Medical imaging detectors

Abstract

SOLUTION: Systems and methods are provided for a detector for medical imaging. The detector for medical imaging includes a mesh detector element formed on a planar side of a first semiconductor layer. The mesh detector element includes a metal layer including a plurality of longitudinal strips, where each longitudinal strip is positioned over each second semiconductor layer of an opposite doping polarity from the first semiconductor layer, and embedded in the first semiconductor layer. Further, each longitudinal strip is separated from a neighboring longitudinal strip by each opening of a plurality of openings, such that the metal layer does not extend continuously across a width of the mesh detector element.EFFECT: Images may be reconstructed to have higher resolution and less noise.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] FIELD OF THE INVENTION Embodiments of the subject matter disclosed herein relate to medical imaging, and more particularly to detectors for medical imaging. [Background technology]

[0002] In a computed tomography (CT) imaging system, a cathode generates a beam of electrons, which are directed toward a target in an x-ray tube. The electrons strike the target, producing a fan- or cone-shaped beam of x-rays that are directed toward an object (such as a patient). After being attenuated by the object, the x-rays strike an array of radiation detectors, producing an image.

[0003] The quality of CT images can be improved by using photon-counting CT (PCCT). In PCCT, the radiation detector is a photon-counting detector, which counts photons to provide spectral information. PCCT uses a direct-conversion detector, which offers several advantages over traditional energy-integrated detector (EID) CT systems that use indirect-conversion detectors. However, one of the factors limiting the performance of PCCT detectors is the electronic noise present during imaging. Electronic noise determines the noise floor of the PCCT detector, which is the lowest energy x-ray recorded by the readout electronics. Summary of the Invention

[0004] The present disclosure addresses at least in part one or more of the above-identified problems with a medical imaging detector. The medical imaging detector includes a mesh detector element formed on a planar surface of a first semiconductor layer. The mesh detector element includes a metal layer including a plurality of longitudinal strips, each longitudinal strip disposed on a respective second semiconductor layer of opposite doping polarity to the first semiconductor layer, the second semiconductor layer being embedded in the first semiconductor layer. Further, each longitudinal strip is separated from adjacent longitudinal strips by a respective opening of a plurality of openings, and the metal layer does not extend continuously across the width of the mesh detector element.

[0005] The use of mesh detector elements containing apertures reduces the capacitance of the detector element, which is the largest contributor to electronic noise in PCCT. Furthermore, the use of apertures in the detector elements increases the contrast-to-noise ratio for soft-tissue contrast imaging by 10–15%, while maintaining or slightly increasing the contrast-to-noise ratio for material-decomposition imaging.

[0006] These and other advantages, as well as features of the present description, will be readily apparent from a reading of the Detailed Description alone or in conjunction with the accompanying drawings. It should be understood that the foregoing Summary is provided to introduce a selection of concepts in a simplified form that are further described in the Detailed Description. It is not intended to identify key features or essential features of the claimed subject matter, the scope of which is defined independently by the claims that follow the Detailed Description. Moreover, the claimed subject matter is not limited to implementations that solve the above-described shortcomings or shortcomings noted in any part of this disclosure. [Brief explanation of the drawings]

[0007] The various aspects of the present disclosure can be better understood by reading the following detailed description and by referring to the drawings, in which: [Figure 1]1 shows a diagram of an imaging system in accordance with one or more embodiments of the present disclosure. [Figure 2] 1 shows a block schematic diagram of an exemplary imaging system in accordance with one or more embodiments of the present disclosure. [Figure 3] 1 illustrates a mesh detector element including longitudinal strips and openings in accordance with one or more embodiments of the present disclosure. [Figure 4] 4 illustrates a portion of the mesh detector element of FIG. 3 in accordance with one or more embodiments of the present disclosure. [Figure 5] 4 illustrates a cross-sectional view of the mesh detector element of FIG. 3 disposed on a semiconductor layer in accordance with one or more embodiments of the present disclosure. [Figure 6] 6 shows an expanded view of the cross-sectional view of FIG. 5 in accordance with one or more embodiments of the present disclosure. [Figure 7] 1 illustrates a portion of a first exemplary detector array including mesh detector elements, in accordance with one or more embodiments of the present disclosure. [Figure 8] 10 illustrates a portion of a second exemplary detector array including mesh detector elements, in accordance with one or more embodiments of the present disclosure. [Figure 9] 10 illustrates a third exemplary detector array in accordance with one or more embodiments of the present disclosure. [Figure 10] 10 illustrates a portion of the detector array of FIG. 9 in accordance with one or more embodiments of the present disclosure.

[0008] The drawings illustrate certain aspects of the described systems and methods. The drawings, together with the following detailed description, illustrate and explain the structures, methods, and principles described herein. In the drawings, the size of elements may be exaggerated or otherwise modified for clarity. Well-known structures, materials, or operations have not been shown or described in detail to avoid obscuring aspects of the described elements, systems, and methods. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present description and embodiments of the subject matter disclosed herein relate to methods and systems for reducing capacitance in photon-counting computed tomography (PCCT) systems. Typically, in a computed tomography (CT) imaging system, an X-ray source emits a fan beam or a cone beam toward an object (such as a patient). Generally, in a CT system, the X-ray source and detector array rotate in a gantry within an imaging plane and around the patient, and an image is generated from projection data of multiple views at different view angles. For example, one rotation of the X-ray source generates 1000 views by the CT system. The X-ray beam, after being attenuated by the patient, impinges on an array of radiation detectors. Each X-ray detector or detector array typically includes a collimator for collimating the X-ray beam received by the detector, a scintillator positioned adjacent to the collimator for converting X-rays into light energy, and a photodiode for receiving the light energy from the adjacent scintillator and generating an electrical signal from the received light energy. The intensity of the attenuated beam radiation received at the detector array typically depends on the attenuation of the x-ray beam by the patient. Each detector element of the detector array produces a separate electrical signal indicative of the attenuated beam received by each detector element. The electrical signals are transmitted to a data processing system for analysis. The data processing system processes the electrical signals to generate an image.

[0010] Such conventional CT imaging systems utilize detectors that convert x-ray energy into a time-integrated current signal, which is then measured and ultimately digitized. However, a drawback of such detectors is their inability to provide data regarding the number and / or energy of detected photons. That is, the light emitted by a scintillator is a function of both the number of impinging x-rays and the energy level of the x-rays. Photodiodes cannot distinguish between the energy levels and the number of photons from scintillation. For example, two scintillators may be illuminated with equal intensity, resulting in equal outputs for each photodiode. However, despite the equal light output, the number of x-rays received by each scintillator may be different, and the intensities of the x-rays may differ.

[0011] In contrast, PCCT detectors can provide photon counting and / or energy discriminating feedback with high spatial resolution. PCCT detectors can operate in X-ray counting mode, energy measurement mode for each X-ray event, or both modes. While several materials can be used in the construction of hybrid photon counting energy discriminating detectors, semiconductors have been shown to be one of the preferred materials. Typical materials for such applications include cadmium zinc telluride (CZT), cadmium telluride (CdTe), and silicon (Si). Other heavy semiconductors, such as thallium bromide (TlBr) and mercury iodide (HgI), can also be used.

[0012] PCCT detectors support both x-ray photon counting and energy measurement or tagging, supporting the acquisition of both anatomical details and tissue characteristic information. In this regard, energy discrimination information or data can be used to reduce effects such as beam hardening. Furthermore, PCCT detectors support the acquisition of tissue discrimination data, thereby providing diagnostic information indicative of disease or other pathology. PCCT detectors can also be used to detect, measure, and characterize materials (e.g., contrast agents and / or other special materials) that may be injected into a subject by using optimal energy weighting to enhance the contrast of iodine and calcium (and other high atomic number materials). Contrast agents include, for example, iodine injected into the blood for visualization.

[0013] However, one of the factors limiting the performance of PCCT detectors, especially edge-illuminated silicon-based detectors, is the electronic noise present during imaging. Electronic noise determines the noise floor of a PCCT detector, which is the minimum energy x-ray that can be recorded by the readout electronics. The detector capacitance within a PCCT detector is the largest factor affecting electronic noise, so reducing the detector capacitance reduces the detector's noise floor. In some cases, the detector capacitance can be reduced by forming openings in the detector's interior region, while the remaining strip-like structure continues to generate substantially the same signal from x-rays absorbed in the detector's silicon. Such detectors effectively increase the efficiency of silicon PCCT diodes by reducing electronic noise in the detector's readout electronics and minimizing the photon counting threshold as much as possible.

[0014] An example of a PCCT system that can be used to perform contrast-enhanced scans in accordance with the present technology is presented in Figures 1 and 2. Figure 3 shows an exemplary mesh detector element of a PCCT system, where each mesh detector element counts X-ray photons directed toward the subject by an X-ray source. Each mesh detector element can include a metal layer disposed on a p-type semiconductor layer and arranged in longitudinal strips. The longitudinal strips of each mesh detector element can collect and transfer charge carriers from the detector array to a signal readout trace for image analysis. Each mesh detector element includes apertures disposed between the longitudinal strips to reduce the capacitance of the mesh detector element. The longitudinal strips and apertures are shown in detail in Figure 4. Figures 5 and 6 show cross-sectional views of mesh detector elements disposed on p-type, n-type, and oxide layers of a detector array. The n-type semiconductor layer collects photons of X-ray radiation and converts them into charge carriers. The charge carriers are then transferred to the longitudinal strips of each mesh detector element and transmitted as electrical signals to an image processing unit. 7 and 8 show a portion of an exemplary detector array, including an arrangement of mesh detector elements arranged in the plane of a semiconductor layer. Additionally, FIGS. 9 and 10 show an exemplary detector array including multiple detectors arranged in multiple rows, where incident X-ray radiation can pass through the edge of the detector array and travel vertically down the rows. Each beam of incident X-ray radiation is converted into charge carriers, and one or more of these charge carriers are collected and transferred by the multiple detectors.

[0015] 1-10 illustrate exemplary configurations of the relative positional relationships of various components. When elements are shown to be in direct contact with each other or directly coupled to each other, such elements can, at least in one example, be referred to as being in direct contact with each other or directly coupled to each other. Similarly, elements shown as being continuous or adjacent to each other can, at least in one example, be referred to as being continuous with each other or adjacent to each other, respectively. As one example, components that are in surface contact with each other can be referred to as being in surface contact with each other. As another example, in at least one example, elements that are spaced apart from each other, with only a space between them and no other components present, can be referred to as being spaced apart from each other. As yet another example, elements that are shown above / below / directly below each other, opposite each other, or left / right of each other can be referred to as being shown above / below / directly below each other, opposite each other, or left / right of each other. Furthermore, as shown in the figures, in at least one example, the top element or a point on the top element can be referred to as the "top" of the element, and the bottom element or a point on the bottom element can be referred to as the "bottom" of the element. As used herein, top / bottom, upper / lower, and above / lower are relative to the vertical axis of the figure and can be used to describe the relative positions of elements in the figure. Thus, an element shown above another element can, in one example, be positioned above and perpendicular to the other element. As yet another example, the shapes of elements shown in the figures can be referred to as having those shapes (e.g., circular, rectilinear, flat, curved, rounded, chamfered, angled, etc.). Furthermore, elements shown to intersect each other can, in at least one example, be referred to as intersecting elements or intersecting each other. Furthermore, elements shown within or outside of other elements can, by way of example, be referred to as being shown within or outside of other elements.

[0016] FIG. 1 illustrates an exemplary PCCT system 100 configured to perform CT imaging using photon-counting detectors. In particular, the PCCT system 100 is configured to image an object 112 (e.g., a patient), an inanimate object, one or more manufactured parts, and / or a foreign object present in the body (e.g., a dental implant, a stent, and / or a contrast agent). In some embodiments, the PCCT system 100 includes a gantry 102, which may further include an X-ray source 104 configured to emit an X-ray radiation beam 106 (see FIG. 2 ) for use in imaging the object 112 residing on a table 114. Specifically, the X-ray source 104 is configured to emit the X-ray radiation beam 106 toward a detector array 108 disposed on the opposite side of the gantry 102. While a single X-ray source 104 is illustrated in FIG. 1 , in some embodiments, multiple X-ray sources and multiple detectors may be employed to emit multiple X-ray radiation beams and acquire projection data at different energy levels corresponding to the patient. In some embodiments, the X-ray source 104 enables dual-energy gemstone spectral imaging (GSI) through rapid switching of peak kilovoltage (kVp). In the embodiments described herein, the X-ray detector employed is a photon-counting detector capable of distinguishing between X-ray photons of different energies.

[0017] In some examples, the PCCT system 100 further includes an image processing unit 110 configured to reconstruct an image of the target volume of the object 112 using an iterative or analytical image reconstruction method. For example, the image processing unit 110 may reconstruct an image of the target volume of the patient using an analytical image reconstruction technique (such as filtered back projection (FBP)). As another example, the image processing unit 110 may reconstruct an image of the target volume of the object 112 using an iterative image reconstruction technique (such as advanced statistical iterative reconstruction (ASIR), conjugate gradient (CG), maximum likelihood expectation maximization (MLEM), model-based iterative reconstruction (MBIR), etc.). As described further herein, in some embodiments, the image processing unit 110 may use an analytical image reconstruction technique (such as FBP) in addition to an iterative image reconstruction technique.

[0018] In some CT imaging system configurations, an x-ray source emits a cone-shaped beam of x-ray radiation that is collimated to span the XYZ plane of a Cartesian coordinate system and is commonly referred to as the "image plane." The x-ray radiation beam passes through the object being imaged (such as a patient or subject). After being attenuated by the object, the x-ray radiation beam impinges on an array of detector elements. The intensity of the attenuated x-ray radiation beam received at the detector array depends on the attenuation of the x-ray radiation beam by the object. Each detector element in the array produces a separate electrical signal that is a measurement of the x-ray beam attenuation at the detector location. The attenuation measurements from all detector elements are acquired separately to create a transmission profile.

[0019] In some CT systems, the x-ray source and detector array are rotated by a gantry in an imaging plane around the object to be imaged so that the angle at which the x-ray beam intersects the object is constantly changing. A group of x-ray radiation attenuation measurements (e.g., projection data) obtained from the detector array at one gantry angle is called a "view." A "scan" of the object involves a set of views made at different gantry angles, or view angles, during one revolution of the x-ray source and detector.

[0020] FIG. 2 illustrates an exemplary imaging system 200 similar to the PCCT system 100 of FIG. 1. In aspects of the present disclosure, the imaging system 200 is configured to image a subject 204 (e.g., subject 112 of FIG. 1). In one embodiment, the imaging system 200 includes the detector array 108 of FIG. 1. The detector array 108 further includes a plurality of detector elements 202. The plurality of detector elements 202 senses an x-ray radiation beam 106 (see FIG. 2) passing through the subject 204 (e.g., a patient) to acquire corresponding projection data. In some embodiments, the detector array 108 is fabricated in a multi-slice configuration including multiple rows of cells or detector elements 202. In such a configuration, one or more additional rows of detector elements 202 are arranged in a parallel configuration to acquire projection data.

[0021] In some examples, the imaging system 200 is configured to move through different angular positions around the object 204 to acquire desired projection data. Thus, the gantry 102 and the components mounted on the gantry may be configured to rotate about a center of rotation 206, for example, to acquire projection data at different energy levels. Alternatively, in embodiments in which the projection angle changes relative to the object 204 as a function of time, the mounted components may be configured to move along a general curve rather than along a circular arc.

[0022] As the X-ray source 104 and detector array 108 rotate, the detector array 108 collects data of the attenuated X-ray beam. The data collected by the detector array 108 is pre-processed and calibrated to adjust the data to represent the line integrals of the attenuation coefficients of the scanned object 204. The processed data is commonly referred to as a projection. In some embodiments, the individual detectors or detector elements 202 of the detector array 108 may include photon-counting detectors that record individual photon interactions in one or more energy bins.

[0023] The acquired set of projection data can be used for reference material decomposition (BMD). During BMD, the measured projections are converted into a set of material density projections. The material density projections can be reconstructed to form a pair or set of material density maps or images for each reference material (such as bone, soft tissue, and / or contrast agent). These density maps or density images can be correlated in order to form a 3D volumetric image of the reference material (e.g., bone, soft tissue, and / or contrast agent) in the imaging volume.

[0024] Once reconstructed, the reference material images produced by the imaging system 200 reveal internal features of the subject 204 that are represented by the densities of the two reference materials. The density images can be displayed to show the internal features. In a traditional approach to diagnosing a medical condition (such as a disease state), or more generally, diagnosing a medical event, a radiologist or physician would review a hard copy or displayed density image to identify features of interest. Such features might include lesions, the size and shape of particular anatomical structures or organs, and other features that would be identifiable in the image based on the skill and knowledge of the individual practitioner.

[0025] In one embodiment, imaging system 200 includes a control mechanism 208 that controls the movement of components, such as the rotation of gantry 102 and the operation of x-ray source 104. In some examples, control mechanism 208 further includes an x-ray controller 210 configured to provide power and timing signals to x-ray source 104. Furthermore, control mechanism 208 includes a gantry motor controller 212 configured to control the rotational speed and / or position of gantry 102 based on imaging requirements.

[0026] In some examples, the control mechanism 208 further includes a data acquisition system (DAS) 214 configured to sample analog data received from the detector elements 202 and convert the analog data to a digital signal for subsequent processing. The DAS 214 may be further configured to selectively aggregate analog data from a subset of the detector elements 202 into a so-called macro-detector, as described further herein. The data sampled and digitized by the DAS 214 is transmitted to a computer or computing device 216. Note that the computing device 216, in at least one embodiment, may be the same as or similar to the image processing unit 110. In some examples, the computing device 216 stores the data in a storage device 218 (e.g., a mass storage device). The storage device 218 may be, for example, any type of non-transitory memory, including a hard disk drive, a floppy disk drive, a compact disk read / write (CD-R / W) drive, a digital versatile disk (DVD) drive, a flash drive, and / or a solid-state storage drive.

[0027] Additionally, the computing device 216 provides commands and parameters to one or more of the DAS 214, the X-ray controller 210, and the gantry motor controller 212 to control system operations (such as data acquisition and / or data processing). In some examples, the computing device 216 controls system operations based on operator input. The computing device 216 receives operator input, including, for example, commands and / or scanning parameters, by an operator console 220 operably coupled to the computing device 216. The operator console 220 may include a keyboard (not shown) or a touch screen to enable an operator to specify commands and / or scanning parameters.

[0028] 2, more than one operator console 220 may be coupled to imaging system 200, for example, to input or output system parameters, request exams, present data, and / or view images. Additionally, in some examples, imaging system 200 may be coupled through one or more configurable wired and / or wireless networks (such as the Internet and / or virtual private networks, wireless telephone networks, wireless local area networks, wired local area networks, wireless wide area networks, wired wide area networks, etc.) to multiple displays, printers, workstations, and / or similar devices located locally or remotely within a facility or hospital or at entirely different locations.

[0029] In some examples, the imaging system 200 includes or is coupled to a Picture Archiving and Communication System (PACS) 224. In an exemplary implementation, the PACS 224 is further coupled to remote systems (radiology information systems, hospital information systems) and / or internal or external networks (not shown) to allow an operator at another location to provide commands and parameters and / or access image data.

[0030] The computing device 216 uses operator-supplied and / or system-defined commands and parameters to operate the table motor controller 226. The table motor controller 226 can control the table 114, which can be a motorized table. Specifically, the table motor controller 226 can move the table 114 so that the subject 204 is properly positioned in the gantry 102 to acquire projection data corresponding to a target volume of the subject 204.

[0031] As previously mentioned, DAS 214 samples and digitizes the projection data acquired by detector elements 202. Image reconstructor 230 then performs high-speed reconstruction using the sampled and digitized x-ray data. While FIG. 2 illustrates image reconstructor 230 as a separate entity, in some examples, image reconstructor 230 may form part of computing device 216. Alternatively, image reconstructor 230 may not be present in imaging system 200; instead, computing device 216 may perform one or more functions of image reconstructor 230. Furthermore, image reconstructor 230 may be located locally or remotely and may be operably connected to imaging system 200 using a wired or wireless network. In particular, in one exemplary embodiment, computing resources in a “cloud” network cluster may be used for image reconstructor 230.

[0032] In some examples, image reconstructor 230 stores the reconstructed image in storage device 218. Alternatively, image reconstructor 230 may transmit the reconstructed image to computing device 216 for generating patient information useful for diagnosis and evaluation. In some examples, computing device 216 may transmit the reconstructed image and / or patient information to a display or presentation device 232 communicatively coupled to computing device 216 and / or image reconstructor 230. In some examples, the reconstructed image may be transmitted from computing device 216 or image reconstructor 230 to storage device 218 for short-term or long-term storage.

[0033] 3-10 illustrate coordinate systems for clarifying the direction of the views. In one example, the z-axis may be vertical (e.g., parallel to the axis of rotation of the CT gantry), the y-axis may be longitudinal (e.g., from the detector toward the source), and / or the x-axis may be horizontal (e.g., circumferential). However, these axes may have other directions in other examples.

[0034] Referring now to FIG. 9 , a detector array 900 is shown. The detector array 900 may be a non-limiting example of one sensor of the detector array 108 of FIG. 1 . In some examples, the detector array 108 of FIG. 1 may include more than 100 sensors (e.g., detector array 900) arranged in chiclets and / or modules of the detector array 108. Multiple detectors 901 may be arranged in a parallel configuration to form the detector array 900, which may be used to acquire projection data as described above. Additionally, FIG. 10 shows an enlarged view of a region 1000 of the detector array 900 that includes a portion of the multiple detectors 901. FIGS. 9 and 10 are described together herein.

[0035] Detector array 900 can include multiple detectors 901 and a printed circuit board (PCB) 920. In the example shown in FIG. 9 , multiple detectors 901 and PCB 920 are arranged vertically relative to the y-axis. Additionally, arrow 922 points parallel to the y-axis and indicates a typical direction of incident X-ray radiation in the exemplary embodiment. PCB 920 can be positioned below multiple detectors 901 such that the PCB is not between multiple detectors 901 and the incident X-ray radiation. Furthermore, positioning PCB 920 below multiple detectors 901 (e.g., downward in the y-axis) can allow multiple detector arrays (such as detector array 900) to be space-efficiently positioned in a detector chiclet and / or module (e.g., detector array 108 of FIG. 2 ).

[0036] The detector array 900 may include a layer of semiconductor material (e.g., semiconductor layer 1011). The plurality of detectors 901 may be disposed on a plane 1012 of the semiconductor layer 1011. Furthermore, the semiconductor layer 1011 may have a width W6 in the range of 100 μm to 1000 μm (e.g., 500 μm or 650 μm). As shown in FIG. 10 , the detector array 900 may include a guard ring 1002. The guard ring 1002 may be configured to include one or more narrow structures extending along each edge of the plane 1012 and surrounding the plurality of detectors 901. In an exemplary embodiment, each such narrow structure includes a p-type semiconductor layer and a metal layer on the plane 1012 of the semiconductor layer. In another embodiment, the guard ring includes a plurality of concentric narrow structures that collectively act as a guard ring structure. The guard ring 1002 protects the detector array 900 from electrical breakdown (avalanche breakdown) of the semiconductor layers by limiting the maximum electric field.

[0037] The multiple detectors 901 can be electronically coupled to one or more application specific integrated circuits (ASICs) (such as a first ASIC 906 and a second ASIC 908 mounted on a PCB 920). As described in more detail below, each of the first ASIC 906 and the second ASIC 908 can calculate the number of photon counts detected by the multiple detectors 901. The multiple detectors 901 can be coupled to the first ASIC 906 and the second ASIC 908 through wire bonds 926 running between the multiple detectors and the PCB 920. Additionally, the multiple detectors 901 may alternatively be directly coupled to the ASICs 906 and 908 through wire bonds. Additionally, the PCB 920 can be electrically connected to readout electronics, which can also be used to calculate the number of photons detected by the multiple detectors 901. In some examples, the readout electronics can be circuitry external to the PCB 920 (e.g., for use during assembly and testing). Additionally, the readout electronics may form part of the DAS (eg, DAS 214 of FIG. 2) of the PCCT system.

[0038] The plurality of detectors 901 can be configured to detect photons of X-ray radiation that pass through an edge 902 of the semiconductor layer 1011 of the detector array 900. The edge 902 can have a width W6 (e.g., 500 μm or 600 μm) along the z-axis. Furthermore, the edge 902 can be oriented orthogonal to the plane 1012. In this manner, the plurality of detectors 901 can be positioned on a surface of the detector array 900 that is perpendicular to the incident X-ray radiation.

[0039] The multiple detectors 901 can be arranged in multiple columns, with each column extending along the y-axis. For example, the multiple detectors 901 can include a first column 1008 and a second column 1010. Each column can include one or more detectors (such as a first detector 1014 and a second detector 1016 in the first column 1008). A column of detectors (e.g., the first column 1008) and a portion of the semiconductor layer 1011 behind the column of detectors (e.g., behind the z-axis) can be defined as a pixel, and thus the detector array 900 can include multiple pixels. For example, pixel 1018 can include the first column 1008 (e.g., the first detector 1014 and the second detector 1016) and a portion of the semiconductor layer 1011 behind the first column behind the z-axis.

[0040] Each pixel may include a pixel area on the edge 902 of the detector array 900. When incident X-ray radiation enters the pixel area, photons of the X-ray radiation beam may interact with the semiconductor layer 1011 and release energy. This energy is converted to charge carriers within the corresponding pixel. For example, pixel 1018 may include pixel area 1006 on the edge 902 of the detector array 900. When incident X-ray radiation enters the pixel area 1006, the photons of the X-ray radiation are converted to charge carriers within a portion of the semiconductor layer 1011 located below the pixel area (e.g., below with respect to the y-axis), and the charge carriers are detected by the detectors in the first column 1008. In this manner, each pixel (e.g., pixel 1018) may receive incident X-ray radiation at the pixel area on the edge 902, convert the X-ray radiation to charge within the semiconductor layer 1011, and collect the charge with a detector within the pixel. The charge collected by the multiple detectors 901 can then be transmitted over signal readout traces to one or more ASICs in the detector array.

[0041] 9, each column of detectors (e.g., first column 1008 in FIG. 10) may extend from the top of detector array 900 along the Y-axis to PCB 920. The detectors in each column may be further arranged in one or more rows of detector array 900 (e.g., first row 910 and second row 912).

[0042] Each row of the plurality of detectors 901 includes one detector in each column. For example, a column 924 of the plurality of detectors 901 may include one detector in the first row 910 and one detector in the second row 912. Furthermore, the column 924 may include one detector in each of the third row 914, the fourth row 916, and the fifth row 918. In some examples, the detectors in one row may have a different length than the detectors in different rows. For example, the detectors in the first row 910 may have a shorter length in the y-axis than the detectors in the second row 912. In this way, the entire first row 910 may have a shorter length in the y-axis than the entire second row 912. In other examples, the detectors in each row may have the same length. For example, the detectors in the first row may have the same length in the y-axis as the detectors in the second row. In this way, the entire first row may have the same length in the y-axis as the detectors in the second row.

[0043] Each detector of the plurality of detectors 901 (e.g., the first detector 1014 in FIG. 10 ) may be electrically coupled to a first ASIC 906 and / or a second ASIC 908 mounted on the PCB 920. In some examples, each detector of the plurality of detectors 901 may be electrically coupled to a sensor bond pad through a signal readout trace. Further, the sensor bond pad may be electrically coupled to the first ASIC 906 and / or the second ASIC 908 through a wire bond that extends to the PCB 920. Each ASIC may be configured to receive electrical signals from one or more columns and / or rows of the detector array 900.

[0044] Furthermore, each detector of the plurality of detectors 901 can collect charge carriers generated by the semiconductor layer 1011 of FIG. 10 . The semiconductor layer 1011 can generate charge carriers after receiving multiple incident photons by one or more beams of X-ray radiation. When X-ray radiation strikes the detector array 900 at the end 902 (e.g., in the pixel region 1006), the photons of the X-ray radiation may pass through the semiconductor layer 1011 of the pixel. Each pixel includes a portion of the semiconductor layer and a column of the plurality of detectors 901. For example, a photon of X-ray radiation may strike the detector array 900 in the pixel region 1006 of FIG. 10 and then pass through the semiconductor layer 1011 corresponding to the first column 1008. When the X-ray radiation passes through the semiconductor layer 1011, the multiple photons of the X-ray radiation can be converted into charge carriers that are collected by the detectors of the corresponding column (e.g., the first column 1008).

[0045] For example, X-ray radiation may be incident on the semiconductor layer 1011 of a pixel, and a first number of photons may be converted into electrical charges in a portion of the semiconductor layer behind the first row 910 relative to the z-axis. A detector disposed in the first row 910 of pixels may collect the electrical charges generated from the first number of photons of X-ray radiation. The first number of photons may be less than the total number of photons of the X-ray radiation, and a second number of photons of the total number of photons may pass through the portion of the semiconductor layer 1011 behind the first row 910 without being detected. The (undetected) second number of photons of X-ray radiation may then be incident on the semiconductor layer 1011 behind the second row 912 of the same pixel, and a third number of photons may be converted into electrical charges. A detector in the second row 912 of pixels may collect the electrical charges generated from the third number of photons of X-ray radiation. The third number of photons is less than the second number of photons, and the fourth number of photons pass undetected through the portion of the semiconductor layer 1011 behind the second row 912, and so on.

[0046] Each electrical signal collected by the multiple detectors 901 can be transmitted to the first ASIC 906 or the second ASIC 908 via a signal readout trace. Furthermore, each electrical signal can be an analog electrical signal proportional to the amount of energy of the detected photon. The first ASIC 906 and the second ASIC 908 can convert each analog electrical signal to a digital signal by counting the occurrence of photons. Furthermore, each ASIC can identify the energy imparted by the photon by comparing the amount of the electrical signal with one or more preset thresholds. Specifically, the first ASIC 906 and the second ASIC 908 can each include multiple comparators, each of which outputs a trigger signal that increments a corresponding digital counter by one when the analog signal exceeds a signal level threshold associated with the comparator. Each comparator of the multiple comparators can have a different signal level threshold. For example, the first ASIC 906 may include a first comparator having a first signal level threshold and a second comparator having a second signal level threshold, which may be higher than the first signal level threshold. Furthermore, the first ASIC 906 may include a third comparator having a third signal level threshold, which may be higher than the second signal level threshold, with such threshold settings continuing up to the maximum energy level of the photon spectrum. The difference between these sets of thresholds defines an energy range or bin. Thus, the number of photons whose energy falls within each bin can be recorded by the ASIC. In this manner, the number of photon counts can be transmitted by the first ASIC 906 or the second ASIC 908 to the PCB 920 and used for image reconstruction. Alternatively, each ASIC may first perform additional operations on the numeric count information (such as summing the individual photon counts from the bins in a given column to generate a total number of photon counts).

[0047] Referring now to FIG. 3 , a detector array 301 is shown. The detector array 301 includes a first semiconductor layer with a plurality of mesh detector elements 300 disposed on top of the first semiconductor layer, thereby forming a plurality of mesh diodes. Each mesh diode includes a first semiconductor layer, a second semiconductor layer having an opposite doping polarity to the first semiconductor layer, an oxide layer, and a metal layer 318, as described herein. In some examples, the first semiconductor layer can be an n-type semiconductor and the second semiconductor layer can be a p-type semiconductor, as described herein. In other examples, the first semiconductor layer can be a p-type semiconductor and the second semiconductor layer can be an n-type semiconductor.

[0048] The plurality of mesh detector elements 300 may be non-limiting examples of detectors such as detector element 202 of FIG. 2 or the plurality of detectors 901 of FIG. 9. Each mesh detector element of the plurality of mesh detector elements 300 may collect charge carriers (e.g., electrical signals) generated from photons of X-ray radiation through a semiconductor. Furthermore, in the illustrated embodiment, the plurality of mesh detector elements 300 may include a first mesh detector element 302 and a second mesh detector element 303. The second mesh detector element 303 is similar to the first mesh detector element 302, and therefore, a description of the second mesh detector element 303 may be omitted for brevity, and the description of the first mesh detector element 302 provided herein similarly applies to the second mesh detector element 303 and additional mesh detector elements of the detector array 301.

[0049] The first mesh detector element 302 may include a metal layer 318. The metal layer 318 may include a first end 312 and a second end 314 and may extend from the first end 312 to the second end 314 along an axis parallel to the y-axis. The first end 312 may be located closer to an edge (such as edge 902 in FIG. 9 ) of the detector array configured to receive photons of x-ray radiation. As such, the first end 312 may be oriented toward an x-ray radiation source of a PCCT system (such as PCCT system 100 in FIG. 1 ). The second end 314 may be located away from the x-ray radiation source and may include a signal readout trace 316. The signal readout trace 316 may be configured to transmit electrical signals collected by the first mesh detector element 302 to an ASIC input of one or more components of an image processing system (such as image reconstructor 230 in FIG. 2 ).

[0050] In some examples, as described herein, the first mesh detector element 302 and the second mesh detector element 303 can each be disposed in a plane of an n-type semiconductor layer (e.g., silicon) selectively doped with p-type implants (referred to as an implant layer) in a spatially varying pattern. The plane can be oriented orthogonal to an edge of the detector that receives x-ray radiation. The entire implant layer (e.g., p-type silicon) can be disposed below a portion of the metal layer 318 relative to the z-axis. Additionally, as described with reference to FIGS. 5 and 6 , an oxide layer can be disposed between a portion of the metal layer 318 and portions of the n-type semiconductor layer and the implant layer. In other examples, the first mesh detector element 302 and the second mesh detector element 303 can each be disposed in a plane of a p-type semiconductor layer selectively doped with n-type implants.

[0051] The first mesh detector element 302 can include a plurality of openings 307, which include a first opening 306, thereby forming a plurality of longitudinal strips 305 (such as first longitudinal strip 304) in a metal layer 318 along the semiconductor (e.g., silicon) layer. Each opening of the plurality of openings 307 can include a gap in the metal layer 318 of the first mesh detector element 302 such that the metal layer does not extend continuously across the width (e.g., width relative to the x-axis) of the first mesh detector element. Furthermore, the implant layer can include a gap disposed beneath each opening such that the implant layer does not extend continuously across the width of the first mesh detector element within the n-type semiconductor layer. For example, the implant layer and the n-type semiconductor layer can each be disposed beneath a portion of the metal layer 318, with the n-type semiconductor layer, but not the implant layer, disposed beneath the opening 307. The longitudinal strips 305 may be configured to collect charge carriers generated from photons collected in a semiconductor layer below the first mesh detector element 302, as described with reference to FIG. 5 . The collected charge carriers may provide a photocurrent that is transferred to a signal readout trace 316 and measured by the ASIC. Each of the longitudinal strips 305 may include a metal layer 318 and may be positioned to cover a portion of the implant layer. Furthermore, each longitudinal strip of the plurality of longitudinal strips 305 may be positioned in an opening in the oxide layer, as described with reference to FIGS. 4-6 . In the illustrated embodiment, the first mesh detector element 302 includes five longitudinal strips 305, and each longitudinal strip may extend from a first end 312 to a second end 314 of the first mesh detector element. In some embodiments, the first mesh detector element 302 may include another suitable number of longitudinal strips.

[0052] In the illustrated example, the first mesh detector element 302 is indicated by dashed line 310, which represents the length of the first mesh detector element, which is not shown in FIG. 3 . Dashed line 310 allows both the first end 312 and the second end 314 to be shown in FIG. 3 . Without dashed line 310, both the first end 312 and the second end 314 would not be visible in FIG. 3 due to the length L1 of the first mesh detector element 302 relative to the length of an individual portion of the first mesh detector element (such as the length L2 of one of the plurality of apertures 307). In some examples, the first mesh detector element 302 may have a length L1 in the range of 3 to 20 mm. Furthermore, in some examples, each opening of the plurality of apertures 307 may have a length L2 in the range of 0.25 to 5 mm. In other examples, the first mesh detector element 302 and the aperture 307 may have other suitable lengths, in which the length of the aperture is shorter than the length of the first mesh detector element.

[0053] The opening 307 in the first mesh detector element 302 is a region that does not include the metal layer 318, and no portion of the implant layer is disposed below the opening. However, an oxide layer and an n-type semiconductor layer are disposed below the opening 307, as described with reference to FIGS. 4-5 . The opening 307 can act to reduce the capacitance of the first mesh detector element 302 by reducing the area of ​​the first mesh detector element that collects charge carriers and / or through which photocurrent can flow. Reducing the capacitance of the first mesh detector element 302 can reduce the electronic noise of the first mesh detector element, and therefore, can increase the detection quality and / or detection sensitivity.

[0054] The openings 307 do not extend continuously from the first end 312 to the second end 314, but instead are separated by horizontal bridges 308. Similar to the longitudinal strips 305, the horizontal bridges 308 can be configured to collect and transport charge carriers generated from incident photons. Each horizontal bridge of the plurality of horizontal bridges 308 can include a metal layer 318 and can be disposed over an implant layer. Additionally, an opening in an oxide layer can be disposed below each horizontal bridge of the plurality of horizontal bridges 308, as described with reference to FIGS. 4-6. The horizontal bridges 308 can be oriented perpendicular to the longitudinal strips 305 and thus can have a longitudinal axis parallel to the x-axis. Furthermore, the horizontal bridges 308 can extend beyond each longitudinal strip of the plurality of longitudinal strips 305. In this manner, each opening of the plurality of openings 307 is surrounded (e.g., in the xy plane) by two longitudinal strips of the plurality of longitudinal strips 305 and one or more horizontal bridges of the plurality of horizontal bridges 308.

[0055] In the illustrated embodiment, the first mesh detector element 302 includes four openings 307 disposed between the first end 312 and the first horizontal bridge of the plurality of horizontal bridges 308. Similarly, the first mesh detector element 302 includes four openings 307 disposed between the last horizontal bridge of the plurality of horizontal bridges 308 and the second end 314 of the first mesh detector element, and between each set of consecutive horizontal bridges of the plurality of horizontal bridges 308. In some examples, the first mesh detector element 302 may include a different number of openings 307 disposed between the first end 312 and the horizontal bridge, between the second end 314 and the horizontal bridge, and / or between consecutive horizontal bridges of the plurality of horizontal bridges 308. Each opening of the plurality of openings 307 may have a width W3 (e.g., 35 μm) in the range of 20 μm to 50 μm, as shown in FIG. 4 . In some examples, the openings 307 may have another suitable width.

[0056] The longitudinal strips 305 may be oriented such that their longitudinal axes are parallel to the y-axis (e.g., parallel to the direction of incident X-ray photons). Furthermore, each of the plurality of longitudinal strips 305 may have a width W1 (e.g., 25 μm) in the range of 10 μm to 50 μm, as shown in FIG. 4 . In some examples, the longitudinal strips 305 may have another appropriate width. The number and width W1 of the longitudinal strips 305 may be determined based on the width W2 of the first mesh detector element 302 along the x-axis, which is in the range of 150 μm to 1000 μm (e.g., 500 μm). It may be desirable for the total area of ​​the apertures 307 (e.g., the sum of the areas of each aperture) to be equal to a certain percentage (e.g., ratio) of the area of ​​the first mesh detector element 302. The ratio between the total area of ​​the aperture 307 and the area of ​​the first mesh detector element 302 is at least 10% and not more than 75% (in some cases a value in the range of 55% to 65%).

[0057] A ratio between the total area of ​​the aperture 307 and the area of ​​the first mesh detector element 302 of 55% to 65% provides an ideal balance between reducing the capacitance (e.g., electronic noise) of the first mesh detector element and maintaining sufficient detection efficiency (e.g., charge collection area). For example, if the ratio of the total aperture area to the area of ​​the first mesh detector element 302 is small (e.g., 10%), the detection efficiency of the first mesh detector can be improved by increasing the area for charge collection, but the amount of reduction in the capacitance (e.g., electronic noise reduction) of the first mesh detector may be small. Alternatively, if the ratio of the total aperture area to the area of ​​the first mesh detector element is large (e.g., 75%), the capacitance (e.g., electronic noise) of the first mesh detector element can be significantly reduced, but the area for charge collection may be small, resulting in insufficient detection efficiency. Furthermore, the ratio between the overall aperture area and the area of ​​the first mesh detector is specifically selected to maintain the detection efficiency of the edge-on detector array, where X-ray photons do not directly impinge on the first mesh detector elements.

[0058] 4 shows a portion of a first mesh detector element 302, including a first end 312, a longitudinal strip 305, and an opening 307. The first mesh detector element 302 may have a width W2, and each longitudinal strip of the plurality of longitudinal strips 305 may have a width W1. The widths W2 and W1 correspond to the width of the metal layer 318 across the entire first mesh detector element and across the longitudinal strips, respectively. Furthermore, each opening of the plurality of openings 307 may have a width W3, as described with reference to FIG. 3.

[0059] The first mesh detector element 302 may be disposed in a semiconductor layer as described with reference to FIG. 5 and may be configured to receive photons of X-ray radiation. Furthermore, the metal layer 318 of the first mesh detector element 302 may be disposed on an implant layer 404. The implant layer 404 may be a p-type extrinsic semiconductor (e.g., an intrinsic semiconductor doped with impurities). As such, the implant layer 404 may be doped with an electron acceptor element and may have a higher hole concentration (e.g., electrons are the minority carriers) than the electron concentration. In some examples, the implant layer 404 may include a boron- or gallium-doped region of a semiconductor layer. The implant layer 404 may be in contact with an n-type semiconductor (such as the semiconductor layer 502 of FIG. 5). Furthermore, an oxide layer 506 (shown in FIG. 6) may be disposed above the implant layer 404 and the semiconductor layer and below the metal layer 318 relative to the z-axis. The oxide layer may include oxide openings 406 extending along the metal layer 318 and the implant layer 404. The metal layer 318 can be configured to collect charges generated in the n-type semiconductor layer that have passed through the implant layer 404 of the first mesh detector element 302. The metal layer 318 can include aluminum, an aluminum-silicon alloy, an aluminum-copper alloy, copper, tungsten, titanium, or other metals compatible with device manufacturing production lines. The metal can also be composed of multiple layers, such as an initial adhesion layer (e.g., titanium), a diffusion blocking layer (e.g., nickel), and a thick layer of a main conductor material (e.g., aluminum).

[0060] As shown in FIG. 4 , the first end region 412 extends from the first end 312 of the metal layer 318 to the beginning of the opening 307. The first end region 412 may be a region of the first mesh detector element 302 that does not include the opening and therefore includes the metal layer 318, the implant layer 404, a portion of the oxide layer, and the oxide opening 406. The first end region 412 may have a length L3 (e.g., 40 μm) in the range of 20 μm to 100 μm (L3 defined by the length of the metal layer 318). Additionally, the first end region 412 may include rounded outer corners 408. The rounded outer corners 408 are beneficial for preventing voltage drop within the first mesh detector element 302. The rounded outer corners 408 can increase the dielectric strength of the first mesh detector element 302, and therefore the voltage required to cause electrical breakdown of the first mesh detector element 302, compared to when the first mesh detector element 302 has non-rounded outer corners. The rounded outer corners 408 can have a radius of curvature ranging from 20 μm to 80 μm, such as 45 μm.

[0061] The longitudinal strips 305 may have a longitudinal axis parallel to the y-axis. The longitudinal strips 305 may include a metal layer 318 and may be disposed over the implant layer 404 and the oxide openings 406. The metal layer 318 of each longitudinal strip 305 may have the same width W1 as the longitudinal strip (e.g., 35 μm). The implant layer 404 disposed below each longitudinal strip of the plurality of longitudinal strips 305 may have a width W4 that is narrower than the width W3 by a value in the range of 5 μm to 25 μm (e.g., 16 μm). The oxide openings 406 disposed below each longitudinal strip 305 may have a width W5 that is narrower than the width W4 by a value in the range of 2 μm to 20 μm (e.g., 6 μm). In some embodiments, the metal layer 318 of the longitudinal strips 305, as well as the implant layer 404 and oxide openings 406 disposed below each longitudinal strip, may have other suitable widths.

[0062] The openings 307 can have a longitudinal axis parallel to the y-axis and thus parallel to the longitudinal strips 305. Furthermore, the openings 307 may not include the metal layer 318, and the implant layer 404 and oxide openings 406 may not be disposed below the metal layer. Instead, the openings 307 may be disposed above the oxide layer and n-type semiconductor layer, as described with reference to FIG. 5.

[0063] Each opening of the plurality of openings 307 can include a curved inner corner 410, with each curved inner corner extending along an inner edge of the metal layer 318. For example, the metal layer 318 can have an inner edge 413 that forms a first curved inner corner 411. The inner edge 413 extends linearly along the y-axis to a first transition region 414, where the inner edge curves upward (e.g., toward the first end 312) to a point 416, then curves downward to a second transition region 418, where the inner edge again extends linearly along the y-axis. In some embodiments, the curved inner corner 410 can have a radius of curvature ranging from 5 μm to 100 μm (e.g., 25 μm). In other embodiments, the curved inner corner 410 can have a different suitable radius of curvature. Furthermore, the implant layer 404 and the oxide opening 406 are curved at the curved inner corner 410, but have different suitable radii of curvature. The curved inner corners 410 may help prevent a voltage drop within the first mesh detector element 302. The curved inner corners 410 may increase the dielectric strength of the first mesh detector element 302 compared to when the first mesh detector element 302 has non-curved inner corners, and therefore may increase the voltage required to cause an electrical breakdown of the first mesh detector element.

[0064] FIG. 5 shows a cross-sectional view of a first mesh detector element 302 including a semiconductor layer 502, taken along section line A1 shown in FIG. 4 . As shown in FIG. 5 , the first mesh detector element 302 includes a metal layer 318 disposed on the semiconductor layer 502, an implant layer 404 disposed on the semiconductor layer 502, and an oxide layer 506 disposed above the semiconductor layer 502 and below the metal layer 318. A common backside electrode 504 may be deposited on a bottom surface of the semiconductor layer 502 relative to the z-axis. In some examples, the common backside electrode 504 may have a thickness of approximately 1 μm along the z-axis. It should be understood that the semiconductor layer 502, the oxide layer 506, and the common backside electrode 504 may each extend beyond the first mesh detector element 302 to form the semiconductor layer, oxide layer, and common electrode of each mesh detector element in the detector array. Furthermore, an isolation region 510 surrounds the first mesh detector element 302, and the isolation region may be located between the first mesh detector element and other mesh detector elements. Similarly, an isolation region 510 may extend between each mesh detector element and its neighboring mesh detector element, such that the mesh detector elements are separated by the isolation region. The isolation region 510 may include the semiconductor layer 502, the oxide layer 506, and the common backside electrode 504.

[0065] The semiconductor layer 502 can have a height H1 in the range of 200 μm to 1000 μm (e.g., 500 μm), where the height H1 ranges from the bottom surface of the semiconductor layer to the top surface of the semiconductor layer along the z-axis. In some examples, the first mesh detector element 302 may have a different height.

[0066] The semiconductor layer 502 may be silicon in some examples. Furthermore, the semiconductor layer 502 may be an n-type extrinsic semiconductor (e.g., an intrinsic semiconductor doped with impurities). Thus, the semiconductor layer 502 may be doped with an electron acceptor element and have a higher electron concentration than a hole concentration (e.g., electrons are the majority carriers). In some examples, the semiconductor layer 502 may include silicon doped with phosphorus, arsenic, antimony, or bismuth. The semiconductor layer 502 may be bonded to a p-type semiconductor (such as the implant layer 404). As shown, the semiconductor layer 502 may be disposed below (e.g., below with respect to the z-axis) and next to (e.g., next to) the implant layer 404 (e.g., with respect to the x-axis). Furthermore, the implant layer 404 may be disposed below a portion of the metal layer 318 of each longitudinal strip of the plurality of longitudinal strips 305 of the first mesh detector element 302.

[0067] The semiconductor layer 502 can be configured to receive photons of X-ray radiation at a first end (e.g., edge 902 in FIG. 9 ). The X-ray photons are absorbed in the semiconductor layer 502 and converted to charge carriers, which can transmit an electrical signal. The charge carriers can travel at least partially along the z-axis through the semiconductor layer 502, through the implant layer 404, and to the metal layer 318 of the longitudinal strip 305, where they can travel to a second end of the first mesh detector element 302 (e.g., second end 314 in FIG. 3 ). Furthermore, the charge carriers can travel as an electrical signal from the first mesh detector element 302 through a signal readout trace (such as signal readout trace 316 in FIG. 3 ) to the ASIC.

[0068] The common back electrode 504 can be disposed below the semiconductor layer 502 relative to the z-axis. An electrical bias potential (e.g., a voltage) can be applied to the common back electrode 504 relative to the potential of the mesh detector to form an electric field applied to the semiconductor layer. In this manner, the common back electrode 504 can influence charge carriers of one charge polarity generated in the semiconductor layer 502 to migrate toward the metal layer 318 of the first mesh detector element 302 (e.g., away from the common back electrode 504 relative to the z-axis), while charge carriers of the opposite polarity migrate toward the common back electrode 504.

[0069] The metal layer 318 may be disposed above the semiconductor layer 502 with respect to the z-axis. Similarly, a portion of the metal layer 318 may be disposed above the implant layer 404. The oxide opening 406 may be located intermediate the metal layer 318 and the implant layer 404 with respect to the z-axis. The portion of the metal layer 318 may be in surface contact with a portion of the implant layer 404 through the oxide opening 406. Therefore, charge carriers generated in the semiconductor layer 502 may travel through the implant layer 404 and the oxide opening 406 to the metal layer 318. The oxide layer 506 may separate the metal layer 318 and the implant layer 404 at a location other than the oxide opening 406. Furthermore, the oxide layer 506 may be disposed intermediate the portion of the metal layer 318 and the portion of the semiconductor layer 502, preventing the portion of the metal layer from being in surface-to-surface contact with the semiconductor layer. The oxide layer 506 will be further described with reference to FIG. 6 .

[0070] The opening 307 of the first mesh detector element 302 may be located between the longitudinal strips 305 relative to the x-axis. The opening 307 may be free of the metal layer 318, and the oxide layer 506 may be the top layer of the diode opening relative to the z-axis. In this manner, the opening 307 acts to reduce the capacitance of the first mesh detector element 302 by reducing the area of ​​the metal layer 318.

[0071] Figure 6 shows an enlarged view of region 508 of the cross-sectional view shown in Figure 5, including a portion of one longitudinal strip of the plurality of longitudinal strips 305 and two openings of the plurality of openings 307 of the first mesh detector element 302. Each of the semiconductor layer 502, metal layer 318, implant layer 404, oxide layer 506, and oxide opening 406 are shown.

[0072] The oxide layer 506 can be thin compared to the semiconductor layer 502 and can have a height in the range of 0.2 μm to 10 μm. The oxide layer 506 can be disposed above the semiconductor layer 502 with respect to the z-axis, and a portion of the oxide layer can be in surface contact with the semiconductor layer. The oxide layer 506 and the semiconductor layer 502 can be in surface contact except at the location of the implant layer 404, where a portion of the oxide layer 506 can be in surface contact with the implant layer, and the implant layer is embedded in the semiconductor layer 502. Furthermore, the oxide layer 506 can have a termination edge positioned such that the oxide opening 406 is located at the center of the implant layer 404 (e.g., centered with respect to the x-axis). The oxide opening 406 allows a portion of the metal layer 318 to be in surface contact with the implant layer 404.

[0073] The metal layer 318 terminates at a first edge 602 and a second edge 604, and the opening 307 can originate at the first and second edges and extend outward from the metal layer along the x-axis. The first and second edges 602 and 604 can be located above the semiconductor layer 502 and the oxide layer 506, with the oxide layer being disposed above the semiconductor layer along the z-axis. In this manner, the oxide layer 506 can be exposed to the ambient environment through the opening 307. Furthermore, a portion of the oxide layer 506 and a portion of the semiconductor layer 502 are in surface contact.

[0074] The first mesh detector element 302 may be a non-limiting example of the first detector 1014 of Figure 10. As such, the detector array 900 of Figure 9 may include a plurality of mesh detector elements similar to the first mesh detector element 302. Furthermore, when arranged in a detector array (e.g., the detector array 900), the plurality of mesh detector elements (e.g., the first mesh detector element 302) may be formed on a planar surface of a semiconductor layer and arranged in rows and / or columns. The plurality of mesh detector elements may be spaced apart to reduce the size of the dead / inactive areas of the detector array while reducing manufacturing complexity.

[0075] FIG. 7 illustrates a portion of an exemplary detector array 700. The portion of the illustrated detector array 700 includes a corner 701 of the detector array. In some examples, the corner 701 can be rounded. In other examples, the corner 701 is not rounded and instead may include two straight edges that meet at an angle (e.g., 90 degrees). The detector array 700 may include multiple detector elements (e.g., a first mesh detector element 706, a second mesh detector element 708, and a third mesh detector element 710). Additionally, the detector array 700 may include a semiconductor region 714, an outer edge 702, and a guard ring 704. The detector array 700 may include a common backside electrode (not shown), such as the common backside electrode 504 of FIG. 5.

[0076] The semiconductor region 714 may include a portion of the detector array 700 where no mesh detector elements (e.g., the first mesh detector element 706) are located. The semiconductor region 714 may include a semiconductor layer and an oxide layer, where the oxide layer is located above (e.g., above with respect to the z-axis) and in surface contact with the semiconductor layer. In this manner, the semiconductor region 714 may be similar to the isolation region 510 of FIG. 5.

[0077] The outer edge 702 can function as the outer edge of the detector array 700. As such, the outer edge 702 can extend entirely around the detector array 700, with no detector array components extending beyond the outer edge. The outer edge 702 can include one or more straight edges and one or more corners (such as the straight edge 703 and the corner 701). In some examples, the straight edge 703 may not be aligned with the y-axis and may not be parallel to the edges of the first mesh detector element 706 and the second mesh detector element 708. For example, the bottom of the straight edge 703 can be further away from the top along the x-axis than the top of the straight edge with respect to the y-axis (e.g., the bottom of the straight edge 703 can be angled inward). In this manner, the detector array 700 can accommodate PCCT detector chiclets and / or modules that include non-orthogonal sides. In other examples, the straight edge 703 may be aligned with the x-axis and / or perpendicular to the straight edge next to the outer edge 702. A guard ring 704 may be disposed between the outer edge 702 and a mesh detector element (such as the third mesh detector element 710) such that the mesh detector element is separated from the outer edge. Additionally, the guard ring 704 may define the outer boundary of a semiconductor region 714 (e.g., an active region of the semiconductor) where x-ray generated charge carriers may be measured. Charge carriers generated between the guard ring 704 and the outer edge 702 are collected by the guard ring 704. Such collected charge may be measured by system electronics but does not form part of the imaging data.

[0078] The first mesh detector element 706 may include a longitudinal strip, an opening, and a horizontal bridge, which may be similar to the longitudinal strip 305, the opening 307, and the horizontal bridge 308, respectively, of FIG. 3 . The second mesh detector element 708 may include a longitudinal strip and an opening, which may be similar to the longitudinal strip 305 and the opening 307, respectively. The second mesh detector element 708 may not include a horizontal bridge. In some embodiments, the second mesh detector element 708 may be short such that a horizontal bridge is not needed to collect and / or transfer charge carriers, and thus the horizontal bridge may be omitted from the second mesh detector element. For example, the first mesh detector element 706 may be longer than the second mesh detector element 708, and thus the first mesh detector element may include a horizontal bridge to increase the size of the metal layer of the first mesh detector element, while the second mesh detector element may not include a horizontal bridge. Furthermore, the longitudinal strips and openings of the second mesh detector elements 708 may be longer than the longitudinal strips and openings of the first mesh detector elements 706 .

[0079] The third mesh detector element 710 may include a longitudinal strip, an opening, and one horizontal bridge, which may be similar to the longitudinal strip 305, the opening 307, and the horizontal bridge 308 in FIG. 3 , respectively. Additionally, the third mesh detector element 710 may include a charge-carrying region 716. The charge-carrying region 716 may have a configuration similar to the longitudinal strip (e.g., may include a metal layer disposed over an implant layer and an oxide opening) and may act to collect and transfer charge carriers. The third mesh detector element 710 may include the charge-carrying region 716 due to the third mesh detector element's proximity to the guard ring 704 and the linear edge 703 being angled inward with respect to the x-axis. Because the third mesh detector element 710 is positioned close to the guard ring 704, a first edge 720 of the third mesh detector element may be angled with respect to the y-axis. Additionally, the first edge 720 may be sloped relative to the second edge 722 of the third mesh detector element 710, which may further reduce the surface area of ​​the third mesh detector element below the x-axis. In this manner, the slope of the first edge 720 may cause the charge bearing region 716 to not have a sufficient shape and / or surface area to accommodate one or more openings within the charge bearing region 716.

[0080] The second mesh detector element 708 and the third mesh detector element 710 may include signal readout traces 712. The signal readout traces 712 may be located at ends of the mesh detector elements opposite the direction of incidence of X-ray photons. For example, end 724 of detector array 700 may be configured to receive X-ray radiation (e.g., X-ray photons) within the semiconductor layer. Furthermore, the signal readout traces 712 may be configured to transmit electrical signals from the second mesh detector element 708 and the third mesh detector element 710 to an image processing unit. Although not shown in FIG. 7 , the first mesh detector element 706 may also include signal readout traces.

[0081] It should be understood that the detector array 700 can include four or more mesh detector elements disposed within the semiconductor region 714 of the detector array. Mesh detector elements disposed near the center of the detector array 700 can be similar to the first mesh detector element 706. Mesh detector elements disposed near additional corners of the detector array 700 can be similar to the third mesh detector element 710. Additionally, mesh detector elements disposed near the guard ring 704 can include one or more slanted edges, which may cause one or more portions of the mesh detector element to lack sufficient area to contain openings. Openings may be omitted in portions of the mesh detector element where sufficient area is not available, and in such cases, one or more rows of openings may include more or fewer openings than other rows. The mesh detector elements may be arranged in rows and / or columns to maximize the surface area of ​​the semiconductor layer covered by the mesh detector elements. In this manner, the number of dead / inactive regions of the detector array 700 can be reduced by the orientation and configuration of the mesh detector elements within the detector array.

[0082] 8 shows a portion of a second example detector array 800. The detector array 800 may include an outer edge 802 and a guard ring 804 having similar functions to the outer edge 702 and guard ring 704 of FIG. 7. The guard ring 804 may be disposed between the outer edge 802 and the mesh detector elements of the detector array 800. In this manner, the guard ring 804 may collect leakage current occurring at the outer edge 802 and prevent the leakage current from unduly affecting the detector array 800.

[0083] Detector array 800 may include mesh detector elements 806. Mesh detector elements 806 may be triangular and may include rounded outer corners (such as corner 808). The rounded outer corners may reduce the risk of voltage breakdown of mesh detector elements 806. Furthermore, the triangular shape of mesh detector elements 806 allows the mesh detector elements to be positioned closer to guard ring 804. Furthermore, in some examples, mesh detector elements 806 may include outer corners that are not rounded (e.g., two straight lines meeting at an angle).

[0084] The detector array 800 can be configured to receive x-rays at a first end 810 and transmit electrical signals from a second end 812. In some examples, the mesh detector elements 806 can transmit electrical signals through signal readout traces (such as signal readout traces 316 in FIG. 3 ).

[0085] Mesh detector element 806 may include longitudinal strips, openings, and horizontal bridges, which may be similar to longitudinal strips 305, openings 307, and horizontal bridges 308, respectively, of FIG. 3. The longitudinal strips, openings, and horizontal bridges of mesh detector element 806 may have suitable dimensions that differ from those of previously described mesh detector elements (e.g., first mesh detector element 302 of FIG. 3 or first mesh detector element 706 of FIG. 7). For example, each horizontal bridge of mesh detector element 806 may be shorter than the horizontal bridges of first mesh detector element 706 of FIG. 7, and / or the ratio of the total area of ​​the openings to the area of ​​the mesh detector element may be greater than that of first mesh detector element 302 of FIG. 3.

[0086] The mesh detector element 806 may include regions without apertures (such as charge-carrying regions 814), which may serve a similar function as the charge-carrying regions 716 in FIG. 7 . The charge-carrying regions 814 may be configured similarly to longitudinal strips (e.g., may include a metal layer disposed over an implant layer and oxide apertures) and may act to collect and / or transport charge carriers. The charge-carrying regions 814 may result from the triangular shape of the mesh detector element 806 and its proximity to the guard ring 804. A first edge 816 of the mesh detector element 806 may be angled relative to a second edge 818 of the mesh detector element. Due to the angle of the first edge 816, the mesh detector element 806 may not have sufficient surface area for one or more apertures along the first edge. As such, the charge-carrying regions 814 may not have a sufficient shape and / or sufficient surface area to accommodate one or more additional apertures. Similar to the third mesh detector element 710 of FIG. 7, the mesh detector elements 806 can include more openings in some rows than others due to the slope of the first edges 816 .

[0087] It should be understood that the detector array 800 can include multiple mesh detector elements arranged within the guard ring 804 of the detector array. Mesh detector elements arranged near the guard ring 804 may include one or more slanted edges and therefore may not include a constant number of diode openings and / or longitudinal strips along the length of the mesh detector element. Mesh detector elements arranged near the center of the detector array 800 may not include slanted edges and therefore may be similar to the first mesh detector element 302 of FIG. 3 . The mesh detector elements may be arranged in rows and / or columns to maximize the surface area of ​​the semiconductor layer covered by the mesh diodes. In this manner, the number of dead / inactive areas of the detector array 800 can be reduced by the orientation and configuration of the mesh detector elements within the detector array.

[0088] The technical effect of a PCCT detector including mesh detector elements composed of longitudinal strips, apertures, and horizontal bridges is that images can be reconstructed with high resolution and low noise. The inclusion of apertures in the mesh detector elements reduces the capacitance of the mesh detector elements, thereby reducing the electronic noise of the PCCT detector. This increases the contrast-to-noise ratio (CNR) for soft tissue contrast imaging and maintains or increases the CNR for material decomposition imaging.

[0089] The present disclosure also supports a medical imaging detector, comprising a mesh detector element formed on a planar surface of a first semiconductor layer, the mesh detector element including a metal layer including a plurality of longitudinal strips, each longitudinal strip disposed on a respective second semiconductor layer of opposite doping polarity to the first semiconductor layer, the second semiconductor layer embedded in the first semiconductor layer, each longitudinal strip separated from adjacent longitudinal strips by a respective opening of a plurality of openings, the metal layer not extending continuously across the width of the mesh detector element. A first embodiment of the detector further includes an oxide layer on the planar surface of the first semiconductor layer, the oxide layer including a plurality of oxide openings, each oxide opening aligned with a respective longitudinal strip. A second embodiment of the detector optionally includes the first embodiment, wherein each longitudinal strip is in surface contact with a respective second semiconductor layer through a respective oxide opening. A third embodiment of the detector optionally includes one or both of the first and second embodiments, wherein the mesh detector element has an overall area defined by a width of the metal layer and a length of the metal layer, and each opening of the plurality of openings has an opening area, and an overall opening area defined by adding together the opening areas is at least 10% of the overall area. A fourth embodiment of the detector optionally includes one or more or each of the first to third embodiments, wherein the plurality of longitudinal strips include first longitudinal strips and second longitudinal strips, and the plurality of openings include a first opening separating the first longitudinal strips from the second longitudinal strips, the first longitudinal strip having a first inner edge extending parallel to a second inner edge of the second longitudinal strip, the first inner edge being connected to the second inner edge through a curved edge of the metal layer. A fifth embodiment of the detector optionally includes one or more of the first to fourth embodiments, wherein the plurality of longitudinal strips includes five longitudinal strips and the plurality of openings includes four openings.A sixth embodiment of the detector optionally includes one or more of the first through fifth embodiments, wherein the plurality of openings includes a first row of openings and a second row of openings separated by a horizontal bridge, and wherein each longitudinal strip of the plurality of longitudinal strips extends continuously along the length of the metal layer from a first end region of the mesh detector element to a second end region of the mesh detector element. A seventh embodiment of the detector optionally includes one or more of the first through sixth embodiments, wherein the mesh detector element includes a signal readout trace at the second end region. An eighth embodiment of the detector optionally includes one or more of the first through seventh embodiments, wherein the mesh detector element is a first mesh detector element of a plurality of mesh detector elements formed on the planar surface of the first semiconductor layer. A ninth embodiment of the detector optionally includes one or more of the first to eighth embodiments, wherein the planar surface of the first semiconductor layer is the first planar surface of the first semiconductor layer, and further includes a common back electrode disposed on a second planar surface of the first semiconductor layer. A tenth embodiment of the detector optionally includes one or more of the first to ninth embodiments, wherein the first semiconductor layer, the common back electrode, and the plurality of mesh detector elements form a first sensor, and the detector includes the first sensor and a plurality of additional sensors, the plurality of additional sensors being positioned such that edges of the first semiconductor layer of the first sensor that are orthogonal to the first and second planar surfaces receive photons of X-ray radiation. An eleventh embodiment of the detector optionally includes one or more of the first to tenth embodiments, wherein the first semiconductor layer is an n-type semiconductor and the second semiconductor layer is a p-type semiconductor.

[0090] The present disclosure also supports a medical imaging detector. The medical imaging detector includes an n-type semiconductor layer, an oxide layer disposed on a first planar surface of the n-type semiconductor layer, a common back electrode disposed on a second planar surface of the n-type semiconductor layer, and a plurality of mesh detector elements formed on the first planar surface of the n-type semiconductor layer, each mesh detector element including a metal layer including a plurality of longitudinal strips, each longitudinal strip disposed on a respective p-type semiconductor layer embedded in the n-type semiconductor layer and separated from adjacent longitudinal strips by a respective opening of the mesh detector element. In a first embodiment of the detector, each longitudinal strip is in surface contact with a respective p-type semiconductor layer through a respective oxide opening. In a second embodiment of the detector, optionally including the first embodiment, each mesh detector element has an overall area defined by the width and length of the metal layer, each opening of the plurality of openings having an opening area, and the overall opening area defined by adding up the respective opening areas is 10% of the overall area. A third embodiment of the detector optionally includes one or both of the first and second embodiments, wherein the plurality of longitudinal strips includes a first longitudinal strip and a second longitudinal strip, and the plurality of openings includes a first opening separating the first longitudinal strip from the second longitudinal strip. A fourth embodiment of the detector optionally includes one or more of the first through third embodiments, wherein the plurality of longitudinal strips includes five longitudinal strips, and the plurality of openings includes four openings. A fifth embodiment of the detector optionally includes one or more of the first through fourth embodiments, wherein the plurality of openings includes a first row of openings and a second row of openings separated by a horizontal bridge, and each longitudinal strip of the plurality of longitudinal strips extends continuously along the length of the metal layer.

[0091] The present disclosure also supports a medical imaging detector, the medical imaging detector including an n-type semiconductor layer having a perimeter defined by a top edge, a first side edge, a second side edge, and a bottom edge, the top edge configured to receive photons of x-ray radiation, the first side edge meeting the top edge at a first corner of the n-type semiconductor layer, and a plurality of mesh detector elements formed on a first planar surface of the n-type semiconductor layer, a first mesh detector element disposed at the first corner, the first mesh detector element including a first metal layer including a first plurality of longitudinal strips, each first longitudinal strip being a first metal layer of the plurality of mesh detector elements. and a second mesh detector element disposed closer to the second side edge than the first mesh detector element, the second mesh detector element including a second metal layer including a second plurality of longitudinal strips, each second longitudinal strip separated from an adjacent second longitudinal strip by a respective second opening of the second mesh detector element's plurality of second openings, the first plurality of openings including a second mesh detector element having a different number of openings than the second plurality of openings. In a first embodiment of the detector, the first plurality of openings include a first row of openings and a second row of openings separated by a first horizontal bridge, and the second plurality of openings include a third row of openings and a fourth row of openings separated by a second horizontal bridge.

[0092] Alternatively stated, an edge-on detector array for a diagnostic imaging system is provided. The edge-on detector array for a diagnostic imaging system includes an n-type semiconductor layer and a plurality of mesh detector elements disposed on a planar surface of the n-type semiconductor layer. Each mesh detector element includes a plurality of detector strips extending along the length of the mesh detector element. Further, each detector strip includes a metal layer at least partially covering the p-type semiconductor layer and separated from adjacent detector strips by openings. In this case, the p-type semiconductor layer and the metal layer do not extend continuously along the width of the mesh detector element.

[0093] When introducing elements of various embodiments of the present disclosure, the articles “a,” “an,” and “the” are intended to mean that there are one or more of the element. The terms “first,” “second,” and the like do not denote order, quantity, or importance, but rather are used to distinguish one element from another. “Comprising,” “including,” “having,” and the like are intended to be inclusive and mean that there may be additional elements other than the listed elements. As used herein, terms such as “connected,” “coupled,” and the like refer to one object (e.g., a material, element, structure, member, etc.) being connected to or coupled to another object, regardless of whether the one object is directly connected to or coupled to the other object, or whether there are one or more intervening objects between the one object and the other object. In addition, it should be understood that references to “one embodiment” or “an embodiment” of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the referenced features.

[0094] In addition to the modifications described above, many other variations and alternative structures may be devised by those skilled in the art without departing from the spirit and scope of the present description, and the claims are intended to cover such modifications and structures. Thus, while the above information has been described in particular detail with respect to what are presently considered to be the most practical and preferred embodiments, it will be apparent to those skilled in the art that many modifications, including but not limited to, in form, function, method of operation, and use, are possible without departing from the principles and concepts described herein. Furthermore, the examples and embodiments herein are meant to be merely illustrative in all respects and should not be construed as limiting in any manner. [Explanation of symbols]

[0095] 100 PCCT System 102 Gantry 104 X-ray source 106 X-ray radiation beam 108 detector array 110 Image Processing Unit 112 Subject 114 Tables 200 Imaging System 202 detector elements 204 specimens 206 Center of rotation 208 Control Mechanism 210 X-ray controller 212 Gantry motor controller 214 Data Acquisition System (DAS) 216 Computing Devices 218 Storage device 220 Operator Console 226 Table Motor Controller 230 Configurator 232 Display device 300 mesh detector elements 301 Detector Array 302 first mesh detector element 303 Second Mesh Detector Element 304 first longitudinal strip 305 Longitudinal Strip 306 First Opening 307 Opening 308 Horizontal Bridge 310 dashed line 312 first end 314 Second End 316 Signal Readout Trace 318 Metal layer 404 Implant Layer 406 Opening 408 Outer corner 410 Inside corner 411 Inside corner 412 first end region 413 Inner Edge 414 First Transition Zone 416 points 418 Second Transition Zone Within 500 502 Semiconductor layer 504 Common back electrode 506 Oxide layer 508 areas 510 Separation area 602 First Edge 604 Second Edge 700 detector array 701 Corner 702 outer edge 703 Straight Edge 704 Guard Ring 706 First Mesh Detector Element 708 Second Mesh Detector Element 710 third mesh detector element 712 Signal Readout Trace 714 Semiconductors 716 Charge carrying region 720 First Edge 722 Second Edge 724 End 800 detector array 802 outer edge 804 Guard Ring 806 mesh detector elements 810 first end 812 Second End 814 Charge carrying region 816 First Edge 816 First Edge 818 Second Edge 900 detector array 901 Detector 902 Edge 910 First Line 912 Second Line 914 Third Line 916 Fourth Line 918 5th line 920 Printed Circuit Board (PCB) 922 Arrow Column 924 926 Wirebond 1000 areas 1002 Guard Ring 1006 pixel area 1008 First Column 1010 Second column 1011 Semiconductor layer 1012 plane 1014 First detector 1016 Second detector 1018 pixels

Claims

1. 1. A medical imaging detector, comprising: a mesh detector element formed on a planar surface of a first semiconductor layer, the mesh detector element including a metal layer including a plurality of longitudinal strips, each longitudinal strip disposed on a respective second semiconductor layer of opposite doping polarity to the first semiconductor layer, the second semiconductor layer being embedded in the first semiconductor layer, each longitudinal strip separated from an adjacent longitudinal strip by a respective opening of a plurality of openings, the metal layer not extending continuously across a width of the mesh detector element; the plurality of longitudinal strips include a first longitudinal strip and a second longitudinal strip, the plurality of openings include a first opening separating the first longitudinal strip from the second longitudinal strip, the first longitudinal strip having a first inner edge extending parallel to a second inner edge of the second longitudinal strip, the first inner edge being connected to the second inner edge through a curved edge of the metal layer.

2. 10. The detector of claim 1, further comprising an oxide layer on a planar surface of the first semiconductor layer, the oxide layer including a plurality of oxide openings, each oxide opening aligned with a respective longitudinal strip.

3. 3. The detector of claim 2, wherein each longitudinal strip is in surface contact with a respective second semiconductor layer through a respective oxide opening.

4. 2. The detector of claim 1, wherein the mesh detector element has an overall area defined by a width of the metal layer and a length of the metal layer, and each opening of the plurality of openings has an aperture area, and the overall aperture area defined by adding the aperture areas together is at least 10% of the overall area.

5. The detector of claim 1 , wherein the plurality of longitudinal strips includes five longitudinal strips and the plurality of apertures includes four apertures.

6. 2. The detector of claim 1, wherein the plurality of openings includes a first row of openings and a second row of openings separated by a horizontal bridge, and wherein each longitudinal strip of the plurality of longitudinal strips extends continuously along a length of the metal layer from a first end region of the mesh detector element to a second end region of the mesh detector element.

7. The detector of claim 6 , wherein the mesh detector elements include signal readout traces at the second end regions.

8. 2. The detector of claim 1, wherein the mesh detector element is a first mesh detector element of a plurality of mesh detector elements formed on a planar surface of the first semiconductor layer.

9. 9. The detector of claim 8, wherein the planar surface of the first semiconductor layer is a first planar surface of the first semiconductor layer, and further comprising a common backside electrode disposed on a second planar surface of the first semiconductor layer.

10. 10. The detector of claim 9, wherein the first semiconductor layer, the common backside electrode, and the plurality of mesh detector elements form a first sensor, the detector including the first sensor and a plurality of additional sensors positioned such that an edge of the first semiconductor layer of the first sensor that is orthogonal to the first planar surface and the second planar surface receives photons of X-ray radiation.

11. 2. The detector of claim 1, wherein the first semiconductor layer is an n-type semiconductor and the second semiconductor layer is a p-type semiconductor.

12. 1. A medical imaging detector, comprising: an n-type semiconductor layer; an oxide layer disposed on a first planar surface of the n-type semiconductor layer; a common backside electrode disposed on a second planar surface of the n-type semiconductor layer; and a plurality of mesh detector elements formed on the first planar surface of the n-type semiconductor layer, each mesh detector element including a metal layer including a plurality of longitudinal strips, each longitudinal strip disposed on a respective p-type semiconductor layer embedded in the n-type semiconductor layer, each longitudinal strip separated from an adjacent longitudinal strip by a respective one of a plurality of openings in the mesh detector element; Including, The detector, wherein the plurality of openings includes a first row of openings and a second row of openings separated by a horizontal bridge, and each longitudinal strip of the plurality of longitudinal strips extends continuously along the length of the metal layer.

13. 13. The detector of claim 12, wherein each longitudinal strip is in surface contact with a respective p-type semiconductor layer through a respective oxide opening.

14. 13. The detector of claim 12, wherein each mesh detector element has an overall area defined by a width of the metal layer and a length of the metal layer, and each opening of the plurality of openings has an aperture area, and the overall aperture area defined by adding together the aperture areas is 10% of the overall area.

15. 13. The detector of claim 12, wherein the plurality of longitudinal strips includes a first longitudinal strip and a second longitudinal strip, and the plurality of openings includes a first opening separating the first longitudinal strip from the second longitudinal strip.

16. The detector of claim 12 , wherein the plurality of longitudinal strips includes five longitudinal strips and the plurality of openings includes four openings.

17. 1. A medical imaging detector, comprising: an n-type semiconductor layer having a perimeter defined by a top edge, a first side edge, a second side edge, and a bottom edge, the top edge configured to receive photons of x-ray radiation and the first side edge meeting the top edge at a first corner of the n-type semiconductor layer; a plurality of mesh detector elements formed on a first planar surface of the n-type semiconductor layer, a first mesh detector element disposed in the first corner, the first mesh detector element including a first metal layer including a first plurality of longitudinal strips, each first longitudinal strip separated from an adjacent first longitudinal strip by a respective first opening of a plurality of first openings of the first mesh detector element; and a second mesh detector element disposed closer to the second side edge than the first mesh detector element, the second mesh detector element including a second metal layer including a second plurality of longitudinal strips, each second longitudinal strip separated from an adjacent second longitudinal strip by a respective second opening of the second mesh detector element's plurality of second openings, the plurality of first openings including a different number of openings than the plurality of second openings; a plurality of mesh detector elements, including a detector.

18. 18. The detector of claim 17, wherein the plurality of first apertures includes a first row of apertures and a second row of apertures separated by a first horizontal bridge, and the plurality of second apertures includes a third row of apertures and a fourth row of apertures separated by a second horizontal bridge.

Images