CN100435343C - Solid-state image sensing device and camera system using the same - Google Patents
Solid-state image sensing device and camera system using the same Download PDFInfo
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- CN100435343C CN100435343C CNB2005101287688A CN200510128768A CN100435343C CN 100435343 C CN100435343 C CN 100435343C CN B2005101287688 A CNB2005101287688 A CN B2005101287688A CN 200510128768 A CN200510128768 A CN 200510128768A CN 100435343 C CN100435343 C CN 100435343C
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Abstract
A solid-state image sensing device includes a plurality of pixels. Each pixel has a photodiode, a first transistor, and a second transistor. The photodiode is constituted by a first-conductivity-type semiconductor region and a second-conductivity-type semiconductor region. The first and second conductivity types are opposite to each other. The first transistor has a first-conductivity-type drain region formed in the second-conductivity-type semiconductor region to transfer signal charge to the drain region. The second transistor has a source region and a drain region which are formed in the second-conductivity-type semiconductor region and which have the first conductivity type. At least one second-conductivity-type potential barrier is provided under the drain region of the first transistor and the source region and/or the drain region of the second transistor.
Description
The application is that June 27, application number in 2003 are 03148475.1, denomination of invention is solid-state image pickup device the applying date and dividing an application with the application of the camera system of solid-state image pickup device.
Invention field
The present invention relates to solid-state image pickup device and with the camera system of solid-state image pickup device.
Background technology
In recent years, the needs of importing with imaging device as the image that with digital still gamma camera, video camera encoder is the center for solid-state image pickup device increase rapidly.
Using CCD (Charge Coupled Device: charge coupled cell) and MOS type solid-state image pickup device as these solid-state image pickup devices.The former with the latter relatively, because highly sensitive noise is little, so the imaging device as high image quality is popularized, but its reverse side is, it is big to have power consumption, the driving voltage height is so because do not use general semiconductor fabrication process cost height, be difficult to the weakness of the peripheral circuit etc. of integrated drive electronics etc.
Owing to above-mentioned reason, also developing the MOS type solid-state image pickup device of scale-up version so far always.The solid-state image pickup device of scale-up version be will in optical diode, store signal charge import the control electrode of the amplifier transistor that has in the pixel, the device of exporting accordingly from the main electrode amplification of amplifier transistor and output and signal charge amount.Particularly as the solid-state image pickup device of scale-up version, using in the exploitation of mos sensor of MOS transistor and dropping into strength as amplifier transistor.
The MOS type solid-state image pickup device that our anticipation can overcome the weakness of above-mentioned CCD will be applicable to the application that enlarges from now in the portable set that needs envisioning.
Figure 13 is the circuit diagram of expression as the typical case of the cmos sensor pixel of solid-state image pickup device.
30 is unit pixel in Figure 13, the 1st, be used to store optical diode by the signal charge of incident light generation, the 6th, output is amplified the amplifying mos transistor of output signal accordingly with the signal charge amount, the 3rd, the diffusion of floating that is connected with the grid of the amplifying mos transistor 6 of acknowledge(ment) signal electric charge (below be designated as FD) zone, the 2nd, the signal charge that is used for storing at optical diode 1 is sent to the transmission MOS transistor in FD zone 3, the 4th, be used to the reset mos transistor that FD zone 3 is resetted, the 5th, be used to select to export the selection MOS transistor of pixel, 9a is used for adding pulse on the grid that transmits MOS transistor 2, the control line that electric charge transmission work is controlled, 9b is used for adding pulse on the grid of reset mos transistor 4, the control line that the work that resets is controlled, 9c is used for adding pulse on the grid of selecting MOS transistor 5, the control line that selection work is controlled, 10a is connected with the drain electrode of amplifying mos transistor 6 and the drain electrode of reset mos transistor 4, to the power supply wiring of their supply power current potentials.10b is the output line, the 8th of the amplifying signal of the pixel selected of output, and as current source work, amplifying mos transistor 6 and the constant current that forms source follower are to make MOS transistor 8 carry out the distribution of grid of the current potential supply MOS transistor 8 of constant current work with MOS transistor, 10c.Above-mentioned pixel 30 assortments are become the pixel area of the rectangular formation 2 dimension solid-state image pickup devices of 2 dimensions, but output line 10b becomes the common line of the pixel of each row in this matrix constitutes, control line 9a, 9b, 9c become the common line of pixel of each row respectively, and only the pixel of the row of being selected by control line 9c is to output line 10b output signal.
And Figure 14 is the figure of other pixel circuit of the existing solid-state image pickup device of expression.In Figure 14, the 1st, optical diode, the 2nd, the transmission MOS transistor of the electric charge of transmission optical diode, the 3rd, temporary transient storage transmits the floating diffusion region territory of electric charge, the 4th, be used to the reset mos transistor that floating diffusion region territory and optical diode are resetted, the 5th, be used for selecting the selection MOS transistor of any delegation of array, the 6th, the source follower MOS transistor that becomes voltage to amplify the charge-voltage converting in floating diffusion region territory with source follower type amplifier, the 7th, commonization read the sense wire of pixel voltage signal in 1 row, the 8th, be used to make sense wire 7 to flow through the constant current source of constant current.
We illustrate working condition simply now.By optical diode 1 incident light is transformed into electric charge, by transmit MOS transistor 2 with charge storage in floating diffusion region territory 3.Make floating diffusion region territory 3 and optical diode 1 reset to certain potentials because open reset mos transistor 4 in advance and transmit MOS transistor 2, so the current potential in floating diffusion region territory 3 correspondingly changes with the electric charge that is produced by incident light.The current potential in floating diffusion region territory 3 is amplified by source follower MOS transistor 6, outputs to sense wire 7.Select MOS transistor 5 to select this pixel by opening.Pass through the reset potential in floating diffusion region territory 3 and the Difference Calculation of the current potential after the light signal storage in the unillustrated in the drawings output circuit, sensed light signal.
Figure 15 is the pattern sectional view of the solid-state image pickup device of Figure 13.In addition, Figure 15 is the pattern sectional view that comprises optical diode, transmits the cross section in MOS transistor and FD zone.In Figure 15, the 11st, N type semiconductor substrate, the 12nd, P type trap, the 15th, forms optical diode by P type trap 12 and N type semiconductor zone 15 at the N type semiconductor zone that forms in P type trap 12, store the signal charge by the incident light generation in N type semiconductor zone 15.The 18th, by the FD zone, the 14th that the N type semiconductor zone that forms in P type trap 12 constitutes, the grid of transmission MOS transistor 2 shown in Figure 13, in addition, FD zone 18 also is the drain region of transmitting MOS transistor.In addition, the source region of transmission MOS transistor is N type semiconductor zone 15.The 20th, with FD zone 18 distributions that are connected, be connected with the grid of unillustrated amplifying mos transistor among the figure.The 17th, the element that is called locos oxide film separates with dielectric film, the 29th, and impurity concentration is than the raceway groove barrier layer of separating at element with the high P+ type of the P type trap 12 of 17 times formation of dielectric film.
Figure 16 is the pattern sectional view of solid-state image pickup device shown in Figure 14.This cross section Figure 16 is the optical diode 1 of expression Figure 14 and the figure that transmits the part of MOS transistor 2.The 11st, n type silicon chip, the 12nd, P type trap, 13a is the grid oxidation film of MOS transistor, 13b is the thin oxide film on light accepting part divides, the 14th, the grid of transmission MOS transistor, the 15th, the N type negative electrode of optical diode 1, the 16th, in order to have the surperficial p type island region territory of imbedding the optical diode structure, the 17th, be used for the locos oxide film that element separates, the 18th, form the N type area with high mercury that the floating diffusion region territory also becomes the drain region of transmitting MOS transistor 2, the 19th, make the silicon oxide layer of the 1st layer of insulation of grid and metal, the 20th, contact plug, the 21st, the 1st layer on metal, the 22nd, make the interlayer dielectric of the 1st layer on metal and the 2nd layer of insulation of metal, the 23rd, the 2nd layer on metal, the 24th, make the interlayer dielectric of the 2nd layer on metal and the 3rd layer of insulation of metal, the 25th, the 3rd layer on metal, the 26th, passivating film.At colour with in the photo-electric conversion device, on the upper strata of passivating film 26 further unillustrated color-filter layer among the formation figure, be used for further improving the lenticule of sensitivity.By there not being the opening portion of the 3rd layer on metal, enter optical diode from the light of surperficial incident.Light is absorbed in the N of optical diode type negative electrode 15 or P type trap 12, generates electron hole pair.Wherein electron storage is at N type cathode zone.
In addition, in United States Patent (USP) 6403998, disclose the p type embedding layer that forms institute's depthkeeping degree from n type substrate, on the n of its upside type substrate, formed the solid-state image pickup device of light-to-current inversion part.
And, in United States Patent (USP) 6504193, disclosed an end that is formed extended at both sides optical diode up to the bottom of reading grid, formed the solid-state image pickup device of break-through barrier region in the bottom of the input part suitable for grid from coupling ground with the drain region.
But in the situation of the existing structure of Figure 15, Figure 16, the part of the signal charge that produces below optical diode is not absorbed by optical diode, and is absorbed by the transistorized source drain zone in FD zone 18 and the pixel.As a result, sensitivity is reduced.
In addition, although CMOS type solid-state image pickup device has been carried out various improvement, still exist the low such problem of device medium sensitivity at especially little pixel size.Even if providing with fine pixel according to new structure, the present invention also can access highly sensitive CMOS type solid-state image pickup device.
Below our explanation in the low reason of existing structure medium sensitivity of Figure 16.Figure 16 produces electronics by the light 27 that incides opening portion successfully to be stored in N type cathode zone, carry out work as effective signal charge, but for example the electronics that produce in the position of how much leaving from optical diode like that of light 28 are not at N type cathode zone, and the situation of being caught by the lower N+ type floating diffusion region territory 18 of electromotive force.In addition, even if optical diode directly below because diffusion and trapped electron repeatedly, the result is with certain probability, electronics is absorbed by the zone of the low potential beyond the optical diode, to the not contribution of light-to-current inversion signal.If on more deep-seated is put for silicon face, form N type negative electrode 15, then collect the electronics that produces by optical diode easily, but because N type cathode zone forms by inject ion in P type well area 12, so impurity concentration can not be too low.N type negative electrode 15 is done such restriction owing to be subjected to exhausting chemical industry, can not be taken at the structure that quite dark position forms high concentration, and this is the problem of existing structure.
Like this, because there is boundary in the volume of the N type negative electrode that becomes optical diode, so it is abundant inadequately to collect the ability of the electronics that is produced by incident light, thereby sensitivity is low.
In addition, even if in the existing structure that in United States Patent (USP) 6403998, discloses, also exist because of the bottom of reading grid at signal potential barrier is set, so the electronics that still can not prevent to be produced in dark position by incident light is made the problem of sensitivity reduction by 18 absorptions such as grade of floating diffusion region territory.
In addition, even if in the existing structure that in United States Patent (USP) 6504193, discloses, also exist because the break-through barrier region only is formed on the bottom of input part, so can not prevent the part of the electronics that produced by incident light is absorbed by other the transistorized source electrode in the pixel, drain electrode and to the absorption in abutting connection with pixel, makes the problem of sensitivity reduction equally.
A kind of optimization floating P+area photoelectric diode that is used for cmos image sensor is disclosed in Chinese patent (CN1305229A), wherein on P type semiconductor substrate 101, designed the components of photo-electric conversion and element separated region 113, be configured the N type semiconductor zone 103 adjacent element separated regions of the formation components of photo-electric conversion.But in such structure, because of the electric charge that defective produced of element separated region, be blended in the N type semiconductor zone 103, will in picture signal, produce noise from the electric charge of adjacent pixels.
Though in Chinese patent (CN1305229A), put down in writing the structure that on P type semiconductor substrate 101, has designed the components of photo-electric conversion and element separated region 113, but will on the N type semiconductor zone 103 that constitutes the components of photo-electric conversion, sneak into the electric signal that becomes noise from the P type semiconductor substrate in the structure that has designed the components of photo-electric conversion on such P type semiconductor substrate 101.
Therefore, in the present invention, its purpose is to reduce electric charge from the element separated region, sneaking into from the electric charge of adjacent pixels.In addition, its purpose of the present invention is reducing from the sneaking into of the electric charge that becomes noise of semiconductor substrate, and reduces sneaking into from the electric charge of adjacent pixels.
Summary of the invention
Even if the purpose of this invention is to provide with the also very high solid-state image pickup device of small pixel sensitivity, it is low that another object of the present invention provides driving voltage low in energy consumption, cheaply camera system.
The invention provides a kind of solid-state image pickup device, have a plurality of pixels, this pixel comprises the optical diode that the 2nd semiconductor regions by the 1st semiconductor regions of the 1st conductivity type and 2nd conductivity type opposite with the conductivity type of the 1st conductivity type constitutes, and described the 2nd semiconductor regions is as source electrode or drain region and bring into play the transistor of the 2nd conductivity type of function, it is characterized in that, between the above-mentioned optical diode of adjacency, be formed with dielectric film is formed at element separated region in the ditch, be formed with the 3rd semiconductor regions of the 1st conductivity type along the side of said elements separated region, be formed with the 4th semiconductor regions of the 1st conductivity type in the bottom of said elements separated region.
In technique scheme, owing between the optical diode of adjacency, have dielectric film is formed at element separated region and the 4th semiconductor regions in the ditch, therefore compare with Chinese patent (CN1305229A), can realize and the separating of adjacent pixels.And then, owing to have the 3rd semiconductor regions, therefore can reduce the influence of the dark current that produces owing to element separated region with ditch.
In addition, the invention provides a kind of solid-state image pickup device, it is characterized in that, have a plurality of pixels, be configured in the element separated region between the above-mentioned pixel of adjacency and the semiconductor substrate of above-mentioned the 2nd conductivity type; Above-mentioned pixel comprises: from the photoelectric conversion department of the 4th semiconductor regions that light inlet side is disposed with the 1st semiconductor regions that is made of the 1st conductivity type, the 2nd semiconductor regions that is made of the 2nd conductivity type opposite with the conductivity type of the 1st conductivity type, impurity concentration constitute than low the 3rd semiconductor regions that is made of the 2nd conductivity type of above-mentioned the 2nd semiconductor regions and by the 1st conductivity type; With the transistor of source electrode with the 2nd conductivity type and drain region, this solid-state image pickup device also has the 5th semiconductor regions of the 1st conductivity type that is configured in above-mentioned transistorized grid bottom and is configured in the 6th semiconductor regions of the 1st conductivity type under the said elements separated region; Surround above-mentioned the 3rd semiconductor regions by above-mentioned the 4th semiconductor regions, above-mentioned the 5th semiconductor regions and above-mentioned the 6th semiconductor regions.
The invention provides a kind of solid-state image pickup device, it is characterized in that, have a plurality of pixels, be configured in the element separated region between the above-mentioned pixel of adjacency and the semiconductor substrate of above-mentioned the 2nd conductivity type; Above-mentioned pixel comprises: from the photoelectric conversion department of the 4th semiconductor regions that light inlet side is disposed with the 1st semiconductor regions that is made of the 1st conductivity type, the 2nd semiconductor regions that is made of the 2nd conductivity type opposite with the conductivity type of the 1st conductivity type, impurity concentration constitute than low the 3rd semiconductor regions that is made of the 2nd conductivity type of above-mentioned the 2nd semiconductor regions and by the 1st conductivity type; With the transistor of source electrode with the 2nd conductivity type and drain region, this solid-state image pickup device also has the 1st potential barrier of the 1st conductivity type that is configured in above-mentioned transistorized grid bottom and is configured in the 2nd potential barrier of the 1st conductivity type under the said elements separated region; Surround above-mentioned the 3rd semiconductor regions by above-mentioned the 4th semiconductor regions, above-mentioned the 1st potential barrier and above-mentioned the 2nd potential barrier.
In addition, in technique scheme, has the 2nd conductive-type semiconductor substrate.Therein, owing to by the 4th semiconductor regions, the 5th semiconductor regions, the 6th semiconductor regions the 3rd semiconductor regions is surrounded, so can reduce noise.In addition, owing to by the 4th semiconductor regions, the 1st potential barrier, the 2nd potential barrier the 3rd semiconductor regions is surrounded, so can reduce noise.
In order to solve above-mentioned problem, the 1st solid-state image pickup device of the present invention, have the optical diode that constitutes by the 1st conductive-type semiconductor region and the 2nd conductive-type semiconductor region opposite with the conductivity type of above-mentioned the 1st conductive-type semiconductor region in a plurality of assortments, has the 1st conductivity type drain region that in above-mentioned the 2nd conductive-type semiconductor region, forms, the signal charge that will produce in above-mentioned optical diode is sent to the 1st transistor of above-mentioned drain region, in the solid-state image pickup device of the 2nd transistorized pixel, the potential barrier of the 2nd conductivity type is set in the bottom of the bottom of above-mentioned the 1st transistorized above-mentioned drain region and the above-mentioned the 2nd transistorized above-mentioned source region and/or above-mentioned drain region with the 1st conductivity type source electrode drain region that in above-mentioned the 2nd conductive-type semiconductor region, forms.
In addition, the 2nd solid-state image pickup device of the present invention, in the solid-state image pickup device that the optical diode that is made of the 2nd conductive-type semiconductor region that has by the 1st conductive-type semiconductor region and the conductivity type opposite with above-mentioned the 1st conductivity type and transistorized pixel with the 1st conductivity type source electrode drain region that forms constitute, the potential barrier of the 2nd conductivity type is set in the bottom of above-mentioned transistorized grid in above-mentioned the 1st conductive-type semiconductor region.
In addition, the 3rd solid-state image pickup device of the present invention, have the 1st conductivity type substrate, the 2nd conductive layer and the 1st conductive layer, form in the solid-state image pickup device of optical diode by above-mentioned the 2nd conductive layer and above-mentioned the 1st conductive layer, around the zone that forms above-mentioned optical diode, form the potential barrier that constitutes by the 2nd conductive area.
In addition, the feature of the 4th solid-state image pickup device of the present invention is the depth direction that the 2nd conductive area multilayer ground that will form potential barrier is configured in the 1st conductive layer of formation optical diode.
In addition, the feature of the 5th solid-state image pickup device of the present invention be form the superiors' control in the multilayer of potential barrier from optical diode to transmitting transistorized electric charge transfer path.
In addition, the feature of the 6th solid-state image pickup device of the present invention is in the 1st conductive layer at least in the opposite conductivity type embedding layer degree of depth nearby, because cingens opposite conductivity type layer reduces impurity concentration.
In addition, the feature of the 7th solid-state image pickup device of the present invention is that the 1st conductive layer has near semiconductor surface the part, than the high zone of other parts impurity concentration.
In addition, the feature of the 8th solid-state image pickup device of the present invention be when transmitting electric charge the 1st conductive layer by exhausting fully.
In addition, the feature of the manufacture method of the 1st solid-state image pickup device of the present invention is after epitaxial growth forms the 1st conductive layer on the opposite conductivity type embedding layer, injects by ion to form the opposite conductivity type layer.
In addition, the feature of the manufacture method of the 2nd solid-state image pickup device of the present invention is that the opposite conductivity type embedding layer is carry out the ion injection in the semiconductor chip of the 1st conductivity type after, injects by ion to form the opposite conductivity type layer.
And the feature of the 9th solid-state image pickup device of the present invention is that the separated region between the pixel of adjacency forms by STI (Shallow Trench Isolation (shallow ridges separation)).
And the feature of the 10th solid-state image pickup device of the present invention is to be covered fully by the semiconductor layer of the 1st conductivity type with the oxide-film of the STI formation of separated pixels and the contact-making surface of silicon.
And the feature of the 11st solid-state image pickup device of the present invention is that the separated region between the pixel of adjacency separates (Deep Trench Isolation) by zanjon and forms.
And the feature of the 12nd solid-state image pickup device of the present invention is to be covered fully by the semiconductor layer of the 1st conductivity type with the oxide-film of the separation of the zanjon between the pixel that separates adjacency formation and the contact-making surface of silicon.
The effect of the 1st solid-state image pickup device of the present invention is because by potential barrier being arranged on below FD zone and each transistorized source drain, the signal charge that produces below potential barrier is not absorbed by FD zone and each the transistorized source drain zone that is provided with potential barrier, so improved sensitivity.
Even if the effect of the 2nd solid-state image pickup device of the present invention is arranged on potential barrier below the grid of the N transistor npn npn that forms pixel and holds concurrently and play and prevent to be short-circuited between source electrode, drain electrode and the N transistor npn npn also can be worked in the N type semiconductor zone effect.
The effect of the 3rd solid-state image pickup device of the present invention is by producing potential barrier to electronics with the embedding layer with opposite conductivity type with N type layer that the layer of this embedding layer same conductivity surrounds optical diode, form the low bulky optical diode of impurity concentration simultaneously, the collection power of collecting the light signal electronics is increased.
The effect of the 4th solid-state image pickup device of the present invention is that the N type layer of optical diode is very dark, promptly has in the structure of sensitivity in long wavelength's one side more, by a plurality of P type of lamination layer, also can form effective potential barrier.
The effect of the 5th solid-state image pickup device of the present invention is can realize can positively sending structure from the signal of optical diode by transmitting transistor.
The effect of the 6th solid-state image pickup device of the present invention is when adding reverse blas on optical diode when store charge, and depletion layer extends to N type layer one side effectively, and easy realization is exhausting fully.In in-plane, be on the roughly the same position by this trap layer and this embedding layer, can enough optical masking operations still less obtain high separating effect.
The effect of the 7th solid-state image pickup device of the present invention is that the electron potential by making semiconductor surface is lower than other parts, makes electronics concentrate near surface when store charge, is difficult to occur transmitting remaining when passing on electric charge.
The effect of the 8th solid-state image pickup device of the present invention is according to the reverse blas that is added on the optical diode that is surrounded by the opposite conductivity type layer, the decision concentration degree of depth for exhausting, and forming does not have reset noise, the optical diode of transmission type fully.
The effect of the manufacture method of the 1st solid-state image pickup device of the present invention is to make the solid-state image pickup device corresponding with all dichroisms by changing the thickness of epitaxially grown layer.
The effect of the manufacture method of the 2nd solid-state image pickup device of the present invention is when when long wavelength's one side does not need high significantly spectral sensitivity, the enough ion implantation of energy, uniform embedding layer in depth direction forms the good face of reproducibility.
The effect of the 9th solid-state image pickup device of the present invention is can provide to use STI, even if also can suppress to bleed in abutting connection with the electric charge between picture in fine pixel, it is little to crosstalk, highly sensitive photography element.
The effect of the 10th solid-state image pickup device of the present invention does not form depletion layer at the interface of oxide-film silicon, the photography element that the noise in the time of can forming dark is few by in STI.
The effect of the 11st solid-state image pickup device of the present invention is to be provided at the separation property that further improves in the fine pixel between pixel, and it is little to crosstalk, highly sensitive photography element.
The effect of the 12nd solid-state image pickup device of the present invention is by in zanjon separates, and does not form depletion layer at the interface of oxide-film silicon, the photography element that the noise in the time of can forming dark is few.
Description of drawings
Fig. 1 is the pattern sectional view of the solid-state image pickup device of the 1st example of the present invention.
Fig. 2 is the pattern sectional view of the solid-state image pickup device of the 2nd example of the present invention.
Fig. 3 is the pattern sectional view of the solid-state image pickup device of the 3rd example of the present invention.
Fig. 4 is the pattern sectional view of the solid-state image pickup device of the 4th example of the present invention.
Fig. 5 is the pattern sectional view of the solid-state image pickup device of the 5th example of the present invention.
Fig. 6 is the pattern sectional view of the solid-state image pickup device of the 6th example of the present invention.
Fig. 7 is the pattern sectional view of the solid-state image pickup device of the 7th example of the present invention.
Fig. 8 is the pixel plane figure according to solid-state image pickup device of the present invention.
Fig. 9 is the pattern sectional view of the solid-state image pickup device of the 8th example of the present invention.
Figure 10 is the pattern sectional view of the solid-state image pickup device of the 9th example of the present invention.
Figure 11 is the part according to the circuit diagram of solid-state image pickup device of the present invention.
Figure 12 is the block diagram of using according to the camera system of solid-state image pickup device of the present invention.
Figure 13 is the circuit diagram of expression as the typical case of the cmos sensor pixel of solid-state image pickup device.
Figure 14 is the figure of the pixel circuit of the existing solid-state image pickup device of expression.
Figure 15 is the pattern sectional view of solid-state image pickup device shown in Figure 13.
Figure 16 is the pattern sectional view of solid-state image pickup device shown in Figure 14.
Embodiment
(the 1st example)
Fig. 1 is the pattern sectional view of the solid-state image pickup device of the 1st example of the present invention.
In Fig. 1,101 is semiconductor chips, the 102nd of the 1st conductivity type (here as be illustrated as N type), as the P type trap, the 103rd of the 2nd conductive-type semiconductor region, as the N type semiconductor zone of the 1st conductive-type semiconductor region that forms, forms optical diode by P type trap 102 and N type semiconductor zone 103, stores the signal charge by the incident light generation in N type semiconductor zone 103 in P type trap 102.The 111st, in the drain region of transmitting transistorized the 1st conductivity type of transmission of the signal charge that produces in the optical diode, be the FD zone in the N type semiconductor zone of formation in P type trap 102 as the 1st transistor.The 109th, transmit transistorized grid, N type semiconductor zone 103,111 also is respectively to transmit transistorized source electrode, drain region.The 113rd, with N type semiconductor zone 111 distributions that are connected, be connected with grid 130 as the 2nd transistorized amplifier transistor.In addition, amplifier transistor has the formation that forms grid 130 between 131 drain regions 132, source region.The 133rd, the vertical signal line that is connected with source electrode 131.In addition, 132 also is the drain electrode of amplifier transistor, also is as other transistorized source region of the 2nd transistorized selection.The 134th, select transistor drain, between source drain, form grid 135.The 136th, with the drain line of selecting transistor drain 134 to be connected.The 107th, by the film formed dielectric film, the 106th that is used for resolution element of thick oxidation, the P+ type raceway groove barrier layer, the 105th that impurity concentration is higher than the P type trap that forms below the dielectric film 107 that is used for resolution element 102, the potential barrier that forms in P type semiconductor zone with P type trap 102 same conductivity.
In addition, in this manual, will transmit transistor as the 1st transistor, the transistor beyond the transmission transistor that will form in pixel is expressed as the 2nd transistor.
In addition,, after transmission, make N type semiconductor zone 103 exhausting immediately like that in N type semiconductor zone 103, on N type semiconductor zone 103, set N type impurity concentration for the signal charge that will store when the transmission work is sent to FD zone 111.
In addition, in the solid-state image pickup device of this example, 1 pixel is made of optical diode, transmission transistor, amplifier transistor and selection transistor, but the formation of 1 pixel is not limited to this example.For example, 1 pixel also can be made of optical diode, transmission transistor and amplifier transistor.Perhaps 1 pixel also can be made of optical diode, transmission transistor, amplifier transistor, selection transistor and reset transistor.
The feature of potential barrier 105 of the present invention be arranged on below the 1st transistor drain zone and the 2nd transistorized source electrode and/or drain region below.When forming a plurality of the 2nd transistor, source electrode and/or drain region more than at least 1 are set.
In addition, the impurity concentration of potential barrier 105 is P+ types higher than the impurity concentration of P type trap 102.In addition, raceway groove barrier layer 106 all is the semiconductor regions of identical P+ type with potential barrier 105, but their impurity concentration can certainly be different, and potential barrier 105 is for example injected by ion boron and gallium are injected 102 settings of P type trap.
As the present invention, because by potential barrier 105 being arranged on below FD zone and each transistorized source drain, the signal charge that produces below potential barrier 105 is not absorbed into FD zone 111 and each transistorized source drain zone of potential barrier is set, so improved sensitivity.
So, because by more transistorized source drain zone directly below potential barrier 105 is set, form and make signal charge more be difficult to the structure that is absorbed by the zone beyond the optical diode, so be more suitable for.
In addition, also potential barrier 105 can be arranged on element separated region 107 below.By potential barrier 105 is arranged on element separated region 107 below, form signal charge and more be difficult to the structure that absorbed by the optical diode in the pixel of adjacency or transistor, can prevent that signal charge from sneaking between the pixel of adjacency.
(the 2nd example)
Fig. 2 is the pattern sectional view of the solid-state image pickup device of the 2nd example of the present invention.
Fig. 2 has optical diode, transmits transistor and makes the pattern sectional view of the solid-state image pickup device of the reset transistor that FD electrode 211 resets, and is provided with to make reset transistor that the FD electrode resets as the 2nd transistor.
In Fig. 2, the 223rd, make resetting that FD electrode 211 resets use transistorized grid, the 224th, make resetting that the FD electrode 211 that is connected with power line 226 resets use the transistor drain zone.
This example is that potential barrier 205 also is arranged on below the 2nd transistorized grid in this example with the difference of example 1.Thereby, because because potential barrier 205 has reduced the signal charge that is absorbed by the zone of the N type semiconductor beyond the optical diode, so improved sensitivity.
In addition, this example is enumerated reset transistor as the 2nd a transistorized example, but can identical the 2nd transistor with the 1st example also can be to amplify or selection reset transistor also.Perhaps also can form a plurality of the 2nd transistors.
For example, also potential barrier 205 of the present invention can be arranged on by optical diode, transmit transistor, reset transistor, amplifier transistor and selection transistor and constitute in the solid-state image pickup device of 1 pixel.
In addition, because when below potential barrier 205 being arranged on whole transistorized grid, source electrode and the drain region that forms in the pixel, make signal charge more be difficult to be absorbed, so improved sensitivity by the zone beyond the optical diode.
And, form by potential barrier 205 is arranged on element separated region 207 below, the potential barrier 205 in zone that will be darker than transistorized source drain zone be arranged on optical diode around solid-state image pickup device.
Because by above like that potential barrier 205 is arranged on optical diode around, make that the signal charge that forms is more difficult to be absorbed by the transistorized source electrode of adjacency or drain region on optical diode, so improved sensitivity.
In addition, for surround optical diode around and in the potential barrier 205 that is provided with, the opening portion more than 1 can be set also.
Potential barrier 205 and signal charge are being set when optical diode overflows around the optical diode when opening portion is not set, the signal charge that overflows from potential barrier 205 is difficult to be absorbed by the N shape semiconductor regions of periphery, causes blooming easily.Therefore, be more preferably, absorb the signal charge that overflows from optical diode, suppress blooming by the opening portion of potential barrier 205 is set at least a portion of optical diode periphery.
(the 3rd example)
Fig. 3 is the pattern sectional view of the solid-state image pickup device of the 3rd example of the present invention.
Fig. 3 has optical diode, transmits transistor and makes the pattern sectional view of the solid-state image pickup device of the reset transistor that FD electrode 311 resets.
In Fig. 3, the 303rd, as the 1st conductive-type semiconductor region in the N type semiconductor zone, the 302nd of the top section of N type trap or N type semiconductor substrate 301, as the P type semiconductor zone, the 312nd of the 2nd conductive-type semiconductor region that constitutes N type semiconductor zone 303 and optical diode, be used for collecting the 1st conductivity type signal charge storage area that is stored in the signal charge that optical diode produces, the zone higher that be impurity concentration than N type semiconductor regional 303.
Fig. 3 and Fig. 2 difference are the transistors that forms the N type source drain zone with opposite conductivity type in Fig. 2 in P type trap 202, are opposite with P type trap 202 same conductivity further with potential barrier 205, in this example, in N type semiconductor zone 303, form the transistor in N type source drain zone, the P type potential barrier 305 with N type semiconductor zone opposite conductivity type further is set with same conductivity as the 1st conductive-type semiconductor region.
In addition, in this example,, exist to be transmitted in the transmission transistor of the signal charge that produces in the optical diode and the reset transistor that the FD electrode is resetted, but transistor is not limited to this as the transistor that constitutes pixel with optical diode.For example, the transistor in the pixel also can be to transmit transistor, reset transistor, amplifier transistor or select in the transistor etc. any one or their combination.
In addition, in this example, hold concurrently and play and prevent to be short-circuited between source drain and the N transistor npn npn also can be worked in N type semiconductor zone 303 effect even if be arranged on potential barrier 305 below the grid of the N transistor npn npn that forms pixel.
In addition, the potential barrier 305 that is arranged on below the grid also can be the potential barrier with size corresponding with area of grid, also can be the potential barrier that forms below grid.
Thereby, in this example, with transmit potential barriers below the transistorized grid 309 be arranged on grid 309 a part below, setting and grid 323 big or small corresponding potential barriers below the grid 323 of reset transistor.
In addition, similarly also can be arranged on potential barrier below the source drain zone described in this specification be arranged on the source drain zone a part below.
In addition, in the such pixel design of Fig. 3 because the direction of advancing for light forms the N type zone of dark optical diode, thus about the quantum efficiency of signal charge than the 1st example height.
In this example, because the N transistor npn npn forms in the N type semiconductor zone in the pixel, so that its threshold potential drops to is lower than the threshold potential of the N transistor npn npn of existing example, so can enlarge the input of amplifier transistor.
In addition, the transistorized threshold potential in this example by making the change that is caused by the reverse grid effect little, can make gain amplifier than existing height.
In addition, also potential barrier 305 can be arranged on element separated region 307 below.By potential barrier 305 is set below element separated region 307, form signal charge and be difficult to the structure that absorbed by the optical diode in the pixel of adjacency or transistor, can prevent that signal charge from sneaking between the pixel of adjacency.
(the 4th example)
Fig. 4 is the pattern sectional view of the solid-state image pickup device of the 4th example of the present invention.
This example and Fig. 3 difference are that potential barrier 405 only is not limited to below transistorized grid in this example, also can be arranged on be present in interior transistorized source electrode of pixel and/or drain region below.
Because have by potential barrier 405 not only only is arranged on grid below, and be arranged on source electrode and/or drain region below, the signal charge that is formed on the generation of potential barrier 405 belows is difficult to by the structure of transistorized source electrode and/or drain region absorption, so can further improve sensitivity.
In addition, in this example,, exist to be transmitted in the transmission transistor of the signal charge that produces in the optical diode and the reset transistor that the FD electrode is resetted, but transistor is not limited to this as the transistor in the pixel.For example, the transistor in the pixel also can be to transmit transistor, reset transistor, amplifier transistor or select in the transistor etc. any one or their combination.
In addition, also potential barrier 405 can be arranged on element separated region 407 below.Because form by potential barrier 405 is set below element separated region 407, signal charge is difficult to be sneaked between the pixel of adjacency so can prevent signal charge by the structure of optical diode in the pixel of adjacency or transistor absorption.
Because as above like that by potential barrier 405 is arranged on optical diode around, the signal charge that forms in optical diode is difficult to be absorbed by the transistorized source electrode of adjacency and/or drain region, so can improve sensitivity with the situation comparison that does not have potential barrier.In addition, also can for surround optical diode around and the opening portion that potential barrier is not set more than 1 is set on the potential barrier 405 that is provided with.
When on the whole faces around the optical diode that opening portion is not set, potential barrier 405 being set and during from optical diode spill over electric charge, because potential barrier 405, the signal charge that overflows is difficult to be absorbed by the N type semiconductor of periphery zone, causes blooming easily.Therefore, absorb, cause blooming easily by N type semiconductor zone at the optical diode periphery.Here,, absorb, can suppress blooming from optical diode spill over electric charge by the opening portion that potential barrier 405 is not set is set at least a portion of optical diode periphery.
In addition, as other form that suppresses blooming, it is lower than the impurity concentration of potential barrier 405 to have the impurity concentration that makes P type semiconductor zone 402, makes the so-called longitudinal type of fleeing from N type semiconductor substrate 401 from optical diode spill over electric charge overflow the drain electrode structure.Because in this structure, opening portion as described above can be set, so compare, can improve sensitivity with the situation that opening portion is not set.
In addition, in this example, also signalization charge storage region 412 not.In addition, also can be N type semiconductor zone at the storage assembly electric charge, perhaps, the interface of signal charge storage area 412 is partly gone up the so-called optical diode of imbedding that forms the P type semiconductor zone.
More than, as the pixel design in the 1st to the 4th example, the polarity of N type, P type is reversed fully.
(the 5th example)
Fig. 5 is the pattern sectional view of the solid-state image pickup device of the 5th example of the present invention.
The sectional view that the 5th example is described as shown in Figure 5.Fig. 5 is identical with Figure 16 of existing example, expresses optical diode part, transmission MOS transistor part and the diffusion part of floating in the pixel.The 501st, N type silicon chip, the 502nd is imbedded P type high concentration layer, the 503rd, and N type epitaxially grown layer, 504a, the 504b that becomes the optical diode negative electrode is that P type separating layer, 505a, 505b are P type trap layers.In addition, 506a is that raceway groove under the field oxide film stops P type layer.The 507th, field oxide film, the 508th, the grid oxidation film of MOS transistor, the 509th, the grid polycrystalline silicon, the 510th of transmission MOS transistor is used to make optical diode to become the surperficial P type layer of baried type.511 is the N type drain diffusion region that transmit MOS transistor again, and the electric charge that temporary transient storage transmits plays a part the floating diffusion region territory.And 512 is the 1st interlayer dielectrics, the 513rd, and contact plug, 514 is that the 1st layer wiring layer, 515 is that the 2nd dielectric film, 516 is that the 2nd layer wiring layer, 517 is that the 3rd interlayer dielectric, 518 is wiring layers, the 519th of the 3rd layer, passivating film.Form 3 layers wiring layer in the present embodiment, but according to the specification of transducer, in order to ensure optical characteristics, make wiring layer be 1 layer or 2 layers also with purport of the present invention contradiction not.In addition, form color-filter layer when using as colored imaging device on passivating film, further form lenticule on the top of colour filter, improve luminous sensitivity, this can similarly carry out with existing imaging device.With the P type high concentration layer of imbedding, surround the N type epitaxial growth zone 503 of the negative electrode that becomes optical diode by P type separating layer 504a, 504b and P type trap layer 505a, 505b, make in abutting connection with electricity between the optical diode of pixel and separate.By incident light 520 that is mapped to pixel and the 521 electron hole centerings that produce, electronics positively is stored in the optical diode as signal charge owing to surround the potential barrier of all P type layer generations of N type epitaxially grown layer.Again P type trap layer 505a also control be positioned at transmit MOS transistor roughly directly below, by the raceway groove that transmits MOS will be stored in the N type epitaxially grown layer 503 be transmitted electronically to the floating diffusion region territory time transfer path.By suitably designing concentration, the degree of depth, the lateral attitude of P type trap layer, when read-out voltage being added on the mos gate utmost point 509, can be in order to make N type epitaxially grown layer 503 exhausting and carry out work fully.Work as the trap that electric charge transmits MOS transistor by the P type trap layer that is electrically connected with P type separating layer 504a, also the threshold voltage of this MOS transistor is controlled.In addition, also P type trap layer 505a is configured in the pixel other transistorized below, work as the trap of these MOS transistor.With the depth design of P type high concentration embedding layer 502 is the degree of depth that can access the dichroism of transducer needs.Except forming potential barrier, preferably make the impurity concentration that becomes peak value at IE15 (/cm
3) more than.Form in order to reduce the most handy high concentration of resistance.Because the ion of high energy high dose injects manufacturing cost is risen, so in fact determined upper limit of concentration.In addition, P type separating layer 504a, 504b consider the aperture area of optical diode and the position that incident light arrives, decision lateral attitude.Impurity concentration is preferably in the IE15 (/cm that can form potential barrier
3) more than.In addition, when the thickness of N type epitaxially grown layer is thicker than present embodiment, further, can be formed in the structure that depth direction is connected with P type layer by appending the 2nd P type separating layer.Below we record and narrate the manufacture method of the structure be used to make present embodiment.The method that forms P type high concentration embedding layer 502 is roughly shown in following 2 methods.In the 1st method, after the surperficial intermediate ion of n type silicon chip 501 injects boron, epitaxial growth n type silicon layer 503.The impurity concentration of n type silicon chip 501 is at IE13～IE15 (/cm
3) scope in be suitable.P type embedding layer 502 can be at IE15～IE20 (/cm again
3) scope in.The impurity concentration in N type epitaxial growth zone 503 can be at IE14～IE16 (/cm
3) scope in.The thickness spectral sensitivity as required in N type epitaxial growth zone 503 is set.If the imaging device of common visible light then is fit to about 2 μ m～6 μ m.In the 2nd method, by from impurity concentration IE14～IE16 (/cm
3) n type silicon chip or n type silicon chip on epitaxially grown substrate surface, with the acceleration energy boron ion implantation of 1MeV～5MeV, form P type high concentration embedding layer 502.Surface one side of P type high concentration embedding layer 502 becomes the N type epitaxially grown layer 503 of Fig. 5.Secondly, inject, form P type separating layer 504a, 504b, then form P type trap layer 505a, 505b by forming wiring pattern and ion.The impurity concentration of P type separating layer 504a, 504b can offset with the N type impurity concentration of the N type silicon of substrate, can clear to P type IE15～IE18 (/cm
3).When the high concentration of impurity concentration that obtains by effective design than N type epitaxially grown layer, when on the PN junction of optical diode, adding reverse blas, can not make exhausting of P type layer yet, can be effective as potential barrier and carry out work.When the thickness of epitaxially grown layer was the 4 μ m left and right sides, P type separating layer 504a, 504b were suitable as stroke 1.5～3.0 μ m that ion injects as present embodiment.In the present embodiment, as the kind boron of ion, with the energy injection 6E11 (cm of 1200KeV
-2) dosage.Stroke according to this condition boron is 1.9 μ m, can carry out P type high concentration and imbed and be electrically connected.P type trap layer 505a, 505b are suitable as stroke 0.5～1.5 μ m that ion injects.In the present embodiment, as the kind boron of ion, with the energy injection 1E12 (cm of 500KeV
-2) dosage.Stroke according to this condition boron is 1.0 μ m, can be electrically connected with P type separating layer 504a, 504b.In addition, when the varied in thickness of epitaxially grown layer, the manufacturing conditions of P type separating layer, P type trap layer changes.For P type trap layer is electrically connected with P type high concentration embedding layer, the thickness of epitaxially grown layer is more than 6 μ m, and it is suitable that P type trap layer constitutes by 2 layers.In addition, the thickness of epitaxially grown layer does not need P type separating layer when 2 μ m are following.The spectral sensitivity of long wavelength's one side of the thickness decision photography element of epitaxially grown layer, if but because be 4 μ m then enough, so the structure of present embodiment is suitable for the photography element of visible region at the thickness of common visible region epitaxially grown layer.Secondly, behind ion injection formation raceway groove barrier layer 506a, 506b, form field oxide film 507 with common LOCOS partition method or リ セ ス LOCOS method etc.After forming polysilicon electrode 509, be infused in formation P type superficial layer 510, N type high concentration layer 511 on the optical diode surface by ion.Because the later manufacture method of contact openings operation is identical with existing photography element, so omit.Also can be captured in the existing optical diode photocarrier of can not portion catching according to present embodiment, improve sensitivity.In addition, the conductivity type that makes epitaxially grown layer in the present embodiment is the N type, but when being the P type by making it, makes other all conductivity type counter-rotatings, also can use the present invention when constituting hole storage type pixel, and this is self-evident.
Fig. 8 is an example of plane graph.In order to surround optical diode 801 P type trap layer and separating layer 802 are configured in the zone of dotted line.The transistorized gate line 803 of transmission that is used to transmit electric charge in the end configuration of optical diode 801.804 is the temporary transient floating diffusion region territories of transmitting electric charge that store again.In this plane graph, do not draw and amplify with MOS transistor, reset and select to use MOS transistor, still in order to realize that the present invention does not add new restriction in the configuration of these elements with MOS transistor or row.The main points on this plane are to surround optical diode by trap layer, separating layer, separate the pixel of adjacency.
Figure 11 is the schematic drawing that the circuit when a plurality of pixel circuit of the present invention of 2 dimension ground configurations constitutes.In 1 pixel 1101, exist optical diode 1102, transmission MOS transistor 1103, amplifying mos transistor 1104, reset mos transistor 1105, select MOS transistor 1106.Connect the grid of colleague's selection MOS transistor mutually with selection wire 1107 respectively, use the grid of reset line 1108 connection reset mos transistors, and connect the grid that transmits MOS transistor,, scan selection with vertical scanning circuit 1110 with conveyer line 1109.Current source 1112 is connected with the output line 1111 of same column, can read the current potential of output line by the work of source electrode tracker.Respectively, transmit MOS transistor 1113 with light signal sense wire 1115 by the light signal of selecting the light signal on the output line is stored in the charge storage part 1118, transmit MOS transistor 1114 with noise signal sense wire 1116 by the noise signal of selecting noise signal is stored in the charge storage part 1118.Read the signal that is stored in the charge storage part 1118 with the horizontal scanning circuit sequential scanning, by unillustrated differential amplifier circuit among the figure, the difference of output light signal and noise signal.
Figure 12 is the figure of the example of the circuit block diagram of expression when will solid-state image pickup device according to the present invention being applied to gamma camera.In photographic lens 1202 fronts are shutters 1201, the control exposure.By aperture 1203 control light quantities, be imaged on the solid camera component 1204 when needing.Handle by signal processing circuit 1205 from the signal of solid camera component 1204 outputs, transform to digital signal from analog signal by the A/D converter.The digital signal of output is further carried out computing in signal processing 1207.Digital signal after handling is stored in the memory 1210, sends to external equipment by exterior I/F1213.Solid-state image pickup device 1204, videotape signal processing circuit 1205, A/D converter 1206, signal processing 1207 and control by regularly producing part 1208, entire system is controlled by integral body control calculating section 1209 in addition.For with picture record in recording medium 1212, by recording medium control I/F part 1211 record output digital signals by the control of integral body control calculating section.
According to the present invention, because except improving significantly the sensitivity of CMOS type solid-state image pickup device, also can constitute the existing big optical diode of N type layer volume ratio, so the saturation current of photography element is increased.In addition, because the impurity concentration of the bonding part of the N type epitaxially grown layer 503 that is connected with the surperficial P type layer 510 of imbedding optical diode is lower than existing, thus can reduce the incidence of picture element defect, thus more also can improve quality with existing example.
(the 6th example)
Fig. 6 is the pattern sectional view of the solid-state image pickup device of the 6th example of the present invention.
The sectional view that the 6th example is described as shown in Figure 6.Because the part of the distribution except grid is identical with the 5th example, so do not draw in the drawings.
With the 5th example difference is to append other N type layer 612 in the structure of optical diode at the near surface of N type epitaxially grown layer 603.This N type layer 612 has below P type superficial layer 610, and in addition, a part enters the structure below the grid 609.It is suitable that the impurity concentration of N type layer 612 is about IE15～IE17 than N type epitaxial growth floor height.Like this because N type layer 612 becomes the low place of electromotive force for electronics, so electronics is collected in the N type layer 612.So, be to be suitable for when transmitting electric charge, transmitting the structure of electronics fully by MOS transistor.Because by transmitting electric charge fully, electron number remaining in optical diode does not wave, so can constitute the little photography element of random noise.N type layer 612 is to inject formation by forming wiring pattern and ion in the operation before forming polysilicon gate 609.Perhaps, use the oblique ion injection method forming polysilicon gate 609 backs, can creep into polysilicon gate 609 below.The other parts of the sectional view of Fig. 6 are identical with the 5th example.Main points of the present invention are that the formation method of P type separating layer 604a, 604b and P type trap layer 605a, 605b can enough methods identical with the 5th example.Because other parts also are identical, so omission is to their explanation.
The effect of present embodiment is by surface one side in the cathode portion of optical diode the impurity concentration part higher than other parts to be set, and transmits electronics in storing with transmitting MOS transistor easily.According to this structure, can realize transmitting fully easily the electric charge of optical diode, the device that random noise is few.In addition, this example constitutes according to the planar configuration shown in Fig. 8,11,12 and circuit and square frame constitutes and also can carry out work effectively as pickup system.
(the 7th example)
Fig. 7 is the pattern sectional view of the solid-state image pickup device of the 7th example of the present invention.
The sectional view that the 7th example is described as shown in Figure 7.
P type separating layer 704a, 704b are illustrated in aspect the impurity concentration fully not the structure that contacts with P type high concentration embedding layer 702 with P type trap layer 705a, 705b in this example.Even if this structure is if these p type island region territories form enough potential barriers and then also can use for the N type zone (N type epitaxially grown layer 703) of optical diode.Potential barrier can be by the charge number decision that will be stored in the optical diode.In addition, the thickness of N type epitaxially grown layer is 2 μ m～6 μ m in the 5th example, but because in P type layer, form potential barrier, so can be increased to a plurality of with separating the number of plies at depth direction.Because the other parts of the sectional view of Fig. 7 are identical with the 5th example, so omission is to their explanation.
If the expression separating layer does not contact with P type embedding layer with P type trap layer in this example, and forms enough potential barriers, then can use the present invention.Represent best according to present embodiment indication and the thickness of N type epitaxially grown layer correspondingly, the separation number of plies and concentration that design needs.
(the 8th example)
Fig. 9 is the pattern sectional view of the solid-state image pickup device of the 8th example of the present invention.
The sectional view that the 8th example is described as shown in Figure 9.
Expression is as the element separation method, with the situation of STI (Shallow TrenchIsolation (shallow ridges separation)) in this example.P type separating layer 904a, 904b are illustrated in the structure that the impurity concentration aspect does not contact with P type high concentration embedding layer 902 with P type trap layer 905a, 905b fully.This structure is identical with the 7th example.Among Fig. 9, there be p type island region territory 906a, the 906b for the exhausting of interface that does not make STI oxide-film 907 and silicon in the bottom of STI oxide-film 907.This p type island region territory is a particular importance for the exhausting of lateral parts that does not make the STI oxide-film.P type trap layer 905a, 905b form the degree of depth identical with the 7th example, prevent that electric charge from piercing in abutting connection with pixel, and the transfer path that transmits MOS transistor is controlled, and also the threshold value that transmits MOS transistor are controlled.In addition, the STI oxide-film 907 P type trap layer 905b below directly element separate directly below form potential barrier, the while also plays a part the following raceway groove barrier layer of STI oxide-film 907.P type separating layer 904a, 904b are identical with other example, imbed between the zone 902 in P type trap layer 905a, 905b and P type high concentration and form potential barrier.
Because other structure is identical with the 6th example to the 7 examples, so omission is to their explanation.
In this example, separate, have with following effect: improved in abutting connection with the separation property between the optical diode by carry out element with STI.So because the surface is the smooth shape of also stablizing the barrier layer with microfabrication.Form P type separating layer and P type trap layer because can enough ions after forming STI inject, so the fine pattern that the thermal diffusion when P type separating layer and P type trap layer can form not because of oxidation broadens.
The photography element that is suitable for making fine pixel with this example of STI.
(the 9th example)
Figure 10 is the pattern sectional view of the solid-state image pickup device of the 9th example of the present invention.
The sectional view that the 9th example is described as shown in figure 10.
Expression separates the situation of (DeepTrench Isolation) method as the element separation method with zanjon in this example.In this example, P type separating layer 1004, P type trap layer 1005 are illustrated in the structure that the impurity concentration aspect does not contact with P type high concentration embedding layer 1002 fully.This structure is identical with the 7th, the 8th example.Ditch separating oxidation film 1007 reaches the degree of depth of 3 μ m in the silicon always, covers the interface in order not make ditch separating oxidation film 1007 and p type island region territory 1006a, the 1006b of the exhausting of interface of silicon.This p type island region territory 1006a, 1006b prevent that dark current from imbedding in the zone 1002 in ditch separating oxidation film 1007 and P type high concentration simultaneously and form potential barrier.
Because other structure is identical with the 6th example to the 8 examples, so omission is to their explanation.
In this example, separate, have following effect by carry out element with the zanjon partition method: and STI has more further improved in abutting connection with the separation property between the optical diode.Because the width of separated region is very little, and can separate, so be the structure that is suitable for fine pixel up to dark zone.
As described above, if according to the present invention, then conduct is by arranging in pixel Potential barrier makes signal charge be difficult to can be realized by the structure that partially absorbs beyond the optical diode Highly sensitive solid-state image pickup device.
And, according to the present invention, because can consist of compared with the prior art the body of N-type layer Long-pending bigger optical diode is so also can make the saturation current of photography element increase. In addition, Because the bonding part of the N-type epitaxially grown layer that is connected with the surperficial P type layer of imbedding optical diode Impurity concentration than low by what have, so can reduce the incidence of picture element defect, thereby with There is example more also can improve quality.
And, impurity concentration is set than other one in surface one side of the cathode portion of optical diode Divide high part, transmit easily the electric charge of optical diode fully, realize the few solid of random noise Imaging device.
Claims (16)
1. solid-state image pickup device, have a plurality of pixels, this pixel comprises that optical diode that the 2nd semiconductor regions by the 1st semiconductor regions of the 1st conductivity type and 2nd conductivity type opposite with the conductivity type of the 1st conductivity type constitutes and described the 2nd semiconductor regions are as source electrode or drain region and bring into play the transistor of the 2nd conductivity type of function, it is characterized in that
Between the above-mentioned optical diode of adjacency, be formed with dielectric film is formed at element separated region in the ditch, be formed with the 3rd semiconductor regions of the 1st conductivity type along the side of said elements separated region, be formed with the 4th semiconductor regions of the 1st conductivity type in the bottom of said elements separated region.
2. solid-state image pickup device according to claim 1 is characterized in that,
Above-mentioned the 4th semiconductor regions is formed by a plurality of ion injecting process on depth direction.
3. solid-state image pickup device according to claim 1 is characterized in that,
Also in above-mentioned the 2nd semiconductor regions of grid bottom, be formed with the 5th semiconductor regions of the 2nd conductivity type.
4. solid-state image pickup device according to claim 3 is characterized in that,
Above-mentioned the 5th semiconductor regions is formed by a plurality of ion injecting process on depth direction.
5. solid-state image pickup device according to claim 1 is characterized in that,
Above-mentioned the 2nd semiconductor regions extends under above-mentioned transistorized grid.
6. a camera system is characterized in that,
Has any 1 described solid-state image pickup device among the claim 1-5.
7. a solid-state image pickup device is characterized in that,
Have a plurality of pixels, be configured in the element separated region between the above-mentioned pixel of adjacency and the semiconductor substrate of above-mentioned the 2nd conductivity type;
Above-mentioned pixel comprises:
Photoelectric conversion department from the 4th semiconductor regions that light inlet side is disposed with the 1st semiconductor regions that is made of the 1st conductivity type, the 2nd semiconductor regions that is made of the 2nd conductivity type opposite with the conductivity type of the 1st conductivity type, impurity concentration constitute than low the 3rd semiconductor regions that is made of the 2nd conductivity type of above-mentioned the 2nd semiconductor regions and by the 1st conductivity type; With
Have the source electrode of the 2nd conductivity type and the transistor of drain region,
This solid-state image pickup device also has the 5th semiconductor regions of the 1st conductivity type that is configured in above-mentioned transistorized grid bottom and is configured in the 6th semiconductor regions of the 1st conductivity type under the said elements separated region;
Surround above-mentioned the 3rd semiconductor regions by above-mentioned the 4th semiconductor regions, above-mentioned the 5th semiconductor regions and above-mentioned the 6th semiconductor regions.
8. solid-state image pickup device according to claim 7 is characterized in that,
Above-mentioned the 5th semiconductor regions is formed by a plurality of ion injecting process on depth direction.
9. solid-state image pickup device according to claim 7 is characterized in that,
Above-mentioned the 6th semiconductor regions is formed by a plurality of ion injecting process on depth direction.
10. solid-state image pickup device according to claim 7 is characterized in that,
Above-mentioned the 2nd semiconductor regions extends under above-mentioned transistorized grid.
11. a camera system is characterized in that,
Has any 1 described solid-state image pickup device among the claim 7-10.
12. a solid-state image pickup device is characterized in that,
Have a plurality of pixels, be configured in the element separated region between the above-mentioned pixel of adjacency and the semiconductor substrate of above-mentioned the 2nd conductivity type;
Above-mentioned pixel comprises:
Photoelectric conversion department from the 4th semiconductor regions that light inlet side is disposed with the 1st semiconductor regions that is made of the 1st conductivity type, the 2nd semiconductor regions that is made of the 2nd conductivity type opposite with the conductivity type of the 1st conductivity type, impurity concentration constitute than low the 3rd semiconductor regions that is made of the 2nd conductivity type of above-mentioned the 2nd semiconductor regions and by the 1st conductivity type; With
Have the source electrode of the 2nd conductivity type and the transistor of drain region,
This solid-state image pickup device also has the 1st potential barrier of the 1st conductivity type that is configured in above-mentioned transistorized grid bottom and is configured in the 2nd potential barrier of the 1st conductivity type under the said elements separated region;
Surround above-mentioned the 3rd semiconductor regions by above-mentioned the 4th semiconductor regions, above-mentioned the 1st potential barrier and above-mentioned the 2nd potential barrier.
13. solid-state image pickup device according to claim 12 is characterized in that,
Above-mentioned the 1st potential barrier is formed by a plurality of ion injecting process on depth direction.
14. solid-state image pickup device according to claim 12 is characterized in that,
Above-mentioned the 2nd potential barrier is formed by a plurality of ion injecting process on depth direction.
15. solid-state image pickup device according to claim 12 is characterized in that,
Above-mentioned the 2nd semiconductor regions extends under above-mentioned transistorized grid.
16. a camera system is characterized in that,
Has any 1 described solid-state image pickup device among the claim 12-15.
Applications Claiming Priority (4)
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| JP187682/2002 | 2002-06-27 | ||
| JP2002187682 | 2002-06-27 | ||
| JP302912/2002 | 2002-10-17 | ||
| JP159403/2003 | 2003-06-04 |
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| CNB031484751A Division CN1266773C (en) | 2002-06-27 | 2003-06-27 | Solid camera device and camera system using same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104681573A (en) * | 2013-11-29 | 2015-06-03 | 索尼公司 | Solid-state imaging element, manufacturing method, and electronic device |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2010206178A (en) | 2009-02-06 | 2010-09-16 | Canon Inc | Photoelectric conversion apparatus, and method of manufacturing photoelectric conversion apparatus |
| JP5538922B2 (en) | 2009-02-06 | 2014-07-02 | キヤノン株式会社 | Method for manufacturing solid-state imaging device |
| JP2010206181A (en) * | 2009-02-06 | 2010-09-16 | Canon Inc | Photoelectric conversion apparatus and imaging system |
| US11114480B2 (en) * | 2013-03-15 | 2021-09-07 | ActLight SA | Photodetector |
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| US20010006237A1 (en) * | 1999-12-27 | 2001-07-05 | Sony Corporation | Solid state image sensor |
| CN1305229A (en) * | 1999-11-15 | 2001-07-25 | 全视技术有限公司 | Optimized floating P+area photoelectric diode for CMOS image sensor |
| US20020175355A1 (en) * | 2001-05-22 | 2002-11-28 | Jin-Seop Shim | CMOS image sensor capable of increasing punch-through voltage and charge integration of photodiode, and method for forming the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN1305229A (en) * | 1999-11-15 | 2001-07-25 | 全视技术有限公司 | Optimized floating P+area photoelectric diode for CMOS image sensor |
| US20010006237A1 (en) * | 1999-12-27 | 2001-07-05 | Sony Corporation | Solid state image sensor |
| US20020175355A1 (en) * | 2001-05-22 | 2002-11-28 | Jin-Seop Shim | CMOS image sensor capable of increasing punch-through voltage and charge integration of photodiode, and method for forming the same |
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| Publication number | Priority date | Publication date | Assignee | Title |
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| CN104681573A (en) * | 2013-11-29 | 2015-06-03 | 索尼公司 | Solid-state imaging element, manufacturing method, and electronic device |
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