TWI476291B - Preparation method of spinel nickel cobalt oxide target - Google Patents

Description

Method for producing spinel nickel cobalt oxide target

The present invention relates to a method for producing a target, and more particularly to a method for producing a spinel nickel-cobalt oxide target.

The transparent conductive oxide (TCO) is defined as a film having a light transmittance of 80% or more in the visible light range and a high electrical conductivity, and a film having a resistance value of less than 10 ^-3 Ω-cm. It can be called a transparent conductive film. The materials of the transparent conductive film are mainly classified into two types: one is a metal film, and the other is a metal oxide semiconductor film. The metal film was used as a transparent electrode in the early stage. Although it has excellent conductivity, the absorption rate of light by the metal film is too high, resulting in a decrease in transmittance. If the transmittance in the visible range is to be increased, the film thickness cannot be too thick. (<100A), however, when the thickness of the metal film is less than 100A, an island-like discontinuous film is formed, which causes an increase in the resistance value of the film and a poor stability of the metal film, and the metal film is gradually eliminated. Metal oxide semiconductor thin films have gradually replaced metal thin films because of their good visible light transmittance and the electrical conductivity close to metal thin films. Therefore, in recent years, a large number of research personnel have been investigating TCO.
Since the conduction carrier of the N-type transparent conductive film is mainly electrons and the mobility of the electron itself is high, the conductivity of the N-type transparent conductive film is good, and the light transmittance of the N-type transparent TCO is high. The P-type TCO was developed in recent years. The transparent conductive oxide material has a band gap of about 3 eV or more, and the energy in the visible range (≒1.6~3.3 eV), so it is not enough to valence the TCO. Band) Electron excitation to the conduction band. Only light with a wavelength between 400 and 800 nm can penetrate without generating light absorption, so the TCO is transparent in the visible range. When the incident light energy is greater than the energy gap, the electrons of the valence band are excited to the conduction band, so the boundary of the light transmission range at the short wavelength (the energy gap wavelength, λg) is determined by the size of the energy gap.
The carriers in the TCO are in a plasma state and interact with light very strongly. When the wavelength of the incident light is greater than the wavelength determined by the plasma frequency (plasma wavelength, λp), the incident light is reflected. For the TCO, the plasma wavelength is in the infrared region, so the light transmission range is at the long wavelength. The limits are determined by the frequency of the plasma. The decrease in film transparency is mostly caused by absorption and reflection. There are many reasons for absorption and reflection, in addition to the above-mentioned energy level absorption and free carrier absorption and reflection, as well as impurities, defects and lattice oscillations. The absorption, the degree of crystallization of the film, and the diffusion caused by the surface roughness all affect the performance of transparency.
Materials of several P-type TCOs such as NiCo ₂ O ₄ , Cu ₂ O, NiO, CuGaO ₂ and the like are known. NiCo ₂ O ₄ has better infrared light transmittance in the infrared region than other P-type transparent conductive oxides. If the performance of the P-type TCO oxide transparent electrode can be effectively improved, it can form a PN junction with the N-type TCO, which can be applied to many fields, for example, transparent electronic components, and the P-type conductive film of the OLED hole injection layer is high. The work function can reduce the energy barrier of hole injection and the application of solar cell fabrication. For example, a NiO transparent conductive film is used in a light-emitting diode as a hole transmission and electrochromic element and a solar photovoltaic element. NiCo ₂ O _{4 is} known to have high penetration of infrared light, and because the infrared light area accounts for nearly half of the solar energy, it can effectively improve the infrared light absorption of solar cells, if it is applied to full-band solar energy. The battery can further absorb the infrared light band to improve the conversion efficiency and effectively increase the utilization of solar energy.
Due to the surface diffusion and evaporation condensation characteristics of spinel nickel-cobalt oxide during high-temperature bulk sintering, it is difficult to densify, resulting in porous, loose and low strength of the sintered body. The structure is quite difficult to make a sputter target, so there are many methods for improving the compactness of the spinel nickel-cobalt oxide target, such as hot isostatic pressing or very fine The nano-powder combined with high-pressure imprinting can achieve the effect of increasing density. However, in practical applications, the addition of a sintering aid to promote high temperature diffusion is still the most convenient and effective method. The addition of alkali metal ions in the invention can effectively increase the vacancy of oxygen ions and thereby help the oxygen diffusion in the oxide, and increase the driving force of sintering to effectively increase the density. . Among them, the effect of adding alkali metal ions is the most attractive, and a small amount of addition (2 wt%) can form a densification of a relative density of 90% or more for a spinel nickel-cobalt oxide target. effect.

SUMMARY OF THE INVENTION A primary object of the present invention is to provide a method of producing a spinel nickel-cobalt oxide target by increasing the density of a spinel nickel-cobalt oxide target by the addition of an alkali metal ion.
In order to achieve the above object, the present invention discloses a method for producing a spinel nickel-cobalt oxide target by adding a spinel nickel-cobalt oxide to a powder containing an alkali metal ion (eg, lithium hydroxide or hydroxide). Sodium), after calcination, repeated grinding and sieving, followed by dry pressing molding, pressing the mixed powder into a circular molded body, and placing the molded body in a high temperature furnace for high-temperature sintering (about At 1500 ° C), a highly densified NiCo ₂ O ₄ target having a relative density of 90% or more is obtained.

In order to provide a better understanding and understanding of the features of the present invention and the efficacies achieved, the preferred embodiments and detailed descriptions are provided as follows:
The present invention is to improve the disadvantage that the conventional spinel nickel-cobalt oxide material is not easily sintered and dense, and the highly densified spinel nickel-cobalt oxide target can be obtained by adding the alkali metal ion-containing powder.
First, please refer to the first drawing, which is a manufacturing flow chart of a preferred embodiment of the present invention; as shown, the present invention discloses a method for manufacturing a spinel nickel-cobalt oxide target, the manufacturing method The system consists of the following steps:
Step S10, mixing a spinel nickel cobalt oxide powder with a powder containing an alkali metal ion to form a mixed powder;
Step S20, mixing the mixed powder with a solvent to form a mixed powder slurry, and grinding the mixed powder slurry;
In step S30, the mixed powder slurry is dried, heated and repeatedly sieved to form a target powder; and in step S40, the target powder is pressed into a molded body and sintered to form a spinel nickel cobalt oxide. Target.
In step S10, the alkali metal ion-containing powder is selected from sodium hydroxide or lithium hydroxide.
In step S20, the solvent is selected from one of the group consisting of deionized water and alcohol.
In step S30, the heating temperature is 700 °C.
In step S40, the sintering temperature is 1000 °C.
The invention adopts a spinel nickel-cobalt oxide ceramic target with lithium hydroxide or sodium hydroxide to make the relative density thereof more than 90%, so as to improve the defect that the spinel nickel-cobalt oxide material is not easily sintered and compacted, and A highly densified spinel nickel-cobalt oxide target can be added by an appropriate ratio of lithium hydroxide or sodium hydroxide.
Please refer to the second figure, which is a diagram showing the relationship between the alkali metal ion addition ratio and the target density and the relative density of the target according to a preferred embodiment of the present invention; as shown in the figure, the alkali metal ion powder disclosed in the present invention is shown. In this embodiment, sodium ion is used as a description. When the amount of sodium hydroxide added is 2 wt%, the relative density of the sodium hydroxide-doped nickel-cobalt oxide target is increased from 78% to 94%, as opposed to The relative density (78%) of the target without sodium hydroxide is added, the relative density of the target is greatly increased, and the strength of the target is also increased, that is, the addition of sodium hydroxide to the spinel nickel-cobalt oxide target Helping the sintering of the spinel nickel-cobalt oxide target, the target densification is also increased, and the relative density of the target is also greatly increased, that is, the life of the target is increased, and the time for the target replacement can be reduced in the industry. cost. Therefore, the addition of the alkali metal ion powder not only enhances the compactness of the spinel nickel-cobalt oxide target, but also improves the life and strength of the target.
Furthermore, please refer to the third drawing, which is a micrograph of the surface type of the highly densified spinel nickel-cobalt oxide target according to a preferred embodiment of the present invention; as shown, the present invention The high-density spinel-nickel-cobalt oxide target containing alkali metal ions is sintered at a high temperature (about 1500 ° C), and the spinel nickel-cobalt oxide is circularly molded to form spinel nickel-cobalt The oxide dense ceramic circular target, under high temperature heat treatment, promotes the sintering of the added alkali metal ions without causing deformation, cracks or pores of the spinel nickel-cobalt oxide target, and still forms a circular target shape. This application of the target is beneficial. The surface microstructure of the target shows that the microstructure of the target surface is quite dense, and there are only some micro-closed pores, but it does not affect the compactness of the target. Therefore, the relative density of the target is 94%, which can be used as a practical application. Commercial target.
In summary, the method for producing a spinel nickel-cobalt oxide target of the present invention is characterized in that "the spinel nickel-cobalt oxide is added with an alkali metal ion sintering accelerator" as a main strategy, and the spinel nickel can be effectively improved. The cobalt oxide target material itself has the disadvantages of being difficult to be sintered and dense, and has the advantages of densification, improvement of target strength, reduction of cost of target loss, etc., but the above is only a preferred embodiment of the present invention. The present invention is not intended to limit the scope of the present invention, and the equivalents and modifications of the shapes, structures, features and spirits of the present invention should be included in the scope of the present invention.
The invention is a novelty, progressive and available for industrial use, and should meet the requirements of the patent application stipulated in the Patent Law of China, and the invention patent application is filed according to law, and the prayer bureau will grant the patent as soon as possible. prayer.

No

First: it is a manufacturing flow chart of a preferred embodiment of the present invention;
2 is a diagram showing a relationship between an alkali metal ion addition ratio and a target density and a target relative density according to a preferred embodiment of the present invention; and a third diagram: it is a preferred embodiment of the present invention. Photomicrograph of a surface morphology of a highly densified spinel nickel-cobalt oxide target.

Claims (6)

A method for producing a spinel nickel-cobalt oxide target, comprising the steps of:
Mixing a spinel nickel-cobalt oxide powder with a powder containing an alkali metal ion to form a mixed powder;
Mixing the mixed powder with a solvent to form a mixed powder slurry, and grinding the mixed powder slurry;
The mixed powder slurry is dried, heated and sieved to form a target powder; and the target powder is pressed into a molded body and sintered to form a spinel nickel cobalt oxide target. The manufacturing method according to claim 1, wherein the alkali metal ion-containing powder is selected from the group consisting of sodium hydroxide and lithium hydroxide or any combination of the above. The manufacturing method according to claim 1, wherein the solvent is selected from the group consisting of deionized water and alcohol. The manufacturing method according to claim 1, wherein in the heating step, the heating temperature is 700 °C. The manufacturing method according to claim 1, wherein in the sintering step, the sintering temperature is 1000 °C. The manufacturing method according to claim 1, wherein the spinel nickel-cobalt oxide target has a relative density of 90% or more.