JPH0321083A - Photodiode - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

Detailed Description of the Invention (Industrial Field of Application) The present invention relates to an apparatus for forming a plurality of light-receiving elements in parallel on a single semiconductor substrate and detecting the amount of light irradiated onto the light-receiving elements. It is about improvement.

(Prior art) A plurality of light receiving elements are formed in parallel on a single semiconductor substrate,
An example of a conventional photodiode that irradiates these light receiving elements with light and detects the amount of light irradiated onto each light receiving element is shown in FIGS. 8(a) and 8(b). 7 Photodiodes are generally manufactured by forming a P+N or N+P junction on a semiconductor substrate.

Figure 8(a) is a plan view, and Figure 3(b) is its C.
C' is a schematic cross-sectional view. As shown in FIGS. 8(a) and 8(b), a circular light-receiving element 2 is formed approximately in the center of the semiconductor substrate 8, and approximately rectangular light-receiving elements are formed at intervals on the outside thereof. 1 is formed. Between each of the light receiving elements 1 and 2, an annular separation dead zone 7 made of a dark photodiode is formed.

The dimensions of each part in FIGS. 8(.) and (b) do not necessarily match for convenience of explanation. The light-receiving elements 1 and 2 are provided with electrodes 10 and 11, respectively, and are connected to an external circuit at the periphery of the element, and a short-circuiting electrode 12 is provided over substantially the entire circumference of the separation dead zone 7K.

Such a device is manufactured as follows. 1. First, an insulating film 4 such as Si02 is formed on the surface of an N-type (f or P-type) semiconductor substrate 3, and P+ ('t7' t is N+)
Diffusion areas 5, 6 and separation insensibility. After shaping the P+ (t or N+) diffusion region 8 that will become one pole of the dummy 7 photodiode in the band 7 and growing the insulating film 4 again, the dummy 7 in the separation dead zone 7 between the light receiving elements 1 and 2 is formed. An N+ (1 or p+) diffusion region 9 is formed to short-circuit the photodiode. Then, after making the insulating film 4 a certain length again, the light receiving element 1
and electrodes 10 and 11, for example of At, for one pole of 2;
In addition, there is a short-circuit of, for example, At, between the P+ (1 or N+) diffusion region 8 and the N+ (1 or p10) diffusion region 9 of the ξ-photodiode, which short-circuits them and also serves as a light shield. By forming the electrode 12, a structure as shown in FIGS. 8(a) and 8(b) is obtained.

(Problem to be Solved by the Invention) In the conventional structure described above, the separation dead zone 7 is formed over almost the entire area between each of the light receiving elements 1 and 2 in order to reduce crosstalk between each of the light receiving elements 1 and 2. ing.

As shown in FIG. 8(a), the outer light receiving element 1 is formed to surround the inner light receiving element 2, and the entire area between the light receiving elements 1 and 2 is P+(1 or N+ ) Since the diffusion region 8 and the N+ (1 or P+) diffusion region 9 were formed and short-circuited by the shorting electrode 12, the spacing between each light receiving element was approximately 150 to 2
00 μm is required, which increases the size of the device.

(Means for Solving the Problems) In order to eliminate the above-mentioned drawback of widening the distance between the light receiving elements, the present invention provides a separation dead zone formed between one light receiving element and the other light receiving element. A portion that short-circuited the P layer and the N layer was provided only in one part.

(Function) Since the present invention has the above-described structure, there is no need to form a short-circuiting electrode over the entire space between each light receiving element.

The carriers generated in the adjacent light-receiving and diffusing parts of each light-receiving element are blocked by the P+ or +a N''' diffusion layer provided in the separation dead zone and absorbed by the short-circuited dummy photodiode, which reduces the influence of crosstalk. can be reduced.

(Embodiment) FIG. 1(a) is a plan view of an embodiment of the present invention, FIG. 1(b) is a schematic sectional view taken along line A-A', and FIG.
'It is a schematic cross-sectional view. The same parts as those shown in FIGS. 3(.) and (b) are given the same reference numerals.

The difference from Fig. 8 (a) and (b) is the separation dead zone Iku 7.
As shown in FIGS. 1(a) and 1(b), the separation dead zone 7 between the inner light-receiving element 2 and the outer light-receiving element 1 has a Dagu diode structure over most of it. Annular P+C or N+) diffusion region 8 which becomes one electrode
and a ring-shaped Ni
or p+) diffusion region 9, an insulating film 4 formed thereon, and a light shielding layer 14 made of, for example, At, covering the surface of the insulating film 4.

Then, these P+ (1 or N+) diffusion regions 8 and N+
What is the (1 or p+) diffusion region 9? Fig. 1 (a) and (C)
As shown in FIG. 1, a part of the insulating film 4 is removed from a part of the two annular diffusion regions 8 and 9, and the short-circuiting electrode 15 is used to short-circuit the two annular diffusion regions 8 and 9.

Such a device is produced, for example, as follows. Previously, S was formed on the surface of the N (t or P) type semiconductor substrate 3.
An insulating film 4 such as i02 is grown, and the inner and outer light receiving elements 1 are
and P+ (4 or N+) diffusion region 5 which becomes one pole of 2.
.
After applying the Si02 insulating film 4 on the surface again,
A da<--
An N+ (4 or p+) diffusion region 9, which becomes part of a photodiode, is formed along a P+ (t or N+) diffusion region 8. At this time, in the part where the width of the P+ (1 or N+) diffusion region 8 is wide, the width of the N+ (t or p+) diffusion region 9 is also wide, and the width of the P+ (1 or N+) diffusion region 8 is also wide. Allow a portion to be exposed to the surface. After growing the insulating film 4 again, a light-shielding layer 14 covering the AtK electrodes 10 and 11 of the light-receiving elements 1 and 2 and most of the separation dead zone 7 between the light-receiving elements 1 and 2, and a P+( A short-circuiting electrode 15 is formed to short-circuit part of the t or N+) diffusion region 8 and the N+ (t or p+) diffusion region 9. The light shielding layer 14 and the short-circuiting electrode 15 can be integrally formed using At at the same time.

FIG. 2 is a schematic cross-sectional view of another embodiment, in which the diffusion region 9 of the dummy photodiode in the separation dead zone 7 in FIG. 1(b) is omitted. However, in another part of the separation dead zone 7, P and N diffusion regions 8 and 9 are formed and short-circuited, as in the case of FIG. 1(C) and 1iJj.

(Effects of the Invention) Since the present invention has the above-described structure, carriers generated in the adjacent light-receiving surface diffusion portion of each light-receiving element are absorbed by the dummy photodiode in the separation dead zone, and each light-receiving element attempts to detect them. Since it is possible to reduce the influence of crosstalk on the output with respect to the amount of light and to narrow the width of the separation dead zone, it is possible to reduce the size of the entire device. For example, Fig. 1 (a), (b), (
In cases like c), the width of the separation dead zone should be approximately 80 to 10
In the case of the fx structure as shown in FIG. 2, the width can be reduced to about 50 μm.

[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 taken along the line A-A', FIG.
1 is a plan view of a conventional example, and FIG. DESCRIPTION OF SYMBOLS 1... Light receiving element, 2... Light receiving element, 8... Semiconductor substrate, 4... Insulating film, 5... Light receiving surface diffusion part, 6...
Light-receiving surface diffusion section, 7...Separation dead zone section, 8...P
('t or N) diffusion region, 9...N (-1 or P
) Diffusion region, 10... Electrode, 11...\i''. Pole, 12... Short circuit electrode, 14... Light shielding layer, 15...
Short circuit electrode 0 8 0) Culture

Claims (1)

[Claims] 1. Consists of a plurality of light receiving elements formed on one substrate and a separation dead zone formed between them, the separation dead zone has a PN junction, and only a part of the separation dead zone has a PN junction.
A photodiode characterized by a shorted junction.