JPH02240527A - Semiconductor photodetecting device - Google Patents

Abstract

PURPOSE:To realize an inexpensive, small-sized photodetecting device with high reliability by connecting the impurity area of a 2nd conduction type of a 1st photodetection part to the impurity area of a 1st conduction type of a 2nd photodetection part and connecting the impurity area of the 2nd conduction type of the 2nd photodetection part to the impurity area of the 1st conduction type of the 1st photodetection part. CONSTITUTION:The semiconductor photodetecting device consists of the 1st photodetection part PD1, the 2nd photodetection part PD2, and a separation area 1. An area 1 is formed as an area of the 2nd conduction type (p type) and the impurity areas 2 and 4 of the photodetection parts PD1 and PD2 which contact the area 1 are formed as areas of the 1st conduction type (n type). Further, n<+> type impurity areas 6 - 8 are formed in the areas 2 and 4 and p type impurity areas 3 and 5 are formed in the impurity areas 2 and 6 in the same shapes to the same density. The p type area 3 of the photodetection part PD1 and the area 7 of the photodetection part PD2 are connected and led out to a terminal (x) and the p type impurity area 5 of the photodetection part PD2 and the impurity area 8 of the photodetection part PD1 are connected and led out to a terminal (y). The difference current between photocurrents IA and IB generated at the photodetection parts PD1 and PD2 appears between the terminals (x) and (y).

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a semiconductor photodetection device that detects light in a specific wavelength band using a semiconductor element, and particularly relates to the structure of the device.

[Conventional technology]

Conventionally, to detect light in a specific wavelength band, an optical filter is placed in front of an optical sensor on a fishing boat, and the H characteristic of this optical filter is determined according to the wavelength band of the light to be detected. As a result, light components in a specific wavelength band, such as red to infrared light and ultraviolet to blue, are detected from the detected light. Alternatively, light in a specific wavelength band has been detected by placing a spectrometer such as a prism in front of the optical sensor.

[Problem to be solved by the invention]

However, detection of light in a specific wavelength band using the conventional configuration described above has a problem in that it is costly because the optical filter and spectrometer are expensive. In addition, these optical filters and spectrometers have a problem in that their transmittance decreases due to moisture absorption, and they deteriorate over time, resulting in poor reliability. Furthermore, the device becomes large in size, and space is required to incorporate this photodetecting device into various devices, making it impossible to miniaturize these devices.

The purpose of the present invention is to solve these problems and provide a compact photodetection device that can be built into various devices without requiring space, and which is also safe and reliable. The purpose is to provide

[Means to solve the problem]

The present invention provides a first light-receiving section in which an impurity region of a second conductivity type is formed in an impurity region of a first conductivity type, and an impurity region of a first conductivity type that is different from the light detection characteristics of the first light-receiving section. A second light receiving section in which a second conductivity type impurity region is formed is electrically insulated and formed on the same substrate, and the second conductivity type impurity region of the first light receiving section is The impurity region of the second conductivity type of the second light receiving section is electrically connected to the impurity region of the first conductivity type of the first light receiving section. It is what was done.

[Effect]

When the same light is irradiated to each of the first and second light receiving sections, different outputs are generated in each of the light receiving sections, and the wiring connected to the impurity region of the second conductivity type of the first light receiving section and the second A difference in the output generated in each light receiving part appears between the wiring connected to the impurity region of the second conductivity type of the light receiving part, and this difference in output is caused by the difference in the output of light in a specific wavelength band of the detected light. It will be proportional to the ingredients.

〔Example〕

FIG. 1 is a sectional view showing one embodiment of the present invention, in which light components in a specific wavelength band of red to infrared light are selected and detected.

The semiconductor photodetector is roughly divided into a first light receiving part PD1 and a second light receiving part PD1.
It is composed of a light receiving section PD2 and a separation region 1, and these are constructed on the same substrate.

Isolation region 1 is made of silicon (Si) and boron (B).
) is diffused to form a p-type. 11111/ of the first light receiving section PCI and the second light receiving section PD2
Impurity regions 2 and 4 in contact with i-region 1 are formed to be n-type, which is the opposite conductivity type to isolation region 1, by selectively diffusing phosphorus (P).

Furthermore, each impurity region 2.4 contains n containing a high concentration of phosphorus.
Type impurity regions 6, 7 and 8 are formed. Also,
By selectively diffusing boron into impurity regions 2 and 6 in the same manufacturing process, p-type impurity regions 3.5 are formed in the same shape and at the same concentration.

Next, by wiring patterning using aluminum (1), the p-type impurity region 3 of the first light receiving portion PDI and the n-type impurity region 7 of the second light receiving portion PD2 are electrically connected. It is pulled out to the terminal
p-type impurity region 5 of D2 and n of the first light receiving portion PCI
The mold impurity region 8 is electrically connected and drawn out to the terminal y.

Therefore, the equivalent circuit of the semiconductor photodetector having the above structure is shown in FIG. That is, the photodiode 9 constituted by the first light receiving section PDI and the second
A photodiode 10 constituted by a light receiving section PD2 of
are connected in antiparallel with each other, and each light receiving section P is connected between each terminal
The structure is such that a difference current between photocurrents 1 and I generated in DI and PD2 appears.

Further, the p-type impurity region 3 and the n-type impurity region 2 form a pn junction of the first light receiving portion PDI, and the p-type impurity region 5 and the n-type impurity region 6 form a pn junction of the first light receiving portion PDI. A pn junction of PD2 is formed. The photodetection characteristics of each of the light receiving sections PDI and PD2 based on each of these pn junctions are shown in the graph of FIG. Note that the horizontal axis in the figure represents the wavelength of light [nml], and the vertical axis represents the sensitivity. The first light receiving section PDI has a characteristic shown by a characteristic curve 11, and detects a light component including a short wavelength band of ultraviolet light to a long wavelength band of infrared light. The second light receiving section PD2 has a characteristic shown by a characteristic curve 12, and detects light components in a short wavelength band from ultraviolet light to visible light, but does not include a long wavelength band from red to infrared. Furthermore, each of the characteristic curves 11 and 12 has the same characteristics in the short wavelength band;
This is because the impurity regions 3 and 5' of F'D2 are formed in the same way.

In such a configuration, when the semiconductor photodetecting device is irradiated with detected light including red to infrared light, carriers are generated in each n-type impurity region 2.4.

- When fishing on a boat, short wavelength light components do not reach deep positions in the substrate and generate carriers at shallow positions, while long wavelength light components generate carriers at deep positions in the substrate. Further, the depletion layer in the first light receiving part PDI does not appear at a shallow position near the surface, and the depletion layer in the second light receiving part PD2 is n+
It is formed at a shallow position by the type impurity region 6. Also,
The range in which carriers are trapped in the depletion layer (within the diffusion distance of carriers) is such that the first light receiving portion PDI is located at a deep position in the substrate, and the second light receiving portion PD2 is located at a shallow position in the substrate. Therefore, the first light receiving section PDI detects carriers generated by light components in the short wavelength band 7 to the long wavelength band, and the second light receiving section PD2 detects carriers generated by light components in the short wavelength band. do.

Therefore, the light to be detected is converted into a current for each light component, and the light component detected by the first light receiving portion PDI becomes a current flowing from the n-type impurity region 2 to the p-type impurity region 3. The light component detected by the second light receiving portion PD2 becomes a current IB flowing from the n+ type impurity region 6 to the p type impurity region 5.

Current IA generated in each light receiving section PDI, PD2.

! , appears as a difference current between terminals x and y, as can be easily understood from the equivalent circuit diagram in FIG. The value of this difference current is determined to a predetermined value depending on how the impurity region 6 of the second light-receiving portion PD2 is formed.
It corresponds to a light component having a specific wavelength band of infrared light. In other words, electric current! ^ is proportional to the sensitivity of the characteristic curve 11 shown in FIG. 3, and the current IB is proportional to the sensitivity of the characteristic curve 12 shown in FIG. For this reason, terminal x
, y are proportional to the sensitivity of the characteristic curve 13 shown by the thick solid line in the same figure, and are
It becomes possible to detect only light having a light component in the infrared wavelength band.

Therefore, according to the embodiment described above, it is possible to detect light components in the red to infrared region of a specific wavelength band without using conventional expensive and unreliable optical filters and spectrometers. In addition, since this device is constructed entirely of semiconductor elements, it can be extremely miniaturized, unlike conventional optical filters, spectrometers, etc., and can also be integrated into a single chip.

Therefore, it becomes possible to incorporate it into various devices without requiring space, and it becomes possible to expand the uses of devices that use a photodetection function. Moreover, since this device can be realized on the same substrate through a simple manufacturing process, it is possible to easily provide an inexpensive and highly reliable device.

In addition, in the above embodiment, the case where the first conductivity type is n type and the second conductivity type is p type is explained, but there is no need to be limited to this, and the first conductivity type is p type and the second conductivity type is p type. It may be an n-type, and the same effects as in the above embodiments can be achieved.

FIG. 4 is a sectional view showing another embodiment of the present invention, in which light components in a specific wavelength band from ultraviolet light to blue are selected and detected.

The semiconductor photodetector device is composed of a first light receiving section PDI, a second light receiving section PD2, and a separation region 21, which are formed on the same substrate, as in the above embodiment.

The isolation region 21 is made of silicon (Si) and phosphorus (P).
) is diffused to form an n-type. The impurity regions 22 and 24 in contact with the isolation region 21 of the first light receiving portion PCI and the second light receiving portion PD2 are p-type, which is the opposite conductivity type to the isolation region 21, by selectively diffusing boron (B). is formed. Furthermore, each impurity region 22.2
A p+ type impurity region 28.degree. 27 containing boron at a high concentration is formed in the region 4. Further, in the impurity region 22, arsenic (A
n type impurity region 23 containing 0.s). In the impurity region 24, an n-type impurity region 25 containing phosphorus is formed to a depth of about 1.5 μm.

Next, by wiring patterning using aluminum, the n-type impurity region 23 of the first light receiving portion PDI and the p + type impurity region 27 of the second light receiving portion PD2 are electrically connected and a terminal X, and the second light receiving section P
n-type impurities @25 in D2 and p in the first light receiving part PCI
The + type impurity region 28 is electrically connected and drawn out to the terminal y.

The semiconductor photodetector having the above structure has an equivalent circuit of the fifth
Shown as shown. That is, two photodiodes constituted by the first light receiving part PDI and a photodiode 30 constituted by the second light receiving part PD2 are connected in antiparallel, and each light receiving part PDI, P is connected between each terminal x, y.
The configuration is such that a difference current between the photocurrents generated in D2 appears. Note that the polarity to which the six photodiodes are connected differs from the equivalent circuit shown in FIG. 2 of the above-described embodiment.

Further, the n-type impurity region 23 and the p-type impurity region 22 form a pn junction of the first light receiving portion PDI, and the n-type impurity region 25 and the p-type impurity region 24 form a pn junction of the first light receiving portion PDI. P
A pn junction of D2 is formed. The photodetection characteristics of each of the light receiving sections PD1°PD2 based on each of these pn junctions are shown in the graph of FIG.

Note that the horizontal axis in the figure represents the wavelength of light [nml], and the vertical axis represents the sensitivity. The first light receiving section PDI has a characteristic shown by a characteristic curve 31, and detects a light component including a short wavelength band of ultraviolet light to a long wavelength band of infrared light. The second light receiving section PD2 has a characteristic shown by a characteristic curve 32, and detects light components in a long wavelength band of visible light to infrared light, but does not include a short wavelength band of ultraviolet light to blue.

In such a configuration, when the semiconductor photodetector is irradiated with light to be detected including ultraviolet light to blue, carriers are generated in each of the p-type impurity regions 22 and 24. In addition, the depletion layer in the shallow (formed) first light receiving part PDI is formed near the surface, and the depletion layer in the deeply formed second light receiving part PD2 does not appear at a shallow position. The first light receiving part PDI has a range from a shallow position to a deep position, and the second light receiving part PD2 has a deep position.For this reason, the first light receiving part PDI has a range from a short wavelength band to a long wavelength band. The second light receiving unit PD2 detects the carriers generated by the optical components in the long wavelength band.Therefore, the detected light is converted into a current for each optical component. and the first light receiving part PC
The light component detected by I becomes a current IA flowing from the n-type impurity region 23 to the p-type impurity region 22.

The light component detected by the second light receiving portion PD2 becomes a current In flowing from the n-type impurity region 25 to the p-type impurity region 24, and has a direction opposite to that of the above-described embodiment.

Current IA generated in each light receiving section PDI, PD2.

IB appears as a difference current between these terminals x and y. The value of this difference current is determined to a predetermined value depending on the difference in the depth at which the impurity regions 23 and 25 of each light receiving part PCI and PD2 are formed, and it is determined to be a predetermined value based on the difference in the depth at which the impurity regions 23 and 25 of each light receiving part PCI and PD2 are formed. It will correspond to the ingredients. That is, the current IB is proportional to the photodetection sensitivity shown in the characteristic curve 31 in FIG. 6, and the current IB is proportional to the photodetection sensitivity shown in the characteristic curve 32 in FIG. Therefore, the terminal x,
These difference currents appearing between y are proportional to the light detection sensitivity shown in the characteristic curve 33 shown by the thick solid line, and it is possible to detect only light having light components in the wavelength range from ultraviolet light to blue. It becomes possible.

Therefore, the above-mentioned embodiment also provides the same effects as the above-described embodiment.

In addition, in the above embodiment, the case where the first conductivity type is p type and the second conductivity type is n type is explained, but there is no need to be limited to this, and the first conductivity type is n type and the second conductivity type is n type. It may be p-type, and the same effects as in the above embodiments can be achieved.

In addition, in each of the two embodiments described above, each light receiving section PD1, PD
Although the description has been made on the case where PDI and PD2 are formed on the same substrate, it is also possible to form each photodetector PDI and PD2 on separate substrates and provide an external circuit to calculate the difference current between the photocurrents generated in each photodetector. I can think about it.

However, the photodetecting device having such a configuration has the following problems, and the present device described above is considered to be more effective. In other words, if each light receiving part is formed separately on each substrate,
First, an external circuit for calculating a difference current between photocurrents generated when the light to be detected is irradiated is required, which increases the size of the device. Second, since an input signal line, an output signal line, and a ground line are required for each light receiving section, each light receiving section PCI, P
The number of wires connecting D2 and the external circuit increases. As a result, the reliability of a photodetecting device in which a light receiving section is provided for each substrate decreases, and furthermore, the manufacturing cost cannot be reduced. However, as described above, this does not occur in the present apparatus according to each of the above embodiments.

In addition, in each of the two embodiments described above, electrical insulation between these regions is achieved by diffusing impurities into the isolation regions.
111♀, however, the isolation region may be made of an electrical insulator made of a dielectric material, and the same effects as in each of the above embodiments can be obtained.

〔Effect of the invention〕

As explained above, in the present invention, the first light receiving section and the second light receiving section are electrically insulated and formed on the same substrate, and the pn junctions of each light receiving section are connected in antiparallel. When the same light is irradiated to the light receiving section, different outputs are generated at each light receiving section, and a difference in the output generated at each light receiving section appears between the wires at each joint, and this difference in output is the difference between the detected light It becomes proportional to the light component in a specific wavelength band.

Therefore, there is no need for conventional expensive and unreliable optical filters and spectrometers, and there is an effect that light of a specific wavelength can be detected using an inexpensive and reliable device.

Furthermore, since the device is entirely composed of semiconductor elements,
The device also has the advantage of being extremely compact and can be easily incorporated into various devices.

[Brief explanation of drawings]

FIG. 1 is a sectional view showing an embodiment of the device according to the invention;
¥42 is an isometric circuit diagram of the device shown in FIG. 1, FIG. 3 is a graph showing the photodetection characteristics of the device shown in FIG. 1, and FIG. 4 is another example of the device according to the present invention. A sectional view showing an example,
FIG. 5 is an equivalent circuit diagram of the device shown in FIG. 4, and the sixth factor is a graph showing the photodetection characteristics of the device shown in FIG. 4. 1... Isolation region (p type), 2.4... First conductive region (
n-type) impurity region, 3, 5... second conductivity type (p-type)
impurity regions, 6.7, 8...high concentration impurity regions of the first conductivity type. Patent applicant Hamamatsu Photonics Co., Ltd. Representative Patent Attorney
Yoshikima Shio for Hase
IfJ Tatsumi - Mei Ibara flJ's Haga 1 Figure 1, one line of 'l! 1st time 21 72 Figure - The light night work of the sales group ii Miman, the first page of the day number 1 Figure 7 Banquet method row O Revalue circuit Figure 5 The practice of dipping! ``'' no Mitsuha Tosae Shusuke

Claims (1)

[Claims] A first light-receiving section in which an impurity region of a second conductivity type is formed in an impurity region of a first conductivity type; A second light receiving section in which a conductive type impurity region is formed is electrically insulated and formed on the same substrate, and the second conductive type impurity region of the first light receiving section is formed in the second light receiving section. The impurity region of the second conductivity type of the second light receiving section is electrically connected to the impurity region of the first conductivity type of the first light receiving section. A semiconductor photodetection device characterized by: