KR100849685B1 - Preparation method of selective nanowire using patterning of seed layer - Google Patents

Abstract

A method for preparing zinc oxide nanowires is provided to produce well-arranged zinc oxide nanowires by a few processes under an atmosphere similar to ambient temperature and atmospheric pressure. A method for preparing zinc oxide nanowires(8) includes the steps of: (i) forming a patterned photoresist layer(6) on a silicon substrate(2) using a nano-imprint method; (ii) after the step (i) is completed, applying zinc oxide seeds onto the substrate to form a zinc oxide seed layer(4); (iii) after the step (ii) is completed, removing the photoresist layer and the seed layer formed on the photoresist layer together; and (iv) after the step (iii) is completed, growing the zinc oxide seeds applied onto the silicon substrate. Further, a thickness of the zinc oxide seeds is 30 to 1000 nm.

Description

Preparation Method of Selective Nanowire Using Patterning of Seed Layer

1 is a process chart showing a method for producing zinc oxide nanowires according to the present invention.

<Description of the symbols for the main parts of the drawings>

2: silicon substrate 4: seed layer

6: photoresist layer 8: zinc oxide nanowires

The present invention relates to a method for producing zinc oxide (ZnO), specifically zinc oxide nanowires, and more particularly, to form a patterned photoresist layer using a nanoimprint method on a silicon substrate, the patterning is completed Zinc oxide seed is applied on the silicon substrate to form a seed layer, and then the photoresist layer and the seed layer formed on the photoresist layer are removed, and the seed remaining on the silicon substrate from which the photoresist layer and the seed layer are removed. A method for producing zinc oxide nanowires comprising growing a seed of a layer.

Nano-sized materials with small diameters have emerged as a very important field in the recent scientific community because of their new physical and chemical properties, namely their unique electrical, optical and mechanical properties. The research on nanostructures that have been carried out to date shows new possibilities such as quantum size effects and the possibility of new optical device materials of the future.

Among these nanostructures, nanowires exhibit various physical and chemical characteristics because they have a much larger surface / mass ratio than bulk materials, and can be applied to environmental materials as well as optical devices including nanoelectronic devices and semiconductor light emitting devices. In particular, in the case of semiconductor nano-compounds, not only single electron transistor (SET) devices but also new optical device materials are attracting attention.

Therefore, the use of such nanostructures, in particular nanowires, enables the implementation of more advanced and miniaturized electronic, electrochemical and optical devices, as well as the implementation of new features and structures that were previously impossible. For example, when zinc oxide is formed in the form of nanowires, it can be used as a photocatalyst using chemical reactions occurring on the surface, or as an optoelectronic device using optical properties resulting from defects on the surface.

Meanwhile, examples of nanostructures known to date include quantum dots, nano powders, nanowires, nanotubes, quantum wells, nano thin films, and nanocomposites. As described above, the above-described nanostructures may be made of various materials such as Zn, Si, Ge, GaN, GaAs, and the like, in the case of manufacturing nanostructures, particularly nanowires using zinc (Zn). Zinc oxide nanowires can be prepared by oxidizing zinc.

Here, the zinc oxide has a wide bandgap of 3.37 eV at room temperature, and has a large exciton (exciton) binding energy of 60 meV, which is larger than the thermal energy of 24 meV, thereby facilitating light emission in the ultraviolet region. Therefore, the above-described zinc oxide has attracted much attention as an optical device such as an ultraviolet light emitting diode (Ultraviolet LED) or a laser diode (LD) because of its excellent optical properties.

In particular, zinc oxide has been widely used in various fields such as high-temperature, high-voltage electrical and electronic devices, surface acoustic wave devices, piezoelectric devices, gas sensors, and transparent conductive films as broadband semiconductor materials. Although it has been utilized, in recent years, as epitaxial growth technology is developed, new application fields are being explored, and researches on a method for manufacturing zinc oxide having a low dimensional structure, particularly with respect to nano-optical devices, are being actively conducted.

As an example of a method for manufacturing a nanowire as a nanostructure made of zinc oxide, carbon thermal reduction (CVD) or chemical vapor deposition (CVD) is known, and the zinc oxide nanowires prepared using the same Applicability has been confirmed with devices and chemical sensors.

However, since the nanostructures in the form of nanowires are very fine and require a technique such as e-beam lithography to be mobilized in order to realize the device, there is a problem that alignment and assembly are not easy. Development of used device and product is not easy. Accordingly, there is an urgent need to develop a technology for forming a homogeneous nanowire so that the alignment state of the nanowire is good.

On the other hand, zinc oxide manufacturing methods of nanostructures known to date include organometallic chemical vapor deposition (MOCVD), molecular beam deposition, sol-gel deposition, sputtering, reaction evaporation, spray pyrolysis or pulse There is a laser deposition method, and as such an example, Korean Patent Publication No. 2005-0005122 discloses a method of forming zinc oxide nanowires on a surface by oxidizing zinc particles in air / atmospheric pressure, Korean Patent Publication No. 2003 -0060619 discloses a method for producing zinc oxide-based nanowires by organometallic chemical vapor deposition, and Korean Patent Laid-Open No. 2005-0010601, which discloses zinc gas produced by a reduction reaction between zinc oxide powder and graphite on a silicon substrate. A method of making a nanostructure by deposition is disclosed.

However, the aforementioned methods require complicated steps such as controlling the vacuum condition, controlling the gas partial pressure, and / or controlling the temperature, or requiring separate steps such as purchasing the specimen and pretreating the specimen. have. Therefore, in order to more easily manufacture zinc oxide nanostructures, specifically, zinc oxide nanowires, it is required to develop a process capable of manufacturing nanowires in an atmosphere similar to room temperature and / or atmospheric pressure.

Moreover, in implementing zinc oxide into devices, it is important to form nanowires at desired positions in addition to good alignment and formation of homogeneous nanowires. However, when zinc oxide nanowires are formed on a silicon substrate, many nanowires are disposed in an unusable region, which is more discarded than the nanowires used in the device in the process of realizing the nanowires. It is difficult to provide.

Therefore, the formation of nanowires in the desired region as desired alignment forms not only saves wasted resources in implementing the device, but also facilitates device implementation and provides a homogeneous silicon surface in areas other than nanowires. Could be.

In particular, the current semiconductor device manufacturing technology is based on the top-down method based on the lithography technology described above, but the manufacturing method of the nanowire device is based on the voluntary formation process. Based on the Bottoom-Up method.

Here, the batum-up method is a method of forming a nano-sized structure using the bonding force between atoms existing in nature and arranging the structure in such a structure to synthesize a small nano-sized material composed of several atoms. Compared to the top-down method, it not only has the advantage of simplifying the existing process but also generally has high crystallinity, therefore, it is necessary to manufacture high quality devices with improved optical and electrical properties. It is possible.

Despite these advantages, the reason why the top-down method is widely used in the manufacture of semiconductor devices to date is that nanowires can be formed in desired areas through lithography.

Accordingly, the inventors of the present invention form a patterned photoresist layer using a nanoimprint method on a silicon substrate while repeatedly researching to overcome the above-mentioned problems, and seed the zinc oxide on the silicon substrate on which the patterning is completed. applying a seed to form a seed layer, removing the photoresist layer and the seed layer formed on the photoresist layer, and growing the seed layer remaining on the silicon substrate from which the photoresist layer and the seed layer are removed. The present invention has been completed by contemplating that homogeneous zinc oxide nanowires having good alignment in selected areas can be produced.

The present invention was derived to overcome the above-mentioned problems, and formed a patterned photoresist layer on a silicon substrate using a nanoimprint method, and seeded by applying a zinc oxide seed on the silicon substrate on which the patterning was completed. After forming the layer, the photoresist layer and the seed layer formed on the photoresist layer are removed, and the seeds of the remaining seed layer are grown on the silicon substrate from which the photoresist layer and the seed layer are removed, and then, at an ambient temperature and normal pressure. There is a technical problem to provide a method for producing homogeneous zinc oxide nanowires well aligned with only a few processes.

The present invention includes a patterning step of forming a patterned photoresist layer on a silicon substrate using a nanoimprint method; Ii) applying a zinc oxide seed to form a zinc oxide seed layer after the patterning step of step iii) is finished; Iii) removing the photoresist layer and the seed layer formed on top of the photoresist layer after step ii) is finished; And iii) a zinc oxide growth step of growing a zinc oxide seed coated on a silicon substrate after the step iii) is completed.

Zinc oxide nanowires (nanowire) according to the present invention is a zinc oxide nanocrystals in the form of a wire having a direction around one axis, the oxidation of the present invention any nanowires or nanowires commonly used in the art Zinc nanowires.

Here, the zinc oxide nanowires may be manufactured at a specific position of the silicon substrate, that is, at a selected position. In the present invention, the zinc oxide nanowires manufactured at the selected position will be referred to as specifically selective zinc oxide nanowires. do.

The zinc oxide seed according to the present invention is applied on a silicon substrate so that the zinc oxide nanowires are grown in a selective direction from the seed, and the thickness thereof may be adjusted according to the diameter and length of the nanowire to be manufactured. have.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings. However, the following description is only for describing the present invention in detail and does not limit the scope of the present invention by the following description.

1 is described together with a process diagram showing a method for producing a zinc oxide nanowire according to the present invention.

As shown in FIG. 1, the method for manufacturing the zinc oxide nanowires, and specifically the selective zinc oxide nanowires 8 according to the present invention is as follows.

First) a patterning step of forming a patterned photoresist layer 6 on the silicon substrate 2 using the nanoimprint method;

Ii) applying a zinc oxide seed to form a zinc oxide seed layer (4) after the patterning step of step iii) is finished;

Iii) removing the photoresist layer 6 and the seed layer 4 formed on top of the photoresist layer 6 after step ii) is finished; And

Iii) a zinc oxide growth step of growing the zinc oxide seed applied on the silicon substrate 2 after the step iv) is completed.

Here, in the patterning step of step iii), the photoresist layer 6 is formed on the silicon substrate 2 using the nanoimprint method, and at the same time, the photoresist layer 6 formed on the silicon substrate 2 is patterned. As the patterning method used for this purpose, any one may be used. In this case, since the nanoimprint method forms the photoresist layer 6 together with patterning, the manufacturing cost is reduced since the process is simpler than the conventional exposure technique in which the photoresist layer 6 is formed and then patterned. Has a higher degree of integration.

The method for forming the zinc oxide seed layer 4 of step ii) according to the present invention is any conventional method in the art for applying zinc oxide seeds on a silicon substrate 2 comprising a patterned photoresist layer 6. Although not specifically limited, Preferably, zinc oxide seed is apply | coated with RF sputter | spatter or the like.

On the other hand, removing the photoresist layer 6 and the seed layer 4 formed on top of the photoresist layer 6 of step iii) according to the present invention is a photoresist removal method commonly used in the art, for example Any method of removing photoresist using a sulfuric acid hydrogenperoxide mixture (SPM) or piranha may be used, but the photoresist is oxidized by oxidation of ozone dissolved in an aqueous solution using ozone, a powerful oxidizing agent. And a method of dissolving and removing or oxidizing and dissolving the photoresist using a PR remover. Here, the seed layer 4 formed on top of the photoresist layer 6 according to the present invention is removed together with the photoresist layer 6 being removed.

The zinc oxide growth step of step iii) according to the present invention may be used as long as it is a zinc oxide growth method commonly used in the art, but it is recommended to use a solution method.

Specifically describing the solution method as a method of growing a zinc oxide seed according to the present invention, a silicon substrate on which a zinc oxide seed is applied to form a zinc oxide seed layer 4 is 40 to 90 ° C, preferably 50 to It is composed of immersion in an aqueous solution comprising zinc salt, hydroxide and ammonium groups maintained at pH 10-13 having a temperature of 80 ° C, particularly preferably about 60 ° C, for 1-7 hours, preferably about 6 hours.

At this time, the aqueous solution containing the zinc salt, hydroxyl group and ammonium group is 0.8 to 1% by weight of zinc nitrate and 1 to 6% by weight of ammonium hydroxide mixture based on the total weight of the aqueous solution; Or 1-3 wt% zinc sulfate, 1-3 wt% ammonium chloride and 2-10 wt% sodium hydroxide mixture; Or from 6 to 8% by weight of zinc acetate, from 6 to 12% by weight of ethylenediamine and from 1 to 7% by weight of sodium hydroxide, the solvent used being water, preferably resisting 17 to 18 MΩ / cm ^2. It is better to use ultrapure water.

The particularly preferred pH of the aqueous solution comprising the zinc nitrate and ammonium hydroxide mixture is about 10.3, the particularly preferred pH of the aqueous solution comprising zinc sulfate, ammonium chloride and sodium hydroxide mixture is about 10.6, zinc acetate, ethylenediamine And particularly preferred pH of the aqueous solution comprising a sodium hydroxide mixture is about 12.0.

In particular, in manufacturing the zinc oxide nanowires 8 according to the present invention, the pH range in which the diameter and length of the zinc oxide nanowires 8 produced in accordance with the temperature is limited is limited, zinc oxide according to the present invention Zinc oxide nanowire growth is optimized with each mixture pH mentioned above in the production temperature range of the nanowire 8.

In addition, in the production of zinc oxide nanowires 8 through zinc oxide growth according to the present invention, the solution method is zinc oxide nanowires prepared according to the thickness of the zinc oxide seed layer 4 in addition to the pH and temperature ( 8) the diameter and length can be controlled. As the thickness of the zinc oxide seed layer 4 formed on the silicon substrate 2 increases, the length of the zinc oxide nanowire 8 decreases, and the diameter Increases together.

In particular, when the thickness of the zinc oxide seed layer 4 formed on the silicon substrate 2 is 300 nm or less, the length of the zinc oxide nanowires 8 produced according to the thickness of the seed layer is shortened linearly, and zinc oxide When the thickness of the seed layer 4 is 300 nm or more, the length of the zinc oxide nanowires 8 to be produced becomes substantially constant, and the diameter thereof increases logarithmically.

However, when the thickness of the zinc oxide seed layer 4 is 5 nm or less, the zinc oxide nanowires 8 are not formed.

Therefore, in the method for producing the zinc oxide nanowire 8 according to the present invention, the thickness of the zinc oxide seed layer 4 formed on the silicon substrate 2 should be at least 5 nm or more, preferably around 300 nm, in particular Preferably it is 30-1000 nm.

As described above, those skilled in the art will understand that the present invention can be implemented in other specific forms without changing the technical spirit or essential features. Therefore, the exemplary embodiments described above are to be understood as illustrative in all respects and not as restrictive. The scope of the present invention should be construed that all changes or modifications derived from the meaning and scope of the appended claims and equivalent concepts thereof are included in the scope of the present invention rather than the above detailed description.

The present invention provides a small number of processes by forming a zinc oxide seed layer on a patterned photoresist layer formed on a silicon substrate and then removing the photoresist layer to produce zinc oxide nanowires in an atmosphere similar to room temperature and pressure in a selected region. It is effective to produce a homogeneous zinc oxide nanowires aligned well.

Claims (5)

Iii) a patterning step of forming a patterned photoresist layer on the silicon substrate using a nanoimprint method; Ii) applying a zinc oxide seed to form a zinc oxide seed layer after the patterning step of step iii) is finished; Iii) removing the photoresist layer and the seed layer formed on top of the photoresist layer after step ii) is finished; And Iii) a zinc oxide nanowire comprising a zinc oxide growth step of growing a zinc oxide seed coated on a silicon substrate after step iii) is completed. The method of claim 1, The zinc oxide nanowires manufacturing method, characterized in that the thickness of the zinc oxide seed layer of step ii) is 30 to 1000nm. The method of claim 1, Removing the photoresist layer and the seed layer formed on top of the photoresist layer of step iii) by oxidizing and dissolving the photoresist by oxidizing ozone dissolved in an aqueous solution using ozone as an oxidizing agent Method for producing zinc nanowires.  The method of claim 1, The zinc oxide growth step of step iii) is performed for 5 to 7 hours in an aqueous solution containing zinc salt, hydroxide and ammonium group, which is maintained at a pH of 10 to 13 having a temperature of 40 to 90 ° C on a silicon substrate coated with zinc oxide seeds. Method for producing a zinc oxide nanowires, characterized in that the immersion. The method of claim 4, wherein The aqueous solution containing the zinc salt, hydroxyl group and ammonium group is 0.8 to 1% by weight of zinc nitrate and 1 to 6% by weight of ammonium hydroxide mixture based on the total weight of the aqueous solution; Or 1-3 wt% zinc sulfate, 1-3 wt% ammonium chloride and 2-10 wt% sodium hydroxide mixture; Or 6 to 8% by weight of zinc acetate, 6 to 12% by weight of ethylenediamine and 1 to 7% by weight of sodium hydroxide mixture.

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