JPS63120491A - Semiconductor laser - Google Patents

Abstract

PURPOSE:To obtain a semiconductor laser wherein the oscillation threshold current is small and the reproducibility of characteristics is superior, by forming a current barrier layer composed of a thin semiconductor oxide film so as to neighbour to an active layer. CONSTITUTION:The title device is provided with the following; a clad layer 12 on a flat plate, a stripe type active layer 14 formed thereon, a current barrier layer 13 of a semiconductor oxide film neighbouring to an active layer 14 on the first clad layer 12, and a second clad layer 15 formed so as to neighbour to the side part and the upper part of the active layer 14. The side part of the active layer 14 contacts the current barrier layer 13 at the near side to the first clad layer 12, and contacts the second clad layer 15 at the more distant side than the first clad layer 12. For example, on an n-type GaAs substrate 10, the following are formed as shown in the figure: an n-type GaAs buffer layer 11, an n-type Al0.4Ga0.5As clad layer 12, a current barrier layer 13 of AlGaAs oxide film, a stripe-type active layer 14 of GaAs, a p-type Al0.4Ga0.5As second clad layer, etc.

Description

[Detailed description of the invention] (Industrial application field) This invention relates to a semiconductor laser.

(Conventional technology) Figure 2 shows a conventionally developed semiconductor laser.

There is an embedded semiconductor laser as shown (I Triple E Journal of Quantum Electronics z
(IEEE Journal of Quantum
Electronics, QE-16, 205, 1
980) ). The active layer 22 is an n-type cladding layer 21 .made of a semiconductor whose refractive index is 41% higher than that of the active layer 22 . P-type rad layer 23. Since it is surrounded by the buried layer 24 made of an n-type semiconductor, light is confined within the active layer and a stable laser oscillation state can be maintained.

(Problems to be Solved by the Invention) However, the semiconductor laser having the structure shown in FIG. 24
The crystallinity of the interface between the active layer 22 and the active layer 22 is poor, and the reproducibility of characteristics and high reliability cannot be obtained. Furthermore, this semiconductor laser had the disadvantage that current flows from the p-type rad layer 23 to the buried layer 24, increasing the oscillation threshold current.

An object of the present invention is to solve this problem and provide a semiconductor laser with a small oscillation threshold current and excellent reproducibility of characteristics.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the semiconductor laser provided by the present invention includes a flat first cladding layer and a first cladding layer formed on the first cladding layer. a) a live active layer, a current barrier layer formed of a semiconductor oxide film in a region adjacent to the active layer on the first cladding layer, and a current barrier layer formed adjacent to the sides and top of the active layer; a second cladding layer,
The side portions of the active layer are in contact with the current barrier layer on the side closer to the first cladding layer and in contact with the second cladding layer on the side farther from the first cladding layer.

(Function) In the semiconductor laser having the above structure, since the semiconductor oxide film is formed adjacent to the active layer, leakage current can be made very small. Further, the height of the active layer stripe is very low, about 0.17J171, and the crystal growth of the second cladding layer can be performed with good reproducibility.

(Example) Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a sectional view showing one embodiment of the present invention. In this example, a barrier layer (thickness 0.2 pPn) 1 made of n-type GaAs is placed on a semiconductor substrate 10 made of n-type GaAs.
1. A first cladding layer (thickness I Fin ) made of n-type An o , Ga, sAs (thickness I Fin ) 12 , An
Current barrier M made of GaAs oxide film (width 20 mm, thickness 0
13. Striped active layer made of GaAs (width 4 mm, thickness 0.0 mm) 14.

A second layer consisting of p-type An o , 4Ga6 , , As
Cladding layer (1 layer thick)15. Cap layer 16 made of p-type GaAq. and 5i0* membrane 17. p-electrode】8. It has a structure in which an n-electrode 19 is formed.

Semiconductor crystal growth was performed by molecular beam crystal growth.

First, a buffer layer 11, a first cladding layer 12. The active layer 13 is crystal-grown, and then the crystal-grown active layer 13 is formed into a strip-like shape with the first cladding layer 1.
Etching was performed until 2 appeared, and this was kept in an oxygen atmosphere to form a semiconductor oxide film 13. Subsequently, a second cladding M15. cap layer 1
6, and finally a 5ift film]7. p electric wA18
An r n electrode 19 was formed.

p-electrode 18. And the holes and electrons injected from the n-electrode 19 have a current barrier yf! The flow is obstructed by f13 and all of it flows into the active layer 14. Therefore, leakage current could be extremely reduced. Moreover, the thickness of the active layer 14 is 0.
1ρ, and the etching depth is only about 0.1ρ.
Since the current barrier layer 13 is also as thin as 0702, the crystal growth of the second cladding layer 15 can be performed on a substantially flat surface, and because of the knee, the crystal growth can be performed with good reproducibility. Depending on the growth conditions, the crystals on the current barrier layer 13 may become polycrystalline, but the same effect can be obtained in this case as well.

In this embodiment, an AflGaAs-based mixed crystal is used, but the present invention is not limited to this, and the present invention can be realized using other semiconductor mixed crystals such as an InAflGaAs-based mixed crystal.

(Effects of the Invention) According to the present invention, by forming a current barrier layer made of a thin semiconductor oxide film adjacent to the active layer, a semiconductor laser with a small oscillation threshold current and excellent reproducibility of characteristics can be obtained. Can be done.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, and FIG. 2 is a sectional view showing a conventional buried semiconductor laser. 10... Semiconductor substrate, 11... Buffer layer, 12
... first cladding layer, 13 ... current barrier layer, 14.
... Active layer, 15... Second cladding layer, 16... Cap layer, 17... Sin, film, 18... P electrode,
19...n electrode, 21...n-shaped rad layer, 22...
. . . active layer, 23 . . . p-type rad layer, 24 . . . buried layer.

Claims (1)

[Claims] a flat first cladding layer, a striped active layer formed on the first cladding layer, and a current barrier formed of a semiconductor oxide film in a region adjacent to the active layer on the first cladding layer. a second cladding layer formed adjacent to the sides and top of the active layer, the side of the active layer being in contact with the current barrier layer on the side closer to the first cladding layer, A semiconductor laser, wherein the semiconductor laser is in contact with the second cladding layer on a side farther from the first cladding layer.