CN100573907C - Vertical color filter sensor groups and make used semiconductor integrated circuit manufacture method - Google Patents

Vertical color filter sensor groups and make used semiconductor integrated circuit manufacture method Download PDF

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CN100573907C
CN100573907C CNB2004800427660A CN200480042766A CN100573907C CN 100573907 C CN100573907 C CN 100573907C CN B2004800427660 A CNB2004800427660 A CN B2004800427660A CN 200480042766 A CN200480042766 A CN 200480042766A CN 100573907 C CN100573907 C CN 100573907C
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transducer
sensor groups
layer
sensor
filter
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CN1938856A (en
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R·B·梅里尔
R·A·马丁
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Foveon Inc
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Foveon Inc
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    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14643—Photodiode arrays; MOS imagers
    • H01L27/14645—Colour imagers
    • H01L27/14647—Multicolour imagers having a stacked pixel-element structure, e.g. npn, npnpn or MQW elements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/1462—Coatings
    • H01L27/14621—Colour filter arrangements
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01L—SEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L27/00—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate
    • H01L27/14—Devices consisting of a plurality of semiconductor or other solid-state components formed in or on a common substrate including semiconductor components sensitive to infrared radiation, light, electromagnetic radiation of shorter wavelength or corpuscular radiation and specially adapted either for the conversion of the energy of such radiation into electrical energy or for the control of electrical energy by such radiation
    • H01L27/144—Devices controlled by radiation
    • H01L27/146—Imager structures
    • H01L27/14601—Structural or functional details thereof
    • H01L27/14625—Optical elements or arrangements associated with the device
    • H01L27/14627—Microlenses

Abstract

Go up a kind of vertical color filter sensor groups of formation by the semiconductor integrated circuit manufacturing process at substrate (preferably semiconductor chip), this sensor groups comprises the light sensor of at least two vertical stackings.Others of the present invention are arrays of being constituted of this vertical color filter sensor groups and make this vertical color filter sensor groups and the used method of array.In certain embodiments, sensor groups is to have the solid pieces of material of reading the surface.In this material block, form the transducer of at least two vertical stackings, and at one of transducer with read and construct contact groove (trench contact) between the surface.

Description

Vertical color filter sensor groups and make used semiconductor integrated circuit manufacture method
Technical field
The present invention relates to comprise the photosensitive sensor groups of the transducer of vertical stacking.In each group, semi-conducting material carries out colour filter (perhaps, other material also filters this radiation) to the electromagnetic radiation of vertical incidence, and each transducer detects different wavestrips simultaneously.The present invention also relates to the array of this sensor groups, wherein each sensor groups is positioned different location of pixels.
Background technology
In this article, " filter " and " colour filter " such statement can be exchanged use in a broad sense, to represent a kind of element that at least one wavestrip that incides in the electromagnetic radiation on it is carried out optionally transmission or reflection.For example, one type filter is a dichronic mirror, and it is the radiation in transmission first wavestrip both, reflects the radiation in second wavestrip again.The example of filter comprises the filter that short-pass is crossed, filter and the bandpass filter that long-pass is crossed.
Use term " radiation " to represent electromagnetic radiation herein.
In this article, the such statement of (sensor groups) " top sensor " is meant radiation that transducer that elder generation arrives before arriving any other transducer of this group that incides this sensor groups.The transducer of sensor groups is that " vertical stacking " this statement is meant, one of these transducers are that the top sensor of this group and this group have at least one and pass all the sensors and the axle (being called as " vertical axis " sometimes) that extends.As described below, be used for implementing the transducer that vertical color filter of the present invention (VCF) sensor groups preferably includes vertical stacking, these transducers are configured to make top surface that the top sensor of this group has a definable normal axis (for example, this top surface is flat at least basically), and when this group is incided in the radiation of propagating along the vertical axis of this group, this radiation is to incide (for example, this radiation normal incidence is to this group) on the top sensor less than the incidence angle of 30 degree approximately with respect to this normal axis.
In this article, having two included in the structure of vertical axis unit is that this statement that " laterally " (or " level ") separated is meant, an axle that parallels with vertical axis is arranged, and it extends between two unit but can not intersect with any unit.
(comprise claims) in this article, a product " comprises " that a unit is meant that this product is or comprises this unit.
In the art, the MOS CMOS active pixel sensor is known.In the art, many wavestrips active pixel sensor array also is known.Many wavestrips active pixel sensor array of one type has used ruddiness, green glow and blue sensor, and these transducers flatly place near semiconductor surface or its by a certain pattern.Use colored cover type filter so that be created in color selectivity between ruddiness, green glow and the blue sensor.Such transducer shortcoming is that each resolution cell has occupied relatively large area, because these transducers are tiled in the plane together.In addition, rebuilding coloured image from this sensor array needs very big calculating strength, and usually causes having the relatively poor image of pseudomorphism, defective or resolution.
Many wavestrips pixel sensor array of another kind of type has been used a plurality of sensor groups, and each group comprises the transducer that a plurality of vertical orientations are arranged.The United States Patent (USP) 4 of Carr, 238,760 have announced that a kind of early stage being used to detects an example of the multi-wavelength vertical reference group of visible light and infrared radiation, wherein first diode in the surface n type epitaxial region is in response to visible light, and second diode (being included in the p district that imbeds in the following n type substrate) is in response to infrared radiation.Carr represents, a kind of by using, and " contact diffusion with diffusion type collector electrode under the film common in the bipolar IC treatment process similar and be used to reduce parameters R CS" dark diffusion technology, realize contact to the flush type diode.Carr has also announced an embodiment, and wherein V-type contact groove (see through the technology of carrying out this step of etching in n type epitaxial region and produce this V-type contact groove by comprising) provides the contact in flush type p type district.The device of being announced has the size of 4 square mils.The device of being announced in the patent of Carr has some shortcomings, it should be noted that its area is bigger most, causes it not to be suitable for the density requirements of imageing sensor in the modern imaging system.Be formed into the employed technology of contact of flush type infrared detection diode and be not suitable for modern imaging technique or be not suitable for extending to 3 look transducers.
The United States Patent (USP) 5 of Merrill, 965,875 have announced a kind of three look visible light sensor groups, wherein construct a kind of structure with triple well CMOS technology, and its medium blue, green and the quick PN junction of ruddiness are with respect to the surface (making imager thereon) of semiconductor chip and place the different degree of depth.This three-colour sensor group allows to make intensive imaging array, because these three kinds of colors are detected in as zone roughly the same on the plane.Yet its structure has some shortcomings.At first, this sensor groups has been used the reversed polarity center P N to green light sensitive to tie and has been detected and read green channel, and this requires to improve circuit or voltage range, might also will comprise the PMOS transistor except common nmos pass transistor.This requirement has increased sensor area unfriendly, and makes the support circuits in the detector that comprises these sensor groups complicated.The circuit complexity that is increased makes to be difficult to produce to have the image sensor array of colored readability (as disclosed herein) flexibly, and can not realize the desired very little size sensor of many hyundai electronics imaging applications.
People's such as Cao United States Patent (USP) 6,111,300 have announced a kind of colored CMOS active pixel sensor, it uses PIN photodiode to attempt to collect blue light, also uses two the additional semiconductor junction diode (separating in vertical direction with PIN photodiode) in the semiconductor chip to detect green glow and ruddiness.The shortcoming of this transducer is: difficult and non-type manufacturing technology; Used and do not allowed the very high structure of (in the array) sensor density; Can't select different colors to read; And can't carry out the detection of three kinds or more colors with the monolithic semiconductor substrate.
People such as Findlater (calendar year 2001 IEEE about the seminar of charge coupled device and advanced imageing sensor on K.M.Findlater, D.Renshaw, J.E.D.Hurwitz, R.K.Henderson, T.E.R.Bailey, S.G.Smith, M.D.Purcell and J.M.Raynor delivered paper " A CMOS Image SensorEmploying a Double Junction Photodiode ", IEEE electronic device association (2001)) announced a kind of CMOS active pixel sensor, it covers the binode photodiode and is used in combination with organic filter.Each binode photodiode comprises that n type layer is arranged at top and bottom p type layer and between.This n type layer forms the negative electrode of first photodiode, and bottom p type layer has formed the anode of second photodiode, and first photodiode is coupled to first reading circuit, and second photodiode is coupled to second reading circuit.The chimera covering sensor array of cyan and yellow filter makes in each row of this array, and the transducer of even number receives the radiation of first wavestrip (blue and green) and the transducer of odd number receives the radiation of second wavestrip (red and green).The performance of this sensor array is subject to the relatively poor color response of binode photodiode, and is subject to this fact of negative electrode that n type trap forms these two photodiodes, thereby makes sensor design very easily be subjected to the influence of color interchannel nonlinear crosstalk.In addition, the author has quoted from heterogeneity and the processing/manufacturing limitation that limits this design performance and potential benefit.
The application number of submitting in June 18 calendar year 2001 is that 09/884,863 United States Patent (USP) and above-mentioned application number are in 10/103,304 the United States Patent (USP), to have described some types vertical color filter (" VCF ") sensor groups and manufacture method thereof.The VCF sensor groups comprises at least two light sensors, and they pile up (using or do not use non-sensor material between adjacent transducer) with being perpendicular to one another.Each transducer of VCF sensor groups all has different spectral responses.Typically, each transducer has the spectral response that reaches peak value at the different wave length place.In certain embodiments, VCF sensor groups (perhaps its one or more transducers) comprises the filter that does not serve as transducer.
In the same area of imaging surface, the VCF sensor groups detects the photon of at least two wavestrips simultaneously.On the contrary, sequential photon detection method is not carried out photon detection at synchronization to all wavestrips.(when vertically observing this imager) by imager in the included performed detection of VCF sensor groups occur in the zone of this imager, and, these photons are separated by wavelength according to the degree of depth that arrives in the sensor groups.
Typically; although sensor groups can have " crosstalking " usually when detecting; it is the photon that a plurality of transducers can detect same wavelength; but the photon that each transducer still is used for detecting different wavestrips (for example; a transducer can be than the photon of other sensor to more " blueness " wavestrip; second transducer can be than the photon of other sensor to more " green " wavestrip, and the 3rd transducer can arrive the photon of more " redness " wavestrip than other sensor).
The VCF sensor groups can be used for multiple imaging task.In preferred embodiment, they are used to digital camera (DSC).Yet they also can be used in many other systems, such as linear imager, video camera and machine vision equipment.
The VCF sensor groups uses the attribute of at least a semi-conducting material to detect incident photon, and also detects the incident photon of different wave length on the different depth-selectiveness ground of this group.The detection of different wave length is feasible because the sensor layer of sensor groups be vertical stacking and in semi-conducting material optical absorption depth with wavelength change.The cost of making the VCF sensor groups has reduced much, because the VCF sensor groups does not need outside colour filter (all will use outside colour filter under the regular situation in color image sensor) and do not need the colour filter different with transducer self (transducer self is made by the semi-conducting material that filtering functions can be provided).Yet in some embodiments of the invention, the VCF sensor groups comprises (or therewith using) colour filter different with transducer self really.Compare with the conventional color sensor with non-semiconductor base filter, the spectral response characteristics of VCF color sensor group is usually more stable and more be not subject to influence (these external factor may be present in during the manufacturing or afterwards) such as external factor such as temperature or other environmental factors.
The VCF sensor groups is preferably formed as on substrate (preferably semiconductor chip), and the transducer that comprises a plurality of vertical stackings (for example, sensor layer), by doping and/or biasing these sensor configuration are become to collect the photo-generated carrier (preferably negatron) of first kind of polarity.These transducers comprise one or more datum layers (or a plurality of transducer is to spaced apart by it), and datum layer is configured to collect opposite polarity photo-generated carrier (preferably positive hole) and it is conducted away.These transducers are based on its degree of depth different in sensor groups, also based on comprising other parameters such as doping level and biased condition, thereby have different spectral sensitivities.In operating process, these transducers all are connected to bias voltage and CMOS active pixel sensor reading circuit separately.At application number is that 09/884,863 United States Patent (USP) and application number are in 10/103,304 the United States Patent (USP) in first to file, and VCF sensor groups and manufacture method thereof have been discussed more all sidedly.
As application number be described in 10/103,304 the United States Patent (USP) like that, by on the array of VCF sensor groups, placing a kind of color filter pattern, just can improve to this array.Make and be positioned filter on the subclass of sensor groups by only using by single filter material of planting, the array (by read output signal the different subclass of selecting in the sensor groups of this array) that just can operate each sensor groups has three transducers detects the radiation of four, five or six different wavestrips.This can make color accuracy be improved.The filter of any number of different types can use, this comprise the organic dyestuff filter in some conventional color image sensors and integrate by semiconductor integrated circuit manufacturing process and sensor groups one or more layers filter (for example, absorb one deck polysilicon of short wavelength, alternately pile up the interferometric filter that forms by oxide and nitride layer, or make the another kind of interferometric filter of spectral response setting by interference effect).
Summary of the invention
In a class embodiment, the present invention goes up vertical color filter (VCF) sensor groups that forms by the semiconductor integrated circuit manufacturing process at substrate (preferably semiconductor chip), and this sensor groups comprises the light sensor of at least two vertical stackings.Others of the present invention are the array of this vertical color filter sensor groups and the method for making this vertical color filter sensor groups and array thereof.
In preferred embodiment, the VCF sensor groups is to have the solid pieces of material of reading the surface.Formed the transducer of at least two vertical stackings in this material block, each transducer all has different spectral responses, and these transducers comprise the multi-lager semiconductor material and are configured to biasing to serve as photodiode.This sensor groups is also included within one of transducer and reads contact groove between the surface.
In other preferred embodiment, the VCF sensor groups is a solid pieces of material, and it has upper surface and the lower surface of wanting detected radiation to pass.Formed the transducer of at least two vertical stackings in this material block, each transducer all has different spectral responses, and these transducers comprise the multi-lager semiconductor material, and these transducers are configured to biasing to serve as photodiode.This sensor groups is also included within contact point between one of transducer and the lower surface and at least one and is formed at transistor on the lower surface.Preferably, this transistor is formed on the lower surface by the semiconductor integrated circuit manufacturing process.Bias voltage and reading circuit can be coupled to this transistor.
In other preferred embodiment, the present invention is a kind of method of making the vertical color filter sensor groups on semiconductor chip, and this method comprises the steps: to form first epitaxial loayer; Carry out implant operation so that in first epitaxial loayer, form the first of plug; And after the first that forms plug, on first epitaxial loayer, form second epitaxial loayer, and carry out implant operation so that in second epitaxial loayer, form the second portion of plug.In another kind of embodiment, the present invention is the VCF sensor groups that comprises the plug that forms in this way.Preferably, the material that injects each time all has the diffusivity more much lower than phosphorus.For example, in some embodiment that first epitaxial loayer and second epitaxial loayer mainly are made of p type silicon, the material that is injected is an arsenic.
In other embodiments, the present invention is the array of the VCF sensor groups that forms on semiconductor chip, groove is wherein all arranged between each sensor groups or isolates.
In other embodiments, the VCF sensor groups is formed on the semiconductor chip with first polarity, and comprises the transducer of at least two vertical stackings.Each transducer comprises the carrier collection layer that is made of the semi-conducting material with second polarity (opposite with first polarity), and is configured to collect the photo-generated carrier of second polarity when serving as photodiode when biasing.First sensor comprises the semi-conducting material of first reference body with first polarity, and second transducer comprises the semi-conducting material of second reference body with first polarity.This first reference body and second reference body and are configured to when collecting the photo-generated carrier of first polarity for these transducer biasings when serving as photodiode and they being conducted away between the carrier collection layer of first and second transducers.This sensor groups also comprises the separator of semi-conducting material, and this separator has first polarity and between first reference body and second reference body but mix more than the first and second reference body recuperations.
Another aspect of the present invention is a kind of visual detector, and it comprises that the array of at least one VCF sensor groups and the photo-generated carrier that is used for that transducer is produced are converted to the circuit of the signal of telecommunication.
Description of drawings
Fig. 1 is (with respect to its incident intensity I for the electromagnetic radiation intensity in wavelength 450 nanometers, 550 nanometers and the 650 nanometer silicon metals 0) and the degree of depth in this silicon (unit be micron) between function relation figure.
Fig. 2 is the vertical dopant profile figure that is used for implementing VCF sensor groups of the present invention.
Fig. 2 A is VCF sensor groups with distribution shown in Figure 2 (in vertical plane) cross-sectional view, wherein shows the bias voltage that is coupled to this sensor groups and the schematic circuit of reading circuit.
Fig. 3 is (with respect to its incident intensity I for the absorption of electromagnetic radiation rate in rice (curve C) silicon metal in the rice (curve B) and 650 in the rice (curve A), 550 in the wavelength 450 0) and the degree of depth in this silicon (unit be micron) between function relation figure, its subscript is understood each tectal position of sensor groups shown in Figure 2.
Fig. 4 is its spectral response figure to three photodiodes of similar sensor groups shown in Figure 2 of distributing.
Fig. 5 is the cross-sectional view after embodiment (in the vertical plane) simplification of VCF sensor groups of the present invention.
Fig. 6 is a form, and its (on middle hurdle) is that unit has listed the different In of indium content with the electron-volt xGa 1-xBand-gap energy in the N semiconductor, and (hurdle on the right) listed and the corresponding optical wavelength of each band-gap energy.
Fig. 7 is the cross-sectional view of the snowslide transducer that can comprise in the embodiment of VCF sensor groups of the present invention.
Fig. 8 is the partial cross sectional view of VCF sensor group array of the present invention, and each sensor groups in this array comprises two non-transducer filters and three transducers.
Fig. 8 A is that the part of VCF sensor group array of the present invention is simplified top view, all uses " X " to come mark comprising each group of filter.
Fig. 8 B is that the part of the another kind of array of VCF sensor groups of the present invention is simplified top view, all uses " X " to come mark comprising each group of filter.
Fig. 9 is the partial cross sectional view of VCF sensor group array of the present invention, wherein forms a lenticule on each sensor groups of this array.
Figure 10 is that the part of VCF sensor group array of the present invention is simplified top view, and wherein adjacent sensor groups is shared carrier-collector elements.
Figure 10 A is the cross-sectional view of two VCF sensor groups (in vertical plane) in the array, and wherein two sensor groups are shared a public sensor unit.
Figure 10 B is the top view of four VCF sensor groups in the array, and wherein these four sensor groups are shared carrier-collection areas, and this carrier-collection areas is used to collect the photo-generated carrier that produces by ruddiness and blue photons absorption.
Figure 11 is the partial cross sectional view of conventional sensors array (in vertical plane).
Figure 12 is the partial cross sectional view of the array (in vertical plane) of VCF sensor groups, between the adjacent sensor groups groove isolation construction is arranged in this array.
Figure 13 a-13f is the cross-sectional view of embodiment formed structure (in vertical plane) in each manufacturing step of VCF sensor groups of the present invention.
Figure 14 A-14L is the cross-sectional view of another embodiment formed structure (in vertical plane) in each manufacturing step of VCF sensor groups of the present invention.
Figure 15 A-15H is the cross-sectional view of another embodiment formed structure (in vertical plane) in each manufacturing step of VCF sensor groups of the present invention.
Figure 16 A-16H is the cross-sectional view of formed structure (in vertical plane) in each manufacturing step of another embodiment of VCF sensor groups of the present invention.
Figure 17 is the cross-sectional view of formed structure (in vertical plane) during the embodiment that makes the VCF sensor groups, comprising the plug that forms by injection technology.Each bar outline line (be used to represent between p type and the n section bar material border) shows the result with dissimilar doping levels formation plugs, wherein Zui Xiao n type zone has first (" 1x ") n type doping level, maximum n type zone has the twice (" 2x ") of this doping level, and size n type zone placed in the middle has medium (" 1.4x ") n type doping level.
Figure 18 is the cross-sectional view of formed a kind of structure (in vertical plane) during the preferred embodiment of making VCF sensor groups of the present invention, comprising the bottom (it is formed at the early stage of multistage injection technology) of plug.
Figure 18 A is the cross-sectional view of a kind of structure (in vertical plane) of forming from structure shown in Figure 180 during the preferred embodiment of making VCF sensor groups of the present invention, comprising the top (it is formed at during the next stage of multistage injection technology) of plug, the bottom of this plug all illustrates in Figure 18 and 18A.
Figure 19 shows the desired mask thickness in the typical injection process of boron, phosphorus, arsenic and antimony of mask material shown in five kinds.
Figure 20 is the simplification cross-sectional view of the embodiment (in vertical plane) of VCF sensor groups of the present invention, has wherein comprised between two transducers and has covered barrier layer (205).
Figure 21 is the function relation figure between the degree of depth in doping content and the sensor groups shown in Figure 20.
Figure 22 is the simplification cross-sectional view of the variant (in vertical plane) of sensor groups shown in Figure 20, injects but not the barrier layer 205 of covering of the present invention comprising the barrier layer of covering of routine.
Figure 23 is the function relation figure between the degree of depth in doping content and the sensor groups shown in Figure 22.
Figure 24 is the simplification cross-sectional view of another embodiment (in vertical plane) of VCF sensor groups of the present invention, comprising between two transducers cover barrier layer (205) and (207 and 208) are injected on the other barrier layer of covering.
Figure 25 A-25D is the cross-sectional view that autoregistration replenishes formed structure (in vertical plane) in each step of injection technology during making the embodiment of VCF sensor groups of the present invention.
Embodiment
One of ordinary skill in the art will appreciate that, is illustrative about description of the invention hereinafter, and in office where face is not restrictive.For for the technical staff who benefits the present invention, will be easy to expect other embodiments of the invention.
The most of manufacture process that will describe herein supposes that all transducer made by silicon metal, but this method (or the modification about this method that it will be apparent to those skilled in the art that) also can be applied to the transducer made by other semi-conducting material usually.Each transducer of VCF sensor groups all detects photon by changing the energy of photon into electron hole pair directly or indirectly.This occurs in the semiconductive material.The VCF sensor groups is embodied as usually, makes the output of each transducer in this group represent the different wavestrips of incident radiation.The radiation that arrives each transducer in the VCF sensor groups has different Wavelength strength spectrums because of the material that forms sensor groups has filter action.Therefore, all transducers can be identical in the VCF sensor groups, and each transducer still can produce the output of the different wavestrips of expression.Yet, in certain embodiments, transducer in the VCF sensor groups be not all identical (for example, they are not all to be made of identical materials or combination of materials), and determine the structure of each transducer and component so that make the performance of sensor groups reach best or make moderate progress at predetermined should being used for.For example, wavelength sensitivity to given range higher relatively (promptly absorptance is higher relatively in this scope) and the transducer lower to other wavelength sensitivity, can vertically be stacked with the made transducer of other material with different spectral sensitivities, thereby form the VCF sensor groups.
The colour output of digital camera (DSC) requires three bands of minimum detection because of human visual system's three looks essence.Therefore, many embodiment of VCF sensor groups of the present invention have the transducer (each all comprises semi-conducting material) of three vertical stackings, so that detect three different bands.VCF sensor groups with transducer of two but not three vertical stackings can be used for other occasion, such as being used for visible light and infrared radiation is detected simultaneously, and this is at United States Patent (USP) 4,581,625 and United States Patent (USP) 4,677,289 in describe to some extent.Because it may be favourable detecting more than three SPECTRAL REGION, some embodiment of VCF sensor groups of the present invention have the transducer of more than three vertical stackings.By using extraneous information, just might represent the color of jobbie more accurately from additional SPECTRAL REGION.Because can obtain more spectroscopic data, so the accuracy of color showing is expected to improve.
In a class embodiment of VCF sensor groups of the present invention, each transducer comprise two layers of semi-conductor material (such as, the transducer that has comprises layer X01 and that part of adjacent with X01 of layer X09 among Fig. 2) or the three-layer semiconductor material (such as, the transducer that has comprises layer X02 and layer X09, adjacent with X02 respectively that part of of X10), in transducer, a knot is all arranged (for example between per two adjacent layers, " p-n " knot or heterojunction), and the one deck in these layers of transducer is the carrier-collector elements with contact portion (it can insert bias voltage and reading circuit).In typical operating process, a plurality of layers of each transducer all add bias voltage, make photo-generated carrier pass at least one depletion region and move to this contact portion, thereby can obtain the optical charge signal in this contact site office.In the exemplary embodiments of VCF sensor groups, this group (for example comprises such material, in layer X09 shown in Figure 2, neither belong to the semi-conducting material that depletion region X04 does not belong to depletion region X05 yet), in this material photon can be absorbed and this absorption produce probably can be by the detected electric charge of reading circuit, but photo-generated carrier can be towards any migration (possibility is very big) at least two different carrier-collector elements in this material.Usually, but be not inevitably, layers all in the VCF sensor groups all are made up of semi-conducting material.
Fig. 1 be for wavelength 450 nanometers, 550 nanometers and 650 nanometers in silicon metal electromagnetic radiation intensity (with respect to its incident intensity I 0) and the degree of depth in this silicon between function relation figure.Fig. 3 be for wavelength 450 nanometers (curve A), 550 nanometers (curve B) and 650 nanometers (curve C) the absorption of electromagnetic radiation rate in silicon metal (with respect to its incident intensity I 0) and the degree of depth in this silicon between function relation figure, its subscript is understood the position that has covered each layer of sensor groups thereon shown in Figure 2.Fig. 1 draws from identical data with 3 figure.Each bar curve of Fig. 3 a plurality of differences of having drawn, wherein " n " individual difference is the poor of individual and " n " the individual data value of " (n+1) " of response curve shown in Figure 1.In many semiconductors beyond the silica removal, (having setted wavelength) intensity of radiation and the functional relation of the degree of depth are to shown in Figure 1 very similar.Fig. 1 shows relative intensity (the ratio I/I of (for each wavelength) radiation 0, wherein I is the intensity that the degree of depth in silicon " x " is located, I 0Be incident intensity) reduce with the increase of the degree of depth, because photon has been absorbed by silicon.Fig. 1 and 3 shows with the longer photon of wavelength and compares, there is more relatively blue light (450 nanometer) photon to be absorbed near surface, also show any degree of depth in silicon, green glow (550 nanometer) photon is all many than the blue light photon, and ruddiness (650 nanometer) photon is than green glow photon many (incident intensity of supposition ruddiness, green glow and blue photons equates).
Each bar curve in three curves of Fig. 1 (and Fig. 3) shows that all the increase intensity with the degree of depth is exponential damping, and each bar curve is all based on the behavior that in the silicon metal after classic doping and processing flash ranging is got.The accurate shape of each bar curve will depend on the parameter of mixing and handling, but will have only little difference between each curve that supposition is mixed and/or the processing parameter group is inequality.As everyone knows, semiconductor depends on the details of the band-gap energy and the band edge state of this semi-conducting material to the absorption of the photon of different wave length.Same well-known is that typical semiconductor (for example silicon) has different absorptances to different wavelength.
Can find out obviously that from Fig. 1 and 3 given degree of depth place in the bigger silicon of volume serves as a transducer in the VCF sensor groups and has the silicon of a certain volume of given thickness, to the absorptance of blue light greater than green glow, and to the absorptance of green glow greater than ruddiness.Yet if transducer silicon is sufficiently dark in bigger volume, most of blue light and green glow all will be by this absorbed above transducer silicon.Even having the light of flat basically wavelength-intensity spectrum incides on the surface of larger volume, to arrive the intensity of ruddiness of transducer little a lot of as long as arrive the strength ratio of the green glow of transducer and blue light, transducer in fact also can the absorptance green glow or blue light want many ruddiness.
The exemplary embodiments of VCF sensor groups of the present invention is caught photon by the degree of depth place of different range in the volume of semi-conducting material, realizes the separation of color.Fig. 2 is the vertical dopant profile figure of VCF sensor groups, and it comprises top layer X01 (being made of the n N-type semiconductor N), the layer of second (p type) below top layer X09, the layer of the 3rd (n type) below second layer X02, the layer of the 4th (p type) below the 3rd layer X10, the layer X03 of the 5th (n type) below the 4th layer and the p N-type semiconductor N substrate X11 below layer 5.
Fig. 2 A is the cross-sectional view of this VCF sensor groups (in vertical plane).Shown in Fig. 2 A, bias voltage and reading circuit are coupled to a layer X01, X02, X03, X04 and X05 and substrate X11.
Blue light, green glow and ruddiness photodiode sensor are become by the structure between n type shown in Fig. 2 A and the p type district, and place the following different degree of depth place, surface of this semiconductor structure.Ruddiness, green glow and blue light optical charge signal are all taken from the n type negative electrode (X01, X02 and X03) of the photodiode of three isolation.
The reading circuit of Fig. 2 A is non-storage class, very similar with described in the above-mentioned U.S. Patent application 09/884,863.The reading circuit of each transducer comprises: (54b is used for blue sensor to reset transistor, 54g is used for green sensor, 54r is used for red light sensor), they are driven and are coupling in photodiode cathode and reset potential (in Fig. 2 A with V by the RESET holding wire REFIdentify) between; Source electrode is followed amplifier transistor (one of transistor 56b, 56g and 56r), and its gate coupled is to photodiode cathode and its drain electrode maintains electromotive force V in operating process REFAnd go and select transistor (one of transistor 58b, 58g and 58r), they are driven and are coupling in relevant source electrode by the ROW-SELECT holding wire and follow between the source electrode and line of amplifier transistor.Suffix " r ", " g " are used for representing the wavestrip relevant with each transistor (red, green or blue) with " b ".As is known in the art, the RESET signal be activate so that this pixel is resetted, next be non-activation between exposure period, again after the row route selection be activated so that read detected signal.
In operating process, each among p type district X09, X10 and the X11 all keeps ground potential.Among n type layer X01, X02 and the X03 each all is the carrier-collector elements with contact portion, and this contact portion can be connected to (and can be coupled to) bias voltage and reading circuit.Before the reading each time of sensor groups, bias circuit makes each n type layer reset to reset potential (on ground potential).In the time of in being exposed to the radiation of wanting detected, adjacent p type and the pairing of n type layer just can be served as photodiode through reverse biased: its negative electrode is that layer X01 and anode are first photodiodes of layer X09; Its negative electrode is that layer X02 and anode are second photodiodes of layer X09 and X10; With and negative electrode be that layer X03 and anode are the 3rd photodiodes of layer X10 and X11.As shown in Figure 2, each among n type layer X01, X02 and the X03 all is coupled to bias voltage and reading circuit, thereby has served as the terminals of photodiode.
In typical operating process, when the photodiode reverse biased of Fig. 2, formed the most depletion region that comprises this silicon, photon is absorbed in this depletion region.In Fig. 2, the depletion region of first photodiode (being mainly used to detect blue light) is marked as " X04 ", the depletion region of second photodiode (being mainly used to detect green glow) is marked as " X05 " and " X06 ", and the depletion region of the 3rd photodiode (being mainly used to detect ruddiness) is marked as " X07 " and " X08 ".Electric field in the depletion region separates the electron hole pair that forms by the absorption photon.This has just stayed electric charge the negative electrode of each photodiode, and the reading circuit that is coupled to each negative electrode changes this electric charge into the signal of telecommunication.The electric charge at the negative electrode place of each photodiode is proportional to the number of the photon that this photodiode absorbs.This ratio is quantum efficiency QE.
Fig. 3 shows curve same as shown in Figure 1 (their expression silicon is to the absorption of blue light, green glow and red photons), and also comprises the lines of the scope of the carrier-collector elements (X01, X02 and X03) that is used to represent structure shown in Figure 2 and depletion region.Therefore, be labeled as the above zone of lower surface of depletion region X04 among the region representation Fig. 2 of " X01+X04 " among Fig. 3, be labeled as among the region representation Fig. 2 of " X05+X02+X06 " zone between the lower surface of the upper surface of depletion region X05 and depletion region X06 among Fig. 3, be labeled as among the region representation Fig. 2 of " X07+X03+X08 " zone between the lower surface of the upper surface of depletion region X07 and depletion region X08 among Fig. 3.Therefore, Fig. 3 shows three different " transducer " zones, three photodiodes shown in Figure 2 in these zones, the electric charge that this absorption produced rest on (not move to outside the sensor region that produces electric charge) and can be read out circuit in these zones and record.Yet, should be realized that, the electron hole pair that is produced between three sensor regions (for example, the electron hole pair that is produced among the layer X09 between the upper surface of the lower surface of depletion region X04 and depletion region X05) still can (with very high efficient) be diffused in the sensor region, and on photodiode, produce the electric charge that can record by reading circuit.
By wavelength the selectivity that photon carries out is absorbed the photo response that has determined three photodiodes.If the photon curve of 450 nanometers, 550 nanometers and 650 nanometers is considered the position (" X01+X04 " of sensor region among contact Fig. 3, " X05+X02+X06 ", " X07+X03+X08 "), can see that then the degree of depth of sensor region and scope have determined spectral response.In " X01+X04 " zone, compare with ruddiness with the green glow of incident, there is much more blue incident light to be absorbed, have only a spot of green glow and ruddiness to be absorbed.In " X01+X04 " zone, absorbed green incident light will reduce a lot than blue incident light, and absorbed green incident light is more much more than red incident light.In " X05+X02+X06 " zone, absorbed green incident light (has all been absorbed by this zone because incide the blue light major part in zone " X01+X04 " than blue incident light is many, and arrival regional " X05+X02+X06 "), and absorbed green incident light is than red incident light many (have only seldom to measure by this zone and absorb even incide the ruddiness in zone " X01+X04 ", most of ruddiness can arrive zone " X05+X02+X06 ").
The four corner of incident wavelength (being not only these three wavelength of 450 nanometers, 550 nanometers and 650 nanometers) has determined the spectral response of three photodiodes shown in Figure 2, and this is to shown in Figure 4 very similar.Curve C 1 among Fig. 4 is the spectral response of top (" the blue light ") photodiode similar to top shown in Figure 2 (" blue light ") photodiode, curve C 2 among Fig. 4 is spectral responses of centre (" the green glow ") photodiode similar to centre shown in Figure 2 (" green glow ") photodiode, and the curve C 3 among Fig. 4 is spectral responses of bottom (" the ruddiness ") photodiode similar to bottom shown in Figure 2 (" ruddiness ") photodiode.
In the important embodiment of a class (comprising VCF sensor groups shown in Figure 2), VCF sensor groups of the present invention has realized three photodiodes.This VCF sensor groups can be applicable to DSC or digital camera well.Yet in other embodiments, VCF sensor groups of the present invention has realized two (or more than three) photodiodes, and they are positioned at least mainly the different degree of depth within the volume that is made of semi-conducting material.
Notice that the material that its absorptance changes with wavelength can change the spectral content that passes the radiation that this material propagates according to the degree of depth that enters this material.This material can have multiple function in the VCF sensor groups: they can serve as filter, also can serve as transducer (or unit of transducer).For example, in the embodiment of Fig. 2, each silicon area X01, X02, X03, X09, X10 and X11 had both served as filter, also served as the unit of at least one transducer.In other embodiments, other semiconductor (or layer of at least two kinds of different semiconductive materials) similarly not only serves as transducer (or unit of transducer) but also serves as filter.
In a class embodiment, vertical color filter of the present invention (" VCF ") sensor groups comprises the transducer of vertical stacking, these transducers comprise a top sensor with top surface, detected radiation to incide on the top surface and before other any transducer that arrives this group and propagate into this top sensor by this top surface earlier.This top surface has defined normal axis (and being flat at least substantially usually).Preferably, these transducers are configured to when this group is incided in the radiation of propagating along the vertical axis (above defining) of this group, and this radiation is to incide on this top sensor with respect to the incidence angle of normal axis less than about 30 degree.
Next, with reference to Fig. 5,6 and 7, will the embodiment that semi-conducting material beyond the silica removal (for example, InGaN or other III-V family semi-conducting material, or be not again the semi-conducting material of III-V family material beyond the silica removal) is used to form the VCF sensor groups be described.A kind of neither silicon is not again that the semi-conducting material of III-V family material is a carborundum.Fig. 5 is the simplification cross-sectional view of a kind of VCF sensor groups (in vertical plane), and it comprises top sensor 10, bottom sensor 14 and is positioned intermediate sensor 12 between transducer 10 and 14.Transducer 10 and 12 is all by In xGa 1-xThe N semi-conducting material is formed, wherein for transducer 10, and x=0.475, and for transducer 12, x=0.825.Transducer 14 is made up of silicon basically.Usually, transducer 10 and 12 is all by multilayer In xGa 1-xThe N semiconductor is formed, they have determined to be coupled with bias voltage to serve as at least one knot of photodiode in operating process, and transducer 14 (for example is made up of the silicon that multilayer has different doping, one deck n type silicon and this above n type layer and below the adjacent p type silicon layer part of difference), they are coupled with bias voltage to serve as photodiode in operating process.
Use mainly the transistor of forming by one or more III-V family semi-conducting materials and determine in operating process, to be coupled with bias voltage and all fall within the scope of the present invention with the knot ways such as (knot of any kind comprise heterojunction or Schottky barrier layer) of serving as photodiode.
Fig. 6 is a form, and its (in one hurdle, centre that indicates " energy gap ") is that unit has listed the wherein different In of indium content with the electron-volt xGa 1-xThe band-gap energy of N semiconductor (the value difference of subscript " x ").Fig. 6 also (on the right in the hurdle) has listed and the corresponding optical wavelength of each band-gap energy.Therefore, Fig. 6 points out, by In 0.1Ga 0.9The absorbent maximum wavelength of transducer that the N semiconductor is made is 388 nanometers, and transducer 10 shown in Figure 5 is (by In 0.475Ga 0.525The N semiconductor is made) absorbent maximum wavelength is about 500 nanometers, and transducer 12 shown in Figure 5 is (by In 0.825Ga 0.175The N semiconductor is made) absorbent maximum wavelength is about 612 nanometers.
Therefore, transducer 10 makes all transmissive of all (or all basically) green glows that incide on it and ruddiness, and preferably has enough thickness and make it can sponge all (or all basically) blue lights that incide on the sensor groups shown in Figure 5.Similar is, transducer 12 makes all transmissive of all (or all basically) ruddiness of inciding on it, and preferably has enough thickness and make it can sponge all (or all basically) green glows that incide on the sensor groups shown in Figure 5.Transducer 14 preferably has enough thickness makes it can sponge all (or most at least) ruddiness that incide on it.
Usually, when using In xGa 1-xN semi-conducting material (or other III-V family semi-conducting material) is when forming the VCF sensor groups, selects the parameter of this material (such as, In at each transducer of VCF sensor groups xGa 1-xParameter among the N " x ") to realize the band-gap energy (for example, make a transducer to the optical transparency of wavelength greater than threshold value, wherein this threshold value is determined by band-gap energy) of expectation.
More common situation is, in preferred embodiments more of the present invention, at least also have a kind of semi-conducting material to be used to realize at least one transducer of VCF sensor groups beyond the silica removal, and select this material can make transducers different in this group optionally to different wavestrip sensitivities.In some such preferred embodiments, used at least two kinds of dissimilar semi-conducting materials to realize each transducer in the VCF sensor groups, and select material so that in should group different transducer optionally to different wavestrip sensitivities.
Some embodiment of VCF sensor groups of the present invention comprise at least one " snowslide " photodiode, and this photodiode just can be collected a more than electronics because of " snowslide " gain process realizes photon of every absorption.In the avalanche gain process, first electron hole pair that absorption by photon produces has produced at least one additional electron hole pair, and the prerequisite hypothesis is the band-gap energy that the energy of this first electron hole centering electronics has surpassed the semi-conducting material that is used to form photodiode sensor.Semi-conducting material has electronic ionization coefficient (a n) and hole ionization coefficient (a p), 1/a wherein nBe to produce the average distance of being advanced before the new electron hole pair, 1/a because of ionization by collision after electronics is accelerated in material pBe to produce the average distance of being advanced before the new electron hole pair because of ionization by collision after the hole is accelerated in material.Compare a with ionization coefficient in the semi-conducting material that forms photodiode p/ a nMuch larger than 1 or compare much smaller than 1 situation, ionization coefficient compares a in the semi-conducting material that is forming photodiode p/ a n, realize that practical avalanche photodide will become very difficult at 1 o'clock no better than.
In some embodiments of the invention, at least one transducer of VCF sensor groups is the snowslide transducer, and it comprises photo-absorption region and the avalanche region that separates with this photo-absorption region.For example, Fig. 7 is the cross-sectional view that can be included in the such snowslide transducer in the VCF sensor groups.The transducer of Fig. 7 comprises: substrate 20 (being made by n+ type silicon); Layer 21 (making) on the substrate 20 by n-type silicon; Layer 22 on the layer 21 is (by the relatively low n type In of doping content xGa 1-xThe N semi-conducting material is made); And the layer 23 on the layer 22 is (by the higher relatively p type In of doping content xGa 1-xThe N semi-conducting material is made).Metallic contact 27 is formed on the layer 23, and substrate 20 is coupled to metallic contact 25 by the vertical orientation contact area that is made of n+ type silicon.In operating process, biasing between metallic contact 25 and 27, reading circuit can be coupled to contact 27.Isolation is to be provided by (and between substrate 20 and the material 27A) dielectric substance 24 (can be silicon nitride) between the dielectric substance 27A (it can be made of photoresist, for example poly-polydimethyl glutarimide protective layer) around layer 21,22 and 23 and layer 21,22,23 and the dielectric substance 27A.
In operating process, layer 22 and 23 serves as photo-absorption region, wherein forms electron hole pair in response to the photon of incident.Be used to form the In of layer 22 and 23 xGa 1-xThe N semi-conducting material has ionization coefficient much larger than (or much smaller than) 1 than (a p/ a n), therefore layer 22 and 23 is not used to the avalanche gain zone.
In operating process, layer 21 and 20 serves as the avalanche gain zone, has wherein formed new electron hole pair in response to formed electron hole pair in the photo-absorption region.Compare with the ionization coefficient ratio of layer 22,23, be used to form layer 21 and 20 silicon and have more near 1 ionization coefficient than (a p/ a n).
Usually, some embodiment of VCF sensor groups of the present invention comprise at least one transducer as avalanche photodide, wherein this avalanche photodide comprises: photo-absorption region, (for example, InGaN) ionization coefficient of middle electronics and the ionization coefficient in hole differ greatly constituting this regional semi-conducting material; And the avalanche region that separates with photo-absorption region, the ionization coefficient in electronics and hole is almost equal in the another kind of semi-conducting material (for example, silicon) that constitutes this zone.Can expect, a kind of important purposes of the transducer of realizing as avalanche photodide is to detect low intensive radiation, such as, before arriving avalanche photodide, significantly reduce the radiation of (for example by absorbing) by its intensity between other transducer propagation periods of at least one filter and/or at least one.
In other embodiment of VCF sensor groups of the present invention, at least one filter that does not serve as transducer (or sensor unit) is stacked with the semi-conducting material of one deck at least that serves as transducer (or sensor unit or one or more transducer).This filter can but do not need to have with embodiment illustrated in fig. 2 in the sensitivity of silicon identical spectra.
Filter is generally removed wavelength from radiation on following meaning.For each filter, first and second wavelength are all arranged, if make this first and second wavelength respectively with intensity " I1 " with " I2 " incides on the filter and the intensity in transmission of first and second wavelength (after by the filter transmission) is respectively " O1 " and " O2 ", O1≤I1 then, O2≤I2, and O1/02＜I1/I2.
One type included filter is " conversion filter " (for example " conversion layer ") among some embodiment of VCF sensor groups of the present invention, and it can change the wavelength that incides the electromagnetic radiation on it." conversion " filter absorbs a kind of photon of wavelength, and sends the shorter or longer photon of at least a wavelength.Usually, the material that comprises conversion filter is a nonlinear optical material.The photon conversion that conversion filter can be used for frequency is lower than the transducer cut-off frequency is higher frequency, and they just can be detected like this.Perhaps, conversion filter can be used for the photon conversion of frequency on threshold frequency arrived lower frequency, and they just can be detected like this.The latter's a example is an x-ray conversion layer, and the X ray that is used for penetrating most of test material easily is converted to easily detected visible light.In some embodiments of the invention, thickness is about the cesium iodide layer that is mixed with thallium that 100 microns oxygen gadolinium sulfide layer or thickness is about 100 microns to 600 microns and can be used as this x-ray conversion layer.
Have two kinds of relevant modes to detect one group of photon in the band, and each mode may be used to realize the present invention.In some embodiment of VCF sensor groups of the present invention, at least one filter is removed the photon beyond at least one wavestrip, and the remaining photon of the sensor of at least two vertical stackings, wherein each transducer all is the element that separates with each filter.Other embodiment of VCF sensor groups of the present invention does not comprise non-transducer filter (promptly not being the filter of transducer), but comprises the transducer to limited wavestrip sensitivity really.Other embodiments of the invention can be by comprising first sensor and second transducer below first sensor, realize the combination of these methods, wherein first sensor has absorbed narrow wavelength and has made this scope photon in addition be transmitted to second transducer, and this second transducer is quick to all wavelength Turin.In this example, first sensor serves as the filter of second transducer.
In some embodiments of the invention, at least one non-transducer filter is positioned between the transducer of at least one pair of vertical stacking in the VCF sensor groups, maybe on the top sensor that should organize, maybe under the bottom sensor that should organize.When this filter is positioned between the transducer of a pair of vertical stacking in the VCF sensor groups, this filter can be any in the number of different types, and this comprises (but be not limited to following these): filter can absorb radiation and other wavelength of transmission the and radiation of any wavelength is not caused too many reflection simultaneously in the wavestrip; Filter can reflect radiation and other wavelength of transmission and simultaneously the radiation of any wavelength is not caused too many absorption in the wavestrip; Or filter can be to the radiation height transmission in the wavestrip, the radiation height in another wavestrip is absorbed, and the radiation in the 3rd wavestrip is caused high reflection.The VCF sensor groups of Fig. 8 comprises after two one type non-transducer filter: colour filter 43 and colour filter 48.Should be appreciated that sensor groups shown in Figure 8 is an example among the present invention many embodiment that can estimate.
Fig. 8 is the partial cross section figure of an embodiment (in vertical plane) of VCF sensor group array of the present invention, and it comprises two non-transducer filters (layer 43 and 48) and four insulating barriers (diffusion impervious layer 42,44,47 and 48).Each insulating barrier can be made of silicon dioxide.In Fig. 8, a VCF sensor groups comprises: the layer 51 (making) by the n N-type semiconductor N and on layer 51 with below p N-type semiconductor N material layer 50; Insulating barrier 49 below material 50; Colour filter 48 below layer 49; Insulating barrier 47 below filter 48; The layer 46 (making) by the n N-type semiconductor N and on layer 46 with below p N-type semiconductor N material layer 45; Insulating barrier 44 below material 45; Colour filter 43 below layer 44; Insulating barrier 42 below filter 43; The layer 41 (making) by the n N-type semiconductor N and on layer 41 with below p N-type semiconductor N substrate material 40.The plug of perpendicular positioning all is connected to the top surface of sensor groups with layer 41,46 and 51, and each layer 41,46 and 51 can be coupled to bias voltage and reading circuit like this.Shadow shield 54 is installed in above the plug and weakens frequency selectivity to prevent radiation (normal incidence is to the radiation of sensor groups top surface) from arriving plug.The array of Fig. 8 also comprises the 2nd VCF sensor groups, and it comprises: the layer 63 (making) by the n N-type semiconductor N and on layer 63 with below p N-type semiconductor N material layer 50; Insulating barrier 49 below material 50; Colour filter 48 below layer 49; Insulating barrier 47 below filter 48; The layer 62 (making) by the n N-type semiconductor N and on layer 62 with below p N-type semiconductor N material layer 45; Insulating barrier 44 below material 45; Colour filter 43 below layer 44; Insulating barrier 42 below filter 43; The layer 61 (making) by the n N-type semiconductor N and on layer 61 with below p N-type semiconductor N substrate material 40.The plug of perpendicular positioning all is connected to the top surface of sensor groups with layer 61,62 and 63, and each layer 61,62 and 63 can be coupled to bias voltage and reading circuit like this.Shadow shield 53 is installed in above the plug of the 2nd VCF sensor groups to prevent that radiation (normal incidence is to the radiation of sensor groups top surface) from arriving plug.
In variant embodiment illustrated in fig. 8, n type layer 51 and 63 horizontal orientation variant (they lack the contact portion of vertical orientation) are exposed to the top surface (and not covered by semi-conducting material 50) of sensor groups.Each n type layer that exposes like this can be directly connected to (for example, by Metal Contact formed thereon) bias voltage and reading circuit.Similar is, in variant embodiment illustrated in fig. 8, n type layer 46 and 62 directly places layer 47 following (no longer with p N-type semiconductor N material 45 it being separated with layer 47), and n type layer 41 and 61 directly places layer 42 following (no longer with p N-type semiconductor N material 40 they being separated with layer 42).
In operating process, make each layer p type semiconductor layer among Fig. 8 all keep ground potential.By the plug that can insert (maybe can be coupled to) bias voltage and reading circuit each layer n type layer all is coupled together.Before the reading each time of each sensor groups, bias circuit resets to reference potential (on ground potential) with each layer n type layer.Be exposed between the radiation era that will detect, p type and n type layer pairing back reverse biased adjacent in the first sensor group just can be served as photodiode: first photodiode, its negative electrode is a layer 51, its anode is adjacent material layer 50 (being called as " blue light " transducer, because it has absorbed the blue photons of Duoing than green glow or red photons in response to the white light that incides this sensor groups top); Second photodiode, its negative electrode are layers 46, and its anode is adjacent material layer 45 (being called as " green glow " transducer, because it has absorbed the green glow photon of Duoing than blue light or red photons when white light incides this sensor groups top); And the 3rd photodiode, its negative electrode is a layer 41, its anode is adjacent material layer 40 (being called as " ruddiness " transducer, because it has absorbed the red photons of Duoing than blue light or green glow photon when white light incides this sensor groups top).Be exposed between the radiation era that will detect, p type and n type layer pairing back reverse biased adjacent in second sensor groups just can be served as photodiode: first photodiode, its negative electrode is a layer 63, its anode is adjacent material layer 50 (being called as " blue light " transducer, because it has absorbed the blue photons of Duoing than green glow or red photons in response to the white light that incides this second sensor groups top); Second photodiode, its negative electrode are layers 62, and its anode is adjacent material layer 45 (being called as " green glow " transducer, because it has absorbed the green glow photon of Duoing than blue light or red photons when white light incides this second sensor groups top); And the 3rd photodiode, its negative electrode is a layer 61, its anode is adjacent material layer 40 (being called as " ruddiness " transducer, because it has absorbed the red photons of Duoing than blue light or green glow photon when white light incides this second sensor groups top).
When layer 40,41,45,46,50 and 51 is made by silicon metal (all being so usually), layer 51 and 50 is preferably thin and layer 41 and 40 is thinner than layer 51 and 50 respectively than layer 46 and 45 respectively, the difference of thickness want strength ratio that sufficient to guarantee incides the green glow of each green sensor and ruddiness enough high, guarantee that simultaneously the ruddiness more much more than green glow incides on each red light sensor and the blue light more much more than green glow absorbed by each blue sensor.Usually, layer 51 and 50 (and in second sensor groups layer 63 and a 50) combination thickness in the first sensor group is 0.3 micron or still less, and the layer 45 and 46 in the first sensor group (and the layer 45 and 62 in second a sensor groups) combination thickness is about 0.5 micron.
Colour filter 43 is " ruddiness by/reflection of blue or green light " filters, and it is to the transmission of ruddiness height but reflect most of or most blue light and green glow incident thereon.Colour filter 48 is " gold-tinted by/blu-ray reflection " filters, and it is to ruddiness incident thereon and the transmission of green glow height, but reflects most of or most blue light incident thereon.Other embodiments of the invention are used the transmission filter of non-reflection-type.
The effect of filter 43 is to increase the ruddiness that absorbed by each red light sensor and the ratio (and ratio of ruddiness and blue light) of green glow, and can reduce or eliminate if save red/Green Zone branch problem that 43 of filters may influence red light sensor.Similar is, the effect of filter 48 is to increase the green glow that absorbed by each green sensor and the ratio of blue light, and can reduce or eliminate if save green/blue area branch problem that 48 of filters may influence green sensor.
The effect of filter 48 also is to increase the blue light that absorbed by each blue sensor and the ratio of green glow (and ruddiness), because have another time chance to be absorbed by blue sensor from the blue light of filter 48 reflections.The blue light absorption of each blue sensor all is improved, and does not increase simultaneously its response to ruddiness and green glow, because how much ruddiness and green glow be not from filter 48 reflected back blue sensor.Similar is, the effect of filter 43 also is to increase the green glow that absorbed by each green sensor and the ratio of ruddiness, because have another time chance to be absorbed by green sensor from the green glow of filter 43 reflections.The green glow of each green sensor absorbs and all increases, and does not increase its response to ruddiness simultaneously, because how much ruddiness is not from filter 43 reflected back green sensor.Considerably less blue light arrives green sensor, because nearly all blue light or absorbed by blue sensor, or has been reflected back towards blue sensor by filter 48.
There is the various material of kind can serve as filter in the VCF sensor groups (for example, the filter 43 or 48 among Fig. 8, or reflect a wavestrip and, or absorb a wavestrip but and unreflecting filter) to the filter of the equal transmission of all other wavelength.These materials can be used in combination or have all thickness.Determine by their optical characteristics on these configuration section degree, but depend primarily on the integrated factor of processing.
Photon can be reflected in interface between material and the material.When the reflectivity of mirror had selectivity by wavelength, this mirror (no matter be between material or the material interface) can serve as the filter in the VCF sensor groups of the present invention.For example, some embodiment of VCF sensor groups of the present invention comprise dichronic mirror, the radiation in its transmission first wavestrip and reflect radiation in second wavestrip.
As mentioned above, the stack layer made of the material that is changed with wavelength by light absorption can be used as the filter among each embodiment of VCF sensor groups of the present invention.In the preferred embodiment that comprises different doped semiconductor materials (for example silicon) layer, one semiconductor layer is used as filter and transducer simultaneously at least.At the layer of semiconductor material by in the VCF sensor groups as the negative electrode (or anode) of filter and photodiode sensor simultaneously, can be added in the anode of photodiode and the bias voltage between the negative electrode by control, also can suitably control the spectral sensitivity of this transducer by the doped level of definite foreign atom and the spacing structure of position and sensor unit.
The filter that is included in the another kind of type in the some embodiments of the present invention is a thin metal film.Thin metal film can serve as the partial reflection device, can filter the photon of incident thus.The photon that is reflected returns by each layer above them, and this has given their absorbed chances for the second time.
The filter of other included type is in the some embodiments of the present invention: interferometric filter (for example, having the stack layer of the dielectric substance of differing dielectric constant), and it reflects some wavelength and other wavelength is passed through; And organic and inorganic dyestuff and pigment.
In some embodiments of the invention, filter with any pattern distribution in the VCF of array sensor groups, for example, as application number be described in 10/103,304 the patent like that.These filters can but do not need identical all.Preferably, one of each filter and VCF sensor groups form one (for example, as a layer that is formed on the semiconductor layer or between the semiconductor layer).Perhaps, filter and sensor groups can be made separately, filter are positioned to engage on this sensor group array and with the VCF sensor groups then (or be attached to or be fixed to respect to the VCF sensor groups place, a fixed position).Filter can be provided with by " replacing " mode shown in Fig. 8 A or " chessboard " mode, wherein indicate each square expression VCF sensor groups of " RGB ", and indicate each square VCF sensor groups of representing to comprise a filter of " X ".Shown in Fig. 8 A, each odd number sensor groups in the row of each odd number comprises a filter, each even number sensor groups in each even number row comprises a filter, thus in the color sensor group with filter with do not have between the color sensor group of filter and obtained best spatial frequency.
Perhaps, filter can be provided with by the pattern shown in Fig. 8 B, wherein indicates each square expression VCF sensor groups of " RGB ", and each the square expression that indicates " X " comprises the VCF sensor groups of a filter.When filter is provided with by pattern shown in Fig. 8 B, allow completely to estimate colour simultaneously and read the mode that emulation is read with mosaic and distribute filter by a kind of, guarantee that simultaneously two types image is read each combination that comprises output of color sensor group and colour filter.Perhaps, can distribute filter in the sensor groups of VCF sensor group array by any other pattern, wherein some is to describe to some extent in 10/103,304 the patent at application number.
Some embodiment of VCF sensor groups of the present invention comprise that at least one lens is to substitute at least one filter or replenishing as this at least one filter.For example, in the VCF sensor group array, can on each (or just) VCF sensor groups, form lenticule.Sometimes when metallization (or another kind of structure) has limited the pore size (incident radiation will propagate into the area at least one transducer in imaging plane) of VCF sensor groups, photoresist can deposit on this aperture, develop then, the photoresist material melts becomes recessed or convex like this, thereby has formed lenticule.According to the properties of materials and the lens shape that constitute lens, lens are except can serving as filter as the lens.For example, Fig. 9 is the partial cross sectional view of the variant (in vertical plane) of VCF sensor group array shown in Figure 8.Array shown in Figure 9 comprises a VCF sensor groups, and a VCF sensor groups further comprises: n type semiconductor layer 51,46 and 41, and they all are formed among the p N-type semiconductor N material; The contact of vertical orientation is used for each layer 41,46 and 51 is connected to the top surface of sensor groups; And shadow shield 54, it is installed in above the contact to prevent that radiation (radiation of normal incidence to the top surface of sensor groups) from arriving contact.Array shown in Figure 9 also comprises the 2nd VCF sensor groups, and the 2nd VCF sensor groups further comprises: n type semiconductor layer 61,62 and 63, and they all are formed among the p N-type semiconductor N material; The contact of vertical orientation is used for each layer 61,62 and 63 is connected to the top surface of sensor groups; And shadow shield 53, it is installed in above the contact to prevent that radiation (radiation of normal incidence to the top surface of sensor groups) from arriving contact.Shadow shield 53 and 54 is formed in the layer 64, and 64 pairs of radiation that will detect of layer are transparent.Shadow shield 53 and 54 apertures, and shadow shield 53 and the aperture of another shadow shield (not shown) round second sensor groups round the first sensor group.Protruding lenticule 65 is formed on the layer 64 above first group the aperture, and protruding lenticule 66 is formed on the layer 64 above second group the aperture.
When lenticule is distributed in the sensor groups of VCF sensor group array by alternating pattern (pattern shown in Fig. 8 A), can select in the sensor groups radiation to be had each subclass of different sensitivity separately.This provides the dynamic range of expansion for making as a whole array.
The aperture of each sensor groups normally square or octagon in the VCF sensor group array, but also can have other shape (for example, rectangle, circle or irregularly shaped).Formed lenticule is normally foursquare on the aperture of whole or some sensor groups of this array, but also can have other shape.
Some embodiment of VCF sensor groups of the present invention comprise at least one lenticule as compound lens (for example, recessed lenticule and protruding lenticular combination).
As everyone knows, form lenticule and with the top layer as the ccd image sensor array, wherein on each transducer of array a lenticule is arranged.Simultaneously know that also the lenticule that comprises can be used as the intermediate layer of ccd image sensor array, for example, the lenticule of two vertical separation is arranged on each transducer of array, and between this lenticule, colour filter is arranged vertical separation.In some embodiments of the invention, lenticule (for example, the lenticule 65 of Fig. 9) with respect to the transducer of VCF sensor groups and locate, so that the top sensor that radiation is refracted to this group (for example, that transducer that comprises layer 51 among Fig. 9) in, make at least some radiation pass to each transducer that is positioned at below this top sensor by top sensor, the prerequisite hypothesis is that this radiation is included in it and can arrives before the bottom sensor neither by this group absorption again not by at least one wavelength that element reflected of this group.
In exemplary embodiments of the present invention, expect very much (for other purpose) used material in the semiconductor machining processing procedure is used to realize filter, lens and transducer, because they can be added in the VCF sensor groups under the situation of not revising technology.The example of this material is polysilicon, silicon dioxide and silicon nitride.Polysilicon layer can be used as filter, and its absorption spectrum depends on the thickness of its crystallization property and conductivity and this layer and with respect to the degree of depth of other unit of VCF sensor groups.Silicon oxide layer that (for example, silicon face) upward grows on a certain surface and two nitrogenize silicon layers can form the interferometric filter in the VCF sensor groups.
In this article, implement in the VCF sensor groups of the present invention being used for, a kind of like this statement of " the size minimum " carrier-collector elements is meant, its with the perpendicular plane of the defined normal axis of the upper surface of this group top sensor on the area of institute's projection be not more than that carrier-collector elements that this organizes other carrier-collector elements area of institute's projection on this plane.In this article, (one group) " minimum collect area " be meant, in this group the carrier-collector elements of size minimum with the perpendicular plane of the defined normal axis of upper surface of this group top sensor on the area of institute's projection.In a class embodiment of sensor groups of the present invention, as shown in the sensor groups of Figure 10,10A and 10B, compare with the carrier-collector elements of each size minimum in this group, in this group the carrier-collector elements of some transducers have basically bigger " size " (with the perpendicular plane of the normal axis of the upper surface of this group top sensor on the area of projection).In this class preferred embodiment, some carrier-collector elements of sensor groups have the size that doubles the minimum collection of this group area at least.This carrier-collector elements is shared by at least one other sensor groups institute in the array usually, and its size is substantially equal to shared its size summation of all groups usually at least.
The array of Figure 10 comprises a plurality of sensor groups, and wherein six are illustrated among Figure 10.Each sensor groups comprises a green sensor (its carrier-collection areas is not shared with any other sensor groups), blue sensor (shared with other a sensor groups) and red light sensor (shared with other a sensor groups).The carrier-collection areas of each red light sensor and blue sensor is all shared by two sensor groups.The carrier-collection areas that is used for blue light and red photons is greater than the collecting zone that is used for the green glow photon.
In the variant of array shown in Figure 10 or the 10B, at least one carrier-collection areas (shared by two sensor groups) comprises two or more parts, lateral separation each other when these parts form at first forms their short circuits single effective carrier-collection areas then together.For example, each blue sensor can comprise the carrier-collection areas that is used for blue photons of two lateral separation, each zone is formed on the different carrier-collection areas of green glow photon, these two the carrier-collection areas lateral separation that are used for blue photons form at least one transistorized space so that provide on the array upper surface of between.The carrier-collection areas of two lateral separation of each blue sensor by short circuit together, form the single carrier-collection areas that effectively is used for blue photons, its overall size than in the array each to be used for the carrier-collection areas of green glow photon all big.
With reference to Figure 10, electric charge collected on each red light sensor is converted into the signal of telecommunication, and this signal of telecommunication is represented the twice of the mean value of the red light intensity of institute's incident on two sensor groups of shared this red light sensor.Electric charge collected on each blue sensor is converted into the signal of telecommunication, and this signal of telecommunication is represented the twice of the mean value of the blue light strength of institute's incident on two sensor groups of shared this blue sensor.Like this, the resolution of the relevant green glow of this array is the twice of the resolution of relevant ruddiness or blue light.Such array has increased the signal to noise ratio in blue light and the ruddiness channel, has also kept the high spatial resolution in green glow (or image brightness the is such) channel simultaneously.High brightness resolution is achieved, because each location of pixels all has effective green sensor, by contrast, uses the normal image sensor array of Bayer pattern only to have green sensor in the pixel position of half.Those skilled in the art should be able to recognize, keeps high brightness resolution to make by sample rate higher in the green glow channel and adopts the pseudomorphism that exists in the interpolated image that this array produced to reduce to some extent.Bigger blue light and ruddiness carrier-collection areas can further reduce the existence of pseudomorphism.
In other embodiments, in the VCF sensor group array carrier-collection areas of blue sensor less than the ruddiness of this array and the carrier-collection areas of green sensor.
In some embodiment of VCF sensor group array, sensor groups comprises at least one and the shared transducer (or unit of transducer) of another sensor groups.Figure 10 A is the cross-sectional view of this array (in vertical plane).In Figure 10 A, the first sensor group comprises: first sensor, this first sensor self comprise layer 102 (being made by the n N-type semiconductor N) again and near above the layer 102 and following p section bar material zones 100; And second transducer, this second transducer self comprises layer 101 (being made by the n N-type semiconductor N) again and near above the layer 101 and following p section bar material zones 100.Figure 10 A also shows second sensor groups, and it comprises: the 3rd transducer (the 3rd transducer comprise layer 103 that the n N-type semiconductor N makes again and near above the layer 103 and following p section bar material zones 100) and second transducer.Thus, second transducer (it comprises layer 101) is shared by two sensor groups, and the first and the 3rd transducer that separates is positioned same vertical-horizontal place in this array.
Figure 10 A array can be configured to, and the blue light ingredient of first pixel is represented in the output of first sensor, and the blue light ingredient of second pixel is represented in the output of the 3rd transducer, and the green glow composition of first pixel and second pixel is represented in the output of second transducer simultaneously.Array preferably can operate in shown in Figure 10 A: the green glow good resolution is in the pattern of blue light (for example, by using the output of first, second and the 3rd transducer individually); And the blue light resolution pattern identical (for example, by the output of the first and the 3rd transducer is asked on average, and this mean value being used with the output of second transducer) with green glow resolution.Array shown in Figure 10 A is the simple embodiment that only has the transducer at two degree of depth places.In other embodiment of array of the present invention, sensor groups all has the transducer of vertical arrangement at three or more different depths.
In the VCF sensor group array shown in Figure 10 B, the ruddiness of each sensor groups and the carrier-collector elements of blue sensor have the big size of carrier-collector elements than the green sensor of this group.The array of Figure 10 B comprises a plurality of sensor groups, and wherein four have been shown among Figure 10 B.Each sensor groups comprises: a green sensor, and its carrier-collection areas (182,183,184 or 185) is not shared with any other sensor groups; A blue sensor, its carrier-collection areas (180) is shared with three other sensor groups; And a red light sensor, its carrier-collection areas (181) is shared with three other sensor groups.The carrier-collection areas that is used for blue light and red photons is greater than the collecting zone that is used for the green glow photon.(because of photonic absorption) collected electric charge is converted into the signal of telecommunication (normally voltage) on each red light sensor, and this signal of telecommunication is represented the mean value of the red light intensity of institute's incident on four sensor groups of shared this red light sensor.Collected electric charge is converted into the signal of telecommunication (normally voltage) on each blue sensor, and this signal of telecommunication is represented the mean value of the blue light strength of institute's incident on four sensor groups of shared this blue sensor.Usually, need not export the voltage output of the ruddiness of array shown in the calibration maps 10B (and variant) and blue sensor with respect to the voltage of green sensor, because be proportional to the increase of the sensor capacitance that the increase because of this carrier-collection areas causes because of the increase of carrier-collection areas in the transducer causes the increase of electric charge collected on each transducer.
When the array of making the VCF sensor groups makes that a pixel is determined in the output of each sensor groups, be necessary to make sensor groups to be isolated from each other to avoid crosstalking between the pixel.If the electronics and the hole that are produced in sensor groups can float among another, then the resolution of imager will descend.In preferred embodiment of the present invention, can just can realize this isolation by making the sensor groups that its physical Design comprises the electric charge that they inside produces.
For example, with reference to Figure 10 A, in the array of Figure 10 A, with n-p substrate knot the neighbour that following that bigger " second transducer " (comprising layer 101), the perpendicular degree of depth was identical (is partly illustrated, but unmarked) keep apart, just as less " first " and " the 3rd " transducer (comprising layer 102 and 103 respectively) being isolated from each other with n-p substrate knot.
Some conventional sensor arraies can not realized this isolation between those transducers of definite different pixels in its output.For example, (Figure 11 illustrates one type conventional sensors array, " Sensors and Actuators " A in Bartek, 41-42 (1994), describe to some extent among the pp.123-128) (for example be included in the middle photodiode sensor that produces of epitaxial silicon (epi) layer (31), and this layer epitaxial silicon is shared by all pixels photodiode 30).In this configuration, the electric charge that is produced in transducer can float in the adjacent transducer and maybe might float fartherly.Because the structure among Figure 11 lacks the area of isolation (for example, p N-type semiconductor N zone) between the transducer, so shared epitaxial loayer (layer 31) provides a passage, this passage can conduct to charge carrier below the one other pixel below a pixel.
The whole bag of tricks may be used to the transducer in the VCF sensor groups is isolated from each other, and the sensor groups (pixel) that perhaps will implement in the VCF sensor group array of the present invention is isolated from each other.Process integration is a key factor determining method therefor.A kind of available method is that knot is isolated, and this method generally is used for isolated transistor in silica-based technology.This knot must be able to tolerate the enough big voltage that is added in its two ends in case stopping leak leaks.In substrate or epitaxial loayer, can there be enough doping to isolate, isolate thereby perhaps may require between the adjacent area that will be isolated from each other, to increase doping realization knot so that sufficient knot to be provided.By using " injection " technology that is used for isolating adjacent transistors in the MOS technology, just can produce the doping of this increase.
Other embodiment of VCF sensor groups of the present invention and VCF sensor group array uses dielectric isolation, and this method is placed insulating material between semiconductor regions.Have oxide skin(coating) by in a semiconductive material, making each sensor groups and making below this sensor groups, just can realize this partition method.There are a variety of methods can produce this structure,, inject one deck oxygen and make oxygen and silicon reacts and forms oxide skin(coating), and from wafer, remove the silicon layer after the processing and it is transferred on the insulating substrate by the silicon wafer upper surface such as grown silicon on sapphire.
Dielectric isolation can be used for making the semiconductor transducer group in the VCF sensor group array to be isolated from each other.When sensor groups lateral displacement and when being formed in the bulk semi-conducting material each other, this isolation can realize as follows: form a plurality of groups at the top of insulating barrier, in this bulk semi-conducting material, etch groove, growth or deposition insulator in this groove.Usually, in some embodiments of the invention, be filled with insulator and semi-conducting material (to this semi-conducting material mix and in operating process biasing isolate to provide) at least a groove and/or the groove that comes lining with at least a in insulator and the semi-conducting material (for example, a kind of groove with the semi-conducting material lining, its doping content is higher so that leak passivation than the semi-conducting material piece between the segregate adjacent structure, fill with oxide or other insulating material then), be used to make VCF sensor groups of the present invention to be isolated from each other.In the CMOS technology, the use of this groove (to isolate conventional CMOS structure) is named as " trench isolations ".In exemplary embodiments of the present invention, trench isolations can be used to make the VCF sensor groups to be isolated from each other, because the ditch trench etch can be got enough dark so that several microns dark VCF sensor groups (such as, those sensor groups that produced in the typical silica-based VCF sensor group array) separated from one another.
Figure 12 shows the combination examples of dielectric isolation (realizing by trench isolations) and knot isolation.In Figure 12, a VCF sensor groups comprises the n type semiconductor layer 151,152 and 153 (for example, silicon) that is separated from each other on the vertical direction, and they all are formed in the p N-type semiconductor N material 150 (it can be a silicon).Provide contact 154 so that p section bar material 150 is coupled on the bias circuit.The plug of vertical orientation is connected to the upper surface of sensor groups with each layer 151 and 152, and each layer can be coupled to bias voltage and reading circuit like this.This plug can be by forming described in the above-mentioned U.S. Patent application 09/884,863 like that.The 2nd VCF sensor groups comprises the n type semiconductor layer 161 and 162 of vertical separation, and they also are formed in the p N-type semiconductor N material 150.With n-p substrate knot each transducer in the first sensor group is all kept apart with second sensor groups, just as the transducer in the first sensor group being isolated from each other with n-p substrate knot.Lateral isolation between first and second sensor groups realizes by trench isolations, promptly realizes isolating by groove 157, and groove 157 is with insulating material 158 (it can be silicon dioxide or the silicon nitride) lining that is formed between the two.Groove 155 (coming lining with oxide 156) is isolated first sensor group and the 3rd sensor groups (not shown among Figure 12, it is adjacent with the first sensor group) mutually.Insulating barrier 148 below each VCF sensor groups bottom sensor (it can be silicon dioxide or silicon nitride) also is used to sensor groups is isolated from each other.
Can be the lower shallow trench of length-width ratio (for example, 1/4th micrometers deep trench of common type in the number of C MOS integrated circuit) according to the present invention carrying out the used groove of trench isolations between the VCF sensor groups.Yet, usually, will be the higher darker groove of length-width ratio (for example, the groove of common type in some DRAM integrated circuits) carrying out the employed groove of trench isolations between the VCF sensor groups according to the present invention.
With reference to Figure 20-25, next employed a kind of improvement technology of providing the flush type layer to isolate of being used in the preferred embodiment of VCF sensor groups of the present invention is provided for we.In the operating process of each this embodiment of VCF sensor groups of the present invention, " non-collection " bulk semi-conducting material of a first kind (p type or n type) is always arranged between per two " carrier collection " sensor regions (opposite semiconductor type).In the non-collected volume of sensor groups, can produce photo-generated carrier (electronics or hole).Photo-generated carrier in the carrier-collection areas or produce elsewhere after the charge carrier of moving to again in the carrier-collection areas can collect by reading circuit.In some cases, the photo-generated carrier that produces in the non-collected volume of sensor groups can be moved in the carrier collection sensor region in the adjacent sensor groups.Usually, photo-generated carrier can be moved to (in a sensor groups or in different sensor groups) among at least two carrier collection sensor regions any from non-collected volume, to stop this migration is arranged on the direction of not expecting although can form barrier layer (for example, the barrier layer 205 among the Figure 20 that hereinafter will describe) according to the present invention.
As shown in figure 20, sensor groups can comprise: go up charge carrier collecting sensor zone (comprising the photodiode cathode 200 that is made of n N-type semiconductor N material); The sub-collecting sensor of download stream zone (comprising the photodiode cathode 202 that constitutes by n N-type semiconductor N material); Non-collection photodiode anode layer 201 and 203 between sensor region 200 and 202 (the p N-type semiconductor N material that comprises ground connection); And the non-collection photodiode anode layer 204 below sensor region 202 (the p N-type semiconductor N material that comprises ground connection).
In order in sensor groups, to provide isolation between each transducer to vertical separation, between the upper and lower portion of each non-collected volume are divided (thereby between transducer) lamination a kind ofly cover the barrier layer by what the higher semi-conducting material of the doping content of the first kind was made., used the term " lamination " of broad sense herein, this does not also mean that any specific method of use (for example, the physical engagement of isolating construction, or injection technology) forms and covers the barrier layer.For example, as shown in figure 20, sensor groups comprises between (thereby between the carrier collection sensor region that comprises negative electrode 200 and 202) between layer 201 and 203 and by what p section bar material constituted covers barrier layer 205.Last charge carrier collecting sensor zone (comprising negative electrode 200) can be " blue light " transducer, the sub-collecting sensor of download stream zone (comprising negative electrode 202) can be " green glow " transducer, and this group also can comprise be positioned at layer below 204 " ruddiness " transducer (not shown) and between layer 204 and red light sensor and by what p section bar material constituted, second cover the barrier layer.
Figure 21 is the function relation figure between the doping content and the degree of depth in sensor groups shown in Figure 20, the figure shows cathode layer 200 and 202 and barrier layer 205 between the position.In the operating process of sensor groups shown in Figure 20, the existence on barrier layer 205 can produce a kind of gradient electromotive force, this electromotive force guides in cathode layer 200 and 202 immediate one with light induced electron, their just can on the direction of not expecting, drift about (for example, from float to the negative electrode of negative electrode 202 or adjacent sensor groups near any of cathode layer 200 far awayly) like this.Because its position, barrier layer 205 also makes the electric capacity of transducer shown in Figure 20 be reduced to below the electric capacity of transducer in the sensor groups hereinafter shown in Figure 22.
With between the carrier collection sensor region of vertical stacking, place the way cover barrier layer (as shown in figure 20) according to the present invention and compare, Figure 22 shows and is placed on the vertical-horizontal identical with each carrier collection sensor region (or a little more down) with covering the barrier layer, this describes in above-mentioned U.S. Patent application 09/884,863 to some extent.This patent application 09/884,863 expressions, each (for example covers the barrier layer to go up injection in entire wafer (wherein will form the VCF sensor group array), the layer 206 and 207 that p N-type semiconductor N material shown in Figure 22 constitutes), cover the barrier layer is used for this array different sensors group with generation transducer by on selection area, injecting each then, thereby form carrier collection sensor region (for example, the n N-type semiconductor N material that comprises negative electrode 200 and 202 shown in Figure 22 constituted those zones).Prior art (patent application 09/884,863) and the present invention produced each cover the barrier layer and be intended to all to prevent that the charge carrier that is produced in the non-collected volume from vertically leaking in the carrier collection sensor region of same sensor groups (but not nearest carrier collection sensor region), prevent that also these charge carriers from flatly leaking in the non-collected volume of another sensor groups and then vertically leak into the carrier collection sensor region of this sensor groups.The example of " non-collected volume " is: the part (comprising p N-type semiconductor N material) of the anode layer 201 among Figure 22 in the middle of negative electrode 200 and 202; 205 very near but among Figure 20 from the part of negative electrode 200 anode layer 201 far away relatively from the barrier layer; And it is 205 very near but among Figure 20 from the part of negative electrode 202 anode layer 203 far away relatively from the barrier layer.
Figure 23 is the function relation figure between the doping content and the degree of depth in sensor groups shown in Figure 22, the figure shows cathode layer 200 and 202 and the position of barrier layer 206 and 207.In the operating process of sensor groups shown in Figure 22, barrier layer 206 and 207 existence have produced the electromotive force with gradient, this electromotive force allows the light induced electron in the layer 201 drift about (for example, from float to the negative electrode of negative electrode 202 or adjacent sensors group near any of cathode layer 200 far awayly) on the direction of not expecting.Because their position, barrier layer 206 and 207 also makes the electric capacity of transducer shown in Figure 22 increase to the electric capacity that is higher than above-mentioned transducer shown in Figure 20.
The present invention is used to locate and forms the technology of covering the barrier layer and has some advantages, this comprises that it has reduced the electric capacity of photodiode (thereby increased the output voltage of each photodiode and reduced to make each photodiode required time that resets between exposure), has also reduced (having surmounted the level that prior art can reach) photo-generated carrier and has leaked into the carrier-collection areas of mistake in the sensor groups or leak into probability in the adjacent sensors group.In operating process, compare with the use potential gradient that prior art produced, the potential gradient that produces between the carrier-collection areas of (sensor groups in) vertical separation according to the present invention provides higher electromotive force barrier layer, and it can prevent better that photo-generated carrier from leaking in the carrier-collection areas wrong in this group (or leaking in the adjacent sensor groups).
The sort of type of discussing except reference Figure 20 cover the barrier layer, some embodiments of the present invention are included in formed additional p type barrier region (that is, each this carrier collection sensor region is " laterally ") between the carrier collection sensor region of same depth in the adjacent sensor groups.For example, as shown in figure 24, in the p N-type semiconductor N material between the negative electrode of negative electrode 200 and same depth in adjacent sensor groups (not shown, for example the negative electrode on negative electrode 200 left sides and the right), can form additional barrier region 207 (comprising p N-type semiconductor N material).Figure 24 also shows additional barrier region 208 (comprising p N-type semiconductor N material), it is (not shown that it is formed at the negative electrode that negative electrode 202 is identical with the degree of depth in the adjacent sensor groups, for example, in the p N-type semiconductor N material 204 the negative electrode on the left side of negative electrode 202 and the right).The additional barrier zone 207 and 208 of laterally placing has changed the potential gradient between the carrier collection sensor region in the adjacent sensors group, thereby (for example reduced near first negative electrode, negative electrode 200) photo-generated carrier (electronics in the illustrated embodiment) that place, a certain position produces from the far negative electrode of this first negative electrode (for example floats to, float to the negative electrode of another sensor groups that is positioned at negative electrode 200 the right, not shown among Figure 24) risk.
Additional barrier layer 207 (with 208) is preferably by using the complementary injection technology of autoregistration to form, such as the described technology of reference Figure 25 A-25D.Perhaps, can use mask to them individually.Shown in Figure 25 A, on layer 201, produce silicon dioxide screen 209, Si 3N 4Mask is deposited on this silicon dioxide screen, etches this mask from the zone that will form negative electrode 200, and the ion implantation step produces n type negative electrode 200 below the expose portion of screen 209 then.Then, shown in Figure 25 B, growth layer of silicon dioxide barrier layer on the expose portion of screen 209.Then, shown in Figure 25 C, with Si 3N 4Mask peels off, and carries out another ion implantation step afterwards to produce p type barrier layer 207.At last, shown in Figure 25 D, the additional silicon dioxide of growth on the silica surface that total exposed is so that the shoulder height between the different piece of the silica surface that exposes minimizes.
During making the VCF sensor groups, the whole bag of tricks may be used in the top of other semi-conducting material or insulating material deposited semiconductor material.A kind of method be material from a wafer to another wafer physical transfer and this material to the joint of final wafer.This has stayed the sensor material of island on substrate.Can make these insulated with material with the dielectric of passivation, this is the another kind of version of dielectric isolation.Can produce it and leak all the same with block wafer good joint wafer, especially manufacturing process with the output feature can produce heat in joint wafer Si/SiO 2The interface.
With reference to Figure 14 A-14L, can explain below and use above-mentioned several manufacturing technologies to make one of VCF sensor groups shown in Figure 8 as how preferable mode.Preferable manufacture method allows in not expensive mode colour filter 43 and 48 to be included in the VCF sensor group array.The manufacturing technology (and variant) that will describe with reference to Figure 14 A-14L can be used to make other embodiment of VCF sensor groups of the present invention and array thereof, can also be used to make the semiconductor integrated circuit (for example, comprising transistorized circuit) of some type.
The result of several steps before Figure 14 A shows and carries out in this processing sequence, this preceding several steps is: inject n type layer 41 in p type substrate 40; Then, operate in growthing silica layer 42 on the substrate 40 by thermal oxide growth.Perhaps, layer 42 (and layer 44,47 and 49) can be made by another kind of dielectric substance, for example silicon nitride (SiN).
Figure 14 B carries out in this processing sequence the next result in a step, and this step is deposition on layer 42 " ruddiness by/blue or green light reflection " filter 43.Filter 43 can be layer SiN and SiO 2Replace the interferometric filter that constitutes.Perhaps, filter 43 can be the different material layer of refractive index (but not SiN and SiO 2Layer) interferometric filter that is constituted preferably, has and can equip the deposition formulation of carrying out with conventional CVD at this material.Filter 43 can be to absorb but " ruddiness passes through/blue or green light absorption " filter of remarkable reflect green light and blue ray radiation.
Figure 14 C shows following step in the processing sequence, and this step is that second wafer is contacted with the wafer shown in Figure 14 B.Specifically, second wafer comprises substrate 45 (p type silicon formation) and silicon dioxide layer (being grown on the substrate 45).Then, shown in Figure 14 D, 44 join the layer of second wafer filter 43 of (preferably by the thermal bonding step) first wafer to, so that filter 43 is clipped between silicon dioxide layer 42 and 44.More particularly, in manufacture process of the present invention, can use the joint of two wafers (on each wafer, all being formed with some layers of VCF sensor groups of the present invention).Multiple known joining technique may be used to make exemplary embodiments of the present invention, such as, people such as Pasquariello are at " Plasma-Assisted InP-to-Si Low Temperature Wafer Bonding " (the IEEE periodical of the selected theme of quantum electronics, volume 8, No. 1, in January, 2002/February) in the literary composition those technology are described.
Figure 14 E shows the result who carries out following step in the processing sequence, and this step is: reduce thickness if desired, then the thickness of p type wafer 45 is reduced to the thickness of expectation.Be polished to about 0.5 micron thickness by exposed surface, or by riving with wafer 45, or by some other means, just can realize the above-mentioned thickness that reduces.
Figure 14 F and 14G show and carry out in the processing sequence the next result in several steps, and these several steps are: inject n type layer 46 in wafer 45; Then by thermal oxide growth operate in that wafer 45 exposes (on) growthing silica layer 47 (shown in Figure 14 F) on the surface; Then shown in Figure 14 G, deposition filter layer 48 on silicon dioxide layer 47 (it can but do not need to comprise the SiN material).Figure 14 H shows following step in the processing sequence, and this step is that the 3rd wafer is contacted with the wafer after engaging and handling shown in Figure 14 G.Then, shown in Figure 14 I, with the layer 49 of the 3rd wafer join that layer 48 exposes to (on) surface (preferably by the thermal bonding step) so that layer 48 is clipped between silicon dioxide layer 47 and 49.
Layer 47,48 and 49 (shown in Figure 14 I) comprise an interferometric filter jointly, and it can serve as " gold-tinted passes through/blu-ray reflection " filter.Perhaps, on structure shown in Figure 14 G, produce piling up of additional SiN layer and silicon dioxide layer earlier, join the 3rd wafer (wafer of Figure 14 H shown type) to top that this piles up again, thereby formed the interferometric filter that SiN and silicon dioxide alternately constitute more than three layers.In other optional embodiment, can on structure shown in Figure 14 E, form the interferometric filter that (this piles up and does not comprise SiN and silicon dioxide layer) constitutes that piles up by the different material layer of refractive index, join the 3rd wafer (wafer of Figure 14 H shown type, but might with the silicon dioxide layer 49 among the non-earth silicon material layer alternate figures 14H) to top that this piles up again.Filter 47,48 and 49 can be " gold-tinted passes through/blue light absorption " filter, and its absorbs but significantly reflect blue radiation.Shown in Figure 14 H, the 3rd wafer comprises substrate 50 (being made of p type silicon) and silicon dioxide layer 49 (being grown on the substrate 50).Multiple known joining technique may be used to realize with reference to the described engagement step of Figure 14 I, and this comprises in the method described in people's such as above-mentioned Pasquariello the paper some.
Figure 14 J shows the result who carries out in the processing sequence next step, and this step is: reduce thickness if desired, then the thickness of p type substrate 50 is reduced to the thickness of expectation.Be polished to about 0.3 micron thickness by exposed surface, or by riving with substrate 50, or by some other means, just can realize the above-mentioned thickness that reduces.
Figure 14 K shows the result who carries out in the processing sequence next step, and this step is to inject n type layer 51 in substrate 50.Then, shown in Figure 14 L, carry out last CMOS treatment step.These last steps comprise the formation (finishing of the process of formation contact) of passivation, contact and shadow shield 54 are installed in position.
Be to use the last structure shown in Figure 14 L, need to make from each layer 41,46 and 51 extend to that this structure exposes (on) contact on surface.Preferably, form contact in the mode described in mode described herein or the U.S. Patent application 09/884,863.With reference to Figure 15-15H, a kind of preferred technique that is used to make this contact is described below.
Preferably by using the groove Etaching device of common type in high performance analog bipolar (or DRAM) technology, form the low plough groove type contact that leaks with reference to the described technology of Figure 15 A-15H.
Figure 15 A shows the result who carries out the first step in the processing sequence, and this step is to etch a silicon layer 50 that penetrates structure shown in Figure 14 L and 51 and arrive the groove of dielectric layer 49.
Next, shown in Figure 15 B, this groove is extended to silicon layer 45 with suitable etch process (for example, when layer 47,48 and 49 is made of SiN or silicon dioxide, can use oxide etching process).Next, shown in Figure 15 C, silicon etch process extends to dielectric layer 44 with this groove.Next, shown in Figure 15 D, this groove is extended to silicon layer 40 with suitable etch process (for example, when layer 44,43 and 42 is made of SiN or silicon dioxide, can use oxide etching process).
Next, shown in Figure 15 E, regularly silicon etch process extends to n type silicon cathode layer 41 (negative electrode of red light sensor) with this groove.
Next, shown in Figure 15 F, growthing silica passivation layer 301 on the surface of these all exposures of groove preferably, thus added lining with insulator for this groove.Next, shown in Figure 15 G, carry out anisotropic etching and also be deep into cathode layer 41, thereby only remove insulator and the n type silicon materials of cathode layer 41 are come out from this channel bottom.
Finally, shown in Figure 15 H, fill this groove, thereby finished the contact groove that extends to layer 41 with n type polycrystalline silicon material 302.The top of this contact groove can be directly coupled to bias voltage and reading circuit (for example, being coupled to the grid that source electrode is followed amplifier transistor 56r shown in Fig. 2 A).
In forming the solid pieces of material of VCF sensor groups of the present invention, can produce groove and fill, to form contacting to embedded-type sensor negative electrode and anode with semi-conducting material.For example, can the semi-conducting material around the groove be mixed, the passivation layer of being grown on the semi-conducting material that mixes is as the lining of this groove then, the bottom that can open this groove then (for example, pass through anisotropic etching), use n N-type semiconductor N (for example, the n+ polysilicon) to fill the groove of opening then, it just can serve as the n type contact of flush type n type negative electrode like this.Perhaps, can be the groove lining and/or fill this groove with insulating material, so that the VCF sensor groups is isolated from each other with insulating material.Compare with the plug that diffusion forms that passes through described in the U.S. Patent application 09/884,863, can make contact groove (or isolation structure) make narrowlyer.By using prior art to be easy to produce cross section is that 0.5 micron, the degree of depth are several microns groove, thereby form the contact groove that extends to very dark transducer in typical VCF sensor groups.This cross section is more much smaller than the minimum cross-section of the plug (having the identical degree of depth) of diffusion, and this plug can be produced with prior art is cheap.Can the improve the standard fill factor, curve factor of the array that the VCF sensor groups of separating on the direction constituted of the use of contact groove (or groove isolation construction) because they can increase incident radiation in the imaging plane can by the sensor of VCF sensor groups to area (and can reduce the area that stopped by shadow shield in the imaging plane or by the occupied area of structure that incident radiation is not converted to detectable electronics or hole).
In preferred embodiment, form at least one plug by multistage injection technology in the VCF sensor groups, the cross section of the diffusion type plug that this technology is produced is much smaller than the minimum cross-section of the diffusion type plug that can produce very cheaply with prior art (having the identical degree of depth).As shown in figure 17, n type plug (about 2 microns degree of depth below the n type negative electrode of " green glow " transducer, about 2.6 microns degree of depth below the sensor groups end face of making) to the n type negative electrode of " ruddiness " transducer can form by prior art: with phosphorus (its energy is 1200KeV) inject p type silicon exposed surface (from the upper surface of the sensor groups made about 1.3 microns dark) to form the bottom of this contact; On the surface of this exposure, form additional structure (comprising p type silicon epitaxy layer) then; Then phosphorus (its energy is 500KeV) is injected the new surface that exposes of p type silicon (from the upper surface of the sensor groups made about 0.6 micron dark) to form the top of this contact.Yet as shown in figure 17, this causes contact to have excessive diameter (2.2 microns or bigger diameter, this depends on n type doped level used in the technology and the number of times of thermal cycle).In addition, in the manufacture process of contact, on sensor groups, place the demand (injecting not desired region of arrival sensor groups) of thick (for example 3 microns) photoresist layer, make the size in the sensor groups feature that can form reach minimum to prevent high energy phosphorus as 1200KeV.
The technology used with producing contact shown in Figure 17 compared, and hereinafter will describe the embodiment of a kind of multistage injection technology that (with reference to Figure 18 and 18A) carry out according to the present invention.Of the present invention multistage injection technology shown in Figure 18 and the 18A is (for example, by being that the arsenic of 60KeV is injected in the p type substrate with energy) (for example form target, red light sensor negative electrode 310 shown in Figure 180, it is made of n type silicon) just carry out afterwards, and can produce its diameter and be about 0.5 micron and extend to the joint of about 2 microns dark targets in the sensor groups.This technology comprises four steps.
The first step is to form first epitaxial loayer (for example, as shown in figure 18, forming p type silicon layer 311 on photodiode cathode 310) on that target that contact extends to.
Inject by in first epitaxial loayer (311), carrying out ion, formed the bottom (for example, the plug portion among Figure 18 312 and 313) of plug.For this reason, on layer 311, form thin nitride mask 314, in mask 314, produce little mask hole 318 (its diameter is about 0.5 micron) then, pass aperture 318 then and inject arsenic, be about 1 micron thickness generally at layer 311, the bottom of plug needs to see through 311 on layer and extends a very short distance (1 micron).When using such mask and such first epitaxy layer thickness, by with energy be the arsenic of 1200KeV be injected into the first 312 that just can form the plug bottom in the layer 311 (from layer 310 extend to layer 310 or more about 0.7 micron), then by being that the arsenic of 500KeV is injected into the second portion 313 (extending about 0.3 micron to layer 311 end face from part 312) that just can form in the layer 311 bottom the plug with energy in first 312.
According to the present invention, (for example, arsenic) advantage is, can allow to use thin many masks like this, and this can be clear that from Figure 19 to inject its diffusivity material lower than phosphorus.Necessary mask thickness when Figure 19 shows and points out that to five kinds mask material injects boron, phosphorus, arsenic and antimony.For example, Figure 19 points out, can be about 0.07 micron Si by used thickness during arsenic injection (injecting with 100KeV) 3N 4Mask, and when injecting phosphorus with identical energy can need thickness greater than 0.15 micron Si 3N 4Mask.
The 3rd step was to remove mask 314 from first epitaxial loayer 311, formed second epitaxial loayer (epitaxial loayer 315 among Figure 18 A, it is made of p type silicon) then on first epitaxial loayer 311.
Inject by in second epitaxial loayer (315), carrying out ion, formed the top (for example, the plug portion 316 and 317 among Figure 18 A) of plug.For this reason, on layer 315, form thin nitride mask 319, in mask 319, produce little mask hole 320 (its diameter is about 0.5 micron) then, pass aperture 320 then and inject arsenic, be about 1 micron thickness generally at layer 315, the top of plug only need see through layer 315 and extend a very short distance (1 micron).When using such mask and such second epitaxy layer thickness, by being that the arsenic of 1200KeV is injected into the first 316 that just can form the plug bottom in the layer 315 (above layer 311 extends to layer 311 about 0.7 micron) with energy, then by being that the arsenic of 500KeV is injected into the second portion 317 (315 push up about 0.3 micron of extension from part 316 to layer) that just can form the plug bottom in the layer 315 in first 316 with energy.
More particularly, a class embodiment of the present invention uses its diffusivity material lower than phosphorus (preferably, use arsenic (As), but not normally used phosphorus (P)) to carry out the diffusion type plug and forms necessary implantation step.This material (having low diffusivity) and phosphorus than horizontal direction diffusely still less allow to form narrower plug thus, so just can produce the sensor groups that fill factor, curve factor increases.Although arsenic has much lower diffusivity (vertical and horizontal proliferation rate) than phosphorus, multistage injection technology of the present invention (having described the typical case of this technology with reference to Figure 18,18A and 19) makes injection arsenic (but not phosphorus) form the diffusion type plug and becomes feasible.This be because: in multistage injection technology, arsenic only need vertically pass each epitaxial loayer diffusion very short distance relatively; And pass very long distance (for example, the top from sensor groups is diffused into the flush type target that joint extends to far awayly) in the conventional method that the diffusion type plug forms.
The variant of above-mentioned multistage injection technology (with reference to Figure 18,18A and 19) has used low diffusivity material and/or more than three epitaxial loayers on target beyond the arsenic removal.In each epitaxial loayer, formed the different piece of this joint.
When on wafer, making VCF sensor groups (or VCF sensor group array), can go up at least one transistor of formation (be used to be coupled at least one transducer of each the VCF sensor groups) " end " of this wafer face (opposite) with " top " face of this group of the radiation incident that will detect.The fill factor, curve factor of the array of the VCF sensor groups of on the bottom surface of wafer (but not end face of this group) this transistor of last formation can be improved the standard direction, separating.In the many different embodiment of VCF sensor groups of the present invention and VCF sensor group array, can on the bottom surface of wafer, form transistor.
Hereinafter be described in the example that also forms transistorized method on the bottom surface that forms VCF sensor groups and this wafer on the wafer with reference to Figure 16 A-16H.Figure 16 A-16H supposition comprises that the structure (shown in Figure 16 A) of unit 40,41,42,43,44,45,46,47,48,49,50 and 51 is pre-formed.Identical shown in this structure and Figure 14 K, and will be called as " master " structure.To no longer repeat about the description of main structure and the method for making it.
Shown in Figure 16 A, " handle " wafer (being made of the insulating barrier 90 on p N-type semiconductor N substrate material 91 and the substrate 91) is aimed at main structure, and the top layer 50 of main structure faces the insulating barrier 90 of handle wafer.
Then, shown in Figure 16 B, with the layer 90 of handle wafer join to layer 50 exposure (on) surface (preferably by the thermal bonding step) be clipped between p type semiconductor layer 50 and the p N-type semiconductor N substrate 91 so that layer 90 becomes.
The bottom surface polishing that substrate 40 is exposed to be reducing its thickness (shown in Figure 16 C), thereby transducer (comprising red light sensor cathode layer 41, green sensor cathode layer 46 and green sensor cathode layer 51) can be connected to from the bottom.Then, shown in Figure 16 C, the structure of gained is inverted, " end " of 40 exposures of the unit after the polishing is just face has become the end face of Figure 16 C like this.
Shown in Figure 16 D, formed contact groove (96), 40 " end " faces (top of Figure 16 D) that expose extend to blue sensor cathode layer 51 from the unit for it.This can realize by the described mode of reference Figure 15 A-15H.Then, preferably, on the bottom surface of unit 40 exposures, formed support circuits 92 by the semiconductor integrated circuit manufacturing process.Support circuits 92 comprises that at least one is coupled to the transistor (at the top of Figure 16 D) of contact groove 96 bottoms.Formed another contact groove (not shown), 40 bottom surfaces that expose extend to green sensor cathode layer 46 from the unit for it.Formed the 3rd contact groove (not shown), 40 bottom surfaces that expose extend to red light sensor cathode layer 41 from the unit for it.At least one transistor of support circuits 92 is coupled to each layer 41,46 and 51 by the contact groove.
Shown in Figure 16 E, second " handle " wafer (it comprises p N-type semiconductor N substrate material 94 and the insulating barrier on substrate 94 93) aimed at the structure shown in Figure 16 D, and (end) face of the exposure of the p N-type semiconductor N substrate of unit 92 faces insulating barrier 93.
Then, shown in Figure 16 F, join the layer 93 of second handle wafer to surface (preferably by the low temperature engagement step) that unit 92 exposes, so that layer 93 becomes between the p N-type semiconductor N substrate and p N-type semiconductor N substrate 94 that is clipped in unit 92.
Then, remove substrate 91 (for example, grinding off), and the structure shown in Figure 16 F can be inverted (shown in Figure 16 G, the bottom surface that substrate 94 exposes faces down like this, and the end face that layer 90 exposes faces up).
Then, support circuits 92 can be coupled to bias voltage and reading circuit.For example, shown in Figure 16 H, support circuits 92 can be coupled to bias voltage and reading circuit 96 by shell case structure 95, and this shell case structure 95 has realized the contact between each transistor AND gate circuit 96 of support circuits 92.Can use commercial method (for example, Shellcase Co., Ltd developed method) to produce shell case structure 95.Bias voltage and reading circuit 96 can be with reference to the described the sort of type of Fig. 2 A.
Producing the another kind of method of isolating (for example, between adjacent VCF sensor groups) is to use the MOS transistor of cut-out as isolation structure.This is to realize with thick oxide transistor, and this transistorized grid perhaps also can be realized with the MOS transistor of another kind of type isolating round the top layer of wanting segregate sensor groups (wherein making this grid remain on voltage far below threshold value).The MOS transistor of cutting off can be used near the semiconductor regions the insulation surfaces, but path very dark in the substrate is not had too much influence.Therefore, its partition method best and with reference to the described the sort of type of Figure 20-24 is used in combination, so that adjacent VCF sensor groups is isolated from each other.
The example of the partition method of mentioning in the preceding paragraph is an annular isolation, by forming thick or thin oxide M OS transistor (its grid is round the top layer of wanting segregate sensor groups), just can realize this annular isolation.In operating process, give the grid biasing to cut off this transistor.
Existing big metering method may be used to make the VCF sensor groups, and best method depends on material and the requirement that is used for this sensor groups under the various situation.
Structure in the silicon can and be injected with epitaxial growth and make up, for example, as described in the above-mentioned U.S. Patent application 09/884,863 like that.Ion is provided by a kind of method that makes up junction structure below silicon face that provides.By using high energy (greater than 400KeV) to inject, very dark structure also is possible.Because compare with the structure that can produce with the high energy injection, the VCF sensor groups requires thicker silicon structure usually, capture the required very dark structure of photon so usually epitaxial growth and injection are combined use to produce (according to the present invention), thereby the depths is that electrons/is right with photon conversion in silicon.
In some embodiments of the invention, the another kind of method that is used for producing deep structure is that silicon engages.This method joins a kind of semiconductive or insulation material layer to another layer on the molecule aspect.For example, might in a silicon wafer, create structure, engage very thin one deck silicon then at its top.Also might engage foreign peoples's semiconductor.For example, when carrying out suitable material preparation, III-V family semiconductor interface can be incorporated on the silicon.Because the coefficient of expansion of two kinds of materials is different, so the island III-V family material on the silicon body can't be very big.Yet, greatly to the island III-V family material of the exemplary embodiments that enough can form VCF sensor groups of the present invention (for example, above with reference to the described In of Fig. 7 xGa 1-xThe N material) still can join on the silicon.A significant advantage of doing like this is, compare with silicon, can select for use in the different wavestrips of III-V family absorbed radiation (for example, some III-V family material transmission all or all green glow incident thereon and red light radiation basically, although silicon has sizable absorptance to green-light radiation and to the absorptance of green-light radiation much larger than absorptance to red light radiation).Therefore, and compared by each transducer that silicon constituted of III-V family material underneath, can realize such sensor groups, wherein each transducer that is made of III-V family material absorbs the radiation in the different wavestrips.
For filter being added in the vertical stratification (for example, the VCF colour filter), might in the bulk semi-conducting material, produce groove (or other space), fill this space with (for example, slurry) filter material of liquid or other flow-like then.A kind of implementation method is to use horizontal silicon monocrystal growth so that form the space in the bulk semi-conducting material, then oxide (the laterally oxide that exists in the silicon monocrystal growth step) is etched away.Can be used for etching step such as liquid state etching agent such as hydrofluoric acid.When under silicon, forming the space, can fill this space with liquid filter (or flow-like but non-liquid state).This filter will be cured (for example, handling by heat treatment or UV) to form VCF sensor groups structure.Perhaps, the ion by oxygen injects, and is exactly thereafter that wafer and the oxygen that injected react and the stage of reaction that produces silicon dioxide, just can form oxide areas.
Hereinafter process described in the preceding paragraph is described in more detail with reference to Figure 13 a-13f.Figure 13 a shows the silicon dioxide region 170 that forms and injected on the surface of p N-type semiconductor N 171 (it can be a silicon) the n N-type semiconductor N zone 172 that is used for below silicon dioxide region 170, producing p-n junction.The zone of being injected 172 will become one of a plurality of transducers of VCF sensor groups.Figure 13 B also shows from upwardly extending first plug of the right hand edge in zone 172 and injects (being made of n N-type semiconductor N material).
Figure 13 b shows and uses the p N-type semiconductor N material 171 (it can be silicon) identical with 171 types of semiconductor shown in Figure 13 a to carry out epitaxial growth in addition and covered identical cross-section after the silicon dioxide region 170.Transversal epitaxial growth has been used for semi-conductor industry to produce the monocrystalline silicon of dielectric isolation.Shown in Figure 13 c, (being made of n N-type semiconductor N material) injected on the nearly surface of formation on silicon dioxide region 170, and formed second plug injection (being made of n N-type semiconductor N material) of injecting the upper surface that extends upwardly to semiconductor 171 from first plug.These two plugs inject and have formed the plug that is used for layer 172 is coupled to bias voltage and reading circuit together.
Shown in Figure 13 d, next step is to etch away abundant material 171 to form a groove that following silicon dioxide region 170 is exposed.Then, carry out SiO 2 etch so that from zone 170, remove oxide (silicon dioxide), thereby below upper surface 173, stayed a space like that shown in the image pattern 13e.Finally, fill this space (shown in Figure 13 f) with liquid filter 174 and material 174 is solidified.Perhaps, filter 174 is fluid and on-liquid.
Variant with reference to the described method of Figure 13 a-13f can be used to form the VCF sensor groups that has the transducer of two or more vertical separation below filter regions (being filled with the zone of filter 174).
In some embodiment of VCF sensor groups of the present invention, with semiconductive material and amorphous silicon is deposited on wafer or other substrate.Two examples of this semiconductive material are amorphous silicon and polysilicon.
Can come deposit amorphous silicon by number of chemical gas deposition and sputtering technology.When using SiH,, just can deposit and have high-quality amorphous silicon by the plasma auxiliary chemical gas deposition as source gas.By adding a spot of other hydride (such as hydrogen phosphide, arsine and diborane), just can realize doping to the amorphous silicon of deposition.(by produce the pn knot in amorphous silicon) just can be used as transducer, filter with amorphous silicon in the VCF sensor groups, or simultaneously as filter and transducer.Amorphous silicon has been used for the photoimaging array.Residing low temperature during deposit amorphous silicon (less than 400 degrees centigrade) has an advantage, because it has only increased the diffusion of impurity a little and can coordinate with some filters.
In a similar manner, polysilicon can be formed on semiconductor wafer or other substrate.Usually, first deposit amorphous silicon, and then crystallize into polysilicon.By injecting or can mixing to produce the pn knot to polysilicon from sedimentary deposit.Transistor also can form in amorphous silicon or in the polysilicon, and can be used to the address sensor of VCF sensor groups.
Various filters and filter combination can be included in the VCF sensor groups of the present invention, so that better photon separation, color accuracy and sensor resolution to be provided.For example, the array of VCF sensor groups can combine with organic colour filter of common type in the imageing sensor manufacture process.Filter can be formed at by the pattern of chessboard sample on the subclass of sensor group array (or being included in wherein), so that governing response is in the color response of the sensor groups of blue light and red illumination.When using the pattern of this filter, each filbtercharacteristic can be very simple and insensitive to making variation, and this is because this filter is relevant with the semiconductor colour filter characteristic of each VCF sensor groups.The advantage that is obtained is that a kind of colour filter that may more make us expecting responds.Perhaps, organic, dielectric, polysilicon filter can place on the subclass of VCF sensor group array (or being included in wherein) by the mode of alternately arranging, each another sensor groups in response to particular color also has a colour filter that is used to make the color response setting like this, thereby has produced an array with six kinds of different colours responses.A kind of technology in back allows a variety of color response, makes simultaneously to be placed with machine filter mating plate (or filter of other type) at the surperficial top of imageing sensor or filter is included in manufacturing expense required in the VCF sensor groups to reach minimum.
Although this paper has described the optimal mode of realizing the present invention and application of the present invention, but for one of ordinary skill in the art, clearly under the situation of the scope that does not deviate from described herein and requirement, might make many changes to embodiment described herein and application.Should be appreciated that although illustrated and described some form of the present invention, the present invention is not limited to specific embodiment or the described ad hoc approach that institute describes and illustrates.In addition, the claims that are used for describing method are not specified any specific order to all steps, unless offer some clarification in the claim language.

Claims (12)

1. sensor groups comprises:
A solid material, has the transducer of reading the surface and wherein having formed at least two vertical stackings, wherein each transducer has different spectral responses, and described transducer comprises the multi-lager semiconductor material and is configured to biasing to serve as photodiode; And
At one of described transducer and the described contact groove of reading between the surface, one of wherein said transducer has the carrier collection district, described carrier collection district comprises the semi-conducting material with first polarity, described contact groove have the bottom, in the described contact groove except that described bottom all with electrical insulating material do lining and then again apparatus have the semi-conducting material of described first polarity to fill or do lining.
2. sensor groups as claimed in claim 1 is characterized in that, described contact point is that apparatus has the semi-conducting material of described first polarity to make lining.
3. sensor groups as claimed in claim 1 is characterized in that, described contact point is that apparatus has the semi-conducting material of described first polarity to fill.
4. sensor groups as claimed in claim 1 is characterized in that, described material block has the upper surface of wanting detected radiation to pass, and the described surface of reading is exactly described upper surface.
5. sensor groups comprises:
A solid material, it has upper surface and lower surface, and wherein formed the transducer of at least two vertical stackings, want detected radiation can pass described upper surface, wherein each transducer has different spectral responses, described transducer comprises the multi-lager semiconductor material, and described transducer is configured to biasing to serve as photodiode;
Contact point between one of described transducer and described lower surface; And
The transistor that at least one forms on described lower surface, one of wherein said transducer has the carrier collection district, described carrier collection district comprises the semiconductor with first polarity, and described contact point is that apparatus has the semi-conducting material of described first polarity to fill or do the groove of lining.
6. sensor groups as claimed in claim 5 is characterized in that described transistor is formed on the described lower surface by the semiconductor integrated circuit manufacturing process.
7. sensor groups as claimed in claim 5 also comprises:
Be coupled to described transistorized bias voltage and reading circuit.
8. sensor groups as claimed in claim 5 is characterized in that, described contact point is that apparatus has the semi-conducting material of described first polarity to fill.
9. sensor groups as claimed in claim 5 is characterized in that, described contact point is that apparatus has the semi-conducting material of described first polarity to make lining.
10. method of making the vertical color filter sensor groups, described method comprises the steps:
(a) provide a solid material, it has upper surface and lower surface, detected radiation can pass described upper surface; And
(b) at least a semiconductor integrated circuit manufacturing process is applied to described material block so that form a kind of structure that comprises the transducer of at least two vertical stackings, wherein said structure comprises the transducer of at least two vertical stackings, each transducer has different spectral responses, described transducer comprises the multi-lager semiconductor material, described transducer is configured to biasing to serve as photodiode, and described structure is included in contact point between one of described transducer and the described lower surface and transistor that at least one forms on described lower surface, one of wherein said transducer has the carrier collection district, described carrier collection district comprises the semiconductor with first polarity, and step (b) comprises the steps:
Between one of described transducer and described lower surface, form groove; And
Apparatus has the semi-conducting material of described first polarity to fill described groove or makes lining for described groove.
11. method as claimed in claim 10 is characterized in that, step (b) comprises the steps:
Apparatus has the semi-conducting material of described first polarity to fill described groove.
12. method as claimed in claim 10 is characterized in that, step (b) comprises the steps: that it is that described groove is made lining that apparatus has the semi-conducting material of described first polarity.
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