EP3194991A1

EP3194991A1 - Hall effect magnetic sensor of the improved type and matrix comprising a plurality of said hall effect magnetic sensors.

Info

Publication number: EP3194991A1
Application number: EP15788186.3A
Authority: EP
Inventors: Daniele PERENZONI; Lucio Pancheri
Original assignee: Fondazione Bruno Kessler
Current assignee: Fondazione Bruno Kessler
Priority date: 2014-09-05
Filing date: 2015-09-04
Publication date: 2017-07-26
Also published as: WO2016035039A1

Abstract

The invention is a Hall effect magnetic sensor (1 ) suited to measure the intensity of a magnetic field (M), comprising a semiconductor substrate (2) subjected to doping on which the following elements are defined: two diodes arranged side by side; means (6) suited to inject minority charge carriers (100) and provided on the semiconductor substrate (2) along the axis of symmetry (X) defined between the two diodes (3), wherein the injector means (6) are configured to inject the minority charge carriers (100) in the semiconductor substrate (2) in such a way as to generate a diffusion current suited to flow under the two diodes (3); processing means (7) operatively connected to each output channel (32) of the two diodes (3) and configured to count the number of events induced by the minority charge carriers (100) on both of the diodes (3) during a pre-established time observation window (T) and to calculate the difference between the counts at the end of the observation time window (T). The Hall effect magnetic sensor (1 ) furthermore comprises a quenching circuit (5) connected in series to each one of the output channels (32) of the diodes (3) and the processing means (7) are operatively connected in an intermediate position between the output channels (32) and the quenching circuits (5).

Description

HALL EFFECT MAGNETIC SENSOR OF THE IMPROVED TYPE AND MATRIX COMPRISING A PLURALITY OF SAID HALL EFFECT MAGNETIC SENSORS.

DESCRIPTION

The invention concerns a Hall effect magnetic sensor of the improved type suited to measure the intensity of the magnetic field in which said sensor is immersed.

The invention concerns also a matrix comprising a plurality of said Hall effect magnetic sensors of the improved type positioned side by side.

Various methods for measuring a magnetic field are known, each one of which has its own characteristics and its own weaknesses. For this reason, the choice of the specific method to be employed to measure a magnetic field is made based on specific application needs.

The existence of various types of magnetic sensors is also known, each one of which implements one or more of said methods.

For example, there are sensors of the magnetoresistive type, comprising at least one conductor element with an electric resistance that is variable depending on the intensity of the magnetic field in which the conductor element is immersed.

Therefore, by measuring the value of said electric resistance it is possible to determine also the value of the intensity of said magnetic field.

However, disadvantageously, the cost and size of this type of sensors are not negligible.

Alternatively, in order to overcome the drawbacks described above, one of the most used methods for determining the intensity of a magnetic field consists of a measurement of the vectorial type that exploits the effect called "Hall effect" in technical jargon.

More precisely, said Hall effect can be defined as the determination of a difference in potential on the opposite sides of an electric conductor, due to a magnetic field that is perpendicular to the electric current flowing within the same conductor. In particular, the value of said difference in potential depends on the intensity of said magnetic field. Furthermore, the polarity of said difference in potential makes it possible to define also the direction of the same magnetic field.

Consequently, the magnetic sensors that exploit said Hall effect substantially comprise a conductor element, to the first two opposite ends of which a difference in potential is applied. Said difference in potential induces a current in the conductor element which, in the absence of a magnetic field, flows along the shortest rectilinear section joining said two first opposite ends. However, if these Hall effect magnetic sensors were immersed in a magnetic field having field lines perpendicular to the direction of said current, the latter would be subjected to a deflection orthogonal both to said rectilinear section and to the direction of the magnetic field lines. The direction of said deflection depends on the direction of the magnetic field lines to be measured.

Therefore, by measuring the difference in potential at the level of two second opposite ends of said conductor element, orthogonal to said rectilinear section of the current flow, it is possible to determine both the intensity and, as already said, the direction of the magnetic field in question.

It is also known that some types of these Hall effect magnetic sensors are made using the technology that in microelectronics is identified by the acronym "CMOS", obtaining the intrinsic advantages offered by this technology.

In particular, the CMOS Hall effect magnetic sensors comprise a semiconductor substrate A that in turn, as schematically represented in Figure 1 a illustrating the known art, includes a first layer A1 subjected to doping of a first type, p or n, above which a second layer A2 is defined, called "well" in technical jargon and subjected to doping of the opposite type, n or p, with respect to said first layer A1. Four metallic contacts B1 , B2, B3 and B4 arranged at the level of each end of a cross are defined on the second layer A2, as can be observed in Figure 1 b illustrating the known art.

As previously described, in order to measure a magnetic field using said type of CMOS Hall effect magnetic sensors, a difference in potential is applied to a first pair of metallic contacts opposite each other B1 and B2, in such a way as to induce a current flow between them, and the difference in potential generated due to the Hall effect when the sensor is immersed in a magnetic field is measured on the second pair of metallic contacts B3 and B4.

However, to disadvantage, said type of Hall effect magnetic sensors made with CMOS technology poses an important drawback. This drawback, in fact, is represented by the fact that among the various metallic contacts B1 , B2, B3 and B4 provided on the second layer A2 there are intrinsic resistive elements that determine the appearance of a thermal noise that is not negligible. In fact, to disadvantage, the presence of said thermal noise causes the increase of the minimum sensitivity threshold of the CMOS Hall effect magnetic sensors.

In other words, the CMOS magnetic sensors of the known art, disadvantageously, are not capable of detecting the presence of magnetic fields whose intensity is below said minimum threshold. For this reason, said CMOS magnetic sensors cannot be used for certain applications that, on the contrary, require that also low-intensity magnetic fields be detected, including also fields with intensity lower than said minimum threshold, for example in the field of real-time biological analysis, as described in greater detail below.

The present invention intends to overcome said drawbacks.

In particular, it is the object of the invention to provide a Hall effect magnetic sensor that is not subject to the appearance of said thermal noise or where, in the worst case, the value of said thermal noise is substantially negligible. Therefore, it is the object of the invention to provide a Hall effect magnetic sensor with a higher level of sensitivity compared to the magnetic sensors of the known art.

It is a further object of the invention to provide a Hall effect magnetic sensor whose production cost is lower than that of the magnetic sensors of the known art, even different from the Hall effect magnetic sensors, while at the same time guaranteeing the same performance levels.

It is not the least important object of the invention to provide a Hall effect magnetic sensor with reduced size, in such a way as to allow the definition of matrices with high resolution comprising a plurality of said type of magnetic sensors.

The objects illustrated above are achieved by the Hall effect magnetic sensor having the characteristics described in the main claim.

In particular, the Hall effect magnetic sensor that is the subject of the invention is characterized in that it comprises a properly doped semiconductor substrate on which two diodes are defined, which are arranged side by side and preferably but not necessarily are two diodes or more precisely photodiodes of the avalanche type operating in Geiger mode. Furthermore, the sensor of the invention comprises means for injecting minority charge carriers provided along the axis of symmetry defined between said two avalanche diodes. According to the invention, said injector means are configured to inject at least one minority charge carrier into said substrate of the sensor, in such a way as to generate a diffusion current suited to flow under the same avalanche diodes. Furthermore, the magnetic sensor of the invention comprises processing means that are operatively connected to each output channel of the two diodes and configured to count the number of avalanche events induced by said at least one minority charge carrier on both of the diodes, during a pre- established observation time window, and to calculate the difference between the counts at the end of said observation time window.

Regarding the avalanche diodes in Geiger mode, as is known they are fed above the threshold voltage by a quantity defined as "excess bias". When an electron-hole pair is generated, said avalanche diodes are accelerated by the high electric field until they generate another pair of carriers through impact ionization. A positive feedback is then produced, so that the current reaches very quickly its maximum value limited by the intrinsic resistance of the device and by the power supply voltage. In this mode, however, the current would remain constant and it would not be possible to detect other events after the first one, and the device would be unusable.

Thus, according to the invention, to enable the functionality of the Hall effect magnetic sensor of the invention again, a quenching circuit is introduced which is connected in series to each one of the output channels of the diodes. According to the invention, said processing means are operatively connected in an intermediate position between said output channels and the related quenching circuits.

Advantageously, reading each signal between the quenching circuit and the output channel of the diode means transducing the current signal generated by the diode into a voltage impulse whose amplitude equals the excess bias. In this way an impulse is obtained that can be processed both in the field of digital electronics, and thus without using an A/D conversion circuit, and in that of analog electronics. If the signal were collected under the quenching circuit, instead, the same signal should be read as a current value. To disadvantage, said reading as a current value would involve the need to have a very quick amplification circuit, with consequent high consumption of power and area, in addition to introducing a higher quantity of noise. Furthermore, it would also be necessary to carry out an A/D conversion of the signal in order to allow it to be read in the digital field. Therefore, the advantages of reading the signal between the output channel of the diode and the quenching circuit are substantially represented by the possibility to read the signal with a compact circuit in terms of surface area, low consumption and in a manner free of noise and electric cross-talk.

Furthermore, reading the signal between the output channel of the diode and the quenching circuit advantageously makes it possible to modify the voltage applied to the quenching circuit in order to quench the avalanche effect more effectively, and if necessary to pre-charge the diode in such a way as to prevent some types of noise, such as the so-called afterpulsing.

Further characteristics of the Hall effect magnetic sensor of the invention are described in the dependent claims.

The invention includes also the matrix comprising a plurality of Hall effect magnetic sensors carried out according to the invention, as described in claim 12.

Said objects, together with the advantages that are illustrated below, are highlighted in the description of a preferred embodiment of the invention that is provided by way of non-limiting example, with reference to the attached drawings, wherein:

- Figures 1 a and 1 b respectively show a side sectional view and a plan view of a Hall effect sensor made using the CMOS technology of the known art;

- Figure 2 shows a plan view of the magnetic sensor of the invention;

- Figure 3 shows a side sectional view of the magnetic sensor of the invention;

- Figure 4 schematically shows the flow of the diffusion current under the two diodes of the magnetic sensor of the invention in the absence of a magnetic field;

- Figure 5 schematically shows the flow of the diffusion current under the two diodes of the magnetic sensor of the invention in the presence of a magnetic field;

- Figure 6 shows a plan view of the matrix of magnetic sensors of the invention;

- Figure 7 shows a side sectional view of the matrix of magnetic sensors of the invention.

It should be noted that the following description, despite making reference to a particular embodiment of the Hall effect magnetic sensor of the invention made using the CMOS technology, is valid also for any other embodiment of the Hall effect magnetic sensor having the characteristics described in the first claim, even if it is made using construction techniques different from the CMOS technology.

The Hall effect magnetic sensor of the invention, hereinafter referred to simply as magnetic sensor for the sake of clarity, is shown in plan view in Figure 2 and in section view in Figure 3, and it is indicated as a whole by 1.

As already clearly indicated above, the magnetic sensor 1 of the invention makes it possible to measure the intensity of the magnetic field in which the same sensor 1 is immersed.

According to the invention, the magnetic sensor 1 comprises a semiconductor substrate 2 subjected to proper doping.

In particular, according to the preferred embodiment of the invention described herein, the semiconductor substrate 2 comprises a first layer 21 subjected to doping of a first type p, over which a second layer 22 is defined, which is subjected to doping of the opposite type, meaning n. This second layer 22, as is known, is defined as "n-well".

It cannot be excluded, however, that in a different alternative embodiment of the magnetic sensor 1 of the invention the doping processes to which the two layers 21 and 22 are subjected are inverted, in particular that the first layer 21 is subjected to doping of the n type and the second layer 22 is subjected to doping of the p type. Obviously, in this case, all the elements making up the magnetic sensor 1 of the invention and described below must present inverted doping processes with respect to those indicated or simply implied for the preferred embodiment of the invention which is being considered herein.

As can be observed in Figures 2 and 3, the magnetic sensor 1 of the invention comprises two diodes that, according to the preferred embodiment, are two diodes, or more precisely photodiodes, of the avalanche type operating in Geiger mode 3 (Geiger-mode APDs) provided on said second layer 22. The two avalanche diodes operating in Geiger mode 3, indicated here below - if not specified otherwise - simply as diodes 3, are arranged side by side, as can be seen in Figure 2, defining an axis of symmetry X between them. According to different embodiments of the invention, it cannot however be excluded that said diodes 3 are not of the avalanche type or that, even though of the avalanche type, they do not operate in Geiger mode, provided that, however, they can generate a signal in response to the detection of at least one minority charge carrier. Incidentally, as is known, an avalanche diode operating in Geiger mode is a diode comprising a p-n junction polarized inversely at a value exceeding the breakdown voltage. In this situation, until ideally there is at least one single charge carrier in the depletion region, no current flows in either of said diodes. When, on the contrary, at least one single charge carrier enters the depletion region, it is accelerated by the strong electric field present in the diode, consequently hitting the network of the latter. This impact causes the release of other charge carriers, which in turn hit the network and thus generate an avalanche effect. In other words, a rapid increase of the current that flows through the diode takes place, in a time in the order of nanoseconds or fractions of nanoseconds, until such current is limited in the manner described below through a proper quenching circuit. On arrival of said carrier, therefore, a current impulse in the order of milliamperes is generated, which can be easily detected by suitable processing means. Following the generation of said avalanche effect, there is a current flowing on the diode, which inhibits the capacity of the same diode to detect the arrival of a second charge carrier. In order to re-establish the initial conditions of the diode in such a way as to allow the same to detect a further charge carrier, it is necessary to carry to the diode terminals a voltage below the avalanche generation threshold and successively to apply again a voltage above said threshold. The time between the quenching of the diode and its recovery is called "dead time" in technical jargon.

Going back to the magnetic sensor 1 of the invention, according to the preferred embodiment of the invention itself the diodes 3 have substantially the same shape and size, as can be observed in Figure 2. Advantageously, said geometric identity determines a substantially identical behaviour of the two diodes 3 in the presence of the same external events generating the avalanche. In particular, preferably but not necessarily, both the diodes 3 have a substantially rectangular shape, with the long sides oriented towards a direction parallel to said axis of symmetry X.

Advantageously, said elongated shape in the direction parallel to the axis of symmetry X makes it possible to increase the sensitivity of the same sensor 1 , as is described in detail below.

It cannot be excluded, however, that in different embodiments of the invention the shape of the diodes 3 can be different from the rectangular shape, or that the same diodes 3 may not have said elongated shape.

According to the preferred embodiment of the invention, the sensitive surface 31 of each one of said diodes 3 oriented towards the outside is inhibited to the detection of photons through the superimposition of a light inhibitor filter 4. In particular, preferably, the light inhibitor filter 4 is made through a metallization layer 41 deposited on said sensitive surface 31 of each one of the diodes 3.

It cannot be excluded that in different embodiments of the invention said inhibitor filter 4 is carried out in a different manner than through deposition of a metallization layer 41 , for example through special polymers whose characteristics prevent the passage of light.

In any case, said inhibition is necessary, as it is important that in said diodes 3 used in the magnetic sensor 1 of the invention the possibility of occurrence of an avalanche effect due to the incidence of a photon on their sensitive surface 31 be avoided.

The magnetic sensor 1 of the invention furthermore comprises two quenching circuits 5, each one of which is connected in series to the output channel 32 of one of the two diodes 3. As mentioned above and as already known, said quenching circuits 5 have the function of stopping the avalanche effect that is generated on one of the two diodes 3 following an external event. In practice, said quenching circuits 5 serve to restore the initial conditions of said diodes 3 after the occurrence of an avalanche effect.

Preferably, each one of said two quenching circuits 5 comprises a quenching resistance 51.

It cannot be excluded, however, that in alternative embodiments of the sensor of the invention said quenching circuits 5 are of a type different from said quenching resistance 51 .

Furthermore, according to the preferred embodiment, the magnetic sensor 1 of the invention comprises injector means 6 suited to inject minority charge carriers 100 and provided on the same second layer 22 on which the diodes 3 are provided. In particular, said injector means 6 are defined along said axis of symmetry X of the two diodes 3. In greater detail, according to the preferred embodiment of the invention, the injector means 6 are provided on a point of incidence P between the axis of symmetry X and a second axis Y substantially orthogonal to the same axis of symmetry X. Said second orthogonal axis Y, as can be observed in Figure 2, is defined externally to the two diodes 3, meaning that it is not incident on the same two diodes 3.

It cannot be excluded, however, that in alternative embodiments of the invention the injector means 6 may be provided along said axis of symmetry X in an intermediate position between the two diodes 3.

From the operating point of view, the injector means 6 are configured to inject minority charge carriers 100 in the substrate 2, in particular in the second layer 22, so as to generate a diffusion current suited to flow under the two avalanche diodes 3.

For this reason, the special position of the injector means 6 with respect to the two diodes 3 makes it possible to optimize the performance of the magnetic sensor 1 of the invention, in particular to increase its sensitivity for the detection of magnetic fields even of low intensity. In greater detail, arranging the injector means 6 at the level of said axis of symmetry X advantageously makes it possible to define a diffusion current that, in the absence of a magnetic field, flows in a substantially balanced manner under both of the diodes 3. Furthermore, arranging the injector means 6 in a point P where they are not incident on the two diodes 3, as described in detail above, makes it possible to define a diffusion current that flows under the same diodes 3 along their entire length. This characteristic, as can be immediately understood, contributes to increasing the sensitivity of the entire magnetic sensor 1.

In fact, the purpose and the effect of the injection of said minority charge carriers 100 in the second layer 22, under the two diodes 3, consist in leading to an increase in the number of carriers in the multiplication region of the diodes, thus increasing the probability of generating an avalanche process. Preferably, according to the preferred embodiment of the invention, said injector means 6 comprise a diode 61 suited to be polarized in such a way as to inject the minority charge carriers 100 in the semiconductor substrate 2, in particular in the second layer 22. As can be observed in Figure 3, said diode 61 is obtained by subjecting a surface portion 22a of said second layer 22, at the level of the predefined point of incidence P, to doping of the p+ type. Finally, the magnetic sensor 1 of the invention comprises processing means 7 operatively connected to each output channel 32 of the two avalanche diodes 3 and configured to count the number of avalanche events induced by said minority charge carriers 100 on both of the avalanche diodes 3. In particular, said processing means 7 carry out said count simultaneously on both diodes 3 during a pre-established observation time window T. Furthermore, the same processing means 7 are configured to calculate, at the end of said observation time window T, the difference between the counts previously made. As schematically shown in Figure 2, in particular according to the preferred embodiment of the invention, preferably but not necessarily said processing means 7 are operatively connected in an intermediate position between said output channels 32 and the quenching circuits 5.

As already explained, said intermediate connection of the processing means 7 advantageously makes it possible to use as output signal from the diode the voltage impulse with amplitude equal to the excess bias that is generated in said intermediate point when the diode generates a current signal. In this way an impulse is obtained which can be processed both in the field of digital electronics, that is, without using an A/D conversion circuit, and in the field of analog electronics. Consequently, it is possible to read said voltage impulse with a compact circuit in terms of surface area, low consumption and in a manner free of noise and electric cross-talk.

It cannot be excluded, however, that in different embodiments of the invention the processing means 7 can be operatively connected to the end of the quenching circuit 5 opposite the end connected to one of the two output channels 32.

Advantageously, the fact that said processing means 7 calculate said difference makes it possible to filter any spurious count due to common disturbances that affect both the diodes 3.

In practice, when the magnetic sensor 1 of the invention is activated, that is, when the injector means 6 are polarized in a direct manner and the diodes 3 are polarized in such a way that they operate in Geiger mode, in the absence of a magnetic field, the minority charge carriers 100 injected in the second layer 22 and therefore the diffusion current are distributed in a balanced and symmetrical manner under said diodes 3, as schematically shown in Figure 4. Consequently, during a predefined observation time window T, said processing means 7 are expected to count the same number of avalanche events generated on both of the diodes 3. Said effects, as already explained, are generated by the flow of diffusion current under the same diodes 3. Therefore, according to expectations, the difference between the two counts calculated at the end of said observation time window T should be null.

On the contrary, when the magnetic sensor 1 of the invention is activated in the presence of a magnetic field M, in particular with its field lines perpendicular to the plane of development of the same sensor 1 , due to the Hall effect said minority charge carriers 100, and thus the diffusion current flowing under the diodes 3, are deflected towards one or the other of the two diodes 3, based on the direction of the magnetic field M.

Said deflection, schematically shown in Figure 5, determines an unbalance of the avalanche events that take place in the two diodes 3. In other words, the processing means 7, during said observation time window T, will count a different number of avalanche events that are started in the two diodes 3, exactly as a consequence of said deflection of the minority charges due to the Hall effect.

At the end of said observation time window T, the processing means 7 will define exactly the difference between the number of events generated during the observation period. The applicant has observed through experimental tests that said difference is linearly correlated to the intensity of the magnetic field M in which the magnetic field 1 of the invention is immersed. Furthermore, the sign of said difference makes it possible to establish also the direction of the magnetic field M, as described in detail above.

As already mentioned, the invention includes also the matrix 200 comprising a plurality of magnetic sensors positioned side by side, wherein each one of said magnetic sensors is a magnetic sensor 1 according to the invention. In particular, as can be observed in Figures 6 and 7, the two diodes 3 and the corresponding injector means 6 of each magnetic sensor 1 of the invention are defined on a common semiconductor substrate 2. In greater detail, as can be observed in Figure 7, said common substrate 2 comprises a first common layer 21 subjected to doping of the p type and for each one of said magnetic sensors 1 a second layer 22 is defined, which is subjected to doping of the n type and is electrically insulated from the second layers 22 of the other magnetic sensors 1.

Also in this case, however, it cannot be excluded that in an alternative embodiment of the matrix 200 of the invention the first layer 21 and the second layers 22 are subjected to inverted doping processes with respect to the preferred embodiment of the matrix 200 of the invention just described above and represented in Figures 6 and 7.

As previously mentioned, a matrix 200 of magnetic sensors 1 with high resolution due to the presence of a high number of magnetic sensors 1 on its surface and high sensitivity is suited to be used, for example, in the sector of real-time biological analysis.

In fact, as is known, according to the techniques used to identify the number of bacteria present in a biological material, each of them is associated with a magnetic-microbead. When excited, said microbeads generate a magnetic field whose intensity is proportional to their paramagnetic characteristic.

Therefore, by arranging the matrix 200 of magnetic sensors 1 of the invention in such a way that the field lines of the magnetic fields generated by said microbeads are perpendicular to the plane of development of the same matrix 200, it is possible to count accurately the number of bacteria present in the biological material and furthermore to locate the precise position of said bacteria in said material.

Based on the above, therefore, the Hall effect magnetic sensor and the matrix of Hall effect magnetic sensors of the invention achieve all the set objects. In particular, the invention achieves the object to provide a Hall effect magnetic sensor in which said thermal noise does not appear or at least has a substantially negligible value.

Therefore, the invention also achieves the object to provide a Hall effect magnetic sensor with higher sensitivity compared to the magnetic sensors of the known art.

The invention also achieves the further object to provide a Hall effect magnetic sensor that, while ensuring the same performance levels, has a lower production cost than the magnetic sensors of the known art, even different from those with Hall effect.

Finally, the invention also achieves the object to provide a Hall effect magnetic sensor with a small size, in such a way as to allow the definition of matrices with high resolution comprising a plurality of magnetic sensors of said type.

Claims

1 ) Hall effect magnetic sensor (1 ) suited to measure the intensity of the magnetic field (M) in which said sensor (1 ) is immersed, of the type comprising:

- a semiconductor substrate (2) subjected to doping, on which the following are defined:

- two diodes arranged side by side;

- injector means (6) suited to inject minority charge carriers (100) created on said semiconductor substrate (2) along the axis of symmetry (X) defined between said two diodes (3), said injector means (6) being configured in such a way as to inject said minority charge carriers (100) in said semiconductor substrate (2) so as to generate a diffusion current suited to flow under said two diodes (3);

- processing means (7) operatively connected to each output channel (32) of said two diodes (3) and configured so as to count the number of events induced by said minority charge carriers (100) on both of said diodes (3) during a predetermined observation time window (T) and to calculate the difference between said counts at the end of said observation time window (T);

characterized in that it comprises a quenching circuit (5) connected in series to each one of said output channels (32) of said diodes (3), said processing means (7) being operatively connected in an intermediate position between said output channels (32) and said quenching circuits (5).

2) Magnetic sensor (1 ) according to claim 1 , characterized in that said two diodes (3) are two avalanche diodes operating in Geiger mode (3).

3) Magnetic sensor (1 ) according to any of the preceding claims, characterized in that said semiconductor substrate (2) comprises a first layer (21 ) subjected to doping of a first type, p or n, over which there is a second layer (22) subjected to doping of the opposite type, n or p, with respect to said first layer, said two diodes (3) and said injector means (6) being obtained on said second layer (22).

4) Magnetic sensor (1 ) according to any of the preceding claims, characterized in that said diodes (3) and said injector means (6) are made with CMOS technology.

5) Magnetic sensor (1 ) according to any of the preceding claims, characterized in that said injector means (6) comprise a diode (61 ) suited to be polarized in such a way as to inject said minority charge carriers (100) in said semiconductor substrate (2).

6) Magnetic sensor (1 ) according to any of the preceding claims, characterized in that said diodes (3) have their sensitive surface (31 ) inhibited to the detection of photons through the superimposition of a light inhibitor filter (4).

7) Magnetic sensor (1 ) according to claim 6, characterized in that said inhibitor filter (4) comprises a metallization layer (41 ) deposited on the upper side of said sensitive surface (31 ) of said diodes (3).

8) Magnetic sensor (1 ) according to any of the preceding claims, characterized in that each one of said quenching circuits (5) comprises a quenching resistance (51 ).

9) Magnetic sensor (1 ) according to any of the preceding claims, characterized in that said two diodes (3) have substantially the same shape and size.

10) Magnetic sensor (1 ) according to claim 9, characterized in that each one of said two diodes (3) has a substantially rectangular shape with the long sides oriented according to a direction that is substantially parallel to said axis of symmetry (X).

1 1 ) Magnetic sensor (1 ) according to any of the preceding claims, characterized in that said injector means (6) are made on said semiconductor substrate (2) on a point of incidence (P) between said axis of symmetry (X) and a second axis (Y) substantially orthogonal to said axis of symmetry (X), said second orthogonal axis (Y) being defined outside said two diodes (3).

12) Matrix for magnetic sensors (200), of the type comprising a plurality of magnetic sensors positioned side by side, characterized in that each one of said magnetic sensors is of the type according to any of the preceding claims, wherein said two diodes (3) and said injector means (6) of each one of said magnetic sensors (1 ) are defined on a common semiconductor substrate (2) of said matrix (200).