JPH079996B2 - Semiconductor light receiving device - Google Patents

Description

Description: TECHNICAL FIELD The present invention receives a multiplexed light in which a plurality of lights having mutually different wavelengths are multiplexed, and selects a desired light reception output of the multiplexed light. The present invention relates to a semiconductor light receiving device that can be selectively output.

2. Description of the Related Art Conventionally, it is possible to receive a multiplexed light in which a plurality of lights having different wavelengths are multiplexed and selectively output a desired light receiving output of the multiplexed light. There is no proposal for a semiconductor light receiving device.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention For this reason, conventionally, a multiplexed light in which a plurality of lights having different wavelengths are multiplexed is received, and a desired one of the multiplexed lights is received.
To selectively output the received light of one light, a plurality of semiconductor light receiving elements corresponding to a plurality of lights forming a multiplexed light and a plurality of semiconductor light receiving elements are received, and the plurality of lights constituting the light are separated respectively. And a plurality of optical demultiplexers for respectively injecting the plurality of demultiplexed lights into a plurality of semiconductor light receiving elements are prepared in advance, and with an output obtained from one of the plurality of semiconductor light receiving elements, It was used as the received light output of one desired light in the multiplex light.

Therefore, in the case of receiving a multiplexed light in which a plurality of lights having mutually different wavelengths are multiplexed and selectively outputting the light receiving output of a desired one of the multiplexed lights, the device for that purpose is large in size as a whole. It had the drawback of being expensive.

By the means for solving the problem, the present invention, without the drawbacks mentioned above, receives a multiplexed light multiplexing a plurality of lights having mutually different wavelengths,
An object of the present invention is to propose a novel semiconductor light receiving device capable of selectively outputting the light receiving output of a desired one of the multiplexed lights.

A semiconductor light receiving device according to the present invention includes a first semiconductor layer having a first conductivity type, first and second semiconductor layers having different energy band gaps, and an impurity concentration sufficiently lower than that of the first semiconductor layer. A semiconductor active layer having a structure in which a large number of second semiconductor thin films are alternately laminated to form a multiple quantum well, and a second conductivity type opposite to the first conductivity type. A semiconductor laminated body having a structure in which a second semiconductor layer is laminated in that order, and first and second electrodes attached to the first and second semiconductor layers of the semiconductor laminated body, respectively. And a first or second semiconductor light receiving element having a structure in which the first and second semiconductor light receiving elements are arranged side by side or stacked, and at least the first or second semiconductor laminated body of the first and second semiconductor laminated bodies is provided. The electrodes are separated from each other,
Alternatively, the second electrode of the first semiconductor laminate and the second electrode
Or the first electrode of the semiconductor laminated body is separated from each other, or the first electrode of the first semiconductor laminated body and the second electrode of the second semiconductor laminated body are separated from each other.

In the case of the semiconductor light receiving device according to the present invention having such a configuration, in each of the first and second semiconductor light receiving elements, the semiconductor active layer does not constitute a multiple quantum well, If the semiconductor layer is replaced with a semiconductor layer having an impurity concentration sufficiently lower than that of the second semiconductor layer, it has the same configuration as that of the conventional semiconductor light receiving device. , By receiving the light, the light reception output of the light is output via the first and second electrodes.

However, in the case of the semiconductor light receiving device according to the present invention, in each of the first and second semiconductor light receiving elements,
Since the semiconductor active layer constitutes a multiple quantum well, if an electric field corresponding to the voltage is applied by applying a voltage between the first and second electrodes, a wavelength corresponding to the electric field strength is generated. By receiving light having a longer wavelength, most or most of the light is absorbed, but even if light having a wavelength shorter than the wavelength according to the electric field strength described above is received, Little or little if absorbed.

Therefore, even if each of the first and second semiconductor light receiving elements receives light having a wavelength shorter than the wavelength corresponding to the voltage applied between the first and second electrodes thereof, it receives the light. Although it does not output an output, by receiving light having a long wavelength, the light reception output of the light is output via the first and second electrodes.

Therefore, according to the semiconductor light receiving device of the present invention, a plurality of wavelengths having different wavelengths are provided from the side opposite to the second semiconductor light receiving element side of the first semiconductor light receiving element toward the second semiconductor light receiving element side. Light of the first and second semiconductor light receiving elements is made to enter.
And separately applying a voltage between the second electrodes,
Then, if those voltages are appropriately selected, a desired light receiving output of a plurality of lights forming the multiplex light is received from the second semiconductor light receiving element via the first and second electrodes. Can be output.

Therefore, according to the semiconductor light receiving device of the present invention, only the semiconductor light receiving device of the present invention is used, and accordingly, the semiconductor light receiving element, the optical demultiplexer, and the plurality of light beams forming the multiplex light are provided. Receiving multiplexed light in which a plurality of lights having mutually different wavelengths are multiplexed without requiring an optical coupling path, and selectively outputting a received light output of a desired one of the multiplexed lights It has the excellent feature that

First Embodiment Next, a first embodiment of the semiconductor light receiving device according to the present invention will be described with reference to FIG.

The semiconductor light receiving device according to the present invention shown in FIG. 1 has a configuration described below.

That is, it has a configuration in which the first and second semiconductor light receiving elements U1 and U2 are arranged side by side.

Each of the semiconductor light receiving elements U1 and U2 includes, for example, a first semiconductor layer 11 made of InP and having an n-type, and a semiconductor active layer.
13 and a second semiconductor layer 12 made of, for example, the same InP as the first semiconductor layer 11 and having a p-type opposite to that of the first semiconductor layer 11.
And the semiconductor active layer 13 of the semiconductor layers 11 and 12 of the semiconductor laminate 10
It has a structure having first and second electrodes 21 and 22 which are respectively ohmiced on the surface opposite to the side.

In this case, the semiconductor active layer 13 is, for example, an InPGaAs-based semiconductor layer 33a having an impurity concentration sufficiently lower than those of the first and second semiconductor layers 11 and 12, and an InAlAs semiconductor layer 33a having an energy band gap different from that of the semiconductor layer 33a. And a plurality of semiconductor layers 33b which are of a system and have a sufficiently lower impurity concentration than the first and second semiconductor layers 11 and 12 are alternately laminated to form a multiple quantum well. is doing.

Incidentally, the semiconductor light receiving elements U1 and U2 having the above-mentioned configuration
Has the following configuration in practice.

That is, the first semiconductor layer 11 of the semiconductor light receiving elements U1 and U2
On the semiconductor layer 41 to be the semiconductor active layer 43 to be the semiconductor active layer 13 of the semiconductor light receiving elements U1 and U2, and the semiconductor light receiving element U1.
And the semiconductor layer 42 that will become the second semiconductor layer 12 of U2 are stacked in that order, and the semiconductor stacked body is divided into two by the irradiation of protons from above in the semiconductor stacked body.
So that the insulating layer 44 is formed to a depth reaching the semiconductor layer 41, so that the regions at both positions of the semiconductor layer 42 sandwiching the insulating layer 44 are respectively separated by the second semiconductors of the semiconductor light receiving elements U1 and U2. As the layer 12, the regions of the semiconductor active layer 43 at both positions sandwiching the insulating layer 44 are respectively defined as the semiconductor active layer 13, and further, the regions under the semiconductor active layer 13 of the semiconductor layers U1 and U2 of the semiconductor layer 41 are respectively formed. First semiconductor layer 11 of semiconductor layers U1 and U2
It has the configuration.

In addition, since the above-mentioned semiconductor layer 41 is not divided into two, an electrode serving as the electrode 21 of the first and second semiconductor light receiving elements U1 and U2 is formed on the surface of the semiconductor layer 41 opposite to the semiconductor layer 42 side. 45 is formed, and regions of the electrode 45 below the semiconductor layer 11 of the first and second semiconductor light receiving elements U1 and U2 are used as the electrodes 21 of the first and second semiconductor light receiving elements U1 and U2.

The above is the configuration of the first embodiment of the semiconductor light receiving device according to the present invention.

According to the semiconductor light receiving device of the present invention having such a configuration, in each of the semiconductor light receiving elements U1 and U2, instead of the semiconductor active layer 13 constituting a multiple quantum well, the first and second semiconductor light receiving elements are formed. If replaced with a semiconductor layer having an impurity concentration sufficiently lower than those of the semiconductor layers 11 and 12,
Since it has the same structure as a conventional semiconductor light receiving element,
As in the case of the conventional semiconductor light receiving element, it is obvious that by receiving light, the light reception output of the light is output via the first and second electrodes 21 and 22.

However, each of the semiconductor light receiving elements U1 and U2 is
The semiconductor active layer 13 has a structure forming a multiple quantum well.

Therefore, in each of the semiconductor light receiving elements U1 and U2, the semiconductor active layer 13 has the first and second electrodes 21 and
If a voltage is applied between the electrodes, an electric field corresponding to the voltage is applied, and light having a wavelength longer than the wavelength corresponding to the electric field strength is received to absorb all or most of the light. However, even if the light having a wavelength shorter than the wavelength corresponding to the electric field intensity is received, the light is hardly absorbed or slightly absorbed.

Therefore, each of the first and second semiconductor light receiving elements U1 and U2 receives light having a wavelength shorter than the wavelength corresponding to the voltage applied between the first and second electrodes 21 and 22 thereof. Does not output the light reception output of the light, but by receiving the light having a wavelength longer than the wavelength corresponding to the voltage applied between the first and second electrodes 21 and 22, the light reception output of the light is Output is made via the first and second electrodes 21 and 22.

Therefore, a plurality of light beams having different wavelengths, for example, four light beams L ₁
Light L that multiplexes L ₄ to L ₄ is made to enter from the side opposite to the second semiconductor light receiving element U2 side of the first semiconductor light receiving element U1 toward the second semiconductor light receiving element U2 side, Also,
First and second electrodes of the first and second semiconductor layers U1 and U2
If voltages are separately applied between 21 and 22, and the voltages are appropriately selected, the light L ₁ , L ₂ ,
The wavelengths of L ₃ and L ₄ are λ ₁ , λ ₂ , λ ₃ and λ, respectively.
₄ , and if the wavelengths λ ₁ , λ ₂ , λ ₃ , and λ ₄ have a relation of λ ₁ <λ ₂ <λ ₃ <λ ₄ , for example, the light L ₁ in the multiplexed light L And L ₂ are semiconductor photodetectors
Mostly or mostly absorbed by U1, semiconductor photodetector U1
Is hardly transmitted, or is slightly transmitted even if it is transmitted.

However, the remaining lights L ₃ and L ₄ in the multiplexed light L are hardly absorbed by the semiconductor light receiving element U1, or only slightly absorbed if absorbed, and pass through the semiconductor light receiving element U1.
It is incident on the semiconductor light receiving element U2 through the insulating layer 44.

In addition, the light L ₃ and the light incident on the semiconductor light receiving element U 2 are
L ₄ light L ₄ in also not little absorbed as being absorbed or is hardly absorbed by the semiconductor light receiving device U2, is emitted to the outside the semiconductor light-receiving element U2.

However, most or most of the light L3 in the light L3 and the light L4 is effectively absorbed by the semiconductor light receiving element U2,
As a result, the received light output of the light L _{3 is} the first light output of the semiconductor light receiving element U 2.
And are output via the second electrodes 21 and 22.

In the above description, only the received light output of the light L ₃ in the multiplex light L described above is output.
By changing the voltage applied between the first and second electrodes 21 and 22 of the second semiconductor layers U1 and U2 from the above-mentioned case, the light-receiving output of any light in the above-mentioned multiplex light L can be obtained. It will be clear that output can be provided via the first and second electrodes 21 and 22.

Second Embodiment Next, a second embodiment of the semiconductor light receiving device according to the present invention will be described with reference to FIG.

In FIG. 2, parts corresponding to those in FIG. 1 are designated by the same reference numerals and will be described in detail.

The second embodiment of the semiconductor light receiving device according to the present invention shown in FIG. 2 is the same as the first and second semiconductor light receiving devices in the configuration of the first embodiment of the semiconductor light receiving device according to the present invention described above with reference to FIG. The elements U1 and U2 of the first embodiment of the semiconductor light receiving device according to the present invention described above with reference to FIG. 1 except that the elements U1 and U2 are arranged side by side instead of being arranged side by side. It has the same configuration as the embodiment.

However, in this case, the first semiconductor light receiving element U1 has a configuration in which it is stacked on the second semiconductor light receiving element U2, and the first and second electrodes 21 and 22 of the first semiconductor light receiving element U1. Light-transmitting windows 51 and 52 are provided in the second semiconductor layer U1, and similar windows 51 are also provided in the first electrodes 21 and 22 of the second semiconductor layer U1.

In the semiconductor light receiving device having the above-described structure according to the present invention, the first and second semiconductor light receiving elements U1 and U2 are separately obtained, and the first semiconductor light receiving element U1 is replaced by the second semiconductor light receiving element U2. The first electrode of the first semiconductor light receiving element U1
It is obtained by fusing 21 and the second electrode 22 of the second semiconductor light receiving element U2 and stacking them.

The above is the configuration of the second embodiment of the semiconductor light receiving device according to the present invention.

According to the second embodiment of the semiconductor light receiving device of the present invention having such a configuration, except for the matters described above,
Since it has the same configuration as that of the first embodiment of the semiconductor light receiving device according to the present invention described above with reference to FIG. 1, a detailed description thereof will be omitted. For example, the multiplex light L similar to that described above in the first embodiment is omitted.
From the side opposite to the semiconductor light receiving element U2 side of the semiconductor light receiving element U1 toward the semiconductor light receiving element U2 side.
Of light is applied through the window 51 of the first and second semiconductor layers U1 and U2, and a voltage is separately applied between the first and second electrodes 21 and 22 of the first and second semiconductor layers U1 and U2. If properly selected, for example, the light L ₁ in the multiplexed light L is
Most or most of the light is absorbed by the semiconductor light receiving element U1, and it does not pass through the semiconductor light receiving element U1 or only slightly if it passes through.

However, the remaining lights L ₂ , L ₃ and L ₄ in the multiplexed light L are
The semiconductor layer U1 hardly absorbs it or slightly absorbs it, and therefore passes through the semiconductor photodetector U1 and then the window 52 of the semiconductor photodetector U1 and the semiconductor photodetector U1.
The light enters the semiconductor light receiving element U2 through the window 51 of U2.

Most of the light L _3, L ₄ and light L ₃ and L _{4 in the} light L ₂ , L ₃ and L ₄ are not absorbed by the semiconductor light receiving element U2 or slightly absorbed even if they are absorbed by the semiconductor light receiving element U2. Then, the light L ₂ is emitted to the outside through the window 52. However, the light L ₂ is almost absorbed by the semiconductor light receiving element U 1, and as a result, the light receiving output of one light L ₂ in the light L is changed to the semiconductor light receiving element. It is output via the first and second electrodes 21 and 22 of U2.

In the first embodiment shown in FIG. 1, the first and second
The first electrodes 21 of the semiconductor stacks U1 and U2 are connected to each other, but the second electrodes of the first and second semiconductor stacks U1 and U2 are connected to each other.
Although the case where the electrodes 22 are separated from each other is shown, instead of this, the second electrodes 22 of the first and second semiconductor stacked bodies U1 and U2 are connected to each other. It is also possible to have a configuration in which the second electrodes 21 of the first and second semiconductor stacked bodies U1 and U2 are separated from each other,
In the second embodiment shown in FIG. 2, the first and second
Semiconductor stacks U1 and U2 of the first semiconductor stack U1
The electrode 21 and the second electrode 21 of the second semiconductor laminate U2 are stacked so as to be connected to each other,
The case where the second electrode 22 of the first semiconductor stacked body U1 and the first electrode 21 of the second semiconductor stacked body are separated from each other is shown, but instead of that, the first and second The two semiconductor stacked bodies U1 and U2 are stacked such that the first electrode 21 of the first semiconductor stacked body U1 and the first electrode of the second semiconductor stacked body U2 are connected to each other. The second electrode 22 of the first and second semiconductor stacked bodies U1 is separated from each other, and the first and second semiconductor stacked bodies U1 and U2 are the first and second semiconductor stacked bodies. The second electrodes 22 of the body are stacked so as to be connected to each other so that the first electrodes 21 of the first and second semiconductor stacked bodies U1 and U2 are separated from each other. , The first and second semiconductor laminates U1 and U2 are
Second electrode 22 of the semiconductor laminate U1 and the second semiconductor laminate
By stacking so as to connect with the first electrode 21 of U2, the first electrode 21 of the first semiconductor laminate U1 and the first electrode 21 of the second semiconductor laminate U2 are separated from each other. Obviously, it is also possible to have various configurations, and various modifications and changes can be made without departing from the spirit of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing a first embodiment of a semiconductor light receiving device according to the present invention. FIG. 2 is a schematic sectional view showing a second embodiment of the semiconductor light receiving device according to the present invention. U1, U2 …… Semiconductor light receiving element 10 …… Semiconductor laminate 11, 12 …… Semiconductor layer 13 …… Semiconductor active layer 21, 22 …… Electrodes 33a, 33b …… Semiconductor layers 41, 42 …… Semiconductor layer 43 …… Semiconductor active layer 44 ... Insulating layers 51, 52 ... Window

Claims (1)

[Claims] 1. A first semiconductor layer having a first conductivity type,
The first and second energy bands have different energy band gaps.
A semiconductor active layer having a structure in which a large number of first and second semiconductor thin films having an impurity concentration sufficiently lower than that of the semiconductor layer are alternately stacked, and which constitutes a multiple quantum well; A second having a second conductivity type opposite to the first conductivity type
A semiconductor laminated body having a structure in which the semiconductor layers of the above are laminated in that order, and the first and second semiconductor laminated bodies described above.
The first and second semiconductor light receiving elements having the first and second electrodes respectively attached to the semiconductor layer, are arranged side by side or stacked, and at least the above The first or second electrode of the first and second semiconductor laminated bodies are separated from each other, or the second electrode of the first semiconductor laminated body and the first electrode of the second semiconductor laminated body are separated from each other.
Or the first electrode of the first semiconductor laminated body and the second electrode of the second semiconductor laminated body are separated from each other.