JP2006108528A - Vertical hall element and method for manufacturing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a vertical Hall element whose sensitivity as a magnetic detection element is to be increased, by increasing the Hall voltage to be generated with respect to the strength of the magnetic field(magnetism) applied to a magnetic detector electrically partitioned into a semiconductor substrate, and to provide a method for manufacturing the vertical Hall element. <P>SOLUTION: Separation walls(diffusion layers 14a and 14b), electrically separating a predetermined region that is a magnetic detector HP in a semiconductor substrate, are formed in configurations such that the magnetic detector HP can be made successively narrower from a substrate surface in a direction toward the inside. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention has a separation wall that electrically partitions a predetermined region to be a magnetic detection portion in a semiconductor substrate, and when a magnetic field component parallel to the substrate surface (chip surface) is applied to the magnetic detection portion, The present invention relates to a vertical Hall element that generates a Hall voltage corresponding to a magnetic field component and a method for manufacturing the same.

  As is well known, since the Hall element can detect the angle without contact, it is mounted on a so-called Hall IC or the like and used as an angle detection sensor such as a throttle valve opening sensor of an in-vehicle internal combustion engine as a magnetic sensor, for example. It is done. Currently, most of the Hall elements in practical use are horizontal Hall elements that detect a magnetic field component perpendicular to the substrate surface (chip surface). In recent years, however, in addition to this, Vertical Hall elements that detect magnetic field components have also been studied. Since the vertical Hall element has the feature that two elements that detect different phases (angles) can be integrated on one chip, the two vertical Hall elements are arranged at an angle of “90 °”. Thus, a rotation sensor or the like that can obtain a linear output (voltage signal) in an angle range of “0 ° to 360 °” can be realized. Conventionally, such vertical Hall elements include those described in Non-Patent Document 1, for example. Hereinafter, an outline of the vertical Hall element will be described with reference to FIG. FIG. 10A is a plan view of the Hall element, and FIG. 10B is a cross-sectional view taken along the line A-A ′ of FIG.

As shown in FIGS. 10A and 10B, the Hall element is roughly composed of a semiconductor layer (P ⁻ sub) 21 made of, for example, P-type silicon, and an N-type conductive impurity on the surface thereof. And a semiconductor region 22 made of, for example, N-type silicon formed by epitaxial growth on the buried layer BL. The buried layer BL functions as a lower electrode, and its impurity concentration is set higher than that of the semiconductor region 22.

  In this Hall element, the semiconductor region 22 has, for example, a P-type diffusion layer (P-type diffusion isolation wall) 24 connected to the semiconductor layer 21 so as to isolate the Hall element from other elements. Is formed. Further, contact regions 23a to 23e are formed on the surface of the semiconductor region 22 in such a manner that the impurity concentration (N-type) on the surface is selectively increased, and the contact regions 23a to 23e and the contact regions 23a to 23e are arranged there. A good ohmic contact is formed between the electrodes (wiring). The contact region 23a is connected to the power supply P through the electrodes (wirings) that form the ohmic contact, and is fixed at the power supply potential, the contact regions 23b and 23c are fixed at the ground potential, and the contact regions 23d and 23e. Are electrically connected to Hall voltage detection terminals V1 and V2, respectively.

  Further, as shown in FIG. 10A, in the region (active region) surrounded by the diffusion layer 24, the semiconductor region 22 is separated from the P type diffusion layer (through the pn junction isolation by each diffusion layer). P-type diffusion separation walls) 24a and 24b are divided into regions 22a to 22c that are separated from each other. Here, the diffusion layers 24a and 24b extend in a direction perpendicular to the substrate surface. In general, the widths of the diffusion layers 24a and 24b gradually decrease from the substrate surface toward the inside through the formation process of the diffusion layers. Further, as shown in FIG. 10B, the regions 22a to 22c form regions (spaces) that are electrically partitioned by the diffusion layers 24a and 24b even inside the substrate. Of these regions, the contact region 23b is formed in the region 22a, the contact region 23c is formed in the region 22b, and the contact regions 23a, 23d, and 23e are formed in the region (element region) 22c. Here, the contact regions 23a to 23e are arranged such that the contact region 23a is sandwiched between both the contact regions 23b and 23c and the contact regions 23d and 23e orthogonal to them. That is, the contact region 23a is disposed in such a manner as to face the contact regions 23b and 23c with the diffusion layers 24a and 24b interposed therebetween.

  In this Hall element, a region (space) that is electrically partitioned inside the substrate of the region 22c and that is sandwiched between the contact regions 23d and 23e is a so-called magnetic detector (hole). Plate) HP. That is, in this Hall element, a Hall voltage corresponding to the magnetic field applied here is generated.

In this Hall element, a constant drive current is supplied to the magnetic detection unit HP in the substrate by the power supply P shown in FIG. At this time, as indicated by an arrow in FIG. 10B, the current flows from the contact region 23a formed on the substrate surface through the magnetic detection unit HP to the buried layer BL and the contact regions 23b and 23c. Will flow to each. That is, this drive current is a current mainly including a component perpendicular to the substrate surface (chip surface) at least in the magnetic detection unit HP. Therefore, when a magnetic field including a component parallel to the substrate surface (chip surface) is applied to the magnetic detection unit HP in a state where this driving current is supplied, a known Hall effect causes a gap between the terminal V1 and the terminal V2. A Hall voltage corresponding to the magnetic field is generated. Therefore, by detecting the generated Hall voltage through the terminals V1 and V2, the magnetic field component to be detected based on the well-known relational expression “V _H = (R _H IB / d) cos θ”, that is, the Hall element Therefore, a magnetic field component parallel to the surface (chip surface) of the substrate used in the above is required. In the above relational expression, V _H is the Hall voltage, R _H is the Hall coefficient, I is the drive current, B is the magnetic flux density, d is the thickness of the magnetic detector (Hall plate), θ is the Hall element and the magnetic field. Each angle is shown. Further, in this Hall element, the width dimension d of the region (element region) 22c shown in FIG. 10A corresponds to the thickness (“d” in the above relational expression) of the magnetic detection part (Hall plate). . In addition, the direction in which the drive current flows in the Hall element is arbitrary, and the magnetic field (magnetism) can be detected by reversing the direction of the drive current.

Conventionally, as this type of vertical Hall element, as shown in FIG. 11, for example, instead of the diffusion layers (P-type diffusion separation walls) 24a and 24b, trenches T34a and T34b are used as separation walls. An insulating film 34a and 34b embedded in the semiconductor has been proposed. These insulating films 34a and 34b are also extended in a direction perpendicular to the substrate surface.
Ichisuke Maenaka, 3 others, “Characteristics and sensitivity enhancement of vertical Hall element”, IEEJ Transactions E, 1997, Vol. 117, No. 7, p. 364-370

  Thus, according to the vertical Hall element exemplified in FIG. 10, it is certain that the magnetic field component applied to the magnetic detection unit HP, more precisely, the magnetic field component parallel to the substrate surface (chip surface) is detected. Will be possible. However, even in this vertical Hall element, the sensitivity at the time of detecting a magnetic field (magnetism) is still not sufficient, and there remains room for improvement.

That is, when a drive current is supplied from the contact region 23a provided on the substrate surface to the magnetic detection unit HP, the current in the magnetic detection unit HP is lateral (in a direction parallel to the substrate surface) toward the inside of the substrate. Diffusion to the surface increases and current density decreases accordingly. As the current density decreases, the Hall voltage generated with respect to the intensity of the magnetic field (magnetism) applied to the magnetic detection unit HP decreases, and as a result, the sensitivity as a magnetic detection element decreases. Further, as can be seen from the relational expression “V _H = (R _H IB / d) cos θ”, in order to increase the sensitivity of the Hall element, the thickness of the magnetic detection unit (Hall plate) HP, that is, FIG. The width dimension d of the region (element region) 22c shown in 10 (a) may be reduced (narrowed). However, since it is necessary to secure a space for forming the contact region 23a in the region 22c, there is a limit to reducing the width dimension d. Also, if the width dimension d is reduced, the potential distribution inside the device due to the positional deviation when the positional deviation (alignment deviation) of the contact region 23a due to a mask alignment error or the like occurs in the manufacturing process (lithography process). As a result, a large unbalance (unbalance) occurs in the potential distribution inside the device. As a result, the Hall voltage (output voltage), that is, the so-called offset voltage (unbalanced voltage) generated even when no magnetic field is applied is increased, and accurate magnetic field detection is prevented.

  The same problem occurs in the vertical Hall element shown in FIG. In addition, since this Hall element employs trench isolation, crystal defects are likely to occur on the inner wall of the trench due to, for example, etching during formation, and carriers of drive current are trapped there. There is also a concern that the sensitivity is lowered. Such carrier traps occur more frequently as the width dimension d becomes smaller (narrower). Therefore, when the width dimension d is reduced, the above-described effect of increasing the sensitivity is reduced. However, the separation walls (insulating films 34a and 34b) in the Hall element are formed so as to be buried in the trenches T34a and T34b, and have a certain width from the substrate surface to the inside. Therefore, the diffusion of the drive current in the lateral direction (direction parallel to the substrate surface) is somewhat suppressed as compared with the previous vertical Hall element shown in FIG.

Note that the above situation is generally common when the Hall voltage is detected with the direction of the drive current reversed.
The present invention has been made in view of such circumstances, and increases the Hall voltage generated with respect to the strength of the magnetic field (magnetism) applied to the magnetic detection unit electrically partitioned in the semiconductor substrate, thereby increasing the magnetic field. It is an object of the present invention to provide a vertical Hall element that can increase sensitivity as a detection element and a method for manufacturing the same.

  In order to achieve such an object, according to the first aspect of the present invention, the semiconductor substrate includes a separation wall that electrically partitions a predetermined region to be a magnetic detection portion, and includes a component perpendicular to the surface of the semiconductor substrate. As a vertical Hall element that generates a Hall voltage corresponding to the magnetic field component when a magnetic field component parallel to the surface of the substrate is applied to the magnetic detection unit in a state where current is supplied to the magnetic detection unit, The separation wall is formed in such a manner that a predetermined region to be the magnetic detection portion is sequentially narrowed from the surface of the semiconductor substrate toward the inside.

  As described above, in the conventional vertical Hall element, when the drive current flows through the magnetic detection unit from the substrate surface to the inside, the current flows in the lateral direction (direction parallel to the substrate surface) toward the inside of the substrate. Increased diffusion to This has led to a decrease in the current density of the same current, and thus a decrease in sensitivity as a magnetic detection element. In this regard, according to the above structure, the magnetic detection section that is electrically partitioned by the separation wall and serves as a current path for the drive current is sequentially narrowed from the substrate surface toward the inside. For this reason, when the drive current flows through the magnetic detection section from the substrate surface to the inside, the current increases in the lateral direction corresponding to the diffusion amount that increases as it advances into the substrate. Diffusion is suppressed. Further, by suppressing the diffusion in the lateral direction in this way, the current density of the current flowing therethrough is also increased, and as a result, it is generated with respect to the intensity of the magnetic field (magnetism) applied to the magnetic detection unit. The Hall voltage will increase. That is, according to such a vertical Hall element, the sensitivity as a magnetic detection element is increased, and a magnetic field can be detected with high sensitivity. Note that the same effect can be obtained when the direction of the current is reversed, that is, when the drive current flows from the inside of the substrate toward the surface of the magnetic detection unit.

Further, as the separation wall, for example, as described in claim 2,
・ Those with a trapezoidal cross section.
Or as claimed in claim 3,
-A flat plate arranged in a V shape.
It is particularly effective to employ one having a shape such as. By adopting such a shape, the above-described structure in which the magnetic detection unit is sequentially narrowed from the substrate surface to the inside can be suitably realized. In addition, regarding the separation wall having the trapezoidal cross section, it is sufficient to form a trapezoidal shape having an inclination on at least the side on the magnetic detection unit side.

Moreover, regarding the vertical Hall element according to any one of claims 1 to 3, as the separation wall, for example, as described in claim 4,
A semiconductor device comprising a diffusion layer formed by adding conductive impurities to the semiconductor substrate.
Or as claimed in claim 5,
-Made of insulating film.
It is more effective to employ a separating wall. By adopting such a separation wall, a potential barrier is suitably formed through a pn junction (for example, in the case of a diffusion layer), and the magnetic detection unit is more reliably and suitable in a semiconductor substrate. It will be divided into two.

Further, as a method of manufacturing such a vertical Hall element, for example, according to the invention of claim 6,
After etching away a predetermined region to be a magnetic detection portion in the semiconductor substrate to form a trench with an inverted trapezoidal cross section having an inclined side wall, and forming a diffusion layer as the separation wall on the side wall of the trench A method of forming the separation wall in such a manner that a predetermined region to be the magnetic detection portion is sequentially narrowed from the surface of the semiconductor substrate toward the inside by burying a semiconductor film in the trench again.
Or, according to the invention of claim 7,
-A predetermined region to be a magnetic detection portion in the semiconductor substrate is removed by etching to form an inverted trapezoidal trench having an inclined side wall, and an insulating film as the separation wall is formed on the side wall of the trench Thereafter, the isolation wall is formed in such a manner that a predetermined region to be the magnetic detection portion is sequentially narrowed from the surface of the semiconductor substrate toward the inside by burying a semiconductor film in the trench again.
Alternatively, as in the invention according to claim 8,
-By performing ion implantation in an oblique direction on the semiconductor substrate and forming a diffusion layer as the separation wall therein, a predetermined region that becomes the magnetic detection portion is sequentially narrowed from the surface of the semiconductor substrate to the inside. A method of forming the separation wall in an aspect.
Alternatively, as in the invention according to claim 9,
In a mode in which the semiconductor substrate is etched away in an oblique direction and an insulating film serving as the separation wall is embedded therein, thereby sequentially narrowing a predetermined region serving as the magnetic detection unit from the surface of the semiconductor substrate to the inside. A method of forming the separation wall.
It is effective to adopt such a method. According to these manufacturing methods, the above structure is suitably realized. The manufacturing methods according to the sixth to ninth aspects are particularly effective when employed to realize the structure according to the third aspect.

(First embodiment)
A first embodiment of a vertical Hall element and a method for manufacturing the same according to the present invention will be described below.

  First, with reference to FIG. 1, the schematic structure and operation mode of the vertical Hall element according to this embodiment will be described. In FIG. 1, FIG. 1 (a) is a plan view schematically showing the planar structure of the Hall element, FIG. 1 (b) is a cross-sectional view taken along the line BB ′ of FIG. 1 (a), FIG.1 (c) is sectional drawing along the AA 'line of Fig.1 (a).

As shown in FIGS. 1 (a) to 1 (c), this Hall element is also roughly composed of a semiconductor layer (P ^- sub) 11 made of, for example, P-type silicon and an N-type conductive impurity on the surface thereof. And a semiconductor region 12 made of, for example, N-type silicon formed by epitaxial growth on the buried layer BL. The buried layer BL functions as a lower electrode, and the impurity concentration is set higher than that of the semiconductor region 12. In general, a semiconductor material such as silicon has a larger carrier mobility in a semiconductor made of N-type than in a semiconductor made of P-type. Therefore, the semiconductor region 12 is made of an N-type semiconductor material (for example, silicon). It is desirable to use However, a P-type semiconductor material (P ⁻ layer) can also be employed depending on the manufacturing process and structural conditions. Further, as the impurity concentration of the semiconductor region 12 is reduced (thinner), the carrier mobility in the same region is increased. Therefore, in order to increase the sensitivity as the Hall element, that is, to obtain a large voltage as the output voltage, the semiconductor region 12 It is more desirable to make the impurity concentration of 12 small (thin).

  In the semiconductor region 12, for example, a P-type diffusion layer (P-type diffusion separation wall) 14 is formed so as to be connected to the semiconductor layer 11 in order to isolate the Hall element from other elements. . Further, contact regions 13a to 13e are formed on the surface of the semiconductor region 12 in such a manner that the impurity concentration (N-type) on the surface is selectively increased, and the contact regions 13a to 13e and the contact regions 13a to 13e are arranged there. A good ohmic contact is formed between the electrodes (wiring). The contact region 13a is connected to the power source P through the electrodes (wirings) forming the ohmic contact, and is fixed at the power source (force) potential. The contact regions 13b and 13c are fixed at the ground potential. 13d and 13e are electrically connected to Hall voltage detection (sense) terminals V1 and V2, respectively.

  Further, as shown in FIG. 1A, in the region (active region) surrounded by the diffusion layer 14, the semiconductor region 12 is separated into a P-type diffusion layer (through a pn junction isolation by each diffusion layer). P-type diffusion separation walls) 14a and 14b are divided into regions 12a to 12c that are separated from each other. In addition, as shown in FIGS. 1B and 1C, the regions 12a to 12c form regions (spaces) that are electrically partitioned by the diffusion layers 14a and 14b even inside the substrate. . Of these regions, the contact region 13b is formed in the region 12a, the contact region 13c is formed in the region 12b, and the contact regions 13a, 13d, and 13e are formed in the region (element region) 12c. Here, the contact regions 13a to 13e are arranged in such a manner that the contact region 13a is sandwiched between both the contact regions 13b and 13c and the contact regions 13d and 13e orthogonal thereto. That is, the contact region 13a is disposed in such a manner as to face the contact regions 13b and 13c with the diffusion layers 14a and 14b interposed therebetween.

  In this Hall element, a region (space) that is electrically partitioned inside the substrate of the region 12c and that is sandwiched between the contact regions 13d and 13e is a so-called magnetic detector (hole). Plate) HP. That is, in this Hall element, a Hall voltage corresponding to the magnetic field applied here is generated. Here, the contact regions 13a to 13c for supplying a current to the magnetic detection unit HP are provided symmetrically with respect to the contact regions 13d and 13e that are portions for outputting the Hall voltage. Thereby, the Hall voltage generated with respect to the lateral current (current component flowing parallel to the substrate surface) is canceled, and the magnetic field component to be detected (magnetic field component parallel to the substrate surface) can be detected with high accuracy. become.

  Further, as shown in FIG. 1 (c), in this vertical Hall element, the diffusion layers 14a and 14b have a trapezoidal cross section and become the magnetic detection unit HP from the substrate surface to the inside. It is formed in such a manner that the (space) is narrowed sequentially.

FIG. 2 shows an operation mode of this vertical Hall element. That is, in this Hall element, a constant drive current is supplied to the magnetic detection unit HP in the substrate by the power source P shown in FIG. At this time, as indicated by an arrow in FIG. 2A, the current flows from the contact region 13a formed on the substrate surface through the magnetic detection unit HP to the buried layer BL and the contact regions 13b and 13c. Will flow to each. That is, the drive current is a current mainly including a component perpendicular to the substrate surface (chip surface) at least in the magnetic detection unit HP. Therefore, when a magnetic field including a component parallel to the substrate surface (chip surface) is applied to the magnetic detection unit HP in a state where this driving current is supplied, a known Hall effect causes a gap between the terminal V1 and the terminal V2. A Hall voltage corresponding to the magnetic field is generated. Therefore, by detecting the generated Hall voltage through the terminals V1 and V2, the magnetic field component to be detected based on the well-known relational expression “V _H = (R _H IB / d) cos θ”, that is, the Hall element Therefore, a magnetic field component parallel to the surface (chip surface) of the substrate used in the above is required. In the above relational expression, V _H is the Hall voltage, R _H is the Hall coefficient, I is the drive current, B is the magnetic flux density, d is the thickness of the magnetic detector (Hall plate), θ is the Hall element and the magnetic field. Each angle is shown. Further, in this Hall element, the width dimension d of the region (element region) 12c shown in FIG. 1A corresponds to the thickness (“d” in the above relational expression) of the magnetic detection portion (Hall plate). .

  Further, the direction in which the drive current flows in this Hall element is arbitrary, and as shown in FIG. 2B, the contact region 13a is fixed at the ground potential, and the contact regions 13b and 13c are fixed at the power supply potential. It is also possible to detect the magnetic field (magnetism) by reversing the direction of the current. In this case, the potential around the magnetic detection unit HP is fixed and stabilized, and the magnetic detection accuracy is further improved.

  Incidentally, as described above, in the conventional vertical Hall element (see FIGS. 9 and 10), when the drive current flows from the substrate surface to the inside through the magnetic detection unit HP, Diffusion in the lateral direction (direction parallel to the substrate surface) increases. This has led to a decrease in the current density of the same current, and thus a decrease in sensitivity as a magnetic detection element. In this regard, according to the above structure, the inside of the substrate is electrically partitioned by the diffusion layers 14a and 14b, and the magnetic detection unit HP that becomes a current path of the drive current is sequentially narrowed from the substrate surface toward the inside. . For this reason, when the drive current flows through the magnetic detection unit HP from the substrate surface to the inside, the lateral direction of the current increases as the current advances toward the inside of the substrate corresponding to the diffusion amount that increases accordingly. Diffusion into the body is suppressed. Further, by suppressing the diffusion in the lateral direction in this way, the current density of the current flowing therethrough is also increased, and as a result, it is generated with respect to the intensity of the magnetic field (magnetism) applied to the magnetic detection unit. The Hall voltage will increase. That is, according to such a vertical Hall element, the sensitivity as a magnetic detection element is increased, and a magnetic field can be detected with high sensitivity. Note that the same effect can be obtained when the direction of the current is reversed, that is, when the drive current flows through the magnetic detection unit HP from the inside of the substrate toward the surface.

  Next, a method for manufacturing the vertical Hall element according to this embodiment will be described. Here, a method of forming the separation wall in the semiconductor substrate, that is, the diffusion layers 14a and 14b will be mainly described.

  That is, when forming the separation wall, first, for example, boron (boron) or the like is formed at a desired portion of the semiconductor substrate by, for example, ion implantation or thermal diffusion using an appropriate mask patterned by photolithography, for example. Add P-type impurities. Thereafter, this is subjected to an appropriate heat treatment to diffuse the added P-type impurity into a desired pattern (shape), that is, a trapezoidal cross section as shown in FIG. Thus, the diffusion layers 14a and 14b are formed in such a manner that the magnetic detection part HP is successively narrowed from the substrate surface toward the inside.

As described above, according to the vertical Hall element according to this embodiment, the following excellent effects can be obtained.
(1) With respect to the separation walls (diffusion layers 14a and 14b) that electrically partition a predetermined region to be the magnetic detection unit HP in the semiconductor substrate, the magnetic detection unit HP is sequentially narrowed from the substrate surface toward the inside. It was made to form in an aspect. As a result, the Hall voltage generated with respect to the intensity of the magnetic field (magnetism) applied to the magnetic detection unit HP electrically partitioned in the semiconductor substrate can be increased, and the sensitivity as the magnetic detection element can be increased. become.

  (2) Further, increasing the sensitivity as a magnetic detection element in this way leads to an improvement in the yield of the Hall element and a reduction in cost, leading to energy saving.

  (3) As described above, increasing the sensitivity as the magnetic detection element is also effective in securing a sufficient width as the width dimension d (FIG. 1A) of the region (element region) 12c. As described above, the offset voltage (unbalanced voltage) can be reduced by securing a sufficient width as the width dimension d. That is, the vertical Hall element according to this embodiment is also effective in reducing the offset voltage (unbalanced voltage).

  (4) As the separation wall, a wall having a trapezoidal cross section as shown in FIG. By adopting such a shape, the above-described structure in which the magnetic detection unit HP is sequentially narrowed from the substrate surface toward the inside is also suitably realized.

  (5) Further, the separation wall is made of a diffusion layer formed by adding a conductive impurity to the semiconductor substrate. By adopting such a separation wall, a potential barrier is suitably formed there through a pn junction formed inside the substrate, and the magnetic detection unit HP is more reliably and suitably formed in the semiconductor substrate. Will be.

(Second Embodiment)
3 and 4 show a second embodiment of the vertical Hall element and the manufacturing method thereof according to the present invention.

  Hereinafter, with reference to these FIG. 3 and FIG. 4, the schematic structure of the vertical Hall element according to this embodiment and its operation mode will be described focusing on the differences from the first embodiment. 3 and 4 correspond to the previous FIG. 1 and FIG. 2, respectively, and the same elements as those shown in FIG. 1 and FIG. I will not repeat the explanation of these elements.

  As shown in FIG. 3, this vertical Hall element also basically has a structure according to the vertical Hall element of the first embodiment exemplified in FIG. However, the vertical Hall element has a structure in which the region 12b, the contact region 13c (see FIG. 1), and the like are omitted. Therefore, the area of about “1/3” is reduced as compared with the vertical Hall element shown in FIG. 1, and the size can be greatly reduced. Here, for the convenience of element design, the diffusion layers (separation walls) 14a and 14b having a trapezoidal cross section are formed in a trapezoidal shape inclined only on the magnetic detection unit HP side.

  The operation mode of this vertical Hall element is basically the same as that of the previous vertical Hall element illustrated in FIG. That is, for example, as shown in FIG. 4A, the contact region 13a is fixed to the power supply (force) potential and the contact region 13b is fixed to the ground potential, as shown by the arrows in FIG. 4A. The magnetic field (magnetism) applied to the magnetic detection unit HP can be detected by causing the drive current to flow from the substrate surface toward the inside of the magnetic detection unit HP. Further, as shown in FIG. 4B, the contact region 13a is fixed at the ground potential and the contact region 13b is fixed at the power supply potential, thereby detecting the magnetic field (magnetism) with the direction of the drive current reversed. You can also. In this case, the magnetic detection accuracy is further improved as described above.

  As described above, according to the vertical Hall element according to this embodiment, in addition to the same effects as the effects (1) to (5) of the previous first embodiment or the effects equivalent thereto. Further, the following effects can be obtained.

  (6) The region 12b, the contact region 13c (see FIG. 1), etc. are omitted. As a result, the area of about “1/3” is reduced as compared with the vertical Hall element shown in FIG. 1, and the size can be significantly reduced.

(Third embodiment)
5 and 6 show a third embodiment of the vertical Hall element and the method for manufacturing the same according to the present invention.

  First, with reference to these FIG. 5 and FIG. 6, the schematic structure and operation mode of the vertical Hall element according to this embodiment will be described focusing on the differences from the first embodiment. 5 and FIG. 6 correspond to FIG. 1 and FIG. 2, respectively, and the same elements as those shown in FIG. 1 and FIG. I will not repeat the explanation of these elements.

  As shown in FIG. 5, this vertical Hall element also basically has the same structure as the vertical Hall element of the first embodiment illustrated in FIG. However, in this vertical Hall element, instead of the diffusion layers 14a and 14b, insulating films 15a and 15b made of, for example, silicon oxide are used as separation walls. And this separation wall is formed in the flat plate shape arrange | positioned by V shape, The magnetic detection part HP is electrically partitioned and formed in the inside of a board | substrate.

  The operation mode of this vertical Hall element is basically the same as that of the previous vertical Hall element illustrated in FIG. That is, for example, as shown in FIG. 6A, the contact region 13a is fixed to the power supply (force) potential and the contact region 13b is fixed to the ground potential, as shown by the arrows in FIG. 6A. The magnetic field (magnetism) applied to the magnetic detection unit HP can be detected by causing the drive current to flow from the substrate surface toward the inside of the magnetic detection unit HP. Further, as shown in FIG. 6B, the contact region 13a is fixed at the ground potential and the contact region 13b is fixed at the power supply potential, thereby detecting the magnetic field (magnetism) with the direction of the drive current reversed. You can also. In this case, the magnetic detection accuracy is further improved as described above.

  Next, a method for manufacturing the vertical Hall element according to this embodiment will be described. Here, a method for forming the separation wall in the semiconductor substrate, that is, the insulating films 15a and 15b will be mainly described.

  That is, in forming this separation wall, first, a predetermined region to be the magnetic detection part HP in the semiconductor substrate is removed by etching to form a trench having an inverted trapezoidal cross section having an inclined side wall. Then, after the insulating films 15a and 15b are formed on the sidewall of the trench by, for example, thermal oxidation or CVD (chemical vapor deposition), the semiconductor film E12 made of, for example, silicon is buried in the trench again by, for example, epitaxial growth. Thus, the insulating films 15a and 15b are formed in such a manner that the magnetic detection part HP is successively narrowed from the substrate surface toward the inside.

  As described above, according to the vertical Hall element and the method of manufacturing the same according to this embodiment, the same effects as the effects (1) to (5) according to the first embodiment described above or equivalent thereto. In addition to the above effects, the following effects can be obtained.

  (7) In forming the separation wall, a predetermined region to be the magnetic detection part HP in the semiconductor substrate is removed by etching to form an inverted trapezoidal trench having an inclined side wall and insulated on the side wall of the trench. After the films 15a and 15b were formed, the semiconductor film E12 was buried again in the trench. By adopting such a manufacturing method, it is possible to suitably form a separation wall that sequentially narrows the magnetic detection unit HP from the substrate surface toward the inside.

(Fourth embodiment)
FIG. 7 shows a fourth embodiment of the vertical Hall element and the method for manufacturing the same according to the present invention.

  Hereinafter, the schematic structure of the vertical Hall element according to the present embodiment will be described with reference to FIG. 7, focusing on the differences from the first embodiment. FIGS. 7A to 7C correspond to the previous FIGS. 1A to 1C, respectively, and are the same as those shown in FIGS. 1A to 1C. Are denoted by the same reference numerals, and redundant description of these elements is omitted.

  As shown in FIG. 7, this vertical 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, in this vertical Hall element, an SOI having an embedded layer BL on an appropriate support substrate L1, and an insulating layer L2 made of, for example, silicon oxide or the like and the semiconductor region 12 are sequentially formed. A (Silicon On Insulator) substrate is used as a base material (substrate) instead of the epitaxial substrate including the embedded layer BL. Even with such a structure, the same effect as described above or an effect equivalent thereto can be obtained.

  Further, as shown in FIG. 8, when the SOI substrate is adopted for the vertical Hall element according to the third embodiment, the same effect as described above or an effect similar thereto can be obtained. It will be. Further, although not shown, the same applies to the case where the SOI substrate is adopted for the vertical Hall element of the second embodiment.

  As described above, according to the vertical Hall element according to this embodiment, the same effects as the effects (1) to (5) of the previous first embodiment or an effect equivalent thereto can be obtained. Be able to.

(Other embodiments)
In addition, each said embodiment can also be implemented with the following aspects.
In the vertical Hall element of the third embodiment, a P-type diffusion layer can be used as the separation wall instead of the insulating films 15a and 15b. In addition, as a method for manufacturing such a Hall element (more specifically, a method for forming a separation wall), the following method is adopted to conform to the effect (7) according to the third embodiment. You can get an effect. That is, when forming the separation wall, a predetermined region to be the magnetic detection part HP in the semiconductor substrate is removed by etching to form a trench having an inverted trapezoidal shape with an inclined side wall. Then, after the P-type diffusion layer is formed on the side wall of the trench by, for example, ion implantation or thermal diffusion, the semiconductor film E12 made of, for example, silicon is buried in the trench again by, for example, epitaxial growth. Thus, the separation wall (diffusion layer) is formed in such a manner that the magnetic detection part HP is successively narrowed from the substrate surface toward the inside. In addition,
(A) By performing ion implantation in an oblique direction on the semiconductor substrate and forming a P-type diffusion layer therein, the separation wall (diffusion layer) is formed in such a manner that the magnetic detection part HP is successively narrowed from the substrate surface toward the inside. ) Forming method.
(B) The above-described separation wall (insulation) is formed in such a manner that a predetermined region that becomes the magnetic detection part HP is narrowed sequentially from the substrate surface toward the inside by etching and removing the semiconductor substrate in an oblique direction and embedding an appropriate insulating film therein. Film).
By adopting such a method, a structure according to the above structure can be suitably realized.

  A structure in which a diffusion layer is provided on the inner wall portion of the trench formed in the vertical Hall element of the third embodiment can also be used. By adopting such a structure, for example, carrier recombination caused by damage generated in the inner wall of the trench in the formation process or the like is preferably suppressed, and as a result, high sensitivity as a magnetic detection element can be achieved.

  In each of the above embodiments, the diffusion layer (P-type diffusion separation wall) 14 is used for element isolation of the Hall element. However, the method of element isolation is not limited to this, and is arbitrary. For example, trench isolation can be employed instead of the diffusion layer. As an example, FIG. 9 shows a Hall element employing trench isolation for the vertical Hall element of the first embodiment, that is, an insulating film 16 buried in the trench T16. 9A to 9C correspond to the previous FIGS. 1A to 1C.

  In each of the above embodiments, an epitaxial substrate or an SOI substrate is adopted. However, any substrate can be used without being limited thereto. For example, a substrate made of a single conductivity type (for example, P type), a multiple diffusion layer substrate such as P type-N type-P type or N type-P type-N type, and the like can be appropriately employed. Further, the buried layer BL is not an essential configuration.

  Furthermore, in each of the above embodiments, the present invention is similarly applied to a Hall element having 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. can do.

  In each of the above embodiments, silicon is used as the material for the substrate, but other materials may be appropriately employed depending on the manufacturing process, structural conditions, and the like. For example, compound semiconductor materials such as GaAs, InSb, InAs, and SiC, and other semiconductor materials such as Ge (germanium) can also 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 structure using the epitaxial film as the semiconductor region 12 is illustrated, but a structure in which this is formed as a diffusion layer can also be used.
In the above embodiments, the contact regions 13a to 13e are provided in order to achieve ohmic contact with the wiring (electrode). However, this is not an essential configuration. For example, a wiring (electrode) may be provided directly on the semiconductor region 12 without providing such a contact region.

  In each of the above embodiments, constant current driving has been described as an example of a vertical Hall element driving method. However, this vertical Hall element driving method is arbitrary, for example, driven by constant voltage driving. You can also.

  In each of the above embodiments, diffusion having a flat plate-like shape arranged in a trapezoidal cross section or a V-shape as a separation wall that electrically divides a predetermined region to be a magnetic detection unit HP in a semiconductor substrate It was decided to use a layer or an insulating film. However, the separation wall is not limited to these, and it suffices that the separation wall is formed in such a manner that a predetermined region to be a magnetic detection portion is sequentially narrowed from the surface of the semiconductor substrate to the inside.

1A is a plan view schematically showing a schematic structure of a Hall element, and FIG. 2B is a cross-sectional view taken along line BB in FIG. Sectional view along line ', (c) is a sectional view along line AA' in (a). (A) And (b) is sectional drawing which illustrates the operation | movement aspect of the vertical Hall element which concerns on the 1st Embodiment. Regarding the second embodiment of the vertical Hall element and the method for manufacturing the same according to the present invention, (a) is a plan view schematically showing the schematic structure of the Hall element, and (b) is a BB of (a). Sectional view along line ', (c) is a sectional view along line AA' in (a). (A) And (b) is sectional drawing which illustrates the operation | movement aspect of the vertical Hall element based on the 2nd Embodiment. In the third embodiment of the vertical Hall element and the manufacturing method thereof according to the present invention, (a) is a plan view schematically showing the schematic structure of the Hall element, and (b) is BB of (a). Sectional view along line ', (c) is a sectional view along line AA' in (a). (A) And (b) is sectional drawing which illustrates the operation | movement aspect of the vertical Hall element based on the 3rd Embodiment. In the fourth embodiment of the vertical Hall element and the method for manufacturing the same according to the present invention, (a) is a plan view schematically showing the schematic structure of the Hall element, and (b) is a BB of (a). Sectional view along line ', (c) is a sectional view along line AA' in (a). (A) is a top view which shows the modification of the vertical Hall element based on the said 4th Embodiment, (b) is sectional drawing along the BB 'line of (a), (c) is (a) ) Is a cross-sectional view along the line AA ′. (A) is a top view which shows another modification of the vertical Hall element based on the said 4th Embodiment, (b) is sectional drawing along the BB 'line of (a), (c) is Sectional drawing along the AA 'line of (a). (A) is a top view which shows typically the planar structure of the Hall element about an example of the conventional vertical Hall element, (b) is sectional drawing along the A-A 'line of (a). Sectional drawing which shows another example of the conventional vertical Hall element.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Semiconductor layer, 12 ... Semiconductor region, 12a-12c ... Region, 13a-13e ... Contact region, 14, 14a, 14b ... Diffusion layer, 15a, 15b, 16 ... Insulating film, E12 ... Semiconductor film, HP ... Magnetic detection Department.

Claims (9)

A separation wall that electrically divides a predetermined region to be a magnetic detection unit in the semiconductor substrate, and a current including a component perpendicular to the surface of the semiconductor substrate is supplied to the magnetic detection unit; When a magnetic field component parallel to the surface is applied to the magnetic detection unit, in a vertical Hall element that generates a Hall voltage according to the magnetic field component,
The vertical Hall element, wherein the separation wall is formed in such a manner that a predetermined region to be the magnetic detection portion is sequentially narrowed from the surface of the semiconductor substrate toward the inside. The vertical Hall element according to claim 1, wherein the separation wall is formed with a trapezoidal cross section. The vertical Hall element according to claim 1, wherein the separation wall is formed in a flat plate shape arranged in a V shape. The vertical Hall element according to any one of claims 1 to 3, wherein the separation wall is formed of a diffusion layer formed by adding a conductive impurity to the semiconductor substrate. The vertical Hall element according to claim 1, wherein the separation wall is made of an insulating film. A separation wall that electrically divides a predetermined region to be a magnetic detection unit in the semiconductor substrate, and a current including a component perpendicular to the surface of the semiconductor substrate is supplied to the magnetic detection unit; When a magnetic field component parallel to the surface is applied to the magnetic detection unit, a method of manufacturing a vertical Hall element that generates a Hall voltage according to the magnetic field component,
A predetermined region to be a magnetic detection portion in the semiconductor substrate is removed by etching to form an inverted trapezoidal trench having an inclined side wall, and a diffusion layer as the separation wall is formed on the side wall of the trench. The isolation wall is formed in such a manner that a predetermined region serving as the magnetic detection portion is sequentially narrowed from the surface of the semiconductor substrate toward the inside by burying a semiconductor film in the trench again. Production method. A separation wall that electrically divides a predetermined region to be a magnetic detection unit in the semiconductor substrate, and a current including a component perpendicular to the surface of the semiconductor substrate is supplied to the magnetic detection unit; When a magnetic field component parallel to the surface is applied to the magnetic detection unit, a method of manufacturing a vertical Hall element that generates a Hall voltage according to the magnetic field component,
Etching and removing a predetermined region to be a magnetic detection part in the semiconductor substrate to form a trench having an inverted trapezoidal shape with an inclined side wall, and forming an insulating film as the separation wall on the side wall of the trench, A vertical Hall element characterized in that the isolation wall is formed in such a manner that a predetermined region serving as the magnetic detection portion is narrowed sequentially from the surface of the semiconductor substrate toward the inside by burying a semiconductor film in the trench again. Manufacturing method. A separation wall that electrically divides a predetermined region to be a magnetic detection unit in the semiconductor substrate, and a current including a component perpendicular to the surface of the semiconductor substrate is supplied to the magnetic detection unit; When a magnetic field component parallel to the surface is applied to the magnetic detection unit, a method of manufacturing a vertical Hall element that generates a Hall voltage according to the magnetic field component,
A mode in which a predetermined region to be the magnetic detection portion is sequentially narrowed from the surface of the semiconductor substrate to the inside by performing ion implantation in an oblique direction to the semiconductor substrate and forming a diffusion layer as the separation wall therein. A method of manufacturing a vertical Hall element, comprising: forming the separation wall. A separation wall that electrically divides a predetermined region to be a magnetic detection unit in the semiconductor substrate, and a current including a component perpendicular to the surface of the semiconductor substrate is supplied to the magnetic detection unit; When a magnetic field component parallel to the surface is applied to the magnetic detection unit, a method of manufacturing a vertical Hall element that generates a Hall voltage according to the magnetic field component,
The semiconductor substrate is etched away in an oblique direction, and an insulating film serving as the separation wall is embedded therein, whereby the predetermined region to be the magnetic detection portion is sequentially narrowed from the surface of the semiconductor substrate toward the inside. A method of manufacturing a vertical Hall element, comprising forming a separation wall.

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