JPH01205479A - End surface light emitting type semiconductor light emitting device - Google Patents

Abstract

PURPOSE:To improve temperature characteristics of light output and light leading-out efficiency, by making both of the side surfaces of a current injection region not paral lel, and constituting their inclination angles with respect to the light emitting surface in the range of 90 deg. and more and less than 90 deg.+ a specified value. CONSTITUTION:The title semiconductor light emitting diode of end surface light emit ting type is provided with a stripe type current injection region 6. Both side surfaces of the current injection region 6 are not parallel, and the inclination angle theta(=90 deg.+x) with respect to a light emitting surface 12 is 95 deg.. As the distance from the light emit ting surface 12 increases, the interval between both side surfaces extends. As compared with the conventional current injection region, the angle is increased by 5 deg.. As a result, the lights generated in the two extended area parts are guided and enter the same light emitting surface 12 at an angle equal to or less than 95 deg., which are added each other and radiated outward. Since the area is large, the temperature dependency of the radiated light is little as compared with the conventional E/E LED. Further, the light emitting surface 12 and back surfaces 13, 14 do not become parallel on any surface. By this structure, the generation of stimulated emission light is restrained, and temperature dependency of light is decreased.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to an edge-emitting semiconductor light-emitting device.

However, semiconductor lasers are excluded.

[Conventional technology]

Conventional edge-emitting semiconductor light emitting diode (hereinafter referred to as E/E)
LED) as shown in Figure 3 (al ~ (CI K)
The current injection region 6 had a long sword-shaped stripe shape.

[Problem to be solved by the invention]

The conventional E/E LED described above contains more stimulated emission light than a full-emission type semiconductor light emitting diode (hereinafter referred to as S/E i, ED) in its emitted light component. That is S/
This is because, compared to ELEDs, E/E LEDs have a longer distance for light to be guided through their active layer.

In general, stimulated emission light has a stronger temperature dependence than spontaneous emission light, so it contains a large amount of stimulated emission light as a component of the synchrotron radiation.
/E LED has stronger temperature dependence of emitted light than S/E LED.

Currently, methods for reducing the temperature dependence of emitted light include: (1) shortening the lifetime of carriers (by doping the light emitting part with carriers, etc.);

(2) Lower the current density (increase the area sound of the current injection region).

These two methods are used, but in either case, the optical output is small.

Finally, υ reduces the temperature dependence of the synchrotron radiation and at the same time increases the
J" The drawback is that it is not possible to make the sword larger.

[Means to solve the problem]

The edge-emitting semiconductor light-emitting device of the present invention is an edge-emitting semiconductor light-emitting device in which a striped current injection region is provided on a pellet in which a semiconductor heterojunction structure in which active N is sandwiched between cladding layers with a large refractive index is laminated on a semiconductor substrate. In a type semiconductor light emitting device, the angle θ between the non-parallel side surfaces of the current injection region and the light exit surface, the radiation angle α of the light, and the refractive index of the cladding layer 'f! :n, and the distance between the side surfaces on both sides increases as the distance from the light exit surface increases.

〔Example〕

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

FIG. 1 is a top view of a pellet showing a first embodiment of the present invention. Note that the shapes other than the current injection region are as shown in FIG. 3 (al.
This is the same as the conventional example shown in ~(C).

In this embodiment, a p+ type In-○a is formed on an n-type 1nP substrate 1.
AsP active layer 3 ((λg = 1.3 μm)?, 7 A stripe-like structure is formed on a stacked pellet of a semiconductor heterojunction structure sandwiched between soft cladding N (n-type J: nP/i2.4) with a soft refractive index. In an edge-emitting semiconductor light emitting diode provided with a current injection region 6, the angle θ (=90°+X) that the side surfaces on both sides of the current injection region 6 are non-parallel and form with the light exit surface 12 is
is 95°, and the distance between the side surfaces on both sides increases as the distance from the light exit surface 12 increases.

The size of the pellet is 300 μm x 200 μm long sword, the length of the current injection region is 165 μm, and the thickness of the active layer is 0.1 μm. In general, the light emission angle of an E/E LED is about 20° on one side, and if the refractive index of InP is 3.5 and that of air is 1, then 1 sin 20° = 3,5 sin x, x =
Since the angle is 5.5 degrees, light guided from the light exit surface at an angle of 95.5 degrees or less will be radiated to the outside from the light exit surface.

In this example, the angle made by the tsuta shown in Fig. 1 is 9
It was set to 5°. The angle is 5° compared to the conventional current injection region.
Due to the expansion, light is emitted in the two expanded areas (two shaded areas in the figure), and the guided light is directed to the same light exit surface 1.
2 at an angle of 95° or less, they are added together at this light output section and emitted to the outside. Moreover, since the area of the current injection region is larger than that of the conventional E/E LED, the temperature dependence of the emitted light is small.

Furthermore, in the present invention, in order to efficiently guide the light emitted from the current injection region, the side surface is made of a metal with high reflectance (Au).
) is deposited on the x-povation film 7. Moreover, when the rear surface of the light emitting surface 12 becomes a surface parallel to the light emitting surface as in the conventional case, the light reflected from this surface is directed back to the light emitting surface and is guided by the waveguide. In order to suppress this, there is a technique of etching diagonally, but in addition to this, the present invention has a structure in which the light emitting part 12 and the rear surface 13° 14 are not parallel even on the same plane. , suppresses the generation of stimulated emission light and reduces the temperature dependence of light.

FIG. 2 is a top view of a pellet showing a second embodiment of the present invention. This example is also a long wavelength band E/E LED formed on an InP substrate. Its dimensions are the same as in the first embodiment except that the length of the current injection region is 300 μm. In addition, the light emitting surface 12 and its two side surfaces are brought into contact with each other at an angle of 95° as in the first embodiment, and the area of the current injection region 6 is expanded, and the light emitted from the expanded portion is The light can be emitted from the same light exit surface 12. Furthermore, the current injection region 6 is made to extend across the entire length of the pellet, and the surface 8tk of the current injection region 6 is made wider than in the first embodiment.

In addition to this, in this embodiment, light exit surfaces 15 and 16 were also provided behind the light exit surface 12. However, as described in the first embodiment, the light emitted from this area has a light emitting area of ±5.5 degrees from the normal direction of the light emitting surface.
The light output is limited to the area (shaded area in the figure), and the light output is weaker than that of the front light exit surface 12. Therefore, this light output ffi
] The light emitted from 15 and 16 can be used as monitor light.

Next, the rear surfaces 13 and 14 of the light emitting surface 12 are structured so that no plane is parallel vC to the light emitting surface 12, as in the first embodiment.

〔Effect of the invention〕

As explained above, the present invention eliminates the parallel parts of the optical resonator structure formed by the light emitting surface and the facing surface of the edge-emitting semiconductor light emitting device, and the surface I of the current injection region.
Rk wide < shi, while reducing the temperature dependence of the emitted light, the two sides of the light exit surface are brought into contact with an angle less than the total reflection angle calculated from the radiation angle of the light, and the conventional 90"
The structure in which the light is held and brought into contact has the effect of maximizing the thickness of the light emitting area emitted to the outside and increasing its light output.

It should be noted that the present invention is not limited to the shape of the current injection region shown in the embodiments, and includes (1) a clause in which the opposite side of the light exit surface does not constitute a plane parallel to the light exit surface; (2) a light exit surface; side surface is at an angle of 90° or more with the light emitting surface, 90°
The optical output,
This improves the light extraction efficiency and the temperature characteristics of light output.

[Brief explanation of the drawing]

FIGS. 1 and 2 respectively show the first embodiment of the present invention. FIG. 3(a) is a top view of a pellet showing the second example. (bi, (cl) are top views of pellets showing conventional examples. They are a front view and a cross-sectional view. 1... n-type InP substrate, 2... n-type I
nP layer, 3...p+ type InGaAsP active layer, 4...p type InP cladding layer, 5...
-p-type InGaAsP cap layer, 6... current injection region, 7... passivation film, 8...
...Piltl electrode, 9...N side electrode, 1
0...Groove, 11...Contact window, 1
2...Light exit surface, 13 degrees 14...Opposite side of light exit surface, 15.16...Monitor light exit surface. Agent Patent Attorney Oto Uchihara Figure 1 Figure 2

Claims (1)

[Claims] In an edge-emitting semiconductor light-emitting device in which a striped current injection region is provided in a pellet in which a semiconductor heterojunction structure in which an active layer is sandwiched between cladding layers with a large refractive index is laminated on a semiconductor substrate. , the angle θ between the nonparallel side surfaces of the current injection region and the light exit surface is 90°<θ≦90°+Sin＾−＾1, where α is the radiation angle of light and n is the refractive index of the cladding layer. (sin α/n)
An edge-emitting semiconductor light-emitting device characterized in that the distance between the side surfaces on both sides increases as the distance from the light exit surface increases.