JPS62190886A - semiconductor laser equipment - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application J This invention relates to a semiconductor laser device, and in particular to a long wavelength band SCH (5 separate Confine
ment Heterostructure) It is a semiconductor and has one de-Kpl@.

[Prior Art] Conventionally, an SCH semi-dedicated laser consists of three semiconductors as basic components: an active layer semiconductor having a forbidden band width necessary to obtain a predetermined oscillation wavelength, and a lattice matching with the active layer semiconductor. It satisfies the condition and has a forbidden band width of 4; it consists of an optical waveguide layer semiconductor and a cladding layer semiconductor with a much smaller refractive index (Casey & Pansh, Hete
rostructure La5ers, 1978
.

Academic Press) o When manufacturing a semiconductor laser having a predetermined oscillation antilong band, given the substrate material, it is necessary to match the lattice constant with the substrate material.
If the dimension of the mixed crystal semiconductor is as low as 3 or more, there is little omniscience in the selection of the forbidden band width.On the other hand, if the dimension of the mixed crystal semiconductor is 4 or more, there is omniscience in the selection of the forbidden band width, but there is little omniscience in the selection of the forbidden band width. There is a general difficulty that compositional control of mixed crystal semiconductors is not easy.

A conventional long wavelength band SCH semiconductor laser having a wavelength range of 1.3 to 7.6 μm with small transmission loss through silica-based optical fiber used in optical communications uses InP as a substrate and has the configuration shown in Fig. 2. There is. In Figure 2, (1)
is a metal electrode, (2) is an InP substrate of the first conductivity type, and (3
) is the cladding layer of the first conductivity type, (4) is the undoped or first optical four-wave layer of the first conductivity type, (5) is the active layer, (
6) is an undoped or second conductivity type @2 optical equal wave layer,
(7) is a cladding layer of a second conductivity type, (8) is a contact layer of a second conductivity type, and (9) is a conductive layer. Here, the basic components of the SCH semiconductor laser are the active layer (5), the optical waveguide layer (4) (6), and the cladding layer (3).
] (1-XA5yP of three types of semiconductors corresponding to 7J
It is composed of a quaternary or more mixed crystal semiconductor such as t-yl.

[Problems to be Solved by the Invention] Since the conventional semiconductor laser device is constructed as described above, in order to satisfy the lattice matching condition, an active layer (5) composed of a quaternary mixed crystal semiconductor and an optical waveguide are used. Layer (4) (6)
The mixed crystal composition of any one of the cladding layers (3) and (7) must be slightly changed, and in conventional liquid phase epitaxial formation, the composition may be disordered due to melt mixing, and the hetero-interface There were problems such as deterioration of the Furthermore, even when vapor phase epitaxial growth is used, multi-component mixed crystal semiconductors require more precise compositional control of more constituent elements, so there is a problem in reproducibility and yield.

This invention was made in order to solve the above-mentioned problems, and without using a quaternary or higher mixed crystal semiconductor,
By using only two types of ternary mixed crystal semiconductors and using a superlattice or quantum well structure,
The object of the present invention is to easily obtain a μm band SCH semiconductor laser device.

[Means for Solving the Problems J] The semiconductor laser device according to the present invention includes quaternary mixed crystal semiconductor devices nxGayA11-z-yAs, ■nxGa1-X
Instead of using A a 7P ly, a ternary mixed crystal semiconductor 1n0.53Ga0.47 lattice-matched to InP
Using only As, In0.52Al0.48As,
In0.530aL), 47As and EngnU, 52Al0
．． A laminated structure made of 48As is used for the optical waveguide layer.

[Function] In this invention, the three basic semiconductor components of the semiconductor laser device are In0.53G which is lattice matched to InP.
It is composed of a0.47As, ■no, 52Alo, 48As, and a superlattice or quantum well structure in which they are stacked alternately, and only a ternary mixed crystal semiconductor is used, making the manufacturing method and 5CI (structural combinations easy). , the yield, reproducibility, and performance of the device are improved. (30) is an In0.52Al0.48A semiconductor substrate provided on this semiconductor substrate (20).
A first cladding layer (40) of the first conductivity type consisting of S is provided on this first cladding layer (2υ) and has a larger forbidden band width and a smaller refractive index than the first cladding layer (30). This first optical waveguide layer (4(+) is a quantum well "layer" is a 0.53Ga0.47As layer (10U) and a barrier layer. 0.48As layer (11
0) are alternately laminated with the same film thickness in a superlattice or cell well structure. (50) is In01 provided on the first optical waveguide layer (40) and having a larger forbidden band width and a smaller refractive index than the optical waveguide layer (40).
A non-doped or second conductivity type active layer (60) made of 52Ga0.47As is a second conductive layer (50) having approximately the same forbidden band width and refractive index as the optical waveguide layer (40). This second optical waveguide layer (60) is a two-conductivity type or non-doped second optical waveguide layer, and has the same structure as the first optical waveguide layer (40). (70) is provided on the second optical waveguide layer (60) and has approximately the same forbidden band width and refractive index as the first cladding layer (20).
The second of the second isoelectric type consisting of n0.52A40.48As
The cladding layer (80) is this second cladding layer (70)
A contact layer (90) made of In0.53Ga0.47As provided on the contact layer (80),
Gold fIj4 electrodes were provided at the top.

In the semiconductor laser device configured as described above, only two types of ternary mixed crystal semiconductors are used without using a quaternary mixed crystal semiconductor, and the three basic semiconductor components of the SCH semicircular body laser are I am getting . , E-book SCH semiconductor, the quantum well layer (to
o) Thickness lzk and barrier layer (11(1)IIIMIBf
:, quantum size effect (R, Dingle, Festk
orperprobleme edited by H
%J, Queisaer%Pergamon-V
ieweg, 1975, V o 1, XV +
P 21 ) occurs, if f<, then 1111
I band width is In0.53Ga0.47As (Eg~0
．． 8eV) and In0.52Al0.48As (E
g to 1.5 eV).

According to the results of quantum level calculation using the Kroenig-Benny model, if a value of about 20A is adopted as lz,
It can be seen that the difference in forbidden band width of 0.2 eV required for functioning as an SCH semiconductor laser can be easily obtained.

Moreover, the refractive index in the optical waveguide layer (40) (60) is
In0.53Gao, 47As layer (100) and In0.
52Al0.48As layer (IILI) is approximated by the average composition (/B/(/Z+7B)) K of the laminated structure consisting of In0.53Ga0.47As and In0.53Ga0.47As.
It can be set to an intermediate value between 52 Ga and 0.48 ribs.

As described above, instead of using a quaternary mixed crystal semiconductor that is lattice-matched to InP, In0.53Ga0.47As and In0.52Al0.48As, which are ternary mixed crystal semiconductors that are lattice-matched to InP, are used. By using a superlattice or quantum well structure, the 1.3-1.6 μm long wavelength band 5C can be achieved while ensuring the freedom to select the forbidden band width and refractive index.
I (active layer (SO) necessary to construct a semiconductor laser
), optical waveguide layers (40) (60) can be made, and it is possible to provide an advantageous method for manufacturing E-SCH semiconductors.

In the above embodiment, the optical waveguide layer (40) (60) used a superlattice or quantum valve 7'' structure consisting exclusively of two types of ternary mixed crystals listed in E. If it is necessary to select the laser oscillation f-length in the range of 1.3 to 1.6 pa depending on the required a performance of the element, the well structure can also be used for the active layer (5o) with I2T performance. In this case, the active layer (50) and the optical waveguide layer (40) (60)
The quantum co-F layer lz and the barrier layer 1Ht are selected between the acute layer (50) and the optical waveguide layer (4 (1) (6υ
), the refractive index can be set so that it increases in the order of the cladding layer, and conversely, the refractive index decreases.

[Effects of the Invention] As described above, according to the present invention, ternary mixed crystal semiconductors that are lattice-matched to InP, namely In0.53Ga0.47As and In0.52A, are used instead of the quaternary mixed crystal semiconductor.
Since the SCH semiconductor in the 1.3 to 1.6 μm band was constructed using a superlattice or quantum well structure made of 0.48 As, the fabrication of the SCH semiconductor shown in E is easy and has excellent reproducibility and yield. This has the effect of providing a long wavelength band SCH semi-dedicated laser device.

[Brief explanation of drawings]

FIG. 1 is a diagram showing the structure of a 5CI (semiconductor laser) according to an embodiment of the present invention, and FIG. 2 is a diagram showing the structure of a conventional 5CFI semiconductor laser. In the figure, (20) is an InP substrate; (3o) and (7o)
il-1′In0. ．． 52Al0.48As cladding layer, (4o) and (6o) are optical waveguide layers, (5 is active W,
(80) is an In0.53Ga0.47As tD contact layer, (100) is a t-well layer, and (110) is a barrier layer. Note that the same reference numerals in the drawings indicate the same or four equivalent parts.

Claims (3)

[Claims] (1) In0.
a first conductivity type cladding layer of 52Al0.48As; a non-doped or second conductivity type cladding layer provided on the first conductivity type cladding layer and having a larger forbidden band width and a lower refractive index than the first conductivity type cladding layer; an active layer, a second layer of In0.52Al0.48As having the same forbidden band width and refractive index as the first conductivity type cladding layer provided on the active layer;
a conductive type clad layer, which is provided between the first conductive type clad layer and the active layer or between the second conductive type clad layer and the active layer, and is connected to the first and second conductive type clad layers; In0.53G has a forbidden band width and refractive index intermediate to that of the active layer, and is lattice matched to the InP substrate.
an optical waveguide layer configured by alternately stacking quantum well layers made of a0.47As and barrier layers made of In0.52Al0.48As that are lattice-matched to the InP substrate; on the second conductivity type cladding layer; A semiconductor laser device comprising a second conductivity type contact layer provided in the semiconductor laser device. (2) The semiconductor laser device according to claim 1, wherein the active layer is made of In0.53Ga0.47As. (3) The active layer is made of In0.5 which is lattice matched to InP.
A semiconductor laser device according to claim 1, characterized in that quantum well layers made of 3Ga0.47As and barrier layers made of In0.52Al0.48As lattice-matched to Inp are laminated alternately. .