JPS63202977A - Edge emission type semiconductor device - Google Patents

Abstract

PURPOSE:To transmit effectively light to an optical fibre and the like, by making a current injected from an electrode be effectively injected into an active layer by a first and a second block layer on the right and the left sides of the active layer, and making generated light be guided to and end surface by a first and a second clad layer, and the first and the second block layers. CONSTITUTION:An active layer 18 is completely buried in a stripe trench, on the right and the left sides of which first and second block layers 4 and 5 having energy band gap larger than the active layer 18 are arranged, so that the active layer 18 itself operates as an active region 1. Consequently, the injected carrier flows effectively into the active region 1, and does not diffuse toward the right and the left sides. Generated light is effectively guided to an end surface, by first and second clad layers 3 and 6 and first and second block layers 4 and 5. Thereby, a large light output can be transmitted in the case of coupling with an optical fibre, and the like.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an edge-emitting type semiconductor device that can efficiently transmit high optical output when coupled with, for example, an optical fiber.

[Conventional technology]

FIG. 3 shows, for example, Teeh, Digest of 4.
th Int.

Conf, on Integrated 0pt
ics and 0pticalF 1ber Com
communication, 29B2-4. (1983
) is a perspective view showing the structure of the conventional edge-emitting type semiconductor device shown in FIG.

In this figure, 1 is an active region made of InGaAsP, 2 is a substrate made of n-type InP, 8 is a p-side electrode, and 9 is an n-type substrate.
side electrode, 10 is an insulating film, 18 is an active layer made of InGaA and sP, 19 is a cladding layer made of p-type InP, 20
is a proton irradiation region, 21 is a contact layer made of p-type InGaAs, and 22 is a stripe length.

Next, the operation will be explained.

When a voltage is applied in the forward direction between the p-side electrode 8 and the n-side electrode 9, a current is injected into the active region 1, and when electrons and poles recombine in the active region 1, the active region 1 is formed. In
Light corresponding to the energy band gap of GaAsP is mainly emitted from the end face.

In this edge-emitting type semiconductor device, a stripe structure is provided in the p-side crystal in order to concentrate current in the active region 1, and proton irradiation regions 20 are provided on the left and right sides of the stripe structure.

Further, the stripe length 22 is less than half the length of the semiconductor device,
The structure is such that carriers are not injected into half of the active layer 18 so that no light is emitted 17 from the side opposite to the light emitting end face.

[Problem that the invention seeks to solve]

In the conventional edge-emitting type semiconductor device as described above, there is a distance from the stripe structure to the active layer 18, and even if the current is concentrated in the stripe structure, the current spreads laterally within the cladding layer 19. The active region 1 expands, and the width of light emitted from the end face becomes wider.

This is an important problem in light emitting devices for optical communication, and to solve this problem, conventionally it has been necessary to attach a spherical lens to the end face or use a spherical fiber.

This invention was made to solve these problems, and it increases the concentration of current in the active layer, suppresses the spread of the active region, and allows the light emitted from the end face to be suppressed without using a spherical lens or a spherical fiber. The purpose of this invention is to develop an edge-emitting type semiconductor device that can efficiently transmit data through optical fibers, etc.

[Means for solving problems]

An edge-emitting type semiconductor device according to the present invention includes a substrate of a first conductivity type having a groove formed in a light emission direction, and a first block of a second conductivity type formed in a portion of the substrate other than the groove. a second block layer of a first conductivity type formed on the first block layer, and a first conductivity layer formed from the bottom of the groove to the side surface of the first block layer or the second block layer. a first cladding layer of the mold; an active layer formed on the first cladding layer; and a second cladding layer of a second conductivity type formed on the active layer and the second block layer. ,
and a second conductivity type contact layer formed on the second cladding layer.

[Effect]

In this invention, the current injected from the electrode is efficiently injected into the active layer by the first and second blocking layers on the left and right sides of the active layer, and the generated light is transmitted between the first and second cladding layers and the second blocking layer. Embodiment FIG. 1 is a perspective view, not showing the structure, of an embodiment of the edge-emitting type semiconductor device of the present invention.

In this figure, the same symbols as in FIG. 3 indicate the same parts,
3 is a first cladding layer made of mouth-type InP, and 4 and 5 are first and second cladding layers made of p-type and n-type InP, respectively.
6 is a second cladding layer made of p-type InP, 7 is a contact layer made of p-type InGaAsP,
11 is the active region length.

The main feature of this invention is that active layer 18 and active region 1 are coincident.

Next, the operation will be explained.

When a voltage is applied in the forward direction between the p-side electrode 8 and the n-side electrode 9, a current is injected into the active region 1, and the light generated here is emitted from the end surface, as shown in the conventional example. Based on the same principle as type semiconductor devices.

In an edge-emitting type semiconductor device having a stripe structure, the width of the active region (emission diameter) is generally wider than the stripe width, but this is due to the current structure as well as the carriers injected into the active layer. This is because it diffuses laterally within the active layer.

However, in this invention, the active layer 18 is completely buried in the stripe groove, and the first and second blocking layers 4 and 5, which have a larger energy bandgap than the active layer 18, are placed on the left and right sides of the active layer 18. Layer 18 becomes active region 1 as it is.

Therefore, the injected carriers efficiently flow into the active region 1 and do not diffuse to the left or right.

Further, the generated light is efficiently guided to the end face by the first and second cladding layers 3.6 and the first and second blocking layers 4 and 5.

Therefore, the length of the active region 1 is increased (active region length 11).

Optimal light output to the optical fiber to be coupled can be obtained by controlling the width and thickness. For example, when using a single mode fiber with a core diameter of 10 μmφ, the active region length 11 is set to the length of the semiconductor device. Less than half, width 10μm
Hereinafter, the optimum bonding state can be obtained by setting the thickness to 0.2±0.1 μm.

FIG. 2 is a perspective view showing the structure of another embodiment of the invention.

In this figure, the same symbols as in Fig. 1 indicate the same parts,
12 is a substrate made of p-type nP, 13 is a first cladding layer made of p-type InP, 14.15 is a J-th and second block layer made of n-type and p-type InP, respectively, 1
6 is a second cladding layer made of n-type InP, and 17 is a contact layer made of n-type InGaAsP.

In the above embodiment, an n-type substrate was used and the active region length 11 was formed to be shorter than half the length of the semiconductor device. However, in this embodiment, after the growth of each layer, the active region 1 is After etching to a depth that reaches the substrate 12 made of p-type InP, and roughening the end surface appropriately, the n-side electrode 9 is formed on the concrete layer 17.

When forming the active region 1 using a p-type substrate in this way, it is sufficient to reverse all the conductivity types when forming the active region 1 using an n-type substrate. The second block layer 14 and the second block layer 15 are located above the second block layer 14 and adjacent to the second block layer 15 .

〔Effect of the invention〕

As described above, the present invention includes a substrate of a first conductivity type having a groove formed in the light emission direction, a first block layer of a second conductivity type formed in a portion of the substrate other than the groove,
A second block layer of the first conductivity type formed on this first block layer.
a first cladding layer of the first conductivity type formed from the bottom of the groove to the side surfaces of the first block layer or the second block layer; and an active layer formed on the first cladding layer. a second cladding layer of a second conductivity type formed on the active layer and on the second blocking layer;
and a contact layer of the second conductivity type formed on the cladding layer, current (carriers) can be efficiently injected into the active layer by the first and second blocking layers, and cladding layer and the first and second
The blocking layer guides light efficiently, and has the effect of transmitting high optical power when coupled to an optical fiber, for example.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing the structure of an embodiment of the edge-emitting semiconductor device of the present invention, FIG. 2 is a perspective view showing the structure of another embodiment of the invention, and FIG. 3 is a conventional edge-emitting type semiconductor device. FIG. 1 is a perspective view showing the structure of a semiconductor device. In the figure, 1 is an active region, 2 and 12 are substrates, and 3.13
1st Kula, Sodo layer, 4th, 14th block 1st layer,
5.15 is the second block layer, 6°16 is the second cladding layer, 7.17 is the contact layer, 8 is the p-side electrode, 9 is the n
10 is an insulating film, and 11 is an active region length. Note that the same reference numerals in each figure indicate corresponding parts. Agent Masuo Oiwa (2 others) (JO) Figure 1 Figure 2 Figure 3

Claims (4)

[Claims] (1) A substrate of a first conductivity type having a groove formed in the light emission direction, a first block layer of a second conductivity type formed in a portion other than the groove on this substrate, and a first block layer of a second conductivity type formed on the substrate other than the groove; a second block layer of a first conductivity type formed on the block layer; and a first block layer of a first conductivity type formed from the bottom of the groove to the side surface of the first block layer or the second block layer. a cladding layer, an active layer formed on the first cladding layer, a second cladding layer of a second conductivity type formed on the active layer and the second block layer, and a second cladding layer of a second conductivity type formed on the active layer and the second block layer; 1. An edge-emitting semiconductor device comprising a second conductivity type contact layer formed on a second cladding layer. (2) The edge-emitting type semiconductor device according to claim (1), wherein the groove is formed only on one end surface side of the substrate. (3) Claim No. 1 characterized in that a region on the substrate on one end surface side is removed by etching.
) The edge-emitting semiconductor device described in item 2. (4) The substrate is InP and the active layer is InGa with a crescent-shaped cross section.
Claim No. (1) characterized in that it is AsP.
The edge-emitting semiconductor device described in .