JPH07169686A - Manufacture of semiconductor thin film and semiconductor thin film magnetoresistance element - Google Patents

Abstract

PURPOSE:To form good crystal whose each crystal grain is connected mutually directly on a substrate by forming a semiconductor thin film to a preliminary deposit layer on a foundation layer consisting of In on an Si single crystalline substrate wherein a surface oxide film is removed and hydrogen is absorbed. CONSTITUTION:A foundation layer 2 consisting of In is formed on an Si single crystalline substrate 1 wherein a surface oxide film is removed and hydrogen is adsorbed. A preliminary deposit layer 3 consisting of InSb is formed on the foundation layer 2 in a temperature range of 200 to 350 deg.C. A coating layer 11 consisting Sb is formed on the preliminary deposit layer 3. After it is exposed in air in such a state, it is heated to 350 deg.C or higher and the coating layer 11 is removed, and a semiconductor thin film layer 4 consisting of InSb is formed on the preliminary deposit layer 3 at 370 to 460 deg.C. Thereby, crystal of good crystallinity epitaxially grown on the single crystalline substrate 1 can be obtained while realizing reduction of manufacturing tact.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a semiconductor thin film used for a magnetoelectric conversion element used for detecting rotation and displacement, and a semiconductor thin film magnetoresistive element.

[0002]

2. Description of the Related Art Generally, various systems such as an optical system and a magnetic system are known as a rotation sensor. Among them, when they are used for applications such as dirt and dust which are affected by the atmosphere, The magnetic method that is less susceptible to is most advantageous. 2. Description of the Related Art In recent years, as various sensor elements have been mounted as automobiles have become electronic, a Hall sensor (Hall IC), a ferromagnetic thin film magnetoresistive element, which can be miniaturized as a rotation sensor, particularly a gear sensor combined with a rotating magnetic body, A rotation sensor using a semiconductor magnetoresistive element or the like has been studied, but the Hall element, Hall IC, and ferromagnetic thin film magnetoresistive element all have a small detection output, and it is necessary to reduce the gap between the object and the object to be detected. Therefore, there is a problem that it is difficult to use as a gear sensor.

On the other hand, the semiconductor magnetoresistive element is considered to be most suitable for the gear sensor because the detection output increases in proportion to the electron mobility of the semiconductor material and the tolerance of the gap with the object to be detected is large. . However, the operating temperature range of the semiconductor magnetoresistive element using bulk single crystal indium antimonide (hereinafter referred to as InSb), which has the highest electron mobility at present, is about -20 to + 80 ° C, and is used in the above-mentioned automobile. It does not satisfy the temperature range of -50 to + 150 ° C.

That is, in this InSb bulk single crystal, the electron mobility is
In the high temperature region, it is dominated by the scattering by polar optical phonons, and the maximum of the electron mobility is taken at the boundary of the regions in which they exist. From this maximum value, the electron mobility changes along the -1.7th power of the temperature on the high temperature side. Further, it has a steep peak on the extremely low temperature side (around 70K). in this way,
Although the electron mobility is high, the change with temperature is large, so that the operating temperature range is limited.

On the other hand, in the thin film type InSb magnetoresistive element, in addition to the scattering factors similar to those of the bulk single crystal, the scattering controlling factors such as grain boundary scattering and scattering due to dislocation defects are added, so that the absolute value of the electron mobility is obtained. However, the peak shifts to the high temperature side and has a relatively broad peak near room temperature, so the temperature characteristics are good. Therefore, -50
For use in a temperature range of up to + 150 ° C., the thin film type is preferable in terms of temperature characteristics. In addition to this, the thin-film InSb magnetoresistive element can easily be made high in resistance, the driving voltage of the element can be increased (the output is proportional to the driving voltage), and the power consumption and the size can be reduced. There are also advantages.

[0006]

As described above, although the thin-film type InSb magnetoresistive element has the advantage, it has not come into widespread use in high temperature applications. The causes are as follows. That is, in order to obtain an InSb thin film having good crystallinity and a sufficiently large electron mobility, a single crystal substrate (for example, CdTe, PbTe, etc.) having a close lattice constant is used as a substrate for growing the InSb thin film, and the InSb thin film is used. Epitaxial growth is sufficient, but the cost of these substrates is extremely high. Although it can be inexpensively produced by using an amorphous substrate such as glass, it is difficult to obtain a thin film having high electron mobility because the thin film formed is polycrystalline and the crystal grain size is as small as the film thickness. It was

In response to this, Toyo Communication Equipment Technical Report No. Four
0 (1987), as described by Fukunaka et al., It has been clarified that the electron mobility equivalent to that of a single crystal can be obtained by using a cleaved mica substrate. However, this method
Since the adhesion strength of the Sb thin film to the mica substrate is weak, this I
It is necessary to transfer the nSb thin film onto another supporting substrate through an adhesive layer such as epoxy and use it.
There was a problem such as cracking in the InSb thin film due to the difference in the thermal expansion coefficient between the Sb thin films, and it was not reliable enough for practical use in the temperature range of -50 to + 150 ° C.

Therefore, the object of the present invention is to have the stability at high temperature and the high electron mobility in consideration of the problems of the conventional thin film type InSb magnetoresistive element, and in the high temperature application such as the gear sensor for automobiles. Another object of the present invention is to provide a method of manufacturing a semiconductor thin film having sufficient reliability and a semiconductor thin film magnetoresistive element.

[0009]

According to a first aspect of the present invention, there is provided a method for producing a semiconductor thin film, comprising a step of removing an oxide film on a surface of a silicon (hereinafter referred to as Si) single crystal substrate to adsorb hydrogen, and a Si single crystal substrate. A step of forming an underlayer made of indium (hereinafter referred to as In) on the top, and a preliminary deposition layer containing at least In and antimony (hereinafter referred to as Sb) on the underlayer at a temperature of 200 to 350 ° C. at least in the initial stage of formation. In a range, a step of forming a coating layer made of Sb on the pre-deposited layer, a step of exposing the coating layer to the atmosphere with the coating layer formed thereon, and a step of exposing the coating layer exposed to the atmosphere in vacuum to 35
It includes a step of removing by heating at 0 ° C. or higher, and a step of forming a semiconductor thin film layer containing at least In and Sb on the preliminary deposition layer exposed by removing the coating layer.

According to a second aspect of the present invention, there is provided a method of manufacturing a semiconductor thin film according to the first aspect, wherein the predeposition layer and the semiconductor thin film layer are phosphide I.
n, In arsenide, In bismuth in, and a mixed crystal of InSb with at least one of gallium Sb, and InS
It consists of one side of b. A semiconductor thin film magnetoresistive element according to a third aspect is a semiconductor thin film obtained by the method for producing a semiconductor thin film according to the first or second aspect, wherein a short-circuit electrode and a protective film are formed on the semiconductor thin film layer.

[0011]

According to the method of manufacturing a semiconductor thin film of claim 1, when an underlayer made of In is formed on a Si single crystal substrate from which an oxide film on the surface is removed and hydrogen is adsorbed, the underlayer is a preliminary deposition layer. A smooth layer is formed at the temperature for forming. Next, the pre-deposited layer formed on this underlayer becomes a large crystal body extending in the surface direction of the substrate and
The epitaxial growth film inherits the crystal orientation of the single crystal substrate. By forming a coating layer made of Sb on the preliminary deposition layer from this state, it becomes possible to prevent the preliminary deposition layer from being oxidized even when exposed to the atmosphere.
Since it is possible to separate the apparatus for forming the underlayer, which requires the control of the vapor deposition film thickness of n, and the apparatus for forming the semiconductor thin film, which is less necessary and can simultaneously process a large number of sheets, the manufacturing tact can be shortened. Can be planned. The coating layer made of Sb evaporates and is removed from the substrate surface together with its own oxide layer by raising the temperature to 350 ° C. or higher, so that the surface of the preliminary deposition layer before the formation of the coating layer appears. Next, by forming a semiconductor thin film on this preliminary deposition layer, the growth rate of crystal grains in the surface direction is increased, and high-quality crystals in which individual crystal grains are connected can be directly formed on the substrate. Since it has a high adhesive strength, it is possible to manufacture a semiconductor thin film having high temperature stability and high electron mobility.

According to the method of manufacturing a semiconductor thin film of claim 2, in the method of claim 1, the preliminary deposition layer and the semiconductor thin film layer are:
Since it is composed of a mixed crystal of at least one of In phosphide, In arsenide, In, bismuth indium, and gallium Sb and InSb, or one of InSb alone, the same effect as in claim 1 can be obtained. According to the semiconductor thin film magnetoresistive element of claim 3, since the short-circuit electrode and the protective film are formed in the semiconductor thin film layer of the semiconductor thin film obtained by the method of manufacturing a semiconductor thin film of claim 1 or 2, for example, for automobiles. It is possible to provide a reliable semiconductor thin film magnetoresistive element having excellent characteristics suitable for a gear sensor or the like.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A method of manufacturing a semiconductor thin film according to a first embodiment of the present invention will be described with reference to the drawings. Figure 1
It is the basic configuration of the method for manufacturing a semiconductor thin film of this embodiment.
The first step is a step of removing the oxide film on the surface of the Si single crystal substrate 1 to adsorb hydrogen as shown in FIG. As the Si single crystal substrate 1 of this example, one having a high specific resistance cut to the (111) plane was used. The Si single crystal substrate 1 is sequentially subjected to organic cleaning, acid cleaning and alkali cleaning, and then the Si single crystal substrate 1 is treated with a 1% hydrofluoric acid aqueous solution.
The surface oxide film of was removed and rinsed in ultrapure water.
At this time, hydrogen on the atoms is adsorbed on the surface of the Si single crystal substrate 1, and it is possible for the hydrogen to remain stable on the (111) plane in particular, and there is an effect of preventing surface oxidation.

In the second step, as shown in FIG.
In this step, the underlayer 2 made of In is formed on the i single crystal substrate 1. That is, after the first step, the Si single crystal substrate 1
Is immediately introduced into the vacuum vapor deposition apparatus, and the vacuum degree is 5 × 10 ⁻⁴ P
After the temperature is set to a or less, the substrate temperature is set to room temperature to 350 ° C,
Under vacuum degree of 1 × 10 ⁻³ Pa or less, as shown in FIG. 1B, the underlayer 2 made of In was formed by the vapor deposition method by resistance heating.

The third step is shown in FIG. 1C after the second step.
As shown in FIG. 3, a preliminary deposition layer 3 containing at least In and Sb is formed on the underlayer 1 at least 200 at the initial stage of formation.
It is a step of forming in a temperature range of up to 350 ° C. In this example, InSb was used for the preliminary deposition layer 3 and was formed to a thickness of about 5 to 100 nm by a binary vapor deposition method of In and Sb.

Here, when the temperature at the start of forming the underlayer 2 and the preliminary deposition layer 3 reaches 350 ° C. or higher, the I of the underlayer 2 is increased.
n has a sphere shape on the Si single crystal substrate 1, and even if the preliminary deposition layer 3 is formed on this, a film shape cannot be obtained. In addition, In may exist in a smooth layered state at lower temperatures, but when the temperature at the start of formation of the preliminary deposition layer 3 becomes 200 ° C. or lower, Si
Although the (111) orientation is aligned with the plane orientation of the single crystal substrate 1, the in-plane directions are not aligned and an epitaxial growth film cannot be obtained. Therefore, it is necessary to form InSb of the preliminary deposition layer 3 in the temperature range of 200 to 350 ° C. at the initial stage of formation. The thickness of In of the underlayer 2 is I
A thickness of 0.1 nm or more, which is equivalent to a monoatomic layer in (111) of nSb, is required. However, when In becomes too thick, the in-plane orientation of the preliminary deposition layer 3 formed on this layer becomes uniform. Since it disappears, it is necessary to set the thickness to 2 nm or less.

The fourth step is, as shown in FIG.
This is a step of forming the coating layer 11 made of Sb on the preliminary deposition layer 3. In the embodiment, the substrate temperature is set to 300 ° C. or lower and S
The coating layer 11 made of b is formed. The surface of the coating layer 11 is shown in FIG.
As shown in (e), the surface is oxidized and the natural oxide film 12 is formed. At this time, when the oxidation progresses to the preliminary deposition layer 3, the semiconductor thin film 4 to be formed thereafter does not grow epitaxially. Therefore, the thickness of the coating layer 11 needs to be 10 nm or more to prevent this.

The fifth step is a step of exposing the coating layer 11 to the atmosphere with the coating layer 11 formed. That is, after the coating layer 11 is formed in the fourth step, the coating layer 11 is transported in the atmosphere or stored in dry nitrogen, and then again introduced into the vacuum vapor deposition apparatus. Here, the vacuum vapor deposition apparatus at this time may be the same as or different from the apparatus for forming the base layer 2 and the preliminary deposition layer 3, but since the formation of the base layer 2 requires fine control of the film thickness, An apparatus for leaf treatment is suitable, and an apparatus capable of treating a large amount at the same time is more suitable because it is not necessary for forming the semiconductor layer 4 to be formed next. Therefore, it is possible to shorten the manufacturing tact by using another vacuum vapor deposition apparatus.

The sixth step is the coating layer 11 exposed to the atmosphere.
Is a step of removing by heating to 350 ° C. or higher in vacuum. That is, the substrate temperature is raised in order to remove the coating layer 11 and the natural oxide film 12. S of coating layer 11
Since the natural oxide film 12 made of b or its oxide has a high equilibrium vapor pressure, it is vaporized and easily removed by setting the substrate temperature to 350 ° C. or higher. As a result, the surface of the substrate becomes the surface of the preliminary deposition layer 3 before forming the coating layer 11.

The seventh step is a step of forming a semiconductor thin film layer 4 containing at least In and Sb on the pre-deposition layer 3 exposed by removing the coating layer 11 as shown in FIG. 1 (f). That is, the semiconductor thin film layer 4 was formed by forming InSb in the temperature range of 370 to 460 ° C. by using the binary vapor deposition method of In and Sb similarly to the preliminary deposition layer 3. Within this temperature range, the Sb / In supply ratio should be 2
If the above conditions are maintained, InSb having a stoichiometric composition can be easily obtained, the growth rate of crystal grains in the plane direction is high, and a good-quality semiconductor thin film 4 in which individual crystal grains are connected can be obtained. If the formation temperature is lower than 370 ° C., the Sb / In supply ratio for obtaining the stoichiometric composition is limited to an extremely narrow range, and the growth rate of the crystal grains in the plane direction is small. It is difficult to obtain a good quality InSb thin film with good reproducibility. If the temperature is higher than 460 ° C, In
Since the desorption of Sb from Sb becomes severe and the crystallinity decreases, a good quality InSb thin film cannot be obtained. Therefore, the formation temperature of the semiconductor thin film 4 needs to be in the range of 370 to 460 ° C.

FIG. 2 shows the evaluation results of the crystallinity of the semiconductor thin film layer 4 made of InSb thus obtained by X-ray diffraction. From the figure, it is understood that the semiconductor thin film 4 is epitaxially grown on the (111) plane and has good crystallinity. The electron mobility of the semiconductor thin film layer 4 is 3 μm as measured by the van der Pauw method.
It was 4 to 6 m ² / V · s (room temperature value), and a semiconductor thin film layer 4 made of good quality InSb having an electron mobility similar to a single crystal could be obtained. Further, the adhesion between each of the Si single crystal substrate 1, the underlayer 2, the preliminary deposition layer 3, and the semiconductor thin film 4 is good, and −50.
Even if the temperature cycle between ˜ + 150 ° C. was repeated, problems such as peeling and characteristic deterioration did not occur.

According to this embodiment, the underlayer 2 made of In is formed on the Si single crystal substrate 1 from which the surface oxide film has been removed and hydrogen has been adsorbed, and the preliminary deposition of InSb is made on this underlayer 2. The layer 3 is formed in a temperature range of 200 to 350 ° C., the coating layer 11 made of Sb is formed on the preliminary deposition layer 3, exposed to the atmosphere in this state, and then 350 in a vacuum.
The coating layer 11 is removed by heating at a temperature of not less than 0 ° C., and the semiconductor thin film layer 4 made of InSb is formed on the preliminary deposition layer 3 in the range of 370 to 370.
By forming at 460 ° C., it is possible to obtain a product having good crystallinity which is epitaxially grown on the Si single crystal substrate 1 while shortening the manufacturing tact, and has stability at high temperature and high electron mobility. A semiconductor thin film can be provided.

A semiconductor thin film magnetoresistive element according to an embodiment of the present invention will be described with reference to FIG. That is, in this semiconductor thin film magnetoresistive element, the semiconductor thin film layer 4 obtained by the above-described method is processed by the photolithography method, the short-circuit electrode 5 made of copper or the like is formed, and the protective film 6 made of silicon dioxide or the like is further formed. Is formed.

The semiconductor thin film magnetoresistive element thus obtained has extremely high reliability without causing element deterioration such as peeling, cracking and characteristic deterioration even after repeated temperature cycle test and humidity resistance test at -50 to + 150 ° C. It was confirmed to have. According to this embodiment, the characteristics of the semiconductor thin film magnetoresistive element are not deteriorated due to film cracks and the like, which are conventionally generated, have sufficient reliability even in the temperature range of -50 to + 150 ° C, and have excellent characteristics. Can be provided.

Although the Si single crystal substrate 1 having the (111) plane orientation is used in the above-mentioned embodiment, (10
0 to 1 from (0) and (110) planes and their plane orientations
It is also possible to use the Si single crystal substrate 1 having a plane orientation inclined in the range of 0 degree. Further, as the method for removing the surface oxide film of the Si single crystal substrate 1, a hydrofluoric acid aqueous solution was used. However, an ammonium fluoride aqueous solution, hydrogen plasma in a vacuum deposition apparatus, hydrogen ion beam irradiation or heating in hydrogen is used. Etc. may be used.

Although InSb is used as the semiconductor thin film 4, a semiconductor made of a mixed crystal of InSb and any one or more of InP phosphide, In arsenide, In, bismuth indium, and gallium Sb may be used. It is possible to obtain an epitaxially grown material having good crystallinity, high electron mobility, and good adhesion between layers. Further, although the underlayer 2 made of In, the preliminary deposition layer 3 made of InSb, and the semiconductor thin film layer 4 were all formed by the vacuum evaporation method, the PAD method (plasma assisted deposition method), the ICB method (ion cluster beam) Method, etc., the film forming temperature can be further lowered by using a film forming method using appropriate energy of plasma, ions, etc.
A semiconductor thin film having good characteristics can be obtained.

[0027]

According to the method of manufacturing a semiconductor thin film of the first aspect, when an underlayer made of In is formed on a Si single crystal substrate from which an oxide film on the surface is removed and hydrogen is adsorbed, the underlayer is preliminarily prepared. A smooth layer is formed at the temperature at which the deposited layer is formed. Next, the preliminary deposition layer formed on the underlayer becomes a large crystal body extending in the surface direction of the substrate and an epitaxial growth film that inherits the crystal orientation of the Si single crystal substrate. By forming a coating layer made of Sb on the preliminary deposition layer from this state, it is possible to prevent the preliminary deposition layer from being oxidized even when exposed to the atmosphere, and it is necessary to control the deposition thickness of In. Since the formation device for the formation and the formation device for the semiconductor thin film, which is less necessary and capable of simultaneously processing a large number of sheets, can be separated, the manufacturing tact can be shortened. The coating layer made of Sb evaporates and is removed from the substrate surface together with its own oxide layer by raising the temperature to 350 ° C. or higher, so that the surface of the preliminary deposition layer before the formation of the coating layer appears. Next, by forming a semiconductor thin film on this preliminary deposition layer, the growth rate of crystal grains in the surface direction is increased, and high-quality crystals in which individual crystal grains are connected can be directly formed on the substrate. Since it has a high adhesion strength, it has the effect that a semiconductor thin film having high temperature stability and high electron mobility can be manufactured.

According to the method of manufacturing a semiconductor thin film of claim 2, in the method of claim 1, the preliminary deposition layer and the semiconductor thin film layer are:
Since it is composed of a mixed crystal of at least one of In phosphide, In arsenide, In, bismuth indium, and gallium Sb and InSb, or one of InSb alone, the same effect as claim 1 can be obtained. According to the semiconductor thin film magnetoresistive element of claim 3, since the short-circuit electrode and the protective film are formed in the semiconductor thin film layer of the semiconductor thin film obtained by the method of manufacturing a semiconductor thin film of claim 1 or 2, for example, for automobiles. It is possible to provide a reliable semiconductor thin film magnetoresistive element having excellent characteristics suitable for a gear sensor or the like.

[Brief description of drawings]

FIG. 1 is a sectional view of a semiconductor thin film for explaining a method of manufacturing a semiconductor thin film according to an embodiment of the present invention.

FIG. 2 is an X-ray diffraction pattern of the manufactured semiconductor thin film.

FIG. 3 is a perspective view of a semiconductor thin film magnetoresistive element of the present invention.

[Explanation of symbols]

 1 Silicon Single Crystal Substrate 2 Underlayer 3 Preliminary Deposited Layer 4 Semiconductor Thin Film Layer 5 Short-Circuit Electrode 6 Protective Film 11 Covering Layer 12 Natural Oxide Film

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Makoto Kitahata 1006 Kadoma, Kadoma City, Osaka Prefecture Matsushita Electric Industrial Co., Ltd.

Claims (3)

[Claims] 1. A step of removing an oxide film on a surface of a silicon single crystal substrate to adsorb hydrogen, a step of forming an underlayer made of indium on the silicon single crystal substrate, and at least indium on the underlayer. 200 to 35 at least in the initial stage of formation of a pre-deposition layer containing
Forming in a temperature range of 0 ° C., forming a coating layer made of antimony on the preliminary deposition layer, exposing the coating layer to the atmosphere with the coating layer formed,
Removing the coating layer exposed to the atmosphere by heating it to 350 ° C. or higher in a vacuum; and forming a semiconductor thin film layer containing at least indium and antimony on the preliminary deposition layer exposed by the removal of the coating layer. And a method of manufacturing a semiconductor thin film. 2. The pre-deposited layer and the semiconductor thin film layer are one of a mixed crystal of at least one of indium phosphide, indium arsenide, indium bismuthide, and gallium antimonide and indium antimonide, or a simple substance of indium antimonide. The method for producing a semiconductor thin film according to claim 1, comprising: 3. A semiconductor thin film magnetoresistive element in which a short-circuit electrode and a protective film are formed on the semiconductor thin film layer of the semiconductor thin film obtained by the method for producing a semiconductor thin film according to claim 1.