Power device, system including the same, and method for manufacturing and controlling the same

Abstract

The present disclosure relates to power devices, systems including the same, and methods for manufacturing and controlling the same. Various embodiments of the present disclosure provide a power device comprising at least one first conductive element adapted to generate a magnetic field when a current flows through the element, and characterized in that the power device further comprises a Hall effect sensor electrically insulated from the first conductive element. The sensor and the first conductive element are arranged relative to each other so as to detect the magnetic field indicative of the current flowing through the first conductive element.

Description

Technical Field

[0001] The present disclosure relates to a power device, a system including a power device, a method for manufacturing a power device, and a method for controlling a power device. Background Art

[0002] As is known to all, a power device is an electronic device adapted to operate at high voltage and current (eg, a voltage of up to 1700 V during suppression and a current of up to tens / hundreds of amperes during conduction).

[0003] Specifically, semiconductor power devices are known, for example, based on silicon, gallium nitride (GaN), silicon carbide (SiC) or gallium arsenide (GaAs). For example, due to its high heat capacity, GaN can operate at temperatures up to about 400°C, has the possibility of maintaining high power (even hundreds of watts), and can operate at high frequencies (hundreds of megahertz). Therefore, GaN power devices can be used in multiple application fields. For example, they are commonly used as switching mode power supplies (SMPS), audio amplifiers, motor control, energy conversion devices, and devices used in the automotive field for hybrid and electric vehicles. Some examples of GaN power devices are power diodes, power transistors with finger electrode structures, thyristors, metal oxide semiconductor field effect transistors (MOSFETs) and super junction MOSFETs (SJ-MOS).

[0004] In particular, it is sometimes desirable to measure the current in a semiconductor power device, especially a semiconductor power device in which a corresponding driver circuit has been integrated. In fact, abnormal current absorption may cause the power device to heat up, which may cause the power device to be damaged.

[0005] Various solutions to the above-mentioned problem are known, in which an external measuring device (e.g., an ammeter) is coupled to the power device (or a system in which the power device is integrated). However, due to the burden and size of the external measuring device, this results in poor practicality and low usability of the power device.

[0006] Another solution consists in integrating one or more circuits dedicated to current measurement within a system comprising a power device. These circuits are based, for example, on current mirrors, which allow a portion of the current generated by the power device to be tapped in order to measure it and thereby obtain information about the operation of the device itself. This solution is not electrically insulating and therefore means that the portion of the generated current adapted for measurement cannot be operatively utilized by the device during operation, i.e. said portion of the current is subtracted from the output of the power device. In order to have an optimal measurement sensitivity, each current mirror should include a sensing resistor R sense , R sense The value is roughly equal to the on-state resistance R of the mirror itselfon The current dedicated to measurement is therefore non-negligible relative to the current generated by the GaN power device. Consequently, this solution degrades the performance of the GaN power device, thereby reducing its efficiency. Furthermore, it often involves complex circuitry, which increases the size and cost of the final product and increases the system's response time to conditions such as short circuits or overcurrent. Summary of the Invention

[0007] Various embodiments of the present disclosure provide a power device, a system including the power device, a method for manufacturing the power device, and a method for controlling the power device that will overcome the problems of the prior art. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] In order to better understand the present disclosure, various embodiments will now be described by way of non-limiting examples only, in which:

[0009] Figure 1 is a cross-sectional view of a power device according to one embodiment of the present disclosure;

[0010] Figure 1A An embodiment according to the present disclosure is shown Figure 1 A magnified detail of the power device;

[0011] Figure 2 A power device according to an embodiment of the present disclosure Figure 1A a schematic perspective view of a detail of;

[0012] Figure 3 According to one embodiment of the present disclosure Figure 1 The power devices along Figure 1 A cross-sectional view of a detail taken along section line II;

[0013] Figure 3A Schematically shows an embodiment of the present disclosure including Figure 1 A system of power devices;

[0014] Figures 4A-4D is a schematic cross-sectional view of details of a power device according to a corresponding embodiment of the present disclosure;

[0015] Figure 5A yes Figure 1 Cross-sectional views of different embodiments of power devices;

[0016] Figure 5B An embodiment according to the present disclosure is shown Figure 5A A magnified detail of the power device;

[0017] Figure 6 According to one embodiment of the present disclosure Figure 5A The power devices along Figure 5A A cross-sectional view of a detail taken along section line VV;

[0018] Figure 7 is Figure 1 a graphical representation of magnetic field measurements performed on a power device; and

[0019] Figure 8 The cross-sectional view shows Figure 1 and Figure 5A Different embodiments of the power device. DETAILED DESCRIPTION

[0020] In the subsequent description, common elements in different embodiments are denoted by the same reference numerals. So far, in the following, when GaN power devices are mentioned, this is only an example, as the proposed solution can also be applied to power devices implemented using other semiconductor materials (e.g., SiC and GaAs).

[0021] Figure 1 The power device 1 is shown in a Cartesian reference system of mutually orthogonal axes X, Y, Z. Specifically, Figure 1 The metallization layer of the power device 1 ( Figure 3 A cross-sectional view in a plane parallel to the plane XY defined by the axes X and Y of the power device 1 (along the plane XY) at the level of the second metallization layer MTL2 in FIG. Figure 3 (taken from the section line designated by III-III in the figure).

[0022] In the embodiment described by way of example, the power device 1 includes a high electron mobility field effect transistor (HEMT) 20 (hereinafter referred to as “transistor 20 ”) having a finger structure.

[0023] The power device 1 further comprises (eg in integrated form) a sensor 30 .

[0024] exist Figure 1 In FIG, the sensor 30 is represented with a dashed line, since it extends parallel to the metallization layer MTL2 , but at a height along Z that is different from the height at which the metallization layer MTL2 extends.

[0025] Therefore, the entire reference transistor 20 and sensor 30 will be referred to as a “power device 1 ” below.

[0026] refer to Figure 1 , transistor 20 is formed in a semiconductor body (in Figure 35 in the figure) or in the semiconductor body and includes a conductive source line 22 (hereinafter referred to as "source bus line 22") and a conductive drain line 24 (hereinafter referred to as "drain bus line 24"), which are separated from each other by an insulating region 23 (for example, silicon dioxide SiO2 or silicon nitride Si2N4 or some other dielectric material) to ensure their respective electrical insulation. Figure 1 In the embodiment of FIG. 1 , the source bus line 22 has a surface 22 a (parallel to a plane YZ defined by axes Y and Z), the surface 22 a facing a first surface 23 a (parallel to plane YZ) of the insulating region 23, and the drain bus line 24 has a surface 24 a parallel to plane YZ and facing a second surface 23 b (parallel to plane YZ) of the insulating region 23. The insulating region 23 thus extends along axis X between the source bus line 22 and the drain bus line 24. Furthermore, the source bus line 22 is electrically connected to a source pad (not shown), which is adapted to be set at a source voltage V in use. source At, and the drain bus 24 is electrically connected to a drain pad (not shown), which is adapted to be set at a drain voltage V in use. drain Place.

[0027] A plurality of source fingers 26 extend through the insulating region 23 and are electrically connected to the source bus line 22. Figure 1 In FIG, three source fingers 26 are shown, but the number may vary, as will be apparent to one skilled in the art. Figure 1 In the embodiment shown by way of example in the cross-sectional view of , the source fingers 26 have a rectangular shape and are identical to one another, their main extension being parallel to the axis X. In particular, each source finger 26 has: a first secondary side 26 a parallel to the axis Y (i.e., extending along the width of the rectangular shape) and adjacent to the surface 22 a of the source bus 22; a second secondary side 26 b parallel to the axis Y (i.e., extending along the width of the rectangular shape) and to the first secondary side 26 a (opposite the first secondary side 26 a with respect to the source finger 26 under consideration) and facing the drain bus 24; a first main side 26 c parallel to the axis X (i.e., extending along the length of the rectangular shape) and perpendicular to the secondary sides 26 a, 26 b; and a second main side 26 d parallel to the axis X (i.e., extending along the length of the rectangular shape) and to the first main side 26 c, perpendicular to the secondary sides 26 a, 26 b and opposite the first main side 26 c with respect to the source finger under consideration. Each source finger 26 is electrically connected to the source bus 22 at the first secondary side 26 a , while the insulating region 23 electrically insulates each source finger 26 at the second secondary side 26 b and the primary sides 26 c , 26 d .

[0028] Likewise, a plurality of drain fingers 28 extend through the insulating region 23 and are electrically connected to the drain bus line 24 . Figure 1Two drain fingers 28 are shown, but the number itself varies in a manner obvious to a person skilled in the art. Figure 1 In the embodiment shown by way of example in the cross-sectional view of , the drain fingers 28 have a rectangular shape and are identical to one another, their main extension being parallel to the axis X. In particular, each drain finger 28 has: a first secondary side 28 a parallel to the axis Y (i.e., extending along the width of the rectangular shape) and adjacent to the surface 24 a of the drain bus 24; a second secondary side 28 b parallel to the axis Y (i.e., extending along the width of the rectangular shape) and the first secondary side 28 a (opposite the first secondary side 28 a with respect to the drain finger 28 under consideration) and facing the source bus 22; a first main side 28 c parallel to the axis X (i.e., extending along the length of the rectangular shape) and perpendicular to the secondary sides 28 a, 28 b; and a second main side 28 d parallel to the axis X (i.e., extending along the length of the rectangular shape) and the first main side 28 c, perpendicular to the secondary sides 28 a, 28 b and opposite the first main side 28 c with respect to the drain finger 28 under consideration. Each drain finger 28 is electrically connected to the drain bus 24 and another drain finger 28 at a first secondary side 28 a , while the insulating region 23 electrically insulates each drain finger 28 at a second secondary side 28 b and primary sides 28 c , 28 d .

[0029] The source fingers 26 and drain fingers 28 have a staggered structure. In other words, each source finger 26 extends at least partially between two drain fingers 28, and each drain finger 28 extends at least partially between two source fingers 26. Specifically, each source finger 26 has a first main side 26 c that at least partially faces the second main side 28 d of the corresponding drain finger 28, and a second main side 26 d that at least partially faces the first main side 28 c of the corresponding other drain finger 28. Similarly, each drain finger 28 has a first main side 28 c that at least partially faces the second main side 26 d of the corresponding source finger 26, and a second main side 28 d that at least partially faces the first main side 26 c of the corresponding other source finger 26. Thus, the insulating region 23 electrically insulates each source finger 26 (respectively, drain finger 28 ) from the two drain fingers 28 (respectively, source fingers 26 ) adjacent to and facing it.

[0030] More generally, each source finger 26 is at least partially adjacent to the drain finger 28, and each drain finger 28 is at least partially adjacent to the source finger 26. In detail, the distance between the secondary side 26 b of the source finger 26 and the second surface 23 b of the insulating region 23 (specifically, along the axis X) may be equal to the distance between the secondary side 28 b of the drain finger 28 and the first surface 23 a of the insulating region 23 (specifically, along the axis X). Furthermore, the distance between the second main side 26 d of each source finger 26 and the first main side 28 c of the drain finger 28 facing it (specifically, along the axis Y) may be equal to the distance between the first main side 26 c of each source finger 26 and the second main side 28 d of the drain finger 28 facing it (specifically, along the axis Y). Furthermore, the fingers 26, 28 facing each other and close to each other are positioned so that the second main side 26d of the source finger 26 and the first main side 28c of the drain finger 28 facing it (respectively, the first main side 26c of the source finger 26 and the second main side 28d of the drain finger 28 facing it) face each other over at least 80% of their extension.

[0031] As is well known, the current flowing through each source finger 26 is higher at the source bus line 22 and decreases as it moves away from the source bus line 22 toward the drain bus line 24 along the axis X. In other words, a current density gradient exists in each source finger 26, with the current flowing through the source finger 26 decreasing from the first secondary side 26 a to the second secondary side 26 b. Similarly, the current flowing through each drain finger 28 is higher at the drain bus line 24 and decreases as it moves away from the drain bus line 24 toward the source bus line 22 along the axis X. In other words, a current density gradient exists in each drain finger 28, with the current flowing through the drain finger 28 decreasing from the first secondary side 28 a to the second secondary side 28 b.

[0032] refer to Figure 1 and Figure 1A , the sensor 30 is a Hall effect magnetic sensor. Specifically, the Hall effect is expected to be present in the presence of both a current orthogonal to the current and a Hall potential V H Orthogonal measurement magnetic field ( Figure 2 B in s ) in the case of current ( Figure 2 I in a , and the Hall potential V H A potential difference (called the "Hall potential") is established between two different points in a conductive material through which currents flow (orthogonal). Figure 2 V H express).

[0033] Since a conductor through which current flows generates a magnetic field, each finger 26, 28 contributes to the generation of a corresponding magnetic field B. In detail, considering the ideal case of a fixed current I flowing through an infinite straight wire (thus of infinitesimal cross-section) in a vacuum, it can be seen that, according to the Biot-Savart law, the magnetic field B(r) at a point P in space can be calculated as:

[0034]

[0035] Where r is the minimum distance between point P and the wire ( is the unit vector of r), is the unit vector of the fixed current I, and μ0 is the permeability of the vacuum. This expression can be extended, in a manner known per se to those skilled in the art, to the case of media with a dielectric constant different from that of vacuum, as well as to the case of conductors with non-negligible cross-sections (e.g., fingers 26, 28 of transistor 20). Specifically, a conductor with a non-negligible cross-section (e.g., one of fingers 26, 28, considering the ideal case of infinite main extension) can be considered as a "continuum" of infinitesimal conductors, each of which is traversed by an infinitesimal current equal to the current density in the finger 26, 28 in question. Thus, by integrating the field calculated by applying the Biot-Savart law to each conductor, the contribution of each infinitesimal conductor to the magnetic field can be obtained. Since it neither takes into account the finite main dimensions of fingers 26, 28 and the resulting influence on the field geometry, nor the variable current density along the extension of the finger itself, as described, the result is clearly approximate. Nevertheless, the applicant has found that this result represents a reliable and computationally fast estimate of the magnetic field B in all cases. In a manner known per se to a person skilled in the art, the exact spatial distribution of the magnetic field B is obtained via simulations (for example, three-dimensional simulations based on the finite element method).

[0036] By associating the sensor 30 with the transistor 20, it is possible to measure the magnetic field B generated by the fingers 26, 28 in the vicinity of the sensor 30 and thus calculate the current flowing therethrough. In this way, the operation of the monitoring transistor 20 can be monitored by measuring the current flowing through each finger 26, 28 without drawing a portion of said current (i.e., by making an electrically isolated measurement) and therefore without reducing the efficiency of the transistor 20.

[0037] In detail, Figure 2 One embodiment of a sensor 30 is schematically shown, which is based on a conductive structure shaped like a cross, more specifically a cross with vertical arms of equal length, also called a "Greek cross". Figure 2 The sensor 30 is parallel to the plane XY, in particular parallel to Figure 1 The plane of the cross section shown ( Figure 3 The cross-sectional line II-II) in FIG.

[0038] The sensor 30 comprises a conductive region 3 formed on or in a semiconductor body 5. According to one embodiment, the conductive region 3 extends in a plane XY defined by axes X and Y and has four arms 7, 8, 9, 10. In the embodiment described by way of example, the conductive region 3 comprises a stack 14 of semiconductor materials adapted to form a two-dimensional electron gas (2DEG) region ( Figure 3 ). In particular, as described below, the stack of semiconductor materials comprises one or more heterostructures. As will be better described below, the conductive region 3 is laterally insulated from the rest of the semiconductor body 5 by an insulating layer 16.

[0039] According to one embodiment, the first arm 7 of the conductive area 3 is electrically connected to a power supply V a , while the second arm 8 in continuation of the first arm 7 is electrically connected to a reference potential (e.g. equal to 0 V). The third arm 9 and the fourth arm 10 in continuation of each other are arranged orthogonal to the first arm 7 and the second arm 8. Figure 2 In FIG, first arm 7 and second arm 8 extend parallel to axis X, and third arm 9 and fourth arm 10 extend parallel to axis Y. Furthermore, arms 7-10 meet in a central region 12, which is the center (or centroid) of the cross formed thereby. Arm 7 has an end opposite central region 12 (hereinafter referred to as first outer end 7a) relative to the extension of arm 7; arm 8 has an end opposite central region 12 (hereinafter referred to as second outer end 8a) relative to the extension of arm 8. Arm 9 has an end opposite central region 12 (hereinafter referred to as third outer end 9a) relative to the extension of arm 9. Arm 10 has an end opposite central region 12 (hereinafter referred to as fourth outer end 10a) relative to the extension of arm 10.

[0040] In the embodiment described by way of example, the Hall potential V H The supply current I is measured electrically between the mutually opposing ends of the third arm 9 and the fourth arm 10 (ie, between the third outer end 9a and the fourth outer end 10a). a From the first arm 7 to the second arm 8 along the axis X, and in the presence of the measured magnetic field B s (as better described, corresponding to the component of the magnetic field B generated by at least one of the fingers 26, 28) in the case of a Hall potential V generated along the axis Y due to the Lorentz force H .

[0041] In fact, the charge carriers (electrons in this embodiment) conducting in the conducting region 3 are subject to a Lorentz force of the vector form according to the following expression Impact:

[0042]

[0043] where q is the charge of the electron, is the electron drift velocity vector (i.e., the velocity vector of the supply current I a applied electron velocity), and Is the indication of measuring magnetic field B s Due to the Lorentz force, the supply current I a and measure the magnetic field B s A non-zero component is generated in the direction Y along the trajectory of the electron, and thus a potential difference (ie, the Hall potential V H ).

[0044] A sensor 30 is disposed adjacent at least one of the fingers 26 , 28 .

[0045] according to Figure 1 In this embodiment, the third arm 9 of the sensor 30 faces one of the drain fingers 28. In top view, in plane XY, the drain finger 28 and the sensor 30 are laterally staggered; that is, the drain finger 28 is not arranged vertically above the sensor 30 (along the Z axis). Specifically, the third outer end 9a faces the second main side 28d of the drain finger 28 in question, and the third arm 9 has a main extension perpendicular to the second main side 28d. The first arm 7 and the second arm 8 of the sensor 30 have a main extension along the axis X, parallel to the second main side 28d. Furthermore, the fourth outer end 10a, opposite the third outer end 9a along the axis Y, does not face any source finger 26 of the transistor 20 (specifically, there is no source finger 26 whose first main side 26c faces the second main side 28d of the drain finger 28 in question and, therefore, faces the fourth outer end 10a). The central region 12 of the sensor 30 is closer to at least one of the first main side 28c and the second main side 28d of the drain finger 28 under consideration than to each of the first main side 28c and the second main side 28d of the remaining drain fingers 28. In detail, the sensor 30 is arranged so that a first minimum path or distance exists between the central region 12 and at least one of the first main side 28c and the second main side 28d of the drain finger 28 under consideration. The above-mentioned first minimum path is shorter than any other path between the central region 12 of the sensor 30 and each of the first main side 28c and the second main side 28d of the remaining drain fingers 28. Figure 1, the drain finger 28 under consideration is also denoted by reference numeral 28'. Furthermore, the central region 12 of the sensor 30 is closer to the first secondary side 28a of the drain finger 28 under consideration than to the second secondary side 28b of the drain finger 28 under consideration, so as to measure the current flowing through the drain finger 28 at a higher current. Specifically, the second minimum path between the central region 12 and the first secondary side 28a of the drain finger 28 under consideration is shorter than the third minimum path between the central region 12 and the second secondary side 28b of the drain finger 28 under consideration.

[0046] According to various embodiments, the third arm 9 of the sensor 30 faces one of the source fingers 26. In top view, in plane XY, the source finger 26 and the sensor 30 are laterally staggered, i.e., the source finger 26 is not arranged vertically above the sensor 30 (along the Z axis). Specifically, the third outer end 9a faces the second main side 26d of the source finger 26 in question, and the third arm 9 has a main extension perpendicular to this second main side 26d; the first arm 7 and the second arm 8 of the sensor 30 have a main extension along axis X, parallel to this second main side 26d. Furthermore, the fourth outer end 10a, opposite the third outer end 9a along axis Y, does not face any drain finger 28 of the transistor 20 (specifically, there is no drain finger 28 whose first main side 28c faces the second main side 26d of the source finger 26 in question, and therefore faces the fourth outer end 10a). In detail, sensor 30 is arranged such that a fourth minimum path exists between central region 12 and at least one of the first and second main sides 26 c, 26 d of the source finger 26 in question. The aforementioned fourth minimum path is shorter than any other path between central region 12 of sensor 30 and each of the first and second main sides 26 c, 26 d of the remaining source fingers 26.

[0047] According to yet another embodiment, sensor 30 extends between one of source fingers 26 and one of drain fingers 28. Specifically, outer end 7a, 8a, 9a, 10a of one of arms 7, 8, 9, 10 faces first main side 26c of source finger 26 (respectively, second main side 26d of source finger 26), and outer end 7a, 8a, 9a, 10a of arms 7, 8, 9, 10 opposite to central region 12 faces second main side 28d of drain finger 28 (respectively, first main side 28c of drain finger 28). Specifically, a fifth minimum distance between central region 12 and first main side 26c of source finger 26 (respectively, second main side 26d of source finger 26) is different from a sixth minimum distance between central region 12 and second main side 28d of drain finger 28 (respectively, first main side 28c of drain finger 28). Typically, the position of the sensor 30 between the source finger 26 and the drain finger 28 is chosen in a manner known per se to a person skilled in the art in order to prevent the magnetic field B from vanishing or being excessively weakened in the vicinity of the sensor 30 due to the superposition of the contributions of the fingers 26, 28 under consideration. For example, the third outer end 9 a faces the second main side 28 d of the drain finger 28, while the fourth outer end 10 a faces the first main side 28 c of the drain finger 28.

[0048] Figure 3 It is along the section line II( Figure 1 ) is a cross-sectional view taken along a plane parallel to plane YZ. Specifically, Figure 3 The cross-sectional view at least partially shows sensor 30 and one of drain fingers 28. Even if the subsequent description is made with reference to one of drain fingers 28, it is equally applicable to reference to one of source fingers 26 and / or the simultaneous presence of one of drain fingers 28 and one of source fingers 26. Furthermore, since they are known per se, the present description and drawings omit the gate pad, gate fingers, and connections to one or more gate terminals of transistor 20.

[0049] Specifically, through Figure 1The power device 1 described in the example of FIG. 1 comprises a semiconductor body 5 comprising a semiconductor substrate 42 (e.g., silicon having a 111-type crystal orientation) and a stack 14, which is formed, for example, epitaxially on the semiconductor substrate 42. According to one embodiment, the stack 14 comprises a gallium nitride (GaN) layer 44 and an aluminum gallium nitride (AlGaN) layer 46. The GaN layer 44 is interposed between the semiconductor layer 42 and the AlGaN layer 46 along the axis Z; moreover, the AlGaN layer 46 has a surface opposite the GaN layer 44 with respect to the AlGaN layer 46 (hereinafter, the top surface 46a, corresponding to the section line II-II). The GaN layer 44 contacts the AlGaN layer 46 to form a heterostructure, which is adapted to generate a 2DEG layer in a manner known per se (which extends near the interface between the GaN layer 44 and the AlGaN layer 46 and in particular at the interface between the GaN layer 44 and the AlGaN layer 46). The GaN layer 44 may have a thickness in a direction parallel to the axis Z ranging from about 300 nm to 1.5 μm, while the AlGaN layer 46 (eg, AlGaN) may have a thickness in a direction parallel to the axis Z ranging from about 300 nm to 1.5 μm. 0.3 Ga 0.7 N) may have a thickness in a range of about 10 nm to 40 nm in a direction parallel to the Z-axis. Note that in other implementations (not shown), additional layers may be present between the semiconductor substrate 42 and the AlGaN layer 46 in a manner known per se to those skilled in the art.

[0050] A portion of the AlGaN layer 46 (corresponding to the conductive region 3) is electrically insulated from the rest of the AlGaN layer 46 by an insulating layer 16 (a dielectric or insulating material (e.g., SiO2 or Si2N4)). In fact, the insulating layer 16 completely surrounds the periphery of the conductive region 3 (e.g., Figure 2) and extends in stack 14 so as to electrically insulate the 2DEG present in conductive region 3 from the 2DEG present outside conductive region 3 (i.e., the 2DEG that participates in the conduction of transistor 20 during use), thereby electrically insulating sensor 30 with respect to transistor 20. Insulating layer 16 thus defines the form of sensor 30 (in the embodiment described by way of example, a ballistic device). Specifically, insulating layer 16 extends in stack 14 and has: a width in a direction parallel to axis Y ranging from approximately 200 nm to 2 μm; and a thickness in a direction parallel to axis Z, which, starting from top surface 46 a of AlGaN layer 46, is equal to approximately 100 nm to 300 nm, thereby interrupting the 2DEG layer. The thickness of insulating layer 16 is therefore greater than the thickness of AlGaN layer 46, and insulating layer 16 also extends at least partially in GaN layer 44. Therefore, the conductive region 3 is laterally insulated from the semiconductor body 5, where "laterally insulated" means that, even though a leakage current (e.g., less than 1% of the conduction current) may exist between the conductive region 3 and the semiconductor body 5 (specifically, the rest of the 2DEG layer, not included in the conductive region 3), the conductive region 3 does not participate in the conduction of the transistor 20. Specifically, this is because the conduction current flows in the 2DEG and the insulating layer 16 electrically insulates the 2DEG present in the conductive region 3 from the 2DEG present outside the conductive region 3, thereby electrically isolating the conductive region 3 of the sensor 30 from the transistor 20.

[0051] A first terminal 47a and a second terminal 47b (conductive material, such as a metal (e.g., tungsten W, aluminum Al, or copper Cu) or even polysilicon) extend on the top surface 46a of the AlGaN layer 46 and are provided at a portion of the conductive region 3 adapted to function as the third arm 9 and a portion of the conductive region 3 adapted to function as the fourth arm 10, respectively. The first terminal 47a and the second terminal 47b are in electrical contact with the third arm 9 and the fourth arm 10, respectively. According to one embodiment, the first terminal 47a and the second terminal 47b are adapted to acquire the Hall potential V generated during use of the sensor 30. H .

[0052] also, Figure 3A drain terminal 49 is shown, extending above the top surface 46 a of the AlGaN layer 46 in the region of the stack 14 adapted to function as the drain region of the transistor 20. In use, conduction of the transistor 20 occurs via a conduction current flowing in the 2DEG between a source region (similar to the drain region and electrically connected to one of the source fingers 26) and a drain region (electrically connected to one of the drain fingers 28), and the conduction of the transistor 20 is controlled in a manner known per se via a gate terminal (arranged on the top surface 46 a of the AlGaN layer 46 so as to control the conduction of the transistor 20). In a manner known per se, the source bus 22 and the drain bus 24 may also be connected to the 2DEG layer by doping or by creating a conductive connection of a metallic type. Note that transistor 20 typically includes multiple source regions (and corresponding multiple source terminals, each of which is electrically connected to a corresponding source finger 26) and multiple drain regions (and corresponding multiple drain terminals 49, each of which is electrically connected to a corresponding drain finger 28) extending parallel to axis X.

[0053] In addition, Figure 3 , the first metallization layer MTL1 and the second metallization layer MTL2 extend over the stack 14. Specifically, the first metallization layer MTL1 extends between the stack 14 and the second metallization layer MTL2. The first metallization layer MTL1 and the second metallization layer MTL2 are conductive materials such as metals (e.g., aluminum or copper) and are buried in and electrically insulated from each other by the insulating region 23. The insulating region 23 can therefore be formed by one or more dielectric material layers alternating with the metallization layers MTL1 and MTL2. Specifically, the insulating region 23 extends over and contacts the top surface 46a of the AlGaN layer 46 and extends over the insulating layer 16. Figure 3 The illustrated first metallization layer MTL1 includes a first portion 50a, a second portion 50b, and a third portion 50c that are not in direct electrical contact with each other.

[0054] The first portion 50a is electrically connected to the first terminal 47a (and therefore to the third arm 9) via a first contact (via) 48a (conductive material, such as metal (e.g., Al or Cu)) extending through the insulating region 23. The second portion 50b is electrically connected to the second terminal 47b (and therefore to the fourth arm 10) via a second contact 48b (conductive material, such as metal (e.g., Al or Cu)) extending through the insulating region 23. The third portion 50c is electrically connected to the drain terminal 49 via one or more third contacts 48c (conductive material, such as tungsten or polysilicon) extending through the insulating region 23 and having a main extension parallel to the axis X. In the embodiment described by way of example and during use of the power device 1, the first portion 50a and the second portion 50b are adapted to acquire the Hall voltage V of the sensor 30. H , and the third portion 50c is adapted to provide an appropriate bias to the drain region. Similarly, the other portions of the first metallization layer MTL1 (at Figure 1 The first and second arms 7 and 8 are electrically connected to the source regions to provide them with appropriate bias, and are electrically connected to the first and second arms 7 and 8 for biasing the sensor 30 (in detail, for delivering the supply current I a ).

[0055] Figure 3 The second metallization layer MTL2 shown has a main extension parallel to the axis X and has a thickness greater than the thickness of the first metallization layer MTL1 . Figure 1 The cross-sectional view corresponds to the second metallization layer MTL2 (ie, at a height corresponding to the second metallization layer MTL2, along Figure 3 The cross-section line III-III is shown cut off). The fingers 26, 28 and the bus bars 22, 24 therefore belong to the second metallization layer MTL2. Figure 3 The drain finger 28 under consideration is at least partially shown. The drain finger 28 is electrically connected to the third portion 50c of the first metallization layer MTL1 via one or more fourth contacts 52 (of a conductive material, such as a metal (e.g., W, Al, or Cu)) extending through the insulating region 23. During use of the power device 1, the drain finger 28 is thus adapted to distribute current toward the third portion 50c of the first metallization layer MTL1, which is then provided to the drain terminal 49 for biasing the drain region. However, it should be noted that the power device 1 may include further metallization and / or interconnect layers (e.g., further contacts) in a manner known per se to a person skilled in the art.

[0056] Figure 3AA system 68 is shown comprising a power device 1 and a control unit 70. The power device 1 and the control unit 70 are electrically connected in a manner known per se via one or more electrical connections 72. The control unit 70 is configured to provide a number of operational functions, including managing the bias of the transistor 20, managing the bias of the sensor 30 (i.e. applying the supply current Ia) to obtain its Hall potential V H The acquired data are processed (post-processed) in order to obtain the current flowing through the finger 26, 28 in question. To this end, the control unit 70 (which may be integrated in the same die 74 as the power device 1) comprises a processing unit 76 of a type known per se for processing the data (e.g. a microcontroller or microprocessor), a drive circuit 78 for driving the sensor 30 and / or the transistor 20, and possibly a power supply circuit 80. According to one embodiment, the control unit 70 also comprises an output connection configured to connect it to an external device, for example adapted to read and display on a screen the measurements made by the sensor 30.

[0057] Reference Pass Figure 4A The operation of the power device 1 is described in detail below based on the embodiment represented by the example in FIG.

[0058] Specifically, as previously discussed, during use of the power device 1, the drain fingers 28 are configured to have a current flowing through them. The current passing through the drain fingers 28 generates a corresponding magnetic field B in a known manner (e.g., according to the Biot-Savart law). In detail, since the widths of the fingers 26, 28 in a direction parallel to the axis Y are much smaller than their corresponding lengths in a direction parallel to the axis X (e.g., their widths in a direction parallel to the axis Y are less than 10% of their corresponding lengths in a direction parallel to the axis X), the generated magnetic field B has lines of the magnetic field B that are concentric with each other and have a substantially elliptical or circular shape in a plane parallel to the plane YZ ( Figure 4A In particular, assuming that the lines 60 of the magnetic field B are elliptical, all the lines 60 of the magnetic field B are centered at a point (hereinafter referred to as the center of the ellipse 62). According to one embodiment, this point coincides with the centroid of the drain finger 28 in a cross section parallel to the plane YZ (cross-section line II). In a manner known per se, the lines 60 of the magnetic field B that are farther from the center of the ellipse 62 have a greater perimeter and a smaller intensity of the magnetic field B (in a direction tangential to the above-mentioned lines 60) than the lines 60 of the magnetic field B that are closer to the center of the ellipse 62.

[0059] The sensor 30 is adapted to measure the measurement magnetic field B flowing through the conductive area 3. s (Specifically, the magnetic field B is measured at the center area 12 sSince the sensor 30 has a planar structure, it is adapted to measure only a component of the magnetic field that is perpendicular to the plane in which the sensor 30 is located (here parallel to the plane XY and corresponding to the top surface 46a of the AlGaN layer 46). In other words, when the magnetic field B is perpendicular to the plane in which the sensor 30 is located (i.e., when the magnetic field B extends along the axis Z), Figure 2 The measured magnetic field B s coincides with the magnetic field B, and when the magnetic field B does not have normal incidence in the plane where the sensor 30 is located, Figure 2 The measured magnetic field B s = is equal to the projection of the magnetic field B along the axis Z. According to one embodiment, via the expression B s = Bcos(α), to calculate the measured magnetic field B in scalar form s , where α is the tilt angle formed between the intersection line 64 (connecting the center of the ellipse 62 and the center of the central region 12, and the center belongs to the intersection line) and the top surface 46a of the AlGaN layer 46. According to one embodiment, the tilt angle α ranges between 0° (excluding the value) and 90°.

[0060] The control unit 70 is thus configured to obtain the measured Hall potential V from the sensor 30. H ; From the Hall potential V H Initially, according to techniques known per se (e.g., by means of the Hall potential V H With the measured magnetic field B s The linear relationship between the two) is used to calculate the measured magnetic field B s ; and from the measured magnetic field B s Begin by calculating the magnetic field B (according to one embodiment, by applying the expression B=B s / cos(α)). The value of the magnetic field B thus obtained is then associated via the control unit 70 with the corresponding current value of the drain finger 28 (e.g. via a look-up table provided intentionally). For example, during a suitable measurement and / or electrical testing process, a precise and selected current value is supplied to the power device 1 at the input and the measured magnetic field B acquired by the sensor 30 is read at the output. s and then write it into a look-up table in a manner known per se.

[0061] Since the magnetic field B s is a function of the strength of the magnetic field B and the tilt angle α, so as the position between the drain finger 28 and the sensor 30 changes, the sensitivity of detecting the current in the drain finger 28 changes. In the following, another embodiment of the power device 1 is described, which shows the measurement of the magnetic field B. s the impact of this dependence.

[0062] Specifically, Figure 5ADifferent embodiments of a power device 1 are shown (hereby indicated by reference numeral 101), wherein a sensor 30 (preferably in Figure 5B Shown in) About Figure 1 The sensor shown in is displaced along the Y axis.

[0063] according to Figure 5A In the embodiment of the present invention, in the view in the plane XY, the drain finger 28 (also indicated by the reference numeral 28 ″) and the sensor 30 under consideration are not laterally staggered, and the drain finger 28 under consideration is at least partially arranged vertically above the sensor 30 (along the axis Z). In other words, the drain finger 28 and the sensor 30 at least partially overlap each other. During the design of the power device 1, the precompensation of possible current pinch-off phenomena in the drain region is known and will not be described in detail. In particular, in Figure 5A , the drain finger 28 is arranged vertically above at least a portion of the third arm 9 (along the axis Z). In detail, in this embodiment, the seventh minimum path ratio between the central area 12 and the second main side 28d of the drain finger 28 (i.e., the drain finger 28″) closer to the sensor 30 is Figure 1 The first minimum path of the embodiment is shorter.

[0064] In addition, Figure 6 1 and 2. The power device 101 is shown in a cross-sectional view (section line VV) along the plane XY. Specifically, the second main side 28d of the drain finger 28 corresponds vertically (along the Z axis) to the sensor 30; that is, in a top view in the plane XY, it is arranged between the central area 12 and the third outer end 9a of the sensor 30.

[0065] like Figure 4B As shown, the intersection line 64 of the power device 101 is smaller than the intersection line 64 of the power device 1. Since the distance between the center of the ellipse 62 and the top surface 46a of the AlGaN layer 46 is the same in both the power device 1 and the power device 101 (given that it depends on the thickness of the metallization layers MTL1 and MTL2 and the insulating region 23, which is considered to be constant), the tilt angle α is larger in the case of the power device 101 than in the case of the power device 1 (that is, the value of cos(α) is smaller), and the intensity of the magnetic field B is higher.

[0066] Figure 4CA different embodiment of a power device 1 is shown (herein designated by reference numeral 201), in which the sensor 30 does not extend parallel to the XY plane, but rather extends in a trench 204. Specifically, the semiconductor substrate 42 of the power device 201 includes a trench 204, which is obtained, for example, by anisotropic etching, followed by the growth of the stack 14 and the formation of the sensor 30, a process known per se and therefore not described in detail herein. For example, in the case where the semiconductor substrate 42 is silicon with a 100 crystal orientation, the trench 204 is obtained by etching with potassium hydroxide (KOH). The trench 204 can have the shape of a pyramid or a frustum of a pyramid (here with a square base, the sides of the square base being comprised between 150 μm and 300 μm), and has at least one first sloping wall 204 a and one second sloping wall 204 b opposite the first sloping wall 204 a in the trench 204. In the case described by way of example, the first slanted wall 204a and the second slanted wall 204b both have a crystal orientation 111, extend in a direction transverse to the axes Y and Z and form a trench angle β ( Figure 4C and 4D ), the trench angle β has a magnitude that depends on the manufacturing process and the particular semiconductor material used. In the present embodiment, given the frustum-shaped trench 204 with a square bottom, and considering the semiconductor substrate 42 as silicon with a crystal orientation of 100, the trench angle β is equal to 54.7°.

[0067] exist Figure 4C In FIG. 2 , the sensor 30 extends along the first inclined wall 204 a , thereby enabling measurement of the magnetic field B and thus of the current in the drain finger 28 .

[0068] Figure 4D Another embodiment of the power device 1 is shown (hence designated here by reference numeral 301) in which the sensor 30 extends along the second inclined wall 204b. In this case, the sensor 30 is adapted to measure higher values ​​of the magnetic field B, given the smaller intersection line 64 and the smaller inclination angle α, and to measure the magnetic field B given the smaller inclination angle α. s The value of is close to the value of the magnetic field B, thus ensuring high sensitivity of the measurement of the sensor 30.

[0069] exist Figure 4C In the case and Figure 4D, the sensor 30 is arranged such that there is an eighth minimum path between the central region 12 and at least one of the first main side 28 c and the second main side 28 d of the drain finger 28 under consideration. The eighth minimum path is shorter than any other path between the central region 12 of the sensor 30 and each of the first and second main sides 26 c, 26 d, 28 c, 28 d of the remaining fingers 26, 28.

[0070] Even though it has been described Figure 4C and Figure 4D Embodiments of the present invention also contemplate the case where the groove 204 has a shape different from that indicated (e.g., a groove with a triangular or hexagonal base, three or six side walls), and / or where the sensor 30 extends not only along one of the slanted walls, but also on more than one of the slanted walls of the groove 204 (e.g., on the slanted walls 204a, 204b and on the bottom wall of the groove 204), even if the central area 12 belongs to and is located on one of the slanted walls. Furthermore, the case where the groove 204 is replaced by a protrusion in a manner known per se is also contemplated, as well as the case where the slanted walls do not extend in a direction transverse to the axes Y and Z (e.g., they extend in a direction transverse to the axes X and Z and are inclined with respect to a plane parallel to the plane XY).

[0071] According to one embodiment (particularly one embodiment relating to the power device 1), Figure 7 shows the measured magnetic field B as the distance between the sensor 30 and the drain finger 28 varies. s Specifically, the measured magnetic field B is obtained by simulation in a manner known per se. s , considering that: the thickness of drain finger 28 (along the Z axis) is approximately 3 μm; the secondary sides 28 a, 28 b of drain finger 28 are approximately 9 μm; the current flowing through drain finger 28 is approximately 70 mA (under this specification, when the current exceeds this value, the possibility of damage to drain finger 28 due to electromigration phenomena is not negligible); and the distance between the center of ellipse 62 and the top surface 46 a of AlGaN layer 46 is approximately 4.5 μm. Measuring magnetic field B s is expressed as a function of the distance taken along the axis Y (in detail, in top view parallel to the plane XY) between the second main side 28d of the drain finger 28 under consideration and the central area 12 of the sensor 30. Figure 7 In the graph of FIG, the origin of the abscissa axis corresponds to the second main side 28d of the drain finger 28, and the positive value of the abscissa corresponds to the position moving from the second main side 28d toward the sensor 30 along the axis Y. In detail, the magnetic field B is measured. s There is an increasing trend along the abscissa axis starting from the origin of the axis, and then there is a decreasing trend.

[0072] The presence of the two trends and, therefore, the presence of a maximum of the magnetic field measured at a certain distance of the sensor 30 from the drain finger 28 (i.e., at a certain offset between the sensor 30 and the drain finger 28) is a result of the distribution of the magnetic field B, which impinges on the top surface 46a of the AlGaN layer 46 with an inclination increasingly close to the normal, but with a decreasing absolute value, as the distance from the drain finger 28 that generates the magnetic field B increases. Therefore, the problem of the correct positioning of the sensor 30 with respect to the drain finger 28 can be solved by optimizing the two conflicting objectives (i.e., the inclination angle α and the strength of the magnetic field B), resulting in a measured magnetic field B that is consistent with the sensor 30 being able to detect. s The peak value corresponds to the compromise.

[0073] In fact, in Figure 7 In the example of FIG. 1 , the magnetic field B is measured at a value Y* of the distance between the second main side 28 d and the central region 12 . s The value Y* is the distance between the second main side 28d and the central area 12 (measurement magnetic field B s The distance between the second main side 28d and the central area 12 (measurement magnetic field B s In this embodiment, the value Y* is about 1.5 μm, and the corresponding measured magnetic field B s This value Y* therefore makes it possible to optimize the sensitivity of the sensor 30 .

[0074] From what has been described above, the advantages of the present disclosure are obvious.

[0075] In particular, the power devices 1, 101, 201, 301 exhibit small dimensions and can be integrated in a die, and the sensor 30, being based on the Hall effect, ensures high measurement sensitivity of the magnetic field B. In particular, at least in the case of a 2DEG ballistic implementation, the sensor 30 enables measurement of magnetic fields of the order of magnitude of the Earth's magnetic field (typically in the range of 20 μT to 70 μT).

[0076] The sensor 30 is adapted to measure a magnetic field B that is electrically isolated from the current flowing through the transistor 20 , thus making it possible to calculate the current flowing in the fingers 26 , 28 without reducing the efficiency and performance of the transistor 20 .

[0077] Power devices 1, 101, 201, 301 do not require complex circuitry to operate, thereby reducing manufacturing complexity and increasing practicality of use. Furthermore, power devices 1, 101, 201, 301 enable the provision of a closed-loop control system that monitors the amount of current flowing through fingers 26, 28. Consequently, a rapid response to conditions such as short circuits and / or overcurrent conditions in transistor 20 can be achieved, thereby preventing damage to transistor 20 or other components operatively coupled to sensor 30.

[0078] Furthermore, positioning the sensor 30 near the first secondary sides 26 a, 28 a of the fingers 26, 28 enables measurements to be made in an area where the current flowing through the fingers 26, 28 is maximum and the field effects caused by the close fingers 26, 28 (specifically, the superposition of several magnetic fields B generated by different fingers 26, 28 that are close to each other and close to the sensor 30) are minimized.

[0079] Furthermore, the fact that there is no connection between the sensor 30 and the transistor 20 simplifies the overall layout of the system compared to the case of a measurement circuit in which the sensor 30 and the transistor 20 are electrically connected together.

[0080] Finally, it is obvious that modifications and variations can be made to what has been described and illustrated herein without departing from the scope of the present disclosure.

[0081] Specifically, according to another embodiment, sensor 30 extends between two drain fingers 28 (alternatively, between two source fingers 26). Specifically, consider the case provided by the example of a first drain finger 28 and a second drain finger 28 (adjacent to each other and continuous in a series of drain fingers 28), wherein the second main side 28 d of the first drain finger 28 and the first main side 28 c of the second drain finger 28 at least partially face the same source finger 26 (respectively, the first main side 26 c and the second main side 26 d of the aforementioned source finger 26). For example, in a top view parallel to plane XY, first outer end 7 a faces second secondary side 26 b of source finger 26, second outer end 8 a faces second surface 23 b of insulating region 23, third outer end 9 a faces second main side 28 d of first drain finger 28, and fourth outer end 10 a faces first main side 28 c of second drain finger 28.

[0082] Furthermore, according to another embodiment, a plurality of sensors 30 may be provided in the power device (e.g., in positions corresponding to the drain finger 28 under consideration) (alternatively, the source finger 26 under consideration). Specifically, in the view of the plane XY, a first sensor 30a and a second sensor 30b (similar to the sensor 30 and therefore not described again) are arranged facing and opposite each other in a direction parallel to the axis Y with respect to the drain finger 28 under consideration, so as to enable differential measurement of the drain finger 28 under consideration. -shaped member 28". In more detail, the first sensor 30a faces the first main side 28c (alternatively, the first main side 26c) of the drain finger 28" and the second sensor 30b faces the second main side 28d (alternatively, the second main side 26d) of the drain finger 28", thereby realizing a differential type of measurement. The first sensor 30a and the second sensor 30b are identical to each other and are symmetrical in top view (i.e. parallel to the plane XY) about the drain finger 28" (alternatively, the source finger 26) under consideration. The first sensor 30a and the second sensor 30b are therefore arranged to measure the same line 60 of the magnetic field B and, in detail, the magnetic fields B in the respective central areas 12 have directions opposite to each other. Therefore, according to a technique known per se, the common mode of the measurements of the first sensor 30a and the second sensor 30b can be eliminated, thereby improving the signal-to-noise ratio (SNR) of the overall measurement.

[0083] According to yet another embodiment, the accuracy of detecting the current flowing in the drain finger 28″ under consideration (and similarly in the source finger 26) is improved by utilizing a further plurality of sensors 30 (e.g., a third sensor 30c and a fourth sensor 30d) operatively coupled to the same transistor 20. The third sensor 30c and the fourth sensor 30d are similar to the previously described sensor 30, and in particular, the fourth sensor 30d comprises a respective conductive region 3 in the shape of a cross having a central region 12. The third sensor 30c is arranged in the power device so as to measure the magnetic field B generated by the drain finger 28″ (in particular, according to one of the arrangements of sensors 30 previously discussed with reference to the power devices 1, 101, 201, 301), and the fourth sensor 30d is arranged so as to measure the electromagnetic interference around the aforementioned drain finger 28″ (in particular, the drain finger 28″ is arranged vertically above the central region 12 of the fourth sensor 30d along the axis Z). In fact, by arranging the drain finger 28″ so as to also be located vertically above the central area 12 of the fourth sensor 30d (in the view of the plane XY), the measured magnetic field Bs acquired via the fourth sensor 30d is primarily indicative of all the magnetic fields B generated by the fingers 26, 28 close to the drain finger 28″ (taking into account the smaller value of cos(α) in the case of the magnetic field B generated by the drain finger 28″, making the fourth sensor 30d insensitive to the magnetic field B generated by the drain finger 28″) and / or contributions from external interferences. Therefore, via the control unit 70, the measurements made by the fourth sensor 30d can be used to compensate for the measurements made by the third sensor 30c (for example, by taking into account the measured magnetic field B from the third sensor 30c). s The measured magnetic field B of the fourth sensor 30d is subtracted from s ), thereby improving the sensitivity and accuracy of the detection. Likewise, the fourth sensor 30d can be arranged so as to measure the contribution of the magnetic field B due to one of the buses 22, 24, in order to cancel said contribution via the control unit 70.

[0084] Furthermore, transistor 20 may be different from the previously described transistors. Specifically, it may be a known type of power device (e.g., a power diode or a microelectronic device). Another example of a power device is described in the paper “Utilizing Advanced Packaging Technologies to Enable Smaller, More Efficient GaN Power Devices” presented by A. Longford et al. at EMPC 2013.

[0085] Furthermore, the sensor 30 may not be operatively coupled to one or more fingers 26, 28, but may extend within the power device so as to be operatively coupled to one or more elements of the transistor 20, the one or more elements being adapted to have a corresponding current to be measured flow therethrough in use. According to one embodiment, the sensor 30 is operatively coupled to one or more busses 22, 24 and enables measurement of the current flowing through the busses 22, 24. Furthermore, with reference to this embodiment, the applicant has discovered that by positioning the sensor 30 transversely with respect to the busses 22, 24 and outside of the interdigitated channels, no significant electromagnetic interference issues arise between the busses 22, 24 and the fingers 26, 28.

[0086] Additionally, the sensor 30 can have a shape different from the cross previously illustrated and can take the form of any of a number of different known embodiments of Hall-effect magnetic sensors (see, for example, “Solid-State Magnetic Sensors,” Handbook of sensors and actuators 2, Chavdar S. Roumenin et al., Elsevier, 1984), including, for example, circular, polygonal (e.g., octagonal or square), and more complex geometries.

[0087] The Hall effect sensor 30 may not even comprise a heterostructure and is therefore not based on a 2DEG. Specifically, it may also be manufactured from corresponding layers of semiconductor materials other than silicon or metallic conductive materials (e.g., aluminum, copper, gold, tungsten, etc.) that are deposited or grown (e.g., epitaxially).

[0088] According to an alternative embodiment, the sensor 30 is not based on the Hall effect, but is a planar magnetic sensor of a type known per se.

[0089] Additionally, semiconductor substrate 42 may be a semiconductor material other than silicon (eg, GaN or GaAs) that provides better adhesion to stack 14 .

[0090] Transistor 20 may also be based on an alternative technology to GaN technology (ie, it may not include one or more GaN layers that participate in electrical conduction); for example, it may be silicon or gallium arsenide or other semiconductor materials.

[0091] Although in the preceding figures and description the arms 7, 8, 9, 10 of the sensor 30 have been indicated as being parallel to the X-axis or Y-axis, this arrangement is not essential and other angular orientations are possible.

[0092] exist Figure 8In another embodiment shown, the previously discussed content is applied to passive devices. Specifically, the power device 401 includes a sensor 30 and a capacitor 420 (specifically, a power capacitor). In this embodiment, the capacitor 420 is made using interdigital electrodes and can have the function of filtering voltage and current peaks in the power circuit (in the power circuit, the peak value can reach a value even ten times higher than the normal operating value, and for example, the peak value of the current can exceed 10A). In fact, such voltage and current peaks may damage the circuit electrically connected to the capacitor 420. The presence of the sensor 30 together with the processing unit 70 makes it possible to reduce the peak value or to disable the circuit that may be damaged. As previously described with reference to power devices 1, 101, 201, and 301, the capacitor 420 in the power device 401 includes: a semiconductor body 405; an insulating region 423 extending on the semiconductor body 405; a plurality of first fingers 426 extending in the insulating region 423 and defining a first plate of the capacitor 420, each first finger 426 having a strip or rectangular shape, with its main extension direction parallel to the axis X; a plurality of second fingers 428 extending in the insulating region 423 and defining a second plate of the capacitor 420, each second finger 428 having a strip shape, with its main extension direction parallel to the axis X; a first bus 422 extending in the insulating region 423 and electrically coupled to the plurality of first fingers 426 for biasing the plurality of first fingers 426; and a second bus 424 extending in the insulating region 423 and electrically coupled to the plurality of second fingers 428 for biasing the plurality of second fingers 428. In detail, each first finger 426 alternates with a second finger 428 along axis Y, faces the second finger 428, and is electrically insulated from the second finger 428, and the sensor 30 is arranged so as to measure a magnetic field B generated at least in part by one of: the first bus 422; the second bus 428; one of the first fingers 426; and one of the second fingers 428. The arrangement of the sensor 30 in the power device 401 is similar to the arrangement previously illustrated and described with reference to the power devices 1, 101, 201, and 301, and therefore will not be described again herein.

[0093] Moreover, even though reference has been made to the Figure 3A A control unit 70 is described, which can also be electrically connected and operatively connected to a power device (specifically, the power device 101, 201, 301, 401) according to any of the various embodiments described above. Additionally, the control unit 70 can be integrated into a die that is separate from the power device 1, 101, 201, 301, 401 and electrically connected to the power device 1, 101, 201, 301, 401.

[0094] The various embodiments described above can be combined to provide other embodiments. These and other changes can be made to the embodiments based on the above detailed description. Generally, in the appended claims, the terms used should not be interpreted as limiting the claims to the specific embodiments disclosed in the description and claims, but should be interpreted to include all possible embodiments and the full scope of equivalents required by such claims. Therefore, the claims are not limited by the disclosure.

Claims

1. A power device, comprising: a first plurality of conductive fingers; a second plurality of conductive fingers, at least one conductive finger of the first plurality of conductive fingers being positioned between two conductive fingers of the second plurality of conductive fingers, the first plurality of conductive fingers being electrically insulated from the second plurality of conductive fingers; a first bus electrically coupled to the first plurality of conductive fingers; a second bus electrically coupled to the second plurality of conductive fingers; as well as a Hall sensor electrically isolated from the first plurality of conductive fingers, the second plurality of conductive fingers, the first bus, and the second bus, wherein the Hall sensor and the conductive element are arranged such that the Hall sensor can detect a magnetic field generated by the conductive element, The magnetic field is indicative of current flowing through the conductive element, and The conductive element is a conductive finger of the first plurality of conductive fingers, a conductive finger of the second plurality of conductive fingers, the first bus, or the second bus.

2. The power device according to claim 1, further comprising: Transistors, including: semiconductor body; source terminal; drain terminal; a gate terminal, the source terminal, the drain terminal, and the gate terminal being electrically coupled to the semiconductor body such that when biased, current flows in the semiconductor body between the drain terminal and the source terminal; an insulating region on the semiconductor body; a first plurality of conductive fingers on the insulating region and electrically coupled to the source terminal, each conductive finger of the first plurality of conductive fingers having a rectangular shape with a main extension direction parallel to a first axis; a second plurality of conductive fingers on the insulating region and electrically coupled to the drain terminal, each conductive finger of the second plurality of conductive fingers having a rectangular shape with a main extension direction parallel to the first axis; a first bus line on the insulating region, the first bus line configured to bias the source terminal; and a second bus bar on the insulating region, the second bus bar being configured to bias the drain terminal, Wherein along a second axis perpendicular to the first axis, each conductive finger of the first plurality of conductive fingers faces and is electrically insulated from a corresponding conductive finger of the second plurality of conductive fingers.

3. The power device according to claim 2, wherein each of the second plurality of conductive fingers comprises: a first major side and a second major side extending parallel to the first axis; as well as a first secondary side and a second secondary side extending parallel to the second axis, wherein each of the first plurality of conductive fingers comprises: a first major side and a second major side extending parallel to the first axis; as well as a first secondary side and a second secondary side extending parallel to the second axis, and wherein the first secondary side of each conductive finger of the first plurality of conductive fingers is electrically connected to the first bus, and the first secondary side of each conductive finger of the second plurality of conductive fingers is electrically connected to the second bus.

4. The power device according to claim 3, further comprising: an insulating layer, wherein the Hall sensor includes a conductive region having a cross shape with a center of mass and extending in a plane defined by the first axis and the second axis, the conductive region being formed in or on the semiconductor body and being electrically insulated from the semiconductor body by the insulating layer.

5. The power device according to claim 4, wherein The semiconductor body includes at least one heterostructure configured to form a two-dimensional electron gas region, and The transistor is a high electron mobility field effect transistor comprising a first portion of the heterostructure, or the conductive region comprises a second portion of the heterostructure electrically insulated from the first portion. The power device according to claim 4 , wherein the conductive element being a conductive finger selected from among the second plurality of conductive fingers, The Hall sensor is arranged such that there is a minimum distance between the centroid and at least one of the first main side or the second main side of the conductive finger selected from among the second plurality of conductive fingers, and The minimum distance is shorter than any other distance between the centroid and each of the first and second major sides of the remaining conductive fingers of the second plurality of conductive fingers.

7. The power device according to claim 4, wherein the conductive element being a conductive finger selected from among the first plurality of conductive fingers, The Hall sensor is arranged such that there is a minimum distance between the centroid and at least one of the first main side or the second main side of the conductive finger selected from among the first plurality of conductive fingers, and The minimum distance is shorter than any other distance between the centroid and each of the first and second major sides of the remaining conductive fingers of the first plurality of conductive fingers.

8. The power device of claim 7, wherein the centroid is closer to the first secondary side of the conductive finger selected from among the first plurality of conductive fingers than to the second secondary side of the conductive finger selected from among the first plurality of conductive fingers. 9 . The power device of claim 7 , wherein the conductive element and the Hall sensor are laterally spaced apart with respect to each other in the planar view. 10 . The power device according to claim 7 , wherein the conductive element and the Hall sensor partially overlap each other in the planar view.

11. The power device according to claim 4, further comprising: Another Hall sensor, the Hall sensor and the another Hall sensor are arranged to face the conductive element in the plane view and are opposite to each other in a direction parallel to the second axis with respect to the conductive element to achieve differential measurement of the magnetic field.

12. The power device according to claim 4, further comprising: Another Hall sensor includes a cross-shaped conductive area with a center of mass, wherein the conductive element and the center of mass of the other Hall sensor overlap each other.

13. The power device according to claim 3, further comprising an insulating layer, wherein: The semiconductor body includes a trench or a protrusion having walls inclined with respect to a plane formed by the first axis and the second axis; The Hall sensor includes a conductive area having a center of mass and extending along the wall, The conductive region is electrically insulated from the semiconductor body by the insulating layer, The conductive element is a conductive finger selected from among the second plurality of conductive fingers or a conductive finger selected from among the first plurality of conductive fingers, The Hall sensor is arranged such that there is a minimum distance between the centroid and at least one of the first main side or the second main side of the conductive finger selected from the second plurality of conductive fingers or the conductive finger selected from the first plurality of conductive fingers, and The minimum distance is shorter than any other distance between the centroid and each of the first and second major sides of remaining conductive fingers among the second plurality of conductive fingers or remaining conductive fingers among the first plurality of conductive fingers.

14. The power device according to claim 2, further comprising: Other conductive elements, including: the conductive element being one of the conductive fingers of the second plurality of conductive fingers or the conductive fingers of the first plurality of conductive fingers directly facing each other along the second axis, The other conductive element is the conductive finger of the second plurality of conductive fingers and another one of the conductive fingers of the first plurality of conductive fingers directly facing each other along the second axis, and In a view of a plane defined by the first axis and the second axis, the Hall sensor is positioned between the conductive fingers of the second plurality of conductive fingers and the conductive fingers of the first plurality of conductive fingers that directly face each other.

15. The power device according to claim 1, further comprising: Capacitors, including: semiconductor body; an insulating region on the semiconductor body; the first plurality of conductive fingers, on the insulating region, the first plurality of conductive fingers being first plates of the capacitor, each conductive finger of the first plurality of conductive fingers having a rectangular shape with a main extension direction parallel to a first axis; the second plurality of conductive fingers, on the insulating region, the second plurality of conductive fingers being second plates of the capacitor, each conductive finger of the second plurality of conductive fingers having a rectangular shape with a main extension direction parallel to the first axis; the first bus bar, on the insulating region, the first bus bar configured to bias the first plurality of conductive fingers; and the second bus, on the insulating region, the second bus configured to bias the second plurality of conductive fingers, Wherein along a second axis perpendicular to the first axis, each conductive finger of the first plurality of conductive fingers faces and is electrically insulated from a corresponding conductive finger of the second plurality of conductive fingers. The power device according to claim 1 , wherein the Hall sensor comprises a two-dimensional electron gas (2DEG) region.

17. A system comprising: Power devices, including: a first plurality of conductive fingers; a second plurality of conductive fingers, at least one conductive finger of the first plurality of conductive fingers being positioned between two conductive fingers of the second plurality of conductive fingers, the first plurality of conductive fingers being electrically insulated from the second plurality of conductive fingers; a first bus electrically coupled to the first plurality of conductive fingers; a second bus electrically coupled to the second plurality of conductive fingers; and a Hall sensor electrically isolated from the first plurality of conductive fingers, the second plurality of conductive fingers, the first bus, and the second bus, wherein the Hall sensor and the conductive element are arranged such that the Hall sensor can detect a magnetic field generated by the conductive element, The magnetic field is indicative of current flowing through the conductive element, and The conductive element is a conductive finger of the first plurality of conductive fingers, a conductive finger of the second plurality of conductive fingers, the first bus, or the second bus; and a control unit operatively coupled to the power device via electrical connections and configured to: acquiring, via the Hall sensor, a Hall potential indicating the magnetic field; calculating a measured magnetic field based on the Hall potential; calculating the magnetic field based on the measured magnetic field; and The calculated magnetic field is correlated with the current of the conductive element.

18. The system of claim 17, wherein Each conductive finger of the first plurality of conductive fingers has a rectangular shape, and Each conductive finger of the second plurality of conductive fingers has a rectangular shape.

19. A method for manufacturing a power device, the method comprising: forming a first plurality of conductive fingers; forming a second plurality of conductive fingers, at least one conductive finger of the first plurality of conductive fingers being positioned between two conductive fingers of the second plurality of conductive fingers, the first plurality of conductive fingers being electrically insulated from the second plurality of conductive fingers; forming a first bus electrically coupled to the first plurality of conductive fingers; forming a second bus electrically coupled to the second plurality of conductive fingers; as well as forming a Hall sensor electrically isolated from the first plurality of conductive fingers, the second plurality of conductive fingers, the first bus bar, and the second bus bar, wherein the Hall sensor and the conductive element are arranged such that the Hall sensor can detect a magnetic field generated by the conductive element, The magnetic field is indicative of current flowing through the conductive element, and The conductive element is a conductive finger of the first plurality of conductive fingers, a conductive finger of the second plurality of conductive fingers, the first bus, or the second bus.

20. The method of claim 19, wherein: Each conductive finger of the first plurality of conductive fingers has a rectangular shape, and Each conductive finger of the second plurality of conductive fingers has a rectangular shape.

21. A method for controlling a power device, the power device being operatively coupled to a control unit, the method comprising: Acquiring, by the control unit, a Hall potential via a Hall sensor of the power device, the Hall potential indicating a magnetic field generated by a current flowing through a conductive element of the power device, the power device comprising: a first plurality of conductive fingers; a second plurality of conductive fingers, at least one conductive finger of the first plurality of conductive fingers being positioned between two conductive fingers of the second plurality of conductive fingers, the first plurality of conductive fingers being electrically insulated from the second plurality of conductive fingers; a first bus electrically coupled to the first plurality of conductive fingers; a second bus electrically coupled to the second plurality of conductive fingers; and the Hall sensor, the Hall sensor being electrically isolated from the first plurality of conductive fingers, the second plurality of conductive fingers, the first bus, and the second bus, wherein the conductive element is a conductive finger of the first plurality of conductive fingers, a conductive finger of the second plurality of conductive fingers, the first bus, or the second bus; Calculating a measurement magnetic field based on the Hall potential by the control unit; calculating, by the control unit, the magnetic field based on the measured magnetic field; and The calculated magnetic field is correlated with the current of the conductive element by the control unit.

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