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  • 权利要求
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    • 专利摘要:
    The invention relates to a photodetector comprising a photoelectric conversion structure made of a semiconductor material and, on a photoreceptive surface of the conversion structure, a stack of first (21) and second (23) diffracting elements, the second element being above the first element, wherein: the first element (21) comprises at least one stud (21a) of an optical index material nor laterally surrounded by a region (21b) of a material of optical index n2 different from ni; the second element (23) comprises at least one stud (23a) of a material of optical index n3 laterally surrounded by a region (23b) of a material of optical index n4 different from n3; the studs (21a, 23a) of the first and second elements are substantially aligned vertically; and the differences in optical indices n1-n2 and n3-n4 are of opposite signs.
    公开号:FR3036851A1
    申请号:FR1554878
    申请日:2015-05-29
    公开日:2016-12-02
    发明作者:Laurent Frey；Michel Marty
    申请人:Commissariat a lEnergie Atomique CEA；STMicroelectronics SA；Commissariat a lEnergie Atomique et aux Energies Alternatives CEA；
    IPC主号:
    专利说明:

    [0001] B14203 - DD15287JB - 13-GR4-1144 1 QUANTUM HIGH-PERFORMANCE PHOTODETECTOR Field The present application relates to the field of semiconductor photodetectors, and more particularly photodiode photodetectors, used for example as pixels of an image sensor. , or as single-photon avalanche diodes. DESCRIPTION OF THE PRIOR ART FIG. 1 represents, in a simplified and partial manner, two side-by-side photodetectors of a set of photodetectors constituting, for example, an image sensor. Each photodetector comprises a semiconductor structure 1 for converting photons into electron-hole pairs. The structure 1 may include junctions (not shown) between semiconductor regions of opposite conductivity types for storing the photogenerated electrons. In a complete photodetector, there is furthermore one or more reading transistors (not shown) for transferring the electrons. PCT patent application WO2012 / 032495 discloses that, when the lateral dimensions of the illuminated surface or photo-receptor surface (the upper surface in FIG. 1) of a photodetector are small, of the order of the wavelength X of light that the photodetector is intended to capture, or wavelength of operation, there is a problem in introducing the light into the photodetector. Thus, the quantum yield of such photodetectors is low. This patent application proposes, for increasing the quantum yield of the photodetector, to have on its photoreceptive surface a single pad 2 whose lateral dimensions are smaller than the lateral dimensions of the photoreceptive surface and the operating wavelength of the photodetector. FIG. 2 is a simplified and partial representation of the detector portion of a single photon avalanche diode photodetector, commonly referred to as SPAD ("Single Photon Avalanche Diode"). In such a photodetector, there is a structure consisting of a semiconductor layer 10, for example N-type, clamped between two semiconductor layers 12 and 13 of the opposite type. The problem is that the layer 10 is, in modern technologies, very thin, typically of a thickness of the order of 1 to 1.5 pin. It is in this layer 10 that the useful conversion of photons into electron-hole pairs must take place, whereas it is known that, in the case of silicon and for infrared radiation, the layer in which to create the electron pairs holes has a thickness greater than 10 pin, to hope to obtain a conversion rate of photons higher than 90%. Thus, the efficiency (or conversion rate) of a SPAD photodetector manufactured by current technologies is only of the order of 5 to 7%. In order to improve this efficiency and not to lose reflected light, an antireflection structure is provided above the semiconducting upper layer 12, alternately comprising a layer of low-index silicon oxide material 14 and a layer of higher-grade material. index 15 in silicon nitride. An upper protective layer 16, made of silicon oxide, overcomes the antireflection structure. Thus, there is a problem in absorbing as many photons as possible in small photodetectors such as those shown in FIG. 1, and in photodetectors in which the semiconductor layer of the photon-collector is The conversion of photons into electron-hole pairs is thin, such as that shown in FIG. 2. More generally, this problem is more or less important in all semiconductor photodetectors.
    [0002] It will be appreciated that in small photodetectors or SPAD photodetectors even a small increase in the quantum efficiency or absorption rate of the useful part of the photodetector is in practice extremely important for the detection of low light. intensity. Thus, a 1 to 5% efficiency gain will be considered a significant gain by the user. SUMMARY Thus, an embodiment provides a photodetector comprising a photoelectric conversion structure of a semiconductor material, and on a photoreceptive surface of the conversion structure, a stack of first and second diffracting elements, the second element being above the first element, wherein the first element comprises at least one pad of a material of optical index n1 laterally surrounded by a region of a material of optical index n2 different from n1; the second element comprises at least one stud made of a material of optical index n3 laterally surrounded by a region of a material of optical index n4 different from n3; the studs of the first and second elements are substantially aligned vertically; and the differences in optical indices ni-n2 and n3-n4 are of opposite signs. According to one embodiment, the pads of the first and second elements have substantially identical lateral dimensions and less than the operating wavelength of the photodetector. According to one embodiment, the dimensions of the photoreceptor surface of the conversion structure are between 0.5 and 1.5 times the operating wavelength of the photodetector, and each of the first and second 3036851 B14203 - DD15287JB - 13 -GR4-1144 4 elements comprises a single stud in the material of optical index ni, respectively n3. According to one embodiment, the dimensions of the photoreceptor surface of the conversion structure are greater than twice the operating wavelength of the photodetector, and each of the first and second elements comprises a periodic array of pads in the optical index material ni, respectively n3. According to one embodiment, in each of the first 10 and second elements, said at least one pad and said region are made of transparent materials at the operating wavelength of the photodetector. According to one embodiment, the photodetector further comprises an intermediate layer of a material transparent to the operating wavelength of the photodetector, between the first and second elements. According to one embodiment, the intermediate layer has a thickness between 40 and 150 nia and has an optical index greater than 2.5.
    [0003] According to one embodiment, in at least one of the first and second elements, the region laterally surrounding said at least one pad of the element is made of a conductive material and is connected to an application terminal of a potential of polarization.
    [0004] According to one embodiment, the differences in optical indices ni-n2 and n3-n4 are, in absolute value, greater than or equal to 1 and preferably greater than or equal to 2. According to one embodiment, in one embodiment first and second elements, said at least one pad and said region are respectively silicon and silicon oxide, and in the other of the first and second elements, said at least one pad and said pad are respectively silicon and silicon.
    [0005] BRIEF DESCRIPTION OF THE DRAWINGS These and other features and advantages will be set forth in detail in the following description of particular embodiments in a non-limiting manner in connection with the Figures. attached, among which: Figure 1, previously described, is a schematic and partial sectional view of two small photodetectors; FIG. 2, previously described, is a schematic and partial sectional view of a SPAD photodetector; Figures 3A and 3B are respectively a sectional view and a top view schematically and partially showing an example of an embodiment of a photodetector; Fig. 4 is a sectional view schematically and partially showing an alternative embodiment of the photodetector of Figs. AA and 3B; and Figs. 5A and 5B are respectively a sectional view and a plan view showing schematically and partially an example of another embodiment of a photodetector. DETAILED DESCRIPTION The same elements have been designated with the same references in the various figures and, in addition, the various figures are not drawn to scale. In the description which follows, when reference is made to absolute position qualifiers, such as the terms "before", "backward", "up", "down", "left", "right", etc., or relative, such as "above", "below", "upper", "lower", "lateral", etc., or to qualifiers for orientation, such as "horizontal", "vertical" , etc., reference is made to the orientation of the figures, it being understood that, in practice, the photodetectors described may be oriented differently. Unless otherwise stated, the terms "approximately", "substantially", and "in the order of" mean within 10%, preferably within 5%. Figures aA and 3B show schematically and partially an example of an embodiment of two photo-5 detectors side by side of a set of photodetectors constituting for example an image sensor. As in the example of FIG. 1, each photodetector comprises a structure 1 for converting photons into electron-hole pairs. The structure 1 is made of a semiconductor material, for example silicon. Two neighboring semiconductor structures 1 are separated, for example, by an insulating region 3. The semiconductor conversion structures 1 are shown very schematically. In practice, each semiconductor structure 1 comprises one or more junctions (not shown) to allow storage of one of the carriers of each photogenerated electron-hole pair (commonly electrons). Each photodetector may further comprise one or more transistors (not shown), in particular to enable the photogenerated charges accumulated in the semiconductor conversion structure 1 to be transferred to a readout circuit (not shown). The case in which the The lateral dimensions of the semiconductor photoconversion structure 1 are of the order of magnitude of the wavelength λ of the light that the photodetector is intended to capture, or the operating wavelength of the sensor. For example, the lateral dimensions of the light exposure surface or photoreceptor surface of each photoreceptor (i.e., the upper surface of structure 1 in the example shown) are between 0, 5 and 1.5 times the operating wavelength X, which is for example between 300 and 3000 nia, and preferably between 600 and 3000 nia. Note that in practice, the sensor can operate in a range comprising several wavelengths. Thus, in the present description, the term "operating wavelength" is understood to mean the smallest wavelength of a wavelength band that the sensor 3036851 B14203 - DD15287JB - 13-GR4-1144 7 is intended to capture . For example, the wavelength band that the sensor is intended to capture has a width of between 1 and 500 rua. On the photoreceptive surface of the semi-conductive structure 1, a vertical stack of two diffracting elements 21 and 23 is arranged. The element 21 comprises a pad 21a made of a material of index n1, disposed on the photoreceptive surface of the structure 1 ( a photoreceptor pad, preferentially centered along the central vertical axis of the photodetector), laterally surrounded by a region 21b in a material of optical index n2 less than ni. The element 23 comprises a stud 23a of a material of index n3, disposed on the upper surface of the diffractive element 21, laterally surrounded by a region 23b of a material of optical index n4 greater than n3.
    [0006] The constituent materials of the pads 21a and 23a and the peripheral regions 21b and 23b are transparent to the operating wavelength X of the photodetector. By "transparent" it is meant that these materials absorb less than 5%, preferably less than 1%, of the radiation at this wavelength.
    [0007] The lateral dimensions of the pads 21a and 23a are smaller than the lateral dimensions of the photoreceptive surface of the semiconductor structure 1 and the operating wavelength of the photodetector. For example, the lateral dimensions of the pads 21a and 23a are between one-tenth and one-half of the operating wavelength of the photodetector. The lateral dimensions of the pads 21a and 23a are preferably substantially identical. In addition, the pads 21a and 23a are preferably substantially aligned vertically, that is to say that in vertical projection, the contours of the pads 21a and 23a are substantially merged. For example, seen from above, the maximum distance between the contours of the pads 21a and 23a is less than 50 rua. Likewise, the lateral dimensions of the peripheral regions 21b and 23b are preferably substantially identical, and the peripheral regions 21b and 23b are preferably substantially vertically aligned (for example with the same tolerance). 50 nm). In the example shown, the studs 21a and 23a have, seen from above, a substantially square shape. However, the embodiments described are not limited to this particular case. More generally, the studs 21a and 23a may have any shape, for example round, square, oval or rectangular. The thickness of each of the elements 21 and 23 is preferably less than the operating wavelength of the photodetector, for example less than half this wavelength. The elements 21 and 23 may have substantially the same thickness or different thicknesses. Preferably, the elements 21 and 23 have the same thickness. Indeed, the tests carried out have shown that better absorption is obtained in the case where the elements 21 and 23 have the same thickness. By way of example, the elements 21 and 23 cover the entire photoreceptive surface of the semiconductor structure 1, it being understood that, as indicated previously, the pads 21a and 21b cover only a part of this photoreceptive surface, the rest being occupied by the peripheral regions 21b and 23b. In the example shown, the peripheral regions 21b of the elements 21 of the different photodetectors of the sensor form a continuous layer coating substantially the entire surface of the sensor with the exception of the parts covered by the pads 21a. Similarly, in this example, the peripheral regions 23b of the elements 23 of the different photodetectors of the sensor form a continuous layer coating substantially the entire surface of the sensor with the exception of the parts covered by the pads 23a. The upper structure formed by the diffractive elements 21 and 23 is for example coated with a protective insulating layer (not shown), for example silicon oxide, which may be surmounted by a filtering layer (no shown) and a microlens proper to each photodetector (not shown).
    [0008] In each of the elements 21 and 23, the optical index difference between the central pad 21a, respectively 23a, and the peripheral region 21b, respectively 23b, is preferably relatively high, for example greater than or equal to 1 and preferably greater than or equal to 2 in absolute value. The optical indices n1 and n4 of the regions of higher indices 21a and 23b of the diffracting elements 21 and 23 are, for example, less than or equal to the optical index nsc of the semiconductor material of the photoconversion structure 1.
    [0009] By way of example, the semiconductor 1 may be silicon with an optical index nsc of the order of 3.6 (in the near infra-red range, ie in a range of lengths wavelength ranging from 800 to 1000 nm). The stud 21a can be made of the semiconductor material of the structure 1 (n1 = nsc). The peripheral region 21b can be made of silicon oxide, with optical index of the order of 1.45, and advantageously correspond (for simplifying the manufacturing process) to a structure of the type customarily used to isolate components formed in the same semiconductor chip and commonly referred to by the acronym STI (Shallow Trench Isolation). The region 23b may be of polycrystalline silicon, with an optical index of the order of 3.5, and advantageously correspond (to simplify the manufacturing process) to a layer usually used to form conductive grids in the field of manufacturing. of MOS transistors. The stud 23a is for example made of silicon oxide. The described embodiments are however not limited to these particular examples. Alternatively, the pad 21a may be polycrystalline silicon, amorphous silicon, silicon carbide, or silicon nitride. In addition, as an alternative, the peripheral region 23b may be amorphous silicon, silicon carbide, or silicon nitride. Alternatively, the materials used to form the pad 21a and the peripheral region 21b of the element 21 on the one hand, and the materials used to form the pad 23a and the 3036851 B14203 - DD15287JB - 13-GR4-1144 Peripheral region 23b on the other hand, can be interchanged. Thus, in the element 21, the index n1 of the stud 21a may be smaller than the index n2 of the region 21b, and in the element 23, the index n3 of the stud 23a may be greater than the index n4 of the region 23b. It will be noted that in the case where the region of high optical index of one and / or the other of the diffracting elements 21 and 23 is in polycrystalline silicon and is formed at the same time as conductive gates of MOS transistors, a thin layer 10 insulating layer, for example a silicon oxide layer of thickness less than 10 nia (corresponding to the gate insulator of the transistors), can interface between this element and the underlying structure, for example between the element 23 and the element 21, or between the element 21 and the structure 1. In addition, a thin spacer of an insulating material, for example a silicon nitride spacer with a thickness of between 30 and 70 nia, The polycrystalline silicon, forming the higher index region of the diffracting element 21 or 23, may laterally separate from the silicon oxide forming the lower index region of the diffracting element. Note that if the regions 23b of the upper diffracting elements 23 form a continuous conductive layer extending over substantially the entire surface of the sensor with the exception of the parts occupied by the pads 23a, provision can be made to connect the layer 23b to a terminal for applying a bias potential, for example in the vicinity of an edge of the sensor. Thus, the layer 23b can, in operation, be polarized so as to reduce the dark currents likely to degrade the performance of the photodetectors. By way of example, the layer 23b can be biased to a positive potential so as to prevent parasitic electrons generated in the vicinity of the upper surface of the semiconductor region 1 from being collected by the photogenerated charge collecting region of the photodetector. .
    [0010] Alternatively, if the regions 21b of the lower diffracting elements 21 form a continuous conductive layer, and if this layer is separated from the semiconductor region 1 by an insulating layer (for example if the layer 21b is made of polycrystalline silicon and is separated from the substrate by a thin layer of silicon oxide), provision can be made, for the same purpose, of connecting the layer 21b to an application terminal of a polarization potential . As will be discussed hereinafter, it is surprisingly found that a structure of the type described in connection with Figs. AA and 3B, suitably sized, significantly increases the conversion efficiency of photons into electron-hole pairs with respect to to a structure of the type shown in FIG. 1. It could have been expected that the arrangement, in the light path, of two successive diffracting elements having substantially complementary arrangements, does not generate any increase in the quantum efficiency by relative to a photodetector not having these elements, or at least results in a lower quantum efficiency increase than that provided by a single diffracting element (as shown in FIG. 1). Indeed, it could have been expected that the beneficial diffraction phenomena in terms of efficiency caused by the first diffracting element are counterbalanced at least in part by the second diffractive element. It is however the opposite that occurs, namely that the stack of the two diffracting elements of complementary arrangements makes it possible to increase by several percent the quantum efficiency with respect to a photodetector with a single diffracting element.
    [0011] Figure 4 is a sectional view schematically and partially showing an alternative embodiment of the photodetectors of Figures aA and 3B. The structure of Figure 4 comprises the same elements as the structure of Figures aA and 3B. These elements will not be detailed again.
    [0012] The structure of FIG. 4 differs from the structure of FIGS. 3B essentially in that it comprises an additional layer 41 made of a material that is transparent to the operating wavelength of the photodetector. separating the diffractive element 21 from the diffractive element 23. It will be seen, as will be explained hereinafter, that the presence of the interface layer 41 between the diffracting elements 21 and 23 makes it possible to increase the quantum efficiency of the photodetector with respect to the structure of Figures aA and 3B. More particularly, in the case of a silicon semiconductor substrate and of silicon oxide (forming the region of lower index of the diffractive element) and silicon (forming the highest index region) diffracting elements. of the diffracting element), an increase in the yield can be obtained when the layer 41 has a thickness of between 40 and 150 nia and an optical index greater than 2.5. This increase is particularly important when the layer 41 has a thickness between 50 and 80 nia and an optical index of the order of 3.6.
    [0013] By way of example, the layer 41 may be a polycrystalline silicon or amorphous silicon layer deposited on the upper surface of the diffractive element 21. As a variant, the materials of the diffractive element 21 are respectively silicon single-crystal and silicon oxide, the diffractive element 21 being buried under a monocrystalline silicon layer forming the layer 41. To form such a structure, it is possible to start from a first monocrystalline silicon substrate in which the Photoconversion Structure 1. The diffractive element 21 is formed on the side of the front face of a second monocrystalline silicon substrate. After the formation of the diffractive element 21, the second substrate is attached to the first substrate, so that the photoreceptive surface of the structure 1 is turned towards the diffractive element 21 (that is to say towards the front face second substrate). The second substrate can then be thinned by its rear face so as to keep above the diffractive element 21 only a thin thickness of monocrystalline silicon corresponding to the layer 41. The diffractive element can then be formed on the upper face of the layer 41.
    [0014] Figures aA and 5B are respectively a sectional view and a plan view schematically and partially showing another embodiment of a photodetector. This time we consider the case where the lateral dimensions of the semiconductor photoconversion structure of the photodetector are of the order of several times the operating wavelength of the photodetector, for example greater than twice the operating wavelength. which is for example between 300 and 3000 nia, and preferably between 600 and 3000 rua.
    [0015] By way of example, the photodetector of FIGS. 5A and 5B is a SPAD-type photodetector whose photoconversion semiconductor structure comprises, as in the example of FIG. 2, a photon-transforming layer 10 in electron pairs. holes of a first type of conductivity, for example N type, framed by two layers 12 and 13 of the opposite conductivity type. In the example of FIGS. 5A and 5B, the diffractive element 21 no longer comprises a single stud 21a (per photodetector) of index n1 laterally surrounded by a region 21b of index n2 different from ni, but one periodic array of studs 21a (by photodetector) of index n1 laterally separated by the region 21b of index n2 which forms a continuous layer substantially surmounting the entire photoreceptive surface with the exception of the portions surmounted by the pads 21a.
    [0016] Moreover, in the example of FIGS. 5A and 5B, the diffractive element 23 no longer comprises a single stud 23a of index n3 laterally surrounded by a region 23b of index n4 different from n3, but a network of pads. Period 23a of index n3 laterally separated by the region 23b of index n4 which forms a continuous layer substantially surmounting the entire photoreceptive surface with the exception of the portions surmounted by the pads 23a. The pads 21a, 23a and the regions 21b, 23b for separating the pads are of the same type as described in relation to FIGS. AA and 3B. In addition, as in the example of Figures aA and 3B, the pads 21a and 23a on the one hand and the regions 21b and 23b on the other hand diffracting elements 21 and 23 are substantially aligned vertically. By way of example, in each of the diffracting elements 21 and 23, the pitch of the pads may be equal to two-thirds, within 30% of the operating wavelength of the photodetector, the lateral dimensions of the pads may be between the tenth and half of the wavelength, and the distance between the pads may be of the order of one-sixth to two-thirds of the wavelength. The variant embodiment of FIG. 4 can be transposed to the embodiment of FIGS. 5A and 5B, namely that the diffracting elements 21 and 23 of FIG. 5A can be separated by an intermediate layer 41 of the type described in relation with FIG. 4. Comparative measurements have been made for a SPAD photodetector, in three distinct configurations B and C. In configuration A, the SPAD photodiode is coated with a single periodic array of pads, for example the grating 21 of the figure SA. In configuration B, the SPAD photodiode is coated with a stack of two periodic stud networks 21 and 23 superimposed, as shown in FIG. In configuration C, the SPAD photodiode is coated with a stack of two periodic stud networks 21 and 23 separated by a spacer layer 41 of the type described in relation to FIG. the pads 21a of the grating 21 are made of silicon oxide and are laterally separated by a continuous region 21b of monocrystalline silicon (that is, the grating 21 is formed in the upper part of the substrate 3036851 B14203 - DD15287JB - 13 -GR4-1144 15 semiconductor). The pads 23a of the grating 23 are made of polycrystalline silicon and are separated laterally by a continuous region 23b of silicon oxide. In configurations A and B, the layers 10 and 12 of the SPAD photodiode are silicon layers of about 1.5 and 0.7 μm in thickness respectively. The thickness of the network 21, that is to say the height of the pads 21a, is about 300 nia. The thickness of the grating 23, that is to say the height of the pads 23a, is about 180 nia.
    [0017] In configuration C, layers 10 and 12 of the SPAD photodiode are silicon layers of about 1.5 and 0.8 μm in thickness respectively. The networks 21 and 23 have substantially the same thickness, of the order of 240 nia. A parametric study was performed by varying, in each configuration, the width of the pads of the network or networks, and the inter-pads distance. In configuration A, it is found that a maximum absorption rate of 10.2% can be obtained, with a pad width of about 380 nia and an inter-pad distance of about 160 nm. In configuration B, it is found that the maximum absorption rate rises to 12.6%, for a pad width of about 250 nia and an inter-pad distance of about 280 nia. In the configuration C, a maximum absorption rate of 14.4% can be obtained, in the case where the intermediate layer 41 is a layer of silicon with a thickness of between 50 and 80 nia, for a width of dots. about 220 nia and an interplot distance of about 300 nia. It will be noted that in each of the aforementioned configurations, the absorption rates obtained also vary as a function of the thicknesses of the networks 21 and / or 23. However, it can be seen that whatever the thicknesses considered, the maximum quantum efficiency that can be achieved is always better with two superimposed networks (configuration B) than with a single network (configuration A), and is even better when the two networks are separated by intermediate layer 41 (FIG. 5). configuration C). Similar results are also observed when the types of networks are reversed, that is to say when the pads of the network 21 are in a high index material and are separated two by two by a low index material, and when the pads of the grating 23 are of a low index material and are separated two by two by a high index material. In a general manner, the skilled person will be able to optimize the dimensions of the studs by conventional simulation methods, by using simulation programs such as the DiffractMOD software (www.rsoftdesign.com) or the Grating Toolbox software (www. .lighttrans com). Thus, by means of this prior simulation calculation, the person skilled in the art can, without trial and error, dimension the diffracting elements 21 and 23 and, if appropriate, the intermediate layer 41 to increase the quantum yield or rate of photon absorption of a photodiode. Particular embodiments have been described. Various variations and modifications will be apparent to those skilled in the art. In particular, the materials constituting the diffracting elements 21 and 23 may be different from the aforementioned examples, provided that they are transparent to the operating wavelength and that they respect the relations previously described between the indices n1, n2, n3 and n4, namely that the differences n1-n2 and n3-n4 are non-zero and have opposite signs. In the embodiments described, to obtain a significant improvement in the quantum efficiency, the pads 21a, 23a are preferably sized taking into account not only the smallest wavelength X that the sensor is intended to capture, but also of the longest wavelength A that the sensor is intended to capture. In particular, the period (or not) of the pads 21a, respectively 23a is preferably less than X / ninc, where ninc is the optical index of the incident medium (the medium 35 located upstream of the diffracting elements 21 and 23), so that to avoid diffraction in the incident medium, and greater than Ainsc, nsc being the optical index of the semiconductor material of the structure 1, so as to have diffraction in the semiconductor medium 1.
    权利要求:
    Claims (10)
    [0001]
    REVENDICATIONS1. Photodetector comprising a photoelectric conversion structure of a semiconductor material, and on a photoreceptive surface of the conversion structure, a stack of first (21) and second (23) diffracting elements, the second element being above the first element, wherein: the first element (21) comprises at least one stud (21a) of a material of optical index n1 laterally surrounded by a region (21b) of a material of optical index n2 different from n1; the second element (23) comprises at least one stud (23a) of a material of optical index n3 laterally surrounded by a region (23b) of a material of optical index n4 different from n3; the studs (21a, 23a) of the first and second elements are substantially aligned vertically; and the differences in optical indices ni-n2 and n3-n4 are of opposite sign.
    [0002]
    2. Photodetector according to claim 1, wherein the pads (21a, 23a) of the first (21) and second (23) elements have substantially identical lateral dimensions and less than the operating wavelength of the photodetector. 20
    [0003]
    The photodetector according to claim 1 or 2, wherein the dimensions of the photoreceptive surface of the conversion structure are between 0.5 and 1.5 times the operating wavelength of the photodetector, and wherein each of the first (21) and second (23) elements comprises a single stud (21a, 23a) of the optical index material ni, respectively n3.
    [0004]
    The photodetector according to claim 1 or 2, wherein the dimensions of the photoreceptor surface of the conversion structure are greater than 2 times the operating wavelength of the photodetector, and wherein each of the first (21) and second (23) elements comprises a periodic array of pads (21a, 23a) in the optical index material ni, respectively n3. 3036851 B14203 - DD15287JB - 13-GR4-1144 19
    [0005]
    The photodetector according to any one of claims 1 to 4, wherein, in each of the first (21) and second (23) elements, said at least one pad (21a, 23a) and said region (21b, 23b) are in materials transparent to the operating wavelength of the photodetector.
    [0006]
    6. Photodetector according to any one of claims 1 to 5, further comprising an intermediate layer (41) of a material transparent to the operating wavelength of the photodetector, between the first (21) and second (23) 10 elements.
    [0007]
    7. Photodetector according to claim 6, wherein said intermediate layer (41) has a thickness of between 40 and 150 nm and has an optical index greater than 2.5.
    [0008]
    The photodetector according to any one of claims 1 to 7, wherein in at least one of the first (21) and second (23) elements, the region (21b, 23b) laterally surrounding said at least one The stud (21a, 23a) of the element is made of a conductive material and is connected to an application terminal of a bias potential.
    [0009]
    9. Photodetector according to any one of claims 1 to 8, in which the differences in optical indices ni-n2 and n3-n4 are, in absolute value, greater than or equal to 1 and preferably greater than or equal to 2. .
    [0010]
    10. Photodetector according to any one of claims 1 to 9, wherein in one of the first (21) and second (23) elements, said at least one pad (21a, 23a) and said region (21b , 23b) are respectively of silicon and silicon oxide, and in the other of the first (21) and second (23) elements, said at least one pad (21a, 23a) and said region (21b, 23b) are respectively in silicon oxide and silicon.
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    EP2801115B1|2017-02-15|Photodetection device
    EP3660930A1|2020-06-03|Method for manufacturing a photodiode array made of germanium and with low dark current
    FR3006105A1|2014-11-28|PHOTODIODE MATRIX WITH ADJUSTABLE LOAD ABSORPTION
    同族专利:
    公开号 | 公开日
    US9640704B2|2017-05-02|
    US20160351745A1|2016-12-01|
    EP3098858B1|2017-10-25|
    EP3098858A1|2016-11-30|
    FR3036851B1|2017-06-23|
    引用文献:
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    FR2964795A1|2010-09-09|2012-03-16|Commissariat Energie Atomique|PHOTODETECTEUR AND CORRESPONDING DETECTION MATRIX|
    FR3009889A1|2013-08-23|2015-02-27|Commissariat Energie Atomique|QUANTUM HIGH PERFORMANCE PHOTODIODE|
    FR2940522B1|2008-12-24|2011-03-18|Commissariat Energie Atomique|PHOTODETECTOR COMPRISING A VERY THIN SEMICONDUCTOR REGION|
    CN103081457B|2010-08-24|2016-04-13|富士胶片株式会社|Solid state image pickup device|US10340408B1|2018-05-17|2019-07-02|Hi Llc|Non-invasive wearable brain interface systems including a headgear and a plurality of self-contained photodetector units configured to removably attach to the headgear|
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    US10420498B1|2018-06-20|2019-09-24|Hi Llc|Spatial and temporal-based diffusive correlation spectroscopy systems and methods|
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    WO2020131148A1|2018-12-21|2020-06-25|Hi Llc|Biofeedback for awareness and modulation of mental state using a non-invasive brain interface system and method|
    US11081611B2|2019-05-21|2021-08-03|Hi Llc|Photodetector architectures for efficient fast-gating comprising a control system controlling a current drawn by an array of photodetectors with a single photon avalanche diode|
    US10868207B1|2019-06-06|2020-12-15|Hi Llc|Photodetector systems with low-power time-to-digital converter architectures to determine an arrival time of photon at a photodetector based on event detection time window|
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    法律状态:
    2016-05-24| PLFP| Fee payment|Year of fee payment: 2 |
    2016-12-02| PLSC| Search report ready|Effective date: 20161202 |
    2017-05-30| PLFP| Fee payment|Year of fee payment: 3 |
    2018-05-28| PLFP| Fee payment|Year of fee payment: 4 |
    2020-02-14| ST| Notification of lapse|Effective date: 20200108 |
    优先权:
    申请号 | 申请日 | 专利标题
    FR1554878A|FR3036851B1|2015-05-29|2015-05-29|QUANTUM HIGH PERFORMANCE PHOTODETECTOR|FR1554878A| FR3036851B1|2015-05-29|2015-05-29|QUANTUM HIGH PERFORMANCE PHOTODETECTOR|
    EP16170359.0A| EP3098858B1|2015-05-29|2016-05-19|Photodetector with high quantum efficiency|
    US15/163,550| US9640704B2|2015-05-29|2016-05-24|High quantum efficiency photodetector|
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