TWI664304B - Indium gallium zinc oxide / copper chromium / indium gallium zinc oxide transparent conductive film - Google Patents

Abstract

The present invention is to provide a transparent conductive film of indium gallium zinc oxide / copper chromium / indium gallium zinc oxide, which mainly deposits a target material on a substrate. The substrate is a flexible plastic and is provided with a first indium gallium zinc oxide. (IGZO) layer is sputter deposited on the substrate for 5 minutes; a second copper-chromium (Cu: Cr) layer is sputter deposited on the first indium gallium zinc oxide (IGZO) layer for 30 seconds, the second copper The copper (Cr) ratio of the chromium (Cu: Cr) layer is copper (Cu): chromium (Cr) = 70:30; the third indium gallium zinc oxide (IGZO) layer is sputter deposited on the second copper chromium (Cu) : Cr) layer for 5 minutes; in this way, it has a sheet resistance of 231Ω / o, a light transmittance of 74.67%, a resistivity of 1.19 x 10 ^-3 Ω-cm, and a photoelectric index of 2.4 x 10 ^-4 Ω ^-1 , which can achieve the best corrosion resistance. Resistance, conductivity and light transmission, and has a flexible and smooth surface to prevent cracking.

Description

Indium gallium zinc oxide / copper chromium / indium gallium zinc oxide transparent conductive film

The invention relates to a transparent conductive film of indium gallium zinc oxide / copper chromium / indium gallium zinc oxide, in particular, a target is sputter-deposited on a substrate. The substrate is a soft plastic and is provided with a first indium gallium zinc oxide. (IGZO) layer is sputter deposited on the substrate for 5 minutes; a second copper chromium (Cu: Cr) layer is sputter deposited on the first indium gallium zinc oxide (IGZO) layer for 30 seconds, the second copper The copper-chromium ratio of the chromium (Cu: Cr) layer is copper (Cu): chromium (Cr) = 70:30; the third indium gallium zinc oxide (IGZO) layer is sputter deposited on the second copper chromium (Cu) : Cr) layer for 5 minutes; in this way, it has a sheet resistance of 231Ω / □, a light transmittance of 74.67%, a resistivity of 1.19 x 10 ^-3 Ω-cm, and a photoelectric index of 2.4 x 10 ^-4 Ω ^-1 , which can achieve the best corrosion resistance. Resistance, conductivity and light transmission, and has a flexible and smooth surface to prevent cracking.

According to the original, transparent conductive films were mainly used in windshields of aircrafts. With the rapid development of semiconductor technology, in order to provide consumers with demand for lightness, thinness, shortness and visual beauty, transparent conductive films are also widely used, such as flat surfaces. Indium tin oxide transparent conductive film (ITO) applied to the display, although the resistance value and light transmittance of the indium tin oxide transparent conductive film (ITO) have reached the optimal state, However, its performance at high temperatures is not stable, and its target is extremely expensive and toxic. When an oxide transparent conductive film is used, its resistivity can reach 10 due to its high light transmittance in the visible light region (400 ~ 800nm). ^-4 Ω-cm, but its transmittance and conductivity in the photoelectric properties are greatly affected by the content and type of dopants. Generally common transparent conductive films are indium oxide doped tin (In ₂ O ₃ : Sn , ITO), zinc oxide doped aluminum (ZnO: Al, AZO), zinc oxide doped gallium (ZnO: Ga, GZO), the doped ions must match the ionic radius of the substituted metal ion, otherwise it will cause the lattice Twisted, making the film less crystalline In order to meet the need for a very smooth and smooth surface for future transparent conductive films, the addition of various dopants has gradually developed and applied amorphous semiconductor materials; the resistivity of general transparent conductive films (TCO) is about 10 ^-3 ~ 2 × 10 ^-4 Ω-cm, if the resistivity can be lowered, the series resistance can be reduced, and the electron transmission efficiency can be increased. In addition, the flexibility of the thin film in the transparent electrode is also important. Generally, the rigidity of the ceramic oxide is high. It is not easy to bend, so there is no problem in the application of film formation on glass, but if it is applied to flexible substrates, the film thickness should not be too thick, otherwise it is easy to crack in bending; and metal thin films (such as: gold, silver, copper (Such as thin film) has excellent conductivity, but its light transmittance is poor. If you want to increase the transmittance in the visible light range, the thickness of the film must be less than 100Å. However, when the thickness of most metal thin films is less than 100Å, it will form an island shape. The continuous film increases the resistance of the film. When the island structure becomes larger, the diffraction effect will occur and the visible light transmittance will decrease; therefore, the inventors have known that the existing Deletions, is painstaking research, modified, then the present invention is first invention.

The main purpose of the present invention is to achieve the best corrosion resistance, electrical conductivity, and light transmission, transparent surface with indium gallium zinc oxide / copper chromium / indium gallium zinc oxide that has flexibility and a smooth surface that prevents cracking. film.

The main features of the present invention are: the first indium gallium zinc oxide (IGZO) layer is deposited on the substrate by radio frequency (RF) magnetron sputtering, the sputtering deposition time is 5 minutes, and the sputtering power is 125 watts; A copper-chromium (Cu: Cr) layer is a direct current (DC) magnetron sputtering deposited on the first indium gallium zinc oxide (IGZO) layer. The sputtering deposition time is 30 seconds. The second copper-chrome (Cu: Cr) The copper-chromium ratio of the) layer is copper (Cu): chromium (Cr) = 70: 30, sputtering power is 110 watts; third oxygen An indium gallium zinc (IGZO) layer is deposited on the second copper chromium (Cu: Cr) layer by radio frequency (RF) magnetron sputtering. The sputtering deposition time is 5 minutes and the sputtering power is 125 watts.

The indium gallium zinc oxide / copper chromium / indium gallium zinc oxide transparent conductive film of the present invention, wherein the target material is composed of an indium gallium zinc oxide (IGZO) ceramic target, a chromium (Cr) metal target, and a copper (Cu) sheet. Alloy target, which uses vacuum co-sputtering technology to form a copper chromium (Cu: Cr) alloy.

The transparent conductive film of indium gallium zinc oxide / copper chromium / indium gallium zinc oxide according to the present invention, wherein the sputtering system of the target material deposited on the substrate is argon (Ar), oxygen (O ₂ ), and nitrogen ( N ₂ ).

The transparent conductive film of indium gallium zinc oxide / copper chromium / indium gallium zinc oxide according to the present invention, wherein the substrate is a soft plastic, has a sheet resistance of 231Ω / □, a light transmittance of 74.67%, and a resistivity of 1.19 x 10 ^-3 Ω- cm, photoelectric index 2.4 x 10 ^-4 Ω ^-1 .

1‧‧‧ substrate

2‧‧‧ transparent conductive film

20‧‧‧ First Indium Gallium Zinc Oxide (IGZO) Layer

21‧‧‧Second copper-chromium (Cu: Cr) layer

22‧‧‧ Third Indium Gallium Zinc Oxide (IGZO) Layer

The first figure is a schematic diagram of a transparent conductive film on a substrate according to an embodiment of the present invention.

The second figure shows an XRD diffraction pattern of different DC powers according to an embodiment of the present invention.

The third figure shows XRD diffraction patterns of different alloy ratios in the embodiment of the present invention.

The fourth figure shows a characteristic curve of light transmittance versus incident light wavelength according to an embodiment of the present invention.

The fifth figure shows the surface topography (a) of the embodiment of the present invention.

The sixth figure is a surface topography diagram (2) of the embodiment of the present invention.

Regarding the technical purpose of the present invention in order to achieve the above-mentioned purposes and effects, The paragraphs, here are the preferred and feasible embodiments, and are shown in the drawings, as follows:

In the embodiment of the present invention, please refer to the first figure, which mainly deposits the target material on the substrate 1, and the substrate 1 is rotated during the sputtering process, so that the film has sufficient time for heat transfer and improves the The uniformity of the film, the film is a transparent conductive film 2, which is provided with a first indium gallium zinc oxide (IGZO) layer 20 (indium gallium zinc oxide film), and a second copper chromium (Cu: Cr) Layer 21 (copper chromium thin film) and third indium gallium zinc oxide (IGZO) layer 22 (indium gallium zinc oxide thin film). The sputtering system of the target material deposited on the substrate 1 is argon (Ar). Oxygen (O ₂ ) and Nitrogen (N ₂ ), wherein the first indium gallium zinc oxide (IGZO) layer 20 is a radio frequency (RF) magnetron sputtering deposited on the substrate 1. The sputtering deposition time is 5 minutes. The plating power is 125 watts. The first indium gallium zinc oxide (IGZO) layer 20 is useful for sputter deposition of the second copper chromium (Cu: Cr) layer 21; the second copper chromium (Cu: Cr) layer 21 Direct current (DC) magnetron sputtering is deposited on the first indium gallium zinc oxide (IGZO) layer 20, the sputtering deposition time is 30 seconds, and the copper-zirconium ratio of the second copper-chromium (Cu: Cr) layer 21 The system is copper (Cu): chromium (Cr) = 70: 30, The sputtering power is 110 watts; the third indium gallium zinc oxide (IGZO) layer 22 is a radio frequency (RF) magnetron sputtering deposited on the second copper chromium (Cu: Cr) layer 21, and the sputtering deposition time is 5 Minutes, the sputtering power is 125 watts. The third indium gallium zinc oxide (IGZO) layer 22 helps the second copper chromium (Cu: Cr) layer 21 to avoid oxidation; thus, the target material is indium gallium oxide. An alloy target composed of a zinc (IGZO) ceramic target, a chromium (Cr) metal target, and a copper (Cu) sheet. The alloy target uses a vacuum co-sputtering technique to form a copper-chromium (Cu: Cr) alloy; The indium gallium zinc oxide (IGZO) layer 20 and the third indium gallium zinc oxide (IGZO) layer 22 are amorphous materials and have relatively smooth surfaces. The second copper chromium (Cu: Cr) layer 21 is It is an intermediate metal layer, which can reduce the resistivity of the transparent conductive film 2, enhance flexibility and prevent cracking. This metal layer contains copper (Cu) with low resistivity and is added with chromium (Cr). Improves the corrosion resistance of the metal layer.

The multi-gun co-sputtering vacuum equipment used in the present invention mainly includes a vacuum cavity, a gas control system, a vacuum pumping system, a vacuum gauge, and a power supply. The vacuum cavity system has three sets of sputtering targets. Material position, rotatable base plate, two sets of tungsten lamp heaters, one set of rotary gears; the gas control system has three sets of mass flow controllers (MFC) to control the gas (argon, oxygen and nitrogen) Flow; the vacuum pump system includes oil mechanical pump (ALCATEL 2012A) and high vacuum oil diffusion pump; the vacuum gauge uses a thermocouple vacuum gauge, when the pressure is in a high vacuum, a hot cathode ion vacuum gauge is used The power supply is two sets of high-frequency radio frequency (RF) power supplies and the other is a direct current (DC) power supply; when sputtering, the vacuum chamber is first powered by the oil-type machinery of the vacuum pump system Pump (ALCATEL 2012A) to rough vacuum, and then use the high vacuum oil diffusion pump of the vacuum pump system to high vacuum to improve the quality of thin film and hydrogen plasma treatment. spectrum The instrument (Hitachi Ultraviolet-Visible 2008A Spectrophotometer) measures the average light transmittance (Avg. Transmittance) of the transparent conductive film 2 and the photoelectric index (Figure of merit, FOM), such as the formula: The Four-Point Probe can measure the sheet resistance of the transparent conductive film 2 and the Surface Profiler (α-step) can measure the thickness of the transparent conductive film 2 ), X-ray diffraction analysis (XRD) can be used as a non-destructive analysis technology to detect the characteristics of crystalline materials, and scanning electron microscope (SEM) can provide high resolution and long depth of field on the sample surface and near surface. image.

The invention uses the magnetron sputtering method to grow a thin film, and has the characteristics of continuous production of high-quality films. Its process temperature is lower than other technologies, and it conforms to the low-temperature process required for the substrate 1 to be a soft plastic. Therefore, a magnetron is used. The purpose is to increase the deposition rate of the coating. During the sputtering process, the substrate 1 is rotated to increase the sputtering work time, allowing the film to have sufficient time to dissipate heat during sputtering, although it will cause the sputtering time. It is slower than direct sputtering, but it makes the film more uniform to improve the adhesion between the film and the substrate 1. It is mainly added with bias voltage and argon and oxygen to achieve plasma surface modification and make the substrate 1 The hydrophobicity of the surface is changed to hydrophilic to increase the adhesion of the film, and then the film is grown by magnetron sputtering and placed in the cavity to maintain a negative pressure of about 2 × 10 ^-2 (PA) or less. (Cu: Cr) was used as a target, and a copper-chromium alloy film was formed by sputtering.

The XRD diffraction patterns of the first indium gallium zinc oxide (IGZO) layer 20 or the third indium gallium zinc oxide (IGZO) layer 22 of the present invention at different DC powers of the substrate 1 are shown in the second figure. The axis system is Diffraction Angle (degree) and the longitudinal axis system is intensity (au). When the first indium gallium zinc oxide (IGZO) layer 20 or the third indium gallium zinc oxide is sputtered at room temperature, (IGZO) layer 22, its deposition time is fixed for 20 minutes. Under different DC power (20W, 40W, 60W, 80W, 90W) deposition, the film does not have any crystal orientation, so it can be judged that the first indium oxide The gallium zinc (IGZO) layer 20 and the third indium gallium zinc oxide (IGZO) layer 22 do not generate a crystalline phase, and both exist in an amorphous structure. An amorphous thin film is optimal for the substrate 1 of an amorphous plastic. Of adhesion.

XRD of different alloy ratios of the first indium gallium zinc oxide (IGZO) layer 20, the second copper chromium (Cu: Cr) layer 21, and the third indium gallium zinc oxide (IGZO) layer 22 on the substrate 1 according to the present invention The diffraction pattern is shown in the third figure. The horizontal axis is the diffraction angle (Diffraction Angle (degree)) and the vertical axis is the intensity (lntensity (au)). When the first indium gallium zinc oxide (IGZO) is fixed The deposition thickness of the layer 20 and the third indium gallium zinc oxide (IGZO) layer 22 is that the sputtering deposition time is 5 minutes, the sputtering power is 125 watts, and the copper-chromium of the second copper-chromium (Cu: Cr) layer 21 The ratio is copper (Cu): chromium (Cr) = 90: 10, copper (Cu): chromium (Cr) = 80: 20, copper (Cu): chromium (Cr) = 70: 30, and the sputtering deposition time is For 30 seconds, the sputtering power was 110 watts, and no significant diffraction peak signal appeared, which still mainly existed in an amorphous structure. This result is the same as that of the single layer of the first indium gallium zinc oxide (IGZO) layer 20 or the first The indium gallium zinc oxide (IGZO) layer 22 is the same. It can be seen that the metal film layer of the second copper chromium (Cu: Cr) layer 21 also has an amorphous structure. When the copper of the second copper chromium (Cu: Cr) layer 21 is copper The chromium ratio is copper (Cu): chromium (Cr) = 70: 30, change the thickness of the metal layer, and sputter plating Product is 20 seconds, a sheet resistance of 1.9KΩ / □, the light transmittance of 76.04%, the resistivity of 5.8 x 10 ^-2 Ω-cm, the photo index 7.5 x 10 ^-6 Ω ^-1, sputter deposition time of 30 seconds Clock, with sheet resistance of 231Ω / □, light transmittance of 74.67%, resistivity of 1.19x10 ^-3 Ω-cm, photoelectric index of 2.4 x 10 ^-4 Ω ^-1 , so with this second copper-chromium (Cu: Cr) layer The 21 metal layer process time decreases, and the resistivity increases accordingly. That is, when the thickness of the 21 copper layer of the second copper chromium (Cu: Cr) layer increases, the sheet resistance decreases accordingly.

Characteristics of the transmittance of the first indium gallium zinc oxide (IGZO) layer 20, the second copper chromium (Cu: Cr) layer 21, and the third indium gallium zinc oxide (IGZO) layer 22 to the wavelength of incident light according to the present invention For the graph, please refer to the fourth figure. The horizontal axis is the wavelength (Wavelength (nm)), and the vertical axis is the transmittance (%). When the second copper chromium (Cu: Cr) layer is changed 21 deposition time (10sec, 20sec, 30sec), it is known that the transmittance of the characteristic curve is more than 75%, but as the process time increases, the transmittance will decrease.

For the surface morphology of the first indium gallium zinc oxide (IGZO) layer 20, the second copper chromium (Cu: Cr) layer 21, and the third indium gallium zinc oxide (IGZO) layer 22 of the present invention, please refer to the fifth figure. As shown in the figure, the copper-zirconium ratio of the second copper-chromium (Cu: Cr) layer 21 is copper (Cu): chromium (Cr) = 70: 30, which was observed under a low magnification (500 times) and was not found. Any crack can not only improve the conductivity and FOM value, but also effectively prevent cracking.

The first indium gallium zinc oxide (IGZO) layer 20 or the third indium gallium oxide according to the present invention The surface morphology of the zinc (IGZO) layer 22 at a thickness of 100 nm, please refer to the sixth figure, which is observed under a low magnification (500 times), the surface is smooth and no cracks are found, mainly due to the first The indium gallium zinc oxide (IGZO) layer 20 or the third indium gallium zinc oxide (IGZO) layer 22 has an amorphous thin film characteristic.

The photoelectric characteristics of the transparent conductive film of the present invention can be evaluated by a photoelectric index (Figure of merit, FOM) factor. , Where T is the light transmittance, R _s is the sheet resistance, that is, R _s = 1 / σt, σ is the conductivity, and t is the film thickness. Generally, the thicker the film thickness, the lower the sheet resistance, but sacrifices the transmission Optical property; therefore, there needs to be a balance between sheet resistance and light transmittance. Through evaluation of the figure of merit (FOM) factor, a transparent conductive film with good conductivity and light transmittance can be obtained. (Cu) and chromium (Cr) use vacuum co-sputtering technology to form a copper-chromium alloy. The copper-chromium alloy can greatly improve the corrosion resistance of copper (Cu). Using a metal layer as an intermediate interlayer, the A ductile metal is used as an intermediate layer of a transparent conductive material, which not only increases conductivity but also ductility, and the substrate 1 of soft plastic is not only lightweight, high in toughness and impact resistance, but also can be made into a flexible electron. Components, commonly used plastic materials are polycarbonate (PC), polyethylene terephthalate (PET), polyethylene naphthalate (PEN), polyimide (PI), polymethyl methacrylate (PMMA), etc., and the present invention mainly uses polycarbonate (PC) as the substrate 1, because the polycarbonate (PC) is transparent Good in performance and easy to obtain; therefore, the first indium gallium zinc oxide (IGZO) layer 20, the second copper chromium (Cu: Cr) layer 21 and the third indium gallium zinc oxide (IGZO) layer 22 of the present invention are formed. The transparent conductive film 2 has a sheet resistance of 231Ω / □, a light transmittance of 74.67%, a resistivity of 1.19 x 10 ^-3 Ω-cm, and a photoelectric index of 2.4 x 10 ^-4 Ω ^-1 , which can achieve the best corrosion resistance. Resistance, conductivity and light transmission, and has a flexible and smooth surface to prevent cracking.

In summary, the embodiments of the present invention have indeed achieved the intended purpose and use. Efficacy, and it is not known that the same structural features are publicly known and common antecedent. Therefore, the present invention should be able to meet the application requirements of the invention patent, apply according to the law, and ask for an early review.

Claims (4)

A transparent conductive film of indium gallium zinc oxide / copper chromium / indium gallium zinc oxide is mainly deposited on a substrate by sputtering, and the substrate is rotated in the sputtering process, so that the film has sufficient time for heat transfer and improves The uniformity of the thin film is characterized by: the first indium gallium zinc oxide (IGZO) layer is deposited on the substrate by radio frequency (RF) magnetron sputtering, the sputtering deposition time is 5 minutes, and the sputtering power is 125 watts; Two copper-chromium (Cu: Cr) layers are deposited by direct current (DC) magnetron sputtering on the first indium gallium zinc oxide (IGZO) layer. The sputtering deposition time is 30 seconds, and the second copper-chrome (Cu: The copper-chromium ratio of the Cr) layer is copper (Cu): chromium (Cr) = 70: 30, and the sputtering power is 110 watts; the third indium gallium zinc oxide (IGZO) layer is a radio frequency (RF) magnetron sputtering Deposited on the second copper chromium (Cu: Cr) layer, the sputtering deposition time is 5 minutes, and the sputtering power is 125 watts. The transparent conductive film of indium gallium zinc oxide / copper chromium / indium gallium zinc oxide as described in item 1 of the scope of patent application, wherein the target material is an indium gallium zinc oxide (IGZO) ceramic target, a chromium (Cr) metal target An alloy target composed of copper and copper (Cu) flakes. The alloy target uses a vacuum co-sputtering technique to form a copper-chromium (Cu: Cr) alloy. According to the transparent conductive thin film of indium gallium zinc oxide / copper chromium / indium gallium zinc oxide described in item 1 of the scope of application for patent, wherein the sputtering system of the target material deposited on the substrate is argon (Ar), Oxygen (O ₂ ) and nitrogen (N ₂ ). The transparent conductive film of indium gallium zinc oxide / copper chromium / indium gallium zinc oxide described in item 1 of the scope of application for patent, wherein the substrate is a soft plastic, and the transparent conductive film formed on the substrate has a sheet resistance of 231Ω / □, the light transmittance is 74.67%, the resistivity is 1.19 x 10 ^-3 Ω-cm, and the photoelectric index is 2.4 x 10 ^-4 Ω ^-1 .