JPH06224469A - Semiconductor light emitting device - Google Patents

Abstract

(57) [Summary] [Structure] An array of LEDs 5 is provided on a substrate 1, and a reflection wall 10 for reflecting light emitted from the side surface of each LED 5 is provided between adjacent LEDs 5. Since the light emitted from the side surface of each LED 5 is reflected by the reflection wall 10, the adjacent LEDs
There is no reflection at 5. [Effect] For example, when it is used as a light source for exposure of an electrophotographic photosensitive drum, blurring of an image can be prevented and a sharp image can be obtained, and the light utilization efficiency is increased and the light amount is increased.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor light emitting device having an LED array on a substrate, and is used as a light source for exposing a photosensitive drum of a page printer, for example.

[0002]

2. Description of the Related Art LEDs on a substrate 100 as shown in FIG.
A semiconductor light emitting device having an array of 101 is used as a light source for exposing a photosensitive drum of a page printer, and each L
It has been proposed to form a dot corresponding to each LED 101 as a latent image on the photosensitive drum by light emitted from the light emitting surface 101a on the upper side in the figure of the ED 101 as shown by the solid line arrow in the figure.

[0003]

However, each LED 10
Light is emitted from No. 1 not only from the light emitting surface 101a but also from the side surface 101b as indicated by a dashed arrow in the figure, and the light is reflected by the side surface 101b of the adjacent LED 101. Therefore, for example, even if only the central LED 101 in the drawing emits light, the LEDs 10 on both sides of the LED 10
It seems that even the end portion of 1 emits light, and the outline of dots formed as a latent image on the photosensitive drum becomes unclear, which causes blurring of the electrophotographic image. In addition, each LED 101
There is a problem that the utilization efficiency of the light emitted from is low.

It is an object of the present invention to provide a semiconductor light emitting device which can solve the above problems of the prior art.

[0005]

SUMMARY OF THE INVENTION The present invention provides LE on a substrate.
A semiconductor light emitting device including a D array is characterized in that a reflection wall for light emitted from a side surface of each LED is provided between adjacent LEDs.

[0006]

According to the structure of the present invention, the light emitted from the side surface of each LED is reflected by the reflection wall provided between the adjacent LEDs and is not reflected by the adjacent LEDs.

[0007]

Embodiments of the present invention will be described below with reference to the drawings.

The semiconductor light emitting device 4 shown in FIG. 2 has an array of a plurality of mesa-shaped LEDs 5 formed in rows on one main surface side of the silicon substrate 1 and reflections formed between adjacent LEDs 5. And a wall 10.

A method of manufacturing the semiconductor light emitting device 4 will be described with reference to FIGS.
It will be described with reference to FIG.

First, as shown in FIG. 3, silicon oxide films 2a and 2b are formed on the entire surface of one main surface 1a and the other main surface 1b of a silicon substrate 1 by a thermal oxidation method. For example, the silicon substrate 1 may be oxygen (O ₂ ) at 1100 ° C to 1150 ° C.
By oxidizing in an atmosphere for about 60 minutes, the silicon oxide films 2a and 2b having a thickness of 1500Å to 10000Å
To form.

Next, as shown in FIG. 4, a part of the silicon oxide film 2a formed on the one main surface 1a of the silicon substrate 1 is removed by photolithography into a strip shape.
The silicon oxide film 2a formed on the one main surface 1a is used as an insulating mask.

Next, as shown in FIG. 5, a semiconductor crystal of III-V group or II-VI group is formed on the strip-shaped silicon substrate portion selected by the mask 2a, for example, metal organic vapor phase epitaxy (MOCVD) or Molecular beam epitaxy (MBE)
To grow the epitaxial layer 3. The epitaxial layer 3 is made of, for example, gallium arsenide (GaA).
s), gallium arsenide phosphide (GaAsP), gallium phosphide (GaP), and other buffer layers 3a, and gallium arsenide and aluminum gallium arsenide (AlGaA).
s), indium gallium arsenide (InGaAs), gallium arsenide phosphide, and the like, which are n-type semiconductor layers 3b, p-type semiconductor layers 3c, and heavily-doped p ^{+ -type} semiconductor layers 3d.

Next, in order to remove the epitaxial layer 3 that has grown in the shape of a strip, leaving a portion that will become the LED 5 and a portion that will become the reflection wall 10, as shown in FIG.
5, a resist 11 is formed on a portion corresponding to 5 and a portion corresponding to the reflection wall 10, and thereafter, etching is performed as shown in (2) of FIG. 6, and then, as shown in (3) of FIG. The resist 11 is removed. Since the etching progresses not only in the depth direction but also in the lateral direction, the width of the resist 11 is at least twice the etching depth. As the etching liquid, a mixture of general sulfuric acid, hydrogen peroxide and water can be used. Since the etching rate differs depending on the plane orientation, the upper side surfaces of the LEDs 5 facing each other are reverse mesa portions 5 '.

Next, as shown in FIG. 7, the LED 5 is covered with a protective film 9, and electrodes 6a and 6b are connected to the p ^{+ type} semiconductor layer 3d and the other main surface 1b of the substrate 1. The electrode 6a,
For 6b, for example, chrome gold (CrAu) is used. Each LED 5 has, for example, a mesa shape with a rectangular shape in plan view of about 60 μm × 50 μm, is arranged at a pitch of about 84 μm, and the reflection wall 10 is positioned at the center between the pitches.

According to the above structure, as shown in FIG. 1, the light emitted from the side surface 5b of each LED 5 is reflected by the reflection wall 10 as indicated by the broken line arrow in the figure, so that the adjacent LEs are adjacent to each other.
It does not reflect at D5, and can be used together with the light emitted from the light emitting surface 5a on the upper side of each LED 5 in the figure as indicated by the solid line arrow in the figure.

The present invention is not limited to the above embodiment. For example, the substrate is not limited to SILICON
You may use aAs etc. Further, a metal having a high reflectance may be vapor-deposited on the reflection wall 10.

[0017]

According to the semiconductor light emitting device of the present invention, each L
Since it is possible to prevent the light emitted from the ED from being reflected by the adjacent LED and narrow down each light emitting region, for example, when it is used as an exposure light source of an electrophotographic photosensitive drum, blurring of an image is prevented and sharpness is reduced. It is possible to obtain a clear image, and the light utilization efficiency is increased, and the light amount is increased.

[Brief description of drawings]

FIG. 1 is a structural explanatory view of a semiconductor light emitting device according to an embodiment of the present invention.

FIG. 2 is a perspective view of a semiconductor light emitting device according to an embodiment of the present invention.

FIG. 3 is a first process for manufacturing a semiconductor light emitting device according to an embodiment of the present invention.
Illustration of process

FIG. 4 is a plan view of an insulating mask for manufacturing a semiconductor light emitting device according to an embodiment of the present invention.

FIG. 5 is a sectional view of the semiconductor light emitting device according to the embodiment of the present invention during manufacture.

FIG. 6 is an explanatory diagram of an etching process of a semiconductor light emitting device according to an embodiment of the present invention.

FIG. 7 is a diagram showing a cross-sectional structure of a semiconductor light emitting device according to an embodiment of the present invention.

FIG. 8 is a structural explanatory view of a conventional semiconductor light emitting device.

[Explanation of symbols]

 1 substrate 5 LED 10 reflective wall

Claims (1)

[Claims] 1. A semiconductor light-emitting device comprising an LED array on a substrate, wherein reflective walls for light emitted from the side surface of each LED are provided between adjacent LEDs.