JPH027581A - Semiconductor light emitting device and manufacture thereof - Google Patents

Abstract

PURPOSE:To transmit an optical signal of many wavelengths through only one fiber with a simplified structure by arranging two or more of stripe-shaped semiconductor light emitting sections of different emission wavelengths on a straight line along a stripe axis so as to have a function of combining those wavelengths. CONSTITUTION:Semiconductor light emitting devices (semiconductor laser or semicon ductor light emitting diode) 2, 3, 4 including stripe-shaped semiconductor light emitting section on a common ground electrode 1 are aligned on a straight line and excited to emit light with two or more different wavelengths located on a straight line when viewed from the side of the laser having wider forbidden band. Hereby, a semiconduc tor light emitting device is constructed which emits an optical signal of a plurality of wavelengths and has a function of synthesizing of those wavelengths. Each semicon ductor light emitting device 2, 3, 4 includes a semiconductor active layer 6, that emits light, formed on an n-type, for example, one conductivity type semiconductor region 5, a p-type, for example, opposite conductivity type semiconductor region 7 formed on the layer 6, and an electrode 8 formed on the region 7. The semiconductor light emitting devices 2, 3, 4 have energy gaps E1, E2, E3, which satisfy the relation, E1<E2<E3, and emit the light of photon energies hnu1, hnu2, hnu3.

Description

[Detailed description of the invention] [IR required] To provide a semiconductor light emitting device capable of emitting light of multiple wavelengths, and capable of transmitting optical signals of multiple wavelengths to a single fiber with a simple configuration. For the purpose of the present invention, two or more striped semiconductor light emitting parts having different emission wavelengths are arranged in a straight line along the stripe axis, and the semiconductor light emitting parts are arranged in order from the narrowest forbidden band width to the largest forbidden band width. The configuration is such that light is extracted from the side with the larger band width.

[Industrial Field of Application] The present invention relates to a light emitting device, and particularly to a semiconductor light emitting device capable of emitting light with multiple wavelengths and a method for manufacturing the same.

[Prior Art] In optical communications, attempts have been made to expand the capacity of a communication path by transmitting optical signals of different wavelengths through one optical fiber. In this case, multiple wavelength lights from multiple optical signal sources are introduced into a single fiber using a multiplexer.

[Problems to be Solved by the Invention] When attempting to transmit optical signals of multiple wavelengths through a single fiber, the structures of the optical signal source and the multiplexer become complicated.

An object of the present invention is to provide a semiconductor light emitting device that can transmit optical signals of multiple wavelengths through a single fiber with a simple configuration.

Another object of the present invention is to provide an integrated semiconductor light emitting device capable of emitting optical signals of multiple wavelengths.

Furthermore, these semiconductor light emitting devices are difficult to manufacture and therefore difficult to use.

Another object of the present invention is to provide a semiconductor light emitting device capable of transmitting multi-wavelength optical signals, which can be manufactured by a simple method, and a method of manufacturing the same.

[Means for Solving the Problem] If the light emitting device itself is provided with a multiplexing function, the scale of the multiplexer can be reduced.

Therefore, two or more striped semiconductor light emitting parts having different emission wavelengths are arranged in a straight line along the stripe axis to form a semiconductor light emitting device having a multiplexing function.

Furthermore, it is possible to configure a semiconductor light emitting device in which a plurality of optical signal sources are integrated on one semiconductor substrate.

Further, by selectively subjecting a superlattice structure constituting a single or multiple quantum well structure to atmospheric heat treatment under different conditions, a semiconductor light-emitting device that emits light at a plurality of wavelengths can be constructed.

When integrated, processes such as optical axis alignment can be omitted. Furthermore, it becomes easy to downsize the device.

By selectively subjecting a superlattice structure constituting a single or multiple quantum well structure to atmospheric heat treatment under different conditions, it is possible to easily manufacture a semiconductor light emitting section that emits light at a plurality of wavelengths.

[Operation] The emission wavelength of a semiconductor light emitting device is determined by the forbidden band width of the semiconductor. Even if light with energy smaller than this forbidden band width is incident, the semiconductor will not absorb this light.

Since two or more striped semiconductor light emitting parts are arranged in a straight line along the stripe axis, two or more light emitting beams are generated on the same optical axis.

The semiconductor light emitting parts are arranged in order from the smallest forbidden band width to the largest forbidden band width, and light is extracted from the side with the larger forbidden band width, so that optical signals of a plurality of wavelengths can be extracted without substantially attenuating.

Two or more semiconductor light emitting parts [Embodiment 1] Semiconductors with different forbidden band widths are arranged on a straight line so that the forbidden band widths change monotonically (for example, in ascending order), and the semiconductor light emitting parts are caused to emit light, When viewed from the side with the larger forbidden band width, -2 on the straight line
More than two different wavelengths of light are available. As a result, a semiconductor light emitting device that emits optical signals at a plurality of wavelengths and has a multiplexing function can be obtained. A basic embodiment of the present invention will be described with reference to FIGS. 1A and 1B.

As shown in FIG. 1(A), a semiconductor light emitting device (for example, a semiconductor laser or a semiconductor light emitting diode) having a striped semiconductor light emitting section on a common ground electrode 1 2.3.
4 are arranged in a straight line, each semiconductor light emitting part! In 2.3.4, a semiconductor active layer 6 that emits light is formed on a semiconductor region 5 of one conductivity type, which is, for example, an n-type, and a semiconductor region 7 of an opposite conductivity type, which is, for example, a p-type, is formed thereon. T's are formed above it.

The semiconductor light emitting device 2.3.4 has energy gaps 1E 1 , E 2 , and E 3 that satisfy the relationship E 1 <E 2 <E 3 as shown in FIG. 1(B). The photon energies hν1, hν2, hν3
generates light. Since the energy gaps E2 and E3 of the semiconductor light emitting device 3.4 are larger than the energy gap E1 of the semiconductor light emitting device 2, the semiconductor light emitting section 'f13.4 is transparent to the light hv1. Also, a semiconductor light emitting device! Since the energy gap E3 of f4 is larger than the energy gap 1E2 of the semiconductor light emitting device 3, the semiconductor light emitting device 4 is transparent even to the light of hv2. Therefore, hν1, hν2, h
Light of ν3 is emitted.

In this way, two or more semiconductor light emitting sections can be constructed by arranging individual semiconductor light emitting devices.

In this case, the semiconductor light emitting device may be a semiconductor laser, a semiconductor light emitting diode, or another semiconductor light emitting device.

If two or more semiconductor light-emitting devices are monolithically integrated on one semiconductor substrate, two or more semiconductor light-emitting parts can be precisely arranged on a straight line using a mask pattern, and subsequent optical axis alignment can be made unnecessary. Furthermore, the device can be made smaller.

In this case, since there is one pair of end faces of the semiconductor on the optical axis, the light emitting part other than the longest wavelength light emitting part does not require a cavity.
It is better to set it to 4.

FIG. 2 shows an example in which two semiconductor light emitting diodes are formed on one semiconductor substrate.

Two light emitting diodes are monolithically integrated on a semiconductor substrate 10. By performing selective growth using MOCVD, LPE, etc., selective etching, etc., two semiconductor light emitting diodes with different forbidden band widths are formed on one substrate. formed n
The type layer 11, the active layer 13, and the P-type layer 15 constitute the left-hand light emitting diode, and the n-type layer 12 on the right surface of the n-type substrate 10
, active layer 14, and p-type layer 16 form the diode on the right. Above the p-type layer 15.16 is a pffll electric f! 17.
18 are formed. An n-side electrode 19 is formed on the lower surface of the substrate 10. Such a structure is, for example,
It is manufactured by masking the right part and selectively growing the left part, then masking the left part and selectively growing the right part. First, the entire surface is grown, the left half is removed by selective etching, and then the left side can be selectively grown.Each light emitting diode has a different emission wavelength, and one with a similar lattice constant is selected.For example, as a substrate. An InP substrate is used, and InGaAsP diodes having different compositions are formed on the substrate.

Next, a simpler example of the manufacturing process is shown in Figure 3 (A).
, (B) and (C).

Referring to FIG. 3(A), an n-type layer I is formed on an n-type substrate 20.
Ga 6.5 As layer 21, multi-fIL quantum well horizontal 0.5 structure 22, p-type AI Ga As layer 25, p-type 0
．． 5 0.5 GaAs layer 26 is grown. The multiple quantum well structure 22 is
For example, 5 layers of GaAs 23 with a thickness of 80 and a thickness of 12
It is composed of an alternately laminated superlattice structure of 24 4-layer AI GaAsO, 30,7 layers. By selectively performing heat treatment under different conditions on the superlattice structure constituting the multi-quantum well structure, light-emitting layers with different emission wavelengths are formed.

FIG. 4 shows an example of a change in emission wavelength depending on heat treatment conditions of a GaAs/AlGaAs multiple quantum well.

The horizontal axis shows the As4 pressure, and the vertical axis shows the emission wavelength.

The heat treatment temperature is 850° C. and the treatment time is 2.5 hours.

As As4 pressure is increased, the emission wavelength gradually becomes longer (
(low energy), and reaches its longest wavelength at approximately 100 Torr. When the As pressure is further increased, the emission wavelength becomes shorter again.

The emission wavelength changes depending on the mask provided on the surface.

By selectively using 5i02, Si3N4, and Al3N4 as a mask, the emission wavelength is selectively changed.

In the case of a GaAs/AlGaAs multiple single-well structure, the emission wavelength can be varied, for example, in the range of 760 to 835 nm.6 By selectively using a mask, the emission wavelength can be selectively changed/changed. can.

In FIG. 3(A), 5i0 is selectively added to the surface of the structure.
We have 2 masks. In other words, the upper surface is area-engineered, ■
S i O2M! A is formed.

This structure is subjected to atmospheric heat treatment at about 850° C. for about 2.5 hours while applying an As4 pressure of about 100 Torr.

After this atmospheric heat treatment, the emission wavelength of region I is approximately 83 oni, while the emission wavelength of region (3) changes to approximately 750 n1. After that, as shown in Fig. 3(B), Z
Zn is diffused to form a Zn diffusion region 28 to form light emitting stripes. Furthermore, area 1. Protons are implanted into the boundary of II to form an isolation region 29 to provide electrical insulation between regions (1) and (2).

Furthermore, as shown in FIG. 3(C), A u
The n-side electrode 30 of G e / A u is placed in region 1. I[
pl of A u / Z n / A u respectively! I
! Form I electric i31.32. As a result, multi-wavelength light emission of 830 nm and 750 nm can be obtained from the front side of the device in the figure. These emitted beams are combined on the same optical axis and can be controlled separately.

In this way, by dividing the semiconductor surface into multiple regions, changing the mask structure (including no mask) for each region, and performing heat treatment, it is much easier to create integrated semiconductors that emit light at multiple wavelengths than by selective growth. A light emitting device can be realized.

[Effect] A multi-wavelength light emitting semiconductor light emitting device having a multiplexing function can be obtained.

When integrated on a single substrate, further miniaturization is possible, and optical axis alignment can be performed using a mask pattern.

When using a single or multiple quantum well structure in which the emission wavelength is selectively controlled by heat treatment under different conditions, the manufacturing process is also simple.

[Brief explanation of the drawing]

1(A) and (B) are a schematic perspective view and a schematic band diadem showing a basic embodiment of the present invention, FIG. 2 is a sectional view showing an embodiment of a monolithic structure of the present invention, and FIG. 3(A) ), (B), and (C) are cross-sectional views for explaining other embodiments of the present invention, and FIG. 4 is a graph for explaining heat treatment performed on the structure of FIG. 3(A). In the figure, 2.3.4 common electrode semiconductor light emitting section 1 conductivity type region active layer other conductivity type regions 11, 12 13.14 15, 16 17, 18 31, 32 electrode n-type substrate n-type region active layer p-type head Region electrode n-type GaAs substrate n-type AlGaAs layer multiple quantum well layer GaAs well layer AlGaAs barrier layer n-type AlGaAs layer P-type GaAs layer 5in2 mask Z rl diffusion region proton implantation isolation region A u G e / A u n (111 Electrode A u
/ Z n / Au basic example for p-side electrode company Fig. 1 (A) AuGe/Au nmJ@5z t-filled example Fig. 3

Claims (4)

[Claims] (1) Two or more striped semiconductor light emitting parts (2, 3, 4) having different emission wavelengths are arranged in a straight line along the stripe axis, and the semiconductor light emitting parts have a forbidden band width (E_1, E_2, E_3).
) are arranged in order from smallest to largest, and light is extracted from the side with the largest forbidden band width. (2) The two or more striped semiconductor light emitting parts are
2. A semiconductor light emitting device according to claim 1, characterized in that it is monolithically integrated on one semiconductor substrate (10, 20). (3) The two or more striped semiconductor light emitting parts are
2. The semiconductor light emitting device according to claim 1, wherein the semiconductor light emitting device has single or multiple quantum well structures (22) of the same configuration that are selectively subjected to atmospheric heat treatment under different conditions. (4) A step of forming a superlattice structure constituting a single or multiple quantum well structure on a semiconductor substrate, a step of selectively forming a mask on the surface, and a step of forming a mask under the mask by heat treatment in an atmosphere. A semiconductor light emitting device comprising the steps of: selectively subjecting a superlattice structure to atmospheric heat treatment under different conditions; and forming a plurality of striped semiconductor light emitting parts by penetrating the region subjected to atmospheric heat treatment under different conditions. Production method.