JPH03262168A - Photodetector - Google Patents

Abstract

PURPOSE:To decrease a series resistance of a photodetector so as to improve it in responsivity by a method wherein a contact section is provided along the long side of a P-type diffusion layer which serves as surface electrodes of the photodetectors provided to the inner side of the surface of an N-type semiconductor substrate, and a diffusion layer is provided along the inner circumference of peripheral photodetectors which surround the photodetectors so as to connect the P-type diffusion layer and the N-type substrate together. CONSTITUTION:Long contact sections 20, 20, 20, and 20 are provided onto the surface of inner photodetectors elements 2, 3, 4, and 5 along the long sides of P<+>-type diffusion layers 13, 14, 15, and 16 and connected to Al electrode wirings 7, 8, 9, and 10 penetrating through an insulating film 12. An N<+>-type diffusion region 19 is formed along the inner circumference of a P-type diffusion layer 17 on the surface of peripheral photodetectors 6 which surround the inner photodetectors 2, 3, 4, and 5. The N<+>-type diffusion region 19 enables the P<+>-type diffusion layer 17 to be short-circuited to the N layer of the semiconductor substrate 1 along the overall inner circumference of the peripheral photodetectors 6. A contact 19-1 is provided to a part of the N<+>-type diffusion region 19 and wired to a cathode electrode 11 penetrating through the insulating film 12.

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention provides high-speed response of a light-receiving element that is used for detecting the amount of received light and is composed of a plurality of rectangular light-receiving elements and peripheral light-receiving elements surrounding them. It is about the structure that changes.

(Prior Art) FIG. 2(a) is a plan view of an example of a conventional light receiving element in which a plurality of rectangular light receiving elements and surrounding peripheral light receiving elements are formed on a single semiconductor substrate, and FIG. -B' sectional view is FIG. 2(b). A photodiode is generally used as a light receiving element.

As shown in these drawings, for example, a P-type diffusion layer 17 is provided at the periphery of the surface of the Nfi semiconductor substrate 1, and a P-type diffusion layer 17 is provided inside it at a certain distance.
+8.14 and 15.16 are formed. The light receiving element 2 is formed by the PN junction between the P-type diffusion layer 13 and the semiconductor substrate I.
are formed, and P-type diffusion layers 14, 15 .
16 and the semiconductor substrate 1 form a light receiving element 8, 4.5. In addition, the peripheral P-type diffusion layer 17 and the semiconductor substrate l
A peripheral light-receiving element 6 is thus formed. A N mineral dispersion layer 18 is provided around the outer periphery of this chip to serve as a channel stopper.

The surface of the light-receiving element is covered with an insulating film 12, holes are made in necessary parts, and wiring is formed by vapor depositing At, for example, and electrode wirings 7, 8 are formed.
,9,10. etc. will be provided. The electrode wiring 7 is connected to the contact portion 20 of the P-type diffusion layer I3, and the electrode wiring 8, 9
．． 10 are contact portions 20, 20 of P+ type diffusion layers 14, 15, and 16, respectively.

20VC is connected. An N-type diffusion region is formed on a part of the surface of the semiconductor substrate I to improve ohmic contact]9
, which is connected to the cathode electrode 11 made of AA. A portion of the cathode electrode 11 is connected to the peripheral P+ type diffusion layer 17 through the insulating film I2. With this connection, the peripheral light receiving element 6 is short-circuited with the semiconductor substrate 1, and unnecessary light absorbs the electricity generated in the peripheral light receiving element.
Avoid affecting the inner detection light receiving section.

Such a device is manufactured as follows.

First, for example, a 5i
An insulating film 12 such as No. 02 is grown, and a P medium-sized diffusion layer +8.14°15.16.17, which will become one pole of each of the light receiving elements 2, 8, and 4.5, is formed by photolithography. After growing the insulating film 12, the N-type diffusion region I8 and the N-type diffusion region 1, which will become the channel stopper I8, are grown.
form 9.

As described in MiJ, this improves the ohmic contact between the cathode electrode 11 and the semiconductor substrate 1, and improves the short circuit between the peripheral light receiving element 6 and the semiconductor substrate 1.

After growing the insulating film 12 again, holes are made through the insulating film 12 at necessary locations to form light receiving elements 2.8, 4.
forming electrode wirings 7°8.9.10 made of, for example, At which are connected to the contact portions 20, 20, 20°20 of No.5;
A cathode electrode 11 is formed which connects the N-type diffusion region 19 and the surrounding P+ type diffusion layer 17.

(Problem to be Solved by the Invention) In the conventional structure as described above, each light receiving element 2, 8
, 4.5 contact portions 20, 20 . ... are provided at the ends of each light-receiving element, so that the photocurrent generated at the portions away from the contact portions 20, 20 degrees, ... is transferred to the P+ type diffusion layer 18 on the light-receiving surface.
．． 14.15.16 Series resistance slows response time. Further, the N-type diffusion region I9, which becomes the contact portion between the cathode electrode 11 and the semiconductor substrate 1, is also connected to the peripheral light-receiving element 6.
Since it is provided at the end of the semiconductor substrate 1 leading to this
series resistor and P+ type diffusion layer 1 connected to it.
7 series resistors slow response time.

(Means for Solving the Problem) For example, a contact portion is formed along the long side of a P-type diffusion layer that becomes one pole of each surface of a plurality of light-receiving elements provided inside the surface of an N-type semiconductor substrate. A diffusion layer was provided along the inner periphery of the peripheral light-receiving element surrounding the plurality of light-receiving elements to connect the P-type diffusion layer serving as one pole on the surface thereof and the N-type semiconductor substrate.

(Function) With the above structure, the series resistance of the inner light receiving element and the surrounding light receiving elements can be reduced.

(Embodiment) Fig. 1 (,) is a plan view of one embodiment of the present invention.
Figure (b) is its AA' cross-sectional view. Figure 2(a).

The same parts as in (b) are given the same reference numerals. As shown in these figures, Fig. 2(a), ()+)
The differences from the conventional example are as follows.

P medium-sized diffusion layer + on the surface of the inner light receiving elements 2, 3, 4.5
8.14, 15.16 Long contact portions 20, 20, 20.20 are formed on the surface along the long sides, and electrode wirings 7, 8, 9.10 with kA are formed through the insulating film 12.
It is connected to the. In addition, the inner light receiving elements 2, 8, 4 .
A P-type diffusion layer on the surface of the peripheral light-receiving element 6 surrounding the 5! 7
An N-type diffusion region 19 is formed along the inner periphery. The N type diffusion region 19 short-circuits the P + type diffusion layer 17 and the N layer of the semiconductor substrate 1 over the entire inner circumference of the peripheral light receiving element 6 . A contact portion 19-1 is provided in a part of the N-type diffusion region I9.
is provided and wired to the cathode electrode +1 through the insulating film +2.

Such a device is manufactured by substantially the same process as the conventional example shown in FIGS. 2(a) and 2(b). Inner light receiving element 2,
The shape of the contact portions 20, 20, . It is different to make it longer.

The above description has been made regarding the case where the N-type semiconductor substrate 1 is used and the electrodes on the surfaces of the inner light-receiving elements 2, 3, 4.5 are anodes, but it is also possible to use a P-type semiconductor substrate. In that case, the aforementioned P type or N type becomes N type or P type, respectively.

(Effects of the Invention) Since the present invention has the above structure, the series resistance of the P-type layer or N-type layer of the inner light-receiving element group and the surrounding light-receiving elements is reduced, and the response of the element is increased. .

[Brief explanation of drawings]

FIG. 1(a) is a plan view of an embodiment of the present invention, and FIG. 1(b) is a plan view of an embodiment of the present invention.
) is a schematic sectional view, FIG. 2(a) is a plan view of the conventional example, and FIG.
Figure (b) is a schematic sectional view thereof. ■...Semiconductor substrate, 2, 8, 4.6... Light receiving element,
6... Peripheral light receiving element, 7, 8, 9. 10... Electrode wiring, 11... Cathode electrode, 12... Insulating film, 18
, 14°+5.16.17...P-type diffusion layer, 18.
・Channel stop flange 19...N-type diffusion region, 20・
・Contact part

Claims (1)

[Claims] 1. A semiconductor substrate of a second conductivity type, which consists of a plurality of light receiving elements provided inside the surface of a semiconductor substrate of a first conductivity type and peripheral light receiving elements surrounding them, and serves as one pole of the inner light receiving element. A contact portion is provided along the long side of the diffusion layer, and the second conductivity type diffusion layer serving as one pole of the surface thereof is connected to the first conductivity type semiconductor substrate along the inner periphery of the peripheral light receiving element. A light-receiving element characterized by being provided with a diffusion layer that