WO2005013376A1

WO2005013376A1 - Semiconductor magnetic sensor and magnetism measuring instrument using same

Info

Publication number: WO2005013376A1
Application number: PCT/JP2004/010967
Authority: WO
Inventors: Mitsuteru Kimura
Original assignee: Mitsuteru Kimura
Priority date: 2003-07-31
Filing date: 2004-07-30
Publication date: 2005-02-10
Also published as: JP4287905B2; JP2005049179A

Abstract

A semiconductor magnetic sensor which has an ultrasmall size, consumes small power, hardly varies with time, has a high sensitivity, and can have various integrated circuits, and a compact magnetism measuring instrument mounted with the semiconductor magnetic sensor. The semiconductor magnetic sensor has a bipolar or MOS transistor structure. A recombination region (R) is formed in the region corresponding to the base of the structure. The recombination rate of the minority carries injected into the base is varied by the Lorentz force due to an external magnetic field (H), and the strength and direction of the external magnetic field (H) are measured from the variation of the collector or drain current. If the recombination region (R) is of a type using a p-n junction, the recombination rate of the minority carriers can be also controlled by applying a bias voltage.

Description

Specification

Semiconductor magnetic sensor and magnetic measuring device using the same

Technical field

TECHNICAL FIELD [0001] The present invention relates to a magnetic sensor using a semiconductor, which can detect the magnitude and direction of a magnetic field with high sensitivity, small size, low power consumption, and a magnetic measurement device using the same. Background art

Conventionally, there has been a magnetic diode (for example, Japanese Patent Application Laid-Open No. 2002-134758) as a semiconductor magnetic sensor invented by the present inventors. This magnetic diode was basically a two-terminal pin structure, and its operating principle was as follows. The i-region, which is an intrinsic semiconductor region, has a recombination region, and a forward noise is applied between the p-type region and the n-type region to apply an external magnetic field in the double injection state of the carrier. When H is applied and both electrons (1) and holes (+), which are double-injected carriers, are bent to the recombination region side by Lorentz force, both flowing carriers disappear due to recombination and decrease. In addition, since the double injection tends to be suppressed, the diode current decreases. On the other hand, when both of the double-injected electron and hole carriers are bent to the opposite side to the recombination region, the non-recombination region where recombination is unlikely occurs. It was a semiconductor diode magnetic sensor based on the principle that a large diode current flows.

[0003] Further, since the injection carrier is formed on the thin SOI layer of the SOI substrate, the injected carrier easily reaches the recombination region formed on the SOI surface even with a small external magnetic field H. A low driving voltage and low power consumption are required.

[0004] Conventionally, a magnetic transistor is generally known. This is because the carriers injected into the base B from the emitter E of the bipolar transistor are minority carriers in the base B region, and the injected minority carriers are electrically connected to the presence of free majority carriers in the base B. It flows into the reverse-biased collector C while maintaining neutrality.However, when an external magnetic field H is applied in a direction perpendicular to the flow, it is deflected without generating a Hall voltage due to Lorentz force. C is divided into two parts, a collector C1 and a collector C2, and the injected minority carrier force deflected by the oral Lenz force. Since a large amount flows in a small amount, the magnitude and direction of the external magnetic field H can be known by differential amplification of these different collector currents.

[0005] Conventionally, a MOSFET is formed instead of a magnetic transistor of a bipolar transistor, two drains corresponding to two collectors are provided, and injection is performed in a bipolar transistor-like operation region by adjusting gate voltage application. A MAGFET has been reported as a magnetic sensor based on the same operating principle as a magnetic transistor, which detects the current difference between two drains by deflecting the minority carrier in the channel region by the Lorentz force.

[0006] In conventional magnetometers, since there is no high-sensitivity sensor capable of measuring a weak magnetic field equivalent to terrestrial magnetism that is completely compatible with the CMOS process, high-frequency generation of several hundred MHz is required. Some magnetic sensors measure impedance, but in this case, the combination of a special magnetic material and the like and the manufacturing process are required. With the advancement of the technology, it became necessary to use an expensive magnetic field measurement device. Even high-sensitivity magnetic sensors such as GMR and TMR have magnetic sensitivity peaks in the weak magnetic field region, so to obtain a digital signal such as an ON / OFF signal indicating whether a weak magnetic field exists. Suitable force Suitable for measuring a wide range of magnetic fields, so suitable for a wide range of magnetic field measurement devices.

[0007] In the conventional double injection type pin magnetic diode (Japanese Patent Application Laid-Open No. 2002-134758), even if a recombination region R formed by a pn junction is formed in a region where a drift electric field is generated, the electric field remains in the i layer. Even if a pn junction is formed during the concentration, the length of the i-layer becomes short-circuited due to the existence of the region, the electric field distribution becomes complicated, and the recombination region R There was no effect.

Disclosure of the invention

Problems to be solved by the invention

[0008] However, this type of conventional magnetic sensor has a feature that the semiconductor magnetic sensor can be formed of a semiconductor such as silicon, so that it is compatible with a CMOS process and is easily integrated. MAGFET is a semiconductor magnetic sensor that is a magnetic diode according to the inventor's invention with extremely low sensitivity. There has been a demand for a semiconductor magnetic sensor having an even higher magnetic sensitivity so that the magnetic field can be detected.

[0009] Further, in a magnetic diode, a double injection of electrons and holes causes a recombination current to flow even if they are recombined, so that a current change due to a very large external magnetic field cannot be obtained. There was also a problem that it could not grow.

[0010] In addition, it has been desired to form a recombination region R that is reproducible and has an extremely small change with time and is easy to design.

[0011] The present invention has the same basic principle as the conventional semiconductor magnetic sensor described above, which utilizes the magnetoresistance change based on the deflection and recombination of the double injection carrier of the semiconductor diode by the magnetic field, but the injection into the base is performed. A semiconductor magnetic sensor that operates as a transistor that changes the recombination ratio of minority carriers in the selected base by an external magnetic field H. It can use the latest integration technology of semiconductors, and is ultra-small, low power consumption, and a stable recombination region. With the adoption of a semiconductor magnetic sensor that has high sensitivity with extremely little change over time and can integrate drive circuits, amplifier circuits, and various compensation circuits, it is also inexpensive, low power consumption, It is an object to provide a measuring device.

Means for solving the problem

[0012] To achieve the above object, a semiconductor magnetic sensor according to claim 1 of the present invention provides a semiconductor magnetic sensor in which minority carriers are injected into a region B of one conductivity type (for example, p-type) of a semiconductor. A region E of a type (for example, n-type) and a region C which is made of the same conductivity type or metal as the region E and receives the injected minority carriers are arranged close to each other. In a region B between the region C and the region C, a recombination region R for recombining the injected minority carriers is provided, and when an external magnetic field H is applied, the minority injected from the region E to the region B is provided. The recombination region R is arranged so that the rate at which carriers are deflected by the Lorentz force and recombine in the recombination region R changes, and the injected minority that reaches the region C by the external magnetic field H is arranged. The number of carriers changes and the area by this number of minority carriers It is characterized in that information such as the magnitude and direction of the external magnetic field H is obtained from changes in the current flowing through C.

[0013] More specifically, the semiconductor magnetic sensor of the present invention can be roughly divided into a bipolar transistor type semiconductor magnetic sensor and a MOSFET type (or MISFET type) semiconductor magnetic sensor. It can be divided into air sensors.

First, the bipolar transistor type semiconductor magnetic sensor will be described as follows.

[0015] The region B is a p-type region of a p-type Si substrate as an example. In this region, an n-type region E as an emitter and an n-type region C as a collector, and electrons as minor carriers injected from the emitter into the p-type region B as a base region reach the collector region C. The gap is formed as close as possible (the base length, which is the distance between the emitter region E and the collector region C, is sufficiently smaller than the diffusion distance of electrons as minority carriers). A carrier recombination region R is formed in the base region B between the emitter region E and the collector region C at a position slightly shifted from the axis connecting the emitter region E and the collector region C. A forward bias voltage is applied to the pn junction between the emitter region E and the base region B, and electrons, which are minority carriers in the p-type base region B, are injected from the emitter region E into the base region B. And the minority carrier electrons injected by the reverse bias voltage applied to the collector region C are swept out to the collector region C. At this time, of the electrons injected into the base region B, the amount diffused into the recombination region R is lost by the recombination, but the remaining amount reaches the collector region C and is swept out to become a collector current. The electrons of the minority carriers injected into the base region B are mainly bent into the recombination region R by the Lorentz force of the applied external magnetic field H while flowing mainly through the collector region C by diffusion. Since the number reaching the collector region C decreases, the collector current decreases. On the other hand, when it is bent in the direction away from the recombination region R on average by the Lorentz force of the external magnetic field H applied, the minority carrier electrons lost in the recombination region R decrease and reach the collector region C. Since the number reached reaches, the collector current increases accordingly. In this way, information such as the magnitude and direction of the external magnetic field H can be obtained from the magnitude of the collector current and the spatial configuration of the external magnetic field H with respect to the semiconductor magnetic sensor.

[0016] In a conventional semiconductor magnetic sensor using a double injection carrier using a pin diode, the carrier injected into the i region travels by drift due to an electric field, and the Lorentz force increases as the drift speed increases. S, since the interaction time with the traveling carrier is short, the bending of the carrier is eventually reduced. Rather, like the semiconductor magnetic sensor of the present invention, the base When the minority carrier moves slowly by diffusion in the storage region B, the interaction time is longer, and the bend is greatly bent, and the proportion of minority carriers that are recombined and lost in the recombination region R increases. The result is a high-sensitivity magnetic sensor. Since the junction between the base region B and the collector region C has a reverse bias, the minority carrier electrons injected by the application of the external magnetic field H are bent toward the recombination region R, and Unless it is lost by recombination and does not reach the collector region C, almost no collector current flows, resulting in a large collector current change rate and a large magnetic sensitivity.

Next, the MOSFET type semiconductor magnetic sensor will be described as follows, corresponding to the bipolar transistor type semiconductor magnetic sensor.

The n-type source S of the MOSFET corresponds to the n-type emitter region E of the bipolar transistor type semiconductor magnetic sensor described above, and the n-type drain D corresponds to the collector region C. The base region B corresponds to the channel region immediately below the gate oxide film and the p-type substrate. However, if an n-type channel is completely formed by applying a gate voltage, etc., the carrier will no longer be a minority carrier, and in majority carrier conduction, a hole electric field will be formed and the carrier will not bend due to an external magnetic field. It is necessary to operate by applying an appropriate gate voltage so that it operates as a bipolar transistor like the region, and to inject minority carrier electrons into the still p-type channel to reach the drain D. For example, if a recombination region R is formed at the interface between the channel and the gate oxide film, the operation principle is the same as that of the bipolar transistor type semiconductor magnetic sensor, and the change in the drain current corresponding to the collector current causes The magnitude and direction of the magnetic field H can be detected.

Of course, the MISFET type, which can be used as a MISFET instead of a MOSFET, is easier to create the recombination region R immediately below the gate.

Also, the recombination region R may be formed not only immediately below the gate but also at a position shifted therefrom.

In the above-mentioned bipolar transistor type semiconductor magnetic sensor and the MOSFET type or MISFET type semiconductor magnetic sensor, the collector region C and the drain D as the region C are different from the base region B as the region B. The force S, which was an example using a conductive n-type semiconductor, is used as a metal to form a Schottky junction with the base region B, which is then reverse biased. Then, even if the injected minority carrier is swept out, it operates on the same principle as described above.

[0021] As a recombination region R, an argon gas and a small amount of oxygen gas are flowed, and sputtering is performed using the ion of these gases to form defects on the surface, or the surface is chemically roughened using a solution or the like. Alternatively, it may be formed using a combination of a physical sputtering defect and a chemical reaction. Since defects in the crystal are repaired and crystallized by heat treatment, a small amount of oxygen is introduced at the time of sputtering to form an oxide at the defect, which impedes crystallization. In addition, it is possible to prevent the aging and prevent the aging. Of course, after forming defects on the surface by sputtering only with argon gas, thermal oxidation can be used to partially oxidize the vicinity of the defects or to perform chemical treatment to prevent aging due to crystallization. it can.

[0022] Gold, platinum, or the like may be added by an ion implantation method or a diffusion technique to function as a killer center to form a recombination region R that promotes carrier recombination.

[0023] Alternatively, silicon, germanium, or the like may be deposited on the surface to form a recombination region R that utilizes strain, defects, and the like at the interface.

[0024] The recombination region R described above may be an active recombination region R using a force pn junction or a Schottky junction as in the passive recombination region R. For example, similarly to the collector region C, an n-type recombination region R is formed in the p-type base region B, and a reverse bias voltage is applied to the ohmic electrode formed in the base region B. Then, the minority carrier electrons flowing into the recombination region R recombine with the majority carrier holes in the base region B. At this time, there is an advantage that it is possible to control the amount of minority carriers flowing into the recombination region R by the magnitude of the reverse bias voltage, that is, to control the recombination rate of minority carriers. Of course, the applied voltage may be zero.

[0025] In the above example, when single crystal GaAs is used, which can easily use a compound semiconductor such as GaAs, for example, silicon as the semiconductor, the mobility of electrons is large. it can.

[0026] The semiconductor magnetic sensor according to claim 2 of the present invention is a case where the S BI layer of the S〇I substrate is used as the region B. In particular, a silicon single crystal thin film layer formed on an insulator is used. If Since the technology of today's mature semiconductor integration (IC technology) can be used, a high-precision ultra-compact semiconductor magnetic sensor that is inexpensive, uniform, and mass-produced can be formed. The advantage is that peripheral circuits such as the sensor drive circuit, amplifier circuit and various compensation circuits can be integrated on the same substrate.

[0027] As an S〇I substrate, a silicon oxide film formed on a silicon single crystal substrate and a silicon single crystal semiconductor thin film layer formed thereon may be used. A substrate obtained by growing a single-crystal semiconductor thin film layer of epitaxy silicon on a sapphire substrate, which is an insulating substrate having a constant constant, may be used.

Further, in the single crystal semiconductor thin film layer, a part or all of the single crystal semiconductor thin film layer other than the part where the transistor is formed is etched away, and the region B flowing from the region E to the region C via the region B (the base region B By passing the minority carrier to the region having magnetic sensitivity only in the region having magnetic sensitivity, almost no current flows through the region having no magnetic sensitivity, so that a high-sensitivity magnetic sensor can be provided.

The semiconductor magnetic sensor according to claim 3 of the present invention is a case where the recombination region R is electrically connected to the region B and has a conductivity type different from that of the region B. If the region B is p-type, an n-type region is formed by adding impurities to form a pn junction with the region B, or if a MOSFET type, a voltage is applied to the gate. Then, an inversion layer that becomes an n-type region is formed at the MOS interface so that these c region and p-type region B are electrically short-circuited or a voltage is applied to promote recombination. You may do it. When a voltage is applied, the recombination ratio of injected electrons, which are minority carriers, can be adjusted.

In the semiconductor magnetic sensor of the present invention, the recombination of the minority carriers injected into the base region during the diffusion is used during the operation of the transistor, so that the base region has almost no drift electric field. Even if an n-type region is created as the recombination region R, the electric field distribution does not become complicated unlike the case where the drift electric field of the conventional double injection pin magnetic diode is generated. . Therefore, this n-type region effectively works as a recombination region R.

The semiconductor magnetic sensor according to claim 4 of the present invention is a case where a plurality of regions C are provided for one region E. In the detection of a two-dimensional or three-dimensional external magnetic field H and the formation of a pair of semiconductor magnetic sensors, a plurality of regions C are arranged for one region E. There is an advantage that the size is small and the number of electrodes is small.

A semiconductor magnetic sensor according to claim 5 of the present invention is a case where a plurality of units of a semiconductor magnetic sensor having a region E, a region B, a region C, and a recombination region R are provided on the same substrate. Measurement of the magnetic field distribution and detection of the two-dimensional or three-dimensional external magnetic field H are advantageous because they can be miniaturized.

[0033] The semiconductor magnetic sensor according to claim 6 of the present invention is a case where two units are formed as a pair, and the output of the pair is differentially amplified. It is suitable for temperature correction and for increasing the output by connecting two units in opposite directions.

[0034] The semiconductor magnetic sensor according to claim 7 of the present invention is a case where a unit is arranged so that a two-dimensional or three-dimensional external magnetic field H can be measured. The two-dimensional measurement of the external magnetic field H is achieved by arranging units on the same semiconductor substrate at right angles on a plane, but the three-dimensional external magnetic field H is measured with respect to the orthogonal arrangement on a two-dimensional plane. It is better to arrange them further orthogonally, or to arrange the three units so that they have orthogonal components to each other.

[0035] The semiconductor magnetic sensor according to claim 8 of the present invention is an integrated circuit together with other circuits on the same substrate, and includes a drive circuit, an amplifier circuit, various compensation circuits, an operation circuit, The semiconductor magnetic sensor of the present invention is integrated with peripheral circuits of the semiconductor magnetic sensor and an integrated circuit for other purposes, such as a memory circuit and a display circuit for displaying outputs and the like.

The manufacturing process of the semiconductor magnetic sensor of the present invention is compatible with the CMOS process. Therefore, by integrating the semiconductor magnetic sensor with another integrated circuit on one chip, it is possible to reduce the length of the lead wires and the like. In addition to providing low-noise, high-sensitivity, high-performance semiconductor magnetic sensors, other sensors such as temperature sensors, humidity sensors, and optical sensors, as well as integration of drive circuits required for those sensors, etc. In the case of manufacturing a multifunctional sensor device by integrating with a circuit, there is an advantage that a smaller and more compact device can be provided because the device can be integrated on one chip.

In the semiconductor magnetic sensor according to claim 9 of the present invention, a yoke made of a ferromagnetic film is formed on the substrate on which the semiconductor magnetic sensor is formed, and the magnetically responsive portion of the semiconductor magnetic sensor is formed. In this case, the intensity of the external magnetic field is increased. The larger the magnetic permeability of the ferromagnetic film, the better and the smaller the coercive force. After depositing a ferromagnetic film by sputtering or the like, patterning and attaching a ferromagnetic film that can be used as a yoke, etc., and then patterning to form a ferromagnetic film of appropriate shape It is preferable to form a pair of yokes so that the magnetically sensitive portion of the semiconductor magnetic sensor is located at the gap between them. Since the ratio of the gap length to the length of the yoke of the ferromagnetic film greatly contributes to the magnetic flux convergence ratio, in order to increase the magnetic sensitivity, the magnetic sensitive portion of the semiconductor magnetic sensor is made as small as possible, and the gap length is reduced. Care should be taken to make it as small as possible.

When the yoke greatly contributes to the magnetic sensitivity, the yoke is formed on the same plane by bending the yoke three-dimensionally along the plane perpendicular to the substrate to guide the magnetic flux along the plane. It is also possible to measure a two-dimensional or three-dimensional external magnetic field H even in a magnetically sensitive part of a semiconductor magnetic sensor. When a pair of yokes cannot be formed, only one of the yokes may be formed, and the magnetic sensitive portion of the semiconductor magnetic sensor may be arranged at the tip.

In the semiconductor magnetic sensor according to claim 10 of the present invention, a conductor is disposed at a position of a magnetically responsive part or at a position separated by a predetermined distance from a tip of a yoke, and a current is caused to flow through this conductor, This is the case where the external magnetic field H is calibrated using the magnetic field due to the current.

[0040] Semiconductor magnetic sensors have temperature dependence and changes over time, and when these are used as measuring instruments, these changes need to be corrected. Calibration is performed every time after measurement, or calibration is sometimes performed. There is a need to. When a current is passed through the conductor, a magnetic field is generated around it, and the magnetic field due to the current flowing through the conductor at a predetermined distance from the magnetically sensitive part of the semiconductor magnetic sensor can be calculated.Therefore, pulse current, AC current, DC current, etc. Is passed through the conductor to calibrate the semiconductor magnetic sensor.

[0041] The conductor may be a straight line or a coil, or may be formed of a thin-film conductor so as to cover the magnetically sensitive portion of the semiconductor magnetic sensor so that a uniform magnetic field acts on the magnetically sensitive portion. Talk about it.

If there is a yoke, it may be formed by a thin film conductor so as to surround the yoke one or several times with a coil via an insulating layer. Since there is also leakage magnetic flux, the yoke It is better to set it as a predetermined value of the distance from one end of the graph so that it is easy to fit in calculations with good reproducibility.

A magnetic measuring device using the semiconductor magnetic sensor of the present invention according to claim 11 of the present invention includes a power supply unit, a drive circuit unit of the semiconductor magnetic sensor, a calibration circuit unit of the semiconductor magnetic sensor, an output amplifier A magnetic measuring device having a circuit section including a circuit section, an arithmetic circuit section, and a display circuit section. The measurement of geomagnetism, the measurement of magnetic flux, the measurement of current, the measurement of direction, the magnetic flaw detection and its image display, the magnetic head It is a device that performs measurements such as magnetic recording and magnetic field measurement and displays the results.It can be equipped with a magnetic sensor that can be completely integrated into an IC, so it is inexpensive, low power consumption, and compact. .

The invention's effect

Since the present invention is configured as described above, it has the following effects.

[0045] In the semiconductor magnetic sensor of the present invention, the present invention is different from the above-described semiconductor magnetic sensor, which utilizes a current change based on deflection and recombination of a conventional double injection carrier of a semiconductor diode due to a magnetic field. Since the semiconductor magnetic sensor operates as a transistor that changes the recombination ratio of minority carriers in the base injected into the base by the external magnetic field H, the double injection phenomenon is not used. Minority carriers can be easily injected into the base by application, and force diffusion mainly occurs, and the current slowly flows toward the collector drain, which is the region C. As the carrier velocity becomes smaller, the interaction time with the external magnetic field H decreases. In contrast to the case of the drift velocity due to the strong electric field during double injection of a magnetic diode with a long There is an advantage but is achieved.

In addition, bipolar transistor type and MOSFET type semiconductor magnetic sensors can be provided. In particular, since the MOSFET type has a gate, a channel can be formed by inverting the base region at the MOS interface, or even the inversion can be achieved. The same operation as the bipolar transistor type can be performed in the absence of such a device, enabling fine control such as the adjustment of magnetic sensitivity and the dynamic range of magnetic measurement for the magnitude and direction of the external magnetic field H. It is.

[0047] In the conventional double injection type pin magnetic diode, double injection is performed in the recombination region R. Even when electrons and holes are bent by the external magnetic field H and are completely recombined, a recombination current flows, and the current change rate does not increase so much. Since the magnetic sensor is a transistor type, if the minority carriers are bent by the external magnetic field H and disappear by recombination in the recombination region R, the collector or drain current becomes almost zero and the rate of change of the current becomes large. There is an advantage that a large magnetic sensitivity can be obtained.

[0048] Since a pn junction or an inversion layer can be used as the recombination region R, a design can be made and a stable and stable recombination region R can be formed. Further, since the magnetic sensitivity can be made variable by adjusting the applied voltage to the region B, a magnetic sensor and a magnetic measuring device having a large dynamic range can be provided.

[0049] Since a main part such as a magnetically sensitive part of the semiconductor magnetic sensor can be formed in the SOI layer, it is possible to limit the flow path of the injected minority carrier to the recombination region R. This means that the majority of the injected minority carriers can effectively reach the recombination region R or be separated from the recombination region R by the Lorentz force due to the external magnetic field H, so that high magnetic sensitivity can be obtained. There is an advantage when it is done.

[0050] Magnetic circuits can also be integrated using CMOS-compatible microfabrication technology, so that various applications as magnetic sensors can be expected.

[0051] The latest integration technology of semiconductors can be used, ultra-small, low power consumption, high sensitivity with extremely little change over time, and drive circuits, amplifier circuits, various compensation circuits, etc. are integrated on the same substrate. In addition to providing a semiconductor magnetic sensor that can be used, an inexpensive, low power consumption, and compact magnetic measurement device is provided.

Brief Description of Drawings

[FIG. 1] FIG. 1 shows an embodiment of a semiconductor magnetic sensor, and is a schematic cross-sectional view of a main part of the sensor, in which the embodiment is implemented as an npn bipolar transistor type semiconductor magnetic sensor.

FIG. 2 is a bird's-eye view of the embodiment of the semiconductor magnetic sensor of the present invention shown in FIG. 1, and is a schematic diagram.

FIG. 3 is a schematic cross-sectional view of another embodiment showing the structure of the semiconductor magnetic sensor of the present invention, which is of a MOSFET type. FIG. 4 is a schematic cross-sectional view of another embodiment showing the structure of the semiconductor magnetic sensor, in which a gate electrode 512 is partially formed.

Garden 5] FIG. 5 is a schematic plan view of the semiconductor magnetic sensor of the present invention shown in FIG.

Garden 6] FIG. 6 is a schematic plan view of another embodiment showing the structure of the semiconductor magnetic sensor of the present invention, in which a pn junction is used in the recombination region R.

Garden 7] FIG. 7 is a schematic view of another embodiment showing a structure using a pn junction in a recombination region R of a semiconductor magnetic sensor.

Garden 8] FIG. 8 is a schematic view of another embodiment showing a structure using a pn junction in a recombination region R of a semiconductor magnetic sensor.

FIG. 9 is a schematic view of another embodiment showing the structure of the semiconductor magnetic sensor, in which two regions C are provided for one region E.

FIG. 10 is a schematic plan view of another embodiment showing the structure of the semiconductor magnetic sensor, in which a yoke made of a pair of ferromagnetic materials is formed.

FIG. 11 is a schematic plan view of another embodiment showing the structure of the semiconductor magnetic sensor, in which a yoke suitable for a magnetic head is formed.

Garden 12] FIG. 12 is a schematic plan view of another embodiment showing the structure of a semiconductor magnetic sensor, in which a current It is passed through a conducting wire so that a magnetic field can be calibrated.

Garden 13] FIG. 13 is a block diagram showing various circuit sections as components of the magnetic measurement apparatus of the present invention and the flow of the electric signal system.

Explanation of symbols

1 substrate

3 Inversion layer

4 Channel section

5 Non-recombination region

10 SOI layer

11 Base substrate

20 n-type layer 50 Electrical insulator

51, 52 Insulating thin film

60 Etch removal area

61 Isolation area

101 Emmitta

102 base

103 Collector

111 source

112 gate

113 Drain

114 Channenore

300 magnetic circuit

310, 310a, 310b Yoke

320 back yoke

330 Magnetic Head Tip

350, 351 gap

411, 412, 413, 414 Contact Hall

500 electrodes

501 emitter electrode

502 Base electrode

503 Collector electrode

511 source electrode

512 Gate electrode

513 Drain electrode

514 recombination electrode

600 conductor

BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the semiconductor magnetic sensor of the present invention will be described in detail with reference to the drawings. To do.

Example 1

FIG. 1 shows an embodiment of a semiconductor magnetic sensor of the present invention, and is a schematic cross-sectional view of a main part of the sensor. The embodiment is implemented as an npn-type bipolar transistor-type semiconductor magnetic sensor, and has a region as a base 102. This is a case where a recombination region R is provided in B. The figure shows the emitter terminal E, the base terminal B, and the collector terminal C, and the oxide film and electrodes on the surface are omitted for simplicity.

The operation of the semiconductor magnetic sensor of this embodiment will be described as follows.

As a substrate 1, a 1 μm-thick insulating layer of an electrical insulator 50 serving as a silicon oxide film is formed on an SOI substrate (for example, an underlying substrate 11 of p-type silicon (Si), and a single-crystal semiconductor Using a SOI layer 10 as a thin film layer with a thickness of 5 / m), a p-type semiconductor (hereinafter referred to as p-type in the present specification) of one conductivity type as the region B and the other A region E and a region C of an n-type semiconductor (hereinafter, referred to as n-type in the present specification) having the conductivity type are formed close to the SOI layer 10, and the SOI layer 10 around the region E is removed by etching. The etching removal portion 60 is formed. This is because the minority carriers injected from the region E into the region B flow only near the recombination region G, which is the magnetically sensitive portion, and reach the region C, thereby increasing the magnetic sensitivity.

On the surface (one surface) of region B, for example, argon gas and a small amount of oxygen gas are flowed while sputtering with ions of these gases to form defects on the surface, and recombination region R To form a recombination region R whose surface is stabilized by forming a surface, chemically roughening the surface using a solution, etc., or combining physical sputtering defects and a chemical reaction by chemical treatment. You may. Alternatively, a recombination region R for promoting recombination of carriers may be formed by adding gold, platinum, or the like by an ion implantation method or a diffusion technique to act as a killer center. Since the SOI layer is silicon, the oxide film becomes an extremely stable Si〇 film, and a stable recombination region R with very little change over time can be formed.

Further, in the present embodiment, an SOI substrate is used as the substrate 1, and a thermal oxide film of silicon is stably formed on the back surface side of the recombination region R formed in the region B of the SOI layer 10. Thus, a non-recombination region 5 is obtained. [0059] These structures shown in Fig. 1 of this embodiment constitute a lateral npn-type bipolar transistor. Region E corresponds to emitter 101, region B corresponds to base 102, and region C corresponds to collector 103, respectively. ing. When a forward bias voltage Vb is applied to the emitter 101 and the base 102, a small number of carriers are injected into the base 102 from the n-type emitter 101 and the p-type base 102. The collector 103, which is reverse-biased with respect to the base 102, is placed close to the base 102 through the applied voltage Vc of the emitter 101 and the collector 103, so that the collector 103 is swept out and the collector current Ic Mainly observed as output voltage across load resistance RL connected to collector 103

As shown in FIG. 1, when the minority carrier electrons injected from the emitter 101 into the base 102 are bent toward the recombination region R by the Lorentz force due to the external magnetic field H, the positive carriers that are the majority carriers of the base 102 The holes also gather to maintain electrical neutrality, and these electrons and holes recombine in the recombination region R. The holes lost at this time are supplied through the base electrode 502 provided on the base 102 and become a base current. The electrons injected at this time are severely lost by recombination, and when the number reaching the collector 103 becomes extremely small, the collector current Ic flowing through the reverse-biased collector 103 becomes extremely small.

[0061] In a conventional semiconductor magnetic sensor using a double injection type diode, a recombination current flows through the diode even if the double injected electrons and holes are recombined, and the current value is saturated. On the other hand, the transistor-type semiconductor magnetic sensor of the present invention utilizes only the flow of minority carriers. Therefore, when the injected minority carriers are lost due to recombination, almost all of the collector current is reduced. Since Ic stops flowing, a change in collector current Ic due to a large external magnetic field H can be obtained, so that a large magnetic sensitivity can be obtained.

When the minority carrier electrons injected from the emitter 101 are applied in a direction opposite to the direction of the external magnetic field H shown in FIG. 1, the electrons are bent toward the non-recombination region 5 and recombination is prevented. Very few injected minority carrier electrons reach the collector 103, resulting in a large collector current Ic.

[0063] When the external magnetic field H is not applied, it depends on the thickness and length of the base 102 and the recombination region R, and the degree of recombination of the recombination region R. Many of the minority carrier electrons are recombined in the recombination region R during diffusion, and the number of electrons that can reach the collector 103 is reduced. Therefore, the structure is such that the collector current Ic does not easily flow as compared with the device without the recombination region R.

In the semiconductor magnetic sensor of the present invention, when the minority carriers injected into the base 102 are bent toward the recombination region R depending on the direction of application of the external magnetic field H, the collector current Ic is reduced when the external magnetic field H is absent. When it is bent toward the non-recombination region 5, the collector current Ic becomes larger than when there is no external magnetic field H, and the degree depends on the magnitude of the external magnetic field H. It becomes a magnetic sensor whose size and direction can be determined.

An outline of an example of a manufacturing process in an element portion of the semiconductor magnetic sensor of the present invention will be described. First, as a substrate 1, a 1 μm-thick thin film layer of an electrical insulator 50 made of a silicon oxide film is formed on a base substrate 11 of about 500 × m thickness of p-type silicon (Si). An SOI substrate on which a p-type SOI layer 10 of about lcm is formed is used. This SOI substrate is thermally oxidized to form a 0.5 μΐη thick insulating thin film 51 with SiO force on the entire surface.

2

Used as a diffusion mask. Thereafter, the region of the p-type SOI layer 10 in which the regions E, B, and C are formed is left in the form of an island, and the periphery thereof is circled, and the insulating thin film 51 and the SOI layer on the surface are formed by known photolithography. The layer 10 is removed by etching to form an etched portion 60.

In general, the minority carriers in the base 102 as the region B in which the electron mobility is about three times larger than the hole mobility are such that the electrons can reach the collector 103 more easily. It is better to use layer 10.

The emitter 101 as the n-type region E and the collector 103 as the region C are separated by about 5 μm, and phosphorus (P), which is an n-type impurity, is formed by thermal diffusion or ion implantation. Next, of the base 102 as the region B, the pn junction force of each of the emitter 101 and the collector 103 is separated by about 1 μm, and the remaining area of about 3 μm of the base 102 area is defined as the recombination area R. For this purpose, after removing the entire thermal oxide film on the recombination region R by etching, sputtering is performed by adjusting the appropriate gas flow rate, power, and time in argon and a small amount of oxygen gas using a sputtering device. Then, defects are formed in the surface layer portion of this region to form a recombination region R. After that, when amorphous silicon is further deposited to form surface distortion, Both are used as surface protection films. After that, the contact horns 411, 412, 413, 414 are formed by ordinary photolithography. Do.

FIG. 2 shows the application of the semiconductor magnetic sensor of the present invention shown in FIG. 1 of the first embodiment to a magnetic head in consideration of the application of the base 102, which is a magnetic sensing part, to the end of the silicon chip of the substrate 1. FIG. 3 is a schematic view of a bird's eye view of an example in which a connection region R is formed. The figure shows an emitter terminal E, a base terminal B, and a collector terminal C, and other electrical circuits and the like are omitted.

Example 2

FIG. 3 is a schematic cross-sectional view of another embodiment showing the structure of the semiconductor magnetic sensor of the present invention, which is almost the same as the structure shown in FIGS. 1 and 2 of the first embodiment. One major difference is that the insulating thin film 51, which is a gate oxide film, is formed on the base 102 and the gate electrode 512 is formed, and the MOS interface of the p-type base 102 does not reach the n-type inversion. The gate voltage Vg is applied to the source 111, and it is essentially the same as the bipolar transistor type.However, since the MOS structure gate 112 is provided, it is named as the MOSFET type. It is. Therefore, the region E in FIG. 1 of the first embodiment is referred to as the source 111, and the region C is referred to as the drain 113.

[0070] By the forward voltage Vb applied between the source 111 and the base 102, electrons as a minority carrier are injected into the base 112. The injected minority carriers are likely to occur on the MOS interface side corresponding to the channel 114 immediately below the gate electrode 512. Actually, the gate voltage V g is an appropriate voltage applied so that the n-type inversion layer 3 is not formed at the MOS interface of the base 102, so that the channel 114 is not formed. 〇S It is easy to gather at the interface.

The minority carrier electrons injected into the base 102 are bent in the direction of the recombination region R by Lorentz force depending on the direction and magnitude of the external magnetic field H in the same manner as in the first embodiment, and are recombined. As a result, it is impossible to reach the drain 113 as the region C, and the drain current Id hardly flows, or depending on the direction and magnitude of the reverse external magnetic field, it is bent to the non-recombination region 5 side and reaches the drain 113 As the number of electrons increases, a relatively large drain current Id flows. In this case, the output is also easily connected to the load resistor connected to the drain terminal D. It can be extracted as an anti-RL voltage drop.

[0072] It is also possible to open the base terminal B. In this case, the injection of minority carrier electrons from the source 111 to the base 102, which acts as a pure MOSFET, is reduced. It is better to apply a forward voltage Vb to the junction to promote minority carrier injection.

Example 3

FIG. 4 is a schematic cross-sectional view of another embodiment showing the structure of the semiconductor magnetic sensor of the present invention. The force is almost the same as the structure shown in FIG. The difference is that the gate electrode 512 is partially formed in the middle between the source 111 and the drain 113, and the gate electrode 512 is formed on the gate electrode 512. A relatively large voltage Vg is applied, and Vg is appropriately applied to the source 111 so that the n-type inversion layer 3 is formed at the MOS interface of the p-type base 102. A recombination terminal R that is electrically connected to the inversion layer 3 is formed via the n-type layer 20 formed in 102, and a recombination promoting voltage Vr is applied between the recombination terminal R and the base terminal B. This inversion layer 3 is used as a recombination region R. In this case, the thickness of the sensor 113 reaches the bottom of the S 10I layer 10 serving as the base 102 as the region B. , The drain 113, the base 102 region under the gate electrode 512 and the region of the n-type layer 20 are left in an island shape, and the periphery thereof is formed in the SOI layer 10 as an insulating isolation region 61. In this case, the minority carriers injected from the source 111 into the base are confined in the main part of these island-like components of the sensor, so that the injected electrons can be used. The main difference is that it does not flow out of the area. Note that the insulating isolation region 61 is a layer which is formed as an electrical insulating layer by ion implantation of oxygen or the like or partial thermal oxidation, or a high-concentration p-type layer to prevent electrons as injected minority carriers. But it's fine.

FIG. 5 shows a schematic plan view of the semiconductor magnetic sensor of the present invention shown in FIG. In FIG. 5, the power supply unit and the like are omitted. The insulating thin film 52 on the surface, which is omitted in FIG. 4, is shown. Example 4

FIG. 6 is a schematic plan view of another embodiment showing the structure of the semiconductor magnetic sensor of the present invention, and is substantially the same as the structure shown in FIGS. 1 and 2 of the first embodiment. The first difference is that the n-type layer 20 formed near the surface of the base 102 is used as the recombination region R. To make the recombination region R effective, the conductive recombination terminal R of the n-type layer 20 and the base terminal B are short-circuited, or as described in the embodiment in FIGS. 4 and 5. Then, a recombination promoting voltage Vr may be applied. Second, the recombination region R does not completely block the path of the base 102 through which the injected minority carrier electrons flowing from the emitter 101 to the collector 103 pass through the n-type layer 20 as the recombination region R. 4, the direction of application of the external magnetic field H is also prosperous, and is applied perpendicularly to the SOI layer 10 having the layer of the base 102. The point that the SOI layer 10 is formed as the insulating isolation region 61 described above so that the SOI layer 10 can be used while being flat.

The n-type layer 20 may reach not only near the surface of the base 102 but also completely to the insulating thin film 51 below the surface of the SOI layer 10.

Example 5

FIG. 7 is a schematic diagram of another embodiment showing the structure of the semiconductor magnetic sensor of the present invention, which is similar to the semiconductor magnetic sensor shown in FIG. As the recombination region R, the n-type layer 20 formed near the surface of the base 102 is formed so as to cross and cover the width of the base 102, so that electrons injected from the emitter 101 reach the collector 103. In this case, the application direction of the external magnetic field H is parallel to the layer of the base 102 in that the layer passes under the recombination region R of the base 102. FIG. 7 shows a case where a recombination promoting voltage Vr is applied to the base terminal B and the recombination terminal R. The width of the depletion layer changes due to the reverse bias of the pn junction between the recombination region R composed of the n-type layer 20 and the p-type base 102 by adjusting the applied voltage of the recombination promoting voltage Vr. The width of the path changes and the recombination rate can be adjusted. Of course, if the recombination promoting voltage Vr is set to zero, the base terminal B and the recombination terminal R are short-circuited. FIG. 8 shows that, in the embodiment shown in FIG. 7, instead of externally short-circuiting the base terminal B and the recombination terminal R to the base electrode 502 of the embodiment shown in FIG. An embodiment in which the coupling electrode 514 is combined with one electrode is shown. In this case, of course, the recombination ratio of electrons injected into the base 102 cannot be adjusted, but there is an advantage that the structure becomes compact.

Example 6

FIG. 9 is a schematic view of another embodiment showing the structure of the semiconductor magnetic sensor of the present invention. The structure shown in FIG. In this case, collectors CI and C2 as two regions C are provided for the emitter 101 as one region E. In this case, only one base electrode 502 is required. The two paired recombination regions R are arranged on the same side of the base 102, so that the collector current of one of the semiconductor magnetic sensors increases with respect to the external magnetic field H from the same direction. However, since the other collector current is smaller, these differential outputs have the advantage that they are almost twice as sensitive as a single force due to the variation in the characteristics of the paired semiconductor magnetic sensors. Also, by using differential amplification, the noise common to both is almost canceled, and the output when the external magnetic field H is zero can be made zero, so that there is an advantage that a high sensitivity semiconductor magnetic sensor with a large SN ratio can be obtained. is there.

Example 7

FIG. 10 is a schematic plan view of another embodiment showing the structure of the semiconductor magnetic sensor of the present invention. In the recombination region R of the bipolar transistor type semiconductor magnetic sensor, a magnetic field is shown. This figure shows a case in which the yokes 310a and 310b formed of a pair of elongated thin film-like ferromagnetic materials for converging magnetic flux as the air circuit 300 are arranged such that the gap 350 is positioned. With such a structure, it is possible to effectively guide the magnetic flux at a remote location to the recombination region R, which is the magnetically responsive part of the semiconductor magnetic sensor.

[0081] In Fig. 9 of this embodiment, a pair of yokes 310a and 310b are shown, and only one yoke has an effect of converging magnetic flux. If the shape effect of these yokes 320 is required to be great, it is appropriate to appropriately design the thickness, the length, the interval of the gap 350 in the case of a pair, and the magnetic flux convergence by sharpening the tip. Example 8

FIG. 11 is a schematic plan view of another embodiment showing the structure of the semiconductor magnetic sensor according to the present invention. As in the case of the seventh embodiment, the semiconductor magnetic sensor of the bipolar transistor type is used again. This is the case where the gap is formed between the yokes 310a and 310b on the surface of a pair of thin and thin ferromagnetic materials that converge the magnetic flux as the magnetic circuit 300 in the coupling region R. The major difference is that, as the magnetic circuit 300, one yoke 310a is also extended on the back surface of the substrate 1 to form a back yoke 320, and the yoke 310b on the other surface is substantially equal to the thickness of the substrate 1 There is one gap 351, and the gap 351 and the sharpened magnetic head tip 330 of the yoke 310 b make a magnetic head for reading suitable for detecting a magnetic field from an extremely weak and minute magnetic domain, particularly a vertical magnetic head. The point is that the structure is suitable for reading magnetic recording.

Although not shown here, the ferromagnetic yoke 310 may be formed only on the side of the substrate 10 where the recombination region R, which is the magnetically responsive part, is formed.

Example 9

FIG. 12 is a schematic plan view of another embodiment showing the structure of the semiconductor magnetic sensor of the present invention. In the case of a semiconductor transistor of a non-polar transistor type, for example, Above the recombination region R, which is a magnetically sensitive part, so that the current It flows in the direction along the base 102 toward the direction of the collector 103 as the region C and toward the emitter 101 as the region E, A thin conductive wire 600 is formed in close contact with an insulating layer and patterned, and a predetermined current It is applied to the electrode terminals Tl and T2 of the conductive wire 600. This is a case where the magnetic sensor is calibrated.

[0085] Calibration can be performed by passing a pulse-like current It or a current It of various magnitudes through the thin-film conductive wire 600. In addition, calibration can be performed by changing the direction of the current It.

Example 10

FIG. 13 is a block diagram showing various circuit units constituting components of the magnetic measurement apparatus of the present invention equipped with the semiconductor magnetic sensor of the present invention and the flow of the electric signal system. Since the semiconductor magnetic sensor of the present invention is completely compatible with the CMOS process, a drive circuit of the semiconductor magnetic sensor as various circuit units, which are the components in the thick frame, in the magnetic measurement device indicated by the broken line Most of the semiconductor circuit, the calibration circuit, the output amplifier circuit, the arithmetic circuit, and the display circuit of the semiconductor magnetic sensor can be monolithically formed on the same substrate as the magnetic transistor, which is the magnetic detector of the semiconductor magnetic sensor. .

Except for the external power supply unit, switch, display unit, and the like, most of the circuit units can be easily integrated on the same substrate as the semiconductor magnetic sensor, and the power can be mass-produced. It is possible to provide a simple magnetic measurement device.

[0089] The above embodiment is merely an embodiment of the present invention, and it is apparent that there are many modifications of the present invention while the gist, operation, and effects of the present invention are the same.

Industrial applicability

As described above, the semiconductor magnetic sensor according to the present invention and the magnetic measurement device using the same can determine the direction of the terrestrial magnetism, which is the direction of the magnetic field, and can be easily and easily used by using a bipolar transistor type semiconductor magnetic sensor. It is useful for magnetic measurement devices, especially suitable for semiconductor magnetic sensors for azimuth sensors and magnetic heads for reproducing perpendicular magnetic recording, and for magnetic measurement devices, portable Gauss meters, ammeters and geomagnetic measurements for position display. Suitable for equipment

Claims

The scope of the claims

[1] One conductivity type region B of the semiconductor, the other conductivity type region E into which minority carriers are injected, and a region which is made of the same conductivity type or metal as this region E and receives the injected minority carriers. C are disposed in close proximity to each other, and a region B between the region E and the region C is provided with a recombination region R for recombining the injected minority carriers. The recombination region R is arranged so that the minority carriers injected into the region B are deflected by the Lorentz force and recombined at the recombination region R when the heat is applied. The number of the injected minority carriers reaching the region C is changed by the external magnetic field H, and information on the external magnetic field H is obtained from a change in the current flowing through the region C due to the change in the number of the minority carriers. A semiconductor magnetic sensor characterized in that:

[2] The semiconductor magnetic sensor according to claim 1, wherein an SOI layer is used as the region B.

3. The semiconductor magnetic sensor according to claim 1, wherein the recombination region R is a region that is electrically conductive with the region B and has a conductivity type different from that of the region B.

[4] The semiconductor magnetic sensor according to any one of claims 1 to 3, wherein a plurality of regions C are arranged for one region E.

[5] The semiconductor magnetic sensor according to any one of claims 1 to 4, wherein a plurality of semiconductor magnetic sensor units each having a region E, a region B, a region C, and a recombination region R are provided on the same substrate.

[6] The semiconductor magnetic sensor according to claim 5, wherein the two units are formed as a pair, and the output of the pair is differentially amplified.

7. The semiconductor magnetic sensor according to claim 5, wherein the unit is arranged so that a two-dimensional or three-dimensional external magnetic field H can be measured.

[8] The semiconductor magnetic sensor according to any one of claims 1 to 7, wherein the semiconductor magnetic sensor is integrated with other circuits on the same substrate.

[9] The yoke made of a ferromagnetic film is formed on the substrate on which the semiconductor magnetic sensor is formed so that the strength of the magnetic field in the magnetically sensitive portion of the semiconductor magnetic sensor is increased. The semiconductor magnetic sensor according to any one of claims 1 to 4.

[10] A conductor is placed at the position of the magnetically sensitive part or at a predetermined distance from the tip of the yoke, a current is passed through this conductor, and the external magnetic field H is calibrated using the magnetic field generated by the current. The semiconductor magnetic sensor according to any one of claims 1 to 9, wherein:

A power supply unit, a drive circuit unit of the semiconductor magnetic sensor, a calibration circuit unit of the semiconductor magnetic sensor, an output amplifying circuit unit, an arithmetic circuit unit, and a power supply unit. A magnetic measuring device comprising a circuit unit including a display circuit unit.