CN104112782B - Anti-crosstalk reverse-U-shaped buried layer photodiode and generation method - Google Patents
Anti-crosstalk reverse-U-shaped buried layer photodiode and generation method Download PDFInfo
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- 238000000034 method Methods 0.000 title claims abstract description 21
- 239000000758 substrate Substances 0.000 claims abstract description 10
- 238000002513 implantation Methods 0.000 claims description 52
- 238000002347 injection Methods 0.000 claims description 33
- 239000007924 injection Substances 0.000 claims description 33
- HAYXDMNJJFVXCI-UHFFFAOYSA-N arsenic(5+) Chemical group [As+5] HAYXDMNJJFVXCI-UHFFFAOYSA-N 0.000 claims description 32
- 239000012535 impurity Substances 0.000 claims description 15
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 13
- 229910052796 boron Inorganic materials 0.000 claims description 12
- 230000003071 parasitic effect Effects 0.000 claims description 8
- 229910052757 nitrogen Inorganic materials 0.000 claims description 7
- OAICVXFJPJFONN-UHFFFAOYSA-N Phosphorus Chemical compound [P] OAICVXFJPJFONN-UHFFFAOYSA-N 0.000 claims description 2
- 229910052698 phosphorus Inorganic materials 0.000 claims description 2
- 239000011574 phosphorus Substances 0.000 claims description 2
- 230000005622 photoelectricity Effects 0.000 claims 1
- 230000005684 electric field Effects 0.000 abstract description 9
- 238000009792 diffusion process Methods 0.000 abstract description 5
- 230000009471 action Effects 0.000 abstract description 2
- 230000007246 mechanism Effects 0.000 abstract description 2
- 230000006698 induction Effects 0.000 abstract 5
- 239000000969 carrier Substances 0.000 abstract 2
- -1 boron ion Chemical class 0.000 description 17
- 230000000694 effects Effects 0.000 description 9
- 150000002500 ions Chemical class 0.000 description 6
- 238000005286 illumination Methods 0.000 description 4
- 238000010586 diagram Methods 0.000 description 3
- 230000035755 proliferation Effects 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 2
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- 230000005611 electricity Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 238000000407 epitaxy Methods 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 230000010354 integration Effects 0.000 description 1
- 238000005468 ion implantation Methods 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 238000001259 photo etching Methods 0.000 description 1
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- 230000003595 spectral effect Effects 0.000 description 1
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- 238000003892 spreading Methods 0.000 description 1
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Abstract
The invention discloses an anti-crosstalk reverse-U-shaped buried layer photodiode and a generation method. The anti-crosstalk reverse-U-shaped buried layer photodiode comprises a surface P+ clamping layer on the upper portion of a P-type epitaxial layer, an initial N-type light induction area arranged on the lower portion of the P-type epitaxial layer, two ring-shaped P-type light dope buried layers arranged below the initial N-type light induction area, and secondary N-shaped light induction buried layers arranged in the ring-shaped P-type light dope buried layers. According to the anti-crosstalk reverse-U-shaped buried layer photodiode and the generation method, a built-in electric field where the P-type light dope buried layer to the P-type epitaxial layer is established, so that carriers stimulated by long-band incident light produced in the epitaxial layer and a substrate are drifted to a top layer light induction N buried layer under the action of forces of the built-in electric field and collected, transverse diffusion of charges is prevented, and a charge crosstalk phenomenon is inhibited; reduction of a charge crosstalk rate, produced by a diffusion mechanism, of the carriers stimulated by long-band light between adjacent pixel units can be guaranteed under the condition that filling factors in the light induction area are not lost, and key indexes of full trap capacity, quantum efficiency and the like are improved.
Description
Technical field
The invention belongs to cmos field of image sensors, particularly to a kind of resistance to crosstalk inverted u shape buried regions photodiode and
Generation method.
Background technology
Cmos imageing sensor with its low-power consumption, low cost and can with cmos semiconductor integrated circuit manufacturing process and
The advantages of appearance, progressively replaces ccd and occupies imageing sensor mainstream market.It is photosensitive unit using clamper photodiode (ppd)
Dot structure further reduces the indexs such as the reset noise of sensor, dark current, fixed pattern noise, and can pass through phase
Close double-sampling compensating image quality, these advantages make ppd pixel be widely used in modern high performance cmos imageing sensor
In.
Conventional ppd image element circuit be by a clamper photodiode, floating diffusion node, transfer tube, reset transistor, source with
Switch is selected to collectively constitute with device and row, clamper photodiode is by the n buried regions of injection in p-type epitaxial layer, surface p+clamper
Layer and p-type epitaxial layer collectively constitute, and this photoelectric diode structure is used for receiving incident photon, and produces and light intensity of incident light and ripple
The corresponding signal charge of appearance exports, and the injection of p trap is to suppress photosensitive depletion region horizontal expansion.
With the progress of cmos technique, cmos image sensor pixel cells size reduction, integration density increases so that phase
Physical distance between adjacent pixel is less and less, causes serious crosstalk effect, causes output image resolution and uniformity fall
Low, affect image quality.So-called crosstalk effect, can be divided into two classes, and a class is that light reached neighbor before being completely absorbed
Position or through connected medium layer reflection and refraction and enter neighbor photosensitive area, referred to as optical crosstalk；Another kind of is that light enters
It is mapped to substrate and excites electric charge, it had certain probability before spreading go back to depletion layer uptake zone and occurs horizontal proliferation to enter adjacent
The photosensitive uptake zone of pixel and be collected, referred to as electric charge crosstalk, especially for compared with long-wave band light, it absorbs depth and is far below depletion layer
Uptake zone, electric charge crosstalk phenomenon can be more significantly.Therefore consider the impact of crosstalk effect, above-mentioned routine ppd dot structure will
Can be disturbed by neighbor, reduce image analytic degree, there is certain limitation in the application.
Research to crosstalk effect has the achievement partly published both at home and abroad at present, especially for electric charge crosstalk,
Propose some solutions, be summarized as three kinds: the first is to increase active area between adjacent pixels and inject p+ protection ring,
Photogenerated charge for resulting from substrate provides low-resistance to release path so as to other pixels cannot be diffused to, and the method can significantly increase
Plus sensor chip area, also it is unfavorable for the design of photosensitive area fill factor, curve factor；Second is to increase the doping content of epitaxial layer, fall
Low minority carrier lifetime and diffusion length, make electric charge compound before diffusing to the photosensitive uptake zone of neighbor, its drawback
It is that the increase of p-type epitaxial layer concentration is unfavorable for that depletion region epitaxial layers extend, the absorption of impact long-wave band light, reduce quantum
Efficiency, makes limited by sensor spectral response range；The third is using deep trench isolation technique (dti), and pixel cell is carried out electricity
Air bound is from the method is limited to technological level, also increases dark current generation rate it is more difficult to be used widely.
Content of the invention
It is an object of the invention to overcoming above-mentioned deficiency, provide a kind of resistance to crosstalk inverted u shape buried regions photodiode and generation
Method, ensure that on the premise of photosensitive area fill factor, curve factor is not lost, reduces and swash compared with long-wave band light between adjacent pixel unit
Send out the electric charge crosstalk ratio of carrier, and lift the pixel Key Performance Indicators such as full trap ability, quantum efficiency, enable the sensor to carry
For high-res, high-quality image.
In order to achieve the above object, a kind of resistance to crosstalk of present invention inverted u shape buried regions photodiode, including p-type epitaxial layer and
In the p-substrate of its underpart, p-type epitaxial layer top is provided with surface p+clamper layer, and surface p+clamper layer bottom is provided with initial n
Type photosensitive area, the p-type being provided with two-layer annular below initial N-shaped photosensitive area is lightly doped buried regions, and p-type is lightly doped buried regions ring-shaped inner part
It is provided with the photosensitive buried regions of secondary N-shaped.
A kind of generation method of resistance to crosstalk inverted u shape buried regions photodiode, comprises the following steps:
Step one: injection arsenic ion forms initial N-shaped photosensitive area in p-type epitaxial layer；
Step 2: the injection boron ion on initial N-shaped photosensitive area forms p+ clamper layer；
Step 3: inject ratio with around epitaxial layer intersection using lp mask blank below initial N-shaped photosensitive area
The p-type impurity ion of arsenic ion projected range head, forms lp1 region, and implantation dosage scope is 2 × 1011cm-2～3 × 1011cm-2, Implantation Energy scope is 650kev～850kev；
Step 4: inject the p-type impurity ion than arsenic ion projected range head below lp1 region, form lp2 region,
Lp1 region and lp2 region form longitudinally annular p-type and buried regions are lightly doped, and produce built in field, and implantation dosage scope is 2 ×
1011cm-2～3 × 1011cm-2, Implantation Energy scope is 1300kev～1600kev；
Step 5: using sn mask blank, arsenic ion implanted with p-type is lightly doped buried regions ring-shaped inner part, forms secondary N-shaped
Photosensitive buried regions, the photosensitive buried regions of secondary N-shaped and p-type are lightly doped buried regions and produce sidewall parasitic capacitance, ultimately form resistance to crosstalk inverted u shape and bury
Layer photodiode.
In described step one, the doping content of p-type epitaxial layer is 1 × 1015cm-3.
The dosage range injecting arsenic ion in described step one is 5 × 1012cm-2～7 × 1012cm-2, Implantation Energy scope
For 60kev～100kev.
In described step 2, the implantation dosage scope of boron ion is 8 × 1012cm-2～1 × 1013cm-2, Implantation Energy scope
For 5kev～8kev.
In described step 3 and step 4 than arsenic ion projected range head p-type impurity ion be nitrogen or phosphorus.
In described step 5, arsenic ion implantation dosage scope is 8 × 1011cm-2～12 × 1011cm-2, Implantation Energy scope is
200kev～300kev.
Compared with prior art, a kind of resistance to crosstalk inverted u shape buried regions photodiode of the present invention has the advantages that
1) present invention does not affect pixel photosensitive area and fill factor, curve factor, does not increase the area of sensor chip yet；
2) injection of the secondary light-sensitive n buried regions of the present invention makes depletion layer extend to substrate further, and incident illumination can be had
The depth that effect absorbs is deeper, therefore has higher long-wave band illumination quantum efficiency；
3) the photosensitive buried regions of secondary N-shaped " being embedded " of the present invention is lightly doped in buried regions in p-type, and being equivalent to is only initial N-shaped
The central region of photosensitive area extends to p-type epitaxial layer, and because impurity concentration gradient be distributed the reason, the photosensitive buried regions of secondary N-shaped
Doping content is relatively low, therefore, it is possible to exhaust ability to a certain degree keep the photosensitive buried regions of initial N-shaped, is not likely to produce former frame letter
Number charge residue to next frame " streaking " phenomenon.
Further, a kind of resistance to crosstalk of present invention inverted u shape buried regions photodiode is noted below initial N-shaped photosensitive area again
Enter the photosensitive buried regions of secondary N-shaped, increased photodiode sidewall parasitic capacitance, and then increase full trap charge capability.
A kind of generation method of present invention resistance to crosstalk inverted u shape buried regions photodiode, is by under initial N-shaped photosensitive area
Inject high-energy low dosage p-type impurity around side and p-type epitaxial layer epitaxial layer intersection, realize mending with the impurity of p-type epitaxial layer
Repay, generate the p-type lower than p-type epitaxial layer concentration and buried regions is lightly doped, and form Concentraton gradient and p-type epitaxial layer between, set up
The built in field that buried regions points to p-type epitaxial layer is lightly doped by p-type, makes to result from epitaxial layer and substrate compared with long-wave band incident illumination
The carrier exciting is subject to the effect of built in field power to drift about and be collected to top layer photosensitive n buried regions, prevents the horizontal of electric charge
Diffusion, electric charge crosstalk phenomenon is inhibited.
Brief description
Fig. 1 is traditional 4t active pixel circuit diagram；
Fig. 2 is traditional ppd structure charge crosstalk mechanism；
Fig. 3 is the present invention two step lightly doped p-type structural representation；
Fig. 4 is that the photosensitive buried regions of the secondary N-shaped of the present invention injects schematic diagram；
Fig. 5 is photosensitive area of the present invention domain schematic diagram.
Specific embodiment
The present invention will be further described below in conjunction with the accompanying drawings.
Referring to Fig. 3, Fig. 4 and Fig. 5, a kind of present invention resistance to crosstalk inverted u shape buried regions photodiode, including p-type epitaxial layer 130
With the p-substrate 200 in its underpart, p-type epitaxial layer 130 top is provided with surface p+clamper layer 100, surface p+clamper layer 100
Bottom is provided with initial N-shaped photosensitive area 110, and the p-type being provided with two-layer annular below initial N-shaped photosensitive area 110 is lightly doped buried regions,
P-type is lightly doped buried regions ring-shaped inner part and is provided with the photosensitive buried regions of secondary N-shaped 410.
Embodiment 1:
Step one: doping content be 1 × 1015cm-3P-type epitaxial layer 130 in injection arsenic ion form initial N-shaped sense
Light area 110, the dosage of injection arsenic ion is 5 × 1012cm-2, Implantation Energy is 60kev；
Step 2: injection boron ion forms p+ clamper layer 100, the implantation dosage of boron ion on initial N-shaped photosensitive area 110
For 8 × 1012cm-2, Implantation Energy is 5kev；
Step 3: below initial N-shaped photosensitive area 110 with epitaxial layer intersection around using lp mask blank 520
Injection phosphonium ion, forms lp1 region 320, and implantation dosage is 2.2 × 1011cm-2～, Implantation Energy is 700kev；
Step 4: injection nitrogen or phosphonium ion below lp1 region 320, form lp2 region 321, lp1 region 320 and lp2
Region 321 forms longitudinally annular p-type and buried regions is lightly doped, and produces built in field, and implantation dosage is 3 × 1011cm-2, Implantation Energy
For 1600kev；
Step 5: arsenic ion 411 implanted with p-type is lightly doped buried regions ring-shaped inner part, arsenic ion 411 using sn mask blank
Implantation dosage is 8 × 1011cm-2, Implantation Energy is 200kev, forms the photosensitive buried regions of secondary N-shaped 410, the photosensitive buried regions of secondary N-shaped
410 are lightly doped buried regions with p-type produces sidewall parasitic capacitance 420, ultimately forms resistance to crosstalk inverted u shape buried regions photodiode.
Embodiment 2:
Step one: doping content be 1 × 1015cm-3P-type epitaxial layer 130 in injection arsenic ion form initial N-shaped sense
Light area 110, the dosage of injection arsenic ion is 5 × 1012cm-2, Implantation Energy is 60kev；
Step 2: the injection boron ion on initial N-shaped photosensitive area 110 forms p+ clamper layer 100, the injectant of boron ion
Measure as 8 × 1012cm-2, Implantation Energy is 5kev；
Step 3: below initial N-shaped photosensitive area 110 with epitaxial layer intersection around using lp mask blank 520
Injection phosphonium ion, forms lp1 region 320, and implantation dosage is 2 × 1011cm-2, Implantation Energy is 650kev；
Step 4: injection nitrogen or phosphonium ion below lp1 region 320, form lp2 region 321, lp1 region 320 and lp2
Region 321 forms longitudinally annular p-type and buried regions is lightly doped, and produces built in field, and implantation dosage is 2 × 1011cm-2, Implantation Energy
For 1300kev；
Step 5: arsenic ion 411 implanted with p-type is lightly doped buried regions ring-shaped inner part, arsenic ion 411 using sn mask blank
Implantation dosage is 8 × 1011cm-2, Implantation Energy is 200kev, forms the photosensitive buried regions of secondary N-shaped 410, the photosensitive buried regions of secondary N-shaped
410 are lightly doped buried regions with p-type produces sidewall parasitic capacitance 420, ultimately forms resistance to crosstalk inverted u shape buried regions photodiode.
Embodiment 3:
Step one: doping content be 1 × 1015cm-3P-type epitaxial layer 130 in injection arsenic ion form initial N-shaped sense
Light area 110, the dosage of injection arsenic ion is 7 × 1012cm-2, Implantation Energy is 100kev；
Step 2: the injection boron ion on initial N-shaped photosensitive area 110 forms p+ clamper layer 100, the injectant of boron ion
Measure as 1 × 1013cm-2, Implantation Energy is 8kev；
Step 3: below initial N-shaped photosensitive area 110 with epitaxial layer intersection around using lp mask blank 520
Injecting nitrogen ion, forms lp1 region 320, and implantation dosage is 3 × 1011cm-2, Implantation Energy is 850kev；
Step 4: injection nitrogen or phosphonium ion below lp1 region 320, form lp2 region 321, lp1 region 320 and lp2
Region 321 forms longitudinally annular p-type and buried regions is lightly doped, and produces built in field, and implantation dosage is 3 × 1011cm-2, Implantation Energy
For 1600kev；
Step 5: arsenic ion 411 implanted with p-type is lightly doped buried regions ring-shaped inner part, arsenic ion 411 using sn mask blank
Implantation dosage is 12 × 1011cm-2, Implantation Energy is 300kev, forms the photosensitive buried regions of secondary N-shaped 410, the photosensitive buried regions of secondary N-shaped
410 are lightly doped buried regions with p-type produces sidewall parasitic capacitance 420, ultimately forms resistance to crosstalk inverted u shape buried regions photodiode.
Embodiment 4:
Step one: doping content be 1 × 1015cm-3P-type epitaxial layer 130 in injection arsenic ion form initial N-shaped sense
Light area 110, the dosage of injection arsenic ion is 6 × 1012cm-2, Implantation Energy is 80kev；
Step 2: the injection boron ion on initial N-shaped photosensitive area 110 forms p+ clamper layer 100, the injectant of boron ion
Measure as 9 × 1012cm-2, Implantation Energy is 7kev；
Step 3: below initial N-shaped photosensitive area 110 with epitaxial layer intersection around using lp mask blank 520
Injection phosphonium ion, forms lp1 region 320, and implantation dosage is 1.5 × 1011cm-2, Implantation Energy is 750kev；
Step 4: injection nitrogen or phosphonium ion below lp1 region 320, form lp2 region 321, lp1 region 320 and lp2
Region 321 forms longitudinally annular p-type and buried regions is lightly doped, and produces built in field, and implantation dosage is 1.5 × 1011cm-2, inject energy
Measure as 1450kev；
Step 5: arsenic ion 411 implanted with p-type is lightly doped buried regions ring-shaped inner part, arsenic ion 411 using sn mask blank
Implantation dosage is 10 × 1011cm-2, Implantation Energy is 150kev, forms the photosensitive buried regions of secondary N-shaped 410, the photosensitive buried regions of secondary N-shaped
410 are lightly doped buried regions with p-type produces sidewall parasitic capacitance 420, ultimately forms resistance to crosstalk inverted u shape buried regions photodiode.
The present invention passes through compromise and considers the suppression of crosstalk effect and the holding of other main pixel performance indications and improvement, does
Following two step structures are improved: step one is to distinguish around initial N-shaped photosensitive area (on) 110 lower section with epitaxial layer intersection
The longitudinal p-type of injection is lightly doped buried structure；Step 2 is to be lightly doped between buried regions in p-type to inject the photosensitive buried regions of secondary N-shaped, with p
Type is lightly doped buried regions and forms inverted u shape structure.
As shown in figure 3, being lightly doped in the generation method of buried regions it is desirable to new implanted with p-type concentration will be less than p-type extension in p-type
The doping content of layer, therefore needs according to impurity compensation principle, and the different p-type impurity ion 311 of Implantation Energy is compensating p in two steps
Acceptor ion in type epitaxial layer, two step injection mask plates are identical.The selection of this N-shaped ionic type must be that atomic number is less than
The ion of initial n buried regions impurity, to obtain deeper projected range.First step implantation dosage is 2 × 1011cm-2～3 ×
1011cm-2, energy is 650kev～850kev, forms lp1 region；Second step implantation dosage is 2 × 1011cm-2～3 × 1011cm-2, energy is 1300kev～1600kev, forms lp2 region, then lp1 and lp2 buried regions is formed such that outside lp region with p-type
Prolong to establish between layer 130 and the deep layer electric field 330 that buried regions points to p-type epitaxial layer is lightly doped by p-type, its electric field intensity can be expressed
For:
Wherein, k0For Boltzmann constant；T is temperature；Q is the unit quantity of electric charge；nepiAnd nlpIt is respectively p-type epitaxial layer and p
Type is lightly doped the doping content of buried regions；zhlWidth for newly-built electric field action zone.This electric field is to result from 130 in p-type epitaxial layer
Photo-generated carrier 240 provide steady electric field power so as to drift the quick uptake zone of light echo, thus reduce surplus photo-generated carrier
240 horizontal proliferation to neighbor uptake zone probability it is suppressed that electric charge crosstalk.In addition, result from the minority of substrate 200 not by
The electric field 331 effect drift that compound photo-generated carrier 250 also can be produced by the Concentraton gradient of epitaxial layer and substrate formation
Return in epitaxial layer and absorbed by photosensitive area.
It should be noted that from formula (1), lower lp doping content can make newly-built electric field stronger, to electric charge string
The inhibitory action disturbed is also bigger, but when lp doping content is sufficiently low and reaches transoid critical point, this area epitaxy layer is possible to
Transoid is N-shaped, causes unnecessary initial n buried regions extension and the ability that exhausts weak, leads to n buried regions pinch-off voltage to raise, unfavorable
Shift completely in electric charge, easily cause streaking phenomenon.Therefore, lp region transoid should not become N-shaped.
As shown in Figure 4 and Figure 5, in the generation method of the photosensitive buried regions of secondary N-shaped, using a higher-energy N-shaped from
Son injection 411, this ionic type and initial n buried regions 110 impurities phase are with its mask plate photoetching window ranges is located at the interior of lp region
Portion, and with lp mask plate inside window edge keep apart certain distance 510 it is therefore an objective to the impurity horizontal proliferation that formed for deep injection
Reserved location, reduces secondary n buried regions 410 and lp region impurity compensation effect.The injection of secondary n buried regions 410 makes initial n buried regions
Extended, created the sidewall parasitic capacitance 420 between secondary n buried regions 410 as shown in Figure 4 and lp, extend full trap and hold
Amount.And the extension of initial n buried regions also makes depletion region 210 extension 211 below secondary n buried regions 410 so that photoproduction current-carrying
Son drift collected volume expands, and medium-long wave band illumination quantum efficiency is effectively lifted.
It should be noted that in 4t dot structure, signal charge quantity can only be determined by reading the quantity of electric charge of fd point,
The maximum amount of charge that therefore effectively full-well capacity can should receive for fd point, this just involves electric charge and is transferred to fd by ppd
Transfer efficiency problem, transfer efficiency is bigger, can be bigger by the signal swing of effectively reading.So secondary n buried regions 410 area
The doping content in domain need to be as far as possible low, and should not be extended down to too deep, exhausts ability with keep whole n region, is unlikely to make pinch off
Voltage raises and leads to charge transfer effciency to reduce.Therefore, sn implantation dosage is chosen as 8 × 1011cm-2～12 × 1011cm-2, note
Enter energy and be chosen as 200kev～300kev.
Claims (7)
1. a kind of generation method of resistance to crosstalk inverted u shape buried regions photodiode it is characterised in that: comprise the following steps:
Step one: injection arsenic ion forms initial N-shaped photosensitive area (110) in p-type epitaxial layer (130)；
Step 2: the injection boron ion on initial N-shaped photosensitive area (110) forms p+ clamper layer (100)；
Step 3: below initial N-shaped photosensitive area (110) with epitaxial layer intersection around using lp mask blank (520)
Injection, than the p-type impurity ion of arsenic ion projected range head, forms lp1 region (320), and implantation dosage scope is 2 × 1011cm-2
～3 × 1011cm-2, Implantation Energy scope is 650kev～850kev；
Step 4: inject the p-type impurity ion than arsenic ion projected range head below lp1 region (320), form lp2 region
(321), lp1 region (320) and lp2 region (321) form longitudinally annular p-type and buried regions are lightly doped, and produce built in field, injection
Dosage range is 2 × 1011cm-2～3 × 1011cm-2, Implantation Energy scope is 1300kev～1600kev；
Step 5: using sn mask blank, arsenic ion (411) implanted with p-type is lightly doped buried regions ring-shaped inner part, forms secondary N-shaped
Photosensitive buried regions (410), the photosensitive buried regions (410) of secondary N-shaped and p-type are lightly doped buried regions and produce sidewall parasitic capacitance (420), end form
Become resistance to crosstalk inverted u shape buried regions photodiode.
2. a kind of resistance to crosstalk inverted u shape buried regions photodiode according to claim 1 generation method it is characterised in that:
In described step one, the doping content of p-type epitaxial layer (130) is 1 × 1015cm-3.
3. a kind of resistance to crosstalk inverted u shape buried regions photodiode according to claim 2 generation method it is characterised in that:
The dosage range injecting arsenic ion in described step one is 5 × 1012cm-2～7 × 1012cm-2, Implantation Energy scope be 60kev～
100kev.
4. a kind of resistance to crosstalk inverted u shape buried regions photodiode according to claim 2 generation method it is characterised in that:
In described step 2, the implantation dosage scope of boron ion is 8 × 1012cm-2～1 × 1013cm-2, Implantation Energy scope be 5kev～
8kev.
5. a kind of resistance to crosstalk inverted u shape buried regions photodiode according to claim 2 generation method it is characterised in that:
In described step 3 and step 4 than arsenic ion projected range head p-type impurity ion be nitrogen or phosphorus.
6. a kind of resistance to crosstalk inverted u shape buried regions photodiode according to claim 2 generation method it is characterised in that:
In described step 5, arsenic ion (411) implantation dosage scope is 8 × 1011cm-2～12 × 1011cm-2, Implantation Energy scope is
200kev～300kev.
7. a kind of resistance to crosstalk inverted u shape buried regions photoelectricity two pole being generated according to the generation method of any one in claim 1 to 6
Pipe it is characterised in that: include p-type epitaxial layer (130) and the p-substrate (200) in its underpart, p-type epitaxial layer (130) top sets
It is equipped with surface p+clamper layer (100), surface p+clamper layer (100) bottom is provided with initial N-shaped photosensitive area (110), initial N-shaped sense
The p-type being provided with two-layer annular below light area (110) is lightly doped buried regions, and p-type is lightly doped buried regions ring-shaped inner part and is provided with secondary N-shaped
Photosensitive buried regions (410).
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| CN201410353580.2A CN104112782B (en) | 2014-07-23 | 2014-07-23 | Anti-crosstalk reverse-U-shaped buried layer photodiode and generation method |
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