Method for forming amorphous tellurium oxide through ultraviolet-ozone treatment, amorphous tellurium oxide formed by using same, and field effect transistor comprising same

Abstract

The present invention relates to: a method for forming an amorphous tellurium oxide through ultraviolet-ozone (UV-O3) treatment, an amorphous tellurium oxide formed by using same; and a field effect transistor comprising same. In the present invention, an amorphous tellurium oxide (TeOx) can be prepared through ultraviolet-ozone treatment of crystalline tellurium (Te). According to the present invention, a simple method can be used to overcome the limitations of existing crystalline tellurium having metalloid characteristics and induce a phase change in tellurium to improve the band gap, and a stable high-performance field effect transistor (FET) having a high on / off ratio and mobility can be manufactured using same.

Description

Method for forming amorphous tellurium oxide through UV-ozone treatment, amorphous tellurium oxide formed using the same, and a field-effect transistor including the same

[0001] The present invention relates to a method for forming amorphous tellurium oxide through ultraviolet-ozone (UV-O3) treatment, an amorphous tellurium oxide formed using the same, and a field-effect transistor including the same. More specifically, the invention relates to a method for forming amorphous tellurium oxide with excellent electrical properties in a simple manner by inducing a phase transition in two-dimensional tellurium through ultraviolet-ozone treatment, an amorphous tellurium oxide formed using the same, and a field-effect transistor including the same.

[0002] A transistor is a device that uses semiconductors to amplify or switch electronic signals and power, and is widely used in various electronic devices such as displays and speakers. Conventional transistors generally used silicon-based semiconductors, but there were limitations such as the need for high-temperature heat treatment during manufacturing, difficulty in applying to 3D semiconductor technology, and low mobility.

[0003] Oxide semiconductors have been proposed as one of the alternatives to silicon-based semiconductors, and oxide semiconductors have advantages in that they have high visible light transmittance, a wide bandgap, and high mobility. However, most oxide semiconductors have n-type characteristics, and p-type oxide semiconductors with a wide bandgap have limitations in that it is difficult to obtain uniform quality and electrical characteristics such as mobility and switching ratio are poor. In this regard, Korean Patent Publication No. 10-2015-0108168 describes a method for fabricating p-type oxide semiconductors by additionally combining Ga with CuS, SnO, ITO, IZTO, IGZO, IZO, etc., but there were limitations in actual process application because a heat treatment process at a high temperature of 300°C or higher is required to achieve high mobility.

[0004] Meanwhile, two-dimensional (2D) semiconductors have the advantage of exhibiting excellent gate control characteristics at atomic layer thickness and improving p-type transistor performance, and in particular, research is being conducted on using tellurium as a material for two-dimensional p-type semiconductors. Two-dimensional tellurium (2D-Te) has advantages in terms of high mobility and excellent stability, but it has disadvantages such as a narrow bandgap energy, a low on / off ratio, and semi-metallic characteristics.

[0005] To overcome these drawbacks, reducing the thickness of 2D tellurium can expand the bandgap and improve the switching ratio, but this can lead to a decrease in mobility and has limitations such as demanding or complex process conditions. For example, the literature [Chunsong Zhao et al., Nature Nanotechnology, volume 15, pages 53-58 (2020)] proposed a technique using thermal evaporation to deposit ultrathin tellurium films on various substrates, but this technique had the disadvantage of requiring an ultra-low temperature of -80°C.

[0006] Therefore, there is a need for the development of technology that can fabricate high-performance p-type semiconductors by expanding the bandgap and improving the on / off ratio while maintaining the stability and mobility of tellurium through a simple process.

[0007] One objective of the present invention is to provide a method for forming amorphous tellurium oxide with excellent electrical properties through a simple process.

[0008] Another objective of the present invention is to provide an amorphous tellurium oxide formed through the above method.

[0009] Another objective of the present invention is to provide a high-performance field-effect transistor comprising the amorphous tellurium oxide.

[0010] To achieve the above objective, the present invention provides a method for forming amorphous tellurium oxide by inducing a phase transition through a UV-Ozone (UV-O3) treatment step in which ultraviolet (UV) rays are irradiated onto a crystalline tellurium material to generate ozone (O3).

[0011] In the present invention, the ultraviolet-ozone treatment step can be performed by irradiating a light source including a wavelength range of 100 to 300 nm.

[0012] In the present invention, the light source may include a wavelength range of 100 to 200 nm and a wavelength range of 220 to 300 nm.

[0013] In the present invention, the phase transition through the ultraviolet-ozone treatment step comprises: a step in which oxygen molecules (O2) are decomposed into oxygen atoms (O) by light source energy including a wavelength range of 100 to 200 nm; a step in which the oxygen atoms (O) combine with oxygen molecules (O2) to form ozone (O3); and a step in which the ozone (O3) is broken down into oxygen molecules (O2) and oxygen radicals (O) by light source energy including a wavelength range of 220 to 300 nm. * A step of decomposing into ); and the oxygen radical (O * This can be carried out through a step in which tellurium ionized by a light source reacts to form tellurium oxide.

[0014] In the present invention, the ultraviolet-ozone treatment step can be performed using an ultraviolet ozone generator comprising a power supply, a low-pressure mercury vapor discharge lamp, a sample tray, and a sealed chamber.

[0015] In the present invention, the ultraviolet-ozone treatment step can be performed for 5 to 60 minutes.

[0016] In the present invention, the bandgap energy (E) of the formed amorphous tellurium oxide g ) can be 1 eV or more.

[0017] In the present invention, the mobility of the formed amorphous tellurium oxide is 100 cm⁻¹ 2 / V·s may be more than

[0018] The present invention also provides an amorphous tellurium oxide formed by the above method.

[0019] The present invention also provides a field-effect transistor using the amorphous tellurium oxide.

[0020] In the present invention, the field-effect transistor may include a lower electrode, a gate insulating film formed on the lower electrode, an amorphous tellurium oxide thin film formed on the gate insulating film, and an upper electrode formed on the amorphous tellurium oxide thin film.

[0021] In the present invention, the on / off ratio of the field-effect transistor is 10 3 It could be more than that.

[0022] In the present invention, amorphous tellurium oxide (TeO₂) is produced through ultraviolet-ozone (UV-O3) treatment of crystalline tellurium (Te). x ) can be formed. According to the present invention, a phase transition can be induced in tellurium in a simple way to overcome the limitations of two-dimensional tellurium with conventional metalloid characteristics and improve the band gap, and by using this, a stable high-performance field-effect transistor (FET) with high switching ratio and mobility can be manufactured.

[0023] FIG. 1 schematically illustrates the process of forming amorphous tellurium oxide according to one embodiment of the present invention.

[0024] FIG. 2 schematically shows the structure of a device used for ultraviolet-ozone treatment in an amorphous tellurium oxide formation process according to one embodiment of the present invention.

[0025] FIG. 3 schematically illustrates an ultraviolet-ozone treatment process according to one embodiment of the present invention.

[0026] FIGS. 4a and 4b respectively show transmission electron microscope (TEM) images of crystalline tellurium (a) before UV-ozone treatment and amorphous tellurium oxide (b) after UV-ozone treatment according to one embodiment of the present invention.

[0027] Figures 5a and 5b respectively show X-ray photoelectron spectroscopy (XPS) data of crystalline tellurium (a) before UV-ozone treatment and amorphous tellurium oxide (b) after UV-ozone treatment according to one embodiment of the present invention.

[0028] Figure 6 shows optical microscope and atomic force microscope images of tellurium according to the UV-ozone treatment time in one embodiment of the present invention.

[0029] Figure 7 shows the results of Raman spectroscopy of amorphous tellurium oxide after UV-ozone treatment in one embodiment of the present invention.

[0030] FIGS. 8a and 8b respectively show an FET device (a) using 2D Te and a-TeO using 2D Te according to an embodiment of the present invention. x For a FET device (b) using [the element], the field-effect mobility (μ) at a temperature of 100 to 370 K eff This shows the results of measuring ).

[0031] FIG. 9 shows 2D Te or a-TeO according to one embodiment of the present invention. x This shows the SBH measurement results according to the gate voltage in the FET device to which it was applied.

[0032] FIG. 10 shows 2D Te or a-TeO according to one embodiment of the present invention. x This is a graph showing the contact resistance measurement results according to gate voltage in an FET device to which the above was applied.

[0033] FIG. 11 shows 2D Te or a-TeO according to one embodiment of the present invention. x I for FET device applyingds -V gs This is a graph.

[0034] FIG. 12 shows a band diagram of the on / off state for an FET device according to one embodiment of the present invention.

[0035] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. The embodiments exemplified below are not intended to limit the scope of the present invention but are provided to explain the present invention to those skilled in the art. In the drawings, the same reference numerals refer to the same components, and the size or thickness of each component may be exaggerated for clarity of explanation.

[0036]

[0037] The present invention relates to a method for forming amorphous tellurium oxide through ultraviolet-ozone (UV-O3) treatment.

[0038] Two-dimensional tellurium (2D Te) is essentially a p-type semiconductor, but at thicknesses of tens of nanometers (nm), it has a low band gap of 0.3 eV and exhibits semi-metallic characteristics. These characteristics of two-dimensional tellurium can act as a limiting factor in the implementation of high-performance field-effect transistors (FETs).

[0039] The present invention aims to solve these problems by inducing a phase transition of crystalline tellurium (Te) into amorphous tellurium oxide (TeO) through an ultraviolet-ozone (UV-O3) treatment process. x It can be changed to ). In the present invention, the bandgap can be improved by inducing a phase transition in tellurium using a simple method, and by using this, a stable high-performance field-effect transistor (FET) with a high on / off ratio and mobility can be manufactured.

[0040] FIG. 1 schematically illustrates the process of forming an amorphous tellurium oxide according to the present invention. The present invention provides a method for forming an amorphous tellurium oxide by inducing a phase transition through a UV-Ozone (UV-O3) treatment step in which ultraviolet rays (UV) are irradiated onto a crystalline tellurium material to generate ozone (O3).

[0041] The above tellurium material is a material containing the element tellurium (Te), and may refer to a material containing not only a single tellurium material but also other elements. For example, the above tellurium material may include Te, MoTe2, WTe2, HfTe5, PtTe2, Bi2Te3, Sb2Te3, PbTe, SnTe, GeTe, Ag2Te, MnBi2Te4, etc.

[0042] In the present invention, the tellurium material may be a two-dimensional tellurium material. Additionally, the tellurium material may be in the form of a thin film having a thickness of, for example, 2 to 100 nm, specifically 5 to 50 nm.

[0043] In the present invention, a phase transition is induced by irradiating the crystalline tellurium material with ultraviolet (UV) light and generating ozone (O3) through UV-Ozone (UV-O3) treatment, thereby forming an amorphous tellurium oxide.

[0044] In the present invention, ultraviolet light is used to provide high-energy photons, which promote a chemical reaction between a tellurium (Te) atom and surrounding oxygen molecules. Accordingly, the lattice structure of the tellurium atom is destroyed and combined with oxygen, thereby overcoming the energy barrier required for the formation of tellurium oxide.

[0045] In the present invention, ozone acts as a powerful oxidizing agent, and when crystalline tellurium is activated by irradiating it with ultraviolet light, ozone reacts with tellurium to form tellurium oxide. Since ozone is more reactive than oxygen molecules, the oxidation process of tellurium can be accelerated through ozone treatment.

[0046] Through the above UV-ozone treatment, the crystal structure of tellurium is destroyed, and tellurium atoms no longer maintain a crystal lattice structure and are arranged in a disordered manner, thereby forming amorphous tellurium oxide.

[0047] In addition, according to the above UV-ozone treatment process, a phase transition begins from the surface of the tellurium, and as the crystalline tellurium changes into amorphous tellurium oxide, the overall thin film thickness increases. This phase transition process is an irreversible reaction, and the tellurium oxide formed according to the present invention does not return to its original crystalline structure.

[0048] The electron affinity of tellurium is <4.8 eV, so the tetravalent / hexavalent ionization of two-dimensional tellurium proceeds due to ultraviolet light and an ozone atmosphere is formed, and after the tellurium is ionized, it reacts with oxygen radicals generated from ozone to form tellurium oxide.

[0049] In the ultraviolet-ozone treatment process of the present invention, as excitation sources, a light source including a wavelength range of 100 to 300 nm may be used, and preferably, a light source including a wavelength range of 100 to 200 nm and a wavelength range of 220 to 300 nm may be used. More preferably, the light source may include a wavelength range of 170 to 200 nm and a wavelength range of 240 to 270 nm.

[0050] Specifically, the ultraviolet-ozone treatment step of the present invention comprises: a step in which oxygen molecules (O2) are decomposed into oxygen atoms (O) by light source energy including a wavelength range of 100 to 200 nm, preferably 170 to 200 nm; a step in which the oxygen atoms (O) combine with oxygen molecules (O2) to form ozone (O3); and a step in which the ozone (O3) is decomposed into oxygen molecules (O2) and oxygen radicals (O) by light source energy including a wavelength range of 220 to 300 nm, preferably 240 to 270 nm. * A step of decomposing into ); and the oxygen radical (O* It may include a step in which tellurium ionized by a light source reacts to form tellurium oxide. For example, a light source having wavelengths of 185 nm and 254 nm may be used as the light source.

[0051] In one embodiment of the present invention, the ultraviolet-ozone treatment can be performed using an ultraviolet-ozone generator having the structure shown in FIG. 2.

[0052] The above ultraviolet ozone generator (100) includes a power supply (110), a low-pressure mercury vapor discharge lamp (120), a sample tray (130), and a sealed chamber (140). Crystalline tellurium is placed in the sample tray (130), and the power supply (110) is driven to generate ultraviolet rays and ozone from the low-pressure mercury vapor discharge lamp (120), thereby allowing the crystalline tellurium to undergo a phase transition into amorphous tellurium oxide.

[0053] In the present invention, the UV-ozone treatment can be performed for 5 to 60 minutes, preferably for 10 to 50 minutes, and more preferably for 20 to 40 minutes. If the UV-ozone treatment time is too short, the critical point may not be reached and the phase transition may not be completed. Furthermore, even if the treatment time is increased after the critical point, there is no significant change in the performance of the thin film, so if the treatment time is too long, there is a disadvantage of being uneconomical in terms of process speed.

[0054] In the present invention, the UV-ozone treatment can be performed at 10 to 50°C, preferably 20 to 35°C, and more preferably at room temperature. If the temperature is too low, it may be difficult to proceed with the process, and if the temperature is too high, etching may occur.

[0055] In this regard, in an embodiment of the present invention, when UV-ozone treatment is performed for 30 minutes, stable amorphous tellurium oxide (a-TeO₂) exceeds the critical point. xIt was confirmed that ) was formed.

[0056] In the present invention, the amorphous tellurium oxide formed through phase transition can have superior electrical properties compared to crystalline tellurium materials. In addition, the properties of the amorphous tellurium oxide can be maintained without change even when exposed to UV-ozone treatment for a long time.

[0057] Specifically, the bandgap energy (E) of the formed amorphous tellurium oxide g ) can be 1 eV or more, preferably 2 eV or more, specifically 2 to 5 eV, for example 2.5 to 4 eV. In this regard, in an embodiment of the present invention, it was confirmed that the bandgap energy of an amorphous tellurium oxide formed through UV-ozone treatment is high at the 3 eV level.

[0058] In addition, if the formed amorphous tellurium oxide is used, 100 cm 2 It is possible to fabricate a transistor having a high field-effect mobility of / V·s or higher, and the said mobility is 200cm 2 / V·s or more, specifically 200 to 300 cm 2 It could be / V·s.

[0059] According to the present invention, an amorphous tellurium oxide can be formed through a simple process of inducing a phase transition in a crystalline tellurium material by UV-ozone treatment, and the formed amorphous tellurium oxide exhibits excellent mobility and a higher bandgap and switching ratio compared to crystalline tellurium. Therefore, the amorphous tellurium oxide formed by the present invention can be used in various electronic devices such as photovoltaic devices and memory devices, and in particular, using it allows for the fabrication of high-performance p-type field-effect transistors with excellent electrical characteristics.

[0060]

[0061] Accordingly, the present invention can also provide a field-effect transistor comprising the amorphous tellurium oxide.

[0062] A field effect transistor (FET) is a transistor that controls the current of source and drain electrodes by utilizing the principle of applying voltage to the gate electrode to create a gate through which electrons or holes flow due to the electric field of the channel. In the present invention, by introducing amorphous tellurium oxide as a semiconductor into the field effect transistor, a high-performance p-type device with excellent mobility and switching ratio can be fabricated.

[0063] In the present invention, a field-effect transistor comprising amorphous tellurium oxide has a switching ratio (I on / I off It can exhibit characteristics with a high on / off ratio. Specifically, the on / off ratio of the field-effect transistor of the present invention is 10 3 Ideally, 10 4 It may be more than 10 4 to 10 5 It could be.

[0064] In the present invention, the field-effect transistor may have a bottom-gate or top-gate structure.

[0065] A field-effect transistor according to one embodiment of the present invention may have a bottom-gate structure comprising a lower electrode, a gate insulating film formed on the lower electrode, an amorphous tellurium oxide thin film formed on the gate insulating film, and an upper electrode formed on the amorphous tellurium oxide thin film.

[0066] In describing each component of the present invention, when a component is described as being "formed on" another component, this may be interpreted to include not only the case where it is immediately above another component, but also the form in which one or more other components are included between them.

[0067] In the present invention, the lower electrode may be a gate electrode and the upper electrode may be a source / drain electrode, and the source / drain electrode has a structure in which the source electrode and the drain electrode are formed spaced apart.

[0068] In the present invention, the gate electrode is Si +++ Alternatively, metals (Au, Ag, Pt, Cu, Al, etc.) may be used. In addition, a substrate such as SiO2 may be further formed under the gate electrode.

[0069] In the present invention, the gate insulating film serves to block current flowing from the gate electrode to the source / drain electrodes and to accumulate charge at the interface with the active layer, and is made of SiO2, SiN x , SiON x Oxides or nitrides such as Al2O3, Ta2O5, TiO2, MgO, ZrO2, CeO2, K2O, Li2O, Na2O, Rb2O, Sc2O3, Y2O3, Hf2O3, CaHfO3, PbTi3, BaTa2O6, SrTiO3, AlN, etc., or insulating polymers may be used, preferably SiO2. The thickness of the gate insulating film may be 50 to 120 nm, preferably 80 to 100 nm.

[0070] After that, a crystalline tellurium material can be deposited as a semiconductor channel layer on the gate insulating film and a phase transition can be induced through the aforementioned UV-ozone treatment to form an amorphous tellurium oxide thin film. The thickness of the amorphous tellurium oxide thin film may be 5 to 50 nm, preferably 10 to 20 nm.

[0071] In the present invention, an upper electrode is formed on the amorphous tellurium oxide thin film. A channel is formed in the semiconductor layer according to the voltage applied to the upper electrode, and the current of the lower electrode is controlled.

[0072] In the present invention, one or more materials selected from the group consisting of Pt, TiN, TiAlN, TaN, Co, WN, NbN, W, and Mo may be used as the material of the upper electrode. Preferably, Pt may be used as the upper electrode, and in this case, the work function matching between the amorphous tellurium oxide and Pt is excellent, so the performance of the device can be improved.

[0073] In the present invention, the electrode can be formed through sputtering, chemical vapor deposition (CVD), plasma-enhanced chemical vapor deposition (PECVD), atomic layer deposition (ALD), plasma-enhanced atomic layer deposition (PEALD), etc.

[0074] The present invention can improve the electrical characteristics of a transistor, such as switching ratio and mobility, by using amorphous tellurium oxide as a semiconductor layer in a field-effect transistor.

[0075]

[0076] Examples

[0077]

[0078] The present invention will be explained in more detail through the following examples. However, these examples represent some experimental methods and compositions to illustrate the invention, and the scope of the invention is not limited to these examples.

[0079]

[0080] Preparation Example 1: Formation of amorphous tellurium oxide using UV-ozone treatment

[0081]

[0082] According to the process schematically shown in FIG. 3, a phase transition was induced on an 8 nm crystalline tellurium (2D Te) thin film by performing UV-ozone treatment for 30 minutes at room temperature and pressure using a mercury lamp having wavelengths of 185 nm (6.7018 eV) and 254 nm (4.8812 eV), thereby producing a 12 nm thick amorphous tellurium oxide (a-TeO₂) x A thin film was formed.

[0083] Figures 4a and 4b show transmission electron microscope (TEM) images before (a) and after (b) UV-ozone treatment, respectively, where 2D tellurium (2D Te) is a-TeO by UV-ozone treatment. x It was confirmed that it was converted, and through this, it was found that the phase transition induction reaction proceeded from the surface of the 2D Te flake inward.

[0084]

[0085] <Experimental Example 1: X-ray Photoelectron Spectroscopic Analysis of Thin Films Before and After UV-Ozone Treatment>

[0086]

[0087] To chemically quantify the materials constituting the thin films before and after UV-ozone treatment, X-ray photoelectron spectroscopy (XPS) analysis was performed on two-dimensional tellurium thin films before UV-ozone treatment and tellurium oxide thin films after treatment.

[0088] Figures 5a and 5b show XPS data before (a) and after (b) UV-ozone treatment, respectively; in the case of 2D Te, Te 3d due to natural oxidation 5 / 2 and Te 3d 3 / 2 The orbital is Te 2+ and Te 4+ The results can be confirmed by separation into two main peaks corresponding to the oxidation state, and after UV-ozone treatment, mainly Te 6+ Representing the oxidation state of a-TeO x It was possible to confirm that it had been formed.

[0089]

[0090] <Experimental Example 2: Analysis of Phase Transition State of Thin Film According to UV-Ozone Treatment Time>

[0091]

[0092] Using the method of Preparation Example 1, optical microscope and atomic force microscope images were observed on the thin film in the initial state (0 min), after 10 minutes of treatment, and after 30 minutes of treatment to confirm the phase transition state of the thin film according to the UV ozone treatment time, and the results are shown in Fig. 6. As a result of observing the microscope images, there was almost no change in the thickness of the sample during the initial 10 minutes, but after 30 minutes, the thickness increased significantly to 12 nm.

[0093] Raman spectroscopy was performed to confirm the amorphous phase transition after 30 minutes of treatment, and the results are shown in Fig. 7. After 30 minutes of UV-ozone treatment, E1-TO (94 cm -1 ), E1-LO(106cm -1 ), A1(122cm -1 ), E2(142cm -1 The intensity of characteristic Raman modes of 2D-Te, including ), is significantly reduced, and at the same time at 618 cm -1 The result showed the appearance of a new Raman peak. Accordingly, a phase transition caused by UV-ozone treatment was confirmed after 30 minutes.

[0094]

[0095] <Experimental Example 4: α-TeO x Analysis of Field-Effect Mobility of Base FET Devices

[0096]

[0097] a-TeO of Preparation Example 1 x Using P++ Si (gate) / 90nm SiO2 (gate insulating film) / 14nm α-TeO xA bottom-gate type field-effect transistor (FET) device with a (channel layer) / 50 nm Pt (source-drain electrode) structure was fabricated, and the field-effect mobility characteristics according to temperature (100 to 370 K) were verified. For comparison, a device with the same structure was fabricated using 2D Te as the channel layer, and the field-effect mobility characteristics were verified.

[0098] FIGS. 8a and 8b show an FET device using 2D Te (a) and a-TeO, respectively. x For a FET device (b) using [the element], the field-effect mobility (μ) at a temperature of 100 to 370 K eff This shows the results of measuring ).

[0099] Measurement results showed that both devices exhibited a charge transport mechanism dominated by thermionic emission (TE) at room temperature, and a transition to a charge transport mechanism dominated by tunneling was observed as the temperature decreased to 100K. In particular, in the high electric field region at the 100K level, a-TeO x It was confirmed that the FET device using [material] had a field-effect mobility approximately twice as high as the FET device using 2D Te, and the switching ratio also increased.

[0100]

[0101] <Experimental Example 5: α-TeO x Analysis of Electrical Characteristics of Base FET Devices

[0102]

[0103] 2D Te and a-TeO of Preparation Example 1 x For a field-effect transistor (FET) device fabricated using [the method], the Schottky barrier height (SBH) and contact resistance were measured.

[0104] Figures 9 and 10 show 2D Te or α-TeO, respectively. xThis graph shows the SBH and contact resistance measurement results according to gate voltage in an FET device to which α-TeO is applied. As a result of the analysis, despite the use of metal, α-TeO x It was confirmed that the SBH of the FET device is at the 10 meV level, which is approximately 7 times lower than that of the 2D-Te FET device, and that the Fermi level locking phenomenon is almost alleviated, and compared to the 2D-Te FET device, a-TeO x It was confirmed that the contact resistance of the FET device is extremely low.

[0105] FIG. 11 shows a 2D Te-based FET device and a-TeO x I of the based FET device ds -V gs This shows a graph and an on / off state band diagram explaining it (Top: Pt-Te-Pt, Bottom: Pt-TeO x -Pt) is schematically shown in Fig. 12. Referring to this, α-TeO x In the case of the base FET device, it can be seen that the switching ratio of the on / off state is excellent because the large bandgap and work function difference hinder electron flow.

[0106] Based on the above experimental results, it was found that the problem of 2D Te-based devices with a low switching ratio can be solved by inducing a phase transition through UV-ozone treatment using the present invention.

[0107]

[0108] <Experimental Example 6: Analysis of Electrical Properties of Tellurium Oxide According to Manufacturing Method>

[0109]

[0110] For crystalline tellurium and tellurium oxides prepared by various methods, thickness (nm) and electric field mobility (cm²) 2 The values ​​for / V·s), flashing ratio, and band gap (eV) are shown in Table 1 below.

[0111]

[0112] Sample Type Crystal System Formation Method Thickness Mobility Flashing Ratio Band Gap 1Te Hexagonal Sputtering 45 2.5 9.3×10^3 0.9 42TeO x Orthorhombic reactive sputtering (PO 7%) 43.6 1.8 2.7 3TeO x Se-alloyed amorphous TeO x and thermal evaporation with Se powder 1515~10^7 1.14α-TeO x Tetragonal series evaporation 53.83.3×10^3-5TeO x UV-Ozone treatment of amorphous 2D Te 12~250~10^53

[0113] Experimental results showed that when tellurium oxide was formed by inducing a phase transition through UV-ozone treatment according to the present invention, the crystal system was amorphous, and it exhibited characteristics of high mobility, switching ratio, and band gap compared to crystalline tellurium. On the other hand, when other methods were used, the process was complex, or one or more of the properties of mobility, switching ratio, and band gap of the manufactured tellurium oxide were significantly degraded.

[0114] Accordingly, it was found that by using the present invention, the low bandgap and switching ratio characteristics of tellurium can be overcome in a simple way to form tellurium oxide with excellent physical properties.

[0115]

[0116] The present invention is not limited by the embodiments described above and the attached drawings, but is intended to be limited by the appended claims. Accordingly, various substitutions, modifications, and changes may be made by those skilled in the art within the scope of the technical concept of the present invention as described in the claims, and such are also to be considered to fall within the scope of the present invention.

Claims

1. A method for forming amorphous tellurium oxide by inducing a phase transition through a UV-Ozone (UV-O3) treatment step in which ultraviolet (UV) rays are irradiated onto a crystalline tellurium material to generate ozone (O3).

2. In Paragraph 1, A method for forming amorphous tellurium oxide, wherein the above-mentioned ultraviolet-ozone treatment step is performed by irradiating with a light source including a wavelength range of 100 to 300 nm.

3. In Paragraph 2, A method for forming amorphous tellurium oxide, wherein the light source comprises a wavelength range of 100 to 200 nm and a wavelength range of 220 to 300 nm.

4. In Paragraph 1, The phase transition through the above UV-ozone treatment step, A step in which oxygen molecules (O2) are decomposed into oxygen atoms (O) by light source energy including a wavelength range of 100 to 200 nm; A step in which the above oxygen atom (O) combines with an oxygen molecule (O2) to form ozone (O3); By light source energy including a wavelength range of 220 to 300 nm, the ozone (O3) is converted into oxygen molecules (O2) and oxygen radicals (O * Step of being decomposed into ); and The above oxygen radical (O * A step in which tellurium ionized by a light source reacts to form tellurium oxide. A method for forming amorphous tellurium oxide, performed through 5. In Paragraph 1, The above UV-ozone treatment step, A method for forming amorphous tellurium oxide, performed using an ultraviolet ozone generator comprising a power supply, a low-pressure mercury vapor discharge lamp, a sample tray, and a sealed chamber.

6. In Paragraph 1, A method for forming amorphous tellurium oxide, wherein the above-described UV-ozone treatment step is performed for 5 to 60 minutes.

7. In Paragraph 1, Bandgap energy (E) of the formed amorphous tellurium oxide g A method for forming amorphous tellurium oxide in which ) is 1 eV or more.

8. In Paragraph 1, The mobility of the formed amorphous tellurium oxide is 100 cm⁻¹ 2 A method for forming amorphous tellurium oxide with / V·s or higher.

9. Amorphous tellurium oxide formed by the method of any one of claims 1 to 8.

10. A field-effect transistor comprising the amorphous tellurium oxide of claim 9.

11. In Paragraph 10, The above field-effect transistor, lower electrode, A gate insulating film formed on the lower electrode above, An amorphous tellurium oxide thin film formed on the gate insulating film, and Upper electrode formed on the above amorphous tellurium oxide thin film A field-effect transistor including 12. In Paragraph 10, The on / off ratio of the above field-effect transistor is 10 3 Lee Sang-in, field-effect transistor.

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