KR101115389B1 - Solution phase preparation method of group ii-vi compound semiconductor thin film and group ii-vi compound semiconductor thin film prepared thereby - Google Patents

Abstract

PURPOSE: A solution phase preparation method of a group ii-vi compound semiconductor thin film and a group ii-vi compound semiconductor thin film prepared thereby are provided to form a semiconductor film in a substrate without a high process vacuum deposition equipment by using a liquid manufacturing process. CONSTITUTION: A solution of A is coated in a substrate through spin-coating. The substrate coated with the solution of A is dried under 200°C~250°C for more than one minute. A solution of B is coated in the substrate coated with the solution through spin-coating. The substrate coated with the solution of B is dried under 200°C~250°C for more than one minute. The substrate surface is cleaned and dried.

Description

SOLUTION PHASE PREPARATION METHOD OF GROUP II-VI COMPOUND SEMICONDUCTOR THIN FILM AND GROUP II-VI COMPOUND SEMICONDUCTOR THIN FILM PREPARED THEREBY}

The present invention relates to a method for producing a solution phase of a group II-VI compound semiconductor thin film, and more specifically, to a group II Elemental Precursors and Group VI Elements By repeatedly depositing a solution in which a precursor is dissolved in a viscous polyhydric alcohol solvent several times, it is deposited on a substrate, and then annealing the formed thin film, thereby rapidly growing the thin film and reducing the cost and time required for the process. A method for producing a solution phase of a group compound semiconductor thin film.

In general, most semiconductor processes rely mostly on equipment capable of vacuum processing. In addition, in the situation where the size of the substrate is being enlarged, the extra large size of essential equipment such as thin film deposition equipment is also progressed, resulting in a high manufacturing process cost. As a method of overcoming such a problem, a method of proceeding a manufacturing process to a liquid manufacturing process (Solution Process) that does not require vacuum equipment has been proposed.

Research on depositing semiconductor materials using liquid phase manufacturing processes has already been reported by research groups at home and abroad. Particularly, in the solar cell field, devices were fabricated by depositing materials such as CdS or CdSe, which are used as buffer layers of CIGS solar cells, in the liquid phase manufacturing process since the early 1990s. , Galvanic deposition, chemical bath deposition (CBD), and successive ionic layer adsorption and reaction (SILAR) have been proposed. In addition, the liquid crystal manufacturing process is used in various applications such as ferroelectric materials for solar applications and electrode layers of solar cells to replace conventional deposition methods.

In the typical SILAR method of the liquid phase manufacturing process, since the monomolecular layer adsorption and reaction, the thin film growth rate is very slow, so that a considerable time is required to obtain a thin film having a predetermined thickness.

The present invention has been made to solve the above problems, an object of the present invention is to provide a method for producing a solution phase of the II-VI compound semiconductor thin film to provide a fast film growth rate to obtain a thin film of the desired thickness within a short time There is.

It is another object of the present invention to provide a method for producing a solution phase of a group II-VI compound semiconductor thin film which can be carried out in a simple process manner to reduce cost and time.

In order to achieve the above object, an aspect of the present invention, (S1) applying a solution A formed by dissolving a component selected from Group II element precursor or Group VI element precursor in a viscous polyhydric alcohol solvent; (S2) drying the substrate coated with the solution A; (S3) applying the solution B formed by dissolving the remaining components not selected in the step (S1) in the solvent to the solution A-coated substrate; (S4) drying the substrate obtained in the step (S3); And (S5) washing and drying the surface of the substrate, and repeating the step (S1) to (S5) one or more times in one cycle, followed by annealing the resulting thin film. Provided is a method for producing a solution phase of a semiconductor thin film.

According to the present invention, a thin film having a desired thickness can be obtained by repeating the steps (S1) to (S5) one or more times. Hereinafter, the steps (S1) to (S5) of the present invention will be described in detail.

In the step (S1) of the present invention, a selected component of a Group II element precursor or a Group VI element precursor is dissolved in a viscous polyhydric alcohol solvent to form a solution A, and the formed solution A is applied to a substrate. The application method is not particularly limited as long as the thin film thickness of the precursor solution can be kept constant so that the amount of solute supplied on the substrate can be fixed. As such a coating method, a spin coating method, a dipping method, a doctor blade method, or the like can be used. Particularly preferably, a spin coating method can be used. When using the spin coating method, it is possible to control the thickness of the thin film formed by adjusting the revolutions per minute (rpm) during spin coating. Application methods, in particular spin coating methods, are well known to those skilled in the art. Therefore, in the present specification, a detailed discussion other than the above-mentioned information is omitted. Here, the group II element precursor and the group VI element precursor can use any material known in the art without particular limitation. As the Group II element precursor, nitrates of the Group II elements, hydrochloride (Cl ⁻ ), fluoride (Br ⁻ ) and iodide salt (I ⁻ ) are preferable, and nitrates of the Group II element are particularly preferable. In general, nitrates are easily decomposed into N ₂ , O ₂ , NO, etc., when heated to a high temperature, so that it is easy to remove unnecessary components. As group VI element precursor, the alkali metal salt of group VI element is preferable, and the sodium salt of group VI element is especially preferable.

According to the present invention, a coating film having a predetermined thickness can be formed by using a viscous polyhydric alcohol solvent as a solvent. As the viscous polyhydric alcohol solvent, ethylene glycol (EG) or propylene glycol (PG) is particularly preferable. Since the solvent used in the present invention is viscous, if the number of revolutions per hour is determined during spin coating, the solution may be coated with a constant thickness. Therefore, the number of rotations during spin coating may act as a variable for determining the thickness. The number of rotations during spin coating according to the present invention is preferably 50 to 5000 rpm, particularly preferably 2000 rpm in consideration of the uniformity of the thin film and the growth rate of the thin film.

According to the present invention, the substrate can use any material known in the art without particular limitation. For example, a glass plate or a silicon substrate can be used. In order to form the desired semiconductor thin film on a substrate well, the thing in which molybdenum was deposited on the glass plate or the silicon substrate, or the substrate surface substituted with the thiol group can be used. In the case of a thin film such as ZnSe, a ZnS thin film may be formed in advance on the substrate surface.

In step (S2) of the present invention, the substrate coated with solution A is dried. Since the solute reacts with the surface of the substrate in this step, drying temperature and drying time are very important variables. In an atmosphere in which oxygen or moisture is controlled, a drying temperature of 200 ° C to 250 ° C and a drying time of 1 minute or more, particularly 1 minute to 10 minutes, are suitable. It is especially preferable to dry for 1 to 10 minutes at the temperature of 200 degreeC. The reason why the drying temperature is required to be 200 ° C. or higher is that it must be higher than the boiling point of the solvent at normal pressure, and the reason for the temperature lower than 250 ° C. is that the thin film is not smoothly formed by annealing when the drying temperature is too high. Since the drying time is the reaction time of the solute and the surface of the substrate, it is obvious to the person skilled in the art that the reaction will occur well as the reaction time is longer. After the reaction, by-products may be formed in addition to the components constituting the thin film or residues which have not reacted may be present, but may proceed directly to the step S3 without additional washing.

In step (S3) of the present invention, the solution B formed by dissolving the remaining components not selected in step (S1) in a solvent is applied to a substrate coated with solution A. At this time, the solvent is the same as that used in the step (S1), it is possible to apply the solution in the same manner as the (S1) step. When solution A is prepared by dissolving the group II element precursor in the solvent in step (S1), solution B of step (S3) is prepared by dissolving the group VI element precursor in the solvent. On the other hand, when the solution A is prepared by dissolving the group VI element precursor in the solvent in step (S1), the solution B of step (S3) is prepared by dissolving the group II element precursor in the solvent.

Since solution A of constant thickness is present on the substrate and solution B of constant thickness is supplied, the amount of solute supplied on the substrate is constant each time. Here, by adjusting the concentration of the solution A and B it is possible to control the amount of precursors participating in the thin film formation reaction. Therefore, the concentration of solution A and B may act as a film thickness control factor. In the present invention, the concentrations of the solutions A and B can be appropriately selected by those skilled in the art according to the desired thin film thickness, preferably 0.001M to 0.5M, and particularly preferably 0.1M, but are not particularly limited.

In step (S4) of the present invention, the substrate obtained in step (S3) is dried. In this step, since the solute supplied in the step (S3) reacts with the surface of the substrate, the drying temperature and the drying time are very important variables. Drying temperature and drying time are as defined in step (S2). After the reaction, in addition to the components constituting the thin film, by-products may be formed or residues that do not react may be present.

In step (S5) of the present invention, the substrate surface is washed and dried. Specifically, to remove excess solutes or by-products of the reaction that participate in the reaction by performing a dip method of dipping the substrate in a solvent or by supplying a sufficient amount of solvent to the substrate surface according to any known method. can do. Here, the solvent is generally used a solvent used for the preparation of the solution, but may be a solvent, such as distilled water, so that the resulting reaction by-products or unreacted precursors can be dissolved because it is used for washing. Drying can be carried out in any manner by one skilled in the art, and is not particularly limited. However, the drying temperature should be maintained at or above the boiling point of the solvent used in the washing step, preferably at 200 ° C., so that the thin film is smoothly formed during subsequent annealing.

After the step (S1) to (S5) of the present invention is repeated one or more times in one cycle, the thin film may be formed and densified by further annealing. When using a conventional furnace (annealed), annealing is carried out at 350 ℃ to 450 ℃, preferably 400 ℃ for 2 hours under an inert gas, for example, nitrogen atmosphere. It is also possible to use rapid thermal annealing (RTA) capable of rapid temperature rise. If RTA is used, it can be carried out in a short time at a higher temperature than in a conventional furnace, and it is preferable to process at 500 ° C. to 550 ° C., especially at 550 ° C. for 3 to 5 minutes, in this case, the same as that of 400 ° C. for 2 hours. An effect can be obtained, which has advantages such as shortening of processing time.

Another aspect of the present invention provides a method for producing a solution phase of a II-VI compound semiconductor thin film, further comprising the step of washing and drying the substrate surface between steps (S2) and (S3). . After the reaction of the step (S2), in addition to the components constituting the thin film may be a by-product formed or remain unreacted. Therefore, after each solution is applied alternately, if the washing and drying steps are performed for each application, the reaction may occur effectively and the thin film may be grown more uniformly.

The binary II-VI compound semiconductor thin film prepared according to the present invention comprises a metal selected from the group consisting of Zn, Cd, Sn, Cu and Ag and a chalcogen selected from the group consisting of S, Se and Te. In one embodiment, the binary II-VI compound semiconductor thin film according to the present invention may be represented by the formula MX, wherein M is a metal such as Zn, Cd, Sn, Cu, X is chalcogen, For example, S, Se, Te. In another embodiment, the binary II-VI compound semiconductor thin film according to the present invention may be represented by the formula M ₂ X, wherein M is a metal such as Ag and X is a chalcogen such as S, Se, Te.

According to the present invention, the binary II-VI compound semiconductor thin film can be produced at a high growth rate, for example, can be grown to about 33 nm per cycle. Repeating the cycle 30 times can be produced to a thickness of about 1㎛. The binary II-VI compound semiconductor thin film manufactured according to the present invention may vary depending on the process time and the application of the device to which the thin film manufactured in the present invention is applied, but the thin film thickness may be 2 μm or less.

Another aspect of the present invention provides a II-VI compound semiconductor thin film prepared according to the method of the present invention. Specifically, the group II-VI compound semiconductor thin film of the present invention is a solution A formed by dissolving a selected component of a Group II element precursor or a Group VI element precursor in a viscous polyhydric alcohol solvent, and the remaining components not selected are the solvent. The solution B formed by dissolving in the substrate and alternately performing a process of drying and then washing the surface of the substrate and repeated the process of drying at least one time, characterized in that the prepared by annealing.

As described above, according to the solution phase manufacturing method of the II-VI compound semiconductor thin film of the present invention, the advantage of being able to form the thin film thin film on the substrate without using expensive vacuum deposition equipment by using the liquid phase manufacturing process There is this.

In addition, the solution phase manufacturing method of the II-VI compound semiconductor thin film of the present invention has the advantage that can be grown quickly to reduce the cost and time required for the process.

1 is a photograph of the surface (a) and the cross-section (b) of the CuSe thin film formed in Example 1-1 by scanning electron microscope (SEM).
2 is a photograph taken of the surface (a) and the cross-section (b) of the CuSe thin film formed in Example 1-2 with a scanning electron microscope.
3 is a graph showing the XRD pattern of the formed CuSe thin film before and after the N ₂ annealing treatment.
4 is a graph showing the XRD pattern of the CuSe thin film according to the N ₂ annealing treatment temperature.
5 is a photograph taken of the surface (a) and the cross-section (b) of the CuSe thin film formed in the comparative example by a scanning electron microscope.
6 is N ₂ in Example ₂ It is a graph which shows the XRD pattern of the ZnSe thin film formed before and after annealing treatment.

Hereinafter, preferred examples are provided to aid the understanding of the present invention, but the following examples are merely for exemplifying the present invention, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and spirit of the present invention. It is natural that such variations and modifications fall within the scope of the appended claims.

Example  One: Cuse  Manufacture of thin film

Solutions A and B used in Example 1 to prepare a CuSe thin film, the substrate is as follows:

? Solution A: 0.1 M solution prepared by dissolving 0.233 g of Cu (NO ₃ ) ₂ (MW 232.59, purity 99.999%) in 10.0 ml of propylene glycol (PG)

? Solution B: 0.1 M solution prepared by dissolving 0.125 g Na ₂ Se in 10.0 ml PG

Substrate: Molybdenum-deposited glass plate

Example  1-1. Solution A coating followed by Solution B coating

To repeat the step S1 to S5 described in Table 1 with one cycle 100 times.

step
Experimental conditions Solution type Revolutions Solution concentration Temperature time S1 Solution A Coating 2000 rpm 0.1 M - S2 reaction - 200 ℃ 1 minute S3 Solution B Coating 2000 rpm 0.1 M - S4 reaction - 200 ℃ 1 minute S5 Washing and drying - Solvent use 200 ℃

Solution A was spin coated onto the substrate for 1 minute at a rotational speed of 2000 rpm. The substrate coated with solution A was dried at 200 ° C. for 1 minute. During drying, the solute Cu (NO ₃ ) ₂ reacts with the substrate. Solution B was spin coated on the substrate for 1 minute at 2000 rpm. The substrate coated with solution B was dried at 200 ° C. for 1 minute. During drying, Cu (NO ₃ ) ₂ present on the surface reacts with Na ₂ Se supplied to form CuSe and NaNO ₃ as a by-product.

Scheme: Cu (NO ₃ ) ₂ + Na ₂ Se → CuSe (thin film) + 2NaNO ₃ (by-product)

The substrate on which CuSe was formed was dipped in propylene glycol as a solvent by a dip method and then dried. After 100 times in this manner, annealing was carried out in such a manner that the thin film was densified at 400 ° C. for 2 hours in a nitrogen atmosphere. SEM photographs of the surface and cross section of the formed CuSe thin film are shown in FIG. 1. It can be seen from FIG. 1 that a uniform CuSe thin film of plate or needle shape was formed.

Example  1-2. Solution A coating followed by Solution A coating

The same procedure as in Example 1-1 was conducted except that solution B was spin coated before solution A. The annealing treatment was repeated 100 times with steps S1 to S5 described in Table 2 below as one cycle.

step
Experimental conditions Solution type Revolutions Solution concentration Temperature time S1 Solution A Coating 2000 rpm 0.1 M - S2 reaction - 200 ℃ 1 minute S3 Solution B Coating 2000 rpm 0.1 M - S4 reaction - 200 ℃ 1 minute S5 Washing and drying - Solvent use 200 ℃

SEM photographs of the surface and cross section of the formed CuSe thin film are shown in FIG. 2. It can be seen from FIG. 2 that a uniform CuSe thin film of plate or needle shape was formed.

Example  1-3. Perform additional wash

The same procedure as in Example 1-1 was conducted except that an additional washing step was performed between steps S2 and S3. The annealing treatment was repeated 100 times with steps S1 to S5 described in Table 3 below as one cycle.

step Contents Solution type Revolutions Solution concentration Temperature time S1 Solution A Coating 2000 rpm 0.1 M - S2 reaction - 200 ℃ 1 minute S2 .5 Washing and drying - Solvent use 200 ℃ S3 Solution B Coating 2000 rpm 0.1 M - S4 reaction - 200 ℃ 1 minute S5 Washing and drying - Solvent use 200 ℃

XRD patterns of the formed CuSe thin film before and after the annealing treatment are shown in FIG. 3. It can be seen from FIG. 3 that annealing treatment is essential to form a CuSe thin film completely.

Example  1-4. Annealing  Preparation of Thin Films with Temperature Changes

Except that the annealing treatment at 500 ℃ and 600 ℃ under a nitrogen atmosphere was carried out in the same manner as in Example 1-3, the XRD pattern of the formed CuSe thin film was investigated. The results are shown in FIG. When annealing at 500 ° C and 600 ° C, it can be seen from FIG. 4 that no uniform CuSe thin film was formed.

Comparative example Without washing steps Cuse  Manufacture of thin film

Except not performing the step S5 washing step was performed in the same manner as in Example 1-1, the SEM photograph of the surface and cross-section of the formed CuSe thin film is shown in FIG. It can be seen from FIG. 5 that the CuSe thin film is not formed when the process of forming the thin film without the washing step is repeated.

Example  2: ZnSe  Manufacture of thin film

Solutions A and B used in Example 2 to prepare a ZnSe thin film, the substrate is as follows:

? Solution A: 0.1 M solution prepared by dissolving 0.233 g of Zn (NO ₃ ) ₂ (MW 189.40, purity 99.999%) in 10.0 mL of ethylene glycol (PG)

? Solution B: 0.1 M solution prepared by dissolving 0.125 g of Na ₂ Se in 10.0 ml of ethylene glycol

Substrate: A glass plate substituted with a thiol group

Using the solutions A and B defined in Example 2, the same procedure as in Example 1-3 was conducted except that the drying time was fixed at 5 minutes. After repeating 30 times with one cycle of steps S1 to S5 shown in Table 4 it was annealed at 400 ℃.

step Contents Solution type Revolutions Solution concentration Temperature time S1 Solution A Coating 2000 rpm 0.1 M - S2 reaction - 200 ℃ 5 minutes S2 .5 Washing and drying - Solvent use 200 ℃ S3 Solution B Coating 2000 rpm 0.1 M - S4 reaction - 200 ℃ 5 minutes S5 Washing and drying - Solvent use 200 ℃

The XRD pattern of the formed ZnSe thin film before and after the annealing treatment is shown in FIG. 6. Peaks corresponding to selenium were observed before the annealing treatment, but after the annealing treatment, it was confirmed that a complete ZnSe thin film was formed.

Claims (15)

As a solution phase manufacturing method of a II-VI compound semiconductor thin film,
(S1) applying a solution A formed by dissolving a selected component of a Group II element precursor or a Group VI element precursor in a viscous polyhydric alcohol solvent to a substrate using a spin coating method;
(S2) drying the substrate coated with the solution A at a temperature of 200 ° C. to 250 ° C. for at least 1 minute;
(S3) applying the solution B formed by dissolving the remaining components not selected in the step (S1) in the solvent to the solution A-coated substrate by spin coating;
(S4) drying the substrate obtained in the step (S3) at a temperature of 200 ° C. to 250 ° C. for at least 1 minute; And
(S5) cleaning and drying the substrate surface
And a step of (S1) to (S5) as one cycle, repeating one or more times, and then annealing the resulting thin film. The method of claim 1,
Between the step (S2) and (S3),
The method of manufacturing a solution phase of a II-VI compound semiconductor thin film further comprising the step of washing and drying the substrate surface. delete delete The method of claim 1,
The (S2) and (S4) step is a solution phase manufacturing method of a II-VI compound semiconductor thin film, characterized in that for 1 to 10 minutes to dry at a temperature of 200 ℃. The method of claim 1,
The viscous polyhydric alcohol solvent is ethylene glycol or propylene glycol solution of the II-VI compound semiconductor thin film production method. The method of claim 1,
The molar concentration of the said solution A and the solution B is 0.001M-0.5M, The solution phase manufacturing method of the II-VI compound semiconductor thin film characterized by the above-mentioned. The method of claim 1,
The method of annealing the produced Group II-VI compound semiconductor thin film is maintained for 2 hours at 350 to 450 ° C. under an inert gas atmosphere. The method of claim 1,
The method of annealing the produced group II-VI compound semiconductor thin film is maintained at 400 ° C. for 2 hours under a nitrogen atmosphere, so that a method of producing a solution phase of a group II-VI compound semiconductor thin film. The method of claim 1,
The method of annealing the produced group II-VI compound semiconductor thin film is a solution of a group II-VI compound semiconductor thin film, which is treated at 500 ° C. to 550 ° C. for 3 to 5 minutes using rapid thermal annealing. Phase manufacturing method. The method of claim 1,
The II-VI compound semiconductor thin film includes a metal selected from the group consisting of Zn, Cd, Sn, Cu, and Ag, and a chalcogen selected from the group consisting of S, Se, and Te. Solution phase manufacturing method of compound semiconductor thin film. The method of claim 1,
The Group II element precursor is a nitrate, hydrochloride, fluoride or iodide salt of Group II elements, the solution phase of the II-VI compound semiconductor thin film. The method of claim 1,
The Group VI element precursor is a solution phase manufacturing method of a II-VI compound semiconductor thin film, characterized in that the alkali metal salt of the Group VI element. The method of claim 13,
The group VI element precursor is a sodium salt of a group VI element, the solution phase manufacturing method of a II-VI compound semiconductor thin film. Solution A formed by dissolving a selected component of Group II element precursor or Group VI element precursor in a viscous polyhydric alcohol solvent and solution B formed by dissolving the remaining unselected components in the solvent are applied to the substrate by spin coating. A group II-VI compound semiconductor thin film prepared by annealing after repeatedly applying the coating and drying the substrate surface one by one or more times at a temperature of 200 ℃ to 250 ℃ and washing and drying at least one time.

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