JPS6010688A - Semiconductor light emitting device and manufacture thereof - Google Patents

Abstract

PURPOSE:To enable to improve the periodicity of a photowaveguide by periodically varying the carrier density by implanting ions to the surface of the photowaveguide. CONSTITUTION:H<+> or Si<2+> ions are implanted to the surface of a P type InP layer 3 at a pitch P. When the light which propagates in a P type GaInAsP core layer 2 passes a distributed reflector 9 of a region that periodically varies in the carrier density, the refractive index periodically varies due to the variation in the carrier density, and feedback action is affected, thereby propagating in reverse direction.

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field of the Invention The present invention relates to a semiconductor light emitting device having a distributed reflector and a method for manufacturing the same.

Prior Art and Problems Conventional distributed reflection type semiconductor light emitting devices (lasers) are constructed by forming periodic irregularities on the surface of a cladding layer using a ring run mask and wet chemical etching technology.

However, in this case, the period of the unevenness to be formed is 0.1 to 0.
Since the mask is extremely short at 4 μm, it is difficult to manufacture a mask, and since side etching is also performed on the underside of the mask during chemical etching, it is difficult to obtain irregularities with good periodicity.

OBJECTS OF THE INVENTION The present invention is intended to solve the above-mentioned problems, and it is an object of the present invention to provide a semiconductor light emitting device equipped with a distributed reflector with good periodicity and a method for manufacturing the same.

Structure of the Invention In the present invention, the above object is achieved by constructing a distributed reflector with a flat surface by utilizing the fact that the refractive index of a semiconductor material changes depending on the carrier concentration.

Examples of the invention The invention will now be described in detail in conjunction with the drawings.

FIG. 1 is a front sectional view of a semiconductor light emitting device 20 according to the present invention. When manufacturing this semiconductor light emitting device 20, a p-type (100) IrLP substrate (first cladding layer) 1
On top of this, a p-type Ga1nAsP core layer (a core layer with a higher refractive index than the first cladding layer, λJ#, 1.35 μm) 2 is formed to a thickness of about 0.7 μm, and on top of this, a p-type 1nP layer ( A second cladding layer with a lower refractive index than the core layer, p=2
x 1018 cm-3) 3 to a thickness of approximately 0.4 μm to constitute an optical waveguide. Then apply a layer on top of it to a thickness of about 0.
17 μm undoped Ga1nAsP layer (active layer, λy
= 1.55 ttm ) 4 and n-type 1nP layer 5 are sequentially formed, both ends of the undoped Ga1nP layer 5 are removed by etching, and p-type 1nP layer 5 is formed in the removed portion as shown in the figure.
The P layer 6 is exposed. Next, this exposed p-type 1nP layer 6
H+ or Si2 on the surface as shown in detail in Figure 2.
+ is implanted at a pitch (period) P using ion implantation technology (details will be described later). 6 shows this ion implantation part,
The implantation depth D is 0.2 to Q, 31m above, the width W is about 0.15μm, and the period P is 480OA (same as the wavelength in the pipe)
shall be. The carrier concentration of this ion implantation part 6 is about 5
X1016cm-'. Finally, p-type 1nP substrate 1
The semiconductor light emitting device 20 is constructed by forming poles 7 and 8 on the n-type 1nP layer 5, respectively.

Positive electrode 1 is connected to pole 7 on the p side of this semiconductor light emitting device 20.

When a negative voltage is applied to the n-side electrode 8, the active layer (Gal
A current is injected into the nAaP layer) 4 and it emits light. This generated light propagates through the active layer 4 and transmits the p-type Ga1 located below.
It couples to the nAsP core layer 2 and propagates mainly through the p-type Ga1 nAsP core layer 2 near the terminal end of the active layer 4 . p-type Ga
When the light propagating through the 1nAsP core layer 2 passes through the distributed reflector 9 (forming part of the implanted part 6 of the optical waveguide), which is a region where the carrier concentration changes periodically, the refractive index changes periodically due to the carrier concentration change. Since it changes to , it receives a feedback effect and propagates in the opposite direction. As this process is repeated, when the gain overcomes the loss, laser oscillation occurs in the directions of arrows A and A'.

Next, a method of manufacturing the distributed reflector 9 by ion implantation will be explained.

The conditions for implanting ions into the p-type 1nP layer 6 whose surface has been peeled off are as follows: In the case of St 2 , the degree of vacuum is 10 torr!
.

Accelerating voltage 60-50KOr, driving depth approximately 0.2μm
, the dose is 1014 pieces/cm2, and the implantation is performed maskless with a narrowed width of about 0.15(4) μm and p=4soo; p
The SL implanted into the InP layer 6 expands a little inside, so that the width becomes about 0.2 μm. On the other hand, when injecting H, the degree of vacuum is 10 torr and the acceleration voltage is 20 to 30□. V
, driving depth 0.2~0.3μ, dose amount 10 ~
10 pieces/cm2, similarly without a mask, the width is about 0
．． Implantation is performed with a focus of 15 μm. In both cases, p-type 1nP layer 3 ('II: 2xL1
A value of about 5 x 10"6 cm"3 was obtained by the CV measurement method when the same amount was implanted in an area of I x 1 mm2 in 018 cm-3).

Further, FIG. 6 is a front sectional view of a semiconductor light emitting device 60 showing a modification of the device shown in FIG. 1, and FIG. 4 is an enlarged view of the optical waveguide portion thereof. Note that the same parts as those indicated in FIGS. 1 and 2 are indicated by the same symbols.

In the semiconductor light emitting device 60, the p-type G constituting the optical waveguide
The structure is different from the semiconductor light emitting device 20 in that an ion implantation portion is formed in the a1nAsP core layer 2, but
The same effects as the device 20 can be obtained.

Effects of the Invention As described above, according to the present invention, by utilizing the fact that the refractive index of a semiconductor material changes depending on the carrier concentration, the carrier concentration can be periodically changed by implanting ions into the surface of the optical waveguide. Since the ion implantation structure is designed to form a distributed reflector with a flat surface and ion implantation can be performed with high precision, it is possible to improve the periodicity.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention; FIG. 1 is a front sectional view of a semiconductor light emitting device, FIG. 2 is an enlarged view of the main part of chain 1, and FIG. 6 is another example of the semiconductor light emitting device. Front sectional view, 4th
The figure is an enlarged view of the main part of FIG. In the figure, 1 is a p-type 1nP substrate (first cladding layer), 2 is a p-type Ga1nAsP core layer (core layer with a higher refractive index than the first cladding layer), and 3 is a p-type 1nP layer (more than the core layer). (second cladding layer with a small refractive index), 4 is undoped Ga
1nAsP layer (active layer), 5 is an n-type 1nP layer, 6 is an ion implantation part, 7.8 is an electrode, and 9 is a distributed reflector. Patent applicant Fujitsu Limited Patent attorney Gobe Tamamushi (1 other person) (7)

Claims (1)

[Scope of Claims] t. A semiconductor light emitting device comprising a light emitting region and an optical waveguide, the semiconductor light emitting device comprising a distributed reflector in which the carrier concentration of the optical waveguide changes periodically. 2. A method for manufacturing a child conductor light emitting device, characterized in that periodic changes in carrier concentration are imparted to the surface of an optical waveguide by implanting ions at a predetermined pitch.