JP2001326400A - METHOD FOR MANUFACTURING InSb THIN-FILM BOARD - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing a reliable InSb thin-film board which is sensitive and applied to a magnetoelectric transducer. SOLUTION: Related to a board 1A, an Sa film 3 is laminated and formed on a first layer while an In film 4 formed on a second layer by a specified thickness, forming an InSb compound semiconductor crystal film 5 of stoichiometry composition. An InSb film 6 is formed thereon whose In exceeds a stoichiometry composition by 0.5-2.5 at.%. Then its surface is treated in an acidic solution to remove the excessive In, providing an InSb thin-film board 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a compound semiconductor polycrystalline film having high sensitivity, high reliability and high product sensitivity (.mu.H.Rs) applicable to magnetoelectric transducers (for example, Hall elements and MR elements). For example, the present invention relates to a method for manufacturing an indium antimony (InSb) thin film substrate.

[0002]

2. Description of the Related Art Conventionally, as an inexpensive and highly sensitive material for a magnetoelectric conversion element (for example, a Hall element or an MR element), InS having a stoichiometric composition and a high Hall mobility has been used.
A b-type polycrystalline film is often used.

A hole motor used for a CD-ROM, a DVD, or the like detects rotation using a hall element and a magnet.
The size of magnets used for detecting the rotation of a hall motor has also been reduced in size. As the size of the magnet decreases, the magnetic flux density decreases. Therefore, the sensitivity of the Hall element for detecting the magnetic flux density is required to be higher and higher.

The material of the Hall element is InS
Although there are compounds such as b, InAs, and GaAs, generally, InSb, which has a low material cost and has a high hole mobility, is widely used because of its high sensitivity. In order to increase the hole mobility of InSb, it is necessary to improve the crystallinity. Practically, In
The hole mobility of the Sb film is 20,000 cm ² / V · se
c or more is required.

As this InSb Hall element, for example, Japanese Patent Application Laid-Open Nos. 9-148652 and 9-14
There is one disclosed in JP-A-8653. That is, Japanese Patent Application Laid-Open No. Hei 9-148652 discloses that an excess of In and S
After forming a layer consisting of b, and further evaporating Sb in excess of the In, an InSb film is formed, and a ferrite is placed on the InSb film via a polyimide resin. By peeling, the InSb film is transferred onto the ferrite, a hole pattern is formed on the InSb film by a photolithography method, and diced to a desired size to obtain an InSb Hall element. .

[0006] Japanese Patent Application Laid-Open No. 9-148655 discloses
A glass is formed on a ferrite substrate, In and Sb are vapor-deposited on the glass by a vacuum vapor deposition method, Sb is further vapor-deposited to form an InSb film, and a hole pattern is formed on the InSb film by a photolithography method. It is formed and diced to a desired size to obtain an InSb Hall element.

However, in the former case, when an InSb film is formed on a substrate made of mica, a high hole mobility can be obtained. Therefore, a Hall element made from this InSb film has high sensitivity. When peeling the substrate,
The InSb film cannot be completely removed from the entire substrate,
Because it takes a lot of time to completely peel off,
Manufacturing work was difficult and the yield was poor. Therefore, In
There was a disadvantage that the manufacturing cost of the Sb film was increased.

In the latter case, since the InSb film is formed directly on the glass formed on the ferrite substrate, if there is a mismatch in the lattice between the InSb film and the glass, the InSb film becomes non-oriented. Therefore, there is a problem that the hole mobility is low and the sensitivity does not increase.

[0009]

As described above, in the conventional method for forming a thin film substrate for a magnetoelectric conversion element such as a Hall element, a thin film substrate having a high hole mobility μH is formed by a simple method. Therefore, it has been difficult to form a thin film substrate for a Hall element having, for example, a high product sensitivity (μH · Rs). Further, in the compound semiconductor InSb crystal film formed on the substrate, the crystal growth state of the film is determined by physical and chemical changes of the substrate surface such as the substrate temperature and vapor deposition particles.

Here, the hole mobility of the InSb film is μ
Assuming that H is the sheet resistance and Rs is the sheet resistance, as described above, the sensitivity of the ordinary low-voltage input Hall element is proportional to the product sensitivity (μH · Rs). Therefore, in order to increase the sensitivity of the element, it is more preferable to improve the hole mobility μH as described above, and it is more preferable to improve the sheet resistance Rs. However, the sheet resistance Rs is determined by the relationship between the specific resistance ρ, which is a physical quantity of the thin film substrate, and the thickness t of the thin film substrate, that is, Rs = ρ / t, and cannot be improved unless the thickness of the thin film substrate for the element is determined. There's a problem.

Accordingly, the present invention has been made to solve the above-mentioned problems, and has been made in order to obtain an InSb thin film substrate having a high hole mobility by a simple method.
b. To provide a method for manufacturing a thin film substrate.

[0012]

In order to solve the above-mentioned problems, as a first invention, Sb is formed on a first layer on a substrate 1A.
The InSb compound semiconductor crystal film 5 having a stoichiometric composition is formed by laminating the In film 4 with a predetermined thickness on the film 3 and the second layer, and then the stoichiometric composition is formed on the InSb compound semiconductor crystal film 5. An InSb-based film 6 with an excess of 0.5 at% or more and 2.5 at% or less is formed and then the surface is treated with an aqueous acid solution to remove the excess In.
The method of manufacturing the nSb thin film substrate 10 is described as a second invention.
On the substrate 1B, the first
An Sb film is formed as a layer, and an In film 4 is formed as a second layer with a predetermined thickness to form an InSb compound semiconductor crystal film 5 having a stoichiometric composition. An InSb-based film 6 having an In excess of 0.5 at% to 2.5 at% based on the stoichiometric composition, and then removing the excess In by treating the surface with an aqueous acid solution; The method for producing an InSb thin film substrate according to claim 1 or 2, wherein the acid is an aqueous solution containing at least one of sulfuric acid and hydrochloric acid. As the In
The insulating film 2 in contact with the Sb compound semiconductor crystal film 3 is made of silicon oxide, aluminum oxide, glass, aluminum nitride,
3. The method of manufacturing the InSb thin film substrate 10 according to claim 2, wherein the method is any one of films mainly composed of silicon nitride, tantalum nitride, and titanium nitride.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION

Embodiment 1 A method for manufacturing an InSb thin film substrate according to the present invention will be described below with reference to FIGS. Figure 1,
FIG. 2 is a side view of an InSb thin film substrate formed by the method of manufacturing an InSb thin film substrate according to the present invention, and FIG. 3 is a diagram showing In and Sb concentrations before acid treatment, normalized mobility after acid treatment, and after acid treatment. FIG. 4 is an explanatory view showing the relationship between the normalized sheet resistance of FIG.
FIG. 4 is an explanatory diagram showing an example of a method for evaluating a Hall element chip (cross pattern).

First, a method of forming the InSb thin film substrate 10 will be described with reference to FIGS. As a thin film substrate for film formation evaluation, an SiO ₂ film 2 as an insulating film having a thickness of 200 nm was formed on a SiO ₂ substrate 1A having a polished surface or a magnetic ferrite substrate 1B having a polished surface by plasma CVD.
Was used. For evaluation of the surface condition of the substrates 1A and 1B, a stylus type roughness meter, an optical microscope, and an electron microscope (SE
M).

As a substrate material, laminated In, Sb
Must be examined in relation to When the magnetic ferrite substrate 1B is used, when the InSb thin film substrate 10 is used as a device, there is no peeling or transfer process from mica, so that the InSb thin film has excellent sensitivity, unbalanced voltage performance, low cost and high reliability. An element is obtained.

For film formation, the following samples were prepared using a binary resistance heating vapor deposition machine. The thickness of the first layer Sb film 3 is 15 n
m and overlaid thereon so as to have a stoichiometric composition.
By laminating the film 4 and performing a heat treatment at 410 ° C., an InSb semiconductor crystal film 5 having a stoichiometric composition is formed.

Next, the InSb semiconductor crystal film 5 having this stoichiometric composition is used as a base film, and a stoichiometric composition near the stoichiometric composition is 0.5 at% to 2.5 at% in the vicinity of the stoichiometric composition. % Or less of the InSb-based film 6 in excess of In. This is because, even for an InSb-based film which is originally likely to have a stoichiometric composition, the film is formed at a substrate temperature higher than the re-evaporation temperature of Sb. This is because it is easy to control.

Thereafter, the InSb-based film 6 in excess of 0.5 at% to 2.5 at% based on the predetermined stoichiometric composition is treated with an aqueous acid solution to remove the excess In. Was formed so that the total thickness of the InSb film 5 was 1 μm. The aqueous acid solution is preferably an aqueous solution containing at least one of sulfuric acid and hydrochloric acid.

The insulating film 2 used on the magnetic ferrite substrate 1B whose surface is polished is made of silicon oxide (SiO 2).
₂ ), any one of films mainly composed of aluminum oxide (Al ₂ O ₃ ), glass, aluminum nitride (AlN), silicon nitride (SiN), tantalum nitride (TaN), and titanium nitride (TiN), It is preferably an amorphous film. In the case of an amorphous film, compared to a crystalline film,
This is because the result that the hole mobility is more than doubled.
The glass is preferably an alkali-free glass (Corning # 7059) substrate.

The above-mentioned excess amount of excess In is converted into XRD (Xray Diffraction Pattern) as In alone.
The measurement cannot be performed by the ern) method or the like. Therefore, it is considered that In-rich (rich) crystal grains are formed in the grain boundaries, mainly in particular crystal grains. The following can be inferred as the reason for this.

That is, as described above, originally InSb
Is likely to have a stoichiometric composition. On a phase diagram (phase diagram), when the In melting point is 155 ° C. or more and the InSb liquidus line (530 ° C.) or less, an excess In liquid phase and + InSb solid phase are separated and exist. Are known (for example, METALL
URGY AND METALLURGICAL ENGINEERING SERIES CONNST
ITUTION OF BINARY ALLOYS Dr.phil.Max Hansen M
cGRAW-HILL BOOK CO., INC).

Furthermore, the diffusion coefficients of In and Sb in InSb are much larger than those of other elements (III-V compound semiconductor crystal (binary) data book (Japan Electronics Association)). It can be inferred from these two factors that excess In exists in the grain boundaries and In-rich crystal grains.

InSb having a stoichiometric composition is soluble in nitric acid but not in hydrochloric acid or sulfuric acid. On the other hand, In metal and Sb metal alone dissolve in hydrochloric acid and sulfuric acid. In above
The rich crystal grains are also dissolved in hydrochloric acid and sulfuric acid, and by treating the InSb film having no holes in the film containing more In with an acid, the crystal grains of several μm are dissolved and holes can be seen. At a predetermined In-rich amount, as a result of the acid treatment, the hole mobility μH remains unchanged in a high state and the film sheet resistance R
s rises.

As a result, a high mobility (11
1) An InSb film having a stoichiometric composition having a high sheet resistance and a preferentially oriented InSb film can be easily formed. Therefore,
For example, a magnetic ferrite substrate 1B provided with an SiO ₂ insulating film
The InSb film is formed thereon, and a Hall element using the InSb film has higher product sensitivity (μH · Rs) and can realize an element with higher reliability.

To form a magnetoelectric conversion element, for example, a Hall element, an InSb film is patterned into a predetermined element shape (cross) to form an electrode. Furthermore, after laminating the magnetic flux collecting ferrite chips,
A Hall element chip is used (see FIG. 4).

The crystallinity was evaluated by the XRD method, and it was confirmed that all the InSb thin film substrates 5 were (111) preferentially oriented crystals. Various properties such as the hole mobility μH are measured by a well-known Van der Pauw method, and the composition analysis of the InSb thin film substrate 10 after the film formation and the acid treatment is performed by the EPM.
A was performed.

InSb thin film substrate 10 after film formation by EPMA
As a result of analyzing the composition of
%) / Sb (at%)}, the InS of the composition of the conventional film
b From thin film substrate (50/50) to (53.2 / 46.8)
Is the composition concentration range. In addition, only in the InSb thin film substrate having the composition (53.2 / 46.8), a slight In metal peak was observed, and a large decrease in the hole mobility μH was observed.

As an example of the acid treatment of the InSb thin film substrate 10, the substrate was immersed in concentrated hydrochloric acid at 40 ° C. for 2 minutes. 1 minute or more 3
Within the range of 0 minutes or less, the composition after the acid treatment was a stoichiometric composition (50/50) in all the films. Experiments were also conducted on an aqueous hydrochloric acid solution containing 60% sulfuric acid and aqueous hydrogen peroxide as the acid to be used for the acid treatment, and the results were measured.

FIG. 3 shows In and Sb concentrations (at
FIG. 4 is an explanatory diagram of the result of examining the relationship between%) and normalized mobility and normalized sheet resistance after acid treatment. Here, the normalized mobility μH (In) / μH (50) is the hole mobility μH (50) (denominator) of a conventional stoichiometric (50/50) film.
Mobility of In-rich film after acid treatment
(In). Similarly, the normalized sheet resistance Rs (In) / Rs (50) is the sheet resistance Rs (In) of the In-rich InSb film after the acid treatment with respect to the sheet resistance Rs (50) (denominator) of the conventional stoichiometric composition. It is expressed by the ratio of

As is apparent from FIG. 3, the normalized mobility is 2.5 atm from the conventional stoichiometric composition of In50.
It can be seen that after showing a constant value in the range of In52.5, which is a% rich composition, the value sharply decreases on the higher In concentration side. In this region, for example, the hole mobility μH required for a high-sensitivity Hall element is 23000 cm 2 / V
-It turns out that a high value more than sec can be realized.

Further, looking at the normalized sheet resistance in the same figure, it is clear that the sheet resistance after the acid treatment is large in the range of 0.5 at% rich (In 50.5) or more and 2.5 at% rich (In 52.5). 5-10%). Further, it can be seen that in the case of the In-rich composition, the sheet resistance considerably increases with a sharp decrease in the hole mobility μH.

The reason for this is that if the film exceeds the range of the In-rich composition of the present embodiment, many InS
Since a large number of holes in which the b crystal grains are considered to be dissolved are observed, it is inferred that the hole mobility μH decreases as the resistance increases. InSb exceeding 1.5 at%
In the film, the same holes as described above are observed although the amount is small after the acid treatment. Therefore, it is inferred that the dissolution and removal of the grain boundaries or the In-rich crystal grains cause an increase in the sheet resistance despite the constant hole mobility μH.

[0033]

Embodiment 2 CaF ₂ film, ZnO as a crystalline insulating film
Film and silicon oxide (Si) as an amorphous insulating film.
A magnetic ferrite substrate 1B provided with an O ₂ ) film, an aluminum oxide (Al ₂ O ₃ ) film, an aluminum nitride (AlN) film, a silicon nitride (SiN) film, a tantalum nitride (TaN) film, and a titanium nitride (TiN) film. The same evaluation as in Example 1 was performed.

The insulating base film 2 including silicon oxide (SiO ₂ ) was formed by RF magnetron sputtering, and the thickness of the film was made the same as 200 nm. The nitride was formed by a so-called reactive sputtering method in which N ₂ gas was introduced into Ar gas during sputtering. Similar results were obtained even when the insulating base film 2 had two or three layers.

The determination of the amorphous state was made by confirming that there was no peak by XRD. As a result, an InSb thin film substrate having a hole mobility of half or less of the crystalline CaF ₂ film and the ZnO film as compared with the amorphous film was obtained. In the case of an amorphous film, the same result as that shown in Example 1 was obtained.

On the magnetic ferrite substrate 1B provided with a silicon oxide (SiO ₂ ) insulating film, the above I
The nSb film was formed by performing an acid treatment after the formation of the film. As a result of forming a Hall element using this in the above-described process and evaluating the sensitivity, a highly reliable magnetoelectric conversion element corresponding to the product sensitivity (μH · Rs) and having a sensitivity 5% to 10% higher than the conventional element was obtained. I realized it.

[0037]

According to the first invention, an Sb film is formed as a first layer and an In film is formed as a second layer with a predetermined thickness on a substrate.
After forming a stoichiometric InSb compound semiconductor crystal film, an InSb-based film having an In excess of 0.5 at% or more and 2.5 at% or less than the stoichiometric composition is formed on the InSb compound semiconductor crystal film. Thereafter, the excess In was removed by treating the surface with an aqueous acid solution, so that the magnetoelectric conversion having high hole mobility and excellent high sensitivity characteristics was substantially formed on the substrate provided with the insulating film. An InSb thin film substrate applicable to a device can be obtained.

According to the second invention, the Sb film is formed on the first layer and the In film is formed on the second layer via the at least one insulating film on the substrate.
A film is laminated to a predetermined thickness, and a stoichiometric composition of InSb
After forming the compound semiconductor crystal film, an InSb-based film having an In excess of 0.5 at% or more and 2.5 at% or less than the stoichiometric composition is formed on the InSb compound semiconductor crystal film. Is treated with an aqueous acid solution to remove the excess In, whereby an InSb thin film substrate having high hole mobility and excellent in high sensitivity characteristics can be obtained.

According to the third aspect of the present invention, the acid is an aqueous solution containing at least one of sulfuric acid and hydrochloric acid. It is possible to obtain an InSb thin film substrate which can be applied to a magnetoelectric conversion device having high sensitivity and excellent sensitivity.

According to the fourth invention, the insulating film in contact with the InSb compound semiconductor crystal film is made of silicon oxide, aluminum oxide, glass, aluminum nitride, silicon nitride,
3. A method for producing an InSb thin film substrate according to claim 2, wherein the method is a film composed of any one of tantalum nitride and titanium nitride as a main component, thereby providing a magnetoelectric device having high hole mobility and excellent sensitivity characteristics. An applicable InSb thin film substrate can be obtained.

[Brief description of the drawings]

FIG. 1 is a side view of an embodiment of an InSb thin film substrate formed by a method of manufacturing an InSb thin film substrate according to the present invention.

FIG. 2 is a side view of another embodiment of the InSb thin film substrate formed by the method of manufacturing an InSb thin film substrate according to the present invention.

FIG. 3 is an explanatory diagram showing the relationship between the In and Sb concentrations before acid treatment, the normalized mobility after acid treatment, and the normalized sheet resistance after acid treatment.

FIG. 4 is an explanatory diagram showing an example of a method for evaluating a Hall element chip (cross pattern).

[Explanation of symbols]

 Reference Signs List 1A, 1B substrate 3 Sb film 4 In film 5 InSb film 6 InSb-based film 10 InSb thin film element

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 43/12 H01L 21/306 A F-term (Reference) 4K029 AA02 AA08 BA10 BA14 BA21 BB02 BD01 FA07 GA00 5F043 AA26 BB18 GG10 5F103 AA01 DD28 DD30 HH10 LL20 PP03 PP06 RR05

Claims (4)

[Claims] 1. An Sb film as a first layer and an In film as a second layer on a substrate.
A film having a predetermined thickness is formed by lamination, and a stoichiometric composition of InSb
After the compound semiconductor crystal film is formed, an InSb-based film having an In excess of 0.5 at% or more and 2.5 at% or less than the stoichiometric composition is formed on the InSb compound semiconductor crystal film. Wherein the excess In is removed by treating the InSb thin film substrate with an acid aqueous solution. 2. An InSb compound semiconductor crystal having a stoichiometric composition is formed by laminating an Sb film as a first layer and an In film as a second layer with a predetermined thickness on a substrate via at least one insulating film. After the formation of the film, an I content of 0.5 at% or more and 2.5 at% or less based on the stoichiometric composition is formed on the InSb compound semiconductor crystal film.
A method for producing an InSb thin film substrate, comprising forming an n-excess InSb-based film, and thereafter treating the surface with an aqueous acid solution to remove the excess In. 3. The method for producing an InSb thin film substrate according to claim 1, wherein said acid is an aqueous solution containing at least one of sulfuric acid and hydrochloric acid. 4. An insulating film in contact with said InSb compound semiconductor crystal film is made of silicon oxide, aluminum oxide, glass,
3. The method for producing an InSb thin film substrate according to claim 2, wherein the film is any one of films mainly composed of aluminum nitride, silicon nitride, tantalum nitride, and titanium nitride.