JPH05206500A - Photoelectric conversion module - Google Patents

Abstract

PURPOSE:To provide a photoelectric conversion module which is capable of carrying out more efficient photoelectric conversion. CONSTITUTION:Four light receiving devices (light receiving device group 3) are installed in parallel to each other on a light receiving plate to receive light from an optical fiber 1 in a photoelectric conversion module 2. Each of the light receiving devices are made of silicon and the depth of p-n junction is different from each other. The light having a number of wavelength components reach each light receiving device from the optical fiber 1 and it is converted into electricity per wavelength component in each light receiving device.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photoelectric conversion module, and more particularly to a photoelectric conversion module for converting light having many wavelength components into an electric signal.

[0002]

2. Description of the Related Art Conventionally, a semiconductor light receiving element has been disclosed in Japanese Patent Laid-Open No. 2-5.
It is disclosed in Japanese Patent No. 0487. This is to stack a plurality of layers having different bandgap energies in a direction perpendicular to the light receiving surface (depth direction) to selectively photoelectrically convert light of a specific wavelength.

[0003]

However, since it is a laminated type, there is a problem that the amount of light on the lower layer side is small and the accuracy is lowered.

Therefore, an object of the present invention is to provide a photoelectric conversion module that can perform photoelectric conversion more efficiently.

[0005]

According to the present invention, there are provided light receiving elements having different pn junction depths or band gap energies.
The gist of the invention is a photoelectric conversion module in which a plurality of photoelectric conversion modules are arranged in parallel on the light receiving surface of light having a large number of wavelength components.

[0006]

The light having a large number of wavelength components is received by a plurality of light receiving elements having different pn junction depths or band gap energies. Then, the light of each wavelength component is photoelectrically converted from each light receiving element and extracted as an electric signal.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings. This embodiment is shown in FIGS. 2 shows a plan view of each of the light receiving elements 5, 6, 7, and 8 of the photoelectric conversion module, and FIG. 1 shows a cross section taken along the line AA of FIG.

The light receiving element group 3 of the photoelectric conversion module 2 has four
It consists of one light receiving element 5, 6, 7, 8 and each light receiving element 5,
6, 7, and 8 are arranged side by side on the same plane. That is, the light receiving element group 3 of the photoelectric conversion module 2 has a circular shape, and the four light receiving elements 5, 6, 7, and 8 are divided by the cross-shaped insulating layer 4.

Each of the light receiving elements 5, 6, 7 and 8 is made of silicon and has a pn junction. Then, the light receiving elements 5, 6,
Nos. 7 and 8 have different pn junction depths t. That is,
The junction depths of the light receiving elements 5, 6, 7, and 8 are set to t1, t2, and t, respectively.
Letting t be 3 and t4, t1 <t2 <t3 <t4. A back surface electrode 9 is arranged on the back surface of each of the light receiving elements 5, 6, 7, and 8. In addition, each light receiving element 5, 6,
Electrodes 11 are erected on the side surfaces of 7 and 8 via an insulating layer 10, and are connected to electrodes 12 provided on the surfaces of the light receiving elements 5, 6, 7 and 8 by wires 13. When the light receiving elements 5, 6, 7 and 8 receive light, they are photoelectrically converted and output from the electrodes 9 and 11 through the wire 13.

The light receiving element group 3 is arranged so as to face the end face of the optical fiber 1 as shown in FIG. At this time, the center of the light receiving element group 3 is the light receiving elements 5,
It is arranged so as to be at the center of the optical axis of the medium (optical fiber 1) that gives light to 6, 7, and 8.

Next, the operation of the photoelectric conversion module 2 thus constructed will be described. Light having a large number of wavelength components is sent through the optical fiber 1, and the light is sent from the end face thereof to the light receiving element group 3 of the photoelectric conversion module 2. Then, the light is converted by the light receiving elements 5, 6, 7, and 8 and extracted as an electric signal. At this time, the penetration depth of the light in the light receiving elements 5, 6, 7, and 8 is deeper in the long-wavelength light than in the short-wavelength light.
Therefore, the short wavelength absorption region is concentrated in a shallow region as compared with the long wavelength absorption region, and the long wavelength absorption region is deep as compared with the short wavelength absorption region. Therefore, the light of the short wavelength λ ₁ is photoelectrically converted only by the light receiving element 5 having a shallow junction depth, and the light of the wavelength λ ₂ (> λ ₁ ) is received by the light receiving elements 5 and 6.
And the light of wavelength λ ₃ (> λ ₂ ) is received by the light receiving element 5 and the light receiving element 6.
And the light receiving element 7, the light of wavelength λ ₄ (> λ ₃ ) is received by the light receiving element 5.
Is photoelectrically converted by the light receiving element 6, the light receiving element 7, and the light receiving element 8, and is taken out as an electric signal.

As described above, by using a plurality of light receiving elements 5, 6, 7, and 8 having different pn junction depths t, even if a plurality of wavelengths of light are incident, the wavelength of the incident light can be specified (distinguished). Will be possible.

At this time, the light receiving elements 5, 6, 7, 8
May be a pn-type photodiode, a PIN-type photodiode, or an APD. Further, as the light receiving elements 5, 6, 7, and 8, not only those having different junction depths t but also those having different band gap energies may be used. Since the light receiving elements having different bandgap energies have different absorption sensitivity wavelengths, the light receiving elements that can be photoelectrically converted are different depending on the incident light wavelength. Therefore, it is possible to distinguish the incident light wavelength by the output of the light receiving element.
Further, the plurality of light receiving elements 5, 6, 7 and 8 may be monolithically formed on the same substrate or may be formed on different substrates.

As described above, in this embodiment, the light receiving elements 5, 6 having different pn junction depths or band gap energies are used.
7 and 8 on the light receiving surface of light having many wavelength components,
Since they are arranged in parallel, photoelectric conversion can be performed more efficiently without lowering the amount of light on the lower layer side and lowering the accuracy as in JP-A-2-50487. In addition, JP-A-2-
In the 50487 publication, a plurality of layers having different bandgap energies are laminated in the direction perpendicular to the light receiving surface to selectively photoelectrically convert light of a specific wavelength. Although difficult, in the present embodiment, there is no electrode on the side surface, only the electrode 12 on the front surface of the element and the electrode 9 on the back surface of the element are present. Therefore, the element can be easily formed by using a general semiconductor manufacturing technique. Can be formed.

The present invention is not limited to the above embodiment, and for example, as shown in FIG. 3, the light receiving elements 14, 15, 16, 17 may be linearly arranged in parallel on the light receiving surface. .. Alternatively, it may be carried out as shown in FIG. 4 (plan view of the element). That is, the circular light receiving element 18 and the annular light receiving element 1
9 is separated by the annular insulating layer 20, the light receiving element 19 and the annular light receiving element 21 are separated by the annular insulating layer 22, and the light receiving element 21 and the annular light receiving element 23 are separated by the annular insulating layer 24. .. Then, the light receiving elements 18, 19, 21, 23
The light-receiving areas of the four elements may be set so that the light-receiving amounts of the same are the same. Further, the light receiving elements 18, 19, 21, 23 are designed to have different pn junction depths or band gap energies, so that the wavelength of incident light can be separated. In the figure, 35 is an electrode.

Further, as another embodiment, a plane arrangement of a plurality of light receiving elements is shown in FIG. 5, and FIG. 6 shows B- of FIG.
The B section is shown. An optical waveguide 26 branched into four is formed on the substrate 25, and light receiving elements 27, 28, 29, 30 are formed at the ends of the optical waveguide 26 after the branch. The light receiving elements 27 to 30 have different bandgap energies and can separate the wavelength of incident light. Then, the light from the optical fiber passes through the optical waveguide 26, is branched, and is received by the light receiving elements 27 to 30. Then, the light receiving elements 27 to 30 perform photoelectric conversion for each wavelength component and output as an electric signal. By doing so, it is possible to dispose the photoelectric conversion module capable of detecting each wavelength component on the same substrate. In the figure, 31 is an insulating layer for insulating and separating each element, 32 is an element upper electrode, 33 is an extraction electrode, and 34 is a wire.

[0017]

As described in detail above, according to the present invention,
It exhibits an excellent effect of more efficient photoelectric conversion.

[Brief description of drawings]

1 is a cross-sectional view taken along the line AA of FIG.

FIG. 2 is a plan view of a photoelectric conversion module according to an embodiment.

FIG. 3 is a cross-sectional view of a photoelectric conversion module of another example.

FIG. 4 is a plane surface of another example of a photoelectric conversion module.

FIG. 5 is a plane surface of another example of a photoelectric conversion module.

6 is a sectional view taken along line BB of FIG.

[Explanation of symbols]

 5 Light receiving element 6 Light receiving element 7 Light receiving element 8 Light receiving element

Claims (1)

[Claims] 1. A photoelectric conversion module, wherein a plurality of light receiving elements having different pn junction depths or band gap energies are arranged in parallel on a light receiving surface for light having a large number of wavelength components.