JP2003218423A - Laminated compound semiconductor structure and magnetic sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To industrially provide a Hall element that is high in sensitivity, low in power consumption, and excellent in temperature characteristic by making possible the steady supply of a quantum well type compound semiconductor laminate having high electron mobility, a high sheet resistance, and a superior temperature characteristic. <P>SOLUTION: A laminated compound semiconductor structure is constituted by respectively laminating first and second compound semiconductor layers 12 and 14 composed of at least two kinds of elements selected from among Al, Ga, In, As, and P and Sb element upon the upper and lower surfaces of a compound semiconductor active layer 13 having a composition expressed by In<SB>x</SB>Ga<SB>1-x</SB>As<SB>y</SB>Sb<SB>1-y</SB>(0.8≤x≤1.0 and 0.8≤y≤1.0). The semiconductor layers 12 and 14 are formed so that the layers 12 and 14 may have wide band gaps as compared with the active layer 13 and resistance values which are 5 times or more as high as that of the active layer 13. In addition, the differences in lattice constant between the compound semiconductor layers 12 and 14 and active layer 13 may fall within the range of 0.0-1.2%. Moreover, the thickness of the active layer 13 is set within the range of 30-100 nm. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compound semiconductor laminated structure and a magnetic sensor, and more particularly to a quantum well type compound semiconductor laminated body having high electron mobility and sheet resistance and excellent temperature characteristics, The present invention also relates to a magnetic sensor having high sensitivity, low power consumption, and excellent temperature characteristics, which is configured using the magnetic sensor.

[0002]

2. Description of the Related Art In recent years, magnetic sensors have been widely used in technical fields such as portable devices and automobiles, and in such technical fields, magnetic sensors having low power consumption, high sensitivity, and excellent temperature characteristics are used. A sensor is required, and particularly when it is used for a mobile device such as a mobile phone, low power consumption is extremely important.

In general, the main characteristics of the Hall element that constitutes the magnetic sensor are strongly controlled by the characteristics of the semiconductor material. For example, sensitivity is proportional to the electron mobility of semiconductor materials,
Since the power consumption decreases as the input resistance of the element increases,
The larger the sheet resistance of the semiconductor material, the smaller it becomes.

Conventional Hall elements include compound semiconductors having a high electron mobility, particularly InAs, InSb, and GaAs.
However, the Hall element made of InSb or InAs has a good sensitivity, but has a disadvantage of poor temperature characteristics and power consumption characteristics. Although it is known that the temperature characteristics of the Hall element can be improved by doping InAs with Si, other element characteristics such as sensitivity characteristics and power consumption characteristics are not satisfactory. Furthermore, GaAs
The Hall element made of the above material has good temperature characteristics and power consumption characteristics, but has a drawback that the sensitivity of the element is low.

Regarding such a problem, Japanese Patent No. 306
No. 9545, a first compound semiconductor layer, an InAs layer as an active layer formed thereon, and I
When a laminated body is formed with the high resistance second compound semiconductor layer formed on the upper surface of the nAs layer, a quantum well type potential is formed in the InAs active layer, and the quantum effect is exerted to cause conduction in the active layer. It is described that the mobility of electrons to be generated and the sheet resistance are increased, and a laminate having good temperature characteristics can be formed.

Further, Japanese Patent No. 2793440 discloses that
When a laminated body structure including a quantum well type compound semiconductor similar to that described above is adopted for the Hall element structure, high sensitivity is obtained,
It is also described that a Hall element having a large input resistance and excellent temperature characteristics can be formed.

[0007]

However, the electron mobility of the compound semiconductor material itself and the electron mobility of the compound semiconductor material are required in order to keep the sensitivity and resistance of the Hall element adopting such a compound semiconductor laminated structure within a predetermined design range. It is required to keep the sheet resistance value within a certain range with good reproducibility, but it is difficult to control these physical property values. Therefore, it is industrially possible to use the Hall element using the quantum well type compound semiconductor laminated body. There was a problem that production was difficult.

The present invention has been made in view of the above problems, and an object thereof is to improve the reproducibility of physical property control of a quantum well type compound semiconductor laminated body,
It enables stable supply of quantum well compound semiconductor laminates with high electron mobility and sheet resistance and excellent temperature characteristics, which results in high sensitivity, low power consumption, and excellent temperature characteristics. It is to enable industrial provision of Hall elements.

[0009]

In order to achieve such an object, the present invention provides a first compound semiconductor layer, an active layer, and a second compound semiconductor layer on a substrate. And a compound semiconductor layer, wherein each of the first and second compound semiconductor layers is at least one of five kinds of Al, Ga, In, As, and P. a compound semiconductor layer composed of the two elements and Sb, the active _{layer, in x Ga 1-x as} y Sb
_1-y (0.8 ≤ x ≤ 1.0, 0.8 ≤ y ≤ 1.0), wherein each of the first and second compound semiconductor layers is a compound semiconductor Compared with the active layer, it has a wide bandgap and a resistance value of at least 5 times or more, and the lattice constant difference between the first and second compound semiconductor layers and the active layer is both 0. It is set in the range of 0 to 1.2%, and the active layer has a layer thickness of more than 30 nm and less than 100 nm.

The invention described in claim 2 is the same as claim 1.
In the compound semiconductor laminated structure described in (3), a third compound semiconductor layer of GaAs is laminated on the second compound semiconductor layer.

The invention described in claim 3 is the same as claim 1.
Alternatively, in the compound semiconductor laminated structure according to the aspect 2, the compound semiconductor forming the active layer is InAs.

Furthermore, the invention according to claim 4 is the same as claim 1.
In the compound semiconductor laminated structure according to any one of 1 to 3, the composition of the first and second compound semiconductor layers is Al.
_Z Ga _1-Z As _Y Sb _1-Y (0.0 ≦ Z ≦ 1.0,
0.0 ≦ Y ≦ 0.3).

The invention described in claim 5 is a magnetic sensor, which is characterized in that an electrode is provided in the active layer of the compound semiconductor laminated structure according to any one of claims 1 to 4.

According to a sixth aspect of the present invention, there is provided a mobile device including the magnetic sensor according to the fifth aspect.

Further, the invention described in claim 7 is the same as claim 6.
In the mobile device described in (1), the mobile device is a mobile phone.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram for explaining a constitutional example of a compound semiconductor laminated structure of the present invention, in which 11 is a substrate, 12 is a first compound semiconductor layer, 13 is an active layer made of a compound semiconductor, and , 14 are second compound semiconductor layers, and these compound semiconductor layers 12 to 14 are sequentially laminated on the substrate 11. In addition, in order to prevent deterioration of the surface of the second compound semiconductor layer 14 due to oxidation, the second compound semiconductor layer 14
The third compound semiconductor layer may be provided on the compound semiconductor layer 14.

Here, the first compound semiconductor layer 12 and the second compound semiconductor layer 14 are both multi-element compound semiconductor layers composed of three or more kinds of elements.
Containing Al as a constituent element, and Al, Ga, In, A
A high-resistance compound semiconductor layer composed of two or more elements selected from the group s and P, and in particular, A
is preferably _{l Z Ga 1-Z As Y} Sb 1-Y compound semiconductor having the composition expressed in. The composition ratio is preferably 0.0 ≦ Z ≦ 1.0 and 0.0 ≦ Y ≦ 0.3, and more preferably 0.4 ≦ Z ≦ 1.0.
0.0 ≦ Y ≦ 0.15, more preferably 0.4
5 ≦ Z ≦ 1.0 and 0.0 ≦ Y ≦ 0.12.

The thickness of the first compound semiconductor layer 12 is usually 150 nm to 1 μm, and 300 nm to 700 nm.
It is preferably within the range. This is because, in consideration of the actual device formation process, the thinner the first compound semiconductor layer 12 is, the easier the process is, which is a great industrial advantage. The thickness of the second compound semiconductor layer 14 is usually 5 nm to 100 nm, and 30 nm to 7 nm.
It is preferably in the range of 0 nm.

These first and second compound semiconductor layers 1
The resistance values of 2 and 14 are required to be at least 5 times or more the resistance value of the active layer 13, preferably 100 times or more, and more preferably 1000 times or more. It Further, the band gap of these layers 12 and 14 needs to be wider than the band gap of the active layer 13, and is usually several times or more the band gap of the active layer 13.

Examples of the compound semiconductor constituting the active layer _{13, In x Ga 1-x} As y Sb 1 -y (0.8 ≦ x ≦
1.0, 0.8 ≦ y ≦ 1.0) and InAs are preferable examples, and the composition when using In _x Ga _1-x As _y Sb _1-y is 0.88 ≦ x ≦ 1.0. And 0.82 ≦
It is preferable that y ≦ 1.0, and 0.9 ≦ x ≦ 1.
It is more preferable that 0 and 0.9 ≦ y ≦ 1.0.

The thickness of the active layer 13 is set to be thicker than 30 nm and thinner than 100 nm, preferably 35 n.
m or more and 90 nm or less, more preferably 40 nm
It is 70 nm or less. This is because when the thickness of the active layer 13 becomes thin, the first and second compound semiconductor layers 12 and 14 are formed.
The electron mobility and the sheet resistance fluctuate greatly due to the Sb composition variation, and it becomes difficult to manufacture industrially. On the other hand, when the Sb composition becomes too thick, the electron mobility itself decreases, and the first and second Of the compound semiconductor layers 12 and 14 of
This is because variations in the electron mobility and the sheet resistance due to variations in the composition become large and it becomes difficult to industrially manufacture.

First and second compound semiconductor layers 12, 14
The lattice constant of is set so that the lattice constant difference with respect to the lattice constant of the active layer 13 is 0.0% to 1.2%, preferably 0.1% to 1.0%, and more preferably ,
The range is 0.2% to 0.9%. Here, the lattice constant of each of these compound semiconductor crystals depends on the elemental composition of the layers according to the so-called “Vegaard's law”, so that the composition of each layer is optimized so that the mutual lattice constant difference is optimal. It will be decided. If the lattice constants of the first and second compound semiconductor layers 12 and 14 are too large or too small with respect to the lattice constant of the active layer 13, the first and second
Due to the compositional variation of Sb in the compound semiconductor layers 12 and 14, the characteristics such as electron mobility will vary greatly.

When the third compound semiconductor layer is provided on the second compound semiconductor layer 14, the material is preferably GaAs, GaAsSb or the like. In particular,
When GaAs is used, when the compound semiconductor laminated structure of the present invention is formed into an element, variations in element characteristics tend to be small. The thickness of the GaAs layer in this case is usually 0.5 nm to 50 nm, preferably 3 nm to 3 nm.
It is 0 nm, more preferably 6 nm to 15 nm.

Here, there is no particular limitation on the substrate 11, but it is selected in consideration of the lattice constant of the compound semiconductor layer 12 to be laminated thereon, for example, GaAs, GaP,
Compound semiconductor wafers such as InP and InSb, Si wafers and the like are preferable examples. Further, the plane orientation in which the crystal is grown is preferably (100), (111), (110) or the like.

In the compound semiconductor laminated structure having the structure shown in FIG. 1, electric characteristics such as electron mobility and sheet resistance can be stably obtained. This is because, in the compound semiconductor laminated structure having such a structure, as described above,
Even if there is a composition variation of Sb that is necessarily contained in the first and second compound semiconductor layers because the layer thickness and the lattice constant (that is, the composition) of each layer have an optimized relationship with each other, Because it does not dramatically change the electrical characteristics.

That is, according to the study by the present inventor, it is difficult to obtain highly reproducible electron mobility and sheet resistance in the conventional quantum well type compound semiconductor laminated structure. In addition, it is difficult to control Sb that is always included in the second compound semiconductor layer, and a change in Sb composition that occurs, which causes a dramatic change in characteristics such as electron mobility, is stable. In order to obtain the characteristics, it is necessary to adopt a structure that reduces the influence of the Sb composition variation on the electrical characteristics.

Further, in Japanese Patent No. 3069545 and Japanese Patent No. 2793440, it is said that the thickness of the sensor layer such as InAs is preferably 20 nm or less in order to form a Hall sensor having a quantum effect.
The present inventor designed the thickness of the sensor layer (active layer) to be thicker than 20 nm, and further, set the lattice constants of the first and second compound semiconductor layers to 0.0% to 1.2% of the lattice constant of the active layer. The compound semiconductor laminated structure of the present invention is constructed by finding that the fluctuation of the electron mobility and the sheet resistance caused by the fluctuation of the Sb composition of the compound semiconductor layer is suppressed by setting the ratio to be in the range of%. is there.

In the compound semiconductor laminated structure having the structure shown in FIG. 1, the thickness of the active layer 13 and the difference in lattice constant between the first and second compound semiconductor layers 12 and 14 and the active layer 13 (lattice mismatch). It is considered that each of the degrees has an optimum value for the following reason.

That is, the compound semiconductor layer is composed of Sb in the layer.
It has been experimentally confirmed that the larger the composition, the better the crystallinity, but the larger the Sb composition in the layer, the larger the degree of lattice mismatch with the crystal forming the active layer 13. . At this time, if the thickness of the active layer 13 is thin, 1
%, The electron mobility of the active layer 13 increases with the increase of the Sb composition in the compound semiconductor layer, and as a result, the sheet resistance also decreases, resulting in a variation in characteristics. Will become bigger.

On the other hand, when the active layer 13 is thick,
The lattice mismatch is affected even by about 1%, stress is added to the crystal as the Sb composition in the compound semiconductor layer increases, and the electron mobility decreases. As a result, the electron mobility in the active layer 13 is It becomes almost constant regardless of the Sb composition inside, and the sheet resistance also falls within a certain range. Further, when the active layer 13 has a very small thickness of 20 nm or less, Sb composition fluctuations, film thickness fluctuations, and the like become prominent, so that highly reproducible electrical characteristics cannot be obtained.

The thickness of the first compound semiconductor layer 12 is about 306945 gazettes and 279344 gazettes.
In JP-A-0, it is described that the thickness is preferably 1 μm in order to obtain the quantum effect, but the reason why such a thick layer is not necessary in the present invention is that the layer thickness of the active layer 13 is set thick. It is thought that it is because there is.

When a magnetic sensor is constructed by using the compound semiconductor laminated structure of the present invention having the above-mentioned construction, a magnetic sensor having high sensitivity, high input resistance and good temperature characteristics can be stably and reproducibly produced. It can be manufactured well. Further, since such a magnetic sensor consumes less power than a magnetic sensor having a conventional configuration, it is suitable for use in mobile devices such as mobile phones.

FIG. 2 is a view for explaining a structural example of the magnetic sensor of the present invention constituted by using the compound semiconductor laminated structure having the constitution shown in FIG. 1, in which 21 is a substrate and 22 is a first compound. A semiconductor layer, 23 an active layer made of a compound semiconductor,
24 is a second compound semiconductor layer, and 25 is a third compound semiconductor layer. Parameters such as the composition and film thickness of the compound semiconductor layers shown in 22 to 25 are the same as those described above with reference to FIG. The laminated body composed of 22 to 25 is referred to as a "semiconductor thin film". Further, 26 is a metal electrode layer, and 27 is a protective layer.

The metal electrode layer 26 is usually an ohmic electrode, preferably an ohmic contact with the sensor layer (active layer 23), and the material thereof is AuGe.
A well-known multilayer electrode such as / Ni / Au or a single-layer metal may be used. Further, as a material forming the protective layer 27, SiN, SiO ₂ or the like is preferable.

The magnetic sensor of the present invention includes a Hall element, a magnetoresistive element and the like.

Examples of the present invention will be specifically described below.

Example 1 On a GaAs substrate with a diameter of 2 inches, 600 nm Al _0.55 Ga was formed as a first compound semiconductor layer by a molecular beam epitaxy (MBE) method.
_0.45 AsSb, 50 nm InAs as an active layer,
As the second compound semiconductor layer, Al _{0 . 55} G
a _0.45 AsSb, 6n as the third compound semiconductor layer
m GaAsSb was sequentially formed.

The composition of Sb is calculated from Vegard's law based on the precise lattice constant obtained by the high-resolution X-ray diffraction method by the four-crystal method using Ge (220) single crystal, and the electric mobility such as electron mobility is calculated. The characteristics were evaluated by measuring the Hall effect by the van der Pauw method.

Table 1 summarizes the thus obtained lattice constant difference, electron mobility and sheet resistance for each Sb composition.

[0041]

[Table 1]

As can be seen from this table, the first and second
Sb composition (Sbx = Sb / (Sb
+ As)) was changed from 0.885 to 1.000 and the electric characteristics were stable, and it was confirmed that the Sb composition fluctuation had a small effect on the electric characteristics. That is, a wide S
In the range of bx = 0.885 to 1.00, the electron mobility is within the range of the average value ± 9%, and the sheet resistance is also within the average value ±.
It is in the range of 31%.

The specifications of Hall devices currently on the market vary, but for example, the center value of the resistance is ± 40.
%, The center value is about ± 45% with respect to sensitivity, but the laminated structure of the present embodiment has electron mobility proportional to sensitivity and sheet resistance proportional to resistance within this range. It can be judged that there is little variation. In normal industrial production, Sbx can be operated within the range of the central value ± 0.04. Sbx = 0.902-
In the range of 0.983, the average electron mobility is ± 8%.
And the sheet resistance also fall within the range of the average value ± 20%, and it was confirmed that the compound semiconductor laminated structure can be industrially produced with a high yield.

(Comparative Example 1) 2 inch diameter GaAs substrate
In addition, by the molecular beam epitaxy (MBE) method,
600 nm Al as compound semiconductor layer_0.55Ga
_0.45AsSb, 15 nm InAs as an active layer,
60 nm Al as the second compound semiconductor layer _0.55G
a_0.45AsSb, 6n as third compound semiconductor layer
m GaAsSb was sequentially formed.

The composition of Sb was calculated from Vegard's law based on the precise lattice constant obtained by the high-resolution X-ray diffraction method by the four-crystal method using Ge (220) single crystal, and the electric mobility such as electron mobility was calculated. The characteristics were evaluated by measuring the Hall effect by the van der Pauw method.

Table 2 summarizes the lattice constant difference thus obtained, the electron mobility and the sheet resistance for each composition of Sb.

[0047]

[Table 2]

Sbx in the first and second compound semiconductor layers
The electrical characteristics greatly fluctuate according to the change of Sbx =
When viewed in the range of 0.890 to 1.00, the electron mobility is in the range of ± 32% of the average value, and the sheet resistance is in the range of ± 82% of the average value, which is far from the specifications of the commercially available Hall element. .

In ordinary industrial production, Sbx can be operated within the range of the center value ± 0.04. However, even in the range of Sbx = 0.890 to 0.967, the electron mobility is in the range of ± 18% of the average value, and the sheet resistance is in the range of ± 63% of the average value, which makes industrial production difficult. I can confirm.

3 and 4 are diagrams showing the evaluation results of the dependence of electron mobility and sheet resistance on the difference in lattice constant, together with the evaluation results of Example 1. FIG. 3 shows the lattice constant of electron mobility. FIG. 4 shows the dependence of the sheet resistance on the difference in lattice constant.

As can be seen from these figures, the change in both characteristics is small with respect to the change in Sbx in Example 1, while it is extremely large in Comparative Example 1. Further, comparing the sheet resistance obtained in Example 1 with the maximum values (280Ω, 21000 cm ² / Vs) described in Japanese Patent Nos. 3069545 and 2793440,
In a wide range of Sbx = 0.918 to 0.983, the electron mobility is equivalent or higher, the sheet resistance is as large as 16% to 70%, and the power consumption is low. It was confirmed to be suitable for.

(Example 2) GaAs substrate having a diameter of 2 inches
In addition, by the molecular beam epitaxy (MBE) method,
600 nm Al as compound semiconductor layer_0.55Ga
_0.45AsSb, 70 nm InAs as an active layer,
60 nm Al as the second compound semiconductor layer _0.55G
a_0.45AsSb, 6n as third compound semiconductor layer
m GaAsSb was sequentially formed.

The composition of Sb was calculated from Vegard's law based on the precise lattice constant obtained by the high resolution X-ray diffraction method by the four-crystal method using Ge (220) single crystal, and the electric mobility such as electron mobility was calculated. The characteristics were evaluated by measuring the Hall effect by the van der Pauw method.

Table 3 summarizes the lattice constant difference thus obtained, the electron mobility and the sheet resistance for each composition of Sb.

[0055]

[Table 3]

As shown in this table, it was confirmed that the change in characteristics was small even if Sbx was changed. Broad Sbx
= 0.886 to 0.999, the electron mobility is within the range of ± 11% of the average value, and the sheet resistance is also within the average value ±.
It is in the range of 28%. According to the specifications of commercially available Hall elements, the central resistance is ± 40%, and the central sensitivity is ± 45%.
Although it is a degree, both the electron mobility proportional to the sensitivity and the sheet resistance proportional to the resistance are within this range, and it can be determined that these variations are small.

In the ordinary industrial production, Sb
The x can be operated within the range of the central value ± 0.04. Looking in the range of Sbx = 0.901 to 0.980,
The electron mobility is within the range of ± 9% or less in average value, and the sheet resistance is also in the range of ± 20% in average value, and it is confirmed that the compound semiconductor laminated structure can be industrially produced with high yield. did it.

(Example 3) GaAs substrate having a diameter of 2 inches
In addition, by the molecular beam epitaxy (MBE) method,
600 nm Al as compound semiconductor layer_0.55Ga
_0.45AsSb, 35 nm InAs as an active layer,
60 nm Al as the second compound semiconductor layer _0.55G
a_0.45AsSb, 6n as third compound semiconductor layer
m GaAsSb was sequentially formed.

The composition of Sb is calculated from the Vegard's law based on the precise lattice constant obtained by the high resolution X-ray diffraction method by the four-crystal method using Ge (220) single crystal, and the electric mobility such as electron mobility is calculated. The characteristics were evaluated by measuring the Hall effect by the van der Pauw method.

Table 4 summarizes the lattice constant difference thus obtained, the electron mobility and the sheet resistance for each composition of Sb.

[0061]

[Table 4]

As shown in this table, it was confirmed that the characteristic change was small even if Sbx was changed. Wide Sbx =
In the range of 0.892 to 1.00, the electron mobility is an average value ±
It is within the range of 14%, and the sheet resistance is an average value ± 48.
It is in the range of%. According to the specifications of commercially available Hall elements, the resistance has a central value of ± 40% and the sensitivity has a central value of ± 45%. In the laminated structure of this example, the electron mobility proportional to the sensitivity is within the specifications, but the sheet resistance proportional to the resistance is slightly beyond the range of the specifications.

In the usual industrial production, Sb
x can be operated within the range of the central value ± 0.04. Looking at Sbx = 0.904 to 0.980,
Since the electron mobility is within the range of ± 10% of the average value and the sheet resistance is also within the range of ± 36% of the average value, it can be confirmed that it is within the specifications of the commercially available Hall element and industrial production is possible.

(Embodiment 4) GaAs substrate having a diameter of 2 inches
In addition, by the molecular beam epitaxy (MBE) method,
600 nm Al as compound semiconductor layer_0.45Ga
_0.55AsSb, 50 nm InAs as an active layer,
60 nm Al as the second compound semiconductor layer _0.45G
a_0.55AsSb, 6n as third compound semiconductor layer
m GaAsSb was sequentially formed.

The composition of Sb was calculated from Vegard's law based on the precise lattice constant obtained by the high-resolution X-ray diffraction method by the four-crystal method using Ge (220) single crystal, and the electric mobility such as electron mobility was calculated. The characteristics were evaluated by measuring the Hall effect by the van der Pauw method.

Table 5 shows a summary of the thus obtained lattice constant difference, electron mobility and sheet resistance for each Sb composition.

[0067]

[Table 5]

As can be seen from this table, even if Sbx is changed, the characteristic change is small, and a wide Sbx = 0.888-1.
In the range of 00, the electron mobility is in the range of average value ± 9%, and the sheet resistance is also in the range of average value ± 30%. According to the specifications of commercially available Hall elements, the resistance has a central value of ± 40% and the sensitivity has a central value of ± 45%, but both the electron mobility proportional to the sensitivity and the sheet resistance proportional to the resistance are within this range. It can be judged that these variations are small.

In ordinary industrial production, Sb
The x can be operated within the range of the central value ± 0.04. Looking in the range of Sbx = 0.897−0.984,
The electron mobility is within the range of ± 8% or less in average value, and the sheet resistance is also in the range of ± 22% in average value.
It was confirmed that the compound semiconductor laminated structure can be produced with a high yield.

(Example 5) GaAs substrate having a diameter of 2 inches
In addition, by the molecular beam epitaxy (MBE) method,
600 nm Al as compound semiconductor layer_0.65Ga
_0.35AsSb, 50 nm InAs as an active layer,
60 nm Al as the second compound semiconductor layer _0.65G
a_0.35AsSb, 6n as third compound semiconductor layer
m GaAsSb was sequentially formed.

The composition of Sb was calculated from Vegard's law based on the precise lattice constant obtained by the high resolution X-ray diffraction method by the four-crystal method using Ge (220) single crystal, and the electric mobility such as electron mobility was calculated. The characteristics were evaluated by measuring the Hall effect by the van der Pauw method.

Table 6 shows a summary of the thus obtained lattice constant difference, electron mobility and sheet resistance for each composition of Sb.

[0073]

[Table 6]

As can be seen from this table, even if Sbx is changed, the characteristic change is small, and a wide range of Sbx = 0.886 to 1.
In the range of 00, the electron mobility is in the range of average value ± 10%, and the sheet resistance is also in the range of average value ± 34%. According to the specifications of commercially available Hall elements, the resistance has a central value of ± 40% and the sensitivity has a central value of ± 45%, but both the electron mobility proportional to the sensitivity and the sheet resistance proportional to the resistance are within this range. Therefore, it can be determined that the variation is small.

In ordinary industrial production, Sb
The x can be operated within the range of the central value ± 0.04. Looking in the range of Sbx = 0.902 to 0.988,
The electron mobility is within the range of ± 8% of the average value, and the sheet resistance is also within the range of ± 28% of the average value.
It was confirmed that the compound semiconductor laminated structure can be produced with a high yield.

Example 6 On a GaAs substrate having a diameter of 2 inches, a first compound semiconductor layer of Al _0.65 Ga having a thickness of 600 nm was formed by a molecular beam epitaxy (MBE) method.
_0.35 AsSb, 50 nm In as active layer
_0.97 Ga _0.03 As _0.98 Sb _0.02 , second
60 nm Al _0.65 Ga as the compound semiconductor layer of
_0.35 AsSb, 6 nm as third compound semiconductor layer
Of GaAsSb were sequentially formed.

The composition of Sb was calculated from the Vegard's law based on the precise lattice constant obtained by the high-resolution X-ray diffraction method by the four-crystal method using Ge (220) single crystal, and the electric mobility such as electron mobility was calculated. The characteristics were evaluated by measuring the Hall effect by the van der Pauw method.

Table 7 summarizes the lattice constant difference, electron mobility and sheet resistance thus obtained for each Sb composition.

[0079]

[Table 7]

As can be seen from this table, even if Sbx changes, the characteristic change is small, and the wide Sbx = 0.905-
In the range of 0.992, the electron mobility is in the range of average value ± 8%, and the sheet resistance is also in the range of average value ± 25%. According to the specifications of commercially available Hall elements, the resistance has a central value of ± 40% and the sensitivity has a central value of ± 45%, but both the electron mobility proportional to the sensitivity and the sheet resistance proportional to the resistance are within this range. Therefore, it can be determined that the variation is small.

In the ordinary industrial production, Sb
The x can be operated within the range of the central value ± 0.04. Looking in the range of Sbx = 0.905 to 0.980,
The electron mobility is within the range of ± 8% or less in average value, and the sheet resistance is also in the range of ± 22% in average value.
It was confirmed that the compound semiconductor laminated structure can be produced with a high yield.

Example 7 Next, a Hall element, which is a magnetic sensor similar to that shown in FIG. 2, was formed on the laminated substrate formed in Example 1 by photolithography, and the Hall element characteristics were measured. . The electrodes are T
An i layer of 100 nm and an Au layer of 600 nm were used by continuous vapor deposition. Hall element chip size is 360μm x 360μ
m, and the length of the magnetic sensing part (length between facing electrodes) is 95μ
m and the width is 35 μm. 50mT for this Hall element
The sensitivity of the Hall element was measured by applying an input voltage of 3 V in the magnetic field. The measurement was performed on the element in the center of the substrate.

Table 8 shows a summary of the sensitivity and the lattice constant difference of the input resistance thus measured.

[0084]

[Table 8]

As shown in this table, Sbx = 0.85
In the range of ˜1.00, the average sensitivity was 111 mV and the input resistance was 891 ohm. This sensitivity is the same as normal GaAs
It was confirmed that the device had a sensitivity twice as high as that of the Hall element using, and an element resistance equal to or more than the example described in Japanese Patent No. 2793440, and was a highly sensitive and low power consumption element. Also, regarding the temperature characteristic, the patent No. 2793
It was confirmed that the device had the same level as the device described in Japanese Patent No. 440.

The variation in sensitivity is within the range of ± 11% of the average value, and the sheet resistance is also within the range of ± 34% of the average value. According to the specifications of commercially available Hall elements, the resistance has a central value of ± 40% and the sensitivity has a central value of ± 45%, but both the electron mobility proportional to the sensitivity and the sheet resistance proportional to the resistance are within this range. Therefore, it can be determined that the variation is small.

In the usual industrial production, Sb
x can be operated within the range of the central value ± 0.04, and when viewed in the range of Sbx = 0.902 to 0.983,
The sensitivity was within the range of ± 7% in average value, and the input resistance was in the range of ± 19% in average value, and it was confirmed that the quantum well type Hall sensor can be industrially produced with high yield. .
In addition, it was confirmed that the magnetic sensor of this example has low power consumption and is suitable for use in mobile devices such as mobile phones.

(Comparative Example 2) In Table 9, a Hall element was formed in the same manner as in Example 7 using the laminated body formed in Comparative Example 1,
The results of measuring the Hall element characteristics under the same conditions are summarized.

[0089]

[Table 9]

As can be seen from this table, Sbx = 0.89
In the range of 0 to 1.00, the average value of sensitivity is 116 mV, the average value of input resistance is 1273 ohms, the variation of sensitivity is ± 35% on average, and the variation of input resistance is ± 84% on average. Therefore, the spec of the Hall element on the market is largely deviated.

In ordinary industrial production, Sbx can be operated within the range of the center value ± 0.04.
Even in the range of Sbx = 0.888-0.967, the sensitivity is in the range of ± 24% and the input resistance is in the range of ± 62%.
It was confirmed that the industrial production was difficult. The in-plane resistance distribution and sensitivity distribution are shown in Example 7.
It showed a markedly worse tendency than

Example 8 Table 10 shows the results of measuring Hall element characteristics under the same conditions by forming Hall elements in the same manner as in Example 7 using the laminates formed in Examples 2-6. , And the input resistance and their variations) are summarized.

[0093]

[Table 10]

In any of these Hall elements,
It has been confirmed that the specifications of commercially available Hall elements are almost satisfied, and that quantum well Hall sensors can be industrially produced with high yield. Moreover, the sensitivity of these elements is twice or more than that of a normal hall element using GaAs, and it was confirmed that the element has high sensitivity and low power consumption.

(Example 9) GaAs substrate having a diameter of 2 inches
In addition, by the molecular beam epitaxy (MBE) method,
600 nm Al as compound semiconductor layer_0.55Ga
_0.45AsSb, 50 nm InAs as an active layer,
60 nm Al as the second compound semiconductor layer _0.55G
a_0.45AsSb, 6n as the third compound semiconductor layer
m GaAs was sequentially deposited.

The composition of Sb was calculated from Vegard's law based on the precise lattice constant obtained by the high resolution X-ray diffraction method by the four-crystal method using Ge (220) single crystal, and the electric mobility such as electron mobility was calculated. The characteristics were evaluated by measuring the Hall effect by the van der Pauw method.

Table 11 summarizes the lattice constant difference, electron mobility and sheet resistance thus obtained for each Sb composition.

[0098]

[Table 11]

As can be seen from this table, even if the Sb composition in the first and second compound semiconductor layers changes, the characteristic change is small, and the electron mobility is wide in the wide range of Sbx = 0.886 to 1.00. The average value is within the range of ± 9%, and the sheet resistance is also within the range of the average value ± 31%. Both variations in electron mobility proportional to sensitivity and sheet resistance proportional to resistance are within the range of variations in sensitivity and input resistance of commercially available Hall elements, and it can be determined that the variations are small.

In ordinary industrial production, Sbx can be operated within the range of the center value ± 0.04.
When viewed in the range of Sbx = 0.904 to 0.984, the electron mobility is within the range of the average value ± 8%, and the sheet resistance is also within the range of the average value ± 20%. It was confirmed that the compound semiconductor laminated structure could be produced at a high rate, and the same result as the laminated structure in the case where the third compound semiconductor layer was composed of GaAsSb was obtained.

(Example 10) Table 12 summarizes the results of measuring Hall element characteristics by forming a magnetic sensor (Hall element) similar to that shown in FIG. 2 using the photolithography method, as in Example 7. It is a thing.

[0102]

[Table 12]

As shown in this table, Sbx = 0.886
In the range of ˜1.00, the average sensitivity was 111 mV and the input resistance was 897 ohm. This sensitivity is the same as normal GaAs
It was confirmed that the sensitivity was more than twice as high as that of the Hall element using, and it was a highly sensitive and low power consumption element.

The variation in sensitivity is within the range of ± 9%, and the sheet resistance is within the range of average value ± 32%.
This result is better than the case where the third compound semiconductor layer is made of GaAsSb (Example 7). According to the specifications of commercially available Hall elements, the resistance has a central value of ± 40% and the sensitivity has a central value of ± 45%, but both the electron mobility proportional to the sensitivity and the sheet resistance proportional to the resistance are within this range. Therefore, it can be judged that the variation is small.

In the ordinary industrial production, Sb
Since x can be operated within the range of the center value ± 0.04, the sensitivity is within the range of the average value ± 8% in the range of Sbx = 0.902 to 0.983. The resistance is also within the range of ± 20% of the average value, and the variation is smaller than that in the case where the third compound semiconductor layer is made of GaAsSb, and the quantum well Hall sensor can be industrially produced at a high yield. I was able to confirm that.

[0106]

As described above, according to the present invention,
The laminated structure of the compound semiconductor is made of Al, Ga, In, As.
And first and second compound semiconductor layers composed of Sb and at least two elements out of five elements, and In _x Ga
_{1-x As y Sb 1-} y (0.8 ≦ x ≦ 1.0,0.8
≦ y ≦ 1.0) and an active layer of a multi-element compound semiconductor having a composition represented by the formula: ≦ y ≦ 1.0) are laminated, and the lattice constant difference between the first and second compound semiconductor layers and the active layer is both 0.0 to 1. It is set to be within the range of 2%, and the active layer thickness is 30 to 100.
Since it is set in the range of nm, it becomes possible to enhance the reproducibility of the physical property control of the quantum well compound semiconductor laminated body, and it is possible to obtain a quantum well compound semiconductor having high electron mobility and sheet resistance and excellent temperature characteristics. This makes it possible to stably supply the laminated body, which makes it possible to industrially provide a magnetic sensor having high sensitivity, low power consumption, and excellent temperature characteristics.

[Brief description of drawings]

FIG. 1 is a diagram illustrating a configuration example of a compound semiconductor laminated structure of the present invention.

FIG. 2 is a diagram for explaining a configuration example of a magnetic sensor of the present invention.

FIG. 3 is a diagram for explaining the SB composition (Sbx) dependency of electron mobility of the compound semiconductor laminated structures shown in Example 1 and Comparative Example 1.

FIG. 4 is a diagram for explaining the SB composition (Sbx) dependency of the sheet resistance of the compound semiconductor laminated structures shown in Example 1 and Comparative Example 1.

[Explanation of symbols]

11, 21 substrate 12, 22 First compound semiconductor layer 13, 23 Active layer 14, 24 Second compound semiconductor layer 25 Third Compound Semiconductor Layer 26 Metal electrode layer 27 Protective layer

Claims (7)

[Claims] 1. A laminated structure of a compound semiconductor in which a first compound semiconductor layer, an active layer, and a second compound semiconductor layer are sequentially laminated on a substrate, wherein the first and second compound semiconductor layers are laminated. Each of the compound semiconductor layers is Al, G
a, an In, a compound semiconductor layer composed of at least two elements and Sb among the five As and P, the active _{layer, In x Ga 1-x As} y Sb
_1-y (0.8 ≦ x ≦ 1.0, 0.8 ≦ y ≦ 1.0), which is a compound semiconductor, wherein each of the first and second compound semiconductor layers comprises: Compared with the active layer, it has a wider bandgap and a resistance value of at least 5 times or more, and the difference in lattice constant between the first and second compound semiconductor layers and the active layer is both 0. It is set within a range of 0 to 1.2%, and the active layer has a layer thickness of more than 30 nm and less than 100 nm. 2. A GaA film is formed on the second compound semiconductor layer.
The compound semiconductor laminated structure according to claim 1, wherein the third compound semiconductor layer of s is laminated. 3. The compound semiconductor forming the active layer,
It is InAs, The compound semiconductor laminated structure of Claim 1 or 2 characterized by the above-mentioned. 4. The composition of the first and second compound semiconductor layers is Al _Z Ga _{1 -Z} As _Y Sb _1-Y (0.0 ≦ Z
≦ 1.0, 0.0 ≦ Y ≦ 0.3), Compound semiconductor laminated structure according to any one of claims 1 to 3. 5. A magnetic sensor comprising an active layer of the compound semiconductor laminated structure according to claim 1 provided with an electrode. 6. A mobile device comprising the magnetic sensor according to claim 5. 7. The mobile device according to claim 6, wherein the mobile device is a mobile phone.