JPS61140827A - Semiconductor photodetecting device - Google Patents

Abstract

PURPOSE:To eliminate a dead zone while securing the separation of adjacent photoelectric conversion parts by projecting and recessing plane shapes of photoelectric conversion parts so that recessed parts and projected parts of adjacent photoelectric conversion parts are interlaced with each other. CONSTITUTION:Plural photoelectric conversion parts 4 (4-1-4-n) are provided successively on a substrate 1 and connected to a scanning circuit 2 through a switch part 3 to constitute a semiconductor photodetecting device. The plane outer peripheral shapes of each photoelectric conversion part 4 is projected and recessed. Then, adjacent photoelectric conversion parts 4 are so arranged that projected parts and recessed parts are interlaced with each other across a separation area having a protection film. Consequently, straight lines S1 and S2 perpendicular to the array direction of the photoelectric conversion parts 4 face at least one photoelectric conversion part without fail and no dead zone is formed even when the separation area is secured sufficiently.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a semiconductor photodetection device that is used for spectroscopic spectral measurements that require high resolution.

(Prior Art) A photodiode array type semiconductor photodetection device having a self-scanning function has been developed.

It has sensitivity ranging from ultraviolet to infrared rays, and has been able to obtain images of considerable resolution.

Such a semiconductor photodetector has the excellent feature that it is not necessary to use a conventional wavelength scanning mechanism when dispersing light of short duration, and that it can measure multiple wavelengths in the open state.

Therefore, by processing these signals with a computer, it is possible to measure correlations between wavelengths and changes in intensity, etc., and it has been widely applied.

FIG. 4 is a plan view of a conventional self-scanning semiconductor photodetector, and FIG. 5 is a cross-sectional view of a photoelectric conversion section of the semiconductor photodetector.

This self-scanning semiconductor photodetector device includes a photoelectric conversion section 4 that also serves as a photogenerated charge storage section, a signal reading switch section 3, and a scanning circuit section 2 for addressing the switch, all of which are provided on the same substrate. It is configured.

In the figure, 5, 6.7 are clock input terminals, and 8 is a signal output terminal.

The photoelectric conversion unit 4 is normally floating, and the switch/
The potential is fixed when turned on, and the potential changes as charges are accumulated according to the light intensity.

The clock input terminals 5, 6.7 of the scanning circuit section 2 are supplied with pulse voltages for sequentially addressing the switch section 3 from an external clock pulse generating means.

When an address signal is applied to the switch section 3, a current flows through the external circuit until the potential of the signal line and the potential of the photoelectric conversion section 4 become equal.

This current is proportional to the light intensity and charge storage time, and the light intensity distribution in each photoelectric conversion unit 4 is extracted in time series.

In such semiconductor photodetecting devices, crosstalk between photoelectric conversion units and generation of dead zones always pose problems. As shown in FIG. 5, in order to eliminate crosstalk between adjacent elements, a distance sufficient to form a separation region is required between the photoelectric conversion units 4.

The surface of the photoelectric conversion section and the surface of the isolation region are covered with a silicon oxide film 9, for example.

However, especially in the detection of high-energy sources such as strong ultraviolet light or electron beams, the silicon oxide film protecting this isolation region can be degraded, contributing to impaired decomposition.

In the conventional structure as shown in FIG. 5, in order to improve signal purity, it is necessary to widen the separation region (region between the photoelectric conversion sections 4) that separates the photoelectric conversion sections.

However, if this area is widened, this area becomes a so-called dead zone, which will lead to a decrease in the signal amount.Also, if the pinch of the photoelectric conversion section is determined, widening the gap between the photoelectric conversion sections That is, the charge storage section becomes less troublesome, and photogenerated charges are reduced.Furthermore, the maximum amount of accumulated charge is also reduced, and the linear region of the illuminance-output characteristic on the high output side becomes narrower.

Furthermore, as mentioned above, when detecting ultraviolet light, particles, etc., it is necessary to protect the oxide film between the photodiodes.
In this case as well, there is a dead zone between the photodiodes.

However, this dead zone may cause a serious problem during measurement.

For example, in the case of a very narrow emission line spectrum, such as in plasma emission spectrometry, the spectrum that is desired to be completely measured may fall within the dead zone, and no signal may be obtained.

In order to solve the problem of such a dead zone, a configuration as shown in FIG. 6 can be considered.

That is, the photoelectric conversion units are arranged in the first row 4a...4a and the second row 4.
b...4b are arranged in two rows, upper and lower, so as to mutually compensate for dead zones.

In the figure, 2a and 2b are scanning circuits, 3a and 3b are switches, 5a to 7a and 5b to 7b are clock input terminals, and 8
a and 8b are signal output terminals.

With this configuration, the dead zone problem can be solved to some extent.

However, for example, if the light beam S from the slit is not at the center of the upper and lower photodiode parts as shown in the figure, or if the light intensity distribution in the slit light beam is different between the upper and lower parts, a difference in output between the upper and lower parts will occur. .

Therefore, although this configuration solves the problem of the dead zone, it does not completely solve the problem of the position and length of the light beam and the non-uniformity of the light beam.

(Object of the Invention) An object of the present invention is to provide a semiconductor photodetection device that can solve the above-mentioned problems of dead zone and separation.

(Structure of the Invention) In order to achieve the above object, a first semiconductor photodetection device according to the present invention includes a plurality of photoelectric conversion sections arranged in the scanning direction via a switching section, and a plurality of photoelectric conversion sections arranged in a scanning direction via a switch section. In a semiconductor photodetection device connected to a circuit, the planar shape of the photoelectric conversion section is provided with unevenness, and the convex portions of the photoelectric conversion sections adjacent to the four parts of one photoelectric conversion section are separated through separation regions having a protective film. Arranged so that it corresponds to
The arrangement is such that any straight line perpendicular to the arrangement direction t of the photoelectric conversion sections lies on one or two of the photoelectric conversion sections.

Further, in the second semiconductor photodetecting device, a plurality of first photoelectric conversion units are arranged in the scanning direction via separation regions, and each is connected to the first scanning circuit via the first switch unit,
A semiconductor photodetector in which a second photoelectric conversion section is arranged parallel to the first photoelectric conversion section via a separation region, and each of the second photoelectric conversion sections is connected to a second scanning circuit via a second switch section. In the device, a first photoelectric conversion section and a second photoelectric conversion section are arranged in a pattern with a planar shape of each of the photoelectric conversion sections interposed therebetween via a separation region having a protective film, and The structure is such that an arbitrary straight line perpendicular to the arrangement direction is located at one or two of the photoelectric conversion sections.

(Example) Hereinafter, the present invention will be described in more detail with reference to the drawings and the like.

1st page! ! FIG. 1 is a plan view showing an embodiment of a semiconductor photodetection device according to the present invention.

On an N-type semiconductor substrate 1, a scanning circuit 2, a switch section 3,
A photoelectric conversion section 4 is formed.

The photoelectric conversion section 4, which is made up of a junction formed between an N-type substrate I and a P-type layer on the front surface, is provided with an image portion projecting to the right and a recess on the left side.

The four parts of one photoelectric conversion part are arranged so that the convex parts of adjacent photoelectric conversion parts are made to correspond to each other via separation regions having a protective film.

In this embodiment, the pitch p of the photoelectric conversion unit 4 is 75 ttm.
, the width d of the photoelectric conversion section 4 is 60 μm, and the length l is 2°5 mm.
It is said that

If the light beam formed by the slit is now incident on the position S1, outputs will appear from the photoelectric conversion units 4-1 and 4-2. When the light beam formed by the slit enters the position S2, an output appears from the photoelectric conversion section 4-2.

As described above, in this embodiment device, any straight line perpendicular to the arrangement direction of the photoelectric conversion units 4 exists on one or two of the photoelectric conversion units, and even when detecting a bright line spectrum, there is no dead zone. Therefore, signal output can always be obtained from one or two photoelectric conversion sections 4.゛Also, in this case, even if there is a difference in the intensity distribution of the spectral luminous flux above and below, it is almost iI! ! 4 No difference.

However, in this embodiment, the peripheral length is longer than the area of the photoelectric conversion unit 4, that is, the photodiode, which may lead to an increase in dark current due to surface leakage current. Note that this problem will be solved by the configuration number described later.

Generally, the dark current of a normal photodiode is given as the sum of the reverse saturation current, the current generated in the depletion layer, and the surface leakage current.The reverse saturation current and the current generated in the depletion layer are determined by the area of the diffusion layer, and the surface leakage current is determined by the diffusion layer. It is proportional to the layer perimeter.

FIG. 2 is a plan view showing an embodiment of a second semiconductor photodetecting device according to the present invention.

A pair of self-scanning semiconductor photodetectors are provided on the same N-type substrate 1.

First photoelectric conversion units 4a...4a and scanning circuit 2a.

The switch unit 3a allows the first self-scanning semiconductor photodetector, the second photoelectric conversion units 4b...4b, and the scanning circuit 2b,
A second self-scanning semiconductor photodetector device is formed by the switch section 3b.

The first and second photoelectric conversion sections 4a and 4b each have an isosceles triangular shape (model) with the switch side as the base.

These are arranged so that they intertwine and intertwine.

Like the device of the previous embodiment, this embodiment also has no dead zone, eliminating the problem of no output depending on the incident position.

Compared to the embodiments described above, this embodiment is characterized in that the outlines of the photoelectric conversion sections 4a, 4b, etc. are simpler and shorter.

Next, examples of separation regions for separating the photoelectric conversion units 4 of each of the above embodiments and their protective films will be described.

In the structure shown in FIG. 3 (A>), a plurality of photoelectric conversion sections 4 are formed on the surface of an N-type substrate 10, and a silicon dioxide film is formed on the surface.

A blocking layer 10 made of a polycrystalline semiconductor layer is formed on the upper surface of the separation region between the photoelectric conversion parts 4 to block incident light.

This blocking layer 10 absorbs high-energy particle beams and prevents them from reaching the separation region, thereby preventing deterioration of the separation region.

Note that an aluminum layer can also be used as the blocking layer.

The structure shown in FIG. 3(B) is a structure for ensuring separation between the photoelectric conversion units 4.

An N-type layer 13 with a thickness of about 5 μm is formed on the P-type substrate 12 by epitaxial growth, and an isolation groove is formed by plasma etching in the part that will become the isolation region of the photoelectric conversion section 4. Polycrystalline silicon 11 is formed in this groove by CVD. Embed.

After that, a P-type f4 region forming the photoelectric conversion section 4 is provided.

As a result, crosstalk can be completely prevented by diffusing photocharges generated between adjacent photoelectric conversion parts and deep within the substrate.

Various modifications can be made to the embodiments described in detail above within the scope of the present invention.

Although the planar shape of the photoelectric conversion section has been shown to have angular irregularities or a triangular shape, various modifications can be made to these shapes. In short, for the first embodiment, any linear shape perpendicular to the arrangement direction of the photoelectric conversion sections or an uneven shape such as that on the second photoelectric conversion section may be used. It may be.

This also applies to the device of the second embodiment. Further, the configuration of the isolation region and the protective film described in FIG. 3 can be applied to the first and second semiconductor photodetecting devices selectively or simultaneously.

Further, in the embodiments, an N-type epitaxial layer is applied to an N-type silicon substrate or a P-type silicon substrate, but the present invention can also be applied to a substrate using a substrate of the opposite conductivity type.

Further, the semiconductor photodetector according to the present invention can be widely used in fields requiring high resolution, even if it is not spectroscopic analysis.

(Effects of the Invention) As explained above in detail, each semiconductor photodetector according to the present invention completely eliminates the dead zone by intricately configuring the photoelectric conversion section, so it is possible to capture even extremely thin linear spectra.

Furthermore, since each photoelectric conversion section can be formed within the same width in the direction perpendicular to the scanning direction, it is possible to reduce changes in output due to differences in the intensity of incident light in the width direction or positional deviations in the width direction.

Further, isolation can be ensured by burying a polycrystalline semiconductor or an insulator in the isolation region.

Thereby, a photoelectric conversion section having a relatively complicated external shape can be easily realized.

In this way, according to the present invention, a high resolution semiconductor photodetection device free of dead zones and crosstalk can be obtained, making it possible to perform various measurements that were previously impossible.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a plan view showing an embodiment of a first semiconductor photodetecting device according to the present invention. FIG. 2 is a plan view showing an embodiment of a second semiconductor photodetecting device according to the present invention. FIG. 3 is a sectional view showing an embodiment of the separation region and the protective film. FIG. 4 is a plan view showing an example of the configuration of a conventional semiconductor photodetecting device. FIG. 5 is a sectional view of the photoelectric conversion section of the conventional semiconductor photodetecting device. FIG. 6 is a plan view of a semiconductor photodetection device considered to eliminate the dead zone. 1...N-type silicon substrate 2.2a, 2b...scanning circuit (shift register)3.
3a, 3b...Switches 4.4a, 4b...Photoelectric conversion section (P-type layer photodiode) 5-7.5a-7a, 5b-7b...Clock input terminals 8.8a, 8b... Signal output terminal 9...Silicon oxide film 10...Polycrystalline silicon or aluminum 11...
・Polycrystalline silicon or insulator 12...P-type substrate 13...N-type epitaxial layer Patent applicant Hamamatsu Photonics Co., Ltd. Representative Patent attorney Cause

Claims (4)

[Claims] (1) In a semiconductor photodetector device in which a plurality of photoelectric conversion sections are arranged in the scanning direction via separation regions, and each of them is connected to a scanning circuit via a switch section, the outer shape of the photoelectric conversion section is provided with unevenness, The concave portion of one photoelectric conversion portion and the convex portion of the adjacent photoelectric conversion portion are arranged so as to correspond to each other via a separation region having a protective film, and any straight line perpendicular to the arrangement direction of the photoelectric conversion portion is 1 or 2. A semiconductor photodetection device characterized in that the semiconductor photodetection device is configured to be located on the photoelectric conversion section of No. 2. (2) The semiconductor photodetecting device according to claim 1, wherein the protective film of the separation region is made of aluminum or a polycrystalline semiconductor. (3) The semiconductor photodetecting device according to claim 1, wherein the isolation region is embedded with a polycrystalline semiconductor or an insulating material of the same conductivity type as the isolation region. (4) A plurality of first photoelectric conversion units are arranged in the scanning direction via separation regions, each is connected to the first scanning circuit via the first switch unit, and the second photoelectric conversion unit In the semiconductor photodetector device, each of the photoelectric conversion units is arranged in parallel along the first photoelectric conversion unit via a separation region, and each of the photoelectric conversion units is connected to a second scanning circuit via a second switch unit. The planar shape of the section is wedge-shaped, and the first photoelectric conversion section and the second photoelectric conversion section are intertwinedly arranged through a separation region having a protective film, and any straight line perpendicular to the arrangement direction of the photoelectric conversion section A semiconductor photodetecting device characterized in that the semiconductor photodetecting device is configured such that one or two of the photoelectric conversion sections are provided.