JP2010263231A - Magnetic detector - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a magnetic detector which reduces sensitivity dispersion between products and improve long-term reliability without sacrificing sensitivity. <P>SOLUTION: In a p-type element forming region 3a on a portion of a p-type silicon layer 3 as a semiconductor layer, a p-type well region 8 and an n-type collector region 6 are formed separately from each other and an n-type emitter region 5 is formed on the surface side of the well region 8. A recombination region 7 is composed of an n-type impurity diffusion region acting as a recombination center of minority carriers in a base region 4. The recombination region is formed on the surface sides of the well region 8 and the base region 4 composed of a portion between the well region 8 and the collector region 6 of the element forming region 3a. An insulation film 12 is formed on the surface side of the p-type silicon layer 3. The recombination region 7 is formed of a polycrystalline semiconductor film with a different conduction type from that of the base region 4, so that a potential difference is formed between the recombination region 7 and the base region 4. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a magnetic detection device, and more particularly to a magnetic detection device that is used in an electronic compass or the like to detect geomagnetism.

  In recent years, with the increase in demand for portable GPS terminal devices that can acquire position information using GPS, the demand for electronic compass for detecting the orientation (azimuth) of GPS terminal devices is also increasing. is there. Such an electronic compass requires a small magnetic detection device capable of detecting geomagnetism regardless of the attitude of the GPS terminal device.

  As an example of this type of magnetic detection device, a magnetic transistor having the configuration shown in FIG. 12 has been proposed (see, for example, Non-Patent Document 1). The magnetic transistor having the structure shown in FIG. 12 is formed using an SOI substrate in which a p-type silicon layer 3 ′ is formed on an insulating layer 2 ′ made of a silicon oxide film on a support substrate 1 ′ made of a silicon substrate. .

In the above-described magnetic transistor, an n-type emitter region 5 ′ and an n-type collector region 6 ′ are formed in a p-type silicon layer 3 ′ so as to be separated from each other, and between the emitter region 5 ′ and the collector region 6 ′. A p-type base region 4 'is formed. Further, on the surface side of the base region 4 ′, a recombination region 7 ′ that is separated from the emitter region 5 ′ and the collector region 6 ′ and functions as a minority carrier recombination center in the base region 4 ′ is formed. Here, the recombination region 7 ′ is formed by introducing defects into a predetermined portion on the surface side of the base region 4 ′ by the reverse sputtering method, and the SiO ₂ film is formed on the recombination region 7 ′ by the sputtering method. (Not shown) is formed. The base region 4 ′ is connected to the base electrode 9 ′ (shown schematically in FIG. 12B) via the base contact region 114 ′ having a higher impurity concentration than the base region 4 ′, and the emitter region 5. 'Is connected to the emitter electrode 10' (schematically shown in FIG. 12 (b)), and the collector region 6 'is connected to the collector electrode 11' (schematically shown in FIG. 12 (b)). ing.

  Hereinafter, the operation of the above-described magnetic transistor will be described.

The basic operation of the magnetic transistor described above is the same as that of a known npn transistor. As shown in FIG. 12B, the collector electrode 11 ′ is placed between the collector electrode 11 ′ and the emitter electrode 10 ′ on the high potential side. applied with a composed DC voltage V _CE, by applying a DC voltage V _bE of the base electrode 9 'is a high potential side between' the emitter electrode 10 'base electrode 9 and the base region 4'emitter region Since the forward bias is applied between 5 ′, electrons are injected from the emitter region 5 ′ into the base region 4 ′, and the electrons injected into the base region 4 ′ become minority carriers and move through the base region 4 ′ by diffusion. Then, it reaches the end of a depletion layer (not shown) extending from the collector region 6 ′ to the base region 4 ′ side, and is absorbed by the collector region 6 ′ to become a collector current. An arrow A1 in FIG. 12B shows an example of the moving direction of the electron e ⁻ that reaches the end of the depletion layer among the electrons e ⁻ that are minority carriers in the base region 4 ′.

Here, when a magnetic field perpendicular to the direction of the current in the base region 4 ′ (the left direction in FIG. 12B) is applied in a state where the collector current flows through the magnetic transistor, the base region 4 ′. The moving direction of the electrons e ^{− in} the inside changes due to the Lorentz force by the magnetic field. For example, if 12 (b) the direction of the external magnetic field H1 shown in the upper part of the lower right (FIG. 12 the external magnetic field H1 of the paper in the normal direction of the (b)) is applied, electrons e ^- Fig. 12 (b Since the Lorentz force F1 is received in the upward direction, the moving direction of the electron e ⁻ is deflected toward the recombination region 7 ′ at an angle according to the strength of the magnetic field (magnetic flux density) (in FIG. 12B). The arrow A2 indicates an example of the moving direction of the electron e ⁻ that has received the Lorentz force F1 in the base region 4 ′). In short, in the above-described magnetic transistor, when the external magnetic field H1 is applied, the surface of the recombination region 7 ′ among the electrons e ⁻ injected into the base region 4 ′ is larger than when the external magnetic field H1 is not applied. The proportion of electrons e ⁻ that disappear due to recombination increases. As a result, the probability of arrival of electrons e ⁻ in the collector region 6 ′ decreases, and the current value of the collector current decreases.

On the other hand, when the external magnetic field H2 in the direction shown in the lower right lower part of FIG. 12B is applied to the magnetic transistor (that is, the external magnetic field H2 in the direction opposite to the external magnetic field H1), the base region 4 Since the electrons “e ^{− in”} are subjected to a Lorentz force in the downward direction in FIG. 11B, they are deflected in a direction approaching the insulating layer 2 ′. Therefore, compared with the case where the external magnetic field H1 is applied, the proportion of the electrons e ⁻ that disappear due to surface recombination in the recombination region 7 ′ among the electrons injected into the base region 4 ′ is reduced. The probability of arrival of the electrons e ^{− at} the collector region 6 ′ increases, and the current value of the collector current increases.

  In the above-described magnetic transistor, the current value of the collector current changes according to the direction and magnitude (magnetic flux density) of the external magnetic field. Therefore, the direction and strength of the external magnetic field are measured by measuring the collector current as the sensor current. Can be detected.

By the way, as a small magnetic detecting device, in addition to the above-described magnetic transistor, a magnetic diode in which a pin diode is formed on a silicon layer of an SOI substrate and a recombination region is formed on the surface side of the i layer has been proposed ( For example, see Patent Document 1). However, since this magnetic diode operates in the state where an electric field is applied in the carrier moving direction, it takes a short time for the external electric field to act on the carrier injected into the i layer and transported, and the sensitivity (magnetic sensitivity) is low. There was a problem. In contrast, in the magnetic transistor described above, electrons e are minority carriers injected into the base region 4 'is transported ^- the electric field is not applied to the moving direction of the electrons e ^- time the external magnetic field acts on The moving direction of the electron e ⁻ is easily deflected by the external magnetic field, and the sensitivity can be improved.

  In the magnetic diode described above, the recombination current also becomes the sensor current. In the magnetic transistor described above, the recombination current contributes to the increase in the emitter current, but directly affects the collector current that is the sensor current. Therefore, there is an advantage that the change of the sensor current with respect to the change of the external magnetic field can be increased and the sensitivity can be improved.

JP 2002-134758 A (see paragraphs [0016]-[0018] and FIG. 2)

Shin Takahashi, Mitsuteru Kimura, “Proposal of a new magnetic transistor with a recombination region in the base”, Physical Society of Japan, Physical Sensor Study Group, May 13, 2004, PHS-04-12

  By the way, in the magnetic transistor having the configuration shown in FIG. 12, the recombination speed in the recombination region 7 ′ affects the sensitivity, but a method of physically introducing defects in the recombination region 7 ′ by reverse sputtering is used. As a result, the process variation of the recombination speed in the recombination region 7 ′ was large (low reproducibility), and the sensitivity was large. In addition, since a part of the defects in the recombination region 7 ′ is recovered by the thermal process after reverse sputtering at the time of manufacture, and the state of the recombination region 7 ′ fluctuates, the recombination speed of the recombination region 7 ′ It was difficult to design. Further, in the above-described magnetic transistor, when used for a long period of time, the sensitivity changes due to the influence of ions entering the interface between the recombination region 7 'and the silicon oxide film on the recombination region 7' from the surrounding environment. There was a problem with long-term reliability.

  The present invention has been made in view of the above reasons, and an object thereof is to provide a magnetic detection device capable of reducing variation in sensitivity between products and improving long-term reliability without sacrificing sensitivity. is there.

  The magnetic detection device of the present invention includes a second conductivity type emitter region formed in a first conductivity type semiconductor layer on an insulating layer, and a second conductivity type formed in the semiconductor layer so as to be separated from the emitter region. A conductive type collector region; a first conductive type base region interposed between the emitter region and the collector region in the semiconductor layer; and a surface region of the emitter region. A connected emitter electrode; a base electrode formed on the surface side of the base region and electrically connected to the base region; and a collector formed on the surface side of the collector region and electrically connected to the collector region Minority carrier recombination in the base region formed on the surface side of the base region and the emitter region and the collector region, respectively. A recombination region serving as a center, and a voltage at which a pn junction between the collector region and the base region is reverse-biased is applied between the collector electrode and the emitter electrode. In a state in which a forward bias voltage is applied between the emitter electrode and the emitter electrode, the collector current is changed by changing the ratio of recombination in the recombination region among the minority carriers injected into the base region by an external magnetic field. In the magnetic detection device, the recombination region is formed of a polycrystalline semiconductor film formed on the base region and doped with impurities so as to have a potential difference from the base region, and is formed on the surface side of the semiconductor layer. An insulating film covering the entire surface of the recombination region is formed.

  In this magnetic detection device, it is preferable that the conductivity type of the recombination region is a second conductivity type.

  In this magnetic detection device, it is preferable that the conductivity type of the recombination region is the first conductivity type and the impurity concentration of the recombination region is higher than the impurity concentration of the base region.

  In the magnetic detection device of the present invention, there is an effect that sensitivity variation between products can be reduced and long-term reliability can be improved without sacrificing sensitivity.

Embodiment 1 is shown, (a) is a schematic plan view, and (b) is an X-X ′ sectional view of (a). It is a graph which shows the simulation result of a current-voltage characteristic same as the above. Embodiment 2 is shown, (a) is a schematic plan view, and (b) is an X-X ′ sectional view of (a). Embodiment 3 is shown, (a) is a schematic plan view, and (b) is an X-X ′ sectional view of (a). Embodiment 4 is shown, (a) is a schematic plan view, and (b) is an X-X ′ sectional view of (a). Embodiment 5 is shown, (a) is a schematic plan view, and (b) is an X-X ′ sectional view of (a). Embodiment 6 is shown, (a) is a schematic plan view, and (b) is an X-X ′ sectional view of (a). Embodiment 7 is shown, (a) is a schematic plan view, and (b) is an X-X ′ sectional view of (a). Embodiment 8 is shown, (a) is a schematic plan view, (b) is an X-X 'cross-sectional view of (a). Embodiment 9 is shown, (a) is a schematic plan view, and (b) is an X-X ′ sectional view of (a). A reference example is shown, (a) is a schematic plan view, and (b) is an X-X ′ cross-sectional view of (a). A prior art example is shown, (a) is a schematic plan view, and (b) is an X-X ′ cross-sectional view of (a).

  In the following embodiments, the first conductivity type is described as p-type, and the second conductivity type is described as n-type. However, the p-type and n-type may be interchanged.

(Embodiment 1)
Hereinafter, the magnetic detection device of the present embodiment will be described with reference to FIGS.

  In the magnetic detection device of this embodiment, a p-type silicon layer 3 is formed on an insulating layer 2 made of a silicon oxide film on a support substrate 1 made of a silicon substrate, similarly to the magnetic transistor having the configuration shown in FIG. The p-type silicon layer 3 is formed of an SOI substrate and constitutes a first conductivity type semiconductor layer.

The magnetic detection device of this embodiment includes an element isolation region 13 that reaches the insulating layer 2 from the surface of the p-type silicon layer 3 in the SOI substrate, and is surrounded by the insulating layer 2 and the element isolation region 13 in the p-type silicon layer 3. This region is an island-shaped element formation region (island semiconductor region) 3a. Therefore, the conductivity type of the element formation region 3a is p-type. The element isolation region 13 is composed of a SiO ₂ film embedded in an isolation groove 3b having a depth reaching the insulating layer 2 from the surface of the p-type silicon layer 3 in the SOI substrate.

In the p-type element forming region 3a, they are spaced apart and the collector region 6 of high impurity concentration p-type than the element formation region 3a (p ⁺⁾ of the well region 8 and the n-type (n ⁺⁾ is, An n-type (n ⁺ ) emitter region 5 is formed in the well region 8 on the surface side. Here, the well region 8 is formed to a depth reaching the insulating layer 2 from the surface of the element formation region 3a. Further, in the magnetic detection device of this embodiment, the p-type base region 4 is constituted by the well region 8 and a portion of the element formation region 3a interposed between the well region 8 and the collector region 6. Therefore, the magnetic detection device of the present embodiment has a transistor structure similar to that of the lateral npn transistor in the element formation region 3a.

  Further, on the surface side of the base region 4, a recombination region 7 made of an n-type impurity diffusion region that is separated from the well region 8 and the collector region 6 and functions as a recombination center of minority carriers in the base region 4 is formed. ing. In short, the recombination region 7 in this embodiment has a conductivity type different from that of the base region 4. The distance between the recombination region 7 and the collector region 6 is designed so that the above-described transistor structure can satisfy a predetermined breakdown voltage.

Further, an insulating film 12 made of a SiO ₂ film is formed on the surface side of the p-type silicon layer 3, and a base electrode 9, an emitter electrode 10, and a collector electrode 11 are contact holes 12 a formed in the insulating film 12. The base region 4 (well region 8), the emitter region 5 and the collector region 6 are electrically connected through 12b and 12c, respectively (the illustration of the insulating layer 12 and the electrodes 9 to 10 is omitted in FIG. 1A). ) Here, the insulating film 12 and the element isolation region 13 described above may be formed by, for example, an SOG (Spin on Glass) method or a CVD (Chemical Vapor Deposition) method. Further, a protective film 14 made of a Si ₃ N ₄ film is formed on the surface side of the insulating film 12, and pads (not shown) connected to the electrodes 9, 10, 11 are formed at appropriate portions of the protective film 14. An exposure hole (not shown) that exposes a) is opened. 1B is a cross-sectional view taken along the line XX ′ of FIG. 1A, but the insulating film 12 and the protective film 14 are not shown in FIG. 1A.

  Hereinafter, the operation of the magnetic detection device of this embodiment will be described.

In the magnetic detection device of the present embodiment, as shown in FIG. 1B, a DC voltage V _CE at which the collector electrode 11 is on the high potential side is applied between the collector electrode 11 and the emitter electrode 10 (that is, the collector A voltage at which the pn junction between the collector region 6 and the base region 4 is reverse-biased is applied between the electrode 11 and the emitter electrode 10), and the base electrode 9 is disposed between the base electrode 9 and the emitter electrode 10. By applying a DC voltage V _BE on the high potential side (that is, applying a forward bias voltage between the base electrode 9 and the emitter electrode 10), the pn junction between the base region 4 and the emitter region 5 is forward biased. Therefore, electrons are injected from the emitter region 5 into the base region 4, and the electrons injected into the base region 4 become minority carriers and move through the base region 4 by diffusion. Here, since the electrons injected into the base region 4 move according to the electron concentration gradient by the diffusion process, a part of the electrons move in the direction of the collector region 6 and extends from the collector region 6 to the base region 4 side. It reaches the end and is absorbed by the collector region 6 to become a collector current. An arrow A1 in FIG. 1B shows an example of the moving direction of electrons e ⁻ which are minority carriers in the base region 4 and move toward the collector region 6. When another part of the electrons injected into the base region 4 reaches the depletion layer d2 formed by the built-in voltage of the pn junction between the recombination region 7 and the base region 4, it is drawn into the recombination region 7. Disappears (disappears). Of course, some of the electrons injected into the base region 4 recombine with majority carrier holes and disappear. Therefore, a part of the electrons injected into the base region 4 disappears by recombination, and the rest reaches the collector region 6. For example, as a structural parameter of the magnetic detection device of the present embodiment, the impurity concentration of the element formation region 3a (impurity concentration of a portion of the base region 4 interposed between the well region 8 and the collector region 6) is 3 × 10 ^15. cm ⁻³ , the thickness is 1 μm, the impurity concentration of each of the emitter region 5, the collector region 6, and the recombination region 7 is 1 × 10 ²⁰ cm ⁻³ , and the diffusion depth is 0.5 μm. When the distance between the emitter region 5 and the collector region 6 is 20 μm, and the length of the recombination region 7 in the juxtaposed direction of the emitter region 5 and the collector region 6 (left and right direction in FIG. 1B) is 10 μm. FIG. 2 shows the result of simulating current-voltage characteristics when the DC voltage V _BE is constant at 0.8V. In FIG. 2, the horizontal axis represents the above-described DC voltage V _CE and the vertical axis represents the collector current Ic.

Here, when a magnetic field perpendicular to the direction of the current in the base region 4 (the left direction in FIG. 1B) is applied to the magnetic detection device of the present embodiment while the collector current Ic is flowing, The moving direction of e ⁻ is changed (bent) by the Lorentz force by the magnetic field. For example, when an external magnetic field H1 in the direction shown in the upper right lower part of FIG. 1B (external magnetic field H1 in the normal direction of the paper surface of FIG. 1B) is applied, the electron e ⁻ is changed to FIG. Since the Lorentz force F1 is received in the upward direction, the moving direction of the electron e ⁻ is deflected toward the recombination region 7 at an angle according to the strength of the magnetic field (magnetic flux density) (in FIG. 1B). Arrow A2 shows an example of the movement direction of electrons e ⁻ which are minority carriers in the base region 4 and whose movement direction is deflected by receiving the Lorentz force F1). In short, in the magnetic detection device of the present embodiment, when the external magnetic field H1 is applied, the recombination region 7 out of the electrons e ⁻ injected into the base region 4 is compared with the case where the external magnetic field H1 is not applied. The proportion of electrons e ⁻ that disappear due to surface recombination increases. As a result, the probability of arrival of electrons e ⁻ in the collector region 6 decreases, and the current value of the collector current Ic decreases.

On the other hand, when an external magnetic field H2 in the direction shown in the lower right lower part of FIG. 1B (that is, a magnetic field in the direction opposite to the above-described external magnetic field H1) is applied, the electron e ⁻ is changed to FIG. ) Is subjected to a Lorentz force in the downward direction, so that it is deflected toward the insulating layer 2. Therefore, as compared with the case where the external magnetic field H1 is applied, electrons e are injected into the base region 4 ^- electrons e to disappear is the surface recombination at the recombination region 7 of the ^- percentage of decreases, resulting in The probability of arrival of electrons e ^{− at} the collector region 6 increases, and the current value of the collector current Ic increases.

  As can be seen from the above description, also in the magnetic detection device of this embodiment, the current value of the collector current Ic changes according to the direction and magnitude (magnetic flux density) of the external magnetic field, as in the conventional magnetic transistor. By measuring the collector current as the sensor current, the direction and strength of the external magnetic field can be detected.

  By the way, in the magnetic detection device of this embodiment, the recombination region 7 is formed by doping impurities on the surface side of the base region 4 and is composed of an impurity diffusion region having a potential difference from the base region 4. In forming the coupling region 7, the recombination region 7 ′ is formed by reverse sputtering as in a conventional magnetic transistor by doping the impurity by thermal diffusion of the impurity, or ion implantation of the impurity and annealing after the ion implantation. The recombination region 7 can be formed with good reproducibility compared with the case of forming, and the variation in the recombination speed in the recombination region 7 during operation is reduced between products, so that the product is not sacrificed in sensitivity. It is possible to reduce variations in sensitivity between the two.

Further, in the magnetic detection device of this embodiment, the recombination process of minority carriers proceeds in the impurity diffusion region that constitutes the recombination region 7, so that it enters the interface between the recombination region 7 and the insulating film 12 from the surrounding environment. Therefore, it is possible to improve the long-term reliability of the sensitivity compared with the conventional magnetic transistor which is easily affected by ions entering the interface between the recombination region 7 ′ and the SiO ₂ film. Further, an insulating film 12 covering the entire surface of the recombination region 7 is formed on the surface side of the p-type silicon layer 3, and the recombination region 7 is electrically floating from the surroundings, so that an external magnetic field is applied. Since the ratio of minority carriers absorbed in the recombination region 7 can be reduced in a state where no recombination occurs, the sensitivity can be improved. Further, since the conductivity types of the recombination region 7 and the base region 4 are different, the minority carriers that have reached the depletion layer d2 spreading from the recombination region 7 to the base region 4 side are drawn into the recombination region 7 to be majority carriers. And recombination immediately and disappear, so that sensitivity equivalent to that of a conventional magnetic transistor can be obtained.

  If the magnetic detection apparatus described above is used as a geomagnetic sensor, a small azimuth sensor can be configured. Since the magnetic detection device of this embodiment is formed using a so-called SOI wafer, circuit elements for control, detection, temperature compensation, etc. can be integrated on the same substrate, and temperature correction is performed. Therefore, it is possible to realize a small magnetic detection device. Here, when the detection amplifier is integrated on the same substrate, the wiring length can be shortened, so that noise resistance against external noise can be improved. It is also possible to configure a composite sensor in which other sensors such as an acceleration sensor are integrated on the same substrate.

(Embodiment 2)
Hereinafter, the magnetic detection device of the present embodiment will be described with reference to FIGS.

  The basic configuration of the magnetic detection device of the present embodiment is substantially the same as that of the first embodiment, and is characterized in that the recombination region 7 is formed of a p-type impurity diffusion region having a higher concentration than the p-type base region 4. There is. That is, in this embodiment, the recombination region 7 is formed of an impurity diffusion region having the same conductivity type as the base region 4, and the recombination region 7 and the base region 4 have a potential difference due to a concentration difference. . In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

The basic operation of the magnetic detection device of the present embodiment is the same as that of the magnetic detection device of the first embodiment, and the first embodiment is provided between the collector electrode 11 and the emitter electrode 10 and between the base electrode 9 and the emitter electrode 10, respectively. When the same DC voltages V _CE and V _BE are applied, a part of the electrons injected from the emitter region 5 to the base region 4 is recombined in the recombination region 7 and the rest reaches the collector region 6. Similarly to the first embodiment, the angle at which the electrons e ⁻ that are minority carriers are deflected changes according to the direction and strength of the external magnetic fields H1 and H2, and the arrival probability of electrons to the collector region 6 changes. The same applies to the point where the collector current changes.

  Thus, in the magnetic detection device of this embodiment, as in the first embodiment, the recombination region 7 is formed by doping impurities on the surface side of the base region 4 and has an impurity diffusion region having a potential difference from the base region 4. Therefore, when the recombination region 7 is formed at the time of manufacture, the recombination is performed as in a conventional magnetic transistor by doping impurities by thermal diffusion of impurities or ion implantation of impurities and annealing after ion implantation. The recombination region 7 can be formed with good reproducibility compared with the case where the region 7 ′ is formed by reverse sputtering, and the variation in the recombination speed in the recombination region 7 during operation is reduced. It is possible to reduce variations in sensitivity between products without sacrificing. Further, in the magnetic detection device of this embodiment, the recombination region 7 has the same conductivity type as the base region 4 and has a potential difference with the base region 4 at a higher concentration than the base region 4, so that the recombination region 7 is reached. Since the minority carriers are recombined and disappear in the recombination region 7 having a higher concentration and a faster recombination speed than the base region 4, sensitivity equivalent to that of the conventional magnetic transistor can be obtained.

  In the configuration of the first embodiment shown in FIG. 1, the recombination region 7 and the base region 4 have different conductivity types, and the pn of the base region 4 and the recombination region 7 is within the base region 4 serving as a current path. Although the depletion layer d2 resulting from the junction is formed, in the magnetic detection device of the present embodiment, since the recombination region 7 has the same conductivity type as the base region 4, the recombination region 7 is present in the base region 4 serving as a current path. The depletion layer d2 resulting from the above is not formed, and the cross-sectional area of the minority carrier path (the cross-sectional area of the current path) in the base region 4 can be increased compared to the first embodiment. Therefore, in the magnetic detection device of the present embodiment, even if an SOI substrate having a p-type silicon layer 3 having a smaller thickness than that of the first embodiment is used, the cross-sectional area of minority carrier passages is made equal to that of the first embodiment. Since the change between the collector current in the neutral state where there is no external magnetic field and the collector current when the external magnetic field is applied can be as large as in the first embodiment, it is possible to prevent a decrease in sensitivity. Therefore, by reducing the thickness of the p-type silicon layer 3, the formation of the isolation groove 3b and the formation of the element isolation region 13 during manufacture are facilitated.

  In addition, since the distance between the collector region 6 and the recombination region 7 necessary for ensuring a predetermined breakdown voltage is smaller than that in the first embodiment, recombination is possible in comparison with the first embodiment if the same breakdown voltage is used. There is an advantage that the region 7 can be brought closer to a position closer to the collector region 6 and the sensitivity can be increased. In other words, in the magnetic detection device of the present embodiment, it is possible to increase the sensitivity without lowering the breakdown voltage as compared with the first embodiment by appropriately designing the position where the recombination region 7 is formed.

(Embodiment 3)
Hereinafter, the magnetic detection device of the present embodiment will be described with reference to FIGS. 4 (a) and 4 (b).

  The basic configuration of the magnetic detection device of the present embodiment is substantially the same as that of the first embodiment, and the recombination region 7 is formed of an n-type polycrystalline silicon film formed on the p-type base region 4. There are features. That is, in this embodiment, the recombination region 7 is formed of a polycrystalline semiconductor film having a conductivity type different from that of the base region 4, and the recombination region 7 and the base region 4 have a potential difference. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted.

The basic operation of the magnetic detection device of the present embodiment is the same as that of the magnetic detection device of the first embodiment, and the first embodiment is provided between the collector electrode 11 and the emitter electrode 10 and between the base electrode 9 and the emitter electrode 10, respectively. By applying the same DC voltages V _CE and V _BE as those in FIG. 4, a part of the electrons injected from the emitter region 5 to the base region 4 is recombined in the recombination region 7 and the rest reaches the collector region 6 ( A depletion layer d3 spreads on the base region 4 side in the recombination region 7, and this depletion layer d3 has the same role as the depletion layer d2 in the first embodiment). Similarly to the first embodiment, the angle at which the electrons e ⁻ that are minority carriers are deflected changes according to the direction and strength of the external magnetic fields H1 and H2, and the arrival probability of electrons to the collector region 6 changes. The same applies to the point where the collector current changes.

  Therefore, in the magnetic detection device of the present embodiment, the recombination region 7 is formed on the base region 4 and is made of a polycrystalline semiconductor film doped with impurities so as to have a potential with the base region 4. In forming the bonding region 7, the formation of a polycrystalline semiconductor film by CVD or the like and the thermal diffusion of impurities into the polycrystalline semiconductor film, or the formation of a polycrystalline semiconductor film by CVD or the like and the polycrystalline semiconductor Recombination like a conventional magnetic transistor by doping impurities by ion implantation of impurities into the film and annealing after ion implantation, or doping of impurities during deposition of a polycrystalline semiconductor film by CVD or the like Compared with the case where the region 7 ′ is formed by reverse sputtering, the recombination region 7 can be formed with good reproducibility, and recombination during operation is possible. Since the variation between the recombination rate of the products in the area 7 is reduced, thereby reducing the variation in sensitivity among products without sacrificing sensitivity. Further, since the recombination process of minority carriers proceeds in the polycrystalline semiconductor film constituting the recombination region 7, it is not easily affected by ions that have entered the interface between the recombination region 7 and the insulating film 12 from the surrounding environment, The long-term reliability of sensitivity can be improved compared to conventional magnetic transistors. Further, an insulating film 12 covering the entire surface of the recombination region 7 is formed on the surface side of the p-type silicon layer 3, and the recombination region 7 is electrically floating from the surroundings, so that an external magnetic field is applied. Since the ratio of minority carriers absorbed in the recombination region 7 can be reduced in a state where no recombination occurs, the sensitivity can be improved. Further, since the conductivity types of the recombination region 7 and the base region 4 are different, the minority carriers that have reached the depletion layer d2 spreading from the recombination region 7 to the base region 4 side are drawn into the recombination region 7 to be majority carriers. And recombination immediately and disappear, so that sensitivity equivalent to that of a conventional magnetic transistor can be obtained.

  Incidentally, in the configuration of the first embodiment shown in FIG. 1, the recombination region 7 is formed in the base region 4. However, in the magnetic detection device of this embodiment, the recombination region 7 is placed on the surface of the base region 4. Since it is formed, the cross-sectional area of the minority carrier passage (the cross-sectional area of the current passage) in the base region 4 can be increased as compared with the first embodiment. Therefore, in the magnetic detection device of the present embodiment, even if an SOI substrate having a p-type silicon layer 3 having a smaller thickness than that of the first embodiment is used, the cross-sectional area of minority carrier passages is made equal to that of the first embodiment. Since the change between the collector current in the neutral state where there is no external magnetic field and the collector current when the external magnetic field is applied can be as large as in the first embodiment, it is possible to prevent a decrease in sensitivity. Therefore, by reducing the thickness of the p-type silicon layer 3, the formation of the isolation groove 3b and the formation of the element isolation region 13 during manufacture are facilitated.

(Embodiment 4)
Hereinafter, the magnetic detection device of this embodiment will be described with reference to FIGS. 5 (a) and 5 (b).

  The basic configuration of the magnetic detection device of the present embodiment is substantially the same as that of the third embodiment, and the recombination region 7 is a p-type polycrystal having a higher impurity concentration than the base region 4 formed on the p-type base region 4. It is characterized by being composed of a silicon film. That is, in this embodiment, the recombination region 7 is formed of a polycrystalline semiconductor film having the same conductivity type as that of the base region 4 and having an impurity concentration higher than that of the base region 4. There is a potential difference due to the concentration difference. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 3, and description is abbreviate | omitted. Further, the basic operation is the same as that of the third embodiment, and the description thereof is omitted.

  Thus, in the magnetic detection device of this embodiment, as in the third embodiment, the polycrystalline semiconductor film doped with impurities so that the recombination region 7 is formed on the base region 4 and has the potential with the base region 4. Therefore, the recombination region 7 can be formed with good reproducibility compared to the case where the recombination region 7 'is formed by reverse sputtering as in the conventional magnetic transistor, and recombination in the recombination region 7 during operation is possible. Since variations in bonding speed between products are reduced, it is possible to reduce variations in sensitivity between products without sacrificing sensitivity. Further, since the recombination region 7 has the same conductivity type as that of the base region 4 and has a potential difference from the base region 4 at a higher concentration than the base region 4, minority carriers that have reached the recombination region 7 are smaller than those in the base region 4. Therefore, the recombination region 7 having a high recombination speed and a high recombination speed disappears, so that sensitivity equivalent to that of the conventional magnetic transistor can be obtained.

  In the configuration of the third embodiment shown in FIG. 4, the recombination region 7 and the base region 4 have different conductivity types, and the pn of the base region 4 and the recombination region 7 is within the base region 4 serving as a current path. Although the depletion layer d3 resulting from the junction is formed, in the magnetic detection device of this embodiment, since the recombination region 7 has the same conductivity type as the base region 4, the recombination region 7 is in the base region 4 serving as a current path. The depletion layer d3 resulting from the above is not formed, and the cross-sectional area of the minority carrier path (the cross-sectional area of the current path) in the base region 4 can be increased compared to the third embodiment. Therefore, in the magnetic detection device of the present embodiment, even if an SOI substrate having a p-type silicon layer 3 having a smaller thickness than that of the third embodiment is used, the cross-sectional area of the minority carrier passage is made equal to that of the third embodiment. Since the change between the collector current in the neutral state where there is no external magnetic field and the collector current when the external magnetic field is applied can be as large as in the third embodiment, it is possible to prevent a decrease in sensitivity. Therefore, by reducing the thickness of the p-type silicon layer 3, the formation of the isolation groove 3b and the formation of the element isolation region 13 during manufacture are facilitated.

  Further, in the magnetic detection device of the present embodiment, the distance between the collector region 6 and the recombination region 7 necessary for ensuring a predetermined breakdown voltage is shorter than that of the configuration of the third embodiment. If the same breakdown voltage is used, the recombination region 7 can be brought closer to the collector region 6 and the sensitivity can be increased.

(Embodiment 5)
Hereinafter, the magnetic detection device of the present embodiment will be described with reference to FIGS. 6 (a) and 6 (b).

  The basic configuration of the magnetic detection device of this embodiment is substantially the same as that of the third embodiment, and is characterized in that the recombination region 7 is formed of a metal film in Schottky contact with the surface of the p-type base region 4. That is, in this embodiment, a Schottky barrier is formed at the interface between the recombination region 7 made of a metal film on the base region 4 and the base region 4, and the recombination region 7 has a potential difference from the base region 4. ing. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 3, and description is abbreviate | omitted. Further, the basic operation is the same as that of the third embodiment, and the description thereof is omitted.

  Therefore, in the magnetic detection device of the present embodiment, when the recombination region 7 is formed, the recombination region 7 can be formed with good reproducibility by forming a metal film on the base region 4. Since variations in the recombination speed in the recombination region 7 between products are reduced, it is possible to reduce variations in sensitivity between products without sacrificing sensitivity. Further, since the recombination process of minority carriers proceeds in the metal film constituting the recombination region 7, it is difficult to be influenced by ions entering the interface between the recombination region 7 and the insulating film 12 from the surrounding environment. The long-term reliability of the sensitivity can be improved compared to the magnetic transistor. Further, an insulating film 12 covering the entire surface of the recombination region 7 is formed on the surface side of the p-type silicon layer 3, and the recombination region 7 is electrically floating from the surroundings, so that an external magnetic field is applied. Since the ratio of minority carriers absorbed in the recombination region 7 can be reduced in a state where no recombination occurs, the sensitivity can be improved.

  Further, in the magnetic detection device of the present embodiment, the height of the Schottky barrier can be designed to be smaller than the band gap of silicon and spread from the Schottky junction between the recombination region 7 made of a metal film and the p-type base region 4. Since the width of the depletion layer d4 can be made smaller than the depletion layer d3 extending from the pn junction between the recombination region 7 made of the n-type polycrystalline silicon film and the p-type base region 4 in the magnetic detection device of the third embodiment. While reducing the thickness of the p-type silicon layer 3 as compared with the third embodiment, it is possible to prevent the decrease in sensitivity by making the cross-sectional areas of minority carrier paths equal, and to reduce the thickness of the p-type silicon layer 3. Thus, it becomes easy to form the isolation groove 3b and the element isolation region 13 that reach the insulating layer 2 from the surface of the p-type silicon layer 3.

(Embodiment 6)
Hereinafter, the magnetic detection device of the present embodiment will be described with reference to FIGS. 7 (a) and 7 (b).

  The basic configuration of the magnetic detection device of the present embodiment is substantially the same as that of the first embodiment, and the recombination region 7 is within the recombination region 7 composed of an n-type impurity diffusion region (hereinafter referred to as a first impurity diffusion region). A p-type impurity diffusion region (hereinafter referred to as a second impurity diffusion region) 17 having a conductivity type different from that of the recombination region 7 is formed on the surface side of the first impurity diffusion region 17 and formed on the second impurity diffusion region 17. The electrode 18 is characterized in that it is electrically connected to the base electrode 9 through a metal wiring 19 formed on the insulating film 12. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted. Further, the basic operation is the same as that of the first embodiment, and the description thereof is omitted.

  Thus, also in the magnetic detection device of the present embodiment, as in the first embodiment, the recombination region 7 is formed by doping impurities on the surface side of the base region 4 and has a potential difference from the base region 4. Since it is composed of one impurity diffusion region, the recombination region 7 can be formed with good reproducibility, and variations in the recombination speed in the recombination region 7 during operation are reduced, so that sensitivity is sacrificed. It is possible to reduce variations in sensitivity between products without any problems. In addition, since the minority carrier recombination process proceeds in the first impurity diffusion region constituting the recombination region 7, it is less affected by ions entering from the surrounding environment and has a longer sensitivity than conventional magnetic transistors. Reliability can be improved.

  Further, in the magnetic detection device of the present embodiment, the second impurity diffusion region 17 having a conductivity type different from that of the recombination region 7 is formed on the surface side of the recombination region 7, and the surface of the second impurity diffusion region 17 is formed. Since the electrode 18 formed on the side and electrically connected to the second impurity diffusion region 17 is electrically connected to the base electrode 9, the recombination region 7 formed of the first impurity diffusion region and the second impurity diffusion region 17 The impurity diffusion region 17 forms a diode, and carriers necessary for recombination of minority carriers that have diffused through the base region 9 and reached the recombination region 7 are base region 4−base electrode 9−. The metal wiring 19 is injected into the second impurity diffusion region 17 through the path of the electrode 18 electrically connected to the second impurity diffusion region 17, the second impurity diffusion region 17, and the recombination region 7 (that is, Pull into recombination zone 7 From the base region 4 to the recombination region 7 through the base electrode 9 and the second impurity diffusion region 17 so as to satisfy the neutralization condition with the electrons that are minority carriers). The holes injected into the impurity diffusion region 17 and the electrons drawn into the recombination region 7 are recombined, so that the recombination is more effectively promoted and the Hall effect due to carrier accumulation is suppressed, and the base region 4 The minority carriers therein are easily deflected and the sensitivity is improved.

  When the recombination region 7 and the base region 4 are electrically connected without providing the second impurity diffusion region 17, the recombination region is generated by the potential of the base region 4 even in a neutral state without an external magnetic field. 7, most of the minority carriers are extracted from the base region 4, which causes a problem that the change in the collector current due to the change in the external magnetic field becomes small. In the magnetic detection device of this embodiment, the recombination region Since the diode is formed at the junction of the first impurity diffusion region 17 and the second impurity diffusion region 17 that constitute the structure 7, occurrence of such a problem can be prevented.

(Embodiment 7)
Hereinafter, the magnetic detection device of the present embodiment will be described with reference to FIGS. 8 (a) and 8 (b).

  The basic configuration of the magnetic detection device of the present embodiment is substantially the same as that of the sixth embodiment, and instead of providing the second impurity diffusion region 17 in the sixth embodiment, the surface of the recombination region 7 formed of an n-type impurity diffusion region. On the side, a p-type polycrystalline silicon film 27 doped with impurities so as to have a conductivity type different from that of the recombination region 7 is formed, and is formed on the polycrystalline silicon film 27 and electrically connected to the polycrystalline silicon film 27. The difference is that the electrode 28 is electrically connected to the base electrode 9 through a metal wiring 29 formed on the insulating film 12. Here, in the present embodiment, the polycrystalline silicon film 27 constitutes a polycrystalline semiconductor film doped with impurities so as to have a conductivity type different from that of the recombination region 7. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 6, and description is abbreviate | omitted. Further, the basic operation is the same as that of the sixth embodiment, and the description thereof is omitted.

  Thus, in the magnetic detection device of this embodiment, as in the sixth embodiment, the recombination region 7 is formed by doping impurities on the surface side of the base region 4 and has a potential difference from the base region 4. Since it is composed of one impurity diffusion region, the recombination region 7 can be formed with good reproducibility, and variations in the recombination speed in the recombination region 7 during operation are reduced, so that sensitivity is sacrificed. It is possible to reduce variations in sensitivity between products without any problems. In addition, since the minority carrier recombination process proceeds in the first impurity diffusion region constituting the recombination region 7, it is less affected by ions entering from the surrounding environment and has a longer sensitivity than conventional magnetic transistors. Reliability can be improved.

  In the magnetic detection device of this embodiment, carriers (holes for neutralizing electrons) necessary for recombination of minority carriers that have reached the recombination region 7 from the base region 4 are generated in the base region 4-base. Since the electrode 9 -the metal wiring 29 -the electrode 28 electrically connected to the polycrystalline silicon film 27 -the polycrystalline silicon film 27 -the recombination region 7 is injected into the recombination region 7, the recombination can be performed more effectively. Coupling is promoted to suppress the Hall effect due to carrier accumulation, and minority carriers in the base region 4 are easily deflected to improve sensitivity.

  In the case where the recombination region 7 and the base region 4 are electrically connected without providing the polycrystalline silicon film 27, the recombination region is hardly passed through the recombination region due to the potential of the base region 4 even in a neutral state without an external magnetic field. The minority carriers are extracted from the base region 4 and the change in the collector current due to the change in the external magnetic field is reduced. However, in the magnetic detection device of this embodiment, the recombination region 7 is configured. Since the diode is formed by the junction of the impurity diffusion region and the polycrystalline silicon film 27, the occurrence of such a problem can be prevented.

  In the magnetic detection device of the sixth embodiment, it is necessary to form the first impurity diffusion region and the second impurity diffusion region 17 constituting the recombination region 7 by double diffusion. In the detection device, it is not necessary to form another impurity diffusion region (the above-described second impurity diffusion region 17) in the recombination region 7 formed in the base region 4, so recombination as in the sixth embodiment. Compared with the case where the second impurity diffusion region 17 needs to be formed in the region 7, the diffusion depth of the impurity diffusion region constituting the recombination region 7 can be reduced, and the thickness of the p-type silicon layer 3 can be reduced. Although the thickness of the p-type silicon layer 3 can be reduced by reducing the thickness of the p-type silicon layer 3, the cross-sectional area of the minority carrier passages can be made equal to each other. Reaching the separation groove 3b and the element Formation of the isolation region 13 is facilitated.

(Embodiment 8)
Hereinafter, the magnetic detection device of this embodiment will be described with reference to FIGS. 9 (a) and 9 (b).

  The basic configuration of the magnetic detection device of the present embodiment is substantially the same as that of the seventh embodiment. On the surface side of the recombination region 7, the same conductivity type as that of the recombination region 7 and a lower impurity concentration than the recombination region 7. An electrode 38 formed on the polycrystalline silicon film 37 and electrically connected to the polycrystalline silicon film 37 is formed on the base electrode 9 via the metal wiring 39 formed on the insulating film 12. And is electrically connected. Here, in the present embodiment, the polycrystalline silicon film 37 constitutes a polycrystalline semiconductor film having the same conductivity type as the recombination region 7 and having a lower impurity concentration than the recombination region 7. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 7, and description is abbreviate | omitted. Further, the basic operation is the same as that of the seventh embodiment, and the description thereof is omitted.

  Thus, also in the magnetic detection device of this embodiment, as in the seventh embodiment, the recombination region 7 is formed by doping impurities on the surface side of the base region 4 and has an impurity having a potential difference from the base region 4. Since it consists of a diffusion region, the recombination region 7 can be formed with good reproducibility, and there is less variation between products in the recombination speed in the recombination region 7 during operation. It is possible to reduce variations in sensitivity between the two. Further, since the recombination process of minority carriers proceeds in the impurity diffusion region constituting the recombination region 7, it is not easily affected by ions entering from the surrounding environment, and has a long-term reliability of sensitivity compared to the conventional magnetic transistor. Improvements can be made.

  In the magnetic detection device of this embodiment, a polycrystalline silicon film 37 having the same conductivity type as the recombination region 7 and having a lower impurity concentration than the recombination region 7 is formed on the surface side of the recombination region 7. Since the electrode 38 formed on the crystalline silicon film 37 and electrically connected to the polycrystalline silicon film 37 is electrically connected to the base electrode 9, minority carriers that have reached the recombination region 7 from the base region 4. Electrode 38-polycrystalline silicon in which carriers (holes for neutralizing electrons) necessary for recombination are electrically connected to base region 4-base electrode 9-metal wiring 39-polycrystalline silicon film 37 Since the film 37 is injected into the recombination region through the path of the recombination region 7, the recombination is more effectively promoted, the Hall effect due to carrier accumulation is suppressed, and minority carriers in the base region 4 are deflected. Sensitivity is improved become easier.

  In the case where the recombination region 7 and the base region 4 are electrically connected without providing the polycrystalline silicon film 37, the recombination region 7 passes through the recombination region 7 due to the potential of the base region 4 even in a neutral state without an external magnetic field. Most minority carriers are extracted from the base region 4, which causes a problem that the change in the collector current due to the change in the external magnetic field is reduced. However, in the magnetic detection device of this embodiment, the polycrystalline silicon film 37. Functions as a resistor inserted between the recombination region 7 and the base region 4, so that such a problem can be prevented. Further, since it is not necessary to form another impurity diffusion region for forming a resistor in the recombination region 7 formed in the base region 4, the minority carrier of the p-type silicon layer 3 can be reduced while reducing the thickness. Since the cross-sectional area of the passage is equivalent to the case where another impurity diffusion region is formed, it is possible to prevent a decrease in sensitivity. By reducing the thickness of the p-type silicon layer 3, the surface of the p-type silicon layer 3 can be reduced. Formation of the isolation trench 3b and the element isolation region 13 reaching the insulating layer 2 is facilitated.

(Embodiment 9)
Hereinafter, the magnetic detection device of the present embodiment will be described with reference to FIGS. 10 (a) and 10 (b).

  The basic configuration of the magnetic detection device of the present embodiment is substantially the same as that of the first embodiment, and an electrode 47 formed on the surface side of the recombination region 7 and electrically connected to the recombination region 7 is provided on the support substrate 1. It is characterized in that it is electrically connected to the back electrode 51 formed on the back surface. In addition, the same code | symbol is attached | subjected to the component similar to Embodiment 1, and description is abbreviate | omitted. Further, the basic operation is the same as that of the first embodiment, and the description thereof is omitted.

  Thus, in the magnetic detection device of this embodiment, the electrode 47 formed on the surface side of the recombination region 7 and electrically connected to the recombination region 7 is electrically connected to the support substrate 1. Carriers that have entered the recombination region 7 can be prevented from accumulating in the recombination region 7, the Hall effect due to carrier accumulation can be suppressed, and minority carriers in the base region 4 can be easily deflected, resulting in sensitivity. Will improve.

(Reference example)
Hereinafter, the magnetic detection device of this reference example will be described with reference to FIGS. 11 (a) and 11 (b).

  The basic configuration of the magnetic detection device of this reference example is substantially the same as that of the first embodiment, and is provided with an electrode 47 formed on the surface side of the recombination region 7 and electrically connected to the recombination region 7. Is different.

Thus, the magnetic sensing device of the present embodiment can be applied to any direct-current voltage V _R from the external power supply between the electrodes 47 and the emitter electrode 10.

  Here, in this reference example, it is possible to optimize the potential of the recombination region 7 by injecting holes for erasing the electrons drawn into the recombination region 7 from the external power source. If the potential of the recombination region 7 is made equal to the potential of the base region 4, even in a neutral state where there is no external magnetic field, most of the minority carriers are extracted from the base region 4 through the recombination region 7 due to the potential of the base region 4. There is a problem that the change in the collector current due to the change in the external magnetic field becomes small. However, in the magnetic detection device of this reference example, by providing an arbitrary potential with the external power supply, the above diodes and resistors are not provided. , Sensitivity can be improved.

DESCRIPTION OF SYMBOLS 1 Support substrate 2 Insulating layer 3 P-type silicon layer 3a Element formation area 4 Base area 5 Emitter area 6 Collector area 7 Recombination area 8 Well area 9 Base electrode 10 Emitter electrode 11 Collector electrode 12 Insulating film 13 Element isolation area 14 Protective film

Claims (3)

  A second conductivity type emitter region formed in a first conductivity type semiconductor layer on the insulating layer; a second conductivity type collector region formed in the semiconductor layer and spaced apart from the emitter region; A base region of a first conductivity type interposed between the emitter region and the collector region in a semiconductor layer; an emitter electrode formed on a surface side of the emitter region and electrically connected to the emitter region; A base electrode formed on the surface side of the base region and electrically connected to the base region; a collector electrode formed on the surface side of the collector region and electrically connected to the collector region; and the base region A recombination region formed as a recombination center of minority carriers in the base region, which is formed on the surface side so as to be separated from the emitter region and the collector region. And a voltage at which a pn junction between the collector region and the base region is reverse-biased is applied between the collector electrode and the emitter electrode, and between the base electrode and the emitter electrode. A magnetic detection device in which a collector current changes when an external magnetic field changes a ratio of recombination in the recombination region of the minority carriers injected into the base region in a state where a forward bias voltage is applied. The recombination region is formed of a polycrystalline semiconductor film formed on the base region and doped with impurities so as to have a potential difference from the base region, and on the surface side of the semiconductor layer, the recombination region A magnetic detection device comprising an insulating film covering the entire surface.   The magnetic detection device according to claim 1, wherein a conductivity type of the recombination region is a second conductivity type.   2. The magnetic detection device according to claim 1, wherein the conductivity type of the recombination region is a first conductivity type, and the impurity concentration of the recombination region is higher than the impurity concentration of the base region.

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