JP2950243B2 - Magnetoresistive element and method of manufacturing the same - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a magnetoresistive element having a structure in which a semiconductor is sandwiched between electrodes, and a method of manufacturing the same.

[0002]

2. Description of the Related Art As such a conventional magnetoresistive element (hereinafter referred to as "MR element"), a corbino structure and a hole bar structure are known (Nikkei Electronics, March 22, 1976, 101). FIG. 2 is a schematic sectional view showing an MR element having a corbino structure. The MR element 50 having a corbino structure is obtained by sandwiching a semiconductor 52 between a center electrode 54 and a ring-shaped electrode 56. With the center electrode 54 as the center of the circle, the semiconductor 52 and the ring-shaped electrode 56
Are arranged on concentric circles. Since the corbino structure does not accumulate charges due to the Hall effect, a large magnetoresistance effect can be obtained. FIG. 3 is a schematic sectional view showing an MR element having a hole bar structure. The MR element 60 having the hole bar structure has a rod-shaped semiconductor 62 with both ends sandwiched between electrodes 64 and 66. Since the hole bar structure is a very simple structure, it is easy to manufacture.

The magnetoresistance effect of HgCdTe has been investigated by LN Korol 'et al. Using bulk crystals (Sov. Phys. Semicond.), Vol. 11, pp. 288, 197.
7 and 12, 275, 1978). According to their experimental results, a resistance change of 180 times was obtained at room temperature and a magnetic flux density of 1T. As for the MR element using HgCdTe and the method of manufacturing the same, a practically usable prior art is not disclosed as far as the inventor knows.

[0004]

However, the conventional MR element has the following problems. Since the corbino structure cannot use the planar process,
Difficult to manufacture. On the other hand, in the hole bar structure, the magnetoresistance effect is extremely small due to charges generated on the side surface of the semiconductor. In addition, HgCdTe cannot be put to practical use as an MR element because a structure and a manufacturing method for deriving its characteristics have not been established.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is easy to manufacture, and can prevent a reduction in the magnetoresistance effect due to charge accumulation.
It is an object of the present invention to provide an MR element suitable for a II-VI group semiconductor such as dTe and a method for manufacturing the same.

[0006]

In the MR element according to the present invention, a first electrode layer, a first semiconductor layer, a second electrode layer, a second semiconductor layer, and a third electrode layer are laminated in this order. And before
The first and second semiconductor layers are not in contact with each other, and the third electrode layer is in electrical contact with the first electrode layer without being in electrical contact with the second electrode layer. And the third electrode layer is in electrical contact with both side surfaces of the first and second semiconductor layers existing in a direction perpendicular to the laminating direction.

In other words, the first semiconductor layer is in contact with the second electrode layer below and the second semiconductor layer is in contact with the second electrode layer above,
The first or third electrode layer is in contact with the first semiconductor layer, the second semiconductor layer, and both side surfaces of the first and second semiconductor layers. The first electrode layer and the third electrode layer are conductive, and the first electrode layer, the third electrode layer, and the second electrode layer are not conductive. Here, by applying a voltage between the first electrode layer and the third electrode layer and the second electrode layer,
When a current flows through the first and second semiconductor layers, the directions of the currents flowing through the first and second semiconductor layers are opposite to each other. Therefore, when detecting a magnetic flux parallel to both side surfaces of these semiconductor layers and perpendicular to the laminating direction, the polarities of the Hall voltages generated in the first and second semiconductor layers are also opposite. Charges of different polarities are accumulated on the surfaces. However, since both side surfaces of these semiconductor layers are electrically short-circuited by the first and third electrode layers, the reduction of the magnetoresistance effect due to charge accumulation does not occur. Also,
The first and second semiconductor layers are made of HgCdTe, HgMnTe
Alternatively, by using these mixed crystals, a larger magnetoresistance effect can be obtained.

[0008] A method for manufacturing an MR element according to the present invention is a method for manufacturing an MR element according to the present invention, wherein the first electrode layer, the first semiconductor layer, the second electrode layer, Forming a second semiconductor layer sequentially, followed by the first semiconductor layer,
The second electrode layer, the second semiconductor layer is etched so as to remain in a stripe shape, subsequently, both sides of the second electrode layer present in a direction perpendicular to the stacking direction are etched, and then the second electrode layer is etched. The third electrode layer is formed.

The first and second electrode layers may be made of highly doped CdTe or HgTe, the first and second semiconductor layers may be made of HgCdTe, and the third electrode layer may be made of metal. In this case, one crystal growth step and a subsequent element formation step such as etching are performed, and it is not necessary to regrow the semiconductor crystal after the element formation step. In addition, since the element forming process also includes general photolithography, wet etching, and the like, it is a manufacturing method suitable for mass production. Also,
In the manufacturing method of the present invention, there is a step of removing a part of the second electrode layer by selective etching, which greatly contributes to simplification of the step. In addition, Mn,
At least one kind of Zn, Se, and S may be mixed in a small amount.

[0010]

FIG. 1 is a schematic sectional view showing an embodiment of an MR element according to the present invention. Hereinafter, description will be made based on this drawing.

The MR element 10 comprises an electrode layer 12, a semiconductor layer 1
4, the electrode layer 16, the semiconductor layer 18, and the electrode layer 20 are stacked in this order, and the semiconductor layers 14, 18 are in contact with each other.
In other words, both side surfaces 14a, 14b of the semiconductor layers 14, 18 in which the electrode layer 20 is in electrical contact with the electrode layer 12 without being in electrical contact with the electrode layer 16, and exists in the direction perpendicular to the laminating direction. , 18a and 18b are in electrical contact with the electrode layer 20.

The semiconductor layers 14 and 18 are made of HgCdTe. The electrode layers 12 and 16 are made of CdTe, HgTe or Hg
CdTe, and In is doped at a high concentration of about 10 ¹⁸ cm ⁻³ . The electrode layer 20 is In metal. MR
The element 10 is formed on a substrate 22 and has a stripe shape (elongated left and right when the MR element 10 is viewed from above in FIG. 1), and mainly detects a magnetic flux in a direction perpendicular to the drawing.

The semiconductor layer 14 is in contact with the electrode layer 16 below and the semiconductor layer 18 is in contact with the semiconductor layer 14. The electrode layer 12 is in contact with the semiconductor layer 14 below.
The electrode layer 20 is in contact with both side surfaces 14a,. The electrode layer 12 and the electrode layer 20 are conductive, and the electrode layers 12, 20 and the electrode layer 16 are not conductive. here,
When a current flows through the semiconductor layers 14 and 18 by applying a voltage between the electrode layers 12 and 20 and the electrode layer 16, the directions of the currents flowing through the semiconductor layers 14 and 18 are opposite to each other.
Therefore, when detecting a magnetic flux parallel to both side surfaces 14a,... Of the semiconductor layers 14, 18 and perpendicular to the lamination direction (that is, perpendicular to the drawing), the polarity of the Hall voltage generated in the semiconductor layers 14, 18 is also reversed. Therefore, charges of different polarities are accumulated on both side surfaces 14a,. However, since both side surfaces 14a,... Are electrically short-circuited by the electrode layers 12, 20, the reduction of the magnetoresistance effect due to the accumulation of charges does not occur.

Next, a method for manufacturing the MR element 10 will be described.

First, a single crystal GaAs is prepared as the substrate 22. Subsequently, the electrode layer 12, the semiconductor layer 14, the electrode layer 16, and the semiconductor layer 18 are sequentially formed on the substrate 22. That is, highly doped CdT is deposited on single crystal GaAs.
An e-layer or a HgTe layer, a HgCdTe layer, a heavily doped CdTe layer or a HgTe layer, and a total of four layers of a HgCdTe layer are sequentially crystal-grown. It can be formed in a series of processes in a HgCdTe growth apparatus. As the substrate 22, a single crystal such as Si, CdTe, or CdZnTe may be used.

Subsequently, for example, etching is performed in a stripe shape up to the electrode layer 12. Etching in a stripe shape means that the semiconductor layer 14 and the electrode layer 1 are viewed from above in FIG.
6 and the semiconductor layer 18, the semiconductor layer 14, the electrode layer 16
And that the semiconductor layer 18 is left elongated in the left-right direction.

Subsequently, the electrode layer 1 is formed by a selective etching method.
6 are etched on both side surfaces 16a and 16b. This step is for insulating the electrode layer 16 from the electrode layers 12 and 20. When the electrode layer 16 is made of CdTe, a selective etching method such as Parat etch (Journal of Vacuum Science and Technology (J. Vac)
uum Sci.Technol.), B9, 1625, 1991.
Year). When the electrode layer 16 is HgTe, Sporken etch (Applied Physics Letters (APPl. Phys. Lett.), Vol. 59, 81) is used as a selective etching method.
1991). Finally, the electrode layer 20 is formed by vapor deposition of In.

[0018]

According to the MR element of the present invention, the charges collected on both side surfaces of the first and second semiconductor layers by the Hall effect flow out through the first and third electrode layers.
It is possible to prevent a reduction in the magnetoresistance effect due to the accumulation of charges. Further, according to the manufacturing method of the present invention, an MR element can be easily manufactured by using a general planar process of lamination and etching. Further, according to the MR element and the method of manufacturing the same according to the present invention, the semiconductor layer is formed of Hg.
By using CdTe, HgMnTe or a mixed crystal thereof, a greater magnetoresistance effect can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing one embodiment of an MR element of the present invention.

FIG. 2 is a schematic sectional view showing a conventional MR element having a corbino structure.

FIG. 3 is a schematic sectional view showing a conventional MR element having a hole bar structure.

[Explanation of symbols]

 Reference Signs List 10 MR element 12 First electrode layer 14 First semiconductor layer 14a, 14b Both side surfaces of first semiconductor layer 16 Second electrode layer 16a, 16b Both side surfaces of second electrode layer 18 Second semiconductor layer 18a , 18b Both side surfaces of the second semiconductor layer 20 Third electrode layer

Claims (4)

(57) [Claims] 1. A magnetoresistive element having a structure in which a semiconductor is sandwiched between electrodes, wherein the first electrode layer, the first semiconductor layer, the second electrode layer, the second semiconductor layer, and the third electrode layer are Sequentially stacked, the
The first and second semiconductor layers are not in contact with each other, and the third electrode layer is in electrical contact with the first electrode layer without being in electrical contact with the second electrode layer. And a third electrode layer electrically contacting both side surfaces of the first and second semiconductor layers existing in a direction perpendicular to the lamination direction. 2. The method according to claim 1, wherein the first and second semiconductor layers are HgCd.
2. The composition according to claim 1, which is Te, HgMnTe or a mixed crystal thereof.
The magnetoresistive effect element as described in the above. 3. The method for manufacturing a magnetoresistive element according to claim 1, wherein the first electrode layer, the first semiconductor layer, the second electrode layer, and the second semiconductor layer are formed on a substrate. Sequentially formed, subsequently, the first semiconductor layer, the second electrode layer, the second semiconductor layer is etched so as to remain in a stripe shape, and then the second semiconductor layer is present in a direction perpendicular to the lamination direction A method of manufacturing a magnetoresistive element in which both side surfaces of an electrode layer are etched and then the third electrode layer is formed. 4. The method according to claim 3, wherein the first and second electrode layers are made of highly doped CdTe or HgTe, the first and second semiconductor layers are made of HgCdTe, and the third electrode layer is made of metal. The method for manufacturing a magnetoresistive element of the present invention.