Device and multi-zone sensor for monitoring a radiation or particle beam
The multi-zone sensor addresses the limitations of SiC devices by isolating the detection zone from the substrate, enhancing sensitivity and dynamic response, enabling precise monitoring of beam intensity, position, and shape with reduced interference.
Patent Information
- Authority / Receiving Office
- WO · WO
- Patent Type
- Applications
- Current Assignee / Owner
- SENSIC GMBH
- Filing Date
- 2025-11-25
- Publication Date
- 2026-06-04
AI Technical Summary
Existing radiation or particle beam monitoring devices, particularly those made of Silicon Carbide (SiC), suffer from high thermal noise, parasitic capacitances, and funneling effects, limiting sensitivity and dynamic response, and are costly.
A multi-zone sensor comprising a semiconductor substrate with an epitaxial layer, an insulating layer, and metal electrodes, featuring a detection zone isolated from the substrate, reduces thermal noise and funneling effects, enhancing sensitivity and dynamic response by isolating the detection zone and using multiple sensors to detect distinct beam portions.
The device achieves improved signal-to-noise ratio and response speed, allowing precise monitoring of beam intensity, position, and shape with reduced interference, and can measure short pulsed beams effectively.
Smart Images
Figure IB2025062040_04062026_PF_FP_ABST
Abstract
Description
[0001] TITLE: Device and multi-zone sensor for monitoring a radiation or particle beam DESCRIPTION
[0002] Technical Field
[0003] The present invention relates to a device and a multi-zone sensor suitable for monitoring a radiation or particle beam. Such a device and such a multi-zone sensor find particular application in determining the intensity, position and shape of said beam.
[0004] Description of the prior art
[0005] In the state of the art, it is known to produce "in-transmission" monitoring devices for radiation or particle beams, for example, ionizing beams of X-rays or gamma rays, ions, subatomic particles, electrons, protons or positrons, capable of working in harsh conditions, with high temperatures and intense particle irradiations. Examples of the use of such devices are sterilization processes, new radiotherapy processes and processes in nuclear plants.
[0006] For the aforementioned applications, devices made of single-crystal or polycrystalline diamond have been widely studied and used, having good transparency to the ionizing beam and high thermal conductivity.
[0007] However, it is known in the state of the art that such devices are associated with very high costs and limitations on the size of the samples. Furthermore, diamond devices have a high level of impurities and strong physical limitations to doping. This has therefore led to the search for solutions capable of overcoming the intrinsic criticalities of diamond, while guaranteeing the same performance.
[0008] Monitoring devices for radiation or particle beams made of alternative semiconductor materials, for example Silicon Carbide (SiC), have therefore been devised. A particular example of such devices is represented by the so-called XBPM devices, from the English X-ray Beam Position Monitors. Such devices can be of the non-destructive-peripheral type, capable of detecting only the tails of the ionizing X- ray beam, of the destructive-axial type, such as for example fluorescent screens suitable for being traversed by the ionizing beam, and of the non-destructive-axial type, also traversable by the ionizing beam but having a high transparency to it, thus minimally disturbing the beam itself.
[0009] It is worth noting that non-destructive-peripheral type XBPM devices have poor lateral resolution and high sensitivity to noise, whereas destructive-axial type devices have high interference with the ionizing beam, which entails a strong limitation on the use of such devices. Non-destructive-axial type devices in SiC, on the other hand, can present a sufficiently high thermal conductivity and transparency to the ionizing beam, which results in reduced interference with it. Such devices allow for measuring ionizing beams by absorbing only a small fraction thereof, thus reducing any degradation effects, including scattering.
[0010] Non-destructive-axial type devices in Silicon Carbide, also known as membrane devices, generally consist of a substrate of semiconductor material, an epitaxial layer superimposed thereon, and thin upper and lower metal plates, having a thickness, for example, of 200 nanometers, arranged in a sandwich around the substrate and the epitaxial layer. In particular, such devices have a reduced thickness portion, called a membrane, at a pit formed in the substrate, which is adapted to be traversed by the radiation or particle beam with minimal interference on the beam. Examples of such membrane devices are shown in the documents “Ion beam evaluation of silicon carbide membrane structures intended for particle detectors” J. Pallon et al. Journal of Nuclear Instruments and Methods in Physics Research B 371, 132 (2016), “Silicon carbide X-ray beam position monitors for synchrotron applications”, Nida et Al., Journal of Synchrotron Radiation (2019), “Radiation Hardness Study of Silicon Carbide Sensors under High-Temperature Proton Beam Irradiations”, Medina et. Al., Micromachines (2023), and "Single-Ion Counting with an Ultra- Thin-Membrane Silicon Carbide Sensor", Sangregorio et Al., Materials (2023).
[0011] Although the aforementioned devices represent a more favorable solution compared to the further solutions of the known art described above, they still have some limitations. In particular, such devices have considerable membrane dimensions, such that there is high thermal noise due to a dark, or leakage, current and high parasitic capacitances, which limit the sensitivity and dynamic response of the device. In addition, such devices have a disadvantageous alteration of the response of the device itself to the radiation or particle beam, which is caused by the presence of a contribution from the substrate. Indeed, despite optimizing the position of the membrane device with respect to the radiation or particle beam so that only the membrane portion is traversed by it, it is not always possible to avoid the so-called funneling effect, i.e., an alteration and worsening of the quality of the signal generated by the device in relation to the detection of the radiation or particle beam.
[0012] SUMMARY OF THE INVENTION
[0013] In this context, the technical task of the present invention is to provide a device and a multi-zone sensor for monitoring a radiation or particle beam that can overcome the drawbacks of the known art.
[0014] In particular, the object of the present invention is to realize a device and a multi-zone sensor for monitoring a radiation or particle beam that allow for optimizing the detection of the beam, increasing sensitivity and dynamic response, and reducing the funneling effect and any alterations or distortions of the signal generated by the device in relation to the detected radiation or particle beam.
[0015] The specified technical task and the specified objects are substantially achieved by a device and a multi-zone sensor comprising the technical features described in one or more of the appended claims.
[0016] Advantages of the invention
[0017] The device according to the present invention is able to monitor the intensity, position and, optionally, the shape of a radiation or particle beam by means of a defined, reduced and suitably isolated beam detection zone with respect to the known solutions, thus being able to: eliminate the contribution of the so-called funneling effect, i.e., excluding contributions to the signal generated from edge zones of the detection zone influenced by the substrate, and reduce the area, and thus the electrical capacitance, of the device itself. This reduction allows the device to be more performant in terms of response speed (allowing the measurement of very short pulsed beams, less than 10 nanoseconds) and to improve, even by several orders of magnitude, the signal-to-noise ratio (SNR).
[0018] While the device, i.e., the single-zone sensor of the present invention, allows for determining the total intensity, or power, of the radiation or particle beam, the multi-zone sensor combines two or more of said devices in order to detect distinct portions of the radiation or particle beam, so as to acquire sufficient information to define not only the total intensity, but also the position of the radiation or particle beam and to detect any displacements thereof.
[0019] BRIEF DESCRIPTION OF THE DRA WINGS The features and advantages of the present invention will become apparent from the following detailed description of a possible practical embodiment, illustrated by way of non-limiting example in the set of drawings, in which:
[0020] - Figure 1 shows a monitoring device of a known type, in particular a Schottky device, according to the prior art;
[0021] - Figure 2 shows a sectional view of a first embodiment of a device according to the present invention;
[0022] - Figure 3 shows a sectional view of a second embodiment of a device according to the present invention;
[0023] - Figure 4 shows a sectional view of a third embodiment of a device according to the present invention;
[0024] - Figure 5a shows a sectional view of a fourth or fifth embodiment of a device according to the present invention;
[0025] - Figure 5b shows a sectional view of a sixth embodiment of a device according to the present invention;
[0026] - Figure 6a shows a top view of the first embodiment of the device of Figure 2;
[0027] - Figure 6b shows a top view of the fourth embodiment of the device of Figure 5;
[0028] - Figure 6c shows a top view of a fifth embodiment of the device according to the present invention;
[0029] - Figure 7 shows a sectional view of a first embodiment of a multi-zone sensor according to the present invention;
[0030] - Figure 8 shows a sectional view of a second alternative embodiment of the multi-zone sensor of Figure 7; - Figure 9 shows a top view of the first embodiment of the multi-zone sensor of Figure 7;
[0031] - Figure 10 shows a top view of a third embodiment of the multi -zone sensor according to the present invention;
[0032] - Figure 11 shows a top view of a fourth embodiment of the multi-zone sensor according to the present invention;
[0033] - Figure 12 shows a top view of a fifth embodiment of a multi-zone sensor according to the present invention.
[0034] DETAILED DESCRIPTION
[0035] The present invention relates to a device 1 for monitoring a radiation or particle beam A emitted along a propagation direction X-X. It should be noted that the present device 1 is particularly advantageous for monitoring an ionizing beam, and specifically an X-ray beam, but is also effective in monitoring, for example, a beam of gamma rays, ions, subatomic particles, electrons, protons or positrons. It should be observed that the present device 1 is also effective in monitoring non-ionizing beams, for example of visible light or infrared radiation, on the basis of their interaction with the device 1 and the consequent transfer of energy to the device 1 described below.
[0036] The device 1 of the present invention comprises a substrate 2 of semiconductor material, preferably silicon carbide, which extends along the propagation direction X- X between an upper surface 2a and an opposite lower surface 2b.
[0037] Advantageously, silicon carbide has numerous advantages in terms of cost, chemical-mechanical-electrical resistance, speed of electrical response, signal-to- noise ratio, and uniformity of electrical current. The device 1 further comprises an epitaxial layer 3, also of semiconductor material, grown in superposition on the substrate 2 along the propagation direction X- X.
[0038] The epitaxial layer 3 defines a respective upper surface 3a and a lower surface 3b, opposite the upper surface 3a, along the propagation direction X-X. The lower surface 3b is therefore placed in contact with the upper surface 2a of the substrate 2.
[0039] The device 1 comprises an insulating layer 6 of dielectric material, such as for example silicon oxide (SiO2), having an upper surface 6a and a lower surface 6b opposite the upper surface 6a along the propagation direction X-X.
[0040] The insulating layer 6 is arranged on the epitaxial layer 3, such that the lower surface 6b of the insulating layer 6 is in contact with the upper surface 3a of the epitaxial layer 3.
[0041] According to a preferred aspect, the insulating layer 6 has a thickness of at least 10 nanometers, more preferably greater than 50 nanometers, even more preferably greater than 100 nanometers.
[0042] According to a preferred aspect, the insulating layer 6 has a resistivity value equal to or greater than 1E9 Ohm* / ??, more preferably equal to or greater than 1E14 Ohm*m. Advantageously, in the detection of the radiation or particle beam A, the insulating layer 6 is capable of electrically isolating from the radiation or particle beam A all the remaining components of the device 1 underlying it.
[0043] The device 1 comprises a pit 4 which extends along the propagation direction X-X at least between the lower surface 2b and the upper surface 2a of the substrate 2. It is therefore noted that the pit 4 extends for the entire thickness of the substrate 2. Optionally, the pit 4 may extend partially along the epitaxial layer 3, at least at the lower surface 3b thereof. Within the scope of the present invention, pit 4 is understood to mean a depression, also known as an etching pit or etch pit, obtained through a process of removing material layers, for example by electrochemical etching of the substrate 2. In more detail, the electrochemical etching involves the oxidation of the semiconductor material and subsequent removal of the oxide by immersion in an acid-based solution, for example a hydrofluoric acid-based solution.
[0044] The process of forming the pit 4 is known in the technical field and within the grasp of a person skilled in the art, and will therefore not be further described.
[0045] The device 1 also comprises a detection zone 7 configured to detect the radiation or particle beam A. In more detail, the detection zone 7 is configured to be traversed through its entire thickness by the radiation or particle beam A.
[0046] The detection zone 7, once traversed by the radiation or particle beam A, is configured to generate a current signal as a function of the intensity, position and / or shape of the radiation or particle beam A itself.
[0047] According to a preferred aspect, the generated current signal is detectable by means of detection devices. It should be observed that the detection devices for monitoring devices for a radiation or particle beam are known in the technical field and will therefore not be further described.
[0048] The detection zone 7 comprises a depression 8 which extends along the propagation direction X-X through the entire thickness of the insulating layer 6, i.e., between the upper surface 6a and the lower surface 6b of the insulating layer 6, at the pit 4. In other words, the insulating layer 6 preferably has an opening 9 at the detection zone 7, such that the depression 8 is defined by said opening 9 and is laterally delimited by the insulating layer 6. According to one aspect, the depression 8 has a characteristic dimension smaller than the characteristic dimension of the pit 4. Preferably, the characteristic dimension of the depression 8 is between 0.001 mm and 10 mm, more preferably between 0.1 mm and 1 mm.
[0049] In the context of the present description, characteristic dimension is intended as a diameter or a length along a transverse direction, preferably perpendicular, to the propagation direction X-X.
[0050] For example, if the depression 8 and / or the pit 4 have a circular section, the characteristic dimension can be the respective diameter.
[0051] According to a further aspect, the depression 8 has a concavity with an opposite orientation with respect to the pit 4 along the propagation direction X-X.
[0052] The device 1 comprises a pair of metal layers, and in particular comprises an upper metal layer 5a and a lower metal layer 5b spaced apart from each other along the propagation direction X-X. Preferably, the upper and lower metal layers 5a, 5b are made of aluminum. More preferably, the upper and lower metal layers 5a, 5b have a thickness of less than 200 nm.
[0053] Is should be noted that the pair of metal layers acts as electrodes through which it is possible to measure the current signal generated by the device 1 during the detection of the radiation or particle beam A.
[0054] The lower metal layer 5b is superimposed on the pit 4, and thus on a portion of the lower surface 3b of the epitaxial layer 3, and at least partially on the lower surface 2b of the substrate 2. The upper metal layer 5a is instead superimposed on the detection zone 7 and at least partially on the insulating layer 6.
[0055] In accordance with a first embodiment, shown in Figure 2 and 6a, the upper metal layer 5a is superimposed directly on a portion of the upper surface 3a of the epitaxial layer 3, not covered by the insulating layer 6. The detection zone 7 is therefore defined by said portion of the epitaxial layer 3, at the depression 8, and by the respective upper and lower metal layers 5a, 5b superimposed thereon.
[0056] According to a preferred aspect, shown in the accompanying figures 2-4, the substrate 2 and the epitaxial layer 3 comprise respective n type doped layers, having impurity concentrations, i.e., doping entities or levels, differing by at least one order of magnitude.
[0057] In more detail, the substrate 2 comprises a first doped layer, preferably an n+ type doped layer, having an impurity concentration equal to or greater than 1E17 cm3, while the epitaxial layer 3 comprises a second doped layer, preferably an n- type doped layer, having an impurity concentration equal to or lower than 5E16 cm3. Preferably, the impurities of the first and second doped layers preferably comprise nitrogen or phosphorus atoms.
[0058] In accordance with a second embodiment, shown in Figure 3, the device 1 comprises a first intermediate layer 10 superimposed on the upper surface 3a of the epitaxial layer 3 at least at the detection zone 7. According to this embodiment, the upper metal layer 5a is placed in contact with the first intermediate layer 10 at the detection zone 7.
[0059] Preferably, the first intermediate layer 10 comprises a third doped layer, preferably a p+ type doped layer, having impurities different from the first and second doped layers. More preferably, the impurities of the third doped layer comprise aluminum atoms. Even more preferably, the third doped layer has an impurity level equal to or greater than IE 17 cm3.
[0060] In accordance with a third embodiment, shown in Figure 4, the device 1 comprises a second intermediate layer 11 superimposed on the lower surface 3b of the epitaxial layer 3 at least at the detection zone 7. According to this embodiment, the lower metal layer 5 is placed in contact with the second intermediate layer 11 at the pit 4.
[0061] Preferably, the second intermediate layer 11 comprises a fourth doped layer, preferably an n+ type doped layer, having the same impurities as the first and second doped layers. The fourth doped layer preferably has an impurity concentration equal to or greater than IE 17 cm3.
[0062] It is worth noting that the first and second intermediate layers 10, 11 allow for obtaining a more robust and more reproducible semiconductor-semiconductor junction.
[0063] It is also worth noting that the presence of the second intermediate layer 11 allows for improving the interface properties between the epitaxial layer 3 and the lower metal layer 5b, as any roughness at the interface between them could influence the generation of the signal by the device 1.
[0064] In addition, the second intermediate layer 11 introduces an asymmetry in the device 1 that allows it to operate even at 0 V, unlike traditional devices, for example Schottky / Schottky devices.
[0065] According to an aspect of the invention, the substrate 2 has a thickness along the propagation direction X-X between 200 and 500 pm, more preferably between 300 and 400 pm.
[0066] According to the same aspect, the epitaxial layer 3 has a thickness along the propagation direction X-X between 0.1 and 100 pm, preferably between 1 and 20 pm.
[0067] Still according to the same aspect, the insulating layer 6 has a thickness along the propagation direction X-X equal to or greater than 10 nm, preferably equal to or greater than 100 nm. Furthermore, the upper metal layer 5a preferably has a thickness along the propagation direction X-X between 10 and 500 nm, more preferably equal to 75 nm. The lower metal layer 5b, instead, preferably has a thickness along the same direction between 20 and 500 nm, more preferably equal to 100 nm.
[0068] If present, the first intermediate layer 10 and / or the second intermediate layer 11 preferably have a thickness along the propagation direction between 0.1 and 2 pm, more preferably between 0.1 and 0.5 pm.
[0069] It is noted that the total dimension of the device 1, in the various embodiments, does not exceed 2 mm in thickness.
[0070] It is worth noting that the device 1 thus described has a substrate 2 capable of providing adequate robustness to the entire structure, and at the same time a detection zone 7 defining a membrane independent of the substrate 2 and mechanically anchored to the substrate 2, which has a high transparency to the radiation or particle beam A. This membrane is therefore self-standing with respect to the substrate 2.
[0071] In greater detail, the absence of the substrate 2 in the detection zone 7 and the presence of the insulating layer 6 in the remaining part of the device 1 allows for excluding at least part of the contribution of the substrate 2, and in optimal conditions the total contribution thereof, during the detection of the radiation or particle beam A, thus reducing the impact that said substrate has on the electrical properties of the device 1. In particular, this leads to a drastic increase in the electrical response speed and the signal-to-noise ratio. It is observed from experimental data that the device 1 of the present invention has an electrical response speed increased by a factor of 10, or more, compared to prior art devices.
[0072] By doing so, the interference of the device with the radiation or particle beam A is also significantly reduced, and thus the alterations or distortions, for example due to the funneling effect, of the signal generated during the detection of the radiation or particle beam A.
[0073] It is therefore to be noted that the device 1 thus realized defines a nondestructive-axial type membrane sensor optimized with respect to the known solutions.
[0074] In accordance with a fourth embodiment, shown in Figure 5a and 6b, the device 1 defines at least one through-opening 12 extending along the propagation direction X-X at the detection zone 7. The through-opening 12 is configured to be traversed by a portion of the radiation or particle beam A. In other words, only a portion of the radiation or particle beam A is detected, namely the one intercepted by the detection zone 7, while the remaining portion, passing through the through-opening 12, is not intercepted by the device 1.
[0075] It is observed that the dimension of the through-opening 12 is defined as a function of the area of the detection zone 7 necessary for the detection of the portion of the radiation or particle beam A of interest, and of the dimension of the remaining portion of the radiation or particle beam A not to be detected. In other words, the through-opening 12 must be able to allow the passage through it of the portion of the radiation or particle beam to be excluded from detection, and at the same time must allow for obtaining an area of the detection zone 7 sufficient to detect the portion of the radiation or particle beam A of interest, as better detailed in the remainder of the present description.
[0076] According to the fourth embodiment, the detection zone 7 is configured to detect only a portion of the radiation or particle beam A corresponding to the tails of said beam. In more detail, the through-opening 12 is configured to allow the passage through the through-opening 12 itself of the central portion of the radiation or particle beam A. In accordance with a fifth embodiment, shown in Figure 6c, alternative to the fourth embodiment, the detection zone 7 comprises a central portion 7a and one or more through-openings 12 adapted to radially delimit the central portion 7a of the detection zone 7.
[0077] Preferably, the central portion 7a of the detection zone 7 is connected by means of connection portions 7b to a peripheral portion of the detection zone 7 and / or to the epitaxial layer 3.
[0078] It is observed that according to this embodiment, the central portion 7a of the detection zone 7 is configured to detect the central portion of the radiation or particle beam A, while the tails of said beam pass through the one or more through-openings 12.
[0079] It is worth noting that the fourth and fifth embodiments are particularly advantageous as they allow for obtaining regions without any beam-device interaction. This allows the device 1 of the present invention to be used also in applications that provide, for example, real-time monitoring of so-called soft X-rays (having a photon energy below lOOOeV), for which even the use of very thin membrane sensors, for example having a thickness of 100 nanometers, would induce excessive disturbances and / or interference due to absorption in the radiation or particle beam A.
[0080] In accordance with a sixth embodiment of the invention, shown in Figure 5b, the epitaxial layer 3 comprises one or more recesses 13 extending from the upper surface 3a of the epitaxial layer 3 through the thickness of the epitaxial layer 3 along the propagation direction X at the depression 8. Alternatively, or in addition, the epitaxial layer 3 comprises one or more protrusions, not shown, projecting from the upper surface 3 a of the epitaxial layer 3 along the propagation direction X. In other words, in these embodiments of the preceding paragraph, the epitaxial layer 3 has an inhomogeneous thickness along a direction transverse to the propagation direction X.
[0081] It is noted that such recesses and / or protrusions are obtained by means of specific processing of the epitaxial layer 3.
[0082] Advantageously, such recesses or protrusions allow, in combination with the presence of the insulating layer 6 and the pit 4 described above, to further isolate the detection zone 7 of the device 1 with respect to the substrate 2.
[0083] Still advantageously, the recesses or protrusions allow for obtaining an improvement in the sensitivity of the device 1 to the radiation or particle beam through a focusing or concentration of the local electric field.
[0084] A further object of the present invention is a multi-zone sensor 20 for monitoring a radiation or particle beam A, and specifically for detecting the position and / or any displacements, and optionally the shape, of the radiation or particle beam A.
[0085] The multi-zone sensor 20 comprises two or more devices 1 according to the present description, operatively connected to each other.
[0086] According to a preferred aspect, the devices 1 of the multi-zone sensor 20 are electrically connected to each other.
[0087] Preferably, the substrates 2 of the devices 1 of the multi-zone sensor 20 are made in a common substrate.
[0088] By way of example, Figures 9, 10 and 11 show a multi-zone sensor 20 comprising four devices 1 connected to each other.
[0089] The detection zones 7 of two or more devices 1 are adjacent to each other and are separated from each other by means of a respective separation zone 21. In more detail, the detection zone 7 of each device 1 is configured to detect a portion of the radiation or particle beam A distinct from the portions detected by the detection zones 7 of the other devices 1.
[0090] It is well to observe that the device 1 of the present invention acts as a singlezone sensor, and is capable of measuring the intensity of the radiation or particle beam A. The assembly of multiple single-zone sensors, integrated into the present multizone sensor 20, allows instead to also acquire information useful for performing the detection of the position of the radiation or particle beam A and / or of any displacements of the beam at least along a plane substantially perpendicular to the propagation direction X-X, by means of combination and coupling of the signals generated by each device 1.
[0091] Optionally, the multi-zone sensors 20 can have a high complexity, for example comprising a high number n of devices 1 in an n x n configuration, so as to allow the acquisition of information useful for determining the shape of the radiation or particle beam A.
[0092] Such multi-zone sensors are particularly advantageous, for example, in determining any distortions or deteriorations in the quality of the beam following the use of mirrors for the reflection of the radiation or particle beam.
[0093] By way of example, Figure 12 shows a multi-zone sensor 20 comprising 8 x 8 devices 1.
[0094] According to one aspect, the detection zone 7 of each device is connected by means of a respective conductive track, not shown, to an external pad suitable for allowing the detection, i.e., the reading, of the signal generated by the device 1.
[0095] In accordance with a first embodiment, shown in Figure 7 and 9, the separation zone 21 comprises a trench 21a adapted to separate two adjacent detection zones 7. In other words, the depressions 8 of the detection zones 7 are spaced apart from each other by the trench 21a along a transverse direction, preferably orthogonal, to the propagation direction X-X.
[0096] In accordance with a second embodiment of the multi-zone sensor 20, alternative to the aforesaid first embodiment and shown in Figure 8, the separation zone 21 comprises a protrusion 21b extending along the propagation direction X-X. The protrusion 21b is formed at least partially by the insulating layer 6. Preferably, the protrusion 21b is adapted to surround and delimit at least in part each detection zone 7. In other words, the depressions 8 of two adjacent detection zones 7 are separated from each other by the protrusion 21b.
[0097] It is worth noting that this embodiment is particularly advantageous, as it allows for isolating the separation zone 7 of each device 1, making it independent from the further separation zones, thus improving the detection of the respective portion of the radiation or particle beam A.
[0098] According to a third embodiment, shown in Figure 10, the multi -zone sensor 20 comprises a through-opening 22 arranged between the detection zones 7 of the devices 1. In more detail, the detection zones 7 surround and delimit the through- opening 22.
[0099] The through-opening 22 is configured to be traversed by a portion of the radiation or particle beam A. In other words, the through-opening 22 allows for excluding from detection a certain portion of the radiation or particle beam A, and in particular the central portion thereof, and instead allows the detection zones 7 to intercept the remaining portions of the radiation or particle beam A, i.e., portions of the tails of the radiation or particle beam A. It is observed that the dimension of the through-opening 22 of the multi-zone sensor 20 must be defined as a function of both the area of each detection zone necessary for the detection of the respective portion of the radiation or particle beam A, and of the remaining portion of the radiation or particle beam A to be excluded from detection.
[0100] According to a fourth embodiment of the multi-zone sensor 20, alternative to the third embodiment and shown in figure 11, the multi-zone sensor 20 comprises a central detection area, defined by respective terminal portions of the detection zones 7 of the adjacent devices 1, and one or more through-openings 22 adapted to radially delimit the central detection area of the multi-zone sensor 20. The through-openings 22 are configured to be traversed by a respective portion of the radiation or particle beam A.
[0101] Preferably, the terminal portions of the detection zones 7 that form the central detection area of the multi-zone sensor 20 are connected by means of connection portions to respective central portions of the detection zones 7 and / or to the epitaxial layer 3 of the respective devices 1.
[0102] It is observed that according to this embodiment, the central detection area of the multi-zone sensor 20 is configured to detect the central portion of the radiation or particle beam A, while the tails of said beam pass through the one or more through- openings 22.
[0103] The same advantages described above for the fourth and fifth embodiments of the device 1 are also obtained by the third and fourth embodiments of the multi-zone sensor 20 described herein.
Claims
CLAIMS1. A device (1) for monitoring a radiation or particle beam (A) emitted along a propagation direction (X-X), comprising:- a substrate (2) of semiconductor material extending between an upper surface (2a) and a lower surface (2b) opposite the upper surface (2a) along the propagation direction (X-X);- an epitaxial layer (3) superimposed on the substrate (2) along the propagation direction (X-X) and defining a respective upper surface (3a) opposite a lower surface (3b) which contacts the upper surface (2a) of the substrate (2);- a pit (4) extending along the propagation direction (X-X) at least between the lower surface (2b) and the upper surface (2a) of the substrate (2);- a pair of upper and lower metal layers (5a, 5b) spaced apart from each other along the propagation direction (X-X), the lower metal layer (5b) being superimposed at least partially on the pit (4) and at least partially on the lower surface (2b) of the substrate (2);- an insulating layer (6) of dielectric material arranged on the upper surface (3a) of the epitaxial layer (3) and defining, along the propagation direction (X-X), an upper surface (6a) and an opposite lower surface (6b) which is placed in contact with the epitaxial layer (3);- a detection zone (7) configured to detect the radiation or particle beam (A) and comprising a depression (8) extending along the propagation direction (X-X) between the upper surface (6a) and the lower surface (6b) of the insulating layer (6) at the pit (4), wherein the detection zone (7) defines a membrane independent from the substrate (2) and mechanically anchored to the substrate (2), and wherein the upper metal layer(5a) is superimposed on the detection zone (7) and at least partially on the insulating layer (6).
2. The device (1) according to claim 1, wherein the insulating layer (6) has at least one opening (9) at the detection zone (7) so that the depression (8) of the detection zone (7) is delimited by the insulating layer (6).
3. The device (1) according to claim 1 or 2, wherein the insulating layer (6) has a resistivity value equal to or greater than 1E9 Ohm*m, preferably equal to or greater than 1E14 Ohm*m.
4. The device (1) according to any one of claims 1 to 3, wherein the insulating layer (6) has a thickness, along the propagation direction (X-X), equal to or higher than 10 nm, preferably equal to or higher than 100 nm.
5. The device (1) according to any one of claims 1 to 4, wherein the pit (4) has a concavity having an opposite orientation with respect to the depression (8) of the detection zone (7).
6. The device (1) according to any one of claims 1 to 5, wherein the substrate (2) comprises a first doped layer having a concentration of impurities equal to or higher than 1E17 cm3, the epitaxial layer (3) comprising a second doped layer having a concentration of impurities equal to or lower than 5E16 cm3, the impurities of the first and second doped layers preferably comprising nitrogen or phosphorus atoms.
7. The device (1) according to claim 6, comprising a first intermediate layer (10) superimposed on the upper surface (3a) of the epitaxial layer (3) at least at the detection zone (7), the first intermediate layer (10) comprising a third doped layer having different impurities with respect to the first and the second doped layer.
8. The device (1) according to claim 7, wherein the third doped layer has a level of impurities equal to or greater than 1E17 cm3, the impurities of the third doped layer preferably comprising aluminum atoms.
9. The device (1) according to claim 7 or 8, comprising a second intermediate layer (11) superimposed on the lower surface (3b) of the epitaxial layer (3) at least at the detection zone (7), the second intermediate layer (11) comprising a fourth doped layer having the same impurities of the first and the second doped layer, the fourth doped layer preferably having a concentration of impurities equal to or higher than 1E17 cm3.
10. The device (1) according to any one of claims 1 to 9, defining at least one through- opening (12) extending along the propagation direction (X-X) at the detection zone (7), said through-opening (12) being configured to be passed through by a portion of the radiation or particle beam (A).
11. The device (1) according to any one of claims 1 to 10, wherein the epitaxial layer (3) comprises one or more recesses (13) and / or one or more protrusions extending along the propagation direction (X) from the upper surface (3a) of the epitaxial layer(3) adapted to allow the local increase of the electric field generated between the upper metal layer (5a) and the lower metal layer (5b).
12. A multi-zone sensor (20) for monitoring a radiation or particle beam (A), comprising two or more devices (1) according to any one of claims 1 to 11, operatively connected to each other, wherein:- the detection zones (7) of the devices (1) are adjacent to each other and separated from each other by means of a respective separation zone (21), and- the detection zone (7) of each device (1) is configured to detect a portion of the radiation or particle beam (A) which is distinct from the portions detected by the detection zones (7) of the other devices (1).