• 专利附录
  • 专利说明
  • 权利要求
  • 类似技术
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    • 专利摘要:
    Radiation and particle detection procedure using a semiconductor diode by modulating energy bands. The present invention describes a procedure that allows the detection of particles or radiation using a diode by modulating energy bands. The use of this invention is especially interesting for detecting incident radiation from charged particles or electromagnetic waves, so that the devices for detecting particles or radiation, which comprise at least one diode by modulating energy bands, are also an object of the invention. and the means necessary to carry out the detection. (Machine-translation by Google Translate, not legally binding)
    公开号:ES2770473A1
    申请号:ES201831304
    申请日:2018-12-30
    公开日:2020-07-01
    发明作者:Moral Carlos Navarro；Pérez Francisco Gámiz；González Carlos Márquez；Matarín Carlos Sampedro；Luca Donetti；Mora Santiago Navarro
    申请人:Universidad de Granada；
    IPC主号:
    专利说明:

    [0002] RADIATION AND PARTICULATE DETECTION PROCEDURE USING A
    [0004] TECHNICAL SECTOR
    [0006] The present invention can be categorized within the field of Physics, specifically in the area of Semiconductor Devices and more specifically in that of the use of semiconductors as measuring instruments.
    [0008] STATE OF THE ART
    [0009] Detection of particles or radiation
    [0010] The need to detect radiation sources is vital for certain areas and fields of daily use. The use of radiation detectors allows applications ranging from optical communications to the field of food and product packaging, passing through other areas such as their use in research in the Large Hadron Collider (LHC, English "large hadrnn collider ') in Geneva.
    [0012] Some detectors that have been widely used in the past (and still today) include multiplier tubes, scintillation crystals, GM ( “Geiger-Muller ') counters, and semiconductor-based detectors. Among the possible radiation detectors, the use of semiconductor materials as particle and radiation sensors is widely extended thanks to their greater efficiency. The first versions were known as crystal counters, but modern detectors are known as solid state detectors or detectors based on semiconductor diodes.
    [0014] In addition to higher efficiency, solid state detectors have other very advantageous qualities such as compact size, easy geometry configuration and higher speed. In return, semiconductor-based detectors are limited to small sizes and their functionality can be degraded by radiation-induced damage.
    [0016] Of the available semiconductor materials, silicon (Si) stands as dominant, mainly in diodes for spectroscopy of charged particles. Others Column IV semiconductors on the periodic table such as germanium (Ge) are used more to detect gamma rays. The use of more exotic materials, those formed by heterostructures of columns III-V and II-VI, is more restricted due to the inherent cost of the materials used.
    [0018] The usual mechanism in the detection of radiation sources in semiconductor devices, such as silicon, is the generation of charge in the form of electron-hole pairs (electrons that are excited from the valence band, where they generate a vacancy or hole , up to the conduction band) that modify the conductivity of the material. This is possible thanks to the absorption of energy that the radiation gives up when it hits the detector device. The detection of the current, called photocurrent, that this charge (electron-hole pairs) can generate is the principle of operation of devices such as: photodiodes pn (junction of semiconductor with acceptor-donor doped) or pin (junction of semiconductor with doped acceptor-intrinsic-donor), avalanche photodiodes or APD (from English “avalanche photo diodes '), photomultipliers and photoresistors or LDR (from English “ light-dependent resistor1'). All of them mainly based on the detection of electromagnetic radiation.
    [0020] As for the detection of charged particles, the principle is analogous. The incident particle gives up part of its energy as it passes through the semiconductor device, again generating charge in the form of electron-hole pairs that will also give rise to a current. Some existing semiconductor sensors include microstrip detectors or SSDs ( Silicon strip detectors) or position sensitive detectors (PSDs).
    [0022] Power band modulation diode
    [0023] The energy band modulation diode is a semiconductor device whose structure typically corresponds to a pin diode (doped silicon type acceptor / intrinsic / donor) manufactured in SOI (silicon-on-insulator) technology with two control terminals, one upper that does not completely cover the intrinsic zone and a lower one under the entire structure (Figure 1, above) [US20130069122A1]. Alternatively it can be implemented in an analogous way with a structure without upper control terminal and double lower control terminal (Figure 1, center) or in an extreme case with a pnpn diode without the need for control terminals. The latter case allows the use of conventional silicon technology in which the entire substrate is crystalline silicon, also known as technology bulk, saving the need to use SOI (Figure 1, below) but significantly limiting its usefulness since its sensitivity is not adjustable through polarization. Its implementation is preferably carried out in planar technology (Figure 1) although it is not obvious that it can be manufactured in three-dimensional structures such as FinFETs, tri-gate transistors or nanowires regardless of their shape or aspect ratio.
    [0024] This device can also be applied to protect devices against electrostatic discharge (ESD) [Y. Solaro et al., “Z2-FET: A promising FDSOI device for ESD protection”], as a dynamic memory cell DRAM [J. Wan et al., “A Compact Capacitor-Less High-Speed DRAM Using Field Effect-Controlled Charge Regeneration”] or as a surface charge sensor [A. Padilla, “Feedback FET: a novel transistor exhibiting steep switching behavior at low bias voltages”].
    [0026] However, the applicant is not aware of any document that describes or suggests the use of band modulation diodes to detect particles or electromagnetic radiation.
    [0028] OBJECT OF THE INVENTION
    [0030] The first object of the present invention is a method that allows the detection of particles or radiation using a diode by modulation of energy bands.
    [0032] The use of this invention is especially interesting for detecting incident radiation of charged particles or electromagnetic waves, therefore a second object of the invention is also a device, hereinafter "device of the invention", for the detection of particles or radiation, comprising at least one energy band modulation diode and the necessary means to carry out the detection. These devices can be, without excluding other possible devices, pn or pin photodiodes, avalanche photodiodes or APDs ( avalanche photo diodes ”), photomultipliers, microstrip or SSD sensors ( “ silicon strip detectors ”), sensors sensitive to the position or PSD (from the English “position sensitive detectors”), photoresistors or LDR (from the English “light-dependent resistor ').
    [0034] The use of the device object of the invention to detect particles or radiation has the following advantages in relation to the state of the art known to the applicant:
    [0035] • Negligible energy consumption in the pre-detection state.
    [0036] • Operation at room temperature without the need for refrigeration.
    [0037] • Compact design allowing high spatial resolution.
    [0038] • High value of the signal / noise ratio in the device, SNR (Signal to Noise Ratio). • High detection speed.
    [0039] • Low cost.
    [0040] • Compatibility with CMOS (Complementary Metal-Oxide-Semiconductor) manufacturing allowing easy co-integration with other circuits and elements for processing.
    [0041] • Easy adjustment of the sensitivity depending on the polarization and geometry of the device.
    [0043] BRIEF DESCRIPTION OF THE FIGURES
    [0045] Figure 1.- Schematic representation of the longitudinal section (anode-cathode direction) of three different structures of a diode by modulation of energy bands, where each number represents: 1 - Semiconductor substrate. 2 - Main Lower Control Terminal, BG, also referred to as GP ( Ground Plane). 3 - Silicon oxide / buried dielectric or BOX ( Buried OXide). 4 - Dielectric for lateral insulation. 5 - Cathode terminal, K. 6 - Device body. 7 - Silicon oxide / front dielectric to isolate top control contact. 8 - Upper control terminal that does not completely cover the body of the device, FG. 9 - Anode terminal, A. 10 - Secondary lower control terminal, BG2, also referred to as GP2. 11 - Device body with p-type acceptor doping. 12 - Body of the device with type n donor doping.
    [0047] Figure 2.- Schematic representation of a particle ( 13 ) or radiation ( 14 ) incident on the window ( 15 ) of the diode by modulation of energy bands.
    [0049] Figure 3.- Curve IV (intensity-voltage) characteristic of the diode by modulation of energy bands demonstrating the rapid transition between the regions of low conductivity ( 16 ) and that of high conductivity ( 17 ) that occurs at a voltage V on ( 18 ). The reverse transition occurs in V off ( 19 ). The range of voltages useful as a particle or radiation detector is comprised between V on and V off .
    [0051] Figure 4.- Typical polarization diagram of the diode by modulation of energy bands with the cathode terminal K as reference, V k . 20 - Polarization between control terminals upper FG and cathode K, V fg . 21 - Polarization between anode A terminals and cathode K, V a . 22 -Polarization between main lower control terminals BG and cathode K, V bg . 23 - Polarization between lower secondary control terminals BG2 and cathode K, V bg2 .
    [0053] Figure 5.- Longitudinal section (anode-cathode direction) of the electrostatic potential (equivalently energy), which shows how the modulation of the energy barriers in the body of the detector diode: when the barriers are large the conductivity is low and, at the collapse (V on ), the conductivity increases enormously abruptly. 24 - Anode region. 25 - Cathode region. 26 - Potential barrier induced by the polarization of the upper control FG ( V fg ), lower secondary control (V bg 2) or the doping of the region close to the anode itself. 27 - Potential barrier induced by the lower control polarization BG ( V bg ), or by the doping itself of the region close to the cathode. 28 - Collapse of the barrier caused by electrons diffused from the cathode. 29 - Collapse of the barrier caused by holes diffused from the anode.
    [0055] Figure 6.- Flow diagram for the calibration of the diode by modulation of energy bands.
    [0057] Figure 7.- Computer simulation of the behavior of the device before the impact of a particle ( 30 ) and its subsequent zeroing ( 31 ) for different anode polarizations. The polarization in the rest of the terminals is constant. 32 - V a <V off . 33 - V off <V a <V on . 34 -V a > V on . Only in 33 the detector is functional.
    [0059] Figure 8.- Charge density generated by a particle that impacts the area without the upper control terminal in the preferred configuration of the detector diode.
    [0061] Figure 9.- Curve I a -V a for the calibration of the diode by modulation of energy bands. V on = 1.035 V and V off = 0.740 V.
    [0063] Figure 10.- Temporal response of the diode by modulation of energy bands to the impact of a charged particle at t = 0.02 s and its subsequent zeroing at t = 0.10 s for different anode polarizations.
    [0065] Figure 11.- Diode currents by modulation of energy bands after the impact of a particle as a function of the LET parameter for various anode voltages.
    [0066] Figure 12.- Load generated under the upper control terminal, in the center of it, depending on the length of said terminal.
    [0068] EXPLANATION OF THE INVENTION
    [0069] Definitions
    [0070] The term "modulation of energy bands" comprises the mechanism by which a diode, under suitable polarization conditions, presents two clearly differentiated conduction states (conductivity) (with several orders of magnitude) in which the passage from one to another occurs abruptly thanks to a positive feedback mechanism. The low conductivity state is obtained when one or more energy barriers appear between the anode and cathode regions that limit the normal diffusion of carriers that occurs in a diode without energy band modulation. These barriers can be induced by additional control terminals, by changes in doping between anode and cathode, or by a combination of both causes. The positive feedback mechanism takes place as a consequence of the diffusion of carriers (holes from the anode and electrons from the cathode) that enter the body and reduce the barriers. At certain polarization conditions, the process becomes unstable and the diffusion of a carrier (hole for example) increases the diffusion of the other type of carrier (electron in this case) and vice versa, leading to a collapse in the barriers and an increase sudden in conductivity.
    [0072] The term "diode by modulation of energy bands" or, for simplicity in this description, "diode" refers to a device that comprises a junction of semiconductor materials of different type of doping and / or different band gap ( band gap, in English) and presents two very different conductivity operating zones, so that the transition between these operating zones occurs abruptly due to the modulation of energy bands. These devices can contain one or more spatial regions with different doping between their ends, provided that the device finally has two zones of operation with different conductivity.
    [0073] By way of a non-exclusive example, the term "diode" includes devices with pn type junctions (acceptor doping together with donor doping), pin (acceptor doping together with donor doping with an intrinsic region between the two) and pnpn (acceptor doping, donor, acceptor and donor).
    [0074] Throughout the description and the claims the word "comprise" and its variants are not intended to exclude other technical characteristics, additives, components or steps. For those skilled in the art, other objects, advantages and characteristics of the invention will emerge partly from the description and partly from the practice of the invention.
    [0076] Throughout this document, we will use a notation that uses the symbol “,” as the decimal separator.
    [0078] Procedure of the Invention
    [0079] In its first aspect, the present invention relates to a method, hereinafter "method of the invention", for detecting particles and radiation using a diode by modulation of energy bands.
    [0081] Specifically, the method of the invention comprises detecting a change in the conduction state of a diode by modulation of energy bands. This change in the conduction state is produced by the impact of a particle (13, Figure 2) in the region (hereinafter "window", 15 in Figure 2) that does not cover the upper control terminal (s) / es, either or by the exposure of said window to a source of electromagnetic radiation (14, Figure 2).
    [0083] The applicant has verified by computer-aided simulation that the interaction between a particle or radiation and the crystalline lattice of the diode by modulation of energy bands allows the generation of a charge (electron-hole pairs) capable of modifying the conduction state of the device and therefore both allowing to detect the impact or incidence of radiation.
    [0085] In a preferred embodiment, the method of the invention comprises a previous step of polarization of the diode, which allows modifying its sensitivity and discriminating the type of particle or radiation to be detected.
    [0087] Polarization stage
    [0088] Under suitable polarization conditions, an energy band modulation diode has unique electrical characteristics where the presence of two regions with very different conductivities stands out.
    [0089] On the one hand, the region of lower conductivity (16, Figure 3) is obtained as a consequence of the energy barriers present in the body of the device. Said energy barriers are induced with the upper control bias, FG, and lower, BG, (2 and 8 in Figure 1, above), with the bias of both lower control terminals, BG and BG2 (2 and 10 in Figure 1, center) or independently by the device body doping itself (11 and 12 in Figure 1, bottom).
    [0091] On the other hand, the region of highest conductivity (17, Figure 3) corresponds to the diode current when the energy barriers have collapsed. This collapse of the energy barriers occurs due to the presence of charge (electrons and / or holes in the intrinsic region). Since the switching between both regions occurs as a consequence of an unstable process of positive feedback, the change between regions is almost instantaneous (18 and 19, Figure 3).
    [0093] The criteria for selecting a determined polarization attend, in order, to the correct operation as a diode by modulation of energy bands, the detection sensitivity and finally the power consumption:
    [0094] 1) For proper sensing operation, the energy band modulation diode requires to be polarized in the low conductivity region (16, Figure 3). In a preferred embodiment, to achieve the barriers in the energy bands, the following will be fulfilled:
    [0095] a) The upper control voltage V fg (20, Figure 4, above) must be zero or positive while the lower control voltage V bg (22, Figure 4, above) must be zero or negative.
    [0096] b) The lower secondary control voltage Vbg2 (23, Figure 4, center) must be zero or positive while the lower control voltage V bg (22, Figure 4, center) must be zero or negative.
    [0097] c) Due to its absence, there is no polarization of the control terminals. The barriers are automatically induced thanks to the complementary doping of the body region (11 and 12, Figure 1, bottom).
    [0099] Other configurations (stress and doping) that give rise to the low conductivity state are also possible. The objective is to block the diffusion of carriers, holes from the anode (24, Figure 5) and electrons from the cathode (25, Figure 5), by means of energy barriers (26 and 27, Figure 5). This whole process depends on the own detector diode (geometry and architecture) as well as its distance and inclination to the radiation source.
    [0100] 2) The anode voltage V a (20, Figure 4) will be positive and always lower than the trigger voltage, V a <V on (18, Figure 3) and higher than the cut-off, V a > V off (19 , Figure 3). Where V on and V off depend on the materials in the device, its doping, geometry, temperature and, if they exist, the polarizations V fg , V bg and V bg 2 (20, 22 and 23 respectively in Figure 4) .
    [0101] 3) The charge generated by the incident particle or radiation will transiently shift V on (18, Figure 3) towards lower voltages (V on is reduced). Eventually, this shift will imply that VA> VON by switching the diode by modulation of energy bands towards the region of high conductivity (17, Figure 3 and 28/29, Figure 5) and detecting the incidence of the particle or radiation.
    [0102] 4) Given that a lower charge generated by the particle or radiation translates into a lower displacement of V on , in order to increase the sensitivity of the detector, V a will be polarized as close to V on as required without ever exceeding it . 5) Ultimately, it will be tried to use the lowest possible voltage in all the terminals fulfilling the previous conditions to save energy.
    [0104] The polarization adjustment also allows a possible correction for degradation due to time or previous impact of the detected particles. For this, the method of the invention comprises, in another preferred embodiment, a "zeroing" step.
    [0106] Stage of "reset" or zero setting
    [0107] In order to restart the detection conditions after the incidence of a particle or radiation, the detector has to recover its initial conditions by evacuating the excess charge. To do this, the diode polarization is changed so that the anode voltage V a (21, Figure 4) is less than V off , for example zero.
    [0109] To speed up the process, the upper and / or lower control voltages / is V fg , V bg and V bg 2 (20, 22 and 23 respectively in Figure 4) can also be set to zero simultaneously.
    [0111] Calibration stage
    [0112] As an initial stage prior to use as a detector of the diode by modulation of energy bands, a calibration stage is contemplated in which the voltages of each terminal will finally be adjusted. Said calibration process (outlined in Figure 6) is intended to Lastly, the DC ( direct current) characterization of the device of the invention to extract the useful voltage range of the device. For this, the current-voltage characteristic at the anode will be monitored, hereinafter I a -V a (Figure 3):
    [0113] 1) Depending on the final implementation, the voltages V fg , V bg and V bg 2 (20, 22 and 23 respectively in Figure 4) that correspond in each case must be initially defined, always complying with the polarization conditions before described.
    [0114] 2) The curve I a -V a will be extracted in an ascending direction (from 0 until exceeding the diode trip voltage) and descending (until the current returns to the low conductivity level), giving rise to the voltages V on and V off (18 and 19, Figure 3).
    [0115] 3) Knowing the characteristic voltages, the device of the invention is irradiated with the source of particles or radiation to be detected. It is important to adjust the dose and energy of the source to the minimum value to be detected as well as its distance and angle of emission. The energy band modulation diode will detect from that threshold.
    [0116] 4) Then an iterative process begins where V is increased gradually since V off (without exceeding V on) until the device of the invention switch. Two alternative cases are presented:
    [0117] a) The device switches for V off <V to <V on . The anode voltage to which it switches will be the one used and the calibration is complete.
    [0118] b) The diode does not switch satisfying V off <V a <V on . The diode, in its current configuration, does not allow the detection of said source of particles or radiation. You can vary the polarization of the device by returning to step 1 of the calibration. If there is no valid polarization, it is proposed to replace the diode with another with a different geometry with greater sensitivity.
    [0120] The possibility of the zeroing and calibration process being carried out manually or automatically is contemplated, in the latter case the object of the invention also comprising all the software and hardware elements necessary for said purpose.
    [0122] In case the diode does not have upper and lower control terminals (Figure 1, below), there is no calibration method and sensitivity adjustment is carried out during manufacture, modulating the diode's doping levels.
    [0123] The sensitivity of the diode depends on the polarization and its architecture and geometry. In general, it is true that sensitivity increases when:
    [0124] • Va tends to Von. The concentration of charge to lower the barriers is reduced making the device more sensitive.
    [0125] • The length of the upper control terminal (when present) is shortened. The generation before the incidence of a particle or radiation decays with distance. Reducing the length of the control terminal increases the possibilities of generating load under it to facilitate the collapse of the barriers.
    [0126] • The thickness of the area not covered by the upper control terminal is increased.
    [0128] In a preferred embodiment, the process of the invention comprises the following steps:
    [0129] - Calibration stage.
    [0130] - Detection stage, which in turn includes:
    [0131] 1) Zeroing.
    [0132] 2) Apply the polarization voltages obtained during the calibration. 3) Monitor the diode current by modulation of energy bands:
    [0133] a) If the current is low, there is no source of particles or radiation striking the device or its sensitivity is not low enough. b) If the current increases, a source of particles or radiation has been detected.
    [0135] Depending on the type and dose of radiation, defects may occur in the diode's crystal lattice, inducing degradation in detection. Therefore it is possible to have to perform the calibration after each detection stage or not.
    [0137] Device of the Invention
    [0138] The second object of the present invention is a device for the detection of particles and / or radiation, hereinafter "device of the invention" that comprises at least one diode for modulation of energy bands.
    [0140] Additionally, the device comprises means for detecting the current levels by means of amplifiers, comparators and their associated circuitry, as well as the same for powering the sensor.
    [0141] In a preferred embodiment, at least one diode, preferably all diodes included in the device of the invention is a planar diode.
    [0143] In another particular embodiment, the diode comprised in the device of the invention is made in three-dimensional technology such as FinFET, tri-gate transistor or nanowires of any size and aspect ratio.
    [0145] In the same way, although the diode structure will be manufactured using mainly silicon, it can be made in an equivalent way with other semiconductor materials such as elements of groups III-V or II-VI (homostructures and heterostructures) or other two-dimensional materials such as graphene. or TMDs (from English "transition metal dichalcogenide monolayers") or combination of the aforementioned.
    [0147] In a particular embodiment, the device of the invention comprises at least one polarized diode.
    [0149] As explained above, the diode is biased so that it is always functioning as a detector. As in this state, the diode has low conductivity, there is no current or it is very small, and therefore there is no power consumption or it is minimal. Once the charge is generated due to the impact of a particle or exposure to a radiation source, the device switches and presents a high current.
    [0151] The behavior of the device before the impact of a highly energetic particle depends on the polarization. It is observed how, taking into account the polarization of the anode (30, Figure 7), the impact of the particle allows the device to be switched. If the anode voltage (21, Figure 4) is lower than V off (19, Figure 3) or higher than V on (18, Figure 3), the device of the invention never reaches (32, Figure 7) or is always finds (34, Figure 7) in the high conductivity region (17, Figure 3), respectively, and does not function as a radiation detector. Only in the intermediate region can the device work by detecting the incidence of radiation by particles or electromagnetic waves (33, Figure 7). After detection, the initial state of the detector can be efficiently restored again with a zeroing operation (31, Figure 7) simply and quickly.
    [0153] The generation of charge is propagated throughout the device (Figure 8). Since the switching is mainly controlled by the load present in the body, by reducing its dimensions, both the sensitivity (more load) and its integration (smaller) are improved.
    [0154] In a preferred embodiment, the dimensions of the detector diode used in the device of the invention are between 10 microns and 50 nanometers in length. The width of the device is also highly configurable varying between settings with 50 nanometers up to 100 microns.
    [0156] In the same way, increasing the thickness of the silicon in the area not covered by the control terminal, it is possible to increase the energy that the particle gives up, generating more charge and therefore improving the sensitivity.
    [0158] Thus, in a preferred embodiment, the silicon in the area without the upper control terminal of the detector diode used in the device of the invention has a thickness between 5 and 100 nanometers. In the area covered by the upper control terminal, the thickness ranges from 5 to 20 nanometers. Other dimensions and geometries than those mentioned above are also possible.
    [0160] The angle of incidence of radiation on the surface of the detector can be used as sensitivity adjustment, so in another preferred embodiment, the device of the invention comprises the means (mechanisms and elements) necessary to be able to adjust said angle.
    [0162] On the other hand, the distance between the source and the detector can be used as sensitivity adjustment, so in another preferred embodiment, the device of the invention comprises the means (mechanisms and elements) necessary to be able to adjust said distance.
    [0163] The means used can allow to carry out these adjustments (angle and distance) manually or automatically and in person and remotely.
    [0165] In another preferred embodiment, the device comprises the terminals (metals and vias) necessary for an adequate application of the voltages necessary for polarization and its correct operation. In addition to this, the use of adjustable potentiometers can be contemplated so that their sensitivity can be adjusted with the polarization in situ. This allows the sensor to be adjusted to optimize the detection depending on the particle or radiation to be detected / discriminate the type of particle or radiation it detects.
    [0166] This polarization adjustment also allows a possible correction for degradation due to time or previous impact of the detected particles.
    [0167] In another particular embodiment, the device of the invention comprises a plurality of detector diodes with the same or different sensitivities.
    [0169] Different possibilities or a combination of them are contemplated:
    [0170] • Position detector: a matrix with identical detectors will allow, once calibrated and adjusted to the radiation source to be detected, to identify the place (s) of incidence.
    [0171] • Identification of the source: a matrix with detectors with different sensitivity, once calibrated to different doses or sources of radiation, allows to limit the energy, therefore the nature, of the particle / radiation based on which detectors switch or not.
    [0173] The physical implementation of the detector array caters for any two-dimensional or three-dimensional structure to optimize detection.
    [0175] Operation mode
    [0176] To carry out the procedure of the invention by means of the device of the invention, the following steps will be carried out:
    [0177] • Using one or more suitable devices, preferably stable voltage sources, whether they are cells or batteries to implement a portable detector or a power supply connected to the network, the calibration stage of the device described above will be carried out depending on the radiation to detect. The inclination, distance and polarization values will be known from this moment.
    [0178] • Once calibrated, the detector current will be monitored to discern possible changes towards a much higher current level, in which case the detection is positive and must be indicated by means of signals of any type (optical, acoustic or electrical among others. ).
    [0179] • Finally, the detector is zeroed to prepare for a new detection.
    [0181] This process can be extended to a multitude of sensors, in which case the calibration has to be carried out individually or together for one or different radiation sources with one or more intensities.
    [0182] MODES OF EMBODIMENT OF THE INVENTION
    [0184] To verify the feasibility of the invention (Figures 9-12), a diode by modulation of energy bands with a superior control terminal has been simulated with a computer. The total length is 400 nanometers (distributed equally between the area covered or not by the control terminal) and a width of 100 nanometers. The thicknesses are 22 nanometers in the part without upper control terminal and 7 nanometers in the rest. The doping profile corresponds to a p-i-n diode (the concentrations are, respectively, of (p) boron «1021 cm-3, (i) boron 1016 cm-3 and (n) arsenic« 1021 cm-3).
    [0186] The calibration begins by setting the voltages to induce the energy barriers and allow the low conduction state. We choose V fg = 1.2 V and V bg = -1 V with V k = 0 V. The curve I a -V a is then extracted to obtain the values V on and V off (Figure 9).
    [0188] Once the useful anode voltages (those between V on and V off ) are known, the behavior before the incidence of a charged particle is studied. Figure 10 illustrates the temporal response of the detector to the impact of a particle at t = 0.02 s and its subsequent zeroing at t = 0.1 s for different anode voltages (V a ). In this embodiment, the incident particle represents any set of one or more particles whose LET coefficient ( linear energy transfer '), defined as the amount of energy that the particle gives up per unit length dE / dx, in silicon is «13 keV / ^ m.
    [0190] It is observed how, after the impact, the current level is low if V a <V off (V a = 0.7 V) or does not change if V a > V on (V a = 1.1 V). Only when V off <V a <V on (V a = 0.8, 0.9 and 1.0 V) the device switches indicating the impact of a particle. Finally, it is appreciated how the setting to zero (at t = 0.1 s) allows the initial currents to be recovered. During the calibration process it would have increased to V gradually until it reaches switching.
    [0192] Figure 11 shows the anode current after particle impact for different LETs and anode voltages. It can be seen how the sensitivity increases (less LET is required) to switch as V a tends to V on . Figure 12 illustrates the dependence of the load generated under the upper control terminal as a function of the length of said terminal. By reducing the length, the charge generated by the particle in the area without a control terminal more effectively reaches the region under the contact, allowing the energy barriers to be lowered more easily.
    权利要求:
    Claims (14)
    [1]
    1. - Procedure for detecting particles and radiation that comprises detecting a change in the conduction state of a diode by modulation of energy bands.
    [2]
    2. - Procedure according to the previous claim, which comprises the prior polarization of the diode.
    [3]
    3. - Method according to any of the preceding claims, comprising a stage, after detection of a particle or radiation, in which the polarization of the diode is changed so that the anode voltage is zero.
    [4]
    4. - Procedure according to any of the preceding claims, comprising the following steps:
    - Calibration stage.
    - Detection stage, which in turn includes:
    - Change the polarization of the diode so that the anode voltage is lower than that of cut-off, preferably, cancel the upper and / or lower control voltages simultaneously.
    - Apply the polarization voltages obtained during the calibration. - Monitor the diode current by modulation of energy bands:
    o If the current is low, there is no source of particles or radiation striking the device or its sensitivity is not low enough.
    o If the current increases, a source of particles or radiation has been detected. After detection, the device is zeroed for a new detection.
    [5]
    5. - Device for the detection of particles and / or radiation, comprising at least one diode by modulating energy bands.
    [6]
    6. - Device according to the preceding claim characterized in that at least one diode is planar.
    [7]
    7. - Device according to claim 5 characterized in that at least one diode is made in three-dimensional technology.
    [8]
    8. - Device according to any of claims 5 to 7, characterized in that at least one diode is polarized.
    [9]
    9. - Device according to any of claims 5 to 8, characterized in that the dimensions of at least one diode are between 50 nanometers and 10 microns in length and between 50 nanometers and 100 microns in width.
    [10]
    10. - Device according to any of claims 5 to 9, characterized by the silicon in the area without a control terminal of at least one diode has a thickness between 5 and 100 nanometers. The thickness of the region under the upper control terminal ranges from 5 to 20 nanometers.
    [11]
    11. - Device according to any of claims 5 to 10, further comprising means for adjusting the angle of incidence of radiation on the surface of the detector that is not covered by an upper control terminal.
    [12]
    12. - Device according to any of claims 5 to 11, further comprising means to adjust the distance between the source and the detector.
    [13]
    13. - Device according to any of claims 5 to 12, further comprising adjustable potentiometers arranged so that its sensitivity can be adjusted with polarization.
    [14]
    14. - Device according to any of claims 5 to 13, comprising a plurality of diodes with different sensitivities.
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    同族专利:
    公开号 | 公开日
    WO2020141245A1|2020-07-09|
    ES2770473B2|2020-11-17|
    引用文献:
    公开号 | 申请日 | 公开日 | 申请人 | 专利标题
    EP0162942A1|1984-05-30|1985-12-04|Max-Planck-Gesellschaft zur Förderung der Wissenschaften e.V.|A semiconductor device for detecting electromagnetic radiation or particles|
    CN108807567A|2018-08-20|2018-11-13|中国科学院上海技术物理研究所|A kind of mercury cadmium telluride avalanche diode detector of modulated surface energy band|
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    ES201831304A|ES2770473B2|2018-12-30|2018-12-30|RADIATION AND PARTICLE DETECTION PROCEDURE USING A SEMICONDUCTOR DIODE BY MODULATION OF ENERGY BANDS|ES201831304A| ES2770473B2|2018-12-30|2018-12-30|RADIATION AND PARTICLE DETECTION PROCEDURE USING A SEMICONDUCTOR DIODE BY MODULATION OF ENERGY BANDS|
    PCT/ES2019/070897| WO2020141245A1|2018-12-30|2019-12-30|Method for detecting radiation and particles using a semiconductor diode based on energy band modulation|
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