WO2019185376A1 - Réseau de détecteurs de rayonnement de rayons x à points quantiques présentant une efficacité de collecte et/ou une efficacité de détection de charge améliorée - Google Patents

Réseau de détecteurs de rayonnement de rayons x à points quantiques présentant une efficacité de collecte et/ou une efficacité de détection de charge améliorée Download PDF

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Publication number
WO2019185376A1
WO2019185376A1 PCT/EP2019/056633 EP2019056633W WO2019185376A1 WO 2019185376 A1 WO2019185376 A1 WO 2019185376A1 EP 2019056633 W EP2019056633 W EP 2019056633W WO 2019185376 A1 WO2019185376 A1 WO 2019185376A1
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WIPO (PCT)
Prior art keywords
electrically conductive
porous silicon
quantum dot
silicon
detector array
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Ceased
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PCT/EP2019/056633
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English (en)
Inventor
Marc Anthony CHAPPO
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Koninklijke Philips NV
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Koninklijke Philips NV
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Publication of WO2019185376A1 publication Critical patent/WO2019185376A1/fr
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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/20—Measuring radiation intensity with scintillation detectors
    • G01T1/208—Circuits specially adapted for scintillation detectors, e.g. for the photo-multiplier section
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01T—MEASUREMENT OF NUCLEAR OR X-RADIATION
    • G01T1/00—Measuring X-radiation, gamma radiation, corpuscular radiation, or cosmic radiation
    • G01T1/16—Measuring radiation intensity
    • G01T1/24—Measuring radiation intensity with semiconductor detectors
    • G01T1/247—Detector read-out circuitry

Definitions

  • the following generally relates to imaging and more particular to a quantum dot (QD) X-ray radiation detector array with improved charge collection efficiency and/or detection efficiency, and is described with particular application to computed tomography (CT) imaging.
  • QD quantum dot
  • CT computed tomography
  • a quantum dot (QD) X-ray radiation detector array includes a plurality of modules.
  • Each of the modules includes a plurality of porous Silicon (pSi) quantum dot (QD) pixels (pSi-QD pixels).
  • pSi-QD pixels includes a pSi structure with a plurality of columns of Si interleaved with a plurality of pores filled with QD’s, a non-porous solid block of Si under the pSi membrane, and a bottom contact under the non-porous solid block of Si.
  • a layer of QD’s extends over the pSi membranes, a top bias layer extends over the layer of QD’s, and a substrate extends under the bottom contacts.
  • Each of the bottom contacts is an electrically conductive pad on a bottom surface of the non-porous solid block of Si that is configured to collect electrical charge created in the pSi structure.
  • the non-porous solid block of Si between the pores and the bottom contact limits charge collection of carries present in the Si by the electrically conductive pad, reducing charge collection efficiency. Charge collection diminishes as the distance between the QD’s in the pores and the electrically conductive pad is increased, and, hence a greater thickness of the non-porous solid block of Si challenges efficiency.
  • the top bias layer includes an electrically conductive material.
  • a wire or the like is electrically connected to the top bias layer, routed around an edge of the module, and electrically connected to circuitry of the substrate.
  • this wire increases the effective width of the module, which increases a distance between neighboring modules, which reduces detection efficiency.
  • the wire also increases overall detector array cost.
  • a radiation sensitive detector array of an imaging system includes a first detector pixel.
  • the first detector pixel includes a first bottom contact and a first porous silicon structure.
  • the first porous silicon structure includes a first plurality of columns of silicon.
  • the first porous silicon structure further includes a first plurality of pores with first quantum dots interlaced with the first plurality of columns of silicon.
  • the first porous silicon structure further includes first bulk silicon below the first plurality of columns of silicon and the first plurality of pores.
  • the first bulk silicon is adjacent to the bottom contact.
  • the first porous silicon structure further includes a first electrically conductive via integrated in the first bulk silicon adjacent to at least one of the first plurality of pores with the first quantum dots and in electrical communication with the first bottom contact.
  • a radiation sensitive detector array of an imaging system includes a first module with a first porous silicon quantum dot detector pixel and a second porous silicon quantum dot detector pixel.
  • the first porous silicon quantum dot detector pixel includes a first porous silicon structure, a first bottom contact, and first bulk silicon between the first porous silicon structure and the first bottom contact.
  • the second porous silicon quantum dot detector pixel includes a second porous silicon structure, a second bottom contact, and second bulk silicon between the second porous silicon structure and the second bottom contact.
  • the first module further includes a layer of quantum dots adjacent to the first and second porous silicon structures, a top contact adjacent to the layer of quantum dots, a substrate adjacent to the first and second bottom contacts, and an electrically conductive pathway in the interstice between the top contact to the substrate.
  • a computed tomography imaging system in another aspect, includes a radiation source configured to emit X-ray radiation, a detector array configured to detect X-ray radiation and generate an electrical signal indicative thereof.
  • the detector array includes a plurality of radiation detector modules. Each module includes a first porous silicon quantum dot detector pixel, a second porous silicon quantum dot detector pixel, a first electrically conductive via integrated in the first porous silicon quantum dot detector pixel and configured to collect and route first charge produced in the first porous silicon quantum dot detector pixel, and a second electrically conductive via integrated in the second porous silicon quantum dot detector pixel and configured to collect and route second charge produced in the second porous silicon quantum dot detector pixel.
  • Each module further includes a top contact common to both the first porous silicon quantum dot detector pixel and the second porous silicon quantum dot detector pixel, a substrate common to both the first porous silicon quantum dot detector pixel and the second porous silicon quantum dot detector pixel, and an electrically conductive pathway electrically connecting the top contact and the top substrate.
  • the invention may take form in various components and arrangements of components, and in various steps and arrangements of steps.
  • the drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention.
  • FIGURE 1 schematically illustrates an example CT imaging system with a pSi-QD X-ray radiation detector array, in accordance with an embodiment(s) herein.
  • FIGURE 2 schematically illustrates an example pSi-QD pixel of the array with an electrically conductive via integrated in a Si bulk portion of a pSi structure, in accordance with an embodiment(s) herein.
  • FIGURE 3 schematically illustrates a sub-portion of an example module of the array with an electrically conductive pathway from a common top contact to a common substrate, in accordance with an embodiment(s) herein.
  • FIGURE 4 schematically illustrates an example the electrically conductive pathway of FIGURE 3, in accordance with an embodiment(s) herein.
  • FIGURE 5 schematically illustrates another example the electrically conductive pathway of FIGURE 3, in accordance with an embodiment(s) herein.
  • FIGURE 6 schematically illustrates yet another example the electrically conductive pathway of FIGURE 3, in accordance with an embodiment(s) herein.
  • FIGURE 7 schematically illustrates a combination of the examples described in connection with FIGURES 2 and 3.
  • FIGURE 8 illustrates an example method in accordance with an embodiment(s) herein
  • FIGURE 9 schematically illustrates a variation of the pSi-QD pixel of FIGURE 2 that includes an insulator between the top contact and the pSi structure.
  • FIGURE 1 schematically illustrates an example imaging system 100 such as a computed tomography (CT) system configured for spectral and/or non-spectral imaging.
  • the imaging system 100 includes a stationary gantry 102 and a rotating gantry 104, which is rotatably supported by the stationary gantry 102.
  • the rotating gantry 104 rotates around an examination region 106 about a longitudinal or z-axis 108.
  • a radiation source 110 such as an x-ray tube, is supported by the rotating gantry 104, rotates therewith, and generates and emits X-ray radiation.
  • a radiation sensitive detector array 112 includes one or more rows arranged parallel to each other along the z-axis 108 direction, each row including a plurality of detector modules 114 extending transverse to the z-axis 108 direction.
  • the modules 114 include detector pixels that detect X-ray radiation traversing the examination region 106 and generate electrical signals (projection data) indicative thereof.
  • At least one of the detector pixels includes an electrically conductive top contact 116, an electrically conductive bottom contact 118, a pSi structure 120 with QD nanoparticles 122, and a substrate 128.
  • the pSi structure 120 includes an electrically conductive via 124, which improves charge collection efficiency, relative to configuration without the via 124, e.g., by reducing a distance between the bottom contact 118 and the QD’s 122.
  • the pSi structure 120 includes an electrically conductive pathway (ECP) 126 that extends entirely through the pSi structure 120 from the top contact 116 to the substrate 128, which improves detection efficiency by mitigating an external wire from the top contact 116, around the module 114, and to the substrate 128.
  • ECP electrically conductive pathway
  • a subject support 130 such as a couch, supports an object or subject in the examination region 106.
  • a reconstructor 132 reconstructs the electrical signals with one or more reconstruction algorithms.
  • a computing system serves as an operator console 134 and includes a display, an input device such as a keyboard, mouse, and/or the like, one or more processors and computer readable storage medium. Software resident on the console 134 allows an operator to control an operation of the imaging system 100.
  • FIGURE 2 schematically illustrates an example of a pixel 200 of the module
  • the pSi structure 120 includes a plurality of columns of Si 202 interleaved with a plurality pores 204 filled with the QD’s 122.
  • the pSi structure 120 further includes a layer 206 of the QD’s 122 over the plurality of columns of Si 202 and the plurality pores 204 including ones with the QD’s 122.
  • the pSi structure 120 further includes a block of Si material 208 below the plurality of columns of Si 202 and the plurality pores 204 with the QD’s 122.
  • the top contact 116 includes an electrically conductive material and is disposed one a top side 210 of the pSi membrane 120 adjacent to the layer 206 of the QD’s 122.
  • the top contact 116 is affixed to the top side 210 of the pSi membrane 120 through solder and/or an adhesive such as a glue.
  • the top contact 210 may be isolated from direct contact with the QD’s 122 with an insulator 902 such as a silicon dioxide (Si0 2 ) deposition or similar insulator, as schematically illustrated in FIGURE 9.
  • the bottom contact 118 includes an electrically conductive material and is disposed on a bottom side 212 of the pSi structure 120 adjacent to the block of Si material 208 and the substrate 214.
  • the bottom contact 118 is affixed to the bottom side 212 through solder and/or an adhesive such as a glue.
  • the at least electrically conductive via 124 is in the block of Si 208 material and is electrically connected to the bottom contact 118.
  • the electrically conductive via 124 is separated from at least one of the pores 204 with the QD’s 122 by a first distance 216
  • the bottom contact 118 is separated from the at least one of the pores 204 with the QD’s 122 by a second distance 218, and the first distance 216 is less than the second distance 218.
  • the first distance 216 is as small as practical.
  • the at least electrically conductive via 124 by being closer to the pores 204 with the QD’s 122 than the bottom contact 118, allows for collecting carriers closer to the point at which they are generated, i.e., near the boundary of the pores 204 with the QD’s 122 and the block of Si material 208. In general, charge collection efficiency increases as the first distance decreases. As such, the at least electrically conductive via 124 improves charge collection efficiency, relative to a configuration in which the at least electrically conductive via 124 is omitted.
  • the at least one electrically conductive via 124 is created in the fabrication of the pSi structure using known processes for vias in Si.
  • the at least one electrically conductive via 124 creates connections that are small in dimension but provide for more efficient charge collection relative to the bottom contact 118 located below the block of Si material 208.
  • a detector module with the pixel 200 can be fabricated in the same manner as existing detectors and utilized in a CT scanner or other radiation detection applications.
  • FIGURE 3 schematically illustrates a sub-portion of an example of the module
  • the module 114 includes a plurality of pSi-based pixels, such as the pixel 200 of FIGURE 2 without the via 124 (shown here), the pixel 200 of FIGURE 2 with the via 124 (as described in connection with FIGURE 7), and/or other pSi-based pixel.
  • pSi-based pixels such as the pixel 200 of FIGURE 2 without the via 124 (shown here), the pixel 200 of FIGURE 2 with the via 124 (as described in connection with FIGURE 7), and/or other pSi-based pixel.
  • the illustrated sub-portion of module 114 includes the pixel 200 of FIGURE 2 without the via 124, a neighboring second pixel 200’ (which is substantially similar to the pixel 200), and an interstice 302 therebetween.
  • the neighboring second pixel 200’ includes a pSi structure 120’ with a plurality of columns of Si 202’ interleaved with a plurality pores (not shown) with the QD’s 122 similar to the pSi structure 120.
  • the neighboring second pixel 200’ further includes a bottom contact 118’ under the pSi structure 120’ similar to the bottom contact 118 under the pSi structure 120.
  • the top contact 116 extends over both the pixel 200 and the pixel 200’, and the substrate 214 extends below both the pixel 200 and the pixel 200’.
  • the top layer 206 of QD’s 118 also extends over both the pixel 200 and the pixel 200’.
  • the layer 206 includes a hole 304 in a sub-portion of the layer 206 in the interstice 302. The hole 304 is above a space 306 between Si columns of the pixel 200 and the neighboring pixel 200’.
  • the bottom contact 118 extends partially into the interstice 302, the bottom contact 118’ extends partially into the interstice 302, and there is a gap 308 therebetween.
  • at least one of the bottom contact 118 and/or 118’ extends only up to a border of the interstice 302 or terminates before the border of the interstice 302.
  • the gap 308 includes an electrical insulator 310.
  • the electrical insulator 310 includes a hole 312, which is below the space 306 between Si columns of the pixel 200 and the neighboring pixel 200’.
  • the hole 304 in the layer 206, the space 306 between Si columns of the pixel 200 and the neighboring pixel 200’, and the hole 312 in the electrical insulator 310 is filled with an electrically conductive material (e.g., electrically conductive QD’s and/or other material), which extends entirely between the top contact 116 and the substrate 214, providing an electrically conductive pathway 314 from the top contact 116 to the substrate 214.
  • This electrically conductive pathway 314 mitigates using external wire(s) to electrically connect the top contact 116 to the substrate 128.
  • the module 114 includes a single electrically conductive pathway 314. In a variation, the module 114 includes two or more electrically conductive pathways 314. The two or more electrically conductive pathways 314 can be next to a same pixel or different pixels. In the illustrated example, the electrically conductive pathway 314 is between pixels 200 and 200’. In a variation, the electrically conductive pathway 314 is in a boundary region between the pixel 200 or the pixel 200’ and an edge of the module 300.
  • FIGURES 4, 5 and 6 illustrate top down views of the electrically conductive pathway 314 along a line A- A of FIGURE 3.
  • the electrically conductive pathway 314 (shown with a cross hatch pattern) includes or is surrounded with an electrical insulator 402 (e.g., an oxide).
  • the electrical insulator 402 provides electrical insulation between the electrically conductive pathway 314 and one or more of the layer 206, the pSi 120, the pSi 120’, the bottom contact 118, and/or the bottom contact 118’.
  • the electrically conductive pathway 314 is shown cylindrical in shape. However, it is to be understood that the electrically conductive pathway 314 can be otherwise shaped.
  • the electrically conductive pathway 314 (shown with a cross hatch pattern) is surrounded by a plurality of empty holes 502 (shown with white interiors).
  • the plurality of empty holes 502 electrically insulate the electrically conductive pathway 314 from one or more of the layer 206, the pSi 120, the pSi 120’, the bottom contact 118, and/or the bottom contact 118’.
  • the electrically conductive pathway 314 is centrally located within the plurality of empty holes 502. In a variation, the electrically conductive pathway 314 is otherwise located and not centrally located within the plurality of empty holes 502.
  • the electrically conductive pathway 314 (shown with a cross hatch pattern) is surrounded by a plurality of holes 602 including electrically insulative QD’s 604 (shown with a dotted pattern).
  • the electrically insulative QD’s 604 electrically insulate the electrically conductive pathway 314 from one or more of the layer 206, the pSi 120, the pSi 120’, the bottom contact 118, and/or the bottom contact 118’.
  • the electrically conductive pathway 314 is centrally located within the plurality of holes 602 with the QD’s 604.
  • the electrically conductive pathway 314 is otherwise located and not centrally located within the plurality of holes 602 with the QD’s 604.
  • FIGURE 7 schematically illustrates a combination of the embodiments described in connection with FIGURES 2 and 3 and includes both the via 124 in the pixel 200 and the electrically conductive pathway 314 in the interstice 302 between the pixel 200 and the pixel 200’.
  • a module e.g., the module 114 includes a two- dimensional (2-D) matrix of the pixels 200 and 200’.
  • Each pixel of the matrix includes one or more of the vias 124
  • the module 114 includes one or more of the electrically conductive pathways 314.
  • each of the sides of the modules can abut another module (e.g., four-side buttable). This configuration provides a module with greater charge collection and detection efficiency relative to a configuration without the vias 124 and the electrically conductive pathways 314.
  • the following provides a non-limiting example of creating the electrically conductive pathways 314.
  • masks are generated to deposit conductive nanoparticles (QD’s) into pores to a height above the pores that matches that of the QD semiconductor to be deposited in a subsequent step.
  • a conductive member could be placed in contact with the via in the pores to extend the height of the via to accommodate a final height of the QD material deposition.
  • the bias layer of conductive material e.g., a thin sheet
  • a Si0 2 deposition is made before the top layer is placed as such. This provides a bias connection to the top through the pSi structure.
  • a detector module is the fabricated with a bias contact matching the detector footprint and no external wire to the bias layer is required.
  • FIGURE 8 illustrates an example method in accordance with an embodiment(s) herein
  • a pixel of a pSi-QD module absorbs X-ray radiation and produces charge through an interaction between columns of QD’s and columns of Si / bulk Si.
  • a via protruding into bulk Si and a bottom contact below the bulk Si collect the charge.
  • the collected charge is routed to a substrate through the pSi structure of the module.
  • the substrate routes the collected charge (and/or processed charge) off the pSi-QD detector.
  • the collected charge is processed to create an image.
  • the via is omitted and the charge is collected by the bottom contact.
  • the collected charge is routed to the substrate with an external wire and not through the pSi.
  • the word“comprising” does not exclude other elements or steps, and the indefinite article“a” or“an” does not exclude a plurality.
  • a single processor or other unit may fulfill the functions of several items recited in the claims.
  • the mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measured cannot be used to advantage.
  • a computer program may be stored/distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms, such as via the Internet or other wired or wireless telecommunication systems. Any reference signs in the claims should not be construed as limiting the scope.

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  • Physics & Mathematics (AREA)
  • Health & Medical Sciences (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • General Physics & Mathematics (AREA)
  • High Energy & Nuclear Physics (AREA)
  • Molecular Biology (AREA)
  • Spectroscopy & Molecular Physics (AREA)
  • Solid State Image Pick-Up Elements (AREA)

Abstract

L'invention concerne un réseau de détecteurs sensible au rayonnement (112) d'un système d'imagerie (100) incluant un premier pixel de détecteur (200). Le premier pixel de détecteur inclut un premier contact inférieur (118) et une première structure de silicium poreux (120). La première structure de silicium poreux inclut une première pluralité de colonnes de silicium (202). La première structure de silicium poreux inclut en outre une première pluralité de pores (204) présentant des premiers points quantiques (122) entrelacés avec la première pluralité de colonnes de silicium. La première structure de silicium poreux inclut un premier silicium massif (208) sous la première pluralité de colonnes de silicium et la première pluralité de pores. Le premier silicium massif est adjacent au contact inférieur. La première structure de silicium poreux inclut en outre un premier trou d'interconnexion électriquement conducteur (124) intégré dans le premier silicium massif adjacent à au moins l'un de la première pluralité de pores présentant les premiers points quantiques et en communication électrique avec le premier contact inférieur.
PCT/EP2019/056633 2018-03-29 2019-03-15 Réseau de détecteurs de rayonnement de rayons x à points quantiques présentant une efficacité de collecte et/ou une efficacité de détection de charge améliorée Ceased WO2019185376A1 (fr)

Applications Claiming Priority (2)

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US201862649636P 2018-03-29 2018-03-29
US62/649636 2018-03-29

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WO2019185376A1 true WO2019185376A1 (fr) 2019-10-03

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Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120175584A1 (en) * 2008-01-14 2012-07-12 Weinberg Medical Physics Llc Structures for radiation detection and energy conversion using quantum dots
WO2017025888A1 (fr) * 2015-08-07 2017-02-16 Koninklijke Philips N.V. Détecteur d'imagerie à base de points quantiques
WO2018024681A1 (fr) * 2016-08-03 2018-02-08 Koninklijke Philips N.V. Photodétecteur tridimensionnel d'imagerie à semi-conducteur

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20120175584A1 (en) * 2008-01-14 2012-07-12 Weinberg Medical Physics Llc Structures for radiation detection and energy conversion using quantum dots
WO2017025888A1 (fr) * 2015-08-07 2017-02-16 Koninklijke Philips N.V. Détecteur d'imagerie à base de points quantiques
WO2018024681A1 (fr) * 2016-08-03 2018-02-08 Koninklijke Philips N.V. Photodétecteur tridimensionnel d'imagerie à semi-conducteur

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