a cross-sectional view parallel to the direction of oscillation force, showing the #1 erected root of Honjitsu mhodan.
Figure 48 is a schematic cross-sectional view of the semiconductor V-de of this application example parallel to the oscillation direction of the V-laser. Ige eye 11!11.17 Cladding layer 8
．． 16 Active layer 6 Output area layer 7 e 19
p @@@8efAOn#Electric 11 Core layer bud! rice field 2 ro1,,L,-,-・toδ■-ra) (b)

Claims (1)

[Scope of Claims] (1) An active layer, and a refractive index smaller than that of the active layer. and a first multilayer semiconductor layer having a large system division ring and comprising cladding layers sandwiching the active layer from above and below, #
4 in the direction in which the laser of Jill's multilayer medium conductor 1-
It has an original waveguide device III consisting of a core layer and cladding layers that have a smaller refraction than the core layer and sandwich the core layer from above and below, and block current. A semiconductor discovery device in which a multilayer semiconductor layer of ill is arranged, the active layer and the core layer are connected, and t4Ig is generated in the active layer and connected to a conductor layer. (3) The active layer and the power active layer have a large frequency range and 1
A striped multi-semiconductor layer consisting of a cladding layer sandwiching the 11th-age active at- from above and below is provided, and a core layer and an optical layer are formed in four parts of the #Il multilayer in the direction in which the radar of four bodies 4 oscillates. The core layer 1 has a small refractive index, and has nine waveguide ridges consisting of cladding layers sandwiching the core layer from above and below. connecting the active layer and the core layer; The active layer thickness is thinner as the core layer and the active layer sK approaches, and the light discovered in the 1st Itl period active layer is coupled to the t-gsoφ bull conductor layer and guided. *1 ljll semiconductor fif of the patent claim
, device O