JP5073429B2 - Magnetic sensor, Hall element, magnetoresistive effect element, method for producing Hall element, method for producing magnetoresistive effect element - Google Patents

Description

  The present invention relates to a magnetic sensor having an operation layer made of a group III nitride semiconductor.

  It is known that a magnetic sensor such as a Hall element or a magnetoresistive effect element having an operating layer made of a semiconductor material exhibits higher sensitivity as the carrier mobility of the semiconductor material used increases. Therefore, conventionally, a compound semiconductor exhibiting a high electron mobility such as InSb or InAs has been used for the operation layer of the magnetic sensor (for example, see Non-Patent Document 1). For example, as a magnetic sensor for a DC brushless motor, a large number of Hall elements using the Hall effect of a thin film such as InSb or InAs are used.

A magnetic sensor in which an operation layer is formed of a group III nitride semiconductor that is a wide band gap semiconductor is also known (see, for example, Patent Document 1 and Patent Document 2). Such a magnetic sensor has an advantage that a characteristic change hardly occurs even at a high temperature, although the sensitivity is inferior to a magnetic sensor using InSb or InAs. In particular, Patent Document 2 states that a magnetic sensor having an Al _x G _1-x N / GaN (0.3 <x ≦ 0.5) heterostructure in an operation layer can operate well at 300 ° C. or higher. Is disclosed.

"Physical properties of InSb single crystal thin film and application of magnetic sensor" IEEJ Transaction, Vol.123, No.3 (2003), pp.69-78 JP 2003-060255 A JP 2006-080338 A

  As pointed out in Patent Document 1, in the case of a magnetic sensor manufactured using InSb or InAs, the Hall voltage measured under the condition of a constant magnetic flux density is temperature-dependent. It is widely known that there is a drawback that it cannot be used.

  Further, in the case of a magnetic sensor in which an operation layer is formed so as to have an AlGaN / GaN heterojunction as disclosed in Patent Document 1 and Patent Document 2, the temperature characteristics are superior to those using InSb or InAs. However, due to the large piezoelectric polarization effect and spontaneous polarization effect, the two-dimensional electron gas concentration in the vicinity of the interface between the GaN layer and the AlGaN layer becomes excessively large, and it is difficult to obtain sufficient sensitivity. It was.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a magnetic sensor that has good temperature characteristics and operates with high sensitivity.

In order to solve the above-mentioned problems, the invention of claim 1 is a magnetic sensor comprising an operation layer having a heterojunction structure of a GaN layer and an AlGaN layer on a predetermined substrate, wherein the substrate has an m-plane surface. or GaN is a plane, AlN, AlGaN, ZnO, single crystal substrate of hexagonal material selected from alpha-SiC, Oh Rui surface is either a sapphire single crystal substrate is a r-plane, said operating layer The crystal structure is a wurtzite structure and the c-axis is substantially parallel to the surface of the substrate.
The invention according to claim 2 is the magnetic sensor according to claim 1, wherein the two-dimensional electron gas concentration of the two-dimensional electron gas region formed in the operation layer is 2 × 10 ¹² / cm ³ or less. It is characterized by.

According to a third aspect of the present invention, the Hall element is the magnetic sensor according to the first or second aspect, and includes an input electrode at each of the first ends of the operation layer facing each other in plan view, Each of the second ends facing each other in a direction substantially orthogonal to the direction connecting the first ends is provided with an output electrode.

According to a fourth aspect of the present invention, there is provided the Hall element according to the third aspect, wherein the operation layer has a cross-shaped portion having a substantially cross shape in a plan view, and the two cross-shaped portions facing each other. Each of the first tip portions includes the input electrode, and each of the two second tip portions different from the first tip portion includes the output electrode.

According to a fifth aspect of the present invention, the magnetoresistive effect element is the magnetic sensor according to the first or second aspect , wherein the magnetoresistive effect element includes a terminal electrode at each of opposing ends of the surface of the operating layer, and the terminal electrode A plurality of short-circuit electrodes are provided between them.

The invention of claim 6 is a method for manufacturing a Hall element, wherein a GaN layer forming step for epitaxially forming a GaN layer on a predetermined substrate, and an AlGaN layer forming for epitaxially forming an AlGaN layer on the GaN layer are formed. An operation layer forming step of forming an operation layer for forming a heterojunction structure between the GaN layer and the AlGaN layer, and a first end portion of the operation layer facing each other in plan view. Forming an input electrode, and forming an output electrode on each of the second ends facing each other in a direction substantially orthogonal to the direction connecting the first ends, , the surface is an m-plane or a-plane GaN, AlN, AlGaN, ZnO, single crystal substrate of hexagonal material selected from alpha-SiC, Oh Rui surface r surface Using one of the sapphire single crystal substrates, in the operation layer forming step, the operation layer having a crystal structure of a wurtzite structure is formed so that the c-axis is substantially parallel to the surface of the substrate. It is characterized by that.
The invention of claim 7 is the Hall element manufacturing method according to claim 6, wherein in the operation layer forming step, the two-dimensional electron gas concentration in the two-dimensional electron gas region is 2 × 10 ¹² / cm ³ or less. The operation layer is formed so that

The invention according to claim 8 is the Hall element manufacturing method according to claim 6 or claim 7, wherein the operation layer forming step removes a part of the operation layer and thereby the operation layer is viewed in plan view. And a removing step of forming a cross-shaped portion having a substantially cross-shape, wherein the input electrode is formed on each of the two first tip portions of the cross-shaped portion facing each other. In addition, the output electrode is formed on each of two second tip portions different from the first tip portion.

The invention of claim 9 is a method of manufacturing a magnetoresistive effect element, wherein a GaN layer forming step for epitaxially forming a GaN layer on a predetermined substrate, and an AlGaN layer for epitaxially forming an AlGaN layer on the GaN layer A layer forming step, an operation layer forming step of forming an operation layer for forming a heterojunction structure of the GaN layer and the AlGaN layer, and a terminal electrode on each of opposite ends of the surface of the operation layer. Forming a plurality of short-circuit electrodes between the terminal electrodes, and the substrate is selected from GaN, AlN, AlGaN, ZnO, α-SiC whose surface is an m-plane or a-plane hexagonal single crystal substrate of crystal material, Oh Rui using either surface of the sapphire single crystal substrate is a r-plane, in the operation layer forming step, the crystal structure to be There generally is formed so as to be parallel to the active layer of c-axis surface of said substrate is a wurtzite structure, characterized in that.
A tenth aspect of the present invention is the method of manufacturing a magnetoresistive effect element according to the ninth aspect, wherein the two-dimensional electron gas concentration in the two-dimensional electron gas region is 2 × 10 ¹² / cm in the operation layer forming step. ^The operation layer is formed to be ³ or less.

According to the first and second aspects of the present invention, the concentration of the two-dimensional electron gas stored in the vicinity of the junction interface is reduced by suppressing the piezoelectric polarization effect and the spontaneous polarization effect in the heterojunction between the GaN layer and the AlGaN layer. By being suitably suppressed, a magnetic sensor that operates with approximately the same high measurement sensitivity from room temperature to high temperature is realized.

According to the invention of claim 3 , claim 4 , and claim 6 to claim 8 , the piezoelectric polarization effect and the spontaneous polarization effect in the heterojunction between the GaN layer and the AlGaN layer are suppressed, so By suitably suppressing the concentration of the stored two-dimensional electron gas, it is possible to realize a Hall element that has high measurement sensitivity at room temperature and can be used with high measurement sensitivity at room temperature.

According to the invention of claim 5, claim 9, and claim 10 , two-dimensionally stored in the vicinity of the junction interface by suppressing the piezoelectric polarization effect and the spontaneous polarization effect in the heterojunction of the GaN layer and the AlGaN layer. By suitably suppressing the concentration of the electron gas, a magnetoresistive element that operates with substantially the same measurement sensitivity from room temperature to high temperature is realized.

<First Embodiment>
In the present embodiment, a Hall element that is a magnetic sensor capable of detecting a magnetic field using the Hall effect of a semiconductor will be described.

<Outline of Hall element>
FIG. 1 is a top view of the Hall element 10 according to the first embodiment of the present invention. FIG. 2 is a cross-sectional view of the Hall element 10 (through a substantially central portion) in the cross section AB of FIG.

  The Hall element 10 includes an operation layer 2, two input electrodes 3a and 3b, and two output electrodes 4a and 4b on a substrate 1. The operation layer 2 is formed to have a cross shape (cross shape) at the center when the Hall element 10 is viewed in plan (top view). The cruciform is preferably formed so that each line has a width of about several tens of μm and a length of several hundreds of μm. For example, the width is 50 μm and the length is 200 μm.

  The two input electrodes 3a and 3b are provided so as to cover the two tip portions of the operation layer 2 facing each other in the cross shape, and the two output electrodes 4a and 4b are operated. Each of two cruciform tip portions of the layer 2 different from the input electrode is provided so as to cover the tip portion.

  With the Hall element 10 placed in a vertical magnetic field from the front surface to the back surface, a constant current is passed between the two input electrodes 3a and 3b (in the case of constant current driving), or a constant voltage is applied ( In the case of constant voltage driving) and the Hall effect in the operation layer 2, a potential difference (Hall voltage) is generated between the two output electrodes 4a and 4b. By measuring the Hall voltage, the magnetic flux density of the magnetic field can be obtained as a value proportional to this (under a constant temperature condition).

  FIG. 3 is a schematic cross-sectional view of the laminated structure 5 used for forming the Hall element 10. The laminated structure 5 is obtained by epitaxially forming the operation layer 2 on the substrate 1. The operation layer 2 has a structure in which a first layer 2a and a second layer 2b are stacked. There are several tens of buffer layers (not shown) made of AlN or GaN between the substrate 1 and the first layer 2a for the purpose of improving the crystal quality of the first layer 2a and the second layer 2b. It is preferable to have a thickness of about nm.

  Schematically speaking, the Hall element 10 according to the present embodiment is obtained in a plan view as shown in FIG. 1 after obtaining the laminated structure 5 by epitaxially forming the operation layer 2 on the substrate 1. In some cases, the operation layer 2 is removed using a photolithographic process and RIE (reactive ion etching) so that a cross shape remains in the center, and then the input electrodes 3a and 3b and the two output electrodes 4a, 4b is provided by using a photolithography process and an EB (electron beam) vapor deposition technique. A preferable example is that the etching depth for forming the cross shape is, for example, about the same as or slightly larger than the thickness of the operation layer 2 (to the extent that the surface of the substrate 1 is slightly etched). is there.

As the substrate 1, a monocrystalline substrate of hexagonal material selected from GaN, AlN, AlGaN, ZnO, α-SiC whose surface is m-plane or a-plane, γ-LiAlO ₂ single-crystal substrate whose surface is a-plane, Alternatively, any of sapphire single crystal substrates whose surface is an r-plane is used. The reason for using these substrates will be described later.

  The first layer 2a of the operation layer 2 is a semiconductor layer made of GaN which is one of group III nitrides. The second layer 2b is a semiconductor layer made of AlGaN, which is also one of group III nitrides. The first layer 2a is preferably formed to a thickness of about several μm. The second layer 2b is preferably formed to a thickness of about several tens of nm. Details of the operation layer 2 will be described later.

  Each of the input electrodes 3a and 3b and the output electrodes 4a and 4b is an example that is preferably provided as a multilayer electrode made of Ti / Al / Ni / Au.

<Relationship between operation layer configuration and Hall element characteristics>
As described above, in the operation layer 2, the first layer 2 a and the second layer 2 b made of group III nitrides having different compositions and band gaps are stacked. A joining interface is formed. At such a heterojunction interface, a conduction band valley is generated due to the difference in band gap and electron affinity between the two layers, and as a result, electrons are stored within a range of several nanometers from the stacked interface of both layers in the first layer 2a. A two-dimensional electron gas region 2g is formed. That is, the operation of the Hall element 10 is realized by using the two-dimensional electron gas stored in the two-dimensional electron gas region 2g as a carrier.

  However, it is generally known that when a Hall element whose operation layer is made of a semiconductor is driven at a constant current, the measurement sensitivity becomes higher (a higher Hall voltage is obtained) as the carrier concentration in the operation layer is lower. Therefore, also in the Hall element 10 according to the present embodiment, the concentration of the two-dimensional electron gas in the two-dimensional electron gas region 2g is suppressed to such an extent that good measurement sensitivity can be obtained (the concentration of the two-dimensional electron gas is The operation layer 2 is configured so as not to become too large.

Specifically, the first layer 2a and the second layer 2b constituting the operation layer 2 both have a wurtzite crystal structure, and the c-axis is substantially parallel to the surface of the substrate 1. It is formed as follows. More specifically, the substrate 1 is a single crystal substrate of a hexagonal material selected from GaN, AlN, AlGaN, ZnO, α-SiC whose surface is m-plane or a-plane as described above, and the surface is a-plane. By using either a γ-LiAlO ₂ single crystal substrate or a sapphire single crystal substrate whose surface is an r-plane, the operation layer 2 is also formed so that its plane orientation is the m-plane or the a-plane.

By having such a configuration, in the Hall element 10 according to the present embodiment, the two-dimensional electron gas concentration in the two-dimensional electron gas region 2g is suppressed to 2 × 10 ¹² / cm ³ or less. As a result, the Hall element 10 has good measurement sensitivity.

For example, a GaN layer having an electron concentration of 1 × 10 ¹² / cm ³ is formed as a first layer 2a with a thickness of 2 μm on each of the various substrates 1 as described above, and Al _0.2 Ga is formed as the second layer 2b. _In the case of the Hall element 10 in which the _0.8 N layer is formed to a thickness of 25 nm and the etching depth for dividing the cross-shaped portion of the operation layer 2 is 2 μm, the input current is 2 mA in a magnetic field with a magnetic flux density of 500 G. When the constant current drive is performed while maintaining the voltage, the Hall voltage is 62 to 63 mV. Further, when the Hall element is similarly heated in a magnetic field having a magnetic flux density of 500 G from room temperature to 600 ° C. and constant current driving is performed with the input current maintained at 2 mA, the temperature change rate from room temperature to 600 ° C. is A result of 0.005% / ° C. or less is obtained.

  As a result, the Hall element 10 having the operation layer 2 formed by laminating the first layer 2a made of GaN and the second layer 2b made of AlGaN has a stable constant current in a temperature range from room temperature to 600 ° C. This is nothing but an indication of realizing the drive operation. In other words, the Hall element 10 according to the present embodiment can be used with good measurement sensitivity almost equal to room temperature by constant current driving not only at room temperature but also at high temperature.

<Method for forming laminated structure>
Next, a method for forming the laminated structure 5 for realizing the operation layer 2 having the above-described configuration will be described. The laminated structure 5 can be formed by the MOCVD method. That is, after placing the substrate 1 on a susceptor in a predetermined reaction tube and raising the temperature of the substrate 1 to a predetermined reaction temperature (formation temperature), the group III source gas (first layer) is maintained while maintaining the reaction temperature. In the case of 2a, Ga source gas, and in the case of the second layer 2b, Ga source gas and Al source gas) and NH ₃ gas, which is a group V source gas, are made to flow together with a carrier gas at a predetermined flow rate, respectively. The first layer 2a and the second layer 2b having a structure can be formed epitaxially sequentially. The formation temperature of the first layer 2a is preferably a predetermined temperature in the range of 950 ° C. to 1200 ° C., for example, 1000 ° C., and the formation temperature of the second layer 2b is a predetermined temperature in the range of 950 ° C. to 1200 ° C., For example, the temperature is preferably 1000 ° C. Note that, as described above, a buffer layer made of GaN or AlN is previously formed on the substrate 1 at a predetermined temperature in the range of 400 ° C. to 600 ° C., for example, 500 ° C. More preferably, the first layer 2a and the second layer 2b are formed.

  The stacked structure 5 is formed as long as the electron concentration in the first layer 2a and the composition ratio of the second layer 2b can be controlled. Epitaxial growth methods other than the MOCVD method, such as MBE, HVPE, It may be an embodiment performed by a method appropriately selected from a vapor phase growth method such as LPE or a liquid phase growth method, or may be an embodiment performed by combining different growth methods.

As described above, according to the present embodiment, the substrate 1 is made of a single hexagonal material selected from GaN, AlN, AlGaN, ZnO, and α-SiC whose surface is the m-plane or a-plane as described above. Either a crystal substrate, a γ-LiAlO ₂ single crystal substrate whose surface is a-plane, or a sapphire single crystal substrate whose surface is an r-plane is used, and a first layer 2a made of GaN and a first layer made of AlGaN are formed thereon. By forming an operation layer composed of two layers 2b so as to have a wurtzite crystal structure and so that the c-axis is oriented substantially parallel to the surface of the substrate, it has high measurement sensitivity at room temperature. Thus, a Hall element that can be used with a measurement sensitivity equivalent to room temperature even at high temperatures is realized.

<Second Embodiment>
In the present embodiment, a magnetoresistive effect element that is a magnetic sensor capable of detecting a magnetic field using the magnetoresistive effect of a semiconductor will be described.

  FIG. 4 is a schematic cross-sectional view showing a configuration of the magnetoresistive effect element 200 according to the present exemplary embodiment. The magnetoresistive effect element 200 includes a substrate 201, an operation layer 202 formed on the substrate 201, which includes a first layer 202a and a second layer 202b, and two layers formed on the surface of the operation layer 202. Terminal electrodes 203a and 203b and a plurality of short-circuit electrodes 204 formed between the two terminal electrodes 203a and 203b are provided.

  The magnetic flux density of the magnetic field can be obtained by measuring the resistance change generated between the two terminal electrodes 203a and 203b in a state where the magnetoresistive effect element 200 is placed in a vertical magnetic field from the front surface to the back surface. it can.

  The substrate 201 is the same as the substrate 1 of the Hall element 10 according to the first embodiment. The operation layer 202 is formed in the same manner as the operation layer 2 of the Hall element 10 according to the first embodiment. That is, both the first layer 202a and the second layer 202b constituting the operation layer 202 are formed so as to have a wurtzite crystal structure and the c-axis is substantially parallel to the surface of the substrate 1. To do.

  The terminal electrodes 203a and 203b and the short-circuit electrode 204 are preferably provided as multilayer electrodes made of Ti / Al / Ni / Au. These can be formed by using a photolithographic process and an EB deposition method.

Forming the operation layer 202 as described above is the same as forming the stacked structure 5 used for forming the Hall element 10 in the first embodiment. Accordingly, also in the magnetoresistive effect element 200 according to the present exemplary embodiment, in the operation layer 202, the heterojunction between the first layer 202a and the second layer 202b is similar to the Hall element 10 according to the first exemplary embodiment. A junction interface is formed, and in the vicinity of the hetero junction interface of the second layer 202b, a two-dimensional electron gas region 202g serving as a carrier movement region has a two-dimensional electron gas concentration of 2 × 10 ¹² / cm ³ or less. It is formed so that it is.

  Since the requirements for the operation layer 202 of the magnetoresistive effect element 200 are the same as the requirements for the operation layer 2 of the Hall element 10 according to the first embodiment, the operation layer 202 has the Hall element as described above. By having the same characteristics as the ten operation layers 2, high measurement sensitivity is realized in the magnetoresistive effect element 200.

  That is, the magnetoresistive effect element according to the present embodiment can be used with good measurement sensitivity even at a high temperature, like the Hall element according to the first embodiment.

(Example 1 and Comparative Example 1)
As Example 1, the Hall element 10 according to the first embodiment was created. Specifically, seven types of Hall elements 10 having different types of the substrate 1 and the same operation layer 2 were prepared.

  The substrate 1 is a single crystal substrate having a diameter of 2 inches each, m-plane ((10-10) plane) GaN substrate, m-plane 6H-SiC substrate, m-plane ZnO substrate, a-plane ((11-20) plane). Eight substrates of a GaN substrate, an m-plane 6H—SiC substrate, an m-plane ZnO substrate, an r-plane ((10-12) plane) sapphire substrate, and an a-plane ((100) plane) were prepared. In addition, a c-plane ((0001 plane)) sapphire substrate was prepared as the substrate 1 in order to produce a Hall element serving as Comparative Example 1.

For each substrate 1, a laminated structure 5 was produced by a predetermined MOCVD apparatus. In the MOCVD apparatus, a group III source gas supply system and a group V source gas supply system are provided separately, so that both the group III source gas and the group V source gas can be individually supplied to the vicinity of the susceptor together with the carrier gas. It has become. TMG and TMA were used as the group III source gas, and NH ₃ was used as the group V source gas. As the carrier gas, one or both of hydrogen gas and nitrogen gas was appropriately used.

  Specifically, first, each single crystal substrate is placed on a susceptor in an MOCVD apparatus, a substrate temperature is set to 1100 ° C., heat treatment (thermal cleaning) is performed for 20 minutes, and then the temperature is set to 500 ° C. A buffer layer made of AlN was formed to a thickness of 30 nm.

After the buffer layer was formed, the substrate temperature was set to 1050 ° C., the GaN film as the first layer 2a was formed to a thickness of 2 μm, and the Al _0.2 Ga _0.8 N film as the second layer 2b was subsequently formed to a thickness of 25 nm. With respect to the operation layer 2 formed in this way, it was confirmed by X-ray diffraction measurement that the c-axis was substantially parallel to the substrate 1.

When the two-dimensional electron concentration in the two-dimensional electron gas region 2g was measured for the obtained laminated structure 5, it was confirmed that it was about 1 × 10 ¹² / cm ² in any sample according to this example. . On the other hand, about the sample which concerns on a comparative example, it became a value about 1 * 10 < ¹³ > / cm < ² > one order larger than this.

  Next, the surface of the laminated structure 5 is formed to a depth of 2 μm by a photolithography process and an RIE method so that a cross shape is formed in which two lines having a width of 50 μm and a length of 200 μm are orthogonal to each other at the center. It was etched.

  Subsequently, a metal pattern made of Ti / Al / Ni / Au (thicknesses in order 25/75/15/100 nm) is formed in a size of 100 μm square at each tip portion of the cross shape by photolithography process and EB deposition. Then, the input electrodes 3a and 3b and the output electrodes 4a and 4b were formed by performing an alloying process at a temperature of 850 ° C. for 30 seconds in an infrared rapid heating furnace. Thus, the Hall elements according to Example 1 and Comparative Example 1 were obtained.

  In order to make it possible to evaluate the characteristics of these Hall elements, a CVD nitride film and a photolithography process were used to form a silicon nitride passivation film on the surface, and then contact holes were opened in each electrode portion, and wire bonding was performed. .

  In this state, the electrical characteristics of each Hall element were evaluated. Specifically, the Hall voltage was measured in a magnetic field having a magnetic flux density of 500 Gauss with a constant drive current of 2 mA applied. Further, the rate of change of the Hall voltage with respect to the temperature (temperature change rate) in the constant current driving operation was evaluated while heating from room temperature to 600 ° C.

  FIG. 5 is a diagram showing a list of evaluation results for such Hall elements. As can be seen from FIG. 5, in any of the Hall elements according to Example 1, the Hall voltage at room temperature is about 62 to 63 mV, whereas the Hall voltage at room temperature of the Hall element according to Comparative Example 1 is It was only about 6.2 mV. That is, it was confirmed that the Hall element according to the first embodiment is a Hall element having a good measurement sensitivity at room temperature. Thus, the result that the Hall element according to Example 1 having a small two-dimensional electron concentration in the two-dimensional electron gas region has a larger Hall voltage than the Hall element according to Comparative Example 1 is that the c-axis is a substrate. It shows that the formation of the operation layer so as to be substantially parallel to the surface is effective in realizing a Hall element having excellent measurement sensitivity.

  Moreover, the temperature change rate of the Hall voltage was 0.005% / ° C. or less for both the Hall elements of Example 1 and Comparative Example 1. That is, it was confirmed that the Hall element according to the first embodiment has a measurement sensitivity substantially the same as that at room temperature even at a high temperature.

(Example 2)
The Hall element according to the first embodiment is similar to the first embodiment except that an m-plane GaN substrate is used as the substrate 1 and the composition of the AlGaN layer as the second layer 2b is variously changed. 10 was produced. Specifically, five types of Hall elements 10 in which x values of Al _x G _1-x N were 0.16, 0.20, 0.27, 0.34, and 0.42 were manufactured.

  For the obtained Hall element 10, the Hall voltage at room temperature by constant current driving and the temperature change rate of the Hall voltage up to a range of 600 ° C. were measured as in Example 1.

  FIG. 6 is a table showing the evaluation results of the Hall element together with the composition of the second layer 2b. As can be seen from FIG. 6, in any of the Hall elements according to Example 2, the Hall voltage at room temperature was about 62 to 63 mV, which was larger than that of the Hall element according to Comparative Example 1.

  In addition, the temperature change rate of the Hall voltage was 0.005% / ° C. or less for all the Hall elements of Example 2.

  That is, according to this example, it was confirmed that the Hall element according to the first embodiment has good measurement sensitivity regardless of the composition of the AlGaN layer.

It is a top view of Hall element 10 concerning a 1st embodiment. It is sectional drawing of the Hall element 10 in the AB cross section of FIG. 3 is a schematic cross-sectional view of a laminated structure 5 used for forming the Hall element 10. FIG. It is a cross-sectional schematic diagram which shows the structure of the magnetoresistive effect element 200 which concerns on 2nd Embodiment. It is a figure which lists and shows the evaluation result about the Hall element which concerns on Example 1 and Comparative Example 1. FIG. It is a figure which lists and shows the evaluation result about the Hall element which concerns on Example 2 with a composition of 2nd layer 2b.

Explanation of symbols

1, 201 substrate 10 Hall element 2, 202 operation layer 2a, 202a (operation layer) first layer 2b, 202b (operation layer) second layer 2g, 202g two-dimensional electron gas region 3a, 3b input electrode 4a, 4b Output electrode 5 Laminated structure 200 Magnetoresistive effect element 203a, 203b Terminal electrode 204 Short-circuit electrode

Claims (10)

A magnetic sensor comprising an operating layer having a heterojunction structure of a GaN layer and an AlGaN layer on a predetermined substrate,
The substrate is either a single crystal substrate of hexagonal material selected from GaN, AlN, AlGaN, ZnO, α-SiC whose surface is m-plane or a-plane, or sapphire single-crystal substrate whose surface is r-plane Yes,
The operation layer has a crystal structure of a wurtzite structure and a c-axis substantially parallel to the surface of the substrate.
Magnetic sensor characterized by the above. The magnetic sensor according to claim 1,
The two-dimensional electron gas concentration of the two-dimensional electron gas region formed in the working layer is 2 × 10 ¹² / cm ³ or less;
Magnetic sensor characterized by the above. 3. The magnetic sensor according to claim 1, wherein an input electrode is provided at each of the first end portions of the operation layer facing each other in a plan view, and the direction in which the first end portions are connected to each other. Each of the second ends facing each other in a substantially orthogonal direction is provided with an output electrode.
Hall element characterized by the above. The hall element according to claim 3,
The operation layer has a cross-shaped portion having a substantially cross shape in plan view, and includes the input electrode at each of two first tip portions facing each other of the cross-shaped portion, and the first layer Each of the two second tip portions different from the tip portion includes the output electrode.
Hall element characterized by the above. 3. The magnetic sensor according to claim 1, wherein a terminal electrode is provided at each of opposite ends of the surface of the operation layer, and a plurality of short-circuit electrodes are provided between the terminal electrodes. ,
A magnetoresistive effect element. A method for producing a Hall element, comprising:
A GaN layer forming step of epitaxially forming a GaN layer on a predetermined substrate;
An AlGaN layer forming step of epitaxially forming an AlGaN layer on the GaN layer;
An operation layer forming step of forming an operation layer for forming a heterojunction structure between the GaN layer and the AlGaN layer,
An input electrode is formed at each of the first end portions of the operation layer facing each other in plan view, and second end portions of the operation layer facing each other in a direction substantially perpendicular to a direction connecting the first end portions. An electrode forming step for forming an output electrode for each;
With
As the substrate, either a single crystal substrate of hexagonal material selected from GaN, AlN, AlGaN, ZnO, α-SiC whose surface is m-plane or a-plane, or sapphire single-crystal substrate whose surface is r-plane Use
In the operation layer forming step, the operation layer whose crystal structure is a wurtzite structure is formed so that the c-axis is substantially parallel to the surface of the substrate.
A method for manufacturing a Hall element. A manufacturing method of the Hall element according to claim 6,
In the operation layer forming step, the operation layer is formed so that the two-dimensional electron gas concentration in the two-dimensional electron gas region is 2 × 10 ¹² / cm ³ or less.
A method for manufacturing a Hall element. A manufacturing method of the Hall element according to claim 6 or 7,
The operation layer forming step includes
A removal step of forming a cross-shaped portion having a substantially cross shape in plan view by removing a part of the operation layer;
Further comprising
In the electrode forming step,
The input electrode is formed on each of the two first tip portions facing each other of the cross-shaped portion, and the output electrode is formed on each of the two second tip portions different from the first tip portion. ,
A method for manufacturing a Hall element. A method of manufacturing a magnetoresistive element,
A GaN layer forming step of epitaxially forming a GaN layer on a predetermined substrate;
An AlGaN layer forming step of epitaxially forming an AlGaN layer on the GaN layer;
An operation layer forming step of forming an operation layer for forming a heterojunction structure between the GaN layer and the AlGaN layer,
Forming an electrode on each of the opposing ends of the surface of the working layer and forming a plurality of short-circuit electrodes between the terminal electrodes; and
With
As the substrate, either a single crystal substrate of hexagonal material selected from GaN, AlN, AlGaN, ZnO, α-SiC whose surface is m-plane or a-plane, or sapphire single-crystal substrate whose surface is r-plane Use
In the operation layer forming step, the operation layer whose crystal structure is a wurtzite structure is formed so that the c-axis is substantially parallel to the surface of the substrate.
A method of manufacturing a magnetoresistive effect element. A method for producing a magnetoresistive element according to claim 9,
In the operation layer forming step, the operation layer is formed so that the two-dimensional electron gas concentration in the two-dimensional electron gas region is 2 × 10 ¹² / cm ³ or less.
A method of manufacturing a magnetoresistive effect element.

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