ONE-PIECE DEVICE FOR DETECTING PARTICLES WITH SEMICONDUCTOR MATERIAL
20220246669 · 2022-08-04
Assignee
- UNIVERSITE D'AIX MARSEILLE (Marseille Cedex 07, FR)
- Centre National de la Recherche Scientifique (Paris Cedex 16, FR)
Inventors
Cpc classification
H01L31/118
ELECTRICITY
International classification
Abstract
A one-piece device for detecting particles with semiconductor material includes a substrate layer and at least one additional layer disposed on a first face of the substrate layer so as to form at least one first detector comprising a first space charge zone through which a beam of particles passes and first collector means for charge carriers produced by this passage. It further includes at least one other additional layer disposed on a second face of the same substrate layer, opposite the first face, so as to form at least one second detector comprising a second space charge zone through which the beam of particles also passes and second collector means for charge carriers produced by this passage.
Claims
1. A one-piece device for detecting particles with semiconductor material comprising: a substrate layer formed in the semiconductor material, at least one additional layer formed in at least one of the semiconductor material in at least one conductive material disposed on a first face of the substrate layer so as to form at least a first detector comprising: a first electronic space charge zone through which a first axis of the detection device to be followed by a particle beam passes, and first collector means for collecting charge carriers produced by the particle beam passing through the first space charge zone, wherein the device further comprises at least one other additional layer formed in at least one of the semiconductor material and in at least one conductive material disposed on a second face of the substrate layer, opposite to the first face, so as to form at least a second detector independent of the first detector from the substrate layer and comprising: a second electronic space charge zone, through which a second axis of the detection device parallel to the first axis and to be followed by the particle beam passes, and second collector means for collecting charge carriers produced by the particle beam passing through the second space charge zone, the second collector means being electrically insulated from the first collector means to ensure independence of the first and second detectors.
2. The one-piece particle detection device according to claim 1, wherein: the at least one additional layer comprises one of: a first additional layer formed in the at least one conductive material disposed directly on the first face of the substrate layer, and a second additional layer formed in the semiconductor material by epitaxy from the substrate layer, the first additional layer formed in the at least one conductive material being disposed indirectly on the first face of the substrate layer via the second additional layer formed in the semiconductor material, so as to form an anode and a cathode of a first Schottky diode, and the at least one other additional layer comprises one of: a third additional layer formed in the at least one conductive material disposed directly on the second face of the substrate layer, and a fourth additional layer formed in the semiconductor material by epitaxy from the substrate layer, the third additional layer formed in the at least one conductive material being disposed indirectly on the second face of the substrate layer via the fourth additional layer formed in the semiconductor material, so as to form an anode and a cathode of a second Schottky diode.
3. The one-piece particle detection device according to claim 1, wherein: the at least one additional layer comprises at least one first additional layer portion formed in the semiconductor material with opposite doping type to that of the substrate layer and a first additional layer formed in said at least one conductive material of which at least one conductor is in contact with the at least one first additional layer portion formed in the semiconductor material, so as to form a first PIN diode, and the at least one other additional layer comprises at least one second additional layer portion formed in the semiconductor material with an opposite doping type to that of the substrate layer and a second additional layer formed in the at least one conductive material of which at least one conductor is in contact with the at least one second additional layer portion formed in the semiconductor material, so as to form a second PIN diode.
4. The one-piece particle detection device according to claim 1, comprising two buffer layers respectively formed by epitaxy from the first and second faces of the substrate layer.
5. The one-piece particle detection device according to claim 11, comprising two holes hollowed out in the semiconductor material on either face of the substrate layer about the first and second parallel axes to be followed by the particle beam respectively.
6. The one-piece particle detection device according to claim 1, wherein the substrate layer is n++ doped.
7. The one-piece particle detection device according to claim 1, wherein a plurality of first detectors and a plurality of second detectors are formed.
8. The one-piece particle detection device according to claim 1, wherein the at least one second detector is formed to have diodes angularly offset at right angles to corresponding diodes of the at least one first detector about a common direction of the first and second parallel axes to be followed by the particle beam.
9. The one-piece particle detection device according to claim 1, wherein the substrate layer common to the detectors is formed in the semiconductor material.
10. The one-piece particle detection device according to claim 1, wherein the first and second parallel axes are coincident.
Description
[0056] The invention will be better understood with the aid of the following description, which is given only by way of example and is made with reference to the attached drawings wherein:
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[0065] The one-piece particle detection device 100 shown schematically in cross-section in
[0066] The device 100 further includes an additional top layer of metallic conductive material disposed directly on a first top face 104 of the substrate layer 102. This additional top layer is made of two disjoint metallic conductors 106 and 108, i.e., electrically insulated from each other, one of which, for example the one with reference 106, performs an anode function and the other of which, for example the one with reference 108, performs a cathode function.
[0067] A first Schottky diode forming a first detector is thus formed by forming a first space charge zone 110 in the substrate 102 under its first top surface 104 between the two conductors 106 and 108. This first space charge zone 110 is passed through by a main axis of the detection device 100 intended to be followed by a particle beam, as illustrated in
[0068] The device 100 further includes another additional bottom layer of metallic conductive material disposed directly on a second bottom surface 112 of the substrate layer 102. This other additional bottom layer is made of two disjoint metallic conductors 114 and 116, one of which, for example the one with reference 114, performs an anode function and the other of which, for example the one with reference 116, performs a cathode function.
[0069] A second Schottky diode forming a second detector is thus formed by forming a second space charge zone 118 in the substrate 102 under its second face 112 between the two conductors 114 and 116. By symmetry of the device 100, this second space charge zone 118 is passed through by the same principal axis followed by the particle beam as the first space charge zone 110. The anode 114 and the cathode 116, thus forming respectively a Schottky contact and an ohmic contact of the second Schottky diode, constitute second collector means for collecting charge carriers produced by the particle beam passing through the second space charge zone 118.
[0070] It should be noted that in order for the two space charge zones to form correctly on either face of the substrate 102, the distance L2 between the two collectors of each Schottky diode must be smaller than L1.
[0071] It is also worth noting the extreme simplicity of this one-piece Schottky diode detection device 100. While allowing a dual detection by two independent detectors as required more and more often, it makes it possible to preserve very good properties of transparency to the particles, of compactness and of manufacturing costs.
[0072] It should also be noted that in the embodiment of
[0073] The one-piece particle detection device 200 shown schematically in cross-section in
[0076] The substrate 202 is for example, like the substrate 102, n++ doped. The additional top layer 220 is, for example, n− doped and epitaxially formed above the substrate layer 202 in the same semiconductor material, with its free upper face 204 contacting the collectors 206 and 208. Similarly, the additional bottom layer 222 is, for example, n− doped and epitaxially formed below the substrate layer 202 in the same semiconductor material, with its free lower face 212 contacting the collectors 214 and 216.
[0077] The interest of this embodiment compared to the previous one is to extend the space charge zones 210 and 218 in the thickness of the semiconductor material without, however, making the charges disappear in the substrate 202 at the expense of the cathodes 208 and 216, for example. A compromise must be found between the n-doping of the layers 220 and 222, the thickness of this n− doping and the distance between the electrodes 206 and 208 or 214 and 216. This compromise is within the reach of the skilled person.
[0078] It should be noted that alternatively the substrate layer 202 could be p++ doped, the additional top layer 220 p− doped and the additional bottom layer 222 p− doped also.
[0079] It should also be noted that in the embodiment shown in
[0080] The one-piece particle detection device 300 shown schematically in cross-section in
[0083] Like the previous one, it comprises a top layer of metallic conductive material, directly in contact with the free upper face 304 of the additional top layer 320 made of semiconductor material, constituted by two disjointed metallic conductors 306 and 308 forming respectively the anode and the cathode of a first Schottky diode with space charge zone 310, as well as a bottom layer of metallic conductive material, directly in contact with the free lower face 312 of the additional bottom layer 322 of semiconductor material, consisting of two disjointed metallic conductors 314 and 316 forming respectively the anode and the cathode of a second Schottky diode with a space charge zone 318.
[0084] The substrate 302 is for example, like the substrate 202, n++ doped. The top buffer layer 324 is, for example, n+ doped and epitaxially formed over the substrate layer 302 in the same semiconductor material. The additional top layer 320 is, for example, like the additional top layer 220, n− doped and formed by epitaxy over the top buffer layer 324 in the same semiconductor material. Similarly, the bottom buffer layer 326 is, for example, n+ doped and epitaxially formed below the substrate layer 302 in the same semiconductor material. The additional bottom layer 322 is, for example, n-doped and epitaxially formed below the bottom buffer layer 326 in the same semiconductor material.
[0085] The advantage of this embodiment over the previous one is to avoid the upwelling of impurities from the n++ doped substrate 302 to the additional top and bottom layers 320 and 322 of semiconductor material during the epitaxy process. The intermediate n+ doping of the two buffer layers 324 and 326 allows this. It should be noted that although this is a known manufacturing method in the semiconductor field for the manufacture of power devices, it is not the case for the manufacture of detection devices.
[0086] It should also be noted that alternatively the substrate layer 302 could be p++ doped, the additional top layer 320 p− doped, the additional bottom layer 322 also p-doped and the two buffer layers 324, 326 p+ doped.
[0087] It should further be noted that in the embodiments of
[0088] The one-piece particle detection device 400 shown schematically in cross-section in
[0096] The one-piece particle detection device 400 shown schematically in cross-section in
[0099] As a result, the Schottky contacts mentioned above are replaced by ohmic contacts, so that the first diode forming the first detector and the second diode forming the second detector become p-doped PIN diodes (generally noted as PI diodes).
[0100] It should be noted that alternatively the substrate layer 402 could be p++ doped, the additional top layer 420 p− doped, the additional bottom layer 422 also p− doped, the two buffer layers 424, 426 p+ doped, and the two additional layer portions n+ doped. This would result in two detectors formed by two n-doped PIN diodes (generally noted as NI diodes).
[0101] The one-piece particle detection device 500 shown schematically in cross-section in
[0102] However, it differs from the previous one in that: [0103] it has locally another additional top layer portion 532, formed in the semiconductor material by epitaxy with n++ doping and interposed between the additional top layer 520 of n− doped semiconductor material and the cathode 508 so that the latter is not in direct contact with the n-doped semiconductor material, and [0104] it has locally another additional bottom layer portion 534, formed in the semiconductor material by epitaxy with n++ doping and interposed between the additional bottom layer 522 of n− doped semiconductor material and the cathode 516 so that the latter is not in direct contact with the n− doped semiconductor material.
[0105] As a result, the first diode forming the first detector and the second diode forming the second detector become p- and n-doped PIN diodes (generally noted as PIN diodes). This allows a better collecting of charge carriers.
[0106] It should be noted that alternatively the substrate layer 502 could be p++ doped, the additional top layer 520 p− doped, the additional bottom layer 522 also p− doped, the two buffer layers 524, 526 p+ doped, the two additional layer portions 528, 530 n+ doped, and the two other additional layer portions 532, 534 p++ doped. This would result in two detectors formed by two n- and p-doped PIN diodes (generally noted as NIP diodes).
[0107] The one-piece particle detection device 600 shown schematically in cross-section in
[0108] However, it differs from the previous one in that: [0109] its additional top layer portion 628, p+ doped and interposed between the additional top layer 620 of n− doped semiconductor material and the anode 606, has box doping in the space charge zone 610, i.e., by lateral junction termination extension (lateral JTE) in the space charge zone 610, [0110] its additional bottom layer portion 630, p+ doped and interposed between the additional bottom layer 622 of n− doped semiconductor material and the anode 614, has box doping in the space charge zone 618, i.e. by lateral junction termination extension (lateral JTE) in the space charge zone 618, [0111] a plurality of portions of an top oxide layer 636 are added to the upper face of the additional top layer 620 of semiconductor material or to that of the additional top layer portions 628, 632 formed of the same semiconductor material, in particular between the anode 606 and the cathode 608, and [0112] a plurality of portions of a bottom oxide layer 638 are added to the lower face of the additional bottom layer 622 of semiconductor material or to that of the additional bottom layer portions 630, 634 formed of the same semiconductor material, particularly between the anode 614 and the cathode 616.
[0113] The box doping of the p+ doped additional layer portions 628, 630 provides spatial control of the space charge zones 610, 618 by smoothing the electrostatic fields generated therein, i.e., creating softer field lines so as to avoid field spikes. The boxes are doped according to the same type as the additional layer portion 628 or 630 that they extend. Their more precise configuration and their distribution according to the configurations and arrangements of the other elements of the device are within the reach of the skilled person.
[0114] The oxidation of the above-mentioned upper and lower faces, particularly between the anodes and cathodes of the two PIN diodes, makes it possible to neutralize dangling bonds and the resulting electrical disturbances that can be created by manufacturing.
[0115] Furthermore, as in the previous embodiments, it is entirely possible to invert the n and p doping of the different layers of semiconductor material of the one-piece device 600.
[0116] It should also be noted that in the embodiments of
[0117] The one-piece particle detection device 700 shown schematically in cross-section in
[0118] It further includes top 736 and bottom 738 oxide layer portions like the one-piece device 600 of
[0119] It also has the following additional features: [0120] a hole 740 is hollowed out from the lower face of the oxide/semiconductor layer stack 738, 722, 726, 702, 724, 720, 728 from the oxide layer 738 to a certain depth in the substrate layer 702 opposite the conductor 706, [0121] a hole 742 is hollowed out from the upper face of the oxide/semiconductor layer stack 736, 720, 724, 702, 726, 722, 730 from the oxide layer 736 to a certain depth in the substrate layer 702 opposite the conductor 716, [0122] a conductive layer 714 is disposed at the bottom, sidewall, and flange (i.e., under the oxide layer 738) of the hole 740, and [0123] a conductive layer 708 is disposed on the bottom, sidewall, and flange (i.e., on the oxide layer 736) of the hole 742.
[0124] An advantage of this configuration is to thin the part of the one-piece device 700 likely to be crossed by the incident particle beam and thus to improve its transparency, by providing two holes hollowed out in the semiconductor material on either face of the substrate layer 702 around main axes intended to be followed by the particle beam.
[0125] By a first appropriate choice of the thicknesses and dimensions of the various components of the one-piece device 700: [0126] the conductive layers 706 and 708 form the anode and cathode, respectively, of a first charge carrier collecting PIN diode, the corresponding space charge zone 710 being formed, like the space charge zone 410 of the one-piece device 400, in the thickness of the additional top layer 720 of semiconductor material between the anode 706 and cathode 708, and [0127] the conductive layers 716 and 714 form the anode and cathode, respectively, of a second charge carrier collecting PIN diode, the corresponding space charge zone 718 being formed, like the space charge zone 418 of the one-piece device 400, in the thickness of the additional bottom layer 722 of semiconductor material between the anode 716 and cathode 714.
[0128] By a second appropriate choice of the thicknesses and dimensions of the various components of the one-piece device 700: [0129] the conductive layers 706 and 714 respectively form the anode and cathode of a first charge carrier collecting PIN diode, the corresponding space charge zone 710′ being then offset to the left, contrary to the previous configuration, in the thickness of the additional top layer 720 of semiconductor material between the anode 706 and the cathode 714, and [0130] the conductive layers 716 and 708 respectively form the anode and the cathode of a second charge carrier collecting PIN diode, the corresponding space charge zone 718′ being then offset to the right, contrary to the previous configuration, in the thickness of the additional bottom layer 722 of semiconductor material between the anode 716 and the cathode 708.
[0131] According to this second choice of configuration, it is important that the lateral dimensions of the one-piece device 700 are sufficiently small compared to the thickness of the incident beam so that the two space charge zones 710′ and 718′ are passed through by this same beam.
[0132] Furthermore, as in the previous embodiments, it is entirely possible to invert the n and p doping of the different semiconductor material layers of the one-piece device 700.
[0133] For the sake of simplicity, the preceding embodiments have been presented on the basis of one anode and one cathode per face of the one-piece device, so as to constitute one charge carrier collecting detector per face, whereas it is quite possible to multiply the number of detectors by multiplying the number of anodes and cathodes per face.
[0134] The one-piece particle detection device 800 shown schematically in cross-section in
[0135] Like the devices of
[0145] With regard to the respective thicknesses of the various aforementioned layers, it should be noted that the scale is not respected in the schematic illustration of
[0146] On the upper face 804 of the other additional top layer 832 n++ doped and the top central layer portion 828 p+ doped, both formed in the additional top layer 820 of n− doped semiconductor material, are disposed: [0147] a top central layer 806 of conductive metal forming an anode, for example of Ni/Ti/Al/Ni material with a thickness of approximately 100 nm, in the form of a disk with an outer flange arranged above and in contact only with the top central layer portion 828 of p+ doped semi-conductor material, [0148] a top peripheral layer 808 of conductive metal as a cathode, for example of Ti/Ni material with a thickness of about 100 nm, in the form of a ring with an inner flange arranged above and in contact only with the other additional top layer 832 of n++ doped semiconductor material, and [0149] a top oxide layer 836 extending into the ring-shaped interior volume delimited by the respective flanges of the anode 806 and the cathode 808, for example made of SiO2 material and with a thickness of 1 to 3 μm corresponding approximately to the height of the flanges.
[0150] Thus, the additional top layer 820 of n− doped semiconductor material actually extends from the top buffer layer 824 to the top oxide layer 836 in the volume left free between the top central layer portion 828 and the top ring-shaped layer 832.
[0151] On the lower face 812 of the other additional bottom layer 834 n++ doped and the bottom central layer portion 830 p+ doped, both formed in the additional bottom layer 822 of n− doped semiconductor material, are disposed: [0152] a bottom central layer 814 of conductive metal forming an anode, for example of Ni/Ti/Al/Ni material with a thickness of approximately 100 nm, in the form of a disk with an outer flange arranged below and in contact only with the bottom central layer portion 830 of p+ doped semiconductor material, [0153] a bottom peripheral layer 816 of conductive metal as a cathode, for example of Ti/Ni material with a thickness of about 100 nm, in the form of an inner flanged ring arranged below and in contact only with the other additional bottom layer 834 of n++ doped semiconductor material, and [0154] a lower oxide layer 838 extending into the ring-shaped interior volume delimited by the respective flanges of the anode 814 and cathode 816, for example made of SiO2 material and with a thickness of 1 to 3 μm corresponding approximately to the height of the flanges.
[0155] Thus, the additional bottom layer 822 of n− doped semiconductor material actually extends from the bottom buffer layer 826 to the bottom oxide layer 838 in the volume left free between the bottom central layer portion 830 and the bottom ring-shaped layer 834.
[0156] As a result, a first top space charge zone 810 is formed below the top central layer portion 828 within the thickness of the layer 820 and about the axis of symmetry D. Similarly, a second bottom space charge zone 818 is formed above the bottom center layer portion 830 within the thickness of the layer 822 and about the axis of symmetry D. The arrangement of the aforementioned successive layers of semiconductor material allows the field lines to be laterally bent and the charge carriers to be collected by means of anode and cathode pairs arranged on the same upper or lower face of the one-piece device 800. In particular, since the space charge zones do not extend in depth beyond layers 820 and 822, the substrate 802 no longer performs more than a mechanical support function.
[0157] It is then very easy to realize multiple detectors per face of the one-piece device 800 by insulating multiple conductive angular sectors in the disks 806, 814 and rings 808, 816. For example, by insulating four disk quarters in each of the conductive disks 806, 814 and four corresponding ring quarters in each of the conductive rings 806, 814, four top PIN diodes and four bottom PIN diodes are insulated. With this configuration, it is further possible to design an angular offset about the D-axis of symmetry and passing through of the incident beam between the upper and lower diodes, including a right angle offset as required in some device classes or standards for dual detection.
[0158] It should be noted that, alternatively, it is possible to imagine other arrangements for multiplying the number of detectors on each face of a one-piece detection device according to the present invention. In particular, a matrix or other arrangement of a number N of detectors extending laterally on each face makes it possible to envisage several local dual detections in the section of the incident particle beam.
[0159] It appears clearly that a one-piece detection device such as one of those described above allows for a reduction in size and cost while improving the transparency of the dual detection that is increasingly required for safety reasons in particle emission systems.
[0160] Another advantage appears more clearly in the embodiment of
[0161] It should further be noted that the invention is not limited to the various embodiments described above.
[0162] In particular, all the detectors considered in the above-described embodiments are Schottky or PIN diodes. However, other semiconductor material detectors can be considered, such as transistors (for example CMOS, JFET or bipolar).
[0163] Furthermore, there may be an asymmetry of detectors arranged on either face of the substrate of a one-piece detecting device according to the present invention, such as different diodes, diodes and transistors, etc.
[0164] It will be more generally apparent to the person skilled in the art that various amendments can be made to the above-described embodiments in light of the teaching just disclosed. In the above detailed presentation of the invention, the terms used should not be construed as limiting the invention to the embodiments set forth in the present description, but should be construed to include all equivalents the anticipation of which is within the reach of the person skilled in the art by applying their general knowledge to the implementation of the teaching just disclosed to them.