JP3133102B2 - Semiconductor magnetoresistive element - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor magnetoresistive element whose resistance changes depending on the strength of a magnetic field. In more detail, utilizing the principle that the current flowing through the pn junction increases and decreases the resistance value due to the Hall voltage generated by passing the current in parallel to the pn junction, the magnetic sensor and the magnetic field for reading magnetic data are used. The present invention relates to a semiconductor magnetoresistive element serving as a head.

[0002]

2. Description of the Related Art The magnetoresistance effect is well known as a phenomenon in which the electric resistance changes when a magnetic field is applied to a semiconductor. When a current is applied to the semiconductor in a direction perpendicular to the magnetic flux, the majority carrier tends to bend due to Lorentz force. However, in general, a large number of carriers do not bend because a hole voltage is generated by carriers that are bent and gathered on the surface to maintain equilibrium.

If the velocity of the majority carrier has a distribution, the Hall voltage does not completely cancel the Lorentz force, and the trajectory of the majority carrier is changed by the magnetic flux. Therefore, the moving distance of the majority carrier in the semiconductor becomes long,
The resistance increases because the number of collisions with impurity ions and lattice increases. The effect when the magnetic flux and the current are applied at right angles is particularly called a transverse magnetoresistance effect.

In a conventional magnetoresistive element using a semiconductor, a rough surface is provided on the surface of an i-layer of a pin diode by sandblasting or the like, and each minority carrier double-injected into the i-layer is roughened by a magnetic field. Some are based on the principle that recombination is promoted when the surface is bent.

[0005] In the double injection state, since the Hall voltage is hardly generated, the deflection of the carrier is large.

In this type, the front and back surfaces of the i-layer are made rough and smooth, respectively, so that the magnetic resistance changes according to the direction of the magnetic field, and is called a magnetic diode.

As another magnetoresistive element using a semiconductor, a corbino disk has been known for a long time. In this method, electrodes are provided at the center and the periphery of a disk-shaped semiconductor so that a Hall voltage is not generated skillfully.

As another example, there is an MR element utilizing a change in electric resistance due to a domain wall of a soft magnetic metal thin film, and is used as a magnetic head for reading magnetic data.

[0009]

The phenomenon in which the carrier voltage is prevented from being deflected by the Hall voltage always appears in a type utilizing a large number of carriers of a single conductivity type semiconductor, such as a Hall element, and is an essential problem. . This is a serious problem, especially when the principle is based on the deflection of majority carriers. For this reason, efforts have been made to reduce the adverse effect of the Hall voltage on the principle of carrier deflection.

In the conventional pin diode in which one surface of the i layer is sandblasted to eliminate the effect of the Hall voltage, recombination on the rough surface side of the i layer is based on the principle. It is difficult to make things.

[0011] In addition, a treatment such as sand blasting is required, and it is not suitable for fine processing because of its large shape.

Further, since the device operates by diffusion of the double-injected minority carriers in the i-layer, the response to a change in the magnetic field is slow, and the i-layer must be long.

On the other hand, since the outer electrode of the Corbino disk must surround the center electrode, the magnetic field sensitive portion becomes large, and a magnetic sensor with high spatial resolution cannot be obtained.

Further, in the MR element, the change in resistance due to the magnetic field is 1% or less, the sensitivity is extremely small, and it is necessary to form a domain wall in advance. Therefore, a means for generating a DC magnetic field is required. Although the magnetic field can be detected in a minute space region at the tip of the head, there is a problem that peripheral elements such as a permanent magnet and a coil for generating a DC magnetic field are required.

[0015]

In order to solve the problems described above, a semiconductor magnetoresistive element according to the present invention comprises a pn junction formed between a first conductive type layer and a second conductive type layer of a semiconductor on a substrate. Alternatively, a pin junction having an intrinsic semiconductor layer interposed therebetween is formed, and at least one of the two conductivity type layers is flowed with a large number of carriers in a direction parallel to the plane of the pn junction or the pin junction. Or, a configuration is adopted in which a forward bias voltage is applied to the pin junction, and the pn
Magnetic field applied in a direction parallel to the plane of the junction or pin junction
Before moving in a direction having a component orthogonal to the magnetic field
The change in the magnetic field is detected by the change in the current of the majority carrier.
Put out .

[0016]

According to the semiconductor magnetoresistive element of the present invention, a pn junction or a pin junction composed of a first conductivity type layer (n-type layer) and a second conductivity type layer (p-type layer) is formed on a substrate. A forward bias voltage is applied to the junction, and the p-type layer and the n-type layer are formed so that the majority carriers move parallel to the junction surface in a magnetic field. The carrier is lost by recombination at the junction, and the carrier is deflected again to compensate for it, and the Hall voltage increases. This has the effect of further increasing the carrier deflection and increasing the current across the junction.

In addition, the depletion layer of the pn junction or the intrinsic nature of the pin junction
The layers act to separate and flow the majority carriers of the p-type layer and the n-type layer when there is no magnetic field, and when a magnetic field is applied, the Hall voltage is superimposed on the forward bias voltage, and the forward voltage increases, Serves as an area where carrier recombination is high.

Further, a recombination center is formed by implanting heavy metal ions into the pn junction, which acts to promote the recombination of carriers in the depletion layer.

Also, the built-in potential is reduced by forward biasing the junction. Due to the forward bias, even a small Hall voltage causes recombination in the depletion layer,
Alternatively, the current flowing through the junction increases due to the injection recombination into the layer of the opposite conductivity type, so that the magnetoresistance effect appears greatly.

An electric change with respect to a change in the magnetic field can be observed by a change in a current flowing in the p-type layer or the n-type layer in parallel with the junction. Therefore, by providing an external resistor between the electrodes at the ends of the p-type layer and the n-type layer, a current flowing parallel to the junction surface is converted into a voltage, and the junction is forward-biased, and a voltage that is changed by a magnetic field is changed. Work as a monitor. Further, by providing an external diode between the electrodes at the ends of the p-type layer and the n-type layer, the junction functions to forward-bias at the rising voltage of the diode.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the semiconductor magnetoresistive element of the present invention will be described with reference to FIGS.

FIG. 1 is an explanatory view showing a planar structure of a semiconductor magnetoresistive element utilizing a semiconductor pn junction according to an embodiment of the present invention, FIG. 2 is a sectional view taken along the line AA, and FIG. It is explanatory drawing which shows the cross-section of another Example utilized.

1 and 2, reference numeral 11 denotes a p-type semiconductor substrate, and 12 denotes an n-type island formed by surrounding an n-type epitaxial layer formed on the semiconductor substrate 11 with a p-type diffusion layer 15. One conductive type layer (hereinafter, referred to as an n-type layer) is formed, and 13 is a second conductive type layer (hereinafter, referred to as a p-type layer) which is a p-type formed by impurity diffusion or the like in the first conductive type layer 12. ),14
Is a pn junction which is a boundary between the n-type layer 12 and the p-type layer 13. 16,
Reference numeral 17 denotes an n ⁺ -type high impurity diffusion layer formed by etching the protective film 18 to make ohmic contact with the electrodes 19 and 20, respectively, and reference numerals 19 to 22 denote the n-type layer 12 and the p-type layer 13 respectively.
Formed on the n-type layer 12 and the p-type layer 13 respectively.
Electrodes 23 and 24 are connected to the electrodes 19 and 20 and the electrodes 21 and 22 to flow a current in parallel with the surface of the substrate 14. , P-type layer
The current flowing through 13 is Ip. Reference numeral 25 denotes a forward bias constant voltage source for applying a forward bias voltage to the n-type layer 12 and the p-type layer 13. Wn and Wp represent the width of the n-type layer 12 and the p-type layer 13, respectively , tn and tp represent the depth thereof, and Ln and Lp represent the length between the electrodes of the n-type layer 12 and the p-type layer 13, respectively. FIG. 2 also shows the relationship between the direction of the magnetic field B (the crosses indicate the direction from the front to the back of the paper and the crosses indicate the reverse) and the direction of the force F to which electrons or holes are subjected.

[0024] In this configuration, a bias voltage is applied to the forward voltage V _F of the vicinity of the rising voltage of the junction to the pn junction 14, the In and Ip to flow in the opposite direction as shown in FIG. 2, the pn junction The majority carriers are separated by the depletion layer electric field generated in 14 and flow in parallel to the pn junction 14.
Here, when the magnetic field B is applied in the direction shown in the figure, the electrons 26 and holes 27, which are majority carriers, are caused by Lorentz force proportional to the vector product of the moving speed of the carrier and the magnetic flux density.
Each is bent so as to approach the pn junction 14. as a result
The density of electrons and holes on the pn junction 14 side increases, a hole voltage is generated, and the current across the pn junction 14 changes, indicating a change in resistance. The change in resistance also changes a direction transverse to the pn junction 14, but are example by measuring the current using a constant voltage source as the application of the bias voltage, to observe the phenomenon of current flowing parallel to the junction is changed You can also.

In FIG. 3, reference numerals 11 to 27 denote the same parts as in FIG. 2, reference numeral 28 denotes an intrinsic semiconductor layer (hereinafter referred to as an i-layer), 41
Reference numerals 43 to 43 denote n ⁺ -type buried layers formed on the junction surface between the p-type semiconductor substrate 11 and the n-type layer 12, and 47 denotes electrodes formed on the p-type layer 13 between the buried layer 41. It is connected to a forward bias constant voltage source 25 so as to be forward biased.

This configuration has a buried layer 41 on a p-type semiconductor substrate 11.
After implanting impurity ions in places where .about.43 are to be formed, an n-type layer 12 is formed by epitaxial growth. Then Similarly impurity grown semiconductor crystal not doped with d pin Takisharu deposition method i layer 28 is formed by,
The p-type layer 13 and the n ⁺ -type layers 16, 17 are formed by diffusion or ion implantation. Even in this structure, the pn junction 14
Only become a junction, i layer on behalf of the depletion layer of the above-mentioned
28 acts to separate the majority carriers, and the majority carriers flow parallel to the pin junction. When the magnetic field B is applied in the direction shown in FIG. 3, the majority carriers are bent so as to approach the i-layer 28, and the carriers deflected due to the Hall voltage being weighted by the forward bias voltage are recombined in the i-layer 28, and The current crossing the junction and the current flowing parallel to the pin junction change, and the resistance changes.

In these examples, an example in which an n-type layer and a p-type layer are formed on a semiconductor substrate has been described. However, instead of using a semiconductor substrate, an insulating substrate such as glass or ceramic is used. May be formed with an n-type layer or a p-type layer.

Next, how the resistance changes will be described with reference to FIGS. 4 to 9 using a band diagram, and the principle of the semiconductor magnetoresistive element of the present invention will be described in further detail.

FIG. 4 shows a band diagram when there is no magnetic flux, and FIG. 5 shows a band diagram when there is magnetic flux together with the voltage-current relationship. In the figure, 32 is an electron in the conduction band,
33 is a valence band hole, 34 is an n-type region, 35 is a p-type region, 36
Indicates a pn junction, and 37 (FIG. 8) indicates an i-layer. For convenience of explanation on the paper, the real space is shown by two-dimensional X and Z axes, and the direction axis of the magnetic flux and the direction axis of the energy of the electron are displayed in an overlapping manner. The directions of the axes are drawn in accordance with FIG. 1, and each axis is orthogonal to each other.

As shown in FIG. 4, when there is no magnetic flux, the Lorentz force does not work, so that electrons in the n-type and holes in the p-type, which are majority carriers, are separated by the electric field in the depletion layer of the pn junction. Only the current flows parallel to the pn junction.

When a magnetic flux is applied, a Lorentz force proportional to the vector product of the moving speed of the carrier and the magnetic flux density acts on many carriers. Due to this Lorentz force, the distribution of the majority carriers tends to temporarily increase in the direction in which the Lorentz force acts. In this state, as shown in FIG. 5, the density of the electrons 32 and the holes 33 increases on the pn junction side.

FIGS. 6 and 8 show a pn junction and
FIG. 7 shows a band diagram as viewed from the conduction band side to explain the movement of electrons in the case of a pin junction.
A band diagram viewed from the valence band side is shown to explain the movement of holes at the time of bonding. Here, FIG.
6 is a drawing exactly the same as FIG. 6, in which the perspective view is shifted to the lower side of the valence band. The directions of the space X and the current Ip are in the depth direction of the plane of the paper, and are drawn diagonally right below in the perspective view. All axes are orthogonal.

Here, since the directions of the currents flowing through the p-type region and the n-type region are opposite to each other, the directions in which the majority carriers move are the same. With proper selection of the direction of the magnetic flux, each majority carrier will tend to bend closer to the junction.

In practice, when there is a gradient in the density of a large number of carriers due to the Lorentz force, a Hall voltage is immediately generated. Since the force acting on the majority carrier due to the Hall voltage acts so as to balance the force acting on the majority carrier due to the Lorentz force, the majority carrier hardly bends in a steady state, and the Hall voltage appears in a direction orthogonal to the flow of the majority carrier. In the present invention, the Hall voltage is applied to the forward bias voltage, the carrier is lost by the recombination at the junction, and the carrier is again deflected by the amount to compensate for the loss. Even when a Hall voltage occurs, the magnetic field can be sensed as a change in current across the junction without hindering carrier deflection. In the conventional device based on the principle of carrier deflection, the Hall voltage has an adverse effect, but the present invention is characterized in that the Hall voltage is actively used.

FIG. 9 shows a band diagram of a cross section. A magnetic field is applied from below the paper surface, and a large number of carriers flow in the p-type and n-type regions in a direction penetrating the paper surface. Furthermore the pn junction by a constant voltage source, is forward biased near the rising voltage V _F of the junction.

The direction of the magnetic flux B is from bottom to top on the paper. In the p-type and n-type regions, a Hall voltage is generated in a direction perpendicular to the junction surface in each region. Assuming that the Hall voltage generated in the p-type region is ΔVp and the Hall voltage generated in the n-type region is ΔVn, the end of the semiconductor is a constant voltage source V _F
Therefore, the sum of the Hall voltage generated in the p region and the Hall voltage generated in the n region is applied to the junction in addition to the forward bias voltage. FIG. 9 shows a band diagram and a bias voltage by a solid line when a magnetic field is applied and by a dotted line when no magnetic field is applied.

As the voltage at the junction increases in the forward direction, some of the majority carriers flowing parallel to the junction will recombine in the depletion layer or i-layer, or will have a region of opposite conductivity type across the junction. Current either across the junction, either by recombination and recombination, or by diffusion to reach an electrode of the opposite conductivity type.

As a means for detecting a change in the current across the junction, the current value of the forward bias constant voltage source can be monitored by an ammeter or the like, or the junction potential can be monitored by a voltmeter or the like. . It can also be detected by monitoring the current flowing in parallel in the p-type layer or n-type layer without crossing the junction.

As described above, in the conventional magnetoresistive element, the generation of the Hall voltage acts in a direction that degrades the magnetic field sensitivity, and the deflection of a large number of carriers not balanced with the Hall electric field moving at a speed deviating from the average drift speed. Since recombination was the principle, the number of carriers involved in magnetoresistance was small and the magnetoresistance effect was small. However, in the semiconductor magnetoresistive element of the present invention, the Hall voltage works in the direction of increasing the magnetic field sensitivity, and the current across the junction surface changes greatly by the exponential function of the generated Hall voltage, so that the magnetoresistance effect is very large. large.

Further, the region where the carriers are recombined is in the bulk and is very stable without change over time.

In the semiconductor magnetoresistive element of the present invention, p
Assuming that currents flow in opposite directions in both the mold region and the n-type region, the Hall voltage generated in each region is as follows.

[0042]

(Equation 1)

[0043]

(Equation 2)

Here, V _Hn is the Hall voltage in the n-type region,
_Hp is the Hall voltage in the p-type region, W _n is the width of the n-type region, W
_p is the width of the p-type region, current I _n is the n-type region, I _p is the current of the p-type region, N is the carrier density of the n-type region, P is the carrier density of the p-type region, e is the elementary charge, B Indicates the magnetic flux density.

The current Id flowing through the junction is

[0046]

(Equation 3)

[0047] Here, _{I s} is the saturation current, k is the Boltzmann coefficient, T is the absolute temperature, V is showing a welding voltage.

When a large number of carriers flow in the semiconductor layer,
There is actually a resistor, and a voltage drop of the product of the resistor and the current occurs, and the forward bias is reduced.

This resistance R is

[0050]

(Equation 4)

Here, σ is the conductivity of the semiconductor layer, L is the length of the semiconductor layer, W is the width of the semiconductor layer, and t is the thickness of the semiconductor layer. Due to this resistance, a voltage drop distribution occurs along the length of the semiconductor layer, and the current across the junction is also a function of distance.

The ratio の between the Hall voltage V _H generated in the semiconductor layer and the product R · I of the resistance R of the semiconductor layer and the current I is

[0053]

(Equation 5)

Here, μ indicates the carrier mobility of the semiconductor. Since it is better that ξ is large, it is understood that a semiconductor material having a short and deep junction structure and a high mobility is preferably used in a general planar structure.

The Hall voltage is larger when the thickness W of the semiconductor in the direction in which the magnetic flux passes is smaller. However, since the electric resistance can be reduced when the cross-sectional area is large, it is preferable to increase the length t of another side constituting the cross-sectional area by an amount corresponding to the reduction of W from the restriction of the Hall voltage. t is the direction in which the Hall voltage is generated.

The current for generating the Hall voltage may be applied to only one of the n-type layer and the p-type layer. However, when the current is applied to both conductive layers in opposite directions, the magnetic field sensitivity is increased. This is because when current flows through only one conductivity type layer, only the Hall voltage generated in the conductivity type layer through which current flows can be used, but when current flows through both conductivity type layers. This is because the sum of the Hall voltages generated in both the conductive layers can be used.

In the actual manufacturing process, it may not be easy to make the impurity densities and shapes of the p-type layer and the n-type layer equal between different conductivity types. Should be optimized taking into account the voltage drop due to the above.

In the above embodiment, the carriers are recombined at the pn junction 14, but the n-type layer 12 and the p-type layer 13
It is preferable to form one or both of the layers in a low concentration layer because the inclination of the barrier becomes gentle and the recombination can be further facilitated. It is preferable that a high-resistance region such as an intrinsic semiconductor layer having a lower concentration is interposed between the n-type layer 12 and the p-type layer 13 because the effect is further promoted.

As another method of promoting recombination, a deep level of heavy metal ions such as gold or copper is provided at the bonding surface by ion implantation or diffusion, or a crystal defect is formed by ion implantation of argon or xenon. It is effective to provide a trap according to the above.

The current for generating the Hall voltage is represented by two constant current sources in the above description for convenience of explanation of the principle, but it is not necessary to be a constant current source in principle, and will be described later. As described above, the current passing through the first conductivity type layer may be introduced into the second conductivity type layer through a resistor or a diode or a Schottky diode. Hereinafter, the present invention will be described in further detail with still another embodiment.

FIGS. 10 and 11 show an embodiment of a semiconductor magnetoresistive element operated in a differential manner. That is, FIG. 10 is an explanatory diagram by a plan view, and FIG. 11 is an explanatory diagram by a BB cross section of FIG. In these figures, reference numerals 11 to 15, 18 to 22 denote the same parts as in FIG. 1, and reference numerals 41, 42, and 43 denote n ⁺ -type buried layers formed at the junction surface between the p-type semiconductor substrate 11 and the n-type epitaxial layer. Inclusive, 4
Reference numerals 4 and 45 denote n ⁺ -type diffusion layers connecting the electrodes 19 and 20 and the buried layers 42 and 43, and reference numeral 46 denotes an electrode formed on the n-type layer 12 and is connected to the buried layer 41 through the n ⁺ -type diffusion layer. ing. Reference numeral 47 denotes an electrode formed on the p-type layer 13, to which a forward bias voltage source 48 is connected so as to be forward biased with the electrode 46. A resistance R is provided between the electrodes 21 and 19 and between the electrodes 22 and 20.
_L, connects _{R R,} current _I L does not cross the pn junction by the forward bias voltage source, as _{I R} flows through the n-type layer 12 and p layer 13 _R L, the _{R R I} L, the _{I R} It is a means to detect.

[0062] In operation of this embodiment in the left area of FIG. 11, the product of the resistance R was if provided _L, current did not cross the street junction of p-type layer 13 I _L and the resistance R _L Voltage is generated. Although the magnitude of the resistance _RL depends on the resistance value of the p-type layer 13, the magnitude of the voltage at both ends of _RL is
Voltage V _F and the comparable 48, may be such that the voltage near threshold voltage of the junction.

The electric signal corresponding to the magnitude of the magnetism is represented by a resistance R
The difference of the voltage across the _L and R _R can be sold by monitoring. That is, as shown in FIG. 11, if magnetic flux passes from the front to the back of the paper, the direction on the left is a direction in which a large number of carriers pn are bent toward the junction 14,
The Hall voltage is added to the forward bias voltage, and the pn junction 14 is further biased in the forward direction.

On the other hand, on the right side, since the majority carriers bend in a direction away from the junction, the Hall voltage is in the opposite direction to the forward bias voltage, and the forward bias voltage is reduced by the Hall voltage. As a result, the current I _DL flowing across the pn junction 14 increases in the left region, and the pn region increases in the right region.
The current I _DL flowing across the junction 14 decreases.

Therefore, the voltage of the resistor _RL decreases and the voltage of _RR increases. By comparing the two with the differential amplifier 49, the change in the magnetic field can be accurately known.

FIGS. 12 and 13 show still another embodiment of the differential operation. That is, in this embodiment, the semiconductor portion is the same as that of the previous embodiment, and a diode D is used instead of the resistors R _L and R _R of the previous embodiment.
_L, connects the _{D R I} L, is obtained by the means for detecting the _{I R.}

[0067] Diode _D L, case in which the _{D R} is
Voltage across the diode, the diode D _L, may be substantially constant in the vicinity of the rising voltage of the D _R. Therefore, by detecting the currents A _L and A _R flowing through the diodes D _L and D _R and outputting the difference between them, the change in the magnetic field can be accurately known. This method is particularly effective when the resistance of the n-type layer 12 and the p-type layer 13 of the magnetoresistive element is relatively large.

FIG. 14 shows still another embodiment of the differential type magnetoresistive element. In the present embodiment, the periphery of the p-type layer 13 is surrounded by a thick oxide film 51 to eliminate a pn junction in a direction perpendicular to the substrate 11, thereby improving the S / N ratio. That is, if there is a joint on the side surface of the p-type layer, a Hall voltage is generated in the same axial direction or current direction as the magnetic flux, so that the magnetic sensitivity is deteriorated.

In this embodiment, the insulation is provided by the thick selective oxide film. However, the insulation may be provided by using a trench etched in a trench shape. In this embodiment, since a pn junction is formed by a silicon semiconductor layer, an oxide film can be easily formed. However, in a compound semiconductor such as GaAs, a semi-insulating region having a large electric resistance is formed by irradiation with protons or the like. You can also.

In this embodiment, the electrodes 21 and 2 of the p-type layer 13 are used.
A groove is dug into the p-type layer 13 as 2 and 47, and p
The mold polysilicon 53 is embedded to realize the reliability of the electrical connection. This is for the following reason. That is, in order to increase the Hall voltage and decrease the electrical resistance, it is necessary to decrease the impurity concentration and shorten the electrical length. However, if an electrode is simply taken from above for a semiconductor with a low impurity concentration, the equipotential lines near the electrode will be distorted.
The current flowing through the semiconductor is not parallel to the substrate near the electrode. For this reason, when the element is extremely miniaturized, the magnetic field sensitivity deteriorates. In order to solve this problem, in this embodiment, an electrode is embedded in a p-type layer so that a current flows in parallel with the junction.

The embodiments described above can be easily realized by conventional techniques such as photolithography, etching, diffusion, selective oxidation, and CVD.

FIG. 15 shows that a thin-film single-crystal silicon is grown on an insulator, that is, directly when the substrate is an insulator, and when the substrate is a semiconductor substrate, through an insulating film to form a p-type layer and an n-type silicon. This is an embodiment in which the layers are arranged side by side to provide a bond. This embodiment has a structure in which a thin-film semiconductor layer is provided on an insulating film formed on a semiconductor substrate, and a pn junction 14 is provided perpendicular to the substrate.

With such a structure, the thickness of the semiconductor in the direction in which the magnetic flux passes can be made extremely thin, and the width of the semiconductor layer in the direction in which the Hall voltage is generated can be increased, so that the Hall voltage is large.

The method of manufacturing this semiconductor magnetoresistive element is based on a low-concentration p-type silicon substrate whose surface is thermally oxidized to form an oxide film 62.
A window is opened in 61, and a p-type silicon film 63 is
Is deposited. After that, the p-type silicon film 63 is monocrystallized by performing a laser sweep from the window where the deposited p-type silicon film 63 is in contact with the single-crystal silicon substrate 61. This technology uses silicon-on-insulator (Silicon).
con on Insulator (hereinafter referred to as SOI) technology.

After that, the silicon single crystal film 63 is etched by dry etching to form a p-type region 63 and an n-type region 64.
Is electrically separated from the substrate.

Next, a thin oxide film is provided on the surface of the single crystal silicon film by low-temperature dry thermal oxidation. Further, a nitride film is deposited on the surface by the CVD method, and the nitride film and the thin oxide film on the n-type silicon region 64 are removed by dry etching. After the arsenic ion implantation using the nitride film as a mask, annealing is performed to provide an n-type region 64 to form the pn junction 14. At this time, the n-type region is sufficiently drive-diffused by annealing so that the junction enters under the mask at the time of ion implantation.

Next, an oxide film 65 is deposited by a CVD method, and a contact hole is formed by dry etching. Further, the electrode 66 is formed by sputtering.

FIGS. 16 and 17 show an embodiment in which a magnetic head for reading magnetic data is used. That is, FIG. 16 is a perspective view of the entire magnetic head, and FIG. 17 is an enlarged cross-sectional view taken along the line CC of FIG. The magnetoresistive elements used in these figures are the same as those of the differential type shown in FIGS. FIG. 17 is a cross section of the p-type layer 13 taken in a direction perpendicular to the current from above the central electrode 47 in FIG. The current flows in the p-type layer 13 in a direction to pass through the paper from the near side to the far side. The n-type layer 12 flows in the opposite direction.

The manufacturing process of this embodiment is as follows.
First, a signal processing unit 77 such as a magnetoresistive element and an amplifier is provided by a general semiconductor integrated circuit manufacturing technique. In the direction in which the magnetic flux of the magnetoresistive element portion of the substrate passes, the groove
71 will be provided. The groove 71 is intended to efficiently pass the magnetic flux through the magnetoresistive element.

Next, an oxide film 18 is provided by a CVD method for insulation. Further, the lower yoke 72 is provided by sputtering a magnetic material. The yoke 72 is prepared for guiding magnetic flux from a magnetic medium such as a magnetic disk to the sensor section 76 together with an upper yoke 75 described later. The yoke may be a soft magnetic material having a high magnetic permeability, and for example, a permalloy or a CoZrMoNi-based alloy may be used. The thickness of the yoke depends on the magnetic permeability of the magnetic material, the magnetic path length, or the recording density of the magnetic medium, but is, for example, about 2 μm.

Next, a spacer 73 serving as a magnetic gap is provided by depositing and etching a thin oxide film by the CVD method. The material of the spacer 73 is preferably a nonmagnetic material such as SiO ₂ . If this thickness is used as the head of a magnetic recording device for a computer, for example, 0.3
About 0.5 μm.

Next, a thick spacer 74 is provided to reduce the leakage magnetic flux between the upper yoke 75 and the lower yoke 72 and improve the magnetic flux efficiency.

The spacer 74 is preferably made of a photosensitive polyimide resist or the like. This thickness is about 2-3
μm is recommended. An upper yoke 75 is formed thereon by sputtering. Finally, chips are cut out from the wafer and polished to the tip of the magnetic head to finish.

In this magnetic head, since the signal processing unit 77 such as an amplifier integrated near the magnetic sensing unit is provided, a magnetic head which is extremely resistant to noise and has high sensitivity can be obtained. The effect of the magnetic field on the signal processing unit 77 depends on the layout, but there is almost no problem if the relative permeability of the yoke is about 500 to 1000 or more. If a groove is dug around the signal processing unit 77 and surrounded by a magnetic film, the magnetic shield is practically sufficient.

[0085]

According to the semiconductor magnetoresistive element of the present invention, unlike the conventional magnetoresistive element, the Hall voltage acts in the direction of increasing the magnetic field sensitivity, and crosses the junction surface by an exponential function of the generated Hall voltage. Since the current changes greatly, the magnetoresistance effect is very large. As a result, when trying to obtain the same effect with a conventional Hall element or magnetoresistive element,
While one side requires a large area of several tens to several hundreds of μm, according to the present invention, one side has a size of several μm and a high-performance one can be obtained.

Further, the region where the carriers are recombined is in the bulk and can be very stable without change over time. Furthermore, miniaturization and integration are easy, and a magnetic sensor array having a very high magnetic spatial resolution integrated with a control circuit can be constructed. Further, by providing a yoke for guiding magnetic flux, it can be applied as a magnetic head for reading magnetic data.

As can be seen from the above description, according to the present invention, a sufficiently large magnetoresistive effect can be obtained even when silicon is used, and the magnetic sensitive portion and the amplifier can be provided on the same substrate. For this reason, the signal is amplified immediately after the sensor, and the signal can be transmitted through the lead wire to the main body of the magnetic recording apparatus with a large amplitude and low impedance, so that a reading magnetic head having a high S / N can be provided.

[Brief description of the drawings]

FIG. 1 is an explanatory plan view of a magnetoresistive element according to an embodiment of the present invention.

FIG. 2 is an explanatory view of an AA cross section in FIG. 1;

FIG. 3 is an explanatory sectional view of a pin junction magnetoresistive element of the present invention.

FIG. 4 is an explanatory diagram by a band diagram of a p-type layer and an n-type layer when no magnetic field is applied.

FIG. 5 is an explanatory diagram based on a band diagram of a p-type layer and an n-type layer when a magnetic field is applied.

FIG. 6 is an explanatory diagram based on a band diagram viewed from a conductive band side when a magnetic field is applied.

FIG. 7 is an explanatory diagram based on a band diagram viewed from a valence band side when a magnetic field is applied.

FIG. 8 is an explanatory diagram based on a band diagram in the case of a pin junction.

FIG. 9 is a diagram illustrating a change in a forward bias voltage when a Hall voltage is generated and illustrating the principle of the present invention.

FIG. 10 is an explanatory view in a plan view when a differential according to another embodiment of the present invention is used.

FIG. 11 is an explanatory view taken along the line BB of FIG. 10;

FIG. 12 is an explanatory diagram of a plan view of a differential according to still another embodiment of the present invention.

FIG. 13 is an explanatory diagram showing a cross section of FIG. 12;

FIG. 14 is an explanatory sectional view showing still another embodiment of the present invention.

FIG. 15 is an explanatory view of a perspective view showing still another embodiment of the present invention.

FIG. 16 is a perspective view of an embodiment when a magnetic head is used.

FIG. 17 is an explanatory diagram along a CC section of FIG. 16;

[Explanation of symbols]

11 Semiconductor substrate 12 First conductivity type layer (n-type layer) 13 Second conductivity type layer (p-type layer) 14 pn junction 19, 20, 21, 22 electrode 25 Forward bias constant voltage source 28 i-layer 32 electrons ( majority carrier) 33 hole (majority carrier) 51 thick oxide film (made of electrical resistance large region) 72 lower magnetic yoke 75 upper magnetic yoke 77 signal processing unit R _{L, R R} resistance D _{L, D R} diode

Claims (7)

(57) [Claims] A first conductive type layer of a semiconductor on a substrate;
Pn junction or an intrinsic semiconductor layer in between
An intervening pin junction is formed, and the two conductive layers are
At least one is parallel to the surface of the pn junction or pin junction
Many carriers flow in various directions and the pn junction
Or, if a forward bias voltage is not applied to the pin junction
That a magnetoresistive element, wherein the plurality is provided with means for detecting a change in current due to carrier flow, the pn junction or pin junction face and the component perpendicular to the magnetic field by the applied magnetic field in a direction parallel to A semiconductor magnetoresistive element for detecting a change in the magnetic field based on a change in current of the majority carrier moving in a deviated direction. 2. The electrode for bias voltage application is provided at a center of the first conductivity type layer and a center of the second conductivity type layer, respectively, in a direction parallel to the pn junction or the pin junction. An electrode for flowing a current is formed at at least one end of the first conductivity type layer and the second conductivity type layer, and an electrode provided at an end of the first conductivity type layer and the semiconductor magnetoresistive element of the two conductive electrode provided on an end portion of the conductive type layer is connected by a resistor or a diode externally formed by the current detecting means of the majority carrier according to claim 1, wherein. 3. An electrode is formed so that the majority carrier flows from the center of the first conductivity type layer and the second conductivity type layer to the left and right ends, or from the left and right both ends to the center. a differential voltage based on the current or said current flow through the left and right to detect a change in the magnetic field according to claim 1 or
3. The semiconductor magnetoresistive element according to 2. 4. The first or second conductive type layer is formed in a vertical direction of the substrate, and the first or second conductive type layer is formed on an upper surface side of the two conductive type layers. the lateral large a region of the electrical resistance around the conductive type layer is formed, any one of claims 1-3 comprising reducing the vertical joint surfaces of the first and second conductivity type layer Semiconductor magnetoresistive element. 5. The first conductivity type layer and the second conductivity type layer are formed on the substrate either directly or in a lateral direction via an insulating film, and the pn junction or the pin junction is perpendicular to the substrate. semiconductor magnetoresistive element according to any one of the formed comprising claim 1-4. 6. The majority carrier flows in both the first conductivity type layer and the second conductivity type layer in parallel with the pn junction or the pin junction, and current directions thereof are opposite to each other. semiconductor magnetoresistive element according to any one of claims 1 to 5, characterized in. 7. A semiconductor magnetoresistance device of any one of claims 1 to 6 in which recombination centers is provided in a portion of the pn junction or pin junction.