JP2008016863A - Vertical hall element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical Hall element which allows potential of the Hall element and its vicinity to be kept constant to detect magnetism with higher accuracy. <P>SOLUTION: A conductive film CT made from polycrystalline silicon with conductive impurities added (doped) is formed inside a semiconductor substrate of the Hall element, and the substrate is kept to be ground potential via wiring forming the contact with the conductive film CT. The conductive film CT is, in addition, embedded inside a trench T1 formed on the substrate via an insulating film IL1. This allows a magnetism detection part HP1 to be defined inside the semiconductor substrate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a Hall element, and in particular, a current including a component perpendicular to the surface of a semiconductor substrate (wafer) is supplied to a magnetic detection unit in the semiconductor substrate, and through a Hall voltage generated for the current. The present invention relates to a vertical Hall element that detects a magnetic field component horizontal to the surface of a semiconductor substrate.

  As is well known, since the Hall element can detect the angle without contact, it is used as an angle detection sensor such as a throttle valve opening sensor of an in-vehicle internal combustion engine as a magnetic sensor. Examples of the Hall element include a Hall element as described in Non-Patent Document 1, that is, a horizontal Hall element that detects a magnetic field component perpendicular to a substrate (wafer) surface. Hereinafter, the Hall element (horizontal Hall element) will be described with reference to FIG. FIG. 11A is a plan view of the Hall element, and FIG. 11B is a cross-sectional view taken along line L1-L1 in FIG.

  As shown in FIGS. 11 (a) and 11 (b), this Hall element is formed in a semiconductor substrate (wafer) by, for example, a semiconductor layer (P-sub) 21 made of P-type silicon and epitaxially grown thereon. And an N-type semiconductor region 22 formed by the following steps. Among these, in the semiconductor region 22, a P-type diffusion layer 24 that is connected to the semiconductor layer 21 is formed in order to isolate the Hall element from other elements.

Further, N + diffusion layers 23a to 23d are formed on the surface of the semiconductor region 22 in such a manner that the impurity concentration (N-type) in the same region is selectively increased, and these N + diffusion layers 23a to 23d and the N + diffusion layers 23a to 23d are formed there. An ohmic contact is formed between the arranged electrode (wiring). Then, through each electrode (wiring) forming the ohmic contact, these N +
Diffusion layers 23a-23d and terminals S, G, V1, and V2 are electrically connected to each other. Further, in the N ⁺ diffusion layers 23a to 23d, the N ⁺ diffusion layers 23a and 23b and the N ⁺ diffusion layers 23c and 23d are respectively located at the four corners of the semiconductor region 22 surrounded by the diffusion layer 24 so as to face each other. The region formed and sandwiched between the opposing electrodes is a magnetic detection unit (hole plate) HP2. Furthermore, a ground plate GP2 that is electrically connected to the ground terminal GD is provided in a manner covering the substantially entire surface of the Hall element including the magnetic detection part HP2. As a material of the ground plate GP2, for example, aluminum, polycrystalline silicon doped with a conductive impurity (doped), or the like is employed.

In such a Hall element, for example, when a constant driving current is caused to flow between the terminal S and the terminal G, the current flows on the surface of the semiconductor substrate and mainly has a horizontal component on the surface of the substrate. Including current. Therefore, assuming that a magnetic field (magnetic field indicated by an arrow B in FIG. 11) including a component perpendicular to the surface of the substrate is incident on the magnetic detection unit HP2 of the Hall element in a state where the driving current is passed, Due to the effect, a Hall voltage corresponding to the magnetic field is generated between the terminal V1 and the terminal V2. In this Hall element, the Hall voltage thus generated is detected through the terminals V1 and V2, and V _H = (R _H IB / d) cos θ, R _H = 1 / (qn), which are well-known calculation formulas.
Is used to calculate the magnetic field component to be detected, that is, the magnetic field component perpendicular to the substrate surface of the Hall element. In the above formula, V _H is the Hall voltage, R _H is the Hall coefficient, I is the drive current, B is the magnetic flux density incident on the magnetic detection unit, d is the width of the magnetic detection unit, θ is the Hall element and the magnetic field , Q is the charge, and n is the carrier concentration. As can be seen from the above calculation formula, the Hall voltage V _H changes in accordance with the angle θ formed by the Hall element and the magnetic field. Therefore, by using this, the angle can be detected. Thus, the above-described angle detection sensor can be realized by using the Hall element.

  By the way, the Hall voltage detected in the Hall element is generally a very small voltage, and the Hall element detects a desired magnetism (magnetic field) by accurately measuring a change in the very small voltage. ing. For this reason, the surrounding potential including the Hall element becomes unstable due to, for example, noise from outside the element, charging based on the drive current supplied to the Hall element, drift of the Hall voltage, and the like. If this happens, the fluctuation in the output value of the Hall voltage cannot be ignored, and as a result, there is a concern that the magnetic detection accuracy as the Hall element will be lowered. Therefore, in the horizontal Hall element, by providing the ground plate GP2 that covers substantially the entire surface of the Hall element including the magnetic detection unit HP2, the peripheral potential including the Hall element is fixed to the ground potential. ing. For this reason, the fluctuation of the output value of the Hall voltage is suppressed, and a more stable output voltage can be obtained.

  In recent years, in addition to the horizontal Hall element, a Hall element that detects a magnetic field component horizontal to the surface of the substrate (wafer), a so-called vertical Hall element has been studied. Since this vertical Hall element has a feature that two elements having different phase differences can be integrated on one chip, by arranging the two vertical Hall elements so as to form an angle of 90 °, A rotation sensor capable of obtaining a linear output in an angle range of 360 ° can also be realized. An example of such a vertical Hall element is disclosed in Patent Document 1. Hereinafter, an example of the vertical Hall element will be described with reference to FIG. In FIG. 12, FIG. 12 (a) is a plan view of the Hall element, and FIG. 12 (b) is a cross-sectional view taken along line L1-L1 of FIG. 12 (a).

  As shown in FIGS. 12A and 12B, this Hall element has a semiconductor layer (P-sub) 31 made of, for example, P-type silicon in a semiconductor substrate (wafer), and its surface. An N-type impurity is introduced to form a buried layer BL3, and an N-type semiconductor region 32 is formed thereon by epitaxial growth. The buried layer BL3 functions as a lower electrode, and its impurity concentration is set higher than that of the semiconductor region 32.

Further, N ⁺ diffusion layers 33a to 33e are formed on the surface of the semiconductor region 32 in such a manner that the impurity concentration (N-type) in the region is selectively increased, and these N ⁺ diffusion layers 33a to 33e and An ohmic contact is formed between the arranged electrode (wiring). The N ⁺ diffusion layers 33a to 33e and the terminals S, G1, G2, V1, and V2 are electrically connected to each other through the electrodes (wirings) that form the ohmic contact. In addition, a P-type diffusion layer 34 connected to the semiconductor layer 31 is formed around the N ⁺ diffusion layers 33a to 33e, which isolates the Hall element from other elements. . Also here, as will the N ⁺ diffusion layer 33a becomes a shape which is sandwiched with both the N ⁺ diffusion layers 33d and 33e perpendicular thereto and the N ⁺ diffusion layers 33b and 33c, further these, N ⁺ diffusion The layers 33a, 33d, and 33e are surrounded by a trench T3 that is connected to the buried layer BL3. In this Hall element, a region sandwiched between the N ⁺ diffusion layers 33d and 33e in the enclosed region (electrically partitioned region) is a so-called magnetic detection unit (hole plate) HP3. Become. Note that a conductive impurity is introduced into the inner wall of the trench T3 to form a P-type diffusion layer DF3, and, for example, a polycrystalline (non-doped) with no conductive impurity added therein is formed in the trench T3. An insulating film IL3 made of silicon is embedded.

In such a Hall element, for example, when a constant driving current is passed between the terminal S and the terminal G1 and between the terminal S and the terminal G2, the current is formed on the surface of the semiconductor substrate. It flows from the N ⁺ diffusion layer 33a to the N ⁺ diffusion layers 33b and 33c through the buried layer BL3. That is, the drive current flowing through the magnetic detection unit HP3 in the semiconductor substrate is a current mainly including a component perpendicular to the surface of the substrate. Therefore, assuming that a magnetic field including a horizontal component on the surface of the substrate (magnetic field indicated by an arrow B in FIG. 12) is incident on the magnetic detection unit HP3 of the Hall element in a state where this driving current is applied, Due to the effect, a Hall voltage corresponding to the magnetic field is generated between the terminal V1 and the terminal V2. Also in this Hall element, the Hall voltage thus generated is detected through the terminals V1 and V2, and the above formula “V _H = (R _H IB / d) cos θ, similarly to the Hall element illustrated in FIG. Is used to calculate a magnetic field component to be detected, that is, a magnetic field component horizontal to the surface of the substrate of the Hall element. Incidentally, in this Hall element, the dimension d shown in FIG. 12A corresponds to “d” in the above formula.
Ichisuke Maenaka, 3 others, "Integrated 3D magnetic sensor", IEEJ Transactions C, 1989, Vol. 109, No. 7, p483-490 Japanese Patent Laid-Open No. 1-251763

  By the way, also in the vertical Hall element, the Hall voltage detected here is a very small value, and as described above, there is a concern that the magnetic detection accuracy as the Hall element is lowered. Therefore, it is conceivable to provide a ground plate for such a vertical Hall element as well as the horizontal Hall element illustrated in FIG. However, in the vertical Hall element, since the magnetic detection part (Hall plate) is formed not only on the surface of the substrate but also on the inside thereof, even if a ground plate is provided to cover the surface of the substrate, it is still sufficient. The effect has not yet been achieved.

  The present invention has been made in view of such circumstances, and provides a vertical Hall element that can fix magnetic potential with high accuracy by fixing the potential around the Hall element. Objective.

  In order to achieve such an object, according to the first aspect of the present invention, a current containing a component perpendicular to the surface of the semiconductor substrate is supplied to the magnetic detector in the semiconductor substrate and is generated with respect to the current. As a vertical Hall element that detects a magnetic field component horizontal to the surface of the semiconductor substrate through a Hall voltage, the semiconductor substrate has one or more conductive layers therein, and contacts are formed with the conductive layers. The conductive layer is fixed to an arbitrary potential via wiring, and the conductive layer is a conductive film material embedded through an insulating film in a trench formed in the semiconductor substrate.

  According to such a structure, the potential around the Hall element including the Hall element is fixed through one or more conductive layers formed in the semiconductor substrate. In addition, since the conductive layer is provided inside the semiconductor substrate, the potential is fixed not only on the surface of the substrate but also on the inside of the semiconductor substrate including the magnetic detection part (hole plate). Will be able to. That is, by adopting the above-described structure, a stable output voltage can be obtained, and as a result, the magnetic detection accuracy as the Hall element can be maintained high. Further, the conductive film material is made of, for example, a metal material or a semiconductor material to which a conductive impurity is added, and is embedded in an insulating film inside a trench formed in the semiconductor substrate. The conductive layer can be easily formed.

  In this case, the conductive film material may be made of polycrystalline silicon doped with a conductivity type impurity (doped) as in the invention described in claim 2. This is particularly effective in making the layer formation easier.

  According to a third aspect of the present invention, a current including a component perpendicular to the surface of the semiconductor substrate is supplied to the magnetic detection unit in the semiconductor substrate, and the Hall voltage generated for the current is applied to the semiconductor substrate. As a vertical Hall element that detects a magnetic field component that is horizontal on the surface, the semiconductor substrate has one or a plurality of conductive layers therein, and an arbitrary potential via a wiring that forms a contact with the conductive layer. And the conductive layer is formed of a diffusion layer formed by adding a conductive impurity to the semiconductor substrate, and the P-type and N-type diffusion layers are at least as the conductive layer. One set is a structure arranged adjacent to the outer periphery of the Hall element.

  According to such a structure, the potential around the Hall element including the Hall element is fixed through one or more conductive layers formed in the semiconductor substrate. In addition, since the conductive layer is provided inside the semiconductor substrate, the potential is fixed not only on the surface of the substrate but also on the inside of the semiconductor substrate including the magnetic detection part (hole plate). Will be able to. That is, by adopting the above-described structure, a stable output voltage can be obtained, and as a result, the magnetic detection accuracy as the Hall element can be maintained high. Moreover, the conductive layer is made easier by forming the conductive layer as a diffusion layer formed by adding a conductive impurity to the semiconductor substrate.

  As described above, noise from the outside is one of the causes that make the potential of the Hall element unstable. Such external noise includes those having a positive (plus) polarity and those having a negative (minus) polarity. Therefore, if the P-type and N-type diffusion layers are arranged adjacent to each other on the outer periphery of the Hall element as in the above-described structure, even if it has a positive or negative polarity, Are absorbed by the adjacent P-type and N-type diffusion layers. For this reason, an IC (integrated circuit) chip in which a peripheral circuit (for example, a detection circuit of a magnetic sensor) or the like is built with the Hall element is also free from noise from the peripheral circuit in the same chip or noise from outside the chip. The resistance will be further strengthened.

  With respect to the vertical Hall element according to any one of the above 1-3, as described in claim 4, the semiconductor substrate is connected to a power supply potential and a ground potential via a wiring that forms a contact with the conductive layer. It is more effective to make the structure fixed to either one of the above. By adopting such a structure, the potential of the Hall element can be more easily and suitably fixed.

  Furthermore, regarding the vertical Hall element according to any one of the first to fourth aspects, as in the invention according to the fifth aspect, the conductive layer is divided and the magnetic detection unit is partitioned in the semiconductor substrate. It is effective to form a potential barrier portion to be formed.

  As can be seen in the vertical Hall element illustrated in FIG. 12, the magnetic detection portion (Hall plate) in the vertical Hall element is usually partitioned in the semiconductor substrate by a potential barrier portion made of, for example, a trench or a diffusion layer. It is formed. Therefore, if the conductive layer is used as such a potential barrier portion as in the above structure, the magnetic detection portion of the Hall element and its surrounding potential can be fixed (stabilized). Magnetic detection accuracy as a Hall element can be maintained higher. Incidentally, in the Hall element illustrated in FIG. 12, the trench T3 and the insulating film buried in the trench T3 correspond to the potential barrier portion.

  On the other hand, as for the invention according to any one of claims 1 to 4, as in the invention according to claim 6, as the conductive layer, an element isolation portion that isolates the Hall element from other elements. It is also effective to use

  When forming a vertical Hall element on a semiconductor substrate, the Hall element is usually isolated from other surrounding elements by an element isolation portion made of, for example, a trench or a diffusion layer. Therefore, it is also effective to use such an element isolation portion as the conductive layer. Incidentally, in the vertical Hall element illustrated in FIG. 12, the diffusion layer 34 corresponds to this element isolation portion.

  With regard to the invention according to any one of claims 1 to 6, as in the invention according to claim 7, a conductor plate fixed at an arbitrary potential is provided on the semiconductor substrate at least in the magnetic field. By adopting a structure in which the detection portion is covered, the potential of the surface of the semiconductor substrate of the Hall element is also fixed (stabilized). In addition, noise from the upper portion of the semiconductor substrate can be shielded to protect the Hall element from noise. Furthermore, in the vertical Hall element, mobile ions such as sodium (Na) in the interlayer insulating film formed on the surface of the semiconductor substrate move with the energization or temperature change of the Hall element, and are detected by the Hall element. The output value of the very small Hall voltage that is generated may be staggered. Also in this respect, if the above structure is adopted, the potential of the surface of the semiconductor substrate is fixed, so that the movement of mobile ions in the interlayer insulating film formed on the surface is suppressed, and consequently The fluctuation of the output value of the Hall voltage is suppressed. Thus, according to the above structure, the magnetic detection accuracy as the Hall element is maintained higher.

  Further, in this case, for example, when used in combination with the structure described in claim 5, the periphery of the magnetic detection portion of the Hall element is substantially completely surrounded by the conductive layer and the conductor plate. That is, with such a structure, the magnetic detection accuracy as the Hall element is maintained at a higher level.

  In this case as well, the potential of the conductor plate can be fixed arbitrarily. However, as described in claim 8, the conductor plate is preferably fixed to one of a power supply potential and a ground potential. It is valid. With such a structure, the potential of the Hall element can be more easily and suitably fixed.

  And about invention of any one of Claims 1-8, like the invention of Claim 9, the said semiconductor substrate is formed in the form in which the conductivity type impurity is added to the same substrate. The present invention is particularly effective when applied to a structure having a semiconductor region in which the magnetic detection portion is formed in the semiconductor region.

  For example, in the vertical Hall element exemplified in FIG. 12, an epitaxial film (semiconductor region 32) is used as the semiconductor region. For this reason, an epitaxial growth process is required as a manufacturing process thereof, and as a result, the manufacturing process of the Hall element is complicated. Further, if an epitaxial substrate on which an epitaxial film is formed in advance is used in order to avoid such a complicated manufacturing process, the cost of the substrate is unavoidable. In this regard, as in the above structure, if the semiconductor region formed with the conductivity type impurity is added to the semiconductor substrate as the semiconductor region in which the magnetic detection unit is formed, It can be manufactured by a CMOS (Complementary Metal Oxide Semiconductor) process. For example, when a CMOS circuit is employed as the peripheral circuit of the Hall element, the manufacturing process can be shared with the peripheral circuit. .

(First embodiment)
FIG. 1 shows a first embodiment of a vertical Hall element according to the present invention.
Similarly to the vertical Hall element illustrated in FIG. 12, the vertical Hall element according to this embodiment detects a magnetic field component that is horizontal with respect to the substrate (wafer) surface. One hall element can be integrated on one chip. However, in the vertical Hall element of this embodiment, the structure shown in FIG. 1 is used to fix the potential around the Hall element including the Hall element, thereby improving the magnetic detection accuracy.

  The structure of the vertical Hall element according to this embodiment will be described in detail below with reference to FIG. 1A is a plan view of the Hall element, FIG. 1B is a cross-sectional view taken along line L1-L1 in FIG. 1A, and FIG. 1C is FIG. It is sectional drawing which expands and shows the area | region A shown by the dashed-dotted line in (b).

  As shown in FIGS. 1A to 1C, this Hall element also has a semiconductor layer (P-sub) 11 made of, for example, P-type silicon in a semiconductor substrate (wafer). An N-type impurity is introduced to form a buried layer BL1, and an N-type semiconductor region 12 is formed thereon by epitaxial growth. The buried layer BL1 functions as a lower electrode, and its impurity concentration is set higher than that of the semiconductor region 12. In general, a semiconductor material such as silicon has a higher carrier mobility in an N-type semiconductor than in a P-type semiconductor. Therefore, in the vertical Hall element according to this embodiment, an N-type semiconductor material (silicon) is used as the material of the semiconductor region 12, thereby increasing the sensitivity of the Hall element.

Further, N ⁺ diffusion layers 13a to 13e are formed on the surface of the semiconductor region 12 in such a manner that the impurity concentration (N type) of the same region is selectively increased, and these N ⁺ diffusion layers 13a to 13e and An ohmic contact is formed between the arranged electrode (wiring). The N ⁺ diffusion layers 13a to 13e and the terminals S, G1, G2, V1, and V2 are electrically connected to each other through the electrodes (wirings) that form the ohmic contact. A P-type diffusion layer (element isolation portion) 14 that is connected to the semiconductor layer 11 is formed around the N ⁺ diffusion layers 13a to 13e, and this Hall element is connected to other elements. The element is isolated. Also here, this is for the N ⁺ diffusion layer 13a is, the N ⁺ will form sandwiched both between the diffusion layer 13b and 13c and the N ⁺ diffusion layers 13d and 13e perpendicular thereto, further these, N ⁺ diffusion The layers 13a, 13d, and 13e are surrounded by a trench T1 that reaches the buried layer BL1. In this Hall element, a region sandwiched between the N ⁺ diffusion layers 13d and 13e in the enclosed region (electrically partitioned region) is a so-called magnetic detection unit (hole plate) HP1. Become.

  In addition, in this Hall element, an insulating film IL1 made of, for example, silicon oxide is formed on the inner wall of the trench T1 that defines the magnetic detection unit HP1, and the insulating film IL1 is interposed through the insulating film IL1. For example, a conductive film material (conductive layer) CT made of polycrystalline silicon to which a conductive impurity is added (doped) is embedded. The conductive film material CT is electrically connected to the ground terminal GD through a wiring that forms a contact with the conductive film material CT. In the Hall element, the trench T1, the insulating film IL1 and the conductive film material CT formed therein correspond to a potential barrier portion.

Also in the vertical Hall element according to this embodiment, for example, when a constant driving current is passed between the terminal S and the terminal G1 and between the terminal S and the terminal G2, the current is supplied to the semiconductor substrate. Flows from the N ⁺ diffusion layer 13a formed on the surface to the N ⁺ diffusion layers 13b and 13c through the buried layer BL1. That is, the drive current flowing through the magnetic detection unit HP1 in the semiconductor substrate is a current mainly including a component perpendicular to the surface of the substrate. Therefore, assuming that a magnetic field (magnetic field indicated by an arrow B in FIG. 1) including a horizontal component on the surface of the substrate is incident on the magnetic detection unit HP1 of the Hall element in a state where the driving current is passed, Due to the effect, a Hall voltage corresponding to the magnetic field is generated between the terminal V1 and the terminal V2. Also in this Hall element, the Hall voltage thus generated is detected through these terminals V1 and V2, and the above formula “V _H = (R _H IB / d) cos θ, similarly to the Hall element illustrated in FIG. Is used to calculate a magnetic field component to be detected, that is, a magnetic field component horizontal to the surface of the substrate of the Hall element. Incidentally, in this Hall element, the dimension d shown in FIG. 1A corresponds to “d” in the above formula.

  Thus, in the vertical Hall element according to this embodiment, the semiconductor substrate of the Hall element is fixed to the ground potential through the conductive film material CT formed in the same substrate. Moreover, since the conductive film material CT is provided inside the semiconductor substrate, not only the surface of the substrate but also the inside of the semiconductor substrate including the magnetic detection unit HP1 is fixed to the ground potential. Will be able to. That is, with such a structure, a stable output voltage can be obtained, and as a result, the magnetic detection accuracy as the Hall element can be maintained high.

As described above, according to the vertical Hall element according to this embodiment, the following excellent effects can be obtained.
(1) The semiconductor substrate of the Hall element has a conductive film material (conductive layer) CT therein, and is fixed to the ground potential via a wiring that forms a contact with the conductive film material CT. The structure. By doing so, the potential around the Hall element including the Hall element is fixed to the ground potential, and magnetic detection with higher accuracy becomes possible.

(2) Also, by fixing the substrate to the ground potential, the potential of the Hall element can be more easily and suitably fixed.
(3) In addition, by increasing the magnetic detection accuracy, the yield as a Hall element can be improved, leading to cost reduction and energy saving.

  (4) In fixing the potential of the semiconductor substrate, it is buried in the trench T1 formed in the substrate through the insulating film IL1, and is doped with doped impurities (doped). A conductive film material CT is used. This facilitates the realization of the above structure.

  (5) Further, the conductive film material CT has a structure that serves as a potential barrier section that partitions and forms the magnetic detection section HP1 inside the semiconductor substrate. Thereby, the magnetic detection part HP1 of the Hall element and the surrounding potential are fixed (stabilized) to the ground potential, and the magnetic detection accuracy as the Hall element can be maintained higher. become.

(Second Embodiment)
FIG. 2 shows a second embodiment of the vertical Hall element according to the present invention.
Hereinafter, the structure of the vertical Hall element according to this embodiment will be described mainly with respect to differences from the vertical Hall element according to the first embodiment described above with reference to FIG. 2A is a plan view of the Hall element, FIG. 2B is a cross-sectional view taken along line L1-L1 in FIG. 2A, and FIG. 2C is FIG. It is sectional drawing which expands and shows the area | region A shown by the dashed-dotted line in (b). In FIG. 2, the same elements as those shown in FIG. 1 are denoted by the same reference numerals, and overlapping descriptions of these elements are omitted.

  As shown in FIGS. 2 (a) to 2 (c), this Hall element also basically has the same structure as the vertical Hall element of the first embodiment illustrated in FIG. The operation mode is also as described above. However, here, a conductive impurity is introduced into the inner wall of the trench T1 formed in the semiconductor substrate to form a P-type diffusion layer (conductive layer) DF11. The diffusion layer DF11 is also electrically connected to the ground terminal GD through a wiring that forms a contact with the conductive film material CT, similarly to the conductive film material CT. In this Hall element, in addition to the previous trench T1 and the insulating film IL1 and the conductive film material CT formed therein, the diffusion layer DF11 also partitions the magnetic detection part HP1 in the semiconductor substrate. This corresponds to the potential barrier portion to be formed.

By the way, when a trench is formed in a semiconductor substrate, a damage layer is formed on the inner wall of the trench, and carrier recombination is likely to occur there. In this regard, in the above structure, since the diffusion layer DF11 is formed on the inner wall of the trench T1, recombination of such carriers is suppressed. In the vertical Hall element according to this embodiment, the diffusion layer DF11 formed on the inner wall of the trench T1 is fixed to the ground potential together with the conductive film material CT. The fixation of becomes stronger. Further, since this diffusion layer DF11 is used as a potential barrier part for partitioning and forming the magnetic detection part HP1 in the semiconductor substrate, “V _H = (R _H IB / d) cos θ” The dimension corresponding to “d” is substantially narrowed, and as a result, the sensitivity of magnetic detection by the Hall element is further increased.

  As described above, according to the vertical Hall element according to the second embodiment, effects similar to or equivalent to the effects (1) to (5) according to the first embodiment are achieved. The following effects can also be newly obtained.

  (6) The diffusion layer DF11 formed on the inner wall of the trench T1 is also fixed to the ground potential. As a result, the fixation of the potential of the Hall element becomes stronger.

  (7) Further, the diffusion layer DF11 has a structure that becomes a potential barrier part that partitions and forms the magnetic detection part HP1 in the semiconductor substrate. Thereby, it is possible to further increase the sensitivity of magnetic detection by the Hall element.

(Third embodiment)
FIG. 3 shows a third embodiment of the vertical Hall element according to the present invention.
Hereinafter, the structure of the vertical Hall element according to this embodiment will be described mainly with respect to differences from the vertical Hall element according to the first embodiment described above with reference to FIG. 3A is a plan view of the Hall element, FIG. 3B is a sectional view taken along line L1-L1 in FIG. 3A, and FIG. 3C is FIG. It is sectional drawing which expands and shows the area | region A shown by the dashed-dotted line in (b). In FIG. 3, the same elements as those shown in FIG. 1 are denoted by the same reference numerals, and redundant descriptions of these elements are omitted.

  As shown in FIGS. 3A to 3C, this Hall element also basically has the same structure as the vertical Hall element of the first embodiment illustrated in FIG. The operation mode is also as described above. However, here, instead of the trench T1, the insulating film IL1, and the conductive film material CT, a P-type diffusion layer (conductive layer) DF12 connected to the buried layer BL1 is used as the potential barrier portion. Yes. Specifically, by forming such a P-type diffusion layer DF12 in the N-type semiconductor region 12, a pn junction (potential barrier) is formed between the two, and the inside of the semiconductor substrate Thus, the magnetic detection part (hole plate) HP1 is partitioned. In the vertical Hall element of this embodiment, the diffusion layer DF12 is electrically connected to the ground terminal GD through a wiring that forms a contact with the diffusion layer DF12.

  Even with such a structure, similarly to the Hall element illustrated in FIG. 1, the potential around the Hall element including the Hall element is fixed, and magnetic detection with higher accuracy is possible.

  As described above, the vertical Hall element according to the third embodiment also obtains the same or similar effects as the effects (1) to (5) of the previous first embodiment. be able to.

(Fourth embodiment)
FIG. 4 shows a fourth embodiment of a vertical Hall element according to the present invention.
Hereinafter, the structure of the vertical Hall element according to this embodiment will be described mainly with respect to differences from the vertical Hall element according to the first embodiment described above with reference to FIG. 4A is a plan view of the Hall element, and FIG. 4B is a cross-sectional view taken along line L1-L1 in FIG. 4A. In FIG. 4, the same elements as those shown in FIG. 1 are denoted by the same reference numerals, and redundant descriptions of these elements are omitted.

  As shown in FIGS. 4 (a) to 4 (b), this Hall element also basically has the same structure as the vertical Hall element of the first embodiment illustrated in FIG. The operation mode is also as described above. However, here, a conductor plate (ground plate) GP1 that is electrically connected to the ground terminal GD is provided so as to cover substantially the entire surface of the Hall element including the magnetic detection unit (hole plate) HP1. The conductor plate GP1 is formed via an interlayer insulating film (not shown) formed on the surface of the semiconductor substrate. Further, the diffusion layer (element isolation portion) 14 that isolates the Hall element from the surrounding elements is also electrically connected to the ground terminal GD, like the conductor plate GP1. As a material of the conductor plate GP1, for example, aluminum, polycrystalline silicon doped with a conductive impurity (doped), or the like is employed.

  Thus, by arranging the conductor plate GP1 fixed to the ground potential so as to cover almost the entire surface of the Hall element including the magnetic detection part HP1, the potential of the surface of the semiconductor substrate of the Hall element is also reduced. It becomes fixed (stable). In addition, noise from the upper part of the semiconductor substrate can be shielded to protect the Hall element from noise. In addition, the periphery of the magnetic detection part HP1 of the Hall element is almost completely surrounded by the conductive film material (conductive layer) CT fixed to the ground potential and the conductor plate GP1. As a result, the magnetic detection accuracy as the Hall element is maintained at a higher level. Here, the diffusion layer 14 that isolates the Hall element from other surrounding elements is also fixed to the ground potential, so that the fixation of the potential of the Hall element is stronger. It has become.

  In the vertical Hall element, mobile ions such as sodium (Na) in the interlayer insulating film formed on the surface of the semiconductor substrate move as the Hall element is energized or temperature changes, and is detected by the Hall element. The output value of the very small Hall voltage that is generated may be staggered. In this regard, according to the above structure, since the potential of the surface of the semiconductor substrate is fixed, the position of charges such as mobile ions is also fixed, and consequently fluctuations in the output value of the Hall voltage, drift phenomenon, etc. are suppressed. It will be done.

  As described above, according to the vertical Hall element according to the fourth embodiment, effects similar to or equivalent to the effects (1) to (5) according to the first embodiment are achieved. The following effects can also be newly obtained.

  (8) The conductor plate GP1 fixed to the ground potential is arranged so as to cover substantially the entire surface of the Hall element including the magnetic detection unit HP1. Thereby, the potential of the surface of the semiconductor substrate of the Hall element is also fixed (stable). In addition, noise from the top of the semiconductor substrate can be shielded to protect the Hall element from noise, and the position of charges such as movable ions can be fixed. Magnetic detection accuracy as an element is maintained higher.

  (9) A structure in which the periphery of the magnetic detection part HP1 of the Hall element is substantially completely surrounded by the conductive film material (conductive layer) CT and the conductor plate GP1 fixed to the ground potential. As a result, the magnetic detection accuracy as the Hall element is maintained at a higher level.

  (10) The diffusion layer 14 that separates the Hall element from other surrounding elements is also configured to be fixed to the ground potential. Thereby, the fixation of the potential of the Hall element becomes stronger.

(Fifth embodiment)
FIG. 5 shows a fifth embodiment of a vertical Hall element according to the present invention.
Hereinafter, the structure of the vertical Hall element according to this embodiment will be described mainly with respect to differences from the vertical Hall element according to the third embodiment. 5A, FIG. 5A is a plan view of the Hall element, FIG. 5B is a cross-sectional view taken along line L1-L1 in FIG. 5A, and FIG. 5C is FIG. It is sectional drawing which expands and shows the area | region A shown by the dashed-dotted line in (b). In FIG. 5, the same elements as those shown in FIG. 3 are denoted by the same reference numerals, and overlapping descriptions of these elements are omitted.

  As shown in FIGS. 5A to 5C, this Hall element basically also has a structure substantially similar to the Hall element of the third embodiment illustrated in FIG. The operation mode is also as described above. However, here, the buried layer BL1 is omitted, and a conductive impurity is added to the semiconductor substrate instead of the semiconductor region 12 formed by epitaxial growth on the semiconductor layer 11. A semiconductor region 12a formed in a shape is used. In the Hall element, the magnetic detection part (hole plate) HP1 is partitioned and formed in the semiconductor region 12a by the P-type diffusion layer (conductive layer) DF12. As described above, the diffusion layer DF12 that partitions and forms the magnetic detection unit HP1 is electrically connected to the ground terminal GD through a wiring that forms a contact with the diffusion layer DF12.

  Since the vertical Hall element according to this embodiment has the above-described structure, it can be manufactured in a normal CMOS (Complementary Metal Oxide Semiconductor) process. For example, when a CMOS circuit is employed as the peripheral circuit of the Hall element, the manufacturing process can be shared with the peripheral circuit.

  As described above, according to the vertical Hall element according to the fifth embodiment, effects similar to or equivalent to the effects (1) to (5) according to the first embodiment are achieved. The following effects can also be newly obtained.

  (11) A semiconductor substrate of the Hall element has a semiconductor region 12a formed by adding a conductivity type impurity to the substrate, and a magnetic detection part (hole plate) HP1 is formed in the semiconductor region 12a. The structure is as follows. Thus, the Hall element can be manufactured by a normal CMOS process. For example, when a CMOS circuit is employed as the peripheral circuit of the Hall element, the manufacturing process can be shared with the peripheral circuit. It becomes like this.

(Sixth embodiment)
FIG. 6 shows a sixth embodiment of a vertical Hall element according to the present invention.
Hereinafter, the structure of the vertical Hall element according to this embodiment will be described mainly with respect to differences from the vertical Hall element of the fifth embodiment described above with reference to FIG. In FIG. 6, FIG. 6A is a plan view of the Hall element, and FIG. 6B is a cross-sectional view taken along line L1-L1 of FIG. 6A. In FIG. 6, the same elements as those shown in FIG. 5 are denoted by the same reference numerals, and redundant descriptions of these elements are omitted.

  As shown in FIGS. 6 (a) and 6 (b), this Hall element also basically has the same structure as the vertical Hall element of the fifth embodiment illustrated in FIG. The operation mode is also as described above. However, here, a diffusion layer is further provided outside the element isolation diffusion layer 14 so that a P-type diffusion layer (conductive layer) 14 and an N-type diffusion layer (conductive layer) are formed on the outer periphery of the Hall element. ) 14a and a P-type diffusion layer (conductive layer) 14b are arranged adjacent to each other. For these diffusion layers 14 and 14a and 14b, the diffusion layers 14 and 14b are electrically connected to the ground terminal GD and the diffusion layer 14a is electrically connected to the power supply terminal PS via appropriate wirings.

  As described above, external noise is one of the causes that make the Hall element potential unstable. Some of these external noises have positive (plus) polarity, and negative ( Some have a negative polarity. Therefore, if the P-type and N-type diffusion layers are arranged adjacent to each other on the outer periphery of the Hall element as in the above-described structure, even if it has a positive or negative polarity, Is absorbed by the adjacent P-type and N-type diffusion layers. For this reason, an IC (integrated circuit) chip in which a peripheral circuit (for example, a detection circuit of a magnetic sensor) or the like is built with the Hall element is also free from noise from the peripheral circuit in the same chip or noise from outside the chip. The resistance will be further strengthened.

  As described above, according to the magnetic sensor according to the sixth embodiment, the above-mentioned (1) to (5) and (10) and (10) according to the first, fourth, or fifth embodiment. The effect similar to or equivalent to the effect of 11) can be obtained, and the following effect can be newly obtained.

  (12) The P-type diffusion layer 14, the N-type diffusion layer 14a, and the P-type diffusion layer 14b are arranged adjacent to each other on the outer periphery of the Hall element. As a result, even with an IC (integrated circuit) chip in which a peripheral circuit (for example, a detection circuit of a magnetic sensor) and the like are formed together with the Hall element, noise from the peripheral circuit in the same chip or noise from the outside of the chip The resistance will be further strengthened.

(Other embodiments)
In addition, each said embodiment can also be implemented with the following aspects.
In the first to third and fifth embodiments, the diffusion layer (element isolation portion) 14 that isolates the Hall element from other elements may be fixed to the ground potential. By adopting such a structure, it is possible to obtain an effect similar to or equivalent to the effect (10) of the fourth embodiment. For example, when this structure is applied to the vertical Hall element of the first embodiment, the structure shown in FIG. 7 is obtained. FIG. 7 is a cross-sectional view corresponding to FIG.

  In each of the above embodiments, the diffusion layer 14 formed by adding a conductivity type impurity to the semiconductor substrate is used as an element isolation part that isolates the Hall element from other elements. Instead of this, trench isolation may be used. Further, in this case, as the element isolation trench, for example, in the vertical Hall element of the first embodiment, the trench T1 that partitions and forms the magnetic detection unit HP1 is interposed with an insulating film inside the trench. In addition, a material in which a conductive film material is embedded can be used. Further, in this case as well, by fixing the conductive film material embedded in the trench to the ground potential, an effect similar to or equivalent to the effect (10) of the fourth embodiment can be obtained. It becomes like this. For example, when this structure is applied to the vertical Hall element of the first embodiment, a structure as shown in FIG. 8 is obtained. 8 is a cross-sectional view corresponding to FIG. 1B. The trench T1a, the insulating film IL1a, and the conductive film material CTa in FIG. 8 are the trench T1 and the insulating film in FIG. It corresponds to IL1 and conductive film material CT, respectively. In addition, as the element isolation trench, for example, a conductive impurity is introduced into the inner wall of the vertical Hall element of the second embodiment, such as the trench T1 that partitions and forms the magnetic detection part HP1. Alternatively, a diffusion layer formed may be used. With such a structure, an effect similar to or equivalent to the effect (6) of the second embodiment can be obtained.

  In the vertical Hall element of the fourth embodiment, the conductor plate GP1 is fixed to the ground potential. However, the present invention is not limited to this. For example, the plate GP1 is fixed to the power supply potential. Also good.

Further, the conductor plate GP1 does not need to cover substantially the entire surface of the Hall element, and it is sufficient if it covers at least the magnetic detection part (Hall plate).
The conductor plate GP1 that covers the substantially entire surface of the Hall element including the magnetic detection portion in the vertical Hall element of the fourth embodiment is formed by the second, third, fifth, and sixth embodiments. Even if the structure is applied to the vertical Hall element of the embodiment, it is possible to obtain an effect similar to or equivalent to the effect (8) and the effect (9) of the fourth embodiment. Become. For example, when this structure is applied to the vertical Hall element of the fifth embodiment, a structure as shown in FIG. 9 is obtained. FIG. 9 is a cross-sectional view corresponding to FIG.

  In the sixth embodiment, the diffusion layers 14 and 14b are electrically connected to the ground terminal GD, and the diffusion layer 14a is electrically connected to the power supply terminal PS. However, the present invention is not limited to this, and for example, the diffusion layers 14 and 14a and 14b may be configured to be electrically connected to the ground terminal GD.

  In the sixth embodiment, three diffusion layers such as a P-type diffusion layer 14, an N-type diffusion layer 14a, and a P-type diffusion layer 14b are adjacent to each other on the outer periphery of the Hall element. It was set as the structure arrange | positioned by. However, the present invention is not limited to this structure, and any structure of the sixth embodiment can be used as long as at least one pair of P-type and N-type diffusion layers is disposed adjacent to the outer periphery of the Hall element. An effect similar to or equivalent to the effect of (12) can be obtained. For example, as shown in FIG. 10, in the vertical Hall element according to the sixth embodiment, the diffusion layer 14b may be omitted. FIG. 10 is a cross-sectional view corresponding to FIG. 6B. Also in this case, the diffusion layers 14 and 14a may both be electrically connected to the ground terminal GD. Conversely, the number of the diffusion layers may be increased and four or more P-type and N-type diffusion layers may be arranged adjacent to the outer periphery of the Hall element.

  In the first, second, and fourth embodiments, a conductive impurity is added as a material for the conductive film material (conductive layer) CT embedded in the trench T1 via the insulating film IL1. Polycrystalline silicon (doped) was used. However, the material of the conductive film material CT is not limited to this. For example, a metal material such as copper or aluminum, or a material obtained by adding a conductive impurity to a semiconductor material other than polycrystalline silicon can be used as appropriate.

  In the vertical Hall element according to each of the above embodiments, the present invention is similarly applied to a structure in which the conductivity type of each element constituting the semiconductor substrate is switched, that is, a structure in which the P type and the N type are switched. be able to. In addition, as the semiconductor substrate, for example, an SOI (Silicon On Insulator) substrate, a multiple diffusion layer substrate such as P-type-N-type-P type or N-type-P-type-N type can be appropriately employed.

  In each of the above embodiments, silicon is used as the material for the semiconductor substrate, but other materials may be appropriately employed depending on the manufacturing process, structural conditions, and the like. For example, a compound semiconductor material such as GaAs, InSb, InAs, or a semiconductor material such as Ge (germanium) can be used. In particular, GaAs and InAs are materials having excellent temperature characteristics, and are effective in increasing the sensitivity of the Hall element.

  In each of the above embodiments, the semiconductor substrate of the Hall element is fixed to the ground potential or the power supply potential. However, the present invention is not limited to this, and the potential fixed to the substrate is arbitrary.

  In each of the above embodiments, the potential of the semiconductor substrate of the Hall element is fixed by using a member (potential barrier part or element isolation part) that constitutes a part of the Hall element. However, the present invention is not limited to such a structure. For example, one or a plurality of conductive layers are positively provided separately from the constituent elements of the Hall element, that is, in order to fix the potential of the semiconductor substrate. May be fixed at an arbitrary potential.

Regarding the first embodiment of the vertical Hall element according to the present invention, (a) is a plan view schematically showing the planar structure of the Hall element, and (b) is taken along line L1-L1 in (a). Sectional drawing, (c) is sectional drawing which expands and shows the area | region A in (b). Regarding the second embodiment of the vertical Hall element according to the present invention, (a) is a plan view schematically showing the planar structure of the Hall element, and (b) is along the line L1-L1 in (a). Sectional drawing, (c) is sectional drawing which expands and shows the area | region A in (b). Regarding the third embodiment of the vertical Hall element according to the present invention, (a) is a plan view schematically showing the planar structure of the Hall element, and (b) is along the line L1-L1 in (a). Sectional drawing, (c) is sectional drawing which expands and shows the area | region A in (b). Regarding the third embodiment of the vertical Hall element according to the present invention, (a) is a plan view schematically showing the planar structure of the Hall element, and (b) is along the line L1-L1 in (a). Sectional drawing. Regarding the fifth embodiment of the vertical Hall element according to the present invention, (a) is a plan view schematically showing the planar structure of the Hall element, and (b) is taken along line L1-L1 in (a). Sectional drawing, (c) is sectional drawing which expands and shows the area | region A in (b). Regarding the sixth embodiment of the vertical Hall element according to the present invention, (a) is a plan view schematically showing the planar structure of the Hall element, and (b) is taken along line L1-L1 in (a). Sectional drawing. Sectional drawing which shows typically the cross-section of the Hall element about the modification of the vertical Hall element concerning the said 1st Embodiment. Sectional drawing which shows typically the cross-section of the Hall element about the modification of the vertical Hall element concerning the said 1st Embodiment. Sectional drawing which shows typically the cross-section of the Hall element about the modification of the vertical Hall element concerning the said 5th Embodiment. Sectional drawing which shows typically the cross-section of the Hall element about the modification of the vertical Hall element concerning the said 6th Embodiment. (A) is a top view which shows typically the planar structure of the Hall element about an example of the conventional Hall element (horizontal type Hall element), (b) is sectional drawing along the L1-L1 line of (a). (A) is a top view which shows typically the planar structure of the Hall element about an example of the conventional Hall element (vertical Hall element), (b) is sectional drawing along the L1-L1 line of (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 ... Semiconductor layer, BL1 ... Embedded layer, 12, 12a ... Semiconductor region, 13a-13e ... N ⁺ diffusion layer, 14, 14a, 14b ... Diffusion layer, BL1 ... Embedded layer, CT, CTa ... Conductive film material DF11, DF12 ... diffusion layer, GP1 ... conductor plate, HP1 ... magnetic detection part (hole plate), IL1, IL1a ... insulating film, T1, T1a ... trench.

Claims (9)

A current including a component perpendicular to the surface of the semiconductor substrate is supplied to a magnetic detection unit in the semiconductor substrate, and a magnetic field component horizontal to the surface of the semiconductor substrate is detected through a Hall voltage generated for the current. In vertical Hall element,
The semiconductor substrate has one or a plurality of conductive layers therein and is fixed to an arbitrary potential via a wiring that forms a contact with the conductive layer;
The vertical Hall element, wherein the conductive layer is a conductive film material embedded through an insulating film in a trench formed in the semiconductor substrate. The vertical Hall element according to claim 1, wherein the conductive film material is made of polycrystalline silicon to which a conductive impurity is added. A current including a component perpendicular to the surface of the semiconductor substrate is supplied to a magnetic detection unit in the semiconductor substrate, and a magnetic field component horizontal to the surface of the semiconductor substrate is detected through a Hall voltage generated for the current. In vertical Hall element,
The semiconductor substrate has one or a plurality of conductive layers therein and is fixed to an arbitrary potential via a wiring that forms a contact with the conductive layer;
The conductive layer comprises a diffusion layer formed in the form of a conductive impurity added to the semiconductor substrate,
A vertical Hall element characterized in that at least one pair of P-type and N-type diffusion layers as the conductive layer is arranged adjacent to the outer periphery of the Hall element. The vertical Hall element according to claim 1, wherein the semiconductor substrate is fixed to one of a power supply potential and a ground potential via a wiring that forms a contact with the conductive layer. The vertical Hall element according to any one of claims 1 to 4, wherein the conductive layer is a potential barrier section that partitions and forms the magnetic detection section in the semiconductor substrate. The vertical Hall element according to any one of claims 1 to 4, wherein the conductive layer is an element isolation portion that isolates the Hall element from other elements. The vertical Hall element according to any one of claims 1 to 6, wherein a conductor plate fixed at an arbitrary potential is disposed on the semiconductor substrate so as to cover at least the magnetic detection unit. The vertical Hall element according to claim 7, wherein the conductor plate is fixed to one of a power supply potential and a ground potential. The semiconductor substrate has a semiconductor region formed by adding a conductivity type impurity to the substrate, and the magnetic detection unit is formed in the semiconductor region. The vertical Hall element according to one item.

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