JPH09214019A - Magnetoelectric transducer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an indium-antimony-arsenic magnetoelectric transducer which is high in sensitivity and excellent in heat resistance. SOLUTION: The magnetoelectric transducer comprises, as its magnetism sensitive part, a laminate which is made up of a silicon single crystal substrate 1, a crystalline rare earth oxide layer 2 of 3,000-30,000Å thick formed on the silicon single crystal substrate 1, and a semiconductor thin film 3 of stoichiometric indium/antimony/arsenic compound having a thickness of 0.5-2μm and expressed by a formula of InSb1-x Asx (where X being 0-1) formed on the layer 2.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention has high mobility.
Indium antimony arsenic (hereinafter referred to as InSb _1-XA
s_XAbbreviated) Magnetoelectric conversion using compound semiconductor thin film as magnetic sensing part
An element that is highly sensitive and has improved heat resistance.
The present invention relates to an electric conversion element.

[0002]

2. Description of the Related Art Magnetoelectric conversion elements such as Hall elements and semiconductor magnetoresistive elements are VTRs, floppy disks and CDs.
It is widely used as a rotational position detection sensor for a drive motor such as a ROM or a magnetic sensor for bill recognition. An indium antimony arsenide-based compound semiconductor thin film having high mobility is most suitable as the magnetic sensing part of such an element. Here, indium antimony arsenic is
It is a compound semiconductor represented by the general formula InSb _1-X As _X (X is 0 to 1).

In order for the magnetoelectric conversion element using these compound semiconductors as the magnetic sensing portion to function as a sensor, it is necessary to secure a practical resistance value, and the thickness is 0.5 to 1.5 μm.
It is an essential requirement to thin the film to a certain degree. In addition, high mobility is also required to ensure high sensitivity. One method that meets this demand is a method of forming a single crystal of a compound semiconductor, cutting it out, and polishing it to form a thin film. However, although this method can secure a mobility almost equal to that of a single crystal, it is difficult to uniformly form a thin film having the above thickness. Further, this method has a problem that the cost is very high.

Therefore, various methods for directly forming a thin film by vapor deposition have been studied. In this case, in order to obtain high mobility close to that of a single crystal, it is necessary to grow the crystal of the thin film when forming the thin film, and for that purpose it is essential to use a crystalline and insulating substrate. Is. Examples of such a substrate include insulating GaAs and sapphire. However, since these substrates are expensive, they cannot meet the demand of the era of cost reduction of elements.

Further, for example, Japanese Patent Publication No. 51-45234 discloses a so-called transfer method. That is, after forming a compound semiconductor thin film on a crystalline substrate such as mica by vapor deposition, etc., this thin film is adhered to another substrate using an adhesive such as epoxy resin, and then the substrate such as mica is removed. Is. In that case, since the resin layer is in direct contact with the semiconductor thin film, it is not suitable for heat resistant applications.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a magnetoelectric conversion element having high sensitivity and excellent heat resistance.

[0007]

Means for Solving the Problems The present inventors have found that an insulating and inexpensive substrate capable of forming a thin film having high mobility by direct vapor deposition or the like is formed by first forming a rare earth oxide layer on silicon. They have found that they can be obtained and have completed the present invention. That is, the present invention is a silicon single crystal substrate,
The crystalline and thickness formed on the silicon substrate is 3,
000 to 30,000 Å rare earth oxide layer, and the general formula InSb _1-X As _X (where X is 0
To 1) and a stoichiometric composition and a thickness of 0.5 to 2 μm of an indium antimony arsenide-based compound semiconductor thin film, which is used as a magnetic sensing element. Is.

Further, according to the present invention, a ferromagnetic material is adhered to a silicon substrate having the compound semiconductor layer and the rare earth oxide layer via a resin layer, and a magnetic chip for magnetic focusing is provided on the magnetic sensing portion of the compound semiconductor thin film. Is a structure in which the element is attached via a resin layer, and the magnetoelectric conversion element is characterized in that. FIG. 1 shows one embodiment of the present invention. A rare earth oxide layer 2 is formed on the single crystal silicon substrate 1, and InS is formed on the rare earth oxide layer 2.
The b _1-X As _X layer 3 is formed. FIG. 2 shows another embodiment of the present invention. That is, the structure shown in FIG. 1 is sandwiched between the ferromagnetic material 7 having the resin layer 6 interposed therebetween and the magnetic focusing magnetic material chip 5 having the resin layer 4 interposed therebetween. Due to the magnetic focusing effect, the embodiment of FIG. 2 can be several times more sensitive than the embodiment of FIG.

The structure according to the present invention can be formed mainly by vapor deposition means. First, a single crystal silicon substrate is prepared, and a rare earth oxide layer is formed on it by simple vapor deposition, electron beam vapor deposition, and sputtering. At this time, the rare earth oxide may be used as it is as a sample, or the rare earth metal described in Japanese Patent Publication No. 1-32601 filed by the inventors of the present invention may be deposited as a sample under a specific vapor deposition condition. Two or more kinds of oxides may be used,
It may be laminated. The thickness of these layers is 3,0
It is preferably from 00 to 30,000Å. If it is too thin, practical mobility does not appear, and if it is too thick, a compound semiconductor thin film having a good appearance cannot be obtained thereon.

The InSb _1-X As _X layer serving as the magnetically sensitive portion has a thickness of 0.5 to 2 μm in order to secure a practical resistance value.
It is preferable to set the degree. The present inventors have proposed various methods for increasing the mobility of this system by the following applications,
The semiconductor thin films produced by the methods described in these applications can be preferably applied to the present invention (Japanese Patent Publication No. 1-13211, Japanese Patent Publication No. 1-15135, Japanese Patent Publication No. 2-4784).
Japanese Patent Publication No. 9, Japanese Patent Publication No. 2-47850, Japanese Patent Publication No. 3-5
9571). Semiconductor thin film is simple vapor deposition, MB
It can be formed by means such as E.

Magnetic materials such as permalloy, ferrosilicon, and ferrite can be used as the material of the ferromagnetic material and the magnetic focusing chip. As the resin layer 6 used as an adhesive, a resin of epoxy or polyimide, or
Glass or the like can be used. Various resins are used as the resin layer 4 used as the chip adhesive, but a soft silicone resin can be preferably used.

InSb _1-X formed as described above
The substrate carrying the As _X thin film is subjected to a patterning process to form a magnetically sensitive portion, electrodes, and individual elements. Al, Ni, Cr, Cu, Pd, Au, etc. are used as the electrode metal,
Generally, the electrode preferably has a laminated structure of these metals. Further, the pellets are individually made by a dicing process, these pellets are fixed to a lead frame by a die bonder or the like, the electrodes of the pellet and the lead frame are connected by a wire bonder or the like, and a magnetoelectric conversion element is made by a molding process or the like.

[0013]

Now, the present invention will be described in further detail with reference to Examples.

[0014]

Example 1 A surface of a cerium mass was cleaned in an argon stream, and then placed on a tungsten boat of a vapor deposition machine, and single crystal silicon was placed at a predetermined position. First, inside the vapor deposition machine 1
A vacuum of 0 ^-7 Torr is applied, and then oxygen is introduced to bring the pressure to 10
A vacuum of ^-3 Torr was applied. After repeating this operation three times, a vacuum state of 5 × 10 ⁻⁵ Torr was established and cerium was vapor-deposited. The thickness was 5,000Å.

InSb was formed on the silicon substrate on which the cerium oxide layer was formed as follows. First In and S
A complex crystal thin film containing excess In was formed by b. The degree of vacuum is set to 7 × 10 ⁻⁶ Torr, the substrate temperature is set to 420 ° C., the total deposition time is set to 17 minutes, and the final temperature is set to 51 ° C.
The temperature was 5 ° C. During this period, the substrate temperature rising rate was 0 ° C./min for 0 to 6 minutes, 6 to 14 minutes, and 14 to 17 minutes after the start of vapor deposition, respectively.
It was set to 12.5 ° C / min and 0 ° C / min. The power applied to the In and Sb boats was kept constant for 15 minutes from the start, and then the power applied to the Sb boat was set to zero. The flying amounts of In and Sb were set to 2.6 g and 3.5 g.
It was confirmed visually that the crystal growth became excessive and the crystal growth proceeded.

Subsequently, the power of the In boat is set to zero, and the power of the third boat on which Sb is placed is applied, and
The substrate temperature was raised to 25 ° C. and Sb was vapor-deposited in 3 minutes. The mobility of the thus obtained InSb thin film was measured by the Van der Pau method to be 45,000 cm ² / V.
/ Sec. A semiconductor magnetoresistive element was produced using this wafer. A photolithography technique was used to form the device pattern.

3 to 5 show the structure of the semiconductor magnetoresistive element after patterning. 3 is a plan view thereof, FIG. 4 is a sectional view taken along line AA of FIG. 3, and FIG. 5 is a sectional view taken along line BB of FIG. A conductor layer 9 of ohmic contact Cu or the like is formed in a strip shape on a portion of the InSb thin film layer 3 other than the magnetic sensitive portion, and constitutes a portion called a raster electrode for short-circuiting an electric field. The width W of the raster electrode is 200 μm,
The interval L of InSb between the raster electrodes was 30 μm.

Further, an electrode layer 1 for connecting to an external circuit
0 was formed by soldering, and lead terminals made of phosphor bronze foil with a thickness of 0.03 mm were soldered. On top of that, 0.15m
A m-thick protective glass was attached with a silicone resin, and a semiconductor magnetoresistive element for a potentiometer was produced in which two semiconductor magnetoresistive elements were arranged so as to form a bridge circuit.

100 pieces were taken out from these elements and the characteristics were examined. As a result, the magnetic resistance change rate at a magnetic flux density of 0.4 T was 3.4 times on average, and no deterioration was observed in the temperature cycle test.

[0020]

Example 2 The back surface of the laminated body composed of the silicon single crystal, the cerium oxide layer and the InSb thin film layer obtained in Example 1 was polished and thinned, and laminated with ferrite and a polyimide resin. A photolithography method was used to form a Hall element pattern from this wafer. 6 is a plan view thereof, and FIG. 7 is a sectional view taken along the line CC. InS
b In the central portion of the thin film layer 3 other than the magnetic sensitive portion 3a, a conductor layer 11 of ohmic contact such as Cu is formed, and on top of that, a Ni layer 12 and an Au layer serving as an electrode layer for bonding. Layers 13 are stacked. The size of the pellet was 0.8 mm square.

In each magnetic sensing part of this wafer, Japanese Patent Publication No. 7-13
A magnetic focusing magnetic chip was mounted by the method described in Japanese Patent Publication No. 987. Next, dicing was performed to divide into individual elements, these pellets were die-bonded to the island portion on the lead frame, and the leads and the electrode portions of the pellets were connected by Au wires by wire bonding for electrical connection. Further, a Hall element was created through steps such as transfer molding and electrical inspection.

The average sensitivity of these devices at 1 V and 500 G reached 330 mV. An immersion test was conducted in a solder bath at 300 ° C., but no characteristic change of 5% or more was shown.

[0023]

According to the present invention, it is possible to obtain a magnetoelectric conversion element having high sensitivity and excellent heat resistance.

[Brief description of drawings]

FIG. 1 is a structural diagram of an example of a magnetoelectric conversion element of the present invention.

FIG. 2 is a structural diagram of another example of the magnetoelectric conversion element of the present invention.

FIG. 3 is a plan view of a semiconductor magnetoresistive element according to Example 1 of the present invention.

FIG. 4 is a sectional view taken along line AA of FIG. 3;

FIG. 5 is a sectional view taken along line BB of FIG. 3;

FIG. 6 is a plan view of a Hall element according to Example 2 of the present invention.

FIG. 7 is a sectional view taken along line CC of FIG. 6;

[Explanation of symbols]

1 Silicon Single Crystal Substrate 2 Rare Earth Oxide Layer 3 InSb _1-X As _X Layer 4 Resin Layer 5 Magnetic Focusing Magnetic Chip 6 Resin Layer 7 Ferromagnetic Material 9 Raster Electrode Layer 10 Lead Terminal Soldering Electrode Layer 11 Conductive Layer 13 Bonding electrode layer

Claims (2)

[Claims] 1. A silicon single crystal substrate, and a crystalline and formed layer having a thickness of 3,000 to 30, formed on the silicon substrate.
A rare earth oxide layer of 000 Å and a stoichiometric composition represented by the general formula InSb _1-X As _X (where X is 0 to 1) and a thickness of 0.5 to A magnetoelectric conversion element comprising a laminated body of a 2 μm indium antimony arsenide-based compound semiconductor thin film as a magnetic sensing part. 2. A structure in which a ferromagnetic material is attached to a silicon substrate via a resin layer, and a magnetic focusing magnetic chip is attached to the magnetic sensing portion of the compound semiconductor thin film via the resin layer. The magnetoelectric conversion element according to claim 1.