JPH02105572A - Solid state image pickup device - Google Patents

Abstract

PURPOSE:To prevent charge created in a region other than a photodetecting part from being transferred to a charge transfer part and suppress smear even if an intense light or a light refracted by an upper layer film on the photodetecting part is applied by a method wherein an insulating wall is provided between a photoelectric transducer region and a channel region. CONSTITUTION:In a solid state image pickup device, the photoelectric transducer region (photodiode region) 105 of a photodetecting part and the N-type channel region 106 of a charge transfer part are provided on a semiconductor substrate 101 with a reading part region between them. An insulating wall 103 having an aperture 113 is buried in the reading part region between the photodiode region 105 and the N-type channel region 106. The N-type channel region 106, therefore, is surrounded by an insulating silicon oxide film except the aperture 113. With this constitution, charge created in a P-type region 102 is almost drained into the N-type semiconductor substrate 101 and smear can be avoided.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a solid-state imaging device.

[Conventional technology]

A conventional solid-state imaging device, like the solid-state imaging device with a vertical overflow drain structure shown in FIG. A wall region 2) is formed, and the photodiode region 5 of the light receiving section and the N-type channel region 6 of the charge transfer section are two-dimensionally arranged in the same well of opposite conductivity type, and the area around the light receiving section is a readout area. A channel stopper 8 was formed except for the area 7. Furthermore, oxidation, CVD, etc. are repeated to form a thin silicon oxide film 9, a gate electrode 10, and a space between M and l.
1, light-shielding aluminum [12] was formed to form a solid-state image sensor.

[Problem to be solved by the invention]

In the conventional solid-state imaging device described above, strong light may be incident,
When light that is refracted by the film on the upper layer of the light-receiving section is incident, charges are generated in a region outside the light-receiving section, and when the charges move to the charge transfer section, there are drawbacks such as causing smear.

SUMMARY OF THE INVENTION An object of the present invention is to provide a solid-state imaging device that is free from smear caused by charges generated near a light receiving section.

[Means to solve the problem]

A solid-state imaging device of the present invention is a solid-state imaging device in which a photoelectric conversion element region of a light receiving section and a channel region of a charge transfer section are provided on a semiconductor substrate with a readout section region sandwiched therebetween. An insulating wall having an opening in the reading region is embedded between the region and the channel region.

〔Example〕

Next, the present invention will be explained with reference to the drawings.

FIGS. 1A and 1B are a cross-sectional view of a semiconductor chip and a plan view of a semiconductor substrate, respectively, showing a CCD solid-state imaging device having a vertical overflow drain structure according to an embodiment of the present invention.

In this embodiment, a photoelectric conversion element region (photodiode region 105) of a light receiving section and an N-type channel region 1 of a charge transfer section are used.
06 and the semiconductor substrate (N
In a solid-state imaging device provided in a type semiconductor substrate 101 with a well (P wall region 102), an opening 113 is formed in the above-mentioned readout region between the photodiode region 105 and the N-type channel region 106. 103 is embedded in the insulating wall having the following characteristics.

Next, the manufacturing method of this example will be explained.

A P wall region 10 is formed on an N type semiconductor substrate 101 made of silicon.
form 2. Furthermore, a groove is formed in a region that will become a charge transfer region in the future. Furthermore, a silicon oxide film is formed on the surface of the groove, leaving a region that will become a readout section in the future, using a photolithography technique using anisotropic etching. Furthermore, a P-type silicon layer 104 is grown to completely fill the void.

In the P-wall region 102, an N-type diffusion layer is formed as a photodiode region 105 of the light-receiving section, and a P-type silicon, Ill 0
4, an N-type channel region 106 of a charge transfer portion is formed, respectively. Then, a P-type diffusion layer serving as a channel stopper 108 is formed in a region around the light receiving section other than the readout region.

Furthermore, thin silicon oxide [
109, gate electrode 110. A J1 interlayer film 111 and a light-shielding aluminum film 112 are formed.

Since the N-type channel region 106 is surrounded by an insulating silicon oxide film except for the opening 113, the P-wall region 102
Almost all of the generated charges are discharged to the N-type semiconductor substrate 101, and smear is prevented.

FIG. 2 is a sectional view of a semiconductor chip showing a second embodiment.

The difference from the first embodiment is that there is no silicon oxide film at the bottom of the groove, and that an opening 213b or slit is also provided in the channel stopper 206 portion of the insulating wall 203b.

Since the smear is caused by charges generated in the vicinity of the photodiode region 205, there is no need to bury an insulating film under the N-type channel region 206. Since the channel stopper is of P+ type, the charge generated there hardly causes smear.

Next, the manufacturing method of this example will be explained.

A P wall region 202 is formed in an N type semiconductor substrate 201 as in the first embodiment. Then, a layer is formed in a region that will become a charge transfer region in the future, and a silicon oxide film or a silicon nitride film is formed on the main surface of the N-type semiconductor substrate 201 and the surface (side surface and bottom surface) of the layer.

Then, an insulating film is formed by anisotropic etching as shown in the figure. Furthermore, by epitaxial growth, a P-type silicon film 20 is formed.
Grow 4 and completely fill the gap. The P wall region 102 has a photodiode region 205 which becomes a light receiving part, and the P type silicon film 204 has an N type channel region 2 which becomes a charge transfer part.
06 respectively. In addition, there are channel stoppers 208 in the area around the light receiving area other than the readout area.
P-type expanded FII1. fr! Form I. Furthermore, oxidation, CVD, etc. are repeated to form a thin oxide film 209. Gate electrode 210 interlayer film 211. Aluminum 212 is formed.

Since there is a silicon oxide film at the bottom of the groove, the P-type silicon film tends to be a single crystal, and the performance of the charge transfer section is not likely to be deteriorated by providing an insulating wall.

〔Effect of the invention〕

As explained above, the present invention provides a solid-state imaging device in which a light receiving section, a reading section, and a charge transfer section are arranged two-dimensionally.
An insulating wall is provided in the region between the photoelectric conversion element region and the channel region, so when strong light or light refracted by the upper layer film on the light receiving section enters, charges generated in areas other than the light receiving section are removed. 5, 105, 205... Photodiode region, 6, 106, 206... N-type channel region, 7...
・Readout region, 8.108,208...Channel stopper, 9,209.309...Thin silicon oxide film, 10,110,210...Gate electrode, 1.1
, 111.211... interlayer film, 12,112°212
...Light-shielding aluminum film, 113, 213a, 213b
...Open hole.

Claims (1)

[Claims] In a solid-state imaging device in which a photoelectric conversion element region of a light receiving section and a channel region of a charge transfer section are provided on a semiconductor substrate with a readout section region in between, there is a gap between the photoelectric conversion element region and the channel region. A solid-state imaging device characterized in that an insulating wall having an opening is embedded in the readout region.