A Study of Lithium Silicon Oxynitride (LiSiON) Deposited By RF Sputtering for All-Solid-State Thin Film Batteries

At present, we suffer from various environmental issues such as air pollution and rapid weather change. Air pollution is usually caused by the use of fossil fuels. To overcome the environmental issues, LIBs are reasonable candidates. In these days, lithium ion batteries (LIB) are very promising power suppliers for electronic devices, electrical vehicles (EV), and energy storage system (ESS) because of their high power densities.[1] Although the LIB has advantages compared to other power sources, LIBs with a liquid electrolyte have safety issues such as explosion and fire contributed by thermal or chemical instability. All-solid-state batteries are the solution to the problem of LIBs with liquid electrolytes. All-solid-state batteries have many advantages such as high energy densities, high stability, and applying high voltages compared to conventional LIBs.[2] As the portable and miniaturization of electronic devices and the development of wearable devices are to be in the spotlight, the development of a power supply for drive them is indispensable. The type of batteries that can meet this demand is an all-solid-state thin-film battery. Thickness of thin-film batteries is about 10 μm, which makes it suitable for power source of miniaturized electronic devices such as smart cards, RFID tags and medical devices. All-solid-state thin-film batteries also have better thermal stability than conventional Li-ion batteries. Higher capacity of thin-film batteries can be realized by applying high voltages. The key to the performance of all-solid-state thin-film batteries is a solid electrolyte. In order to deposit thin-film electrolytes, there are various available techniques such as a sputter, plasma laser deposition (PLD), e-beam evaporator, and so on. Among these techniques, the sputtering technique has an advantage compared to other deposition techniques. The sputtering techniques could deposit oxide and nitride materials. In addition, sputtering techniques are simple process and can be deposition with thin films uniformly. Comparing PLD and molecular beam epitaxy (MBE), the sputtering techniques are lower cost and low temperature for deposition. Therefore, sputters are suitable for commercialization. Generally, solid electrolytes are classified under oxide system and sulfide system. While sulfide electrolytes have high ionic conductivity and instability, oxide electrolytes have low ionic conductivity and high stability. A lot of oxide based solid state electroly